Method and device for reducing positive pressure in universal joint receiving actuation cylinder

Abstract

The present invention provides a method and device for reducing the positive pressure of a universal joint receiving working cylinder. The method is applied to a universal joint receiving working cylinder, and the device used in the method includes a foundation, a base frame, a force applying device, a direction adapting device, a universal swing rod device, and an integrated external connection device. The method includes the following steps: a first step of determining the main design parameters and the type of the force applying device; a second step of designing the device structure after determining the main design parameters and the type of the force applying device; and a third step of calculating, testing, and evaluating the effect of the actual gravity moment or positive pressure and weight compensation, judging whether it meets the design requirements, and calculating or testing and evaluating the gravity moment and reduction rate. The method solves the technical problem that the working cylinder has a large side force, which increases the power burden of the system.

Description

[Technical Field]

[0001] The present invention relates to the technical field of joint receiving mechanisms, and more particularly to a method and device for reducing positive pressure in a universal joint receiving actuation cylinder. [Background technology]

[0002] Nowadays, UPS (including UCS) type branches are widely used in many mechanisms. In such branches, the driving pair (P pair or C pair) is a hydraulic cylinder or an electric cylinder (hereinafter referred to as an actuating cylinder). For example, in a parallel mechanism (see Figure 1.1), the UPS type branch oscillates in space. The P pair of the UPS branch oscillates in two-dimensional space, that is, the working space of the branch is an inclined cone.

[0003] Such parallel mechanism systems have two main issues to be resolved: one is to reduce the frictional force of the actuating cylinder, and the other is to deal with the load caused by the weight of the actuating cylinder itself.

[0004] Regarding the issue of friction, it is necessary to reduce the friction of the leading joint. Currently, simulator specifications (MIL-S-87241) are used for US military aircraft, and the technical specifications for commercial flight simulators are also based on this standard. According to this specification, the friction force of the operating cylinder of the flight simulator motion system must be less than 0.3% of the maximum effective payload.

[0005] Friction in an actuating cylinder mainly includes friction caused by two factors: friction between the cylinder barrel and piston of the actuating cylinder, and friction between the cylinder head and piston rod. According to classical tribology theory, friction force is equal to the product of the friction coefficient and the positive pressure (hereinafter also referred to as side force). Side force is the sum of the positive pressure on the diameter of the cylinder barrel and piston of the actuating cylinder and the positive pressure on the diameter of the cylinder head and piston rod (also referred to as positive pressure). A decrease in either of the two factors, the friction coefficient or the positive pressure, will result in a decrease in friction force. Most of the methods currently used to reduce friction force are by reducing the friction coefficient. The effect of side force on friction force has not been studied much.

[0006] In practical applications, there are two main solutions to achieving a low friction coefficient: hydrostatic bearings and combined seals. Using hydrostatic bearings allows for an extremely low friction coefficient. However, hydrostatic servo oil cylinders require complex manufacturing processes and high manufacturing costs. They have limited resistance to side forces (excessive side forces can cause mechanical wear), a small output length, and a large power load. The combined seal method uses low-friction materials to form the friction pair. However, this method cannot withstand side forces, suffers from severe wear, and it is difficult to reduce the friction force to less than 1% of the total load. As a result, it cannot fully meet the smoothness required for flight simulators. Friction compensation and ultra-slip technologies have been developed, but the problem remains.

[0007] A literature search revealed that no effective solution for reducing friction by reducing side force was found. However, in the application environment of the flying simulator parallel mechanism, side force is one of the important factors that affect friction. Factors that affect side force include gravity, axial force, processing and assembly errors, seals, guides, etc. Furthermore, these several side forces interact with each other, further increasing side force.

[0008] Therefore, by reducing the side forces and reducing the mutual influence of the side forces, the frictional force due to the side forces can be effectively reduced.

[0009] Analysis revealed that among the many factors that affect side force, gravity is the main factor. A large side force due to gravity exists on the piston of the linear actuating cylinder and the guide sleeve of the cylinder head. Furthermore, this side force changes. The side force increases as the piston rod extends. When the axis of the actuating cylinder is horizontal and the piston rod reaches 70% extension, this side force is greater than the linear actuator's own weight and increases rapidly as the extension amount increases.

[0010] For example, in the case of a parallel mechanism motion system that drives a load of several tons, the weight of the electric cylinder alone will be several hundred kilograms or more, and in the application environment, this weight of several hundred kilograms will generate a considerable side force that will be much larger than the weight itself, especially when the relative output is large or the tilt angle is small.

[0011] Axial forces can also create side forces. Due to the eccentricity or deflection of the piston rod axis from the cylinder axis, axial thrust creates a bending moment. This bending moment increases the eccentricity, which in turn increases the bending moment, resulting in a larger side force. Gravity also increases this side force.

[0012] Seals and guides also create side forces. Seals require isotropic pressure distribution. However, gravity and axial forces disrupt this isotropy, destroying the sealing condition. To satisfy the sealing condition, the initial design requires a larger sealing force. This indirectly increases the side force and friction.

[0013] Such a relatively large side force is difficult for hydrostatic supports to withstand, which not only requires a large power support, but can also sometimes create mechanical friction, increasing frictional force and even shortening service life. In combination seals, large frictional force and significant wear occur. In the case of hydraulically driven actuating cylinders, an increase in side force significantly reduces the sealing effect. Therefore, side force is an unfavorable factor for both hydrostatic supports and combination seal supports.

[0014] The load of the motion platform is divided into two main parts: one is the motion platform structure and the load part above the platform, which is the main load of the motion platform; the other is the part below the motion platform, that is, the weight of the hydraulic cylinder or electric cylinder.

[0015] When the motion platform moves, the actuating cylinders move accordingly, raising and lowering their center of gravity. When the motion platform rises, the system raises the center of gravity of the electric cylinders, so the actuating cylinders also become part of the motion system's load. For example, a 4-ton electric motion platform uses six actuating cylinders, each weighing approximately 300 kg, for a total weight of approximately 1,800 kg. The weight of the actuating cylinders themselves accounts for a relatively large proportion of the platform's total weight. The current method used to solve the problem of load caused by the platform's own weight is pneumatic compensation. Pneumatic compensation requires a gas-driven system, and the larger the platform, the more cylinders are required to support it, making the structure more complex. Current pneumatic compensation methods address the issue of compensating for the weight of the entire platform, which typically accounts for about half of the platform's total weight.

[0016] As described above, the existing actuation cylinders for spatial tilt swing applications have the following problems. 1. Due to the influence of gravity, there are relatively large side forces (positive pressure) between the piston and cylinder body, and between the cylinder head and piston rod, which affect the performance of the working cylinder, including friction force and expansion / contraction amount. 2. The weight of the cylinder body is the load of the motion platform, which increases the power load of the system. Summary of the Invention [Problem to be solved by the invention]

[0017] The object of the present invention is to provide a method and apparatus for reducing the positive pressure in a universal joint receiving actuation cylinder, which solves the technical problem of the large side force present in the actuation cylinder, adversely affecting performance and increasing the power load of the system. [Means for solving the problem]

[0018] In order to achieve the above object, the present invention provides A method for reducing positive pressure in a universal joint receiving actuation cylinder, comprising: Applicable to universal joint receiving actuation cylinders, The device used in the method includes a base frame, a force application device, a direction adaptation device, a universal swing rod device, and an integrated external connection device; The method comprises: determining the main design parameters and type of force application device; Step A determines key design parameters, including the magnitude of the maximum positive pressure of the working cylinder to be reduced, the ratio of the maximum gravity moment to the gravity moment to be eliminated, the maximum anti-gravity moment, and the magnitude of weight compensation; determining the type and structural form of a force application device, wherein determining the type of force application device includes determining a force application method to be used to provide the anti-gravity moment, the force application method being one or a combination of two or more of a tension spring, a torsion spring, a gravity counterweight, a gravity pendulum, an air spring, or an electromagnetic force; a step B in which the structure form is determined, the structure form being one of an open loop structure, a closed loop structure, a semi-open loop structure, a semi-closed loop structure, and a hybrid structure, and the steps A and B may be performed simultaneously in any order; designing a device structure, a second step of carrying out a structural design of the device after determining the main design parameters and the type of the force application device, including structural design, manufacturing, assembly and debugging, where the structural design includes the design of a base frame, a force application device, a direction adaptation device and the integrated external connection device; and a third step of calculating, testing, and evaluating the actual gravity moment or positive pressure and the effect of weight compensation to determine whether the design requirements are met, calculating, or testing, and evaluating the gravity moment and reduction rate, calculating, or testing, and evaluating the effect of weight compensation, and if the design requirements are met, stopping and taking the above design proposal as the design result, and if the requirements are not met, adjusting the parameters and repeating the above steps to redesign until the design requirements are met.

[0019] The present invention provides A device for reducing positive pressure in a universal joint receiving actuation cylinder for realizing the method for reducing positive pressure in a universal joint receiving actuation cylinder, comprising: a base frame, a force application device, a direction adaptation device, and an integrated external connection device; The base frame includes an external connection device 1A, a frame body, and an external connection device 1B, the force applying device includes a force generating device, a force transmitting device, an external connection device 2A, and an external connection device 2B, and the force generated by the force generating device includes gravity, metal spring force, air spring force, or electromagnetic force; The direction adapting device includes two rotating pairs that are not coaxial and not parallel, and the external connection device 3A, the external connection device 3B and the two sliding pairs are fixedly connected together to enable two-degree-of-freedom rotation; The integrated external connection device provides a device including an external connection device 5A and an external connection device 5B. [Effects of the Invention]

[0020] The features and advantages of the present invention are as follows: Advantage 1: Reduces friction by partially or completely eliminating the side force (positive pressure) due to gravity. The hydraulic cylinder applied to hydrostatic support can reduce the lateral load and friction force, as well as reduce the energy consumption caused by hydrostatic oil supply, reduce the probability of mechanical friction wear, and extend the service life. When applied to a combined seal support, the positive pressure between the cylinder barrel and the piston rod can be significantly reduced (reducing or almost eliminating the positive pressure due to gravity, and simultaneously eliminating the associated positive pressure), thereby significantly reducing friction, reducing wear, and extending the life. Therefore, the side force reduction device can provide a high-performance flight simulator for applying a conventional combined seal system. Advantage 2: Offsets all (possibly more) or most of the weight of the actuating cylinder. Reduces or eliminates the gravity load due to the weight of the electric cylinder itself. Offsets a portion of the platform weight. Provides load capacity, reducing the burden of pneumatic compensation or in some cases allowing the pneumatic compensation to be removed. Advantage 3: It reduces or eliminates the side force caused by gravity, and has the following effects: 1. It reduces the eccentricity of the axis of the working cylinder, thereby reducing the side force caused by axial thrust. 2. It improves the symmetry of the force around the piston, and appropriately reduces the sealing pressure, which can further reduce friction force. 3. If auxiliary measures such as friction compensation are used, it can reduce the difficulty of friction compensation or improve the effectiveness of friction compensation.

[0021] The following drawings are only for illustrative purposes of the present invention and are not intended to limit the scope of the present invention. [Brief explanation of the drawings]

[0022] [Figure 1-1.10] 1 to 1.10 are schematic structural diagrams of the first embodiment. [Figure 2-2.4] 2 to 2.4 are schematic structural diagrams of the second embodiment. [Figure 3-3.2] 3 to 3.2 are schematic structural diagrams of the third embodiment. [Figure 4] FIG. 4 is a structural schematic diagram of the fourth embodiment. [Figure 5] FIG. 5 is a structural schematic diagram of Example 5. [Figure 6-6.1] 6 to 6.1 are schematic structural diagrams of the sixth embodiment. [Figure 7] FIG. 7 is a structural schematic diagram of Example 7. [Figure 8] FIG. 8 is a structural schematic diagram of Example 8. [Figure 9-9.2] 9 to 9.2 are structural schematic diagrams of Example 9. [Figure 10-10.4] 10 to 10.4 are structural schematic diagrams of the tenth embodiment. [Figure 11-11.1] 11 to 11.1 are structural schematic diagrams of the eleventh embodiment. [Figure 12-12.1] 12 to 12.1 are structural schematic diagrams of the twelfth embodiment. [Figure 13-13.1] 13 to 13.1 are structural schematic diagrams of the thirteenth embodiment. [Figure 14-14.1] 14 to 14.1 are structural schematic diagrams of the fourteenth embodiment. [Figure 15] FIG. 15 is a structural schematic diagram of Example 15. [Figure 16-16.1] 16 to 16.1 are schematic structural diagrams of the sixteenth embodiment. [Figure 17-17.1] 17 to 17.1 are structural schematic diagrams of Example 17. [Figure 18] FIG. 18 is a structural schematic diagram of Example 18. [Figure 19] FIG. 19 is a structural schematic diagram of Example 19. [Figure 20-20.1] 20 to 20.1 are schematic structural diagrams of the 20th embodiment. [Figure 21]FIG. 21 is a structural schematic diagram of Example 21. DETAILED DESCRIPTION OF THE INVENTION

[0023] To provide a method, device, and system for effectively reducing or eliminating side forces due to gravity in UPS-type branches receiving tiltable universal joints, and to provide a method, device, and system for partially reducing the weight load of a motion system, or to separately provide a method and device for partially reducing the weight load of a motion system.

[0024] The UPS-type branches in this specification include, but are not limited to, UPU, SPR, UPR, UCU, UCR, UCU, UCS, SPS, SCS, (RUR)CS, (UR)CS, SCS, (RR)CS, (RRR)CS, URCS, URPU, U(RHR)U, etc. The leading pair is one of P, C, and H. The parallel mechanism is a 2- to 6-DOF parallel mechanism.

[0025] Figure 1 is a schematic diagram of the structure of Example 1, Figure 1.1 is a schematic diagram of the 6-UPS 6-degree-of-freedom parallel mechanism structure, Figure 1.2 is a force analysis diagram of the anti-gravity moment of Example 1 (in a vertical plane passing through the axis of the actuating cylinder), Figure 1.3 is a force analysis diagram of the anti-gravity moment of Example 1 (projected onto a horizontal plane), Figure 1.4 is a schematic diagram of the actuating cylinder structure, Figures 1.5 to 1.9 are schematic diagrams of several connection methods between the force-adding device and the actuating cylinder (or connecting rod), and Figure 1.10 is a schematic diagram of a symmetrical spherical hinge with four orthogonal axes.

[0026] Figure 2 is a structural schematic diagram of Example 2, Figure 2.1 is a structural schematic diagram of the sleeve spring, Figure 2.2 is a partial view (C1 direction) of the force application device in Figure 2, Figure 2.3 is an example of the structure of the connecting rod in Figure 2, and Figure 2.4 is a schematic diagram of the flexible connection method of the force application device (combination of the force application device and the direction adaptation device).

[0027] Figure 3 is a structural schematic diagram of Example 3 (closed loop, no support disk, tension force generated by cable and torsion spring, no cable direction change), and Figures 3.1 and 3.2 show two types of force generating devices of the force application device of Example 3. These are also used in Example 5.

[0028] Figure 4 is a structural schematic diagram of Example 4 (closed loop, no support disk, tension spring, one change in cable direction). Figure 5 is a structural schematic diagram of Example 5 (closed loop, no support disk, tension force by torsion spring, one change in cable direction).

[0029] Figure 6 is a schematic diagram of the structure of Example 6 (closed loop, no support disc, tension spring, cable direction changed twice), and Figure 6.1 is an improved diagram of Example 6.

[0030] FIG. 7 is a schematic diagram of the structure of Example 7 (closed loop, no support disk, tension force generated by gravity pendulum and cable, cable direction changed twice), and FIG. 8 is a schematic diagram of the structure of Example 8 (closed loop, support disk, tension spring, cable direction changed twice).

[0031] Figure 9 is a schematic diagram of the structure of Example 9 (closed loop, with support disk, tension spring, vertical rod connected to cable, cable direction changed once), Figure 9.1 is its top view, where the springs are placed on both sides of the actuating cylinder, and Figure 9.2 is an improvement of Example 9 (small closed loop changed to large closed loop).

[0032] Figure 10 is a structural schematic diagram of Example 10 (small closed loop, with support disk, torque generated by torsion spring), Figure 10.1 is a top view of Figure 10, Figure 10.2 is a diagram of the torsion spring mounting position and force analysis, Figure 10.3 is a schematic diagram of the stiffness selection of the torsion spring, and Figure 10.4 shows an example of a large closed loop, which is an improvement of Example 10.

[0033] FIG. 11 is a structural schematic diagram of Example 11 (with support disk, direct counterweight form), FIG. 11 is its side view, and FIG. 11.1 is a top view of Example 11.

[0034] Figure 12 is a structural schematic diagram of Example 12 (with support disk and gravity indirect counterweight on both sides (direction change by gear)), and Figure 12.1 is its top view.

[0035] Figure 13 is a structural schematic diagram of Example 13 (small closed loop, support disk, three direction changes by cable-type spring, spring attached to ground, hybrid configuration), and Figure 13.1 is a partial structural diagram of the third direction change.

[0036] Figure 14 is a structural diagram of Example 14 (with support disk, gravity counterweight + tension spring), and Figure 14.1 is its top view. Figure 15 is a structural diagram of Example 15 (open loop, tension spring, foldable base frame, hollow direction adapting device).

[0037] Figure 16 is a schematic diagram of the structure of Example 16 (semi-open loop, with support disk, tension force generated by torsion spring, with coupling), and Figure 16.1 is an improvement of Example 16, where the semi-open loop is changed to a large open loop and a U-shaped fork is attached.

[0038] Figure 17 is a structural schematic diagram of Example 17 (semi-open loop, with support disc, torque generated by torsion spring), and Figure 17.1 is an improvement of Example 17, changing the semi-open loop to a large open loop (for clarity, Figure 17.1 shows a freely swinging connecting rod device (with actuating cylinder), but this device is not present in the open loop configuration).

[0039] Figure 18 is a structural diagram of Example 18 (large open loop, bearings on the support disk, not shared, anti-gravity moment generated by counterweights on both sides, coupling synchronization). Figure 19 is a structural diagram of Example 19 (system form 1, no support disk, cable spring direction changed twice, small inertia).

[0040] Figure 20 is a structural schematic diagram of Example 20 (system form 2, with support disc, torque generated by torsion spring), and Figure 20.1 is a structural schematic diagram of an improved Example 20 (with support disc, torsion spring is a cable spring on one side, two axes become one).

[0041] FIG. 21 is a structural schematic diagram of Example 21 (system form 3 with support disk and motor weight counterweight).

[0042] 1st part In this section, open loop methods are described, and the methods described in this section do not include universal swing rod device methods.

[0043] The method for reducing positive pressure in a universal joint receiving actuation cylinder is applicable to a universal joint receiving actuation cylinder, and the device includes a base frame, a force applying device, a direction adapting device, and an integrated external connection device, and the method for reducing positive pressure in a universal joint receiving actuation cylinder includes the following steps:

[0044] First step: determine the main design parameters and type of force application device.

[0045] A. Determine the main design parameters, i.e., for a given application (universal joint-receiving actuating cylinder, i.e., UPS type branch) and design requirements, the main parameters include the magnitude of the maximum positive pressure to be reduced, the ratio of the maximum gravity moment (the moment that the weight of the actuating cylinder exerts on the joint-receiving point when it is horizontal) to the gravity moment (or positive pressure) to be eliminated, the maximum anti-gravity moment, the main structural size and characteristics of the application (parallel mechanism), and the magnitude of gravity compensation.

[0046] The main structural dimensions of the applicable object include the working space of the universal joint-receiving actuating cylinder, i.e., the pitch angle, yaw angle, and weight of the actuating cylinder. The maximum gravitational moment includes the weight of the actuating cylinder when its axis is horizontal and the moment that some additional weight imparts to the joint-receiving point. The additional weight is, for example, the gravity and gravitational moment that a force-adding device imparts to the actuating cylinder. The maximum anti-gravity moment is the product of the ratio of the gravitational moment and the gravitational moment that it cancels. Usually, the corresponding engineering error is also given.

[0047] The maximum positive pressure is the sum of the absolute value of the positive pressure at the piston (between the piston and the cylinder body) and the absolute value of the positive pressure at the cylinder head (between the piston rod and the cylinder head) when the working cylinder is horizontal. This positive pressure is one of the factors that cause friction in the working cylinder.

[0048] The gravity moment includes the gravity moment due to the weight of the universal joint receiving actuation cylinder itself, as well as an additional gravity moment formed when the weight of the force applying device, connecting rod, etc. acts on the actuation cylinder. Before designing the first form, it is necessary to estimate the gravity moment (referred to as ML) that the weight of the force applying device imparts to the actuation cylinder. If data from a similar previous design proposal is available, this data may be referenced to set the gravity moment.

[0049] There are several cases in which the gravity moment that the weight of the force-applying device imparts to the actuating cylinder. For example, in Examples 4, 5, and 6, the gravity moment is mainly due to the weight of the connecting part, but in Example 1, the weight of several springs is also included, and in Examples 2 and 3, the weight of the connecting rod is also included. In many cases, the gravity moment that is created is positive, but some of the gravity moment that is created is beneficial. For example, in some of the counterweight examples, the gravity moment created by the connecting device is a beneficial anti-gravity moment that reduces the gravity moment.

[0050] There are two ways to determine the gravity moment: one is to determine the gravity moment according to the actual application, and the other is to classify the motion platform and design it by classifying the gravity moment according to parameters such as the weight of the motion platform branches, the gravity moment of the branches, and the main requirements of each grade, so that it can meet the needs of various application scenarios. For example, the weight of the working cylinder can be divided into multiple grades such as 50, 100, 200, 300, and 400 kg.

[0051] The rate of gravity moment elimination is the percentage of gravity moment to be removed or the magnitude of weight compensation, and is determined by the designer. When considering both positive pressure reduction and weight compensation, this rate is typically 50% to 150%, and most preferably 100% to 120%. When considering only reducing positive pressure to a minimum (minimum friction force to be pursued), this rate is typically 95% to 105%, and most preferably 100%. If the elimination rate is 100%, theoretically, the positive pressure at the design point is minimized, and weight compensation is also the weight of the working cylinder.

[0052] The magnitude of the reduced positive pressure or antigravity moment is related to the magnitude of the weight compensation. If an 80% positive pressure reduction is required, the antigravity moment may be 80% or 120% (i.e., corresponding to two configurations). The 120% antigravity moment configuration provides 40% more weight compensation than the 80% antigravity moment configuration. 100% positive pressure corresponds to one antigravity moment configuration and one weight compensation configuration. If the requirement for positive pressure reduction is not very high but the requirement for weight compensation is high, an antigravity moment slightly greater than 100% may be selected.

[0053] From the above, when weight compensation and positive pressure reduction are taken into consideration comprehensively, an antigravity moment of 100% to 120% may be selected. If weight compensation is prioritized, an antigravity moment much greater than 100% is also a feasible form.

[0054] If we only consider weight compensation without considering the reduction of frictional force, this ratio may be 150% or more, for example, 200% or 300% of the antigravity moment. In this way, a large weight compensation is obtained. At an antigravity moment greater than 200%, the frictional force is larger than without the antigravity moment.

[0055] B. Determine the type of force application device and the overall configuration of the structure.

[0056] Determining the type of force application device means determining the force application method for supplying the anti-gravity moment, including, but not limited to, the following methods:

[0057] One or a combination of two or more of the force application methods of tension spring, compression spring, torsion spring, air spring, gravity counterweight, gravity pendulum, and electromagnetic force can be selected.

[0058] Determine the structure type. The structure type includes an open loop structure, a closed loop structure, a semi-open loop structure, a semi-closed loop structure, a hybrid structure, etc. Select one of these structure types.

[0059] Steps A and B may be performed simultaneously, in any order.

[0060] For example, in Examples 1 and 2, a tension spring is used as the force application method, resulting in a closed loop structure; in Examples 3, 4, 5, and 6, a combination of a tension spring and a cable is used as the force application method, resulting in a closed loop structure; in Example 17, the parameter torque of a torsion spring is used as the force application method, resulting in a semi-open loop structure; in Examples 11 and 12, a gravity counterweight is used as the force application method; and in Example 14, a mixed method is used as the force application method.

[0061] Second step: concrete structural design Specific structural design includes structural design, manufacturing, assembly, debugging, etc. (abbreviated as structural design, and structural design includes simulation design, assembly, and debugging).

[0062] The structural design includes the design of the base frame, force application device, direction adaptation device, and integrated external connection device.

[0063] The base frame acts as a mount (direct or indirect) for other members. The force applying device supplies an appropriate force, which acts between the coupling-receiving actuation cylinder and the mount to create an appropriate anti-gravity moment and an appropriate weight compensation, and at each pitch angle, the supplied anti-gravity moment and weight compensation meet the design requirements.

[0064] The direction adaptation device provides the force application device with a working space that matches the working space of the actuating cylinder, ensuring that the anti-gravity moment remains the same or changes only slightly when the yaw angle changes.

[0065] The integrated external connection device is used to connect the actuating cylinder and mount the entire device, and connect to the task load.

[0066] The above-mentioned moving parts cooperate with each other to provide anti-gravity moment and weight compensation that meet the design requirements when the pitch angle of the UPS branch changes. When the yaw angle changes, the anti-gravity moment remains unchanged or changes slightly within the engineering tolerance range, and the weight compensation remains unchanged or changes slightly within the engineering tolerance range, for example, 5% or less. That is, the changes in the anti-gravity moment and weight compensation are within the engineering tolerance range.

[0067] Third step: Calculate, test and evaluate the effect of the actual gravity moment or positive pressure and weight compensation to determine whether it meets the design requirements.

[0068] The gravity moment (due to the weight of the operating cylinder, force application device connection parts, etc.) and reduction rate are calculated, or tested and evaluated, and the weight compensation effect is calculated, or tested and evaluated. If the design requirements are met or nearly met, the system is stopped. The above configuration is the design result.

[0069] If the requirements are not met, the parameters are adjusted and the above process is repeated until the design requirements are met.

[0070] The parameters to be adjusted further include, but are not limited to, the anti-gravity moment, the reduction rate, the force application method, the structure shape, the structure size, the structure inertia, such as whether or not a slewing bearing is used, the type of force application method used, etc.

[0071] Parameter adjustment involves changing the weight of the connecting device (the weight of the connecting device in the design proposal) ML, or adjusting the force application device or structure, or adjusting two or more of them, and in some cases taking into account the inertia of the application device and the perturbation space of each member of the system.

[0072] The design is reworked and the above process is repeated until the design requirements are met. This is an iterative process.

[0073] The device according to the above method is an open loop device, which is called an open loop side force reduction device, and can be directly applied to a parallel mechanism (connected to the operating cylinder of the UPS-like branch of the parallel mechanism).

[0074] 2nd part In this section, a closed loop method is described, which includes a method for constructing a configuration of a universal joint receiving actuation cylinder.

[0075] As mentioned above, the method also includes a universal swing rod device or a universal joint-supported actuating cylinder (i.e., UPS-type branch) branch (these three names are sometimes interchangeable). Therefore, the method also requires the design of a universal swing rod device. The integrated external connection device also changes. While the connection between the base frame and the foundation remains the same, one end of the original force-applying device is connected to the swing rod device of the universal swing rod device, and the swing rod device becomes part of the integrated external connection device. In this way, a closed-loop structure is obtained, which is abbreviated as a closed-loop universal joint-supported actuating cylinder side force reduction device (closed-loop side force reduction device or closed-loop positive pressure reduction device). The closed-loop side force reduction device is applicable to parallel mechanisms or UPS-type branches (including RPS branches or PS and CS branches that share the same revolving pair). The universal swing rod device provides the mounting base and swinging space for the actuating cylinder. In some cases, an actuating cylinder is used instead of the connecting rod of the universal swing rod device. The connecting rod arrangement may be parallel, perpendicular, opposite or otherwise oriented relative to the axis of the actuating cylinder, with the connecting rod lying in a vertical plane passing through the axis of the actuating cylinder.

[0076] Therefore, based on the method of the open-loop side force reduction assembly, by making appropriate adjustments, a method of reducing the side force of the universal joint receiving actuation cylinder by the closed-loop side force reduction device can be obtained. Since the open-loop method can be referred to, it will not be described in detail here.

[0077] The second step of the open loop method also includes a method of attaching a first swivel pair of the direction adaptation device to the foundation with its axis perpendicular to the horizontal plane, thereby simplifying the structure and improving accuracy, and this swivel pair is called a slewing bearing, and the fixed disk of this slewing bearing is fixed to the foundation, and the support disk is fixedly attached to the rotating disk of this slewing bearing. The slewing bearing is also part of the stand frame, and the support disk is attached to the remaining part of the base frame, and another swivel pair of the direction adaptation device is attached to the support disk. See the embodiment of the open loop with slewing bearing.

[0078] In the second step of the closed-loop method, the universal swing rod (i.e., the UPS branch) and the direction adapting device share the same swivel pair, simplifying the structure and improving accuracy. The shared swivel pair is the swivel pair connecting the universal joint of the universal swing rod device to the foundation, and is called a swivel bearing. The axis of the swivel bearing is perpendicular to the horizontal plane, the fixed disk of the swivel bearing is fixed to the foundation, and a support disk is fixed to the upper surface of the rotating disk of the swivel bearing. The swivel bearing also functions as part of the base frame. Another swivel pair of the direction adapting device is attached to the support disk, and the remaining part of the UPS branch is attached to the support disk. Usually, the axes of the swivel pairs of the other two bearings are parallel to the horizontal plane. See Examples 8 and 9 of the closed-loop with swivel bearing.

[0079] In application, the remaining portion of the UPS branch is also attached to the support disk. In the force application device, one end connected to the base frame may be connected to the support disk or foundation.

[0080] In this specification, the UPS branch and the free-swinging connecting rod refer to the same device.

[0081] 3rd part In this section, the structural open loop assembly configuration is described, with reference to open loop Example 15.

[0082] The positive pressure reducing device for a universal joint receiving actuation cylinder includes a base frame 1, a force applying device 2, a direction adapting device 3, and an integrated external connecting device 5. The former three parts are the functional structure body. All open loop configurations include these main parts. The closed loop configuration also includes a freely swinging connecting rod device 4.

[0083] 1. The base frame includes an external connection device 1A, a frame body, and an external connection device 1B. The base frame is a structure or mechanism with 0 to 2 degrees of rotational freedom. It functions as a mounting for other components such as a direction adapting device or a force applying device.

[0084] 2. The force application device includes a force generation device, a force transmission device, an external connection device 2A, and an external connection device 2B. The force generation device is composed of gravity, metal spring force, air spring force, electromagnetic force, etc., but is not limited to these forces. The force transmission device is used to transmit force and change the magnitude and direction of force. The force applying device applies a force generated by the force applying device between the base frame and the connecting rod (or the operating cylinder) of the freely swinging connecting rod device, thereby applying an anti-gravity moment to the operating cylinder.

[0085] 3. The direction adapting device includes two non-coaxial, non-parallel swivel pairs and external connection devices 3A and 3B. The two swivel pairs are fixedly connected together, allowing two degrees of freedom of rotation.

[0086] The direction adapting device ensures that the working cylinder rotates up and down around the horizontal axis, and in combination with the force applying device, realizes the change of direction and provides the appropriate anti-gravity moment. When the working cylinder rotates around the vertical axis, the force applying device performs a corresponding movement.

[0087] The integrated external connection device 5 includes an external connection device 5A and an external connection device 5F, and is responsible for fixing the entire device and outputting to the outside.

[0088] whole structure The base frame 1 is mounted near (outside or around) the universal joint 4.2 (the U-joint of the UPS branch), the direction adapting device 3 is mounted on the base frame, one end of the force applying device 2 is connected to the base frame by the direction adapting device, and the other end of the force applying device is connected to the freely swinging connecting rod or cylinder body by a connecting device, i.e., one end acts on the working cylinder and the other end acts on the base frame. When the base frame, force applying device, direction adapting device and freely swinging connecting rod device form a closed loop, synchronous rotation is realized.

[0089] The integrated external connection device 5 is connected to the foundation and external equipment to realize these basic functions.

[0090] Installation and Use This side force reduction device is applied to a parallel mechanism. When the universal joint and parallel mechanism are in their reference positions, a first end of the connecting device of the side force reduction device is attached to the outside or the periphery of the universal joint. A second end of the connecting device 1 is connected to the actuating cylinder.

[0091] The above components cooperate with each other to form an appropriate anti-gravity moment throughout the working space of the working cylinder and between the working cylinder and the base frame, thereby reducing or partially eliminating the moment (hereinafter simply referred to as the gravity moment) due to the gravity of the working cylinder (which may include the weight of the piston rod) acting on the center of the UPS branch U-pair of the tilt joint support, thereby reducing positive pressure and friction. Also, the gravitational effect of the working cylinder is reduced or partially eliminated, thereby reducing the power load of the system.

[0092] 4th part In this section, a semi-open loop configuration is described, with reference to semi-open loop Example 17.

[0093] In the open loop configuration, in the universal joint-received actuation cylinder positive pressure reducing device, the first swivel pair of the direction adaptation device is attached to the ground. The axis of this swivel pair is perpendicular to the ground. A swivel bearing is usually used as this swivel pair, with the fixed disk of the swivel bearing fixed to the foundation and the movable disk usually fixedly connected to the support disk, to which another swivel pair of the direction adaptation device is attached. The swivel bearing becomes part of the stand frame. The stand frame becomes a one-degree-of-freedom stand frame. The remaining part of the base frame is attached to the support disk. The fixed disk of the swivel bearing is attached to the foundation.

[0094] In the closed loop embodiments 8, 9, and 10, this semi-open loop structure can be obtained simply by removing the horizontal axis pair of the universal joint and the connecting rod.

[0095] In use, the support disc is also used to mount the remainder of the UPS branch, for example the RPS section.

[0096] The U-joint of a UPS branch has two swivel joints, or three swivel joints if a spherical hinge is used instead of a universal joint. The swivel joint connected to the base is called the first swivel joint, and those above it are called the second, third, and so on. Positive pressure, as described herein, is sometimes called side force, and these actually mean the same thing.

[0097] There are two types of open loop configurations: large open loop and semi-open loop. An open loop is a configuration that does not include a freely swinging connecting rod device. If the direction adapting device shares the first swivel pair with the universal joint of the universal joint connecting rod, it is called a semi-open loop structure. Otherwise, it is a large open loop. The shared first swivel pair is called a swivel bearing. This swivel bearing can withstand a certain overturning force. The semi-open loop structure is a simplified version of the large open loop structure. A large open loop is also called an open loop.

[0098] 5th part In this section, a closed loop structure is explained in which a freely swinging connecting rod device is added based on the open loop structure to form a closed loop structure, and reference is made to Examples 1 to 6.

[0099] This positive pressure reduction device for a universal joint-received actuating cylinder includes a base frame, a force application device, a direction adaptation device, a freely swinging connecting rod device, and an integrated external connection device 5A, 5F. The base frame, force application device, and direction adaptation device are similar to those of the open loop configuration and will not be described in detail. One end of the universal joint of the freely swinging connecting rod is attached to the foundation (or the bottom of the base frame), and one end of the swinging connecting rod is connected to the actuating cylinder and the force application device, which applies an anti-gravity moment to the actuating cylinder or connecting rod. The base frame, force application device, direction adaptation device, and freely swinging connecting rod form a closed loop, achieving synchronous movement of each component.

[0100] The entire structure is called a functional structure, which is composed of four components: the base frame, the force application device, the direction adaptation device, and the freely swinging connecting rod. The external connecting device includes a foundation connecting base and an actuating cylinder connecting base or a platform connecting base.

[0101] In one embodiment, the swingable connecting rod device includes a universal joint, a swinging connecting rod, an external connection device 4A, and an external connection device 4B. The universal joint (or spherical hinge) is connected to the swing rod. Universal joints include, but are not limited to, U, RR, RU, UR, RUR, and S mechanisms. The connecting rod may be on a line passing through the axis of the actuating cylinder or parallel to the axis of the actuating cylinder, on a plane perpendicular to the axis of the actuating cylinder, or on an extension of the axis of the actuating cylinder. The connecting rod may be a straight rod or a bent rod. Function: Provides a two-degree-of-freedom operating space for the actuating cylinder (branch), provides a connection interface with the RPS or PS branch, a connection interface with the force-applying device, and forms a whole with the parallel mechanism.

[0102] Installation and Use: See Example 20.

[0103] There are two types of closed loop configurations: large closed loop and semi-closed loop. In the closed loop configuration, the horizontal axis rotation pair of the direction adaptor and the first rotation pair of the universal joint share the same rotation bearing. This configuration is called a semi-closed loop configuration (see Examples 8 and 9). The large open loop is sometimes simply called an open loop.

[0104] In Examples 8, 9 and 10, the slewing bearing shares the same vertical axis rotation pair as the direction adaptation device.

[0105] This slewing pair usually uses a slewing bearing. The fixed disc of the slewing bearing is fixed to the foundation and the mobile disc is usually fixedly connected to a support disc, to which another slewing pair of the direction adaptation device is attached. The slewing bearing becomes part of the stand frame. The stand frame has one rotational degree of freedom. The remaining part of the base frame is attached to the support disc. The fixed disc of the slewing bearing is attached to the foundation.

[0106] In use, the support disc is also used to mount the remainder of the UPS branch, for example the RPS section.

[0107] The U-joint of a UPS class branch has two swivel joints, or three swivel joints if spherical hinges are used instead of universal joints. The swivel joint connected to the base is called the first swivel joint, and those above it are called the second, third, and so on.

[0108] The positive pressure described in this specification may also be called side force, which actually means the same thing. Details of each component will be explained uniformly (regardless of whether it is an open loop or a closed loop).

[0109] In one embodiment, the base frame includes a base mounting base 1A1.1, a frame body, and an upper mounting base 1B1.2. The base mounting base is connected to the periphery of the UPS branch on the ground foundation. The upper mounting base is connected to a direction adapting device or a force applying device.

[0110] The base frame serves as a mounting mount for the force applying or orientation adapting device and provides suitable attachment points.

[0111] There are three types of base frames: First type of base frame: The main frame is a rigid structural frame (see Example 1), or has two adjustable translational degrees of freedom (height, width), which can be adjusted to become a rigid frame (see Example 2).

[0112] The second type of base frame is a base frame with a rotational degree of freedom around a vertical axis (Examples 8 and 9). This vertical axis rotational joint is shared with the first rotational joint of the direction adaptation device. Usually, this rotational joint uses a swivel bearing and includes a swivel bearing, a support disk, and a mount. In such a case, two adjustable translational degrees of freedom may be set. See Examples 11 to 15.

[0113] The third type is a two-degree-of-freedom base frame, with one vertical axis rotational joint and one horizontal axis rotational joint. The two rotational joints are shared with the two rotational joints of the direction adaptation device. See Example 11. The axis of the slewing bearing rotating around the vertical axis is allowed to have an error of about 10 degrees, which has little effect on accuracy and allows the pitch operating space of the working cylinder to be increased.

[0114] In one embodiment, the force application device includes a force generation device 2.2, a force transmission device 2.3, an external connection device 2A2.1, and an external connection device 2B2.4. Structure: The force generation device and the force transmission device are connected in series. Both ends of the series connection have connection devices 2A and 2B. If a cable is present, it is also connected to a pulley.

[0115] The force transmission device has one end connected to the actuator and the other end connected to the base frame by a direction adaptation device.

[0116] The force application device generates an appropriate force and applies it between the electric cylinder and the base, applying an anti-gravity moment to the electric cylinder (definition: an anti-gravity moment is a moment in the opposite direction to the gravitational moment and is used to eliminate or reduce the gravitational moment).

[0117] The force generating device provides an appropriate force when the actuating cylinder rotates. Depending on the force generating method, it may include, but is not limited to, tension springs, compression springs, torsion springs, air springs, permanent magnetic springs, electric springs, gravity, moment motors, etc. One or more types may be combined and connected in parallel or series.

[0118] A force transmission device is a simple connection base or a simple cable (rope) transmission, or a combination of cables, transmission boxes, and pulleys. A force transmission device transmits force or changes the direction or magnitude of force.

[0119] The force transmission device of the force application device includes a pulley and a cable, and the pulley fixes or changes the direction of the cable. The first pulley determines the force application direction of the force application device and provides a rational force component. The second pulley cooperates with the first pulley to determine the direction of the second section of the cable, ensuring that the second section of the cable is perpendicular to the ground and blocking the yaw-induced swing of the actuating cylinder. The third pulley further changes the direction of the cable and provides an appropriate mounting position for the force application device.

[0120] The cable and pulley combination may be one of several:

[0121] A. One pulley The pulley is attached to the base frame and shares the same horizontal axis pair as the direction adapting device, fixing the direction of the first section of the cable and cooperating with the force applying device to orient the second section of the cable perpendicular to the horizontal plane and bring the cable axis close to the universal joint.

[0122] B. Two pulleys One pulley is attached to the base frame and shares the same horizontal axis as the direction adaptor, fixing the direction of the first section of cable, while the other pulley is attached to the base frame and works together to orient the second section of cable perpendicular to the horizontal plane and with its axis close to the universal joint. The third section of cable has a relatively flexible direction.

[0123] C. Three or more pulleys One pulley is attached to the base frame and shares the same horizontal axis as the direction adaptor, fixing the direction of the first section of cable, and the other pulley is attached to the base frame, and these two pulleys work together to orient the second section of cable perpendicular to the horizontal plane and keep the cable axis close to the universal joint. The remaining pulleys change the direction of any section of cable as desired. Any of these configurations may be connected in series with the reduction case. In particular, general air springs (as well as magnetic springs) have a small displacement. To obtain a large displacement, a transmission is used to increase the output displacement of the air spring. In order to easily change the initial force, an adjustment device for changing the initial force is connected in series to a certain portion of the force application device, for example, between the force generation device and the force transmission device, between the force generation device and the base frame, or between the force transmission device and the base frame, and is locked after adjustment.

[0124] In one embodiment, the direction adaptation device includes two turning pairs and two external connection devices 3A, 3B.

[0125] The two swivel joint axes of the direction adaptation device are most preferably orthogonal (coplanar or non-coplanar). The two swivel joints are connected by a rigid mount. The swivel joints may be conventional swivel joints or flexible swivel joints. The direction adaptation device is not limited to universal joints; for example, any combination of SR, RU, and RUR can be used.

[0126] The structure of the direction adaptation device can be divided into two types: a rotating joint concentrated arrangement structure and a top-bottom arrangement structure (embodiment with a rotating bearing).

[0127] In one embodiment, in a universal joint receiving swing rod arrangement, the universal joint and the connecting rod are fixedly connected together. The universal joint connecting rod arrangement can take several forms:

[0128] The connecting rod may be parallel to the axis of the actuating cylinder (see Example 2 and Example 3), perpendicular to the axis of the actuating cylinder (see Example 9), or below the axis of the actuating cylinder (see Example 11). For configurations in which the actuating cylinder is used as the connecting rod, see Examples 1, 4, and 5.

[0129] The difference between the actuating cylinder connecting rod device and the UPS branch is that the former includes the UPS universal joint and the cylinder body or the rod member connected to the cylinder body (example), but generally does not include the actuating cylinder or the motion platform universal joint. In some cases, they may be interchangeable if there is no confusion.

[0130] The connecting rod has a swivel mounting base, the position of which on the connecting rod may be adjusted to vary the magnitude of R1.

[0131] Various universal joints suitable for parallel mechanisms. (Universal joint types include, but are not limited to, RR, RU, RUR, S, and UR.) (Flush, non-flush, first turning pair perpendicular to the ground, first turning pair parallel to the ground, and other configurations with randomly arranged axes. May vary depending on the parallel mechanism. In some cases, the universal joints are the same but the mounting methods of the universal joints are different. If the branches are the same, different mounting methods will result in different parallel mechanisms.)

[0132] In one embodiment, the integrated external connection device includes a base connection device 5A and an actuation cylinder connection device 5B.

[0133] The foundation connection device allows connection with the ground, such as a fixed disk of the slewing bearing or a connecting base device of the base, and serves to fix the entire device. The actuation cylinder connection device allows connection with the actuation cylinder or platform, and is integrated with the parallel mechanism.

[0134] The force application device and direction adaptation device are designed with protective devices such as hoods and shells. The force generation device is designed with a length adjustment device. In order to obtain an accurate anti-gravity moment, the force application device is designed with force sensors and other sensors.

[0135] Part 6 In this section, the system assembly configuration is described and includes a micro-positive pressure parallel mechanism system.

[0136] Structure: The parallel mechanism includes three parts: a parallel mechanism, a side force reduction device, and external system connection devices 7A and 7B (the above open-loop and closed-loop assembly forms are called side force reduction devices). The parallel mechanism has at least one UPS-like branch, and at least one UPS-like branch is equipped with a side force reduction device (open-loop or closed-loop) to eliminate most of the side force of this UPS branch and eliminate part of the gravity of this branch (in some cases, it may be slightly larger than the weight of the actuation cylinder to offset the larger platform weight), thereby achieving a large parallel mechanism system with low side force, low friction, and partial gravity compensation characteristics. For various closed-loop and open-loop structures, see related Examples 19, 20, and 21.

[0137] The parallel mechanism has at least one branch that is a UPS-like branch, and works in conjunction with an open-loop or closed-loop side force reduction device to form a large system, i.e., a low-friction parallel mechanism system. The parallel mechanism has five degrees of freedom, i.e., 2, 3, 4, 5, and 6, or a combination of these degrees of freedom.

[0138] One or more of the above open-loop and closed-loop side force reduction devices are selected (the same number as the number of UPS branches is required). One side force reduction device is installed for each UPS branch.

[0139] The external connection device includes a foundation mounting base and a platform connection base. The foundation mounting base is the foundation platform of the parallel mechanism and the foundation mounting base of the side force reduction device. The platform connection base is a motion platform for mounting a task load, such as a cabin.

[0140] When a closed loop side force reduction device is used, the universal joint of the parallel mechanism is not required because there is a branch universal joint in the closed loop side force reduction device, and both share the same universal joint.

[0141] The base frame of the side force reduction device is attached near the bottom ends of the six branches of the six degrees of freedom, one end of the force application device is connected to the base frame by a direction adaptation device, and the other end of the force application device is connected to the connection base of the cylinder barrel of the working cylinder by a connection device, that is, one end acts on the working cylinder and the other end acts on the base frame. Each UPS branch has a corresponding side force reduction device.

[0142] In addition, the perturbation spaces of the branches and platforms of the parallel mechanism are spaces that cannot be occupied, and when installing the side force reduction device, the perturbation spaces cannot be occupied. In addition, an appropriate distance from the spaces is required.

[0143] The above components cooperate with each other to generate an appropriate moment (opposite to the gravity moment) between the actuator and the base frame throughout the entire working space of the working cylinder (hereinafter referred to as the "reverse moment"), providing each branch with an anti-gravity moment that varies approximately according to the sine law. This reduces or eliminates the moment (hereinafter referred to as the "gravity moment") due to the gravity of the working cylinder (which may include the weight of the piston rod) acting on the center of the UPS branch U-joint of the tilt joint support. A multi-degree-of-freedom parallel mechanism motion platform system with low side force or friction force is provided, as well as a motion platform with a small overall load and a motion system in which gravity load is appropriately compensated.

[0144] The side force reduction device is essentially a special two- or three-degree-of-freedom parallel mechanism (closed loop) or serially connected mechanism (open loop). It is characterized by applying an anti-gravity moment that varies according to the sine law to a universal joint-receiving actuation cylinder within a conical working space.

[0145] There are multiple side force reduction devices for parallel mechanisms that have multiple degrees of freedom and include UPS-like branches. Any of the side force reduction devices can be applied to any of the parallel mechanisms listed above. Therefore, there are a variety of application forms.

[0146] The technical aspects of the present invention will be described in detail below.

[0147] Example 1 As shown in Figure 1, there are structural types that are closed loop, have no support disk, and generate tension force directly using a single spring.

[0148] It includes a base frame 1, a force application device 2, a direction adaptation device 3, a universal swing rod device 4, and an integrated external connection device 5. The first four are called the functional structure body, and the remaining part is called the connection device. Since all forms of closed-loop embodiments include multiple parts as described above, they will not be described in detail in the following description.

[0149] 1. The base frame 1 is a rigid structural frame. Its lower part is a base mounting base 1A1.1 connected to the foundation, its upper part is an external connection device 1B1.3 connected to a direction adaptation device 3, and its middle part is a frame body 1.2 that bears force.

[0150] The base frame 1 functions to provide a mounting fulcrum for a direction adapting device, a force applying device, and the like.

[0151] 2. The force application device 2 includes a force generation device 2.2, a force transmission device 2.3, and external connection devices 2A2.1 and 2B2.4.

[0152] In this embodiment, the force generating device 2.2 is a tension spring 2.2a, and the force transmitting device 2.3 is a universal joint type transmission device 2.3d. The external connecting devices 2A2.1 and 2B2.4 of the force applying device are connected at one end to the cylinder body of the actuator by a universal joint, and at the other end to the direction adapting device 3.

[0153] The force applying device functions to apply an appropriate force or moment to the oscillating working cylinder. The tension spring may be a combination spring or a parallel connected spring, thus reducing the volume and length of the spring and increasing the energy density.

[0154] 3. The direction adaptation device 3 includes a universal joint (or universal pulley) and two external connection devices 3A3.1 and 3B3.4. The universal joint includes two swivel pairs, swivel pair A 3.2 and swivel pair B 3.3. In this embodiment, the two swivel pairs A and B are orthogonal but not flush (the distance between them is e2; if e2 is 0, they are orthogonal and flush) to form a universal joint. One end 3.1 of the external connection device of the direction adaptation device 3 is connected to the upper end of the base frame, and the other end 3.4 is connected to the force application device. The direction adaptation device 3 functions to provide a two-degree-of-freedom operating space for the force application device and the actuating cylinder to swing. The two swivel pairs of the universal joint work together to accommodate changes in the pitch angle and yaw angle of the actuating cylinder.

[0155] 4. Universal swing rod device The universal swing rod device 4 includes a universal joint (or spherical joint) 4.2, a connecting rod 4.3, and external connecting devices 4A4.1 and 4B4.4. The universal joint is connected to the connecting rod, and the connecting rod device may be replaced by the body of the actuating cylinder (similarly in each embodiment). The connecting rod (or cylinder body) is provided with a rotating pair mounting base, and the size of R1 (see Figure 1 for R1) can be changed by adjusting the position (A1a) of the mounting base on the connecting rod. Various connecting rods are available; see Examples 1, 2, 9, and 14. In the figures, 4.4b is a piston rod, a type of external connecting device. The universal swing rod device 4 is connected to the base platform or the force application device, provides the working cylinder with a two-degree-of-freedom (or three-degree-of-freedom) working space, and serves as an integral part of the parallel mechanism. Universal joint types include, but are not limited to, RR, U, RU, UR, RUR, S, and the like.

[0156] 5. The integrated external connection device includes a connection device 5A5.1 of the base frame and a connection 5B5.2 for connecting the force application device to the cylinder barrel or piston rod. Function: Fix the whole device and connect the task load, i.e. connect to the working cylinder or piston rod. Integrate with the working cylinder or parallel mechanism. The base frame 1, force application device 2, direction adaptation device 3, and universal joint swing rod device 4 form a closed loop (the base is the large member), and each member cooperates with the other to enable synchronized movement of each member and to apply appropriate anti-gravity moment and weight compensation. When applied to a 6-UPS parallel mechanism, such a closed loop mechanism is required for each branch. This closed loop is a special two-degree-of-freedom parallel mechanism whose motion platform is a swinging connecting rod. The mechanism is characterized by canceling or partially canceling the moment due to gravity acting on the connecting rod and / or by offsetting the weight of some or more actuating cylinders or moving platforms.

[0157] In the figure, A1a is the design connection point between the force application device and the working cylinder, and A2a is the design connection point between the force application device and the direction adaptation device.

[0158] For symbols not explained, please refer to the symbol explanation.

[0159] Below, some problems related to the embodiment are explained.

[0160] The parallel mechanism in this specification is a parallel mechanism with 2 to 6 degrees of freedom, at least one of which is a UPS-type branch.

[0161] Figure 1.1 is a schematic diagram of a 6-UPS type 6-DOF parallel mechanism. Six UPS branches 7.3 are connected to a base platform 7.2, and the connection points form a hexagon, with the interior of the hexagon as the inside. The upper ends of the six UPS branches 7.3 are connected to a kinematic platform 7.4.

[0162] The universal joint connected to the base platform is called the base platform universal joint 7.3a, and since it is the base platform universal joint that is most commonly used in this specification, it is usually simply called a universal joint (to avoid confusion, the connecting device for the direction adapting device or force applying device is called a universal joint).

[0163] In branch 7.3, the universal joint connected to the motion platform is called the motion platform universal joint and is usually hexagonal in shape with connection points (it can also be triangular, quadrangular or pentagonal).

[0164] The space enclosed by the two hexagons and the six branches is the inside, and the corresponding outside is the outside.

[0165] The outside of a particular universal joint is not the outside of another universal joint, but is proximate to that universal joint.

[0166] The mounting of the foundation device usually refers to the inside or outside of the plane of the foundation platform.

[0167] One of the working spaces of the working cylinder and the branching working cylinder (leading pair, cylindrical pair, or screw pair) is the pitch working space, which is usually in the range of 0 to 90 degrees (see Figure 1.2), and the other is the yaw working space, which is about 110 degrees (see Figure 1.3). The working space is determined by several parameters of the motion platform, and different structures result in different working space parameters.

[0168] Creating a coordinate system In creating the coordinate system, the horizontal plane is the xy plane. The upward direction is the positive direction of the Z axis, and the origin is the center of the first turning pair of the UPS branch.

[0169] Figure 1.2 is a side view of the schematic diagram of the gravity moment force-receiving principle of the tilted joint-supported working cylinder. L1 is the initial position of the axis of the working cylinder, where the pitch angle is the minimum, and L3 is the axis of the working cylinder at the maximum pitch angle. The difference between the two angles is the pitch operating range αm of the working cylinder. A gravity force G0 acts on or near the axis of the working cylinder, and this gravity forms a gravity moment with respect to point O, the coordinate origin. This gravity moment forms an additional positive pressure on the piston and cylinder head, and this positive pressure is called the side force.

[0170] A1 is a theoretical connection point between the force application device and the cylinder body, and A2 is another theoretical connection point of the force application device (connection point with the direction adaptation device). The tension spring applies a force to the operating cylinder, and one component of this force forms a moment called the anti-gravity moment with respect to point O (the horizontal axis), and when the gravity moment and the anti-gravity moment cancel out or nearly cancel out, the positive pressure acting on the cylinder body and piston is smallest or relatively small.

[0171] The distance between the vertical line passing through point A2 and the vertical axis of the coordinate system is called the eccentricity e1. When this eccentricity e1 is 0, that is, when A2 is on the Z axis, the balance error of the antigravity moment is the smallest, and when the eccentricity e1 is large, several branch balance errors will occur.

[0172] The law of change of the gravitational moment is that the greater the angle between the axis of the working cylinder and the vertical axis, the greater the gravitational moment. When the angle reaches 90 degrees, the gravitational moment is greatest, and between these angles it follows a sine law or approximately a sine law, as shown in Figure 10.3. The curve in Figure 10.3 is a sine curve.

[0173] Figure 1.3 is a top view showing the yaw range of the actuating cylinder. Since the eccentricity e1 is not zero, the antigravity moment forms an acting moment about the z-axis with respect to point O (it is clear that this moment is zero when the eccentricity is zero). The larger the eccentricity, the larger this moment becomes. This moment is undesirable. The smaller the moment, the more favorable it is. The dynamic analysis should take into account the effect of this moment on the motion of the motion platform. This eccentricity also affects the antigravity moment and also causes an error (although it is very small).

[0174] In Figures 1.2 and 1.3, F0 is the spring force, F1 is the projection of F0 on the axis of the working cylinder, F2 is the projection of F0 in a direction perpendicular to the axis of the working cylinder (in the plane of F0 and F1), and F3 is the projection of F0 in a direction perpendicular to F0 and F1.

[0175] If a support disk is present, the situation shown in Figure 1.3 does not exist, and in this case, when viewed from the top, point D2 is on the extension of the axis of the working cylinder, meaning that there is no acting moment (F3 = 0) centered on the z-axis. This is an advantage of the configuration with a support disk, but the disadvantage of the configuration with a support disk is that it has large rotational inertia.

[0176] Figure 1.4 shows a cross-sectional view of a working cylinder, showing the relative dimensions of the working cylinder and the range of motion of the piston rod, where Lmin is the position where the piston displacement is zero, which is usually the position where the positive pressure is smallest.

[0177] Lmax is the position where the piston displacement is at its maximum, which is usually the maximum positive pressure.

[0178] Lx is the distance between the piston position and the center of the universal joint. When Lx=Lmin+0.5(Lmax-Lmin), it is called the neutral position of the piston or the neutral position of the working cylinder. The gravity moment at the piston neutral position may also be called the anti-gravity moment design point.

[0179] L0 is the minimum distance between the center of the base platform universal joint and the center of the motion platform universal joint of one branch.

[0180] Structure of the connecting device between the force applying device and the operating cylinder (see Figures 1.5 to 1.9)

[0181] Figure 1.5 shows an external connection device 2.4 with two rotational degrees of freedom, and Figure 1.6 shows an external connection device 2.4 with three rotational degrees of freedom. This is a hollow universal joint of the universal joint type 2.4a. The connecting pipe 2.4d is connected to the cylinder body. 2.4i is a U-shaped fork. 2.4e is a hollow cross shaft. 2.4b is a hook and ring type external connection device.

[0182] The connecting pipe 2.4d in Figure 1.5 is connected to a hollow universal joint, and the other end of the connecting pipe 2.4d in Figure 1.6 is connected to a hollow three-axis orthogonal spherical hinge.

[0183] Figures 1.5 and 1.6 show hollow universal joints. The hollow shaft rotating pair accommodates the rotation of the actuating cylinder, and another rotating pair of the hollow universal joint accommodates the change in direction of the force applying device. There are two force applying devices, one on each side of the actuating cylinder. By placing springs (including combination springs) on both sides, the length of the springs is reduced (when not tensioned). One end of the force applying device is connected to the actuating cylinder connecting rod device 2.3.

[0184] Figure 1.7 shows another connecting device. The external connecting device 2.4 is connected to the cylinder body 4.3d with bolts and fixed to the connecting rod. The intermediate cylinder body 4.3d is fixedly connected to the connecting pipe (plate) 2.4d. The connecting pipe (plate) 2.4d is connected to the universal joints 2.4a and the hook-and-ring universal joint 4b. The two rings movably connected to each other form a universal joint.

[0185] Figure 1.8 shows the flexible external connection device 2.4. Two coaxial shafts are fixedly connected to both sides of the cylinder body 2.4d, and two hook rings 2.4b are connected to the shafts. A hook is placed at the end of one cable 2.4f, and the hook is connected to two links, forming an inverted V shape. The cable and pulley 2.4b work together, and the pulley is connected to the cable, which moves within the groove. The pulley moving on the cable forms a flexible rotating pair that rotates around the axis of the operating cylinder. In this way, a spherical hinge function is obtained.

[0186] Figure 1.9 shows another external connection device 2.4 of the hook and ring type. The connecting pipe (plate) 2.4d is fixedly connected to the cylinder body 4.3d with bolts. A hook and ring is placed above the connecting pipe (plate) 2.4d, forming the hook and ring type 2.4b, universal joint type 2.4a, and external connection device (spherical hinge type).

[0187] Figure 1.10 shows a spherical hinge with four orthogonal axes, where the axis of the first turning pair 4.2a is perpendicular to the ground and the axis of the fourth turning pair 4.2d overlaps with the axis of the cylinder body. The axes of the second and third turning pairs are orthogonal and may or may not be flush with each other, resulting in universal joint 4.2e. This is a symmetrical four-axis orthogonal spherical joint. If the first turning pair or the fourth turning pair is omitted, it becomes a three-axis orthogonal spherical joint.

[0188] Types of universal joints (used in swivel connecting rods) The universal joint types include, but are not limited to, RR, U, RU, UR, RUR, and S. RUR is a symmetric orthogonal spherical hinge (see Figure 1.10) in which the axis of the first revolving pair R is perpendicular to the plane of the base platform and the axes of the remaining revolving pairs R are coincident with the axis of the working cylinder. In the RU universal spherical hinge, the axis of the first revolving pair R is perpendicular to the plane of the base platform and the axes of the revolving pairs R after the UR spherical hinge are coincident with the axis of the working cylinder. The axes of the two swivel pairs of the universal joint are generally perpendicular, and perpendicular (non-flush or flush) is the optimum configuration. Theoretically, it is fine as long as they are not parallel. For this reason, in the present invention, there are cases where they are not parallel.

[0189] Gravity moment design point selection Gravitational moment: Maximum gravitational moment Mmax, minimum gravitational moment Mmin, cylinder body weight force moment Ma,

[0190] The gravity moment is the gravity moment that the weight of the working cylinder and any additional weight exert on point O (the center or horizontal axis of the universal joint). The gravity moment is variable due to the movement of the piston rod.

[0191] Generally, the center of gravity of the actuating cylinder is on the axis of the actuating cylinder, and in this case, the gravity moment varies according to a sinusoidal law depending on the pitch angle. However, in some cases, the center of gravity deviates from the axis. For example, there is an electric cylinder in which the motor is not directly connected to the cylinder body (in an H-type or L-type connected electric cylinder, the motor is located on one side of the cylinder body). In this case, the change in the gravity moment depending on the pitch angle deviates from a sinusoidal curve (if required, the zero-action force point of the force application device can be adjusted, for example, so that the anti-gravity moment is zero at the maximum pitch angle).

[0192] The weight of the entire branch does not become the gravitational moment.

[0193] Maximum angular gravitational moment M: When the axis of the actuating cylinder is perpendicular to the ground or forms a small angle with it, the gravitational moment is 0, which is the maximum angular gravitational moment. The force exerted by the force-applying device at or near that point is 0. If prestressed, it may be nearly 0.

[0194] Minimum angular gravity moment M: When the axis of the working cylinder is horizontal, the gravity moment is the largest and is called the minimum angular gravity moment. When the axis of the working cylinder is at the minimum pitch angle, it is called the minimum pitch angle gravity moment.

[0195] Cylinder body weight force moment Ma: This is the gravitational moment that the weight of the cylinder body of the working cylinder exerts on point O, and is called the cylinder body weight force moment Ma. When the axis of the working cylinder is horizontal, the gravitational moment due to the weight of the cylinder body is called the cylinder body maximum gravitational moment.

[0196] Gravitational moment of working cylinder piston maximum displacement: When the working cylinder is extended to its maximum length (Lx = Lmax), the gravitational moment that the weight of the working cylinder exerts on point O is called the gravitational moment of working cylinder piston maximum displacement. When the axis of the working cylinder is horizontal, the gravitational moment is the largest and is called the maximum gravitational moment of longest displacement Mm.

[0197] Non-displacement gravity moment: When Lx = Lmin, the gravity moment that the weight of the working cylinder exerts on point O is called the non-displacement gravity moment. When the axis of the working cylinder is horizontal, the non-displacement gravity moment is the largest and is called the maximum non-displacement gravity moment Ms. G1: The weight of the cylinder body of the working cylinder that exerts a gravitational moment on O (does not include the weight of the material to the left of point O in Figure 1.4 and the weight offset by the weight of this part). G2: Weight of the piston rod (does not include the weight of the material to the right of point O in Figure 1.4 and the weight offset by this part.) R0: When the displacement of the piston rod is 0 (when Lx = Lmin), the distance from the center of gravity of the working cylinder to the joint receiving point of the working cylinder. If the antigravity moment design point Ms is between 80%Mmax and 120%Mmax, the accuracy of positive pressure cancellation and weight compensation performance will be excellent. For example, Ms = 90%Mmax (positive pressure is minimum and weight compensation is slightly small), or Ms = 110%Mmax (positive pressure is slightly large and weight compensation is large). Or Ms = 0.5 (Mmax ​​+ Mmin), or Ms = Ma, etc. From an engineering perspective, an error of ±3% or slightly larger is permitted.

[0198] When the antigravity moment design point is at the piston neutral position, if the piston displacement is 0, the antigravity moment is relatively large.

[0199] When the piston displacement is greatest, the antigravity moment is relatively small and positive pressure remains. If the antigravity moment design point is properly selected, the positive pressure remaining at both ends will be equal or nearly equal when the piston is at both ends. This is a characteristic of the optimal design point. The optimal design point is obtained when the antigravity moment design point is within a small region of the piston neutral position.

[0200] Spring stiffness, spring deformation Ls, gravitational moment design point (i.e., the amount of gravitational moment to be resolved) The deformation amount of the spring is related to the pitch working space and the connection end positions A1a and e1. The distance between the universal joint center O and the connection point A1a is the actual moment arm length R1 of the anti-gravity moment, and the distance from the horizontal axis connection point (or the intersection of the cross axes) of the force application device and the direction adaptation device to the universal joint center O is R2. R1 and R2 are approximately equal. The maximum distance between the two connection end points is Ls. Ls is the deformation amount of the force application device. The actual deformation length is slightly larger than Ls.

[0201] When the working cylinder is horizontal, the force applying device meets the design requirements and can sufficiently counteract the gravity moment (meeting the design requirements). When the working cylinder is vertical, the anti-gravity moment of the force applying device is 0 or nearly 0.

[0202] The eccentricity e1 (see Figures 1, 2, etc.) is the distance between the vertical axis of the direction adaptor (or the vertical line passing through the horizontal axis connection point) and the vertical line passing through the center of the universal joint. e1 is equal to or greater than 0. If the pitch working space of the actuating cylinder is small, e1 may be 0.

[0203] Effect of eccentricity: When the eccentricity is greater than 0, a large effective working space is given to the force applying device, but the force applying device generates a moment of rotation about the vertical axis with respect to the working cylinder. The larger the eccentricity, the larger the moment of rotation about the vertical axis. This moment must be taken into account in the dynamic analysis (see F3 in Figure 1.3). In the configuration with slewing bearings, this force F3 does not exist.

[0204] Working process of embodiment 1: When the actuating cylinder performs pitch change, as the pitch angle decreases, the cable length increases, the tension force of the tension spring increases, and the anti-gravity moment increases. On the other hand, as the pitch angle increases, the anti-gravity moment decreases. The change follows the sine law or approximately the sine law. When the actuating cylinder performs yaw movement and the pitch angle does not change, the cable length remains constant and the anti-gravity moment remains unchanged or changes within an error. Under the action of the actuating cylinder, the tension spring performs yaw movement following the actuating cylinder, causing the direction adaptation device to rotate around the vertical axis. The working processes of other embodiments are similar to this embodiment, and therefore will not be described in detail here unless otherwise specified.

[0205] Example 2 As shown in Figures 2, 2.1, 2.2, 2.3, and 2.4, the structure of Example 2 is a closed loop with no support disk, tension springs on both sides, and the upper end of the cable spring is mounted in the spring mounting bush 2.2h.

[0206] Compared with Example 1, Example 2 differs in the following two points: First, the base frame 1 is a size-adjustable rigid structural frame, and second, some changes are made to the force application device. The overall structure is similar to Example 1.

[0207] The base frame 1 is a size-adjustable rigid structural frame, with the base mounting base 1.1 at its bottom, the external connection device 1.3 at its top, and the force-bearing frame body 1.2 in the middle. The base frame 1 provides suitable mounting points for the direction adaptation device and the force application device. The frame body 1.2 is adjustable in two dimensions, top and bottom, and left and right (height and width), and after adjustment, it is fixed back into place to form a rigid frame. This adjustment allows it to accommodate parallel mechanisms of various structures and sizes.

[0208] The force generating device 2.2 of the force applying device 2 is two sets of tension springs 2.2a arranged on both sides (top view) of the actuating cylinder, and the force transmitting device 2.3 is a spring bearing 2.3d to which a spherical hinge is connected. The external connecting device 2.1 has one end connected to the direction adapting device and the other end 2.4d connected to the connecting rod 4.3a.

[0209] Figure 2.1 shows a combination of a force application device (part) and a direction adaptation device, in which one end of the cable spring is fixedly connected to the inside of a cylinder, and when the spring is free, the whole or most of it is inside the cylinder. The connecting axis of the cylinder and the horizontal axis of the force generation device is located at the fixed end of the cylinder, away from the spring. The spring (or most of the cylinder) is located outside the pitch working space of the working cylinder, thereby increasing the working space for the working cylinder. e1 is usually small (e.g., less than 10% of the working cylinder length) or 0 (similarly for e2 and e3).

[0210] Figure 2.2 shows a combination of a force applying device consisting of two pocket coils, a direction adapting device, and a cylinder. The horizontal axes of the direction adapting device are on either side of the vertical axis, and two U-shaped forks are connected to each pocket coil. One end connected to the actuating cylinder is connected to the rod of the connecting tube by a universal joint. The connecting rod is connected to the cylinder via a swivel pair.

[0211] The spring of the force applying device is mounted at the bottom in the spring mounting bush, which is also advantageous for synchronous movement. The spring mounting bush 2.2f is connected to the direction adapting device 3 or the actuating cylinder as a force transmitting device. The spring mounting bush is rotatable around the horizontal axis 3.3 of the direction adapting device 3. The undeformed spring is housed in a spring packet, most of which is outside the pitch working space. The other end of the force applying device is connected to the actuating cylinder or the actuating cylinder connecting rod.

[0212] The springs on both sides can be a combination spring or a four-spring packet on each side, which can further reduce the spring length, increase the pitch working space, and reduce the eccentricity e1.

[0213] 3. The direction adaptor 3 includes an eccentric universal joint and two end connectors 3A and 3B. The axis of one swivel joint 3.2c is perpendicular to the ground, while the axis of the other swivel joint 3.3c is horizontal. The two swivel joints are perpendicular to each other and non-coplanar. The distance between the axes of the two swivel joints is e2, known as the eccentricity e2. The output end of the horizontal swivel joint has two U-shaped frames, each of which is fitted with a spring mounting bush 2.2h. The axes of these swivel joints are horizontal, forming one swivel joint 3.3 of the direction adaptor. Normally, the moment exerted by the springs on both sides on the vertical axis swivel joint is the same; however, different tension forces on both sides result in different moment arms. The opening of the spring mounting bush is trumpet-shaped.

[0214] 4. Universal swing rod device The universal swing rod device includes a universal joint (or spherical joint) 4.2, a connecting rod 4.3a, and external connecting devices 4A4.1 and 4B4.4a. The universal joint is connected to the connecting rod, and the connecting rod device (Fig. 2.3) has two spherical hinge mounting bases for connecting force applying devices.

[0215] The size of R1 (see Example 1 and FIG. 1 for R1) can be changed by adjusting the position of the mounting base on the connecting rod. Various connecting rods are available, see Examples 1, 2, 8, and 14.

[0216] It is connected to the base platform, the force application device, and the actuating cylinder, and provides a two-degree-of-freedom (or three-degree-of-freedom) working space for the actuating cylinder to swing, thereby functioning as an integrated part of the parallel mechanism.

[0217] Figure 2.3 shows one of the structures of the connecting rod with connecting bases, in which the right connecting base is connected to the universal joint and the left connecting base is connected to the tubular spring.

[0218] An actuating cylinder may be used in place of the actuating cylinder connecting rod arrangement (as in any closed loop embodiment). The connecting rod is provided with a swivel mounting base, and the magnitude of R1 can be changed by adjusting the position of the mounting base on the connecting rod.

[0219] 5. The integrated external connection device includes a base frame connection device 5A and a connection device 5B with the cylinder body or piston rod. Similar to the first embodiment.

[0220] Mounting: The base is mounted on the outside of the universal joint (see the definitions above for outside and inside). The connection point between the force application device and the frame is located above the universal joint. If there is eccentricity in the two springs on the left and right, a revolving pair that rotates around the actuating cylinder is used as the connection device. If the eccentricity is small, the deformation of the spring itself also meets the requirements. Due to the existence of eccentricity, the planes of the two springs may be twisted. However, this torsion is small and does not affect use.

[0221] For determining the spring stiffness and the mounting size, refer to Example 1.

[0222] Improvement 1 of Example 2 To increase the pitch operating space for the actuating cylinder, a spring packet is provided at each end of each set of springs. A combined spring is used as the spring. The eccentricity is small. When the pitch angle is maximum, all the springs can be located within the spring packets at both ends.

[0223] Improvement 2 of Example 2 Based on Example 2, the force application device is a series connection of a tension spring and a cable. The two springs together constitute the force application device. As shown in Figure 2.4, one cable is provided on one side of the two springs, and the cable is connected to the connecting shaft, thereby forming a flexible turning pair.

[0224] Figure 2.4 is a schematic diagram of the flexible swivel 3.3a of the direction adaptation device 3. The flexible swivel is used instead of the horizontal swivel 3.3 of the direction adaptation device 3. The horizontal swivel is a partial sheave fixed to the vertical axis and, in combination with the cable, forms a flexible swivel that responds to changes in the pitch angle.

[0225] The changes in the direction adaptation device are as follows: The horizontal axis rotating joint of the direction adaptation device is changed to a flexible rotating joint 3.3a. The horizontal axis is composed of both a slotted fixed wheel and a cable 2.3a. The slotted fixed wheel 3.3a has a horizontal axis and is fixed to the output end of the vertical shaft. The cable is fixed to the wheel through the slot. The cable may be wound inside the slot and move. This results in a flexible rotating joint. The connection between the force application device and the operating cylinder also becomes a connection between a cable and a pulley, resulting in a flexible moving joint.

[0226] For the rest, see Example 2. For determining the spring stiffness and mounting size, see Example 1.

[0227] Example 3 Figures 3, 3.1 and 3.2 show closed loop configurations with no slewing bearings, no cable deflection and torsion spring tension.

[0228] In Example 3, compared to Example 1, only the force application device 2 is changed. The force generation device 2.2b of the force application device is changed to a torsion spring, which generates a tensile force. A cable unit is used as the force transmission device 2.3a. The torsion spring is attached above the universal joint and connected to the connecting rod via a cable. One end of the cable of the force transmission device is connected to the torsion spring, and the other end is connected to the actuating cylinder connecting rod 4.3a via a connecting device 2.4a. The horizontal axis of the direction adaptation device overlaps with the axis of the torsion spring, and both share the same revolute pair.

[0229] The torsion spring is attached to a horizontal axis above the direction adapting device 3, and the rotation of the torsion spring generates a tension force. As shown in Figures 3.1 and 3.2, the torsion spring rotates following the vertical axis of the direction adapting device, adapting to the yaw movement of the actuating cylinder. There are various structural forms of the torsion spring. The force adjusting device 2.5 can change the degree of tension in the cable to change the magnitude of the pre-tension force. Generally, the pre-tension force is zero or nearly zero. The pre-tension force corresponds to the axis of the actuating cylinder being vertical or nearly vertical.

[0230] The connection position between the connection base and the swing rod is adjustable, i.e., the distance between A1a and the universal joint is variable.

[0231] Torsion springs come in a variety of structures, including single torsion springs, multi-torsion springs, and combination torsion springs (two torsion springs of different diameters nested together). Figures 3.1 and 3.2 show two types of torsion spring structures.

[0232] Figure 3.1 is a schematic diagram of a torsion spring force generator. Two torsion springs 2.2b are arranged symmetrically, and the torsion springs are wound around a fixed shaft 2.2l, which is fixed to a torsion spring mounting base 2.2f or foundation. One end of the torsion spring is fixed to the base, and the other end is connected to a rotating cylinder 2.3i. The axes of the fixed shaft and the cylinder overlap, and the cylinder can rotate around the fixed axis, thereby forming a rotating pair. Figure 3.2 uses one torsion spring. Otherwise, it is the same as Figure 3.1.

[0233] A cable is wound around one end of the rotating cylinder. The cable is wound around the rotating cylinder. When the cable is pulled, the rotating cylinder rotates, twisting the torsion spring and generating tension. The cable passes through the hollow shaft of the directional adaptor, over a sheave, and is connected to the actuating cylinder.

[0234] The force transmission device includes a cylinder and a cable. The cylinder is fitted to the outer surface of the fixed shaft. The two cylinders are rotatable around the same axis. The outer cylinder is rotatable around the axis of the fixed shaft. The cylinder overlaps the axis of the horizontal axis of the direction adaptation device, and the cylinder is fixed to the horizontal axis of the direction adaptation device. One end of the torsion spring is fixed to the fixed cylinder or base, and the other end of the torsion spring is fixed to the rotating cylinder. When the rotating cylinder rotates, the torsion spring twists in conjunction with the rotation. A cable is connected to the rotating cylinder. The cable is wound around the rotating cylinder. When the cable is pulled, the torsion spring rotates and a tensile force is generated. The force generation device is located outside the pitch working space, which is advantageous for branch operation.

[0235] During operation of Example 3, when the actuating cylinder undergoes pitch change and the pitch angle decreases, the cable length increases, the tension of the torsion spring increases, and the anti-gravity moment generated by the torsion spring increases. On the other hand, when the pitch angle increases, the anti-gravity moment decreases. When the actuating cylinder performs yaw movement and the pitch angle does not change, the cable length remains constant, the anti-gravity moment remains constant or changes within an error, and the torsion spring performs yaw movement following the actuating cylinder due to the action of the cable (the cable rotates around the vertical axis of the direction adaptation device).

[0236] Example 4 As shown in FIG. 4, based on the third embodiment, after the pulley changes the direction of the cable, the force applying device is attached to the bottom or foundation of the base frame.

[0237] 1. The base frame 1 is a rigid structural frame, with the lower part being the external connection device 1A1.1 and the upper part being the external connection device 1B1.3, used to mount the direction adapting device. The frame body is a length-adjustable member 1.2a. The base frame is almost the same as in Example 2.

[0238] 2. The force generating device 2.2 of the force applying device 2 is a tension spring 2.2a, and the force transmitting device 2.3 is a cable device 2.3a. One end of the force applying device's cable 2.3a is connected to the cylinder body of the actuator, and the other end is connected to the bottom of the base frame after being changed in direction by the pulley of the direction adapting device 3. The direction adapting device 3 is located above the universal joint. The cable is connected to the actuating cylinder through the groove of the pulley of the direction adapting device 3. The pulley determines the direction of the first section of the cable in the pulley, which is called the second section. The axis of the second section of the cable is perpendicular to the ground (with an error of approximately 10° allowed). To meet operating space requirements, the force generating device may be mounted below the ground. In the figure, the spring is mounted in a spring packet, which facilitates its installation. The spring packet is mounted below the base frame. The second section of the cable is rotatable around its own axis. The yaw motion of the actuating cylinder is blocked. In Figure 4, R1 and R2 are equal (ignoring the slight changes in R2). A2a is on the arc of the horizontal axis pulley. To facilitate preloading of the force application device or initial force variation of the force application device, an adjustment device is provided, in this example the gasket 2.5 is used as the adjustment device.

[0239] 3. The direction adaptor is a universal pulley with eccentricity e3. The axis of the swivel A3.2 of the direction adaptor is approximately perpendicular to the ground (allowing for an error of approximately 10°) and is used to adjust the yaw angle. The axis of the other swivel B3.3 is parallel to the ground (located below the other swivel) and is used to adjust the pitch angle. A slotted pulley is attached to the horizontal shaft. That is, the horizontal swivel of the direction adaptor is a pulley. The cable changes direction via the pulley. During operation, the actuating cylinder performs yaw oscillation, the pulley oscillates, and the second section of the cable rotates around its own axis in conjunction with the oscillation. The axis of the second section of the cable and the axis of the vertical shaft of the direction adaptor are approximately overlapping. The direction adaptation device is provided with connection devices, one of which is connected to the base frame and the other of which is connected to the force application device.

[0240] 4. For the universal swing rod device (shown in dashed lines in Figure 3), see Example 1. The universal swing rod arrangement 4 includes a cylinder barrel 4.3d of the actuating cylinder and a universal joint 4.2e. In this example, the cylinder barrel of the actuating cylinder is replaced by a connecting rod arrangement. In Fig. 4, the dashed lines are removed to obtain an open loop embodiment.

[0241] 5. The external connection device 5.1 is attached to the ground foundation platform as a whole, and 5.2 is connected to the platform or piston rod (task load).

[0242] Below we discuss some design issues.

[0243] Regarding R1 and R2, the R2 moment arm is different from that in Example 1. Since A2a is on the arc of the pulley, the intersection point between the cable and the arc changes depending on the pitch angle. The change is small and can be ignored.

[0244] Let R1 be the distance between the center O of the universal joint and the connection point A1a where the actuator connects, and R2 be the distance between the horizontal shaft pulley of the direction adaptor and the first stage contact point A2a of the cable. R1 and R2 are approximately equal. The maximum distance between A1a and A2a is the maximum deformation of the tension spring. A1a is at the top of the actuating cylinder. There will be a small error, but it is within the allowable range.

[0245] For the selection of the gravity moment as the design point, see Example 1. For the spring stiffness and spring deformation, see Example 1. In this example, the gravity moment when the piston is neutral is selected as the design point.

[0246] The axis of the vertical shaft of the direction adaptor and the axis of the second section of cable substantially overlap. Eccentricity e2: the distance between the vertical line passing through the connection point (definition given) of the horizontal axis of the directional adaptation device and the vertical line passing through the center of the universal joint. e2 is greater than or equal to 0.

[0247] Effect of eccentricity e1: Generally, the pitch angle working space of the working cylinder is between 70 and 80 degrees. A force application device must be installed on the sector surface of this space, and since the force application device has a certain length, the working space of the working cylinder is occupied. Eccentricity exceeding 0 increases the effective working space of the working cylinder.

[0248] Example 5 As shown in FIG. 5, Example 5 is almost the same as Example 4, but the main difference is that the force generating device of the force applying device is changed to a torsion spring, and the tension force is generated by the torsion spring, and appropriate adjustment is made to the direction adapting device.

[0249] 1. The base frame is almost the same as in Example 4, so it will not be described in detail here.

[0250] 2. The force application device includes two parts: a force generation device and a force transmission device. The force generation device generates tension using a torsion spring, and the force transmission device is the same as in Example 4, transmitting power via a cable. The torsion spring is attached below the universal joint (direction adaptor). The axis of the second stage of the cable is perpendicular to the horizontal plane (appropriate tolerances are allowed).

[0251] 3. For the torsion spring structure, refer to Figures 3.1, 3.2, and Example 3. The direction adaptor 3 is similar to that of Example 4, except that the vertical axis is hollow and located below the horizontal axis, and the cable passes through the center of the hollow shaft. The pulley ring has a slot, and the cable is wound around the slot of the ring. The radius of the cable wound around the pulley is equal to or approximately equal to e2. When the pulley swings, the hollow shaft rotates synchronously, which is used to accommodate the yaw angle. The second section of the cable (the segment connected to the force application device) is always within the hole of the hollow shaft. When the actuating cylinder swings, the pulley swings in conjunction with the swing, and the second section of the cable twists, thereby blocking the swing of the actuating cylinder. The torsion spring has only one rotational degree of freedom.

[0252] 4. The universal swing rod device 4 uses a non-coplanar orthogonal universal joint, the first turning pair axis of which is perpendicular to the horizontal plane. It has two centers with an eccentricity e3 and a large pitch space. The connecting rod 4.3 is for a cylinder body. The stiffness of the torsion spring is determined by parameters such as tension and radius of the torsion spring. For determining the stiffness of the spring and the installation size, refer to Example 1.

[0253] Improvement 1 of Example 5 When torsion springs are installed on both sides, they take up a large amount of space, causing interference when installing two adjacent UPS branches. Therefore, two springs can be placed on the same side. One of the two springs has a large diameter and the other has a small diameter. The smaller spring is made longer and the two are nested. One end of each of the two torsion springs is fixed to the base and the other end is fixed to the rotating cylinder. The cable remains single. In this way, there is no torsion spring on the other side, and no disturbance space is required. Two adjacent UPS branches can be installed adjacent to each other.

[0254] Working process of Example 5 In the operating process of Example 5, when the actuating cylinder undergoes pitch change and the pitch angle decreases, the cable length increases, the torsion spring rotates, the tension force increases, and the anti-gravity moment generated by the torsion spring increases. On the other hand, when the pitch angle increases, the anti-gravity moment decreases. When the actuating cylinder performs yaw movement and the pitch angle does not change, the cable length remains constant and the anti-gravity moment remains constant or changes within an error range. The actuating cylinder performs yaw swing, causing the first fixed cable to swing and the second section of the cable to rotate around its own axis, blocking the swing of the actuating cylinder. Therefore, the torsion spring is fixed to the base frame or the ground and does not swing along with the actuating cylinder.

[0255] Example 6 As shown in Figure 6, this embodiment is a closed loop type with no support disk and uses a standard tension spring to change the cable direction twice. Compared to Example 4, the cable direction is changed twice and the tension spring is attached with its axis horizontal, but the rest is similar to Example 4.

[0256] 1. The base frame is similar to that of Example 4, except that a direction-changing pulley (or pulley group) is attached to the bottom, and a protective cover is also attached, and a protective cover is also attached to the direction-adapting device on the top.

[0257] 2. A pulley 2.3e (or pulley group) is added to the bottom of the force application device. The cable undergoes a second direction change by pulley 2.3e. This pulley (or pulley group) changes the cable's direction a second time. The cable's direction is changed by the horizontal axis pulley of the direction adaptation device, becoming the second section of cable. The axis of the second section of cable (between pulley 2.3e and the horizontal axis pulley of the direction adaptation device) is perpendicular to the horizontal plane. The cable that has undergone a second direction change has a selective direction. This makes it even easier to attach a cable spring. In this example, the force generation device of the force application device is attached to a base platform. The force applying device is connected to the connecting rod by a hollow spherical hinge (see Figure 1.6), and the cylinder of the working cylinder passes through the inside of a hollow cross shaft and is attached to the connecting base. The hollow spherical hinge has a hollow cross shaft, and three axes are perpendicular to each other. The hollow axis rotational joint of the hollow spherical hinge corresponds to the rotation of the working cylinder, and the other rotational joint of the hollow spherical hinge corresponds to the change in direction of the force applying device.

[0258] 3. Directional Adaptation Device The direction adaptation device is mounted above the base frame and located directly above the universal joint (eccentricity is possible), with one axis perpendicular to the horizontal plane and the other horizontal, the horizontal axis located below the vertical axis, to which a slotted pulley is attached, and the cable passes through the slot of the pulley to change direction. The horizontal and vertical axes are perpendicular but not flush. The axis of the vertical axis of the direction adaptation device and the axis of the second section of the cable overlap or nearly overlap. The actuating cylinder drives the cable to perform yaw oscillation, and the cable drives the pulley to rotate around the vertical axis of the direction adaptation device. The second section of the cable rotates around its own axis without oscillating, thereby blocking the yaw oscillation of the actuating cylinder and converting the pitch oscillation into linear movement of the cable.

[0259] 4. Universal joint receiving swing rod device (universal joint types include, but are not limited to, RR, U, RU, UR, RUR, and S) The universal joint-supported swing rod device includes a universal joint 4.2 (the axis of the first turning pair is parallel to the horizontal plane), a connecting rod 4.3, a connecting device 4A4.1, a connecting rod device 4B4.4, etc. The universal joint 4.2 is fixedly connected to the connecting rod 4.3, and the cylinder block of the actuating cylinder may be used instead of the connecting rod device (as in any closed-loop embodiment). The connecting rod (or cylinder body) has a connecting base, and the magnitude of R1 (see Figure 1.1) can be changed by adjusting the position of the connecting base on the connecting rod. The universal joint-supported swing rod device is connected to the actuating cylinder, provides a two-degree-of-freedom working space for the actuating cylinder, and functions as an integral part of the parallel mechanism.

[0260] 5. The external connection device is generally similar to that of Example 4, and will not be described in detail here.

[0261] Improvement 1 of Example 6 In Example 6, a gearbox is added to the force transmission device. Figure 6.1 is a top view of the tension spring and gearbox. A gearbox 2.8 is added to the force application device to change the spring's output displacement, increase the small displacement, and shorten the spring's length. In Figure 6.1, the force transmission device and force initializing device are mounted on the transmission mounting base 2.2m. On the right side, a gearbox 2.8 is provided, which includes one large sheave 2.8a and one small sheave 2.8b. The two sheaves are fixedly connected together with their axes overlapping. The two sheaves are supported by the gearbox case 2.8e. One end of the tension spring 2.2a is connected to a cable, which is wound around the small sheave and fixed to cable connector A 2.8f. Another cable 2.8c is wound around the large sheave. One end of the cable is fixed to cable connector B 2.8g, and the other end connects the direction adaptor to the actuating cylinder. This force applying device allows for a larger stroke of the cable in the spring.

[0262] Improvement 2 of Example 6 Improvement 2 of Example 6 is achieved by using an air spring instead of the metal spring in Figure 6.1, with the rest remaining the same. A normal air spring has a small displacement. To obtain a large displacement, a transmission device is used to increase the output displacement of the air spring. Air springs have the great advantage of being applicable to large loads. Air springs have a small structure and the air spring force can be adjusted. The spring force changes by adjusting the air pressure. High applicability. In this configuration, permanent magnet springs and electric springs can also be used, but both require a large original displacement.

[0263] Improvement 3 of Example 6 Two rows of tension springs are installed, one above the other. There are two pulleys. Suitable for large loads. In Figure 6.1, a gasket is used between the cable spring holder and the mounting base to change the length of the force application device, preload the force application device, or change the magnitude of the initial force. The gasket corresponds to the adjustment device.

[0264] In Examples 4 to 6, the spring does not swing along with the actuating cylinder, which reduces the inertia of the system. Also, since the force applying device is located outside the working space of the actuating cylinder, there is no interference with the actuating cylinder. The structure is simple.

[0265] Example 7 As shown in Figure 7, a closed loop configuration is shown in which the tension force is generated by a gravity pendulum, there is an indirect counterweight, there is no support disk, and the cable direction is changed twice.

[0266] Except for the force generating device of the force applying device, the overall structure is almost the same as that of Example 6. The difference is that in the force generating device of the force applying device, the pulling force is provided by a gravity pendulum.

[0267] The gravity pendulum includes a gravity pendulum swivel 2.2g, a swing rod 2.2d, and a counterweight 2.2e. The swing rod 2.2d is connected to the gravity pendulum swivel 2.2g. The swivel is attached above the frame body. A cable is connected to one end of the mass counterweight. The counterweight provides tension when the gravity rod swings. The cable is connected to the actuating cylinder via a fixed pulley and a water wheel of the direction adaptor.

[0268] This gravity pendulum swings within a specific range of a to 90 degrees (a is the angle between the swing rod and the horizontal plane, and is usually 20 degrees; the larger a, the closer to linearity). The length R3 of the gravity pendulum's movable rod is greater than R1, and the swing angle of the gravity pendulum's movable rod is smaller than the pitch operating space of the working cylinder. The swing rod's swing space is a continuous space close to the vertical axis, and is usually 60 degrees or less. This section is close to linear characteristics and meets engineering requirements.

[0269] In this embodiment, the pitch operating space of the actuating cylinder is 15 to 85 degrees. The operating space of the swing rod is 50 degrees (40 to 90). The length of the swing rod is approximately 1.5R1. The distance between the initial position of the cable connection point on the swing rod and the end position of the connection point is equal to the distance between the initial position of the cable connection point on the actuating cylinder and the end position of the connection point on the actuating cylinder. The gravity pendulum provides approximately linear tension force characteristics. The fixed pulley that fixes the direction of the second stage of the cable is attached close to the direction adaptation device and has a small overall height. For other parameters, see Example 6.

[0270] The initial position of the counterweight corresponds to the position of the counterweight at the minimum pitch angle of the actuating cylinder. The initial position of the counterweight is directly below the fixed pulley. In the initial position of the cable, the axes of the second and third sections of the cable overlap, or the angles between them are extremely small. The smaller the angle, the smaller the weight of the counterweight required. Due to space limitations, in Figure 15, the first and second sections of the cable form a small angle, and in this case, the weight of the counterweight is large. In the initial position, the angle between the movable rod of the gravity pendulum and the horizontal plane is about 40 degrees, and when the counterweight swings to the bottom, the travel space is about 50 degrees. This travel space of 50 degrees corresponds to the entire pitch working space of the actuating cylinder.

[0271] Note: The freely swinging connecting bar device is omitted in Figure 7. Figure 7 is an open loop structure diagram.

[0272] Example 8 As shown in Figure 8, Example 8 has a semi-closed loop structure. That is, the same slewing bearing is shared. Its same feature is that a slewing bearing is used instead of one slewing pair of the direction adapting device 3 and one slewing pair of the universal joint of the universal swing rod device 4, the axis of the slewing bearing is perpendicular to the horizontal plane, and the slewing bearing forms part of the base frame. The base frame has one degree of rotational freedom. A support disk is fixedly connected to the rotating disk of the slewing bearing, and other components, such as a U-shaped seat, a force generating device, or a branch mount, are attached to the support disk.

[0273] 1. Base frame The base frame 1 is composed of a slewing bearing 4.2a and a submount 1.2b. The slewing bearing 3.2a (4.2a) mainly includes a rotating disk and a fixed disk. The fixed disk device is fixedly connected to the ground and becomes the connection device 1.1. The supporting disk 3.2b is fixedly connected to the rotating disk, and the submount 1.2b (one or more) is fixedly connected to the supporting disk, and the rotating disk, supporting disk and submount form a rigid frame body 1.2. The axis of the slewing bearing is perpendicular to the ground (an error of approximately ±10 degrees is possible). The slewing bearing 4.2a, supporting disk 3.2b and submount 1.2b form the base frame 1. The support disk and the rotating disk are integral, and the support disk extends from the slew bearing. Slewing bearing: Not limited to engineering slewing bearings. In this specification, any bearing that is subjected to axial and radial forces as well as a large overturning moment is called a slewing bearing.

[0274] 2.Force adding device The force application device is similar to that in Example 6 and includes a force generation device 2.2a and a force transmission device 2.3a. The force generation device is similar to a tension spring 2.2a, and the force transmission device is a cable 2.3a. The force applying device and the actuating cylinder connecting rod are connected by a hollow revolving pair or hollow universal joint. As in Example 6, the cable 2.3a undergoes a second change of direction by a fixed pulley 2.3b. In this embodiment, the axis of the second cable section does not need to be perpendicular to the ground. The tension spring can be a combination spring or a series of parallel springs, or a series of parallel springs. The third cable section runs from one side of the support disk 3.2b to the other, making use of the length of the support disk and providing more space for the spring. For the magnitudes of R1 and R2 and the spring stiffness, refer to Example 1. There are various points of application that can be selected: the axis of the force applying device may lie in a vertical plane passing through the connection point of the universal joint receiving point and the actuating cylinder, or in a plane parallel to said vertical plane.

[0275] 3. Directional Adaptation Device The slewing bearing 3.2a is the vertical axis rotation pair A3.2 of the direction adaptation device 3, and the horizontal axis rotation pair B3.3 of the direction adaptation device 3 is attached to the tip of the submount 1.2b of the base frame 1. This rotation pair has one pulley connected to the force application device. The axis of the horizontal axis rotation pair B3.3 is perpendicular to the axis of the vertical shaft, either coplanar or non-coplanar (it does not have to be parallel, but perpendicular is the preferred form).

[0276] 4. Universal joint support swing rod device The universal joint receiving swing rod device includes a universal joint and an actuation cylinder connecting rod. The slewing bearing 4.2a serves as the first slewing pair of the universal joint 4.2 and is the vertical axis of the universal joint. The rotating disc of the slewing bearing is fitted with a horizontal slewing pair 4.2b (in this example, the horizontal slewing pair is mounted on a submount) which serves as the second slewing pair of the direction adapting device. The axes of the horizontal and vertical axes are perpendicular, either coplanar or non-coplanar. The horizontal slewing pair is what mounts the swing connecting rod 4.3a (or actuating cylinder). It is an assembly form in which two swivel pairs are integrated: the first swivel pair of the universal joint, the first swivel pair of the direction adapting device 3, and the lower part of the base frame 1 are integrated. The two rotational pairs of the universal joint 4.2 are perpendicular to each other and may be coplanar or non-coplanar. The spring is located below the actuating cylinder and occupies the space below the actuating cylinder. This is consistent with the perturbation spaces of the other components.

[0277] 5. The integrated external connection devices 5A5.1 and 5B5.2 include the connection between the fixed disk of the slewing bearing (which is also the connection part of the base frame) and the ground, and the connection between the universal joint and the working cylinder or the connection between the working cylinder and the platform. This embodiment differs from embodiment 6 in the following respects: 1. The force generating device is attached to the support disk (rather than to the bottom of the foundation or base frame). 2. The direction of the second section of the cable does not have to be perpendicular to the ground. 3. The two swivel joints of the direction adapting device are widely spaced and connected together by a submount, i.e., the base frame and the direction leveling device share some components.

[0278] Improved version of Example 8 The force application device is changed to a double spring device or a double double combined spring. Two sets of springs, two cables, and two sets of pulleys are located on both sides of the working cylinder (top view). In this way, the springs are not located directly below the working cylinder, reducing the height and the size of the structure. The tension force of the anti-gravity moment is limited only within a plane passing through the axis of the actuating cylinder and perpendicular to the ground. This simplifies the load bearing. Improved examples 8, 9 and 10: the slewing bearing is hollow, the support disk is also hollow, and the first slewing pair of the freely swinging connecting rod and the slewing pair of the direction adapting device are separate, that is, the freely swinging connecting rod is independent, that is, the same slewing bearing is not shared, and a large closed loop structural form is obtained. In this form, the slewing bearing is part of the base frame, that is, the base frame has one rotational degree of freedom.

[0279] Example 9 This embodiment is a large closed loop configuration with a slewing bearing, two sets of springs on each side, and one change of cable direction.

[0280] It is an improved version based on Example 8. There are three main changes:

[0281] The first change is the change in the connection method and location between the force application device 2 and the connecting rod. The connecting rod 4.3b is perpendicular to the axis of the actuating cylinder. The axis of the connecting rod changes from parallel to the actuating cylinder to perpendicular to the actuating cylinder, and the positions of R1 and R2 also change (see Figure 9). The connecting rod 4.3b is connected to the cable 2.3a by a universal joint (or swivel or spherical hinge).

[0282] The second change is that the horizontal axis 3.3 of the direction adaptation device 3 is mounted on one side, not above. The horizontal axis 3.3 of the direction adaptation device 3 is on a plane that passes through the axis of the actuating cylinder and is perpendicular to the horizontal. The mounting position is such that R2 = R1, where R2 is the distance between the contact point A2a of the cable with the pulley and the center of the universal joint. As shown in Figure 9.1, A2a is usually on a horizontal plane that passes through the center of the universal joint. A1a is not located near the axis of the actuating cylinder. A1a is on the connecting rod.

[0283] The third modification is to use two sets of springs, two cables, and two sets of pulleys, each located on either side of the actuating cylinder (top view). In this way, the springs are not directly below the cylinder, so the height is reduced. The geometric size is reduced. Also, the upper pulley is away from the range of the pitch working space of the actuating cylinder, so interference is avoided.

[0284] Other than the mentioned symbols, the remaining symbols are the same as in Example 8.

[0285] In Examples 8 and 9 (see Figures 8 and 9), a force adjusting device is connected in series between the force generating device of the force applying device and the base frame. This force adjusting device can be a regular bolt (2.5) or a basket bolt, and tensions the force applying device. In this example, a 2.5 bolt is used. Once the adjustment meets the requirements, locking, e.g., self-locking, occurs.

[0286] This adjustment device may be achieved by adding a gasket to change the cable length, etc., and in other words, there are various ways to achieve it. Changing the length of the cable is also conceivable. For example, in Example 14, if the center of gravity of the actuating cylinder is not on the axis of the actuating cylinder (is slightly off), the initial force changes slightly, but the change is small. The initial force adjustment device can meet such requirements. Of course, this adjustment device does not have to be provided, and the required value can be met during design or assembly.

[0287] Improvement 1 of Example 9 As shown in Figure 9.2, the slewing bearing is hollow, the support disc is hollow, and the universal joint of the swivel connecting rod is changed to a separately mounted large closed loop. The universal joint and the direction adapting device do not share a swivel pair. In Figure 9.2, the universal joint receiving connecting rod is removed.

[0288] Improvement 2 of Example 9 A single-sided spring is used, which reduces the perturbation space of the force application device, making it easier to install two adjacent UPS branches and reducing interference. In this example, the length of the connecting rod can also be adjusted.

[0289] Example 10 As shown in FIG. 10, this embodiment has a slewing bearing and generates torque by a torsion spring in a semi-closed loop.

[0290] Example 10 differs from Examples 8 and 9 in that the force application device provides torque using a torsion spring. In this example, the force generation device is a torsion spring, and the force transmission device is a rigid load-bearing rod. The rigid load-bearing rod may be a straight rod or a bent rod. If a bent rod is partially present, interference is avoided.

[0291] For the base frame 1, referring to Examples 8 and 9, two types of swivel pairs are attached to the support disk 3.2b. One is the horizontal axis swivel pair 4.2b of the universal joint (the axis of the actuating cylinder is vertical), and the other is the horizontal axis swivel pair 3.3 of the direction adaptation device 3, whose horizontal axis is a flexible motion pair. The axes of these two swivel pairs are parallel (or may overlap). The axis of the slewing bearing 3.2a is either coplanar and perpendicular to one of the two swivel pair axes, non-coplanar and perpendicular to the other, or non-coplanar and perpendicular to both. The horizontal axis is attached to the support disk by a mounting base, and one end of the torsion spring 2.2b is fixed to one end of the horizontal shaft 2.2j, and the adjustment device 2.5 is positioned thereon. The adjustment device can change the initial moment of the torsion spring. The axis of the torsion spring and the axis of the horizontal shaft of the direction adapting device overlap, and the torsion spring can twist around the axis of the horizontal shaft, forming a flexible turning pair.

[0292] The other end of the torsion spring is connected to a part of the connecting rod. The connecting rod 2.3f of the torsion spring and the working cylinder are movably connected to form a leading pair. The force is transmitted to the working cylinder.

[0293] There are various types of movable connections. These include sliding connections, rolling connections (linear bearings), and swivel connections, which result in leading connections. For example, as shown in Figure 10, in the first type, the radius of the moment arm of the working cylinder is constant, but the connection point of the torsion spring varies, meaning the radius of the moment arm of the torsion spring changes. In the second type, the radius of the moment arm of the torsion spring is constant, but the connection point of the working cylinder varies, meaning the length of the moment arm of the working cylinder changes. In both of these cases, the torsion spring is attached at approximately the same position, both in the second quadrant. The moment characteristics provided are similar, both provide convex curves, with small deviations from a sine curve, resulting in high accuracy of less than 5%.

[0294] The second type is the reverse of the first type, with the pulley fixed to the torsion spring rod and the sliding rod attached to either side or directly above the actuating cylinder. The slide rail in the second type is located above the actuating cylinder, and a pulley is attached to the moment arm of the torsion spring. The pulley cooperates with the rod of the actuating cylinder and rolls on the rod. As the pulley rolls, the connection point between the torsion spring and the actuating cylinder changes, and the length of the moment arm on the actuating cylinder changes. In Figure 10, the connecting rod 2.3f is connected to the actuating cylinder by a slotted wheel (which may be a sliding connection) and applies an anti-gravity moment to the actuating cylinder. When the actuating cylinder performs pitch oscillation, the connecting rod moves relative to the slotted wheel. Changing the length of the moment arm due to the straight rod changes the torque characteristics of the torsion spring with respect to the horizontal axis of the universal joint. The axis of the connecting rod that contacts the largest slotted wheel is parallel or nearly parallel to the axis of the actuating cylinder. In this embodiment, the moment arm length of the actuating cylinder is maintained.

[0295] The third type of structure is one in which a linear bearing is fitted to the connecting rod to transmit torque and allow relative movement between the actuating cylinder and the connecting rod.

[0296] The axis of the torsion spring is attached at this position. Coordinate system in Figure 10.2: Create a plane coordinate system in a vertical plane passing through the axis of the working cylinder, with the origin at the center of the universal joint, the X-axis horizontal, and the Z-axis perpendicular to the horizontal plane.

[0297] By properly designing the coordinate position of the torsion spring axis, the torsion spring stiffness, and the initial torque (torque when the angle is 0), the requirement for high precision can be met.

[0298] Specific calculation process (see Figures 10.2 and 10.3) The torsion spring stiffness is taken as a constant. Create a curve of the gravity moment of the working cylinder (a sine curve is shown in Figure 10.3). The line connecting the start point (the point corresponding to the minimum pitch angle or the origin, M3 in the figure) and the end point (the point at the maximum pitch angle or 90 degrees, Ma in the figure) is taken as the minimum stiffness line La of the torsion spring. A straight line obtained by drawing a tangent to the gravity moment curve through the starting point is defined as the torsion spring maximum stiffness line.

[0299] Usually, one stiffness line is selected from the maximum stiffness line and the minimum stiffness line to be used as the torsion spring stiffness characteristic. For example, Lb in Figure 10.2 (connecting M1 and M2) or Lc in Figure 10.2 (connecting the origin and M3) can be used.

[0300] In certain cases, a straight line may be selected that is greater than the maximum stiffness (for example, if the requirement for gravity compensation is high) or less than the minimum stiffness (for example, if the requirement for accuracy is low). A stiffness value is selected from within this interval or near the outside of this interval. After optimizing the stiffness value, the stiffness value, starting torque and mounting position of the torsion spring are obtained.

[0301] The mounting position of the torsion spring may be selected from a rectangular section whose coordinates on the X-axis are within the interval (0.05R0~-0.28R0) and whose coordinates on the Y-axis are within the interval (-0.05R0~0.28R0). For mounting points within this region, the torque characteristics of the horizontal axis of the universal joint change from the conventional linear characteristics to convex curve characteristics (or, in most cases, a convex curve or a concave-convex curve, and in certain cases, a linear characteristic, but both are close to a sinusoidal curve). The specific position is optimized and designed according to the actual situation.

[0302] The optimal mounting position for the torsion spring is in a small rectangular area where the coordinates on the X axis are in the range (-0.18R0 to -0.22R0) and the coordinates on the Y axis are in the range (0.18R0 to 0.22R0). Different stiffness values ​​result in different initial forces, which can lead to discrepancies.

[0303] In this example, the coordinates of the axis of the torsion spring are (-0.2R0, 0.2R0) (the radius of the center of gravity of the design point of the working cylinder is R0). The torsion spring stiffness curve is Lb (Figure 10.3). The design point is the gravity moment when the piston is in neutral position.

[0304] Method: For a given object, the antigravity moment and key parameters are determined. First, determine the stiffness value for the torsion spring, then select the zero torque position (initial force), select the mounting position, calculate the torque in the working space, and compare the results with the error (the difference between the actual torque curve and the sine curve).

[0305] In all operating spaces (mainly the pitch operating space), if the difference between the gravity moment and the anti-gravity moment meets the tolerance requirement, then it can be stopped. Usually, the optimum result is that the upper and lower deviations are nearly equal.

[0306] If not, try varying the initial force, mounting location, and stiffness, and repeat the process until you achieve a satisfactory result. Results are usually not unique. Typically, the positive and negative deviations of the anti-gravity and gravity moments are roughly equal across the pitch operating space. The smaller the deviations, the better.

[0307] There is no order in which the initial force, attachment position, and stiffness are selected. For example, the attachment position may be determined before the other variables are determined, or the initial force may be determined before the other variables are determined.

[0308] In Example 10, a torsion spring initial torque adjustment device is provided. In FIG. 10, the adjustment device is a bolt. By turning the bolt, the initial torsion force of the torsion spring can be adjusted, and after adjustment, the torsion spring locks, e.g., self-locks. In this way, the initial torsion force of the torsion spring changes. Theoretically, when the axis of the actuating cylinder is perpendicular to the ground, the corresponding torsion spring torque is usually 0. In many cases, the maximum pitch angle is 90 degrees or less. For example, an error of 5% or less is allowed. In this example, the torsion spring may be adjusted and locked with an initial force by means of an adjustment device 2.5.

[0309] Improvement 1 of Example 10 The slewing bearing is hollow, the support disc is hollow, and the UPS branches are changed to an independent large closed loop.

[0310] Based on Example 10, the (RPS) part of the universal joint branch is removed, the support disk is made hollow, and the slewing bearing is kept hollow. The UPS branch is attached to the hollow part, and a force applying device is connected to the UPS branch, and an anti-gravity moment is applied to the branch. This results in the form of Improvement 1 of Example 10 (Fig. 10.4).

[0311] The rest is almost the same as in Example 10. The reference numerals refer to Example 9. Torsion spring improvement Combination springs (two springs, one large and one small, nested together) or single-sided springs are used.

[0312] A common feature of Examples 8, 9, and 10 is their semi-closed loop structure. That is, they share the same slewing bearing. A common feature of these examples is that one slewing bearing is used instead of one slewing pair of the direction adapting device 3 and one slewing pair of the universal joint of the universal swing rod device 4, the axis of the slewing bearing is perpendicular to the horizontal plane, and the slewing bearing is also part of the base frame. The base frame has one degree of rotational freedom. A support disk is fixedly connected to the rotating disk of the slewing bearing, and other components, such as a U-shaped seat, a force generating device, a branch mount, etc., are attached to the support disk.

[0313] Example 11 As shown in Figure 11, Figure 11.1 shows a configuration in which a counterweight is used as a force-adding device.

[0314] Based on Example 10, the force application device is removed and the horizontal axis U-shaped seat of the universal joint is raised. The connecting rod is connected to the cylinder barrel. The connecting rod extends in the opposite direction to the axis of the actuating cylinder, and a counterweight is provided on the connecting rod, which applies an anti-gravity moment to the actuating cylinder (in the figure, the counterweight is connected to the connecting rod on the left side of the horizontal axis). The counterweight is fixedly attached in a position opposite to the axis of the actuator. Its weight cancels or partially cancels the gravitational moment. Two sets of counterweights are located on either side of the axis of the actuating cylinder (viewed from the top view, Figure 11.1). The counterweights do not interfere with the universal joint.

[0315] In this example, the connection between the counterweight and the actuating cylinder is a fixed connection, which is also one of the transmission devices.

[0316] The force applying device 2 is a counterweight 2.2e. The base frame 1, the direction adapting device 3, and the universal joint 4.2 share the same horizontal swivel pair, and the swivel bearing and the horizontal swivel pair also constitute the base frame. It is an assembly form in which the three are integrated. The structure is simple. In this form, the U-shaped fork is high, so the total height is large.

[0317] Example 12 Another counterweight configuration is shown in Figure 12 and Figure 12.1, which is a counterweight configuration with a symmetrical transmission system, where the counterweights are located on the same side of the working cylinder as shown in Figure 12 and Figure 12.1.

[0318] The transmission mechanism places the counterweight on the same side of the actuating cylinder, allowing the axis of the actuating cylinder and the counterweight to move symmetrically in the horizontal plane (side view). The actuating cylinder is the driving side, and the counterweight is the passive side. The counterweight provides an anti-gravity moment. Such symmetrical transmission can be achieved in various ways, such as by using a pair of gears (or small-tooth gears) with the same number of teeth and the same radius, or by using a pair of wheels connected by a steel cable to rotate synchronously in opposite directions.

[0319] In the following, gear transmission will be taken as an example.

[0320] The structures of the base frame 1, the direction adaptor 3, and the universal joint are the same as those of the tenth embodiment. Only the mounting method of the counterweights differs from that of the tenth embodiment. The counterweights are meshed with each other by gears 2.3c with the same number of teeth. One gear is connected to the axis of the working cylinder (the horizontal axis of the universal joint) for synchronous transmission and is the driving gear, while the other gear is connected to the counterweight and is the passive gear. The counterweight, attached to the passive gear by a connecting rod, is located inside the platform. In this embodiment, the passive gear is mounted on top of the driving gear, thus minimizing the increase in overall height. The driving gear and passive gear are both located on both sides of the working cylinder. One counterweight is located on each side of the working cylinder.

[0321] The two gears move symmetrically on the horizontal plane, balancing the antigravity moment and gravity moment. This configuration reduces the overall height but increases the inertia significantly. The working spaces of the two counterweights are located on both sides of the working cylinder and do not interfere with each other. Moreover, the overall height is significantly reduced. Also, external space is saved.

[0322] Improvement 1 of Example 12 is a large closed loop with a counterweight on one side, a gear on one side, no perturbation space on one side of the working cylinder, and a small installation distance between two adjacent UPS branches.

[0323] Example 13 A closed-loop configuration with a slewing bearing that changes the cable direction three times is shown in Figure 13. Figure 13.1 shows a partial view of the pulleys responsible for the second and third direction changes (section C2-C2 in Figure 13).

[0324] In this embodiment, based on the eighth embodiment, one pulley 2.3i is added to the support disk (one on each side, or a pair of pulleys is also possible), and the axis of the added pulley 2.3i is perpendicular to the horizontal plane. The axis of the pulley 2.3e, which changes the direction of the horizontal axis, and the axis of the pulley 2.3i, which changes the direction of the vertical axis, are perpendicular to each other. The rest is the same as in the eighth embodiment.

[0325] The cable passing through the second pulley 2.3e may be further redirected by the third pulley 2.3i. The cable 2.3a is wound around the fan-shaped surface of this pulley, and the point C where the cable first contacts this pulley 2.3i (see Figure 13.1) is on the axis of the slewing bearing. When the rotating disk 3.2b rotates, the second pulley rotates, and this initial contact point C remains unchanged. The third pulley rotates around the slewing bearing, causing a slight oscillation in the fourth section of the cable, but this does not affect its operation. The connected force generator 2.2a may be mounted on the ground. However, as the rotating disk rotates, the angle at which the cable is wound around the fan-shaped surface perpendicular to the pulley also changes, resulting in a slight change in the length of the cable. This results in a slight error, but due to the small diameter of the pulley and the small rotation angle, the error is extremely small and within engineering limits.

[0326] In this example, the tension spring is provided with an organ-like protective cover.

[0327] Example 14 As shown in Figure 14, Example 14 is a hybrid force application configuration with one support disk, closed loop, and a combination of gravity and cable springs, and Figure 14.1 is a top view of it.

[0328] It is a combination of Example 11 and Example 8. Based on Example 11, since the motor counterweight is insufficient to offset the gravity moment, a spring is used to offset part of the gravity moment so that the inertia does not increase excessively. Two sets of tension springs are arranged on both sides (or one set is arranged on only one side). A cable is connected to one end opposite to the axis of the actuating cylinder (below the motor in the figure), and the axis of the spring is perpendicular to the plane of the base platform.

[0329] The second turning pair of the direction adaptor is located below the universal joint. Position changes also occur for R1 and R2 (see Figure 14). For the relevant symbols, see Figures 8 and 10.

[0330] Example 15 FIG. 15 shows an open loop configuration in which a tension spring and a cable are combined and the direction of the cable is changed twice.

[0331] Example 15 is an improvement of Example 6. In Figure 6, the universal joint connecting rod 4 (working cylinder), i.e., the part indicated by the dashed line in Figure 15, is removed. An open loop configuration is obtained.

[0332] In Example 15, the direction adaptor 3 has a vertical axis located below the horizontal axis, and the revolving pair with a vertical axis is a hollow shaft. The eccentricity e1 is equal to the radius of the pulley. The cable passes through the hollow shaft. The radius of the pulley is the minimum radius of the pulley plus the radius of the cable. When the pulley swings, the axis of the second stage of the cable does not change and is always at the center of the hollow shaft.

[0333] For ease of transportation, in Example 15, the base frame is foldable. At the center of the frame body of the base frame, the frame body is divided into two parts, upper and lower, and a swivel joint 1.5 and a locking device are provided at the center of the main mount. When unfolded and locked with a fixing bolt, a rigid frame is obtained. When folded, a base frame is obtained, which is thus advantageous for transportation. For details such as symbols, please refer to Example 6 and Figure 6.

[0334] Example 16 FIG. 16 shows a semi-open loop configuration with a disk and tension generated by a torsion spring.

[0335] Based on Example 8, the force application device is removed, and the freely swinging connecting rod is attached to the support disk. The force application device is changed to the force application device of Example 3. Thus, Example 16 is obtained.

[0336] In Example 16, the torsion spring is mounted above the base frame, with point A2a located above the universal joint, allowing for a given eccentricity.

[0337] Modification 1 of Example 16 (see Figure 16.1) Based on Example 16, the support disk is hollowed, a slewing bearing is placed in the hollow, and the universal joint of the swivel connecting rod is attached to the hollow portion. A U-shaped fork 6 is added to the support disk directly below the actuating cylinder, and the actuating cylinder is located within the U-shaped fork 6 (the part that cooperates with the U-shaped fork 6, and the cross section of the actuating cylinder or connecting rod is circular) and has a loose fit with the U-shaped fork. This is a coupling in a broad sense. The actuating cylinder drives the U-shaped fork to rotate around the horizontal axis, which rotates the support disk, thus achieving synchronous rotation. When the actuating cylinder performs pitch rotation, the U-shaped fork does not move.

[0338] Example 17 FIG. 17 shows a semi-open loop configuration in which torque is generated by a torsion spring.

[0339] Example 17 is a modification of Example 10. The actuating cylinder (i.e., the swing connecting rod), the horizontal axis of the universal joint, and the mounting base are removed. The rest are the same as Example 10. Thus, Example 17 is obtained. Example 17 is a semi-open loop type, and one slewing bearing is shared (the universal joint and the direction adapting device share the same slewing pair, and this slewing pair becomes part of the base frame, simplifying the structure, and the force applying device does not generate a component force that passes through the axis of the actuating cylinder and is perpendicular to the horizontal plane).

[0340] Improvement of Example 17 (Reference Figure 17.1) Based on Example 18, the actuating cylinder, the horizontal axis of the universal joint and the mounting base are removed, and the support disk is made into a hollow support disk, and the center of the slewing bearing is kept hollow. The hollow part is used to mount the universal joint of the free-swinging connecting rod. Example 17 is a large open loop type. In the open loop configuration, Figures 16, 16.1 and 17, the freely swinging connecting rod arrangement should be removed.

[0341] Example 18 18 is a top view of Example 18. Example 18 is an open loop configuration with a gravity counterweight.

[0342] The front view is shown in Figure 12, and Figure 18 is a top view of Figure 12. In Example 12, the actuating cylinder drives the counterweight via the horizontal shaft of the universal joint. As shown in Figure 12.1, the shaft is a long shaft. In Example 18, the shaft is divided into two (or three) shafts with the same axis, and their intermediate sections are connected by a coupling 5.2b, which replaces the conventional long shaft, resulting in Figure 18. Two U-shaped seats are attached to the outer periphery of the slewing bearing (support disk). The U-shaped seats have a horizontal rotating shaft, which overlaps with the horizontal shaft of the universal joint and is connected to the universal joint by a coupling. The counterweight is attached to the shaft of the U-shaped seat of the slewing bearing (support disk). In Figure 18, the counterweight is connected by a gear. When the actuating cylinder performs pitch oscillation, it rotates the coupling, and when the shaft of the U-shaped seat rotates, it oscillates the counterweight. The connecting rod of the actuating cylinder and the counterweight moves symmetrically in the horizontal plane, and the counterweight provides the appropriate anti-gravity moment.

[0343] The slewing bearing is hollow, and the center of the support disk is also hollow. The hollow area is the mounting space for the U-joint of the UPS branch. Figure 18 shows the freely swinging connecting rod device. However, in the large open loop configuration, this freely swinging connecting rod device does not exist.

[0344] In use, a universal joint is attached to the center of the slewing bearing and connected to the actuating cylinder, thus the universal joint and the actuating cylinder become UPS branches, which may be independent. In this way, a large force closed loop structure is obtained.

[0345] Below, we will cite an example of a six-degree-of-freedom parallel mechanism using a side force reduction device as a representative example, and refer to this parallel mechanism as a slight positive pressure parallel mechanism. The invention can also be applied to other parallel mechanisms with fewer degrees of freedom.

[0346] Example 19 The minute positive pressure parallel mechanism is a combination of a 6-UPS (or 6-UCS, 6-UCU) parallel mechanism and an open-loop side force reduction device (Example 6). The minute positive pressure parallel mechanism has three axes of symmetry (only one-third of the parallel mechanism system is shown in Figure 19, and the same is true for Figures 20 and 21). A direct-coupled electric cylinder is used for the P joint. This configuration can be used to modify conventional parallel mechanisms and to design new minute side force parallel mechanism systems.

[0347] Regarding the installation location of the side force reduction device, the leading joint has a conical working space. The projection of the boundary of this conical working space onto a horizontal plane forms an angle, and an axis of symmetry (called a bisector) can be determined for this angle. Generally, the installation location is related to this axis of symmetry (called a bisector). It is preferable to install the device on this axis of symmetry, for example, directly above the joint support point. Alternatively, the joint support point is on the axis, or directly above this axis outside the joint support point. This installation location is preferable because the forces applied to both left and right deflections are approximately the same. In other words, if there is eccentricity, the force application state with the eccentricity is good. If the force application is not on this axis, the force application state with such eccentricity may be larger on one side. However, this does not affect normal operation, and in this case, this force should be taken into account in dynamic analysis. The base is attached to the outside of the universal joint, and the connection point between the force application device and the frame is located above the universal joint.

[0348] Example 20 The slight positive pressure parallel mechanism is a combination of a 6-UPS (or 6-UCS, 6-UCU) parallel mechanism and a closed-loop side force reduction device (Example 10). A single-sided or double-sided torsion spring is used as the force application device. A hydraulic cylinder is selected as the P pair.

[0349] Example 21 The slight positive pressure parallel mechanism is exemplified by a 6-UPS 6-DOF parallel mechanism, and the side force reduction device is the three-in-one configuration in the tenth embodiment.

[0350] This configuration is primarily used when designing new, minute side-force parallel mechanism systems (it can also be used to modify conventional hydraulic parallel mechanisms). It can be applied to parallel mechanisms with few degrees of freedom, such as 3-UPU, 4-UPU, and other parallel mechanisms that include UPS-type branches. It can be used to modify conventional parallel mechanisms and design new parallel mechanisms.

[0351] Examples 19, 20, and 21 are essentially identical micro-side force parallel mechanism systems. In these three examples, the above-mentioned reduced side force device (open loop type) is applied to a parallel mechanism. Specifically, the open loop reduced side force device further includes a parallel mechanism having at least one UPS-type branch, and the cylinder of the leading joint of the UPS branch is connected to one end of a force application device to apply an appropriate anti-gravity moment to the actuating cylinder, thereby achieving a micro-side force (very small friction force and a certain weight compensation ability) parallel mechanism system. Typically, a parallel mechanism has the same number of open loop reduced side force devices as the number of UPS-type branches, and the reduced side force devices are located below or outside the parallel mechanism, eliminating interference between moving members.

[0352] Examples 19, 20, and 21 may be considered as a parallel mechanism consisting of multiple (1 to 6, normal branches) closed-loop side force reduction devices (with complete UPS branches). For example, in the six devices shown in FIG. 1, when the six UPS branches are equipped with movable and fixed platforms according to the configuration of the parallel mechanism, the six UPS branches become a six-degree-of-freedom parallel mechanism, i.e., a micro-positive pressure parallel mechanism system. This parallel mechanism system has extremely small friction and a certain weight compensation capability. In terms of assembly, the side force reduction devices are usually located below or outside the parallel mechanism, so that the moving members do not interfere with each other.

[0353] Similarly, all closed-loop side force devices can form a corresponding parallel mechanical system.

[0354] Examples 1 to 14 are mainly closed-loop configurations. Examples 15 to 21 are open-loop configurations, including large open-loop configurations and semi-open-loop configurations. For Examples 1 to 6, the universal swing rod device is removed to obtain a large open-loop configuration. For Examples 8, 9, and 10, the horizontal shaft and actuation cylinder of the universal joint are removed, the center of the support disk is kept hollow, the center of the slewing bearing is kept hollow, and the connection device of the force-applying device is changed to an external connection device, thereby also obtaining a large open-loop configuration. For Examples 8, 9, and 10, when the horizontal shaft and actuation cylinder of the universal joint are removed, a semi-open-loop configuration is obtained (the direction adapting device and the universal joint share the same slewing pair, i.e., the same slewing bearing).

[0355] An example will be described below.

[0356] Regarding the essence of the method, all the embodiments describe the following comprehensive method. That is, the side force reduction method essentially involves providing a reduction device and applying a force between the actuating cylinder and the foundation, one component of which cancels the antigravity moment and which also has an upward component that allows for weight compensation. This antigravity moment and gravity compensation provide appropriate antigravity moment and gravity compensation when the pitch angle changes, and when the yaw angle changes, the antigravity moment and gravity compensation do not change, or only change within the limits of engineering tolerance. Therefore, this method provides appropriate antigravity moment and gravity compensation. The so-called appropriate antigravity moment refers to the antigravity moment generated by the force application device meeting the design requirements regardless of the pitch angle.

[0357] Regarding the iteration of the method, the iteration process is performed by making a comparison according to specific requirements in a specific embodiment. For example, for a specific design proposal, specific anti-gravity moment and specific weight compensation requirements are given, and then it is confirmed whether the design objectives have been achieved. In this case, iteration can be performed. The examples are simply the results of the iteration.

[0358] Regarding the order of A and B in the first step of the method, when there is a specific application, that is, when a client provides a specific flight simulator motion system (for pilot training) with clear structural parameters, clear requirements for gravitational moment and weight compensation, and specific design requirements, the structure to which this 6-DOF motion system is applied is determined. That is, first the main parameters are determined, and then the structure is determined. In other words, the order is A and B. Such a method is used in Example 6.

[0359] After selecting the structure of one embodiment, when applying this embodiment to a specific multi-degree-of-freedom parallel mechanism, the force application method and structure are determined first, and then the parameters are determined. This includes requirements for anti-gravity moment and gravity compensation. For example, in the first embodiment, this method is used when applying it to a car driving simulator. In other words, the order is B and A.

[0360] Therefore, in the embodiment, the order of A and B is arbitrary, and they may be performed simultaneously.

[0361] Force application device pulleys and cables In several embodiments, the force transmission device of the force application device uses a pulley or cable, and the direction of the first section of the cable is determined by the mounting position of the first pulley, and the specific form is one of the following three: a. One pulley form: The pulley is attached to the base frame and shares the same horizontal axis pair as the direction adaptation device to fix the direction of the first section of the cable, and the direction of the second section of the cable is determined by the mounting position of the force generation device of the force application device, and the direction of the second section of the cable is perpendicular to the horizontal plane (with an error of about 10 degrees allowed); b. Two pulley form: The first pulley is attached to the base frame and shares the same horizontal axis pair as the direction adaptation device to fix the direction of the first section of the cable, and the second pulley is attached to the base frame, and the two pulleys work together to determine the direction of the second section of the cable, and the direction of the third section of the cable is determined by the mounting position of the force generation device. c. Three or more pulley configuration: one pulley is attached to the base frame and shares the same horizontal axis as the direction adaptor and is used to fix the direction of the first section of the cable, another pulley is attached to the base frame, and the two pulleys work together to determine the direction of the second section of the cable, and the remaining pulleys change the direction of any section of the cable as desired.

[0362] Structure Expressions In all the embodiments, the basic structure of each member includes two parts: a functional structure and an external connection device. Such a member is composed of two parts, a functional structure and an external connection device, as a whole. Therefore, from this angle,

[0363] 1. Each component is self-similar, and the whole and each component are also self-similar.

[0364] 2. Every two connectable members are connected to each other by a respective connecting device, which is their common point. If detailed descriptions and reference symbols were provided for each of the two connecting members, the specification would become too long and the focus would become unclear. Therefore, for the sake of brevity and clarity, detailed descriptions and reference symbols for the connecting parts are omitted.

[0365] Regarding the foundation, a fixed facility or device must be attached to the foundation or the ground, which means a relatively fixed facility or device. In this proposal, the base frame is attached to the foundation, the foundation platform of the parallel mechanism is attached to the foundation, the UPS branch is attached to the foundation, and the force generating device of Example 16 is attached to the foundation. According to mechanical principles, the foundation is a large member, and the member attached to the foundation is a relatively fixed member. Alternatively, multiple relatively fixed members are essentially one large member. The document does not specifically state that the mechanism includes a foundation. Therefore, in this proposal, the basic configuration does not mention a foundation, and the examples do not always mention a foundation. This does not mean that the foundation is not included, but is merely an expression.

[0366] The present invention provides a special parallel mechanism having two or three rotational degrees of freedom, comprising a base platform, two branches, and a motion platform. The first branch comprises a base frame, a force application device, and a direction adaptation device, the second branch is a universal joint (or spherical hinge), and the motion platform is a swing rod device. Between the ends of the two branches, the first branch generates a force on the connecting rod, one component of which generates an anti-gravity moment on the connecting rod and a weight attached to the connecting rod, and also generates an upward component of force on the connecting rod to offset part of the weight of the connecting rod and the weight attached to the connecting rod. This embodiment corresponds to the closed-loop structure.

[0367] The present invention also provides a series-connected mechanism (which may include series-parallel connection components), which has two or three degrees of freedom and includes a foundation platform, a base frame, a force application device, a direction adaptation device, and a motion platform (i.e., an actuator). The base frame, the direction adaptation device, the force application device, and the actuator form one series-connected branch. When this series-connected branch is applied to a universal connecting rod and forms a parallel mechanism together with the universal connecting rod, it applies a force to the connecting rod and its attachment at the universal joint, and this force has a component, which generates an anti-gravity moment on the connecting rod and a heavy load attached to the connecting rod, thereby offsetting the gravitational moment, and also generates an upward component on the motion platform, thereby offsetting part of the weight of the connecting rod and its attachment.

[0368] In this specification, there may be more than one external connection device, in addition to two, connection device A and connection device B. A and B themselves may also have multiple connection sites. This is one expression corresponding to input and output, and in some cases there may be multiple outputs and inputs, in which case there will be multiple connection sites.

[0369] The above is merely an exemplary embodiment of the present invention, and does not limit the scope of the present invention. Those skilled in the art will recognize that any equivalent changes or modifications made without departing from the concept and principles of the present invention will fall within the patent scope of the present invention. [Explanation of symbols]

[0370] 1: Base frame (Function: Provides mounting mounts for direction adaptors and force applying devices.) 1.1: External connection device 1A, i.e., the base mounting base; 1.2: Frame body; 1.2a: One or two length-adjustable members on the entire rigid frame; 1.2b: One-rotational-degree-of-freedom base frame (submount A); 1.2c: Two-rotational-degree-of-freedom base frame (submount B); 1.2d: Frame body with adjustable length or height; 1.3: External connection device 1B; 1.3a: Directional adaptation device connection base; 1.3b: Force application device connection base 1.4: Safety cover or shell; 1.5 Foldable or extendable device (advantageous for transportation). 2: Force adding device; 2.1: External connection device 2A; 2.2: Force generating device; 2.2a: Tension spring; 2.2b: Torsion spring; 2.2c: Combination spring; 2.2d: Swing rod; 2.2e: Counterweight; 2.2f: Torsion spring support; 2.2g: Gravity pendulum rotating pair; 2.2h: Spring mounting bush; 2.2i: Support shaft; 2.2j: Motor counterweight; 2.2k: Auxiliary counterweight; 2.2l: Fixed shaft; 2.2m: Force application device mounting base; 2.2k: Connection end; 2.2i: Cable rotating barrel; 2.2: Trumpet-shaped mouth; 2.2f: Torsion spring mounting base; 2.3: Force transmission device; 2.3a: Cable transmission; 2.3b: Pulley transmission pair; 2.3c: Gear transmission structure; 2.3d: Universal joint type transmission device; 2.3e: Direction change pulley; 2.3f: Torsion spring connecting transmission rod; 2.3g: Connecting rod; 2.3h: Connecting rod (delete related connecting rod); 2.3i: Rotating ring (for torsion spring); 2.4: External connection device 2B; 2.4a: Universal joints; 2.4b: Hook-and-ring universal joints; 2.4c: Flexible universal joints; 2.4d: Connection pipe (plate); 2.4e: Hollow cross shaft; 2.4i: U-shaped fork; 2.4f: Cable; 2.5: force adjusting device; 2.5a: adjusting bolt; 2.5b: gasket; 2.8: Gearbox; 2.8a: Large sheave; 2.8b: Small sheave; 2.8c: Cable A; 2.8d: Cable B; 2.8e Gearbox case; 2.8f Cable connector A; 2.8g Cable connector B; 3: Directional adaptation device; 3.1: External connection device 3A; 3.2: Slewing pair A; 3.2a: Slewing bearings; 3.2b: Support discs; 3.2c: Ordinary slewing pairs; 3.2d: Single-pulley universal joint; 3.2e: Double-joint universal joint; 3.2f: Double-pulley universal joint; 3.3: Turning pair B; 3.3a: Flexible turning pair; 3.3b: Ring; 3.3c: Rigid turning pair; 3.4: External connection device 3B. 4: Universal swing rod device; 4.1: External connection device 4A; 4.2: Universal joint; 4.2a: Slewing bearing; 4.2b: Horizontal rotating pair; 4.2c: Swing-rotating pair; 4.2d: Rotating pair centered on the axis of the working cylinder; 4.2e: Universal joint; 4.2f: Three-axis orthogonal spherical hinge; 4.2g: Four-axis orthogonal symmetrical spherical hinge; 4.2h: U-shaped seat; 4.2i: Universal joint double pulley; 4.3: Swing connecting rod, length adjustable; 4.3d: Cylinder barrel; 4.3a: Parallel connecting rod; 4.3b: Vertical connecting rod; 4.3c: Reverse connecting rod; 4.3f: Length adjustable connecting rod; 4.4: External connection device 4B; 4.4a: Connected to force application device; 4.4b: Connected to task load; 5: Integrated external connection device; 5.1: Foundation connection base 5A; 5.2: Task load connection base F. 6:U-shaped fork; System configuration: 7: UPS-like parallel mechanism; 7.1: System external connection device 7A; 7.2: Basic platform; 7.3: UPS type branch; 7.3a: Lower platform universal joint (4.2); 7.3b: Leading pair or cylindrical pair; 7.3c: Upper platform universal joint; 7.4: Exercise platform; 7.5: System external connection device 7B; 8: Side force reduction device; 8.1: Integrated external connection device 8A; 8.2: Type without support disk; 8.3: Type with support disk; Explanation of Figures 1.2 and 1.3 L0: Position of the axis of the working cylinder when the pitch angle is α L1: Position of the axis of the working cylinder at the minimum pitch angle L3: Position of the axis of the working cylinder at the maximum pitch angle L2: OA2 knot Lm: Projection of the inner boundary of the yaw angle on the horizontal plane Ln: Projection of the outer boundary of the yaw angle on the horizontal plane Lp: symmetry axis of the boundary between the two yaw angles Description of Figure 10.2: L4: Axis of the output rod of the torsion spring corresponding to the minimum pitch angle of the working cylinder L5: The axis of the output rod of the torsion spring corresponding to the axis of the working cylinder at a certain time L6: Axis of the output rod of the torsion spring corresponding to the maximum pitch angle of the working cylinder La: The stiffness line A of the set torsion spring itself (passing through O and α1) Lc: The stiffness line C of the set torsion spring itself (passing through α0 and α3) Lb: The stiffness line B of the set torsion spring itself (passing through two points on the sine curve) α: Pitch angle of the axis of the working cylinder at any time α1: Minimum pitch angle of the axis of the working cylinder α2: Maximum pitch angle of the axis of the working cylinder α3: Angle of the output rod of the torsion spring at the minimum pitch angle of the axis of the working cylinder α4: Angle of the output rod of the torsion spring at the maximum pitch angle of the axis of the working cylinder α5: The angle of the output rod of the torsion spring when the axis of the working cylinder is at an arbitrary position. β: Maximum angle of projection of the axis of the working cylinder at the maximum yaw angle on the horizontal plane β2: Tensile force deflection angle, the angle between the axis of the working cylinder and the tensile force axis R0: Radius corresponding to the center of gravity of the working cylinder, R0=OA1 Ra: Radius at the fixed end of the force application device, or radius at the first change of direction of the tension spring cable R1: Connection point between the force applying device and the actuating cylinder, R1=OA1a R2: Connection point of the tension spring to the force application device on the base frame, R2=OA2a R3: Radius of Gravity Swing Rod R4: Radius of the connection point between the torsion spring and the actuating cylinder, constant or variable. A1: The position of the center of gravity of the actuating cylinder, which may not be on the axis. A2: Another fixing point of the tension spring on the base frame A1a: Actual connection between the force applying device and the working cylinder A2a: The actual connection point between the force application device and the base frame, which determines the direction of the force. F0: The force acting on the actuating cylinder in the vertical plane of the force-applying device, for example, in the axial direction of the cable or in the direction perpendicular to the output rod of the torsion spring. F1: Component force of F0 on the axis of the working cylinder F2: Component force of F0 in a vertical plane passing through the axis of the working cylinder, in a direction perpendicular to the axis of the working cylinder F3: Component of F0 in the direction perpendicular to F1 and F2 F4: The output force of the torsion spring, perpendicular to the axis of the output rod of the torsion spring F5: Projection of F4 onto a vertical plane passing through the axis of the working cylinder and perpendicular to the axis of the working cylinder.

Claims

1. A method for reducing positive pressure in a universal joint receiving actuation cylinder, comprising: Applicable to universal joint receiving actuation cylinders, The device used in the reduction method includes a base frame, a force applying device, a direction adapting device, a universal swing rod device, and an integrated external connection device; the orientation adaptor is mounted above a base frame; One end of the force applying device is connected to the base frame by a direction adapting device, and the other end is connected to the universal swing rod device or the cylinder barrel of the universal joint receiving actuating cylinder by a connecting device; The integrated external connection device is used to connect the actuation cylinder and mount the entire device, and is connected to the task load; The reduction method includes: a force applying device providing a force, which acts between the coupling-receiving actuation cylinder and the base frame to create an anti-gravity moment and weight compensation; A first step of determining the main design parameters and type of force application device, said first step comprising: Step A determines key design parameters, including the magnitude of the maximum positive pressure of the actuation cylinder to be reduced, the ratio of the maximum gravity moment to the gravity moment to be cancelled, the maximum anti-gravity moment, and the magnitude of weight compensation; Step B of determining the type and structural form of a force application device, wherein determining the type of force application device includes determining a force application method to be used to provide an anti-gravity moment, the force application method being a tension spring, a torsion spring, a gravity counterweight, a gravity pendulum, or an air spring, and one or a combination of two or more of these force application methods can be selected, and determining the structural form is an open loop structure, a closed loop structure, a semi-open loop structure, a semi-closed loop structure, or a hybrid structure, and one of these structural forms can be selected; The first step includes: a second step of designing a device structure, in which after determining main design parameters and the type of force application device, designing the device structure including structure design, manufacturing, assembly and debugging, the design of the device structure includes the design of a base frame, a force application device, a direction adaptation device and the integrated external connection device; a third step of calculating, testing, and evaluating the actual gravity moment or positive pressure and the effect of weight compensation to determine whether the design requirements are met; calculating, or testing, and evaluating the gravity moment and reduction rate; calculating, or testing, and evaluating the effect of weight compensation; if the design requirements are met, stopping; and using the resulting design as the design result; if the design requirements are not met, adjusting the parameters, and repeating the above steps to redesign until the design requirements are met; A method for reducing positive pressure in a universal joint receiving actuation cylinder, comprising:

2. The structural design of the universal swing rod device, including the main parameter design of the universal swing rod device, including the adjustment and iteration of the parameter structure of the universal swing rod device; 2. The method for reducing the positive pressure of a universal joint receiving actuating cylinder according to claim 1, wherein the universal swing rod device is attached to the bottom of a foundation or base frame, and the other end of the universal swing rod device or the cylinder body of the universal joint receiving actuating cylinder and the force adding device are connected via an integrated external connection device to form a closed loop.

3. The second step further includes attaching a first turning pair of the direction adapting device to a foundation so that an axis of the first turning pair is perpendicular to a horizontal plane; 2. The method for reducing the positive pressure of a universal joint receiving working cylinder according to claim 1, wherein the first turning pair is a slewing bearing, a fixed disk of the slewing bearing is fixed to a foundation, a support disk is fixed on a movable disk, the support disk is fixedly attached to the slewing bearing, and the slewing bearing is a part of the base frame.

4. 3. The method for reducing the positive pressure of a universal joint receiving working cylinder according to claim 2, wherein in the second step of the reduction method, the universal swing rod device and the direction adapting device share the same swivel pair, and the shared swivel pair is a swivel pair for connecting the universal joint in the universal swing rod to the foundation, the shared swivel pair is called a slewing bearing, the axis of the slewing bearing is perpendicular to the horizontal plane, the fixed disk of the slewing bearing is fixed to the foundation, and the support disk is fixed on the movable disk, and the slewing bearing becomes a part of the base frame.

5. 2. A device for reducing positive pressure in a universal joint receiving actuation cylinder for realizing the method for reducing positive pressure in a universal joint receiving actuation cylinder according to claim 1, comprising: a base frame, a force application device, a direction adaptation device, and an integrated external connection device; The base frame includes an external connection device 1A, a frame body, and an external connection device 1B, the force applying device includes a force generating device, a force transmitting device, an external connection device 2A, and an external connection device 2B, and the force generated by the force generating device includes gravity, metal spring force, air spring force, or electromagnetic force; The direction adapting device includes two non-coaxial and non-parallel rotating pairs, and the external connection device 3A, the external connection device 3B and the two rotating pairs are fixedly connected together to enable two-degree-of-freedom rotation; The integrated external connection device includes an external connection device 5A and an external connection device 5B, and is a device for reducing positive pressure of a universal joint receiving working cylinder.

6. Further comprising a universal swing rod device; The universal swing rod device includes a universal joint, a swing connecting rod, an external connection device 4A, and an external connection device 4B, and the universal joint is connected to the swing connecting rod; The positive pressure reduction device for a universal joint receiving actuating cylinder as described in claim 5, wherein the universal swing rod device is attached to the bottom of a foundation or base frame, and the universal swing rod device or the cylinder body of the universal joint receiving actuating cylinder and the other end of the force adding device are connected via the integrated external connection device to form a closed loop.

7. 6. The device for reducing positive pressure of a universal joint receiving actuation cylinder according to claim 5, wherein the first swivel pair of the direction adapting device is attached to the ground, the axis of the first swivel pair is perpendicular to the ground, and a swivel bearing is used as the first swivel pair.

8. The device for reducing the positive pressure of a universal joint receiving working cylinder according to claim 6, wherein the direction adapting device and the universal swing rod share the same turning pair, and this turning pair is the first turning pair of the universal joint receiving connecting rod, and this turning pair has an axis perpendicular to the ground, and generally uses a slewing bearing, and the fixed disk of the slewing bearing is fixed to the foundation, and the support disk is fixedly connected on the movable disk, and the slewing bearing is a part of the base frame, and a base frame with one rotational degree of freedom is formed.

9. 7. The device for reducing positive pressure of a universal joint-receiving actuation cylinder according to claim 5 or 6, wherein the force generating device of the force applying device is one or a set of tension springs, and the force transmitting device of the force applying device is a universal joint, or a combination thereof.

10. 7. The device for reducing positive pressure of a universal joint receiving actuation cylinder according to claim 5 or 6, wherein the force transmission device of the force applying device is composed of a cable, a cable and a pulley, or a cable and a gearbox, and the force generating device of the force applying device is one of one or a set of tension springs, one or a set of torsion springs that generate tension force, an air spring with a gearbox, a swinging device or a counterweight, an electromagnetic spring, or a torque motor.

11. 9. The device for reducing positive pressure of a universal joint receiving actuation cylinder according to claim 7 or 8, wherein the force generating device of the force adding device is one or a set of torsion springs, which generate torque and are attached to a slewing bearing, with an axis that is horizontal and parallel to the axis of the horizontal shaft of the universal joint, and a connecting rod is connected to the universal joint receiving actuation cylinder via a leading pair.

12. 7. The device for reducing positive pressure in a universal joint receiving actuation cylinder according to claim 5 or 6, wherein the force generating device of the force adding device is one or a set of counterweights, which generate an anti-gravity moment and are connected to the actuation cylinder via the force transmitting device to generate an anti-gravity moment.

13. 6. The device for reducing positive pressure of a universal joint-received actuating cylinder according to claim 5, further comprising a parallel mechanism having at least one UPS-type branch, wherein the cylinder barrel of the leading joint of the UPS branch is connected to one end of a force-adding device to add an appropriate anti-gravity moment to the actuating cylinder, thereby forming a small lateral force parallel mechanism system.

14. A method for reducing positive pressure in a universal joint receiving actuation cylinder using the device for reducing positive pressure in a universal joint receiving actuation cylinder according to any one of claims 5 to 8, comprising: The number of positive pressure reducing devices of the universal joint receiving working cylinder is 2 to 6, and the universal swing rod device is a complete UPS branch; In the configuration of the parallel mechanism, a motion platform and a base platform are attached to the UPS branch; The method for reducing the positive pressure of a universal joint receiving actuation cylinder, wherein the UPS branch, the motion platform, and the base platform constitute a parallel mechanism, forming a slight positive pressure parallel mechanism system.

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