Device for parallel joint connection

Abstract

A device for parallel joint connections comprises a base and multiple drive assemblies mounted on the base. Each drive assembly comprises a connecting frame connected to the base, a cylinder extending through the connecting frame, and two piston rods extending into the cylinders at either end. The ends of the two piston rods are connected to universal joints 2, respectively. Universal joints 2 are movably connected to a floating platform. The joints connected by the device of the present invention move independently, achieving completely independent motion control. This allows the parallel joints to operate stably in complex motion scenarios without the risk of rope entanglement. This not only improves the flexibility of motion control but also significantly enhances the device's adaptability to complex tasks.

Description

Technical Field

[0001] The present invention relates to the technical field of parallel robots, and in particular to the design of a drive assembly for a parallel joint connection device. Background Art

[0002] With the rapid development of industrial technology, robots and robotic arms are increasingly being used in industrial manufacturing, medical assistance, and service sectors. Robots can be divided into conventional serial robots and parallel robots based on their motion paths. Parallel robots contain multiple independent motion branches, each of which can be equipped with an end effector (such as a mechanical gripper). This allows for diverse motion modes and a more rigid structure. Parallel joints and drive assemblies are key components of parallel robots. The parallel joint connects the base and the end effector, while the drive assembly provides power to move the end effector relative to the base.

[0003] For example, publication number CN201410700723.2 discloses a three-chain six-degree-of-freedom parallel mechanism with a rope-driven joint, which consists of a fixed platform, a moving platform and three moving branches with exactly the same structural form connecting the above two platforms; each moving branch from the fixed platform to the moving platform is composed of a drive motor and reducer device, a pulley, a drive rope, a rope-driven rotating joint, a rope-driven linear joint and a ball hinge; there are two sets of drive motors and reducer devices, which are respectively installed on motor seats fixed to the fixed platform, and are used to drive the rope-driven rotating joint and the rope-driven linear joint respectively; the upper end of the rope-driven linear joint in the moving branch is connected to the moving platform through a ball hinge, and the lower end of the rope-driven linear joint is connected to the fixed platform through a rope-driven rotating joint.

[0004] The drawback of the prior art is that rope-driven parallel joints are prone to difficulty in winding, which causes the movements of the joints to affect each other. Since the driving rope has a certain elasticity, it will stretch or shrink when subjected to force. When the robotic arm connected by the joints moves, the rope lengths of different joints change differently. The elastic deformation may cause the driving rope lengths to be inconsistent, which causes winding confusion. The loose driving ropes are prone to knotting or entanglement under conditions of frequent movement or large load changes, resulting in winding difficulties. Another reason is the complexity of the parallel joint multi-joint system. The more joints there are, the more complicated the path of the driving rope. For each additional joint, additional driving ropes are required to control its movement. These driving ropes need to be arranged and guided in a limited space. The complex path increases the possibility of the driving ropes interfering with each other and becoming entangled. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the present invention provides a device for parallel joint connection, in which the joints connected by the device move independently, realizing completely independent motion control, so that the parallel joints can operate stably in complex motion scenarios without worrying about the risks brought by rope entanglement. It not only improves the flexibility of motion control, but also significantly improves the adaptability of the device in complex tasks.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A device for parallel joint connection includes a base and multiple sets of drive assemblies arranged on the base; each set of the drive assemblies includes a connecting frame connected to the base, a cylinder passing through the connecting frame, and two piston rods extending into the two ends of the cylinder; the ends of the two piston rods are respectively connected to universal joint 2; the universal joint 2 is movably connected to the floating platform.

[0008] The base is the fixed platform of the parallel joint device, and the drive assembly is directly installed on the base. The floating platform is used to connect the end effector. The base divides the entire parallel joint device into two joints located on both sides of the base. Each joint contains a drive assembly, universal joint 2 and a floating platform. The movement of the two joints does not affect each other and is only affected by the drive assembly. The connecting frame is embedded in the base and connected to the base, providing stable support and positioning for the cylinder body, helping to maintain the stability and accuracy of the cylinder body during operation. The cylinder body passes through the connecting frame, and piston rods are connected to its two ends. The ends of the two piston rods are respectively connected to universal joint 2. The cylinder body and the piston rod perform relative telescopic movement through the supplied pressure, and then the floating platform is controlled to perform pitch and yaw movement through universal joint 2.

[0009] Preferably, the base includes a base plate and a connecting groove provided on the base plate; the connecting frames are embedded in the connecting groove and connected to the base plate.

[0010] The connecting groove is used to install the drive assembly. Compared with the traditional general robotic arm, the drive device is installed at the joint, which makes the mass and volume of the joint relatively large, which is not conducive to the transmission of the structure, and the power consumption is large, the efficiency is low, and the response speed is slow. By embedding the drive assembly in the connecting groove of the base, the centralized installation of the drive device is achieved, avoiding the increase in mass and volume caused by the direct installation of the drive device at the joint in the traditional robotic arm. The design significantly reduces the load at the joint and optimizes the transmission performance of the structure. Since the drive assembly is embedded in the base, its connection with the joint is more compact, reducing the influence of inertia during the transmission process, allowing the joint to respond faster, improving the response speed and dynamic performance of the entire robotic arm, simplifying the overall structure of the robotic arm, and improving the compactness of the device.

[0011] Preferably, the driving assembly includes a hose connected to the inner cavity of the cylinder body, and the gas enters the inner cavity of the cylinder body through the hose to drive the two piston rods to extend synchronously relative to the cylinder body.

[0012] Pressure supplied by a hose causes the cylinder and piston rod to extend and retract relative to each other, and universal joint 2 then drives the floating platform in pitch and yaw. Traditional joint drives are independent of each other, especially pneumatic and hydraulic ones, which are affected by pipeline length and bends, making high synchronization difficult. Conventional motors require control to synchronize the movement of the devices, and a failure in one motor can cause the other motor to stall. The driving force provided by the hose enables synchronized movement of the floating platforms on both sides of the base, and thus synchronized movement of the parallel joints. This transmission method achieves synchronized movement without requiring additional transmission components, significantly simplifying the joint structure. The hose is interconnected with the inner cavities of each cylinder, enabling interconnected movement and consistent pressure at all moving points, resulting in more uniform force on the floating platform and smoother transmission, making it easier to synchronize the movement of the joints at both ends. Gas enters the inner cavities of the cylinders through the hose, driving the two piston rods to extend synchronously relative to the cylinders. Because the pressure provided by the hose acts simultaneously on the piston rods on both sides, their speed and displacement are consistent, thus achieving synchronized movement of the floating platforms on both sides of the base. Synchronous motion can ensure the motion accuracy of the floating platform and parallel joints, better adapt to complex working environments and motion requirements, and avoid errors caused by inconsistent motion.

[0013] Preferably, it further comprises a slewing assembly arranged at the center of the base; the slewing assembly comprises a slewing drive cylinder passing through the base and two rotating shafts extending into the two ends of the slewing drive cylinder respectively; the ends of the rotating shafts are movably connected to the center point of the floating platform through a universal joint.

[0014] Through the design of the slewing assembly, the slewing motion of the floating platforms on both sides is driven by the same slewing drive cylinder, and power is transmitted through the rotating shaft and the universal joint. This ensures that the floating platforms on both sides always remain synchronized during the rotation process, with high motion precision and extremely small errors. The transmission form of the slewing assembly can achieve synchronous motion without any other redundant transmission components, greatly simplifying the structure of the joint and avoiding the complex transmission structure and synchronization problems caused by multi-point drive in traditional designs.

[0015] Preferably, the device comprises three sets of the driving components; the three connecting grooves are evenly distributed on the base plate.

[0016] The pivot point of universal joint 1 is a fixed point and lies on the central axis of the base. The pivot point of universal joint 2 on the floating platform is a moving point. The transmission mechanism of the two joints in the device is essentially the pivot points of universal joint 2 and universal joint 1. These three pivot points define a plane, which in turn determines the spatial position of the floating platform. The movement of two drive components changes the positions of the two moving points of the floating platform, while the third drive component performs a follow-up motion to ensure uniform force distribution on the floating platform. Three connecting slots are evenly distributed on the baseplate, creating a symmetrical spatial distribution of the drive components. This symmetrical distribution of the drive components helps ensure the floating platform maintains balance during movement, preventing posture deviations caused by uneven force distribution. The evenly distributed connecting slots ensure that each drive component bears a more even load. In practical applications, this effectively reduces the risk of local overload and improves the stability and reliability of the entire device. Furthermore, the evenly distributed drive components enable better coordination and achieve complex motion control. The three drive components work together through telescopic motion to achieve the pitch, yaw and rotation of the floating platform. The evenly distributed drive components can also control the attitude of the floating platform more accurately.

[0017] Preferably, the base further includes a guide rail embedded in one of the connecting grooves and a guide rail slider adapted to the guide rail; the cylinder body passes through the guide rail slider and is connected to the guide rail slider.

[0018] By arranging guide rails and guide rail sliders in the connecting groove, when the cylinder body generates inertial movement due to the telescopic movement of the piston rod, the guide rail slider can move in the corresponding direction on the guide rail, thereby releasing part of the force generated on the cylinder body. This design effectively reduces the risk of impact and damage to the drive assembly due to inertial movement, and improves the service life and reliability of the drive assembly. The setting of the guide rails and guide rail sliders provides a stable guide for the movement of the cylinder body, ensuring that the movement of the cylinder body is smoother and more precise, which helps to improve the motion stability of the entire parallel joint connection device, especially under high-speed or heavy-load conditions. The setting of the guide rails and guide rail sliders enables the drive assembly to better adapt to different working conditions and load changes. When faced with different operating tasks and working conditions, this design can ensure the stability and reliability of the drive assembly and improve the adaptability of the entire device.

[0019] Preferably, the base further includes a spring embedded in the connecting groove; one end of the spring is connected to the connecting frame, and the other end is connected to the base plate.

[0020] When the floating platform rotates, the cylinder may become unstable due to slight movement or self-rotation. The spring provides a counter-force, effectively inhibiting the cylinder's self-rotation and preventing the connecting frame from disengaging from the connection slot due to inertia, thereby improving the stability of the device under dynamic conditions. The spring's elastic support buffers the cylinder's minor vibrations and wobbles during movement, thereby improving the stability of the entire parallel joint connection and reducing the risk of failure due to structural loosening or component detachment.

[0021] Preferably, the floating platform includes a swing plate and a rotating plate; the swing plate is connected to the second universal joint; the rotating plate is connected to the first universal joint; and the swing plate is arranged between the rotating plate and the first universal joint.

[0022] Because the floating platform's swing plate is constrained by universal joint 2 and the drive assembly, its rotational freedom about its central axis is restricted during pitch and yaw, preventing it from rotating in response to the drive of the slewing assembly. To overcome this limitation, a rotating plate is installed on the side of the swing plate away from universal joint 1. This rotating plate is connected only to universal joint 1 and can rotate in response to the drive of universal joint 1.

[0023] Preferably, the connecting frame includes a cylinder seat connected to the cylinder body and a rotating rod connected to the cylinder seat, and the base plate includes a connecting rod track connected to the rotating rod, and a ball is provided in the connecting rod track.

[0024] By installing a ball bearing at the end of the connecting frame and having it slide within the connecting rod path of the baseplate, the sliding friction between the connecting frame and the baseplate is converted into rolling friction during the movement of the cylinder. The rolling contact of the ball bearing effectively reduces the direct contact area between the cylinder and the baseplate, and the coefficient of friction of rolling friction is much lower than that of sliding friction. This significantly reduces the force exerted on the baseplate during cylinder movement and significantly reduces wear between components. This extends the service life of the drive assembly, reduces the frequency of maintenance and replacement due to wear, and enhances the stability of the entire parallel joint connection device.

[0025] Preferably, the cylinder body is provided with two oil inlets.

[0026] By setting two oil inlets on the cylinder body, the cylinder body can be divided into two independent chambers, which control the joint movements on both sides respectively, so that the joints on both sides can move independently according to different task requirements, and can adapt to more complex motion scenarios and task requirements.

[0027] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0028] 1. In summary, in traditional rope-driven parallel joints, the drive rope is prone to winding chaos, knots, or entanglements due to elastic deformation and complex paths. However, the present invention utilizes a drive assembly consisting of a cylinder and piston rod, and positions the drive assembly on a base, eliminating the rope drive method. The linear motion of the piston rod within the cylinder replaces the rope transmission, avoiding the length inconsistency caused by elastic deformation of the rope and fundamentally eliminating the possibility of winding chaos. Under conditions of frequent movement or large load fluctuations, the device can maintain stable motion without experiencing motion freezes or failures caused by winding problems, significantly improving the reliability and stability of the parallel joint. Because the motion of each piston rod is connected to the floating platform via universal joint 2, this connection allows the linear motion of the piston rod to be flexibly transmitted to the floating platform, and the motion of each piston rod is independent of each other. This eliminates the interference of the motion of each joint with the motion of other joints, as is the case with rope-driven joints. As a result, each joint can independently complete its own motion task, improving the motion precision and flexibility of the parallel joint.

[0029] 2. Furthermore, conventional rope-driven parallel joints require multiple drive ropes to be arranged within a limited space, and complex rope routing must be designed. This makes the entire device complex and occupies a large space. However, the layout of the cylinder, piston rod, and hose components in this invention is more compact, and no complex rope routing is required. While maintaining the same functionality and range of motion, this parallel joint device is smaller and more streamlined, making it better suited to space-constrained work environments.

[0030] 3. Rope-driven parallel joints are complex to maintain, requiring regular inspection and adjustment of rope tension, as well as troubleshooting of winding issues. However, the cylinder, piston rod, and other components of the present invention are relatively simple in structure and lack a complex rope transmission system. Maintenance only requires inspection and replacement of key components like the cylinder and piston rod. This reduces maintenance costs and time, and increases the equipment's service life and operating efficiency.

[0031] 4. Conventional robotic arm drive devices are mounted at the joints, resulting in a relatively large mass and volume, which is not conducive to structural transmission. The drive assembly of the present invention is mounted at the fixed platform base, resulting in lower power consumption, higher efficiency, faster response speed, and a more compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of Example 1;

[0033] Figure 2 is a schematic diagram of the base structure of Example 1;

[0034] Figure 3 is a control loop schematic diagram of Example 1;

[0035] Figure 4 This is a simplified diagram illustrating the position of the singular point in Example 1.

[0036] in:

[0037] 1. Drive assembly; 11. Cylinder body; 12. Piston rod; 13. Hose; 14. Connecting frame; 141. Cylinder base; 142. Rotating rod; 15. Ball bearing;

[0038] 4. Rotation assembly; 41. Rotation drive cylinder; 42. Rotating shaft;

[0039] 5. Floating platform; 51. Swinging plate; 52. Rotating plate;

[0040] 6. Base; 61. Base plate; 611. Connecting rod; 62. Guide rail slider; 63. Connecting groove; 64. Spring; 65. Guide rail;

[0041] 7. Universal joint 1; 8. Universal joint 2. DETAILED DESCRIPTION

[0042] In order to make the technical means, creative features, objectives and effects of the invention easier to understand, the present invention is further described with reference to specific figures. However, the present invention is not limited to the following implementation cases.

[0043] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0044] Example 1:

[0045] like Figure 1 The device shown is for parallel joint connection, comprising a base 6 and a plurality of drive assemblies 1 arranged on the base 6; each drive assembly 1 comprises a connecting frame 14 connected to the base 6, a cylinder 11 passing through the connecting frame 14 and two piston rods 12 extending into the two ends of the cylinder 11; the ends of the two piston rods 12 are respectively connected to universal joints 8; the universal joints 8 are movably connected to the floating platform 5.

[0046] The base 6 is the fixed platform of the parallel joint device, and the drive assembly 1 is directly arranged on the base 6. The floating platform 5 is used to connect the end effector. The base 6 divides the entire parallel joint device into two joints located on both sides of the base 6. Each joint includes a drive assembly 1, a universal joint 8 and a floating platform 5. The movements of the two joints do not affect each other and are only affected by the drive assembly 1. The connecting frame 14 is embedded in the base 6 and connected to the base 6, providing stable support and positioning for the cylinder body 11, which helps to maintain the stability and accuracy of the cylinder body 11 during operation. The cylinder body 11 passes through the connecting frame 14, and its two ends are respectively connected to the piston rod 12. The ends of the two piston rods 12 are respectively connected to the universal joint 8. The cylinder body 11 and the piston rod 12 perform relative telescopic movement through the supplied pressure, and then the floating platform 5 is controlled to perform pitch and yaw movement through the universal joint 8.

[0047] This embodiment of the device includes three drive assemblies 1; three connecting slots 63 are evenly distributed on a base plate 61. The device features two three-degree-of-freedom joints symmetrically distributed around the base 6, enabling fully synchronized movement. The drive assembly 1 includes a hose 13 connected to the interior of the cylinder 11. Gas enters the interior of the cylinder 11 through the hose 13, driving two piston rods 12 to extend synchronously relative to the cylinder 11. It also includes a rotation assembly 4, located at the center of the base 6. The rotation assembly 4 includes a rotation drive cylinder 41 that passes through the base 6 and two rotating shafts 42 that extend into each end of the rotation drive cylinder 41. The ends of the rotating shafts 42 are movably connected to the center point of the floating platform 5 via a universal joint 7.

[0048] The axis point of universal joint 1 7 is a fixed point and is located on the central axis of base 6, while the axis point of universal joint 2 8 on floating platform 5 is a moving point. The transmission essence of the two joints of the device is the axis points of the two universal joints 2 8 and the axis point of universal joint 1 7. The three axis points determine a plane, that is, determine the posture of floating platform 5 in space. The movement of the two drive components 1 will change the positions of the two moving points of floating platform 5, and the other drive component 1 will follow the movement, with the purpose of evenly distributing the force on floating platform 5. In this transmission form, the two drive components 1 keep the two floating platforms 5 symmetrical relative to the central plane of base plate 61. The rotational motion is transmitted by the rotating shaft 42 and the universal joint to make the two sides perform synchronous rotational motion, thereby realizing the synchronous motion of floating platforms 5 at both ends, and in this transmission form, the synchronous motion can be realized without other redundant transmission components, which greatly simplifies the structure of the joint.

[0049] like Figure 2As shown, the base 6 includes a substrate 61 and a connecting groove 63 provided on the substrate 61; the connecting frames 14 are all embedded in the connecting groove 63 and connected to the substrate 61. The connecting groove 63 is used to install the drive assembly 1. Compared with the traditional general robotic arm, the drive device is installed at the joint, which makes the mass and volume of the joint relatively large, which is not conducive to the transmission of the structure, and the power consumption is large, the efficiency is low, and the response speed is also slow. By embedding the drive assembly 1 in the connecting groove 63 of the base 6, the centralized installation of the drive device is achieved, avoiding the increase in mass and volume caused by the direct installation of the drive device at the joint in the traditional robotic arm. The design significantly reduces the load at the joint and optimizes the transmission performance of the structure. Since the drive assembly 1 is embedded in the base 6, its connection with the joint is more compact, which reduces the inertia effect during the transmission process, enables the joint to respond faster, improves the response speed and dynamic performance of the entire robotic arm, simplifies the overall structure of the robotic arm, and improves the compactness of the device.

[0050] The three connecting grooves 63 are evenly distributed on the base plate 61, so that the drive components 1 are symmetrically distributed in space. The symmetrically distributed drive components 1 help ensure that the floating platform 5 maintains balance during movement and avoids posture deviation caused by uneven force. The evenly distributed connecting grooves 63 make the load borne by each drive component 1 more uniform. In practical applications, it can effectively reduce the risk of local overload and improve the stability and reliability of the entire device. At the same time, the evenly distributed drive components can work together better to achieve complex motion control. The three drive components 1 work together through telescopic motion to achieve the pitch, yaw and rotation motion of the floating platform 5. The evenly distributed drive components 1 can also more accurately control the posture of the floating platform 5.

[0051] The cylinder 11 and piston rod 12 move relative to each other through pressure supplied by the hose 13, and the floating platform 5 then moves in pitch and yaw through the transmission of the universal joint 8. Traditional joint drives are independent of each other, especially pneumatic and hydraulic ones, which are difficult to achieve high synchronization due to the influence of pipeline length and bending. Conventional motors require control to achieve device motion synchronization. When one motor fails, the other motor will cause the movement of the other motor to become stuck. The driving force provided by the hose 13 can make the floating platforms 5 on both sides of the base 6 move synchronously, and thus make the parallel joints move synchronously. This type of transmission can achieve synchronous motion without other redundant transmission components, greatly simplifying the structure of the joint. The hose 13 is interconnected with the inner cavity of each cylinder 11, and the motion is interrelated. The pressure at each moving point is consistent, making the force on the floating platform 5 more uniform and the transmission more stable, thus making it easier to achieve motion synchronization of the joints at both ends. Gas enters the inner cavity of the cylinder 11 through the hose 13, driving the two piston rods 12 to extend synchronously relative to the cylinder 11. Since the pressure provided by the hose 13 can act on the piston rods 12 on both sides at the same time, their movement speed and displacement are kept consistent, thereby achieving synchronous movement of the floating platforms 5 on both sides of the base 6. Synchronous movement can ensure the movement accuracy of the floating platform 5 and the parallel joint, better adapt to complex working environments and movement requirements, and avoid errors caused by inconsistent movement. The three drive components 1 of the device only need to be controlled by three external hoses 13, which reduces the number of hoses by half compared to traditional double-acting oil cylinders or air cylinders, and is more conducive to the line management and layout of the equipment. At the same time, the three cylinders or oil cylinders are interconnected, the movements are interrelated, and the pressure at each moving point is consistent, so that the force on the entire mechanism is more uniform and the transmission is more stable, thus making it easier to achieve movement synchronization of the joints at both ends.

[0052] Through the design of the slewing assembly 4, the slewing motion of the floating platforms 5 on both sides is driven by the same slewing drive cylinder 41, and power transmission is achieved through the rotating shaft 42 and the universal joint 7. This ensures that the floating platforms 5 on both sides always remain synchronized during the slewing process, with high motion accuracy and extremely small errors. The transmission form of the slewing assembly 4 can achieve synchronous motion without any other redundant transmission components, greatly simplifying the structure of the joint and avoiding the complex transmission structure and synchronization problems caused by multi-point drive in traditional designs.

[0053] The base 6 further includes a guide rail 65 embedded in one of the connecting grooves 63 and a guide rail slider 62 adapted to the guide rail 65 ; the cylinder body 11 passes through the guide rail slider 62 and is connected to the guide rail slider 62 .

[0054] By arranging the guide rail 65 and the guide rail slider 62 in the connecting groove 63, when the cylinder body 11 generates inertial movement due to the telescopic movement of the piston rod 12, the guide rail slider 62 can move in the corresponding direction on the guide rail 65, thereby releasing part of the force generated on the cylinder body 11. This design effectively reduces the risk of impact and damage to the drive assembly 1 due to inertial movement, and improves the service life and reliability of the drive assembly. The setting of the guide rail 65 and the guide rail slider 62 provides a stable guide for the movement of the cylinder body 11, ensuring that the movement of the cylinder body 11 is smoother and more precise, and helps to improve the motion stability of the entire parallel joint connection device, especially under high-speed or heavy-load conditions. The setting of the guide rail 65 and the guide rail slider 62 enables the drive assembly 1 to better adapt to different working conditions and load changes. When faced with different operating tasks and working conditions, this design can ensure the stability and reliability of the drive assembly 1 and improve the adaptability of the entire device.

[0055] The base 6 also includes a spring 64 embedded in the connecting groove 63; one end of the spring 64 is connected to the connecting frame 14, and the other end is connected to the base plate 61. When the floating platform 5 performs a rotational motion, the cylinder body 11 may become unstable due to a small movement or self-rotation. The setting of the spring 64 can provide a reverse elastic force, effectively hindering the self-rotation of the cylinder body 11, preventing the connecting frame 14 from detaching from the connecting groove 63 due to inertia, and improving the stability of the device under dynamic working conditions. The elastic support of the spring 64 can buffer the tiny vibrations and shaking generated by the cylinder body 11 during the movement, thereby improving the movement stability of the entire parallel joint connection device and reducing the risk of failure due to structural looseness or component detachment.

[0056] The floating platform 5 comprises a swing plate 51 and a rotating plate 52. The swing plate 51 is connected to universal joint 2 8, while the rotating plate 52 is connected to universal joint 1 7. The swing plate 51 is positioned between the rotating plate 52 and universal joint 1 7. Because the swing plate 51 of the floating platform 5 is constrained by universal joint 2 8 and the drive assembly 1, its rotational freedom about its central axis is restricted during pitch and yaw, preventing it from rotating in response to the drive of the rotary assembly 4. To overcome this limitation, a rotating plate 52 is positioned on the side of the swing plate 52 away from universal joint 1 7. The rotating plate 52 is connected only to universal joint 1 7 and can rotate in response to the drive of universal joint 1 7.

[0057] The connecting frame 14 includes a connecting cylinder seat 141 connected to the cylinder body 11 and a rotating rod 142 connected to 141. The base plate 61 includes a connecting rod channel 611 connected to the rotating rod 142, and the connecting rod channel 611 is provided with a ball 15. By providing the ball 15 at the end of the connecting frame 14 and making it slide within the connecting rod channel 611 of the base plate 61, the sliding friction between the connecting frame 14 and the base plate 61 is converted into rolling friction during the movement of the cylinder body 11. The rolling contact mode of the ball 15 effectively reduces the direct contact area between the cylinder body 11 and the base plate 61, and the friction coefficient of the rolling friction is much lower than that of the sliding friction, thereby significantly reducing the force generated by the cylinder body 11 on the base plate 61 during movement, significantly reducing the wear between the components, thereby extending the service life of the drive assembly, reducing the maintenance and replacement frequency caused by wear, and enhancing the stability of the entire parallel joint connection device.

[0058] The characteristic of an isosceles trapezoid is that the sum of the lengths of the upper and lower bases is always twice the length of the line connecting the midpoints of the two sides. This characteristic also applies to three isosceles trapezoids evenly spaced around the circumference in space. In this parallel joint, the distance between the axis points of the two universal joints 7 is three times the distance.

[0059] Based on the above characteristics, if the cylinder body 11 is driven by an oil cylinder, the total oil volume in the three oil cylinder chambers remains unchanged during the movement of the joint. Therefore, the three drive components 1 can control the entire parallel joint with only three inlet and outlet hoses 13. Unlike traditional double-acting oil or air cylinders, which require six pipes for control, this structure reduces the number of hoses 13 by half, which is more conducive to the line management and layout of the equipment. At the same time, the three air or oil cylinders are not independent of each other, but are interconnected, so that the pressure can always be consistent, which not only makes the force on the entire mechanism more uniform, but also makes it easier to achieve synchronous movement of the mechanism.

[0060] Its control loop is as follows Figure 3 As shown, solenoid valve 101 controls one of the drive components 1, solenoid valve 2 102 controls the other drive component 1, and switch valve 103 is normally open. When solenoid valve 101 is connected and oil is flowing in from the left side, and solenoid valve 2 102 is blocked, the oil cylinder of one drive component 1 extends. Due to the transmission of the floating platform 50 and the universal joint, the oil cylinder of the following drive component 1 contracts, and the oil in the oil chamber is pressed out and flows to the right side of solenoid valve 101 for oil return, thereby achieving the forward motion of the pitch joint of the floating platform 5. When solenoid valve 101 is connected and oil is flowing in from the right side, and solenoid valve 2 102 is blocked, the oil cylinder of the following drive component 1 extends. Due to the transmission of the floating platform 5 and the universal joint, the oil cylinder of the drive component 1 controlled by solenoid valve 101 contracts, and the oil in the oil chamber is pressed out and flows to the left side of solenoid valve 101 for oil return, thereby achieving the reverse motion of the pitch motion of the floating platform 5. The same applies to the yaw joint.

[0061] like Figure 4As shown, when the two floating platforms 5 are parallel, a singularity point occurs, and the drive assembly 1 is unable to constrain the joint's posture. Taking one joint as an example, the rectangle formed by points A, B, C, and D represents this singularity point. A and B are the axis points of universal joint 1 7, while C and D are the axis points of universal joint 2 8, which connects to the piston rod 12 of the drive assembly 1. At this point, the mechanism is in an underconstrained state and can move due to external forces, as shown in the parallelogram formed by points A, B, C2, and D2.

[0062] Compared to the isosceles trapezoid formed by A, B, C1, and D1 in a normal motion state, one difference between the two is that in the isosceles trapezoid, the midpoint of the upper base is always on the plane of symmetry. Therefore, the influence of the singularity on the joint movement can be resolved by limiting the midpoint of the drive assembly 1 to always be located on this plane of symmetry. Therefore, a connecting frame 14 is installed on the cylinder 11 of the three drive assemblies 1 of the mechanism to ensure that the midpoint does not shift. However, since the mechanism is stationary at a certain position, the solenoid valve under the transmission is generally in a closed state to maintain the position. However, at this time, due to the loss of inlet pressure, the two piston rods 12 will move as a whole relative to the cylinder 11 if subjected to external forces, thus making it impossible to avoid the singularity. Therefore, a switch valve 103 is added to the control circuit. When the parallel joint is to stop at or near the singularity point, the valve ports of the solenoid valve 101 and the solenoid valve 102 are opened, and the valve port of the switch valve 103 is closed. At this time, the cylinder 11 of the two drive assemblies 1 will always be supplied with pressure, thereby preventing the two piston rods 12 from moving relative to the cylinder. The influence of singular points can be resolved through the above structure.

[0063] It should be noted that in other postures, there is no singularity point, and it is not necessary to open the solenoid valve to supply pressure when the joint is stationary. In addition, in the singularity point posture, the connecting frame 14 is subjected to friction on the base plate 61. When the oil cylinder is extended and retracted, the driving force is perpendicular to the symmetry plane, and there is no component force parallel to the symmetry plane, which will form a dead point. Therefore, it is necessary to install a spring 64 to overcome the dead point, and the spring 64 can also prevent the self-rotation of the cylinder body 11 from causing the connecting frame 14 to disengage from the connecting groove 63. Furthermore, since there is no singularity point in other postures, there is no need to constrain the center position of the two drive components 1, so the connecting groove 63 can only exist in a small distance near the singularity point, and the groove width at other positions can be increased to avoid the influence of the friction between the connecting frame 14 and the connecting groove 63 on the movement of the mechanism.

[0064] Example 2:

[0065] In this embodiment, the cylinder body 11 is provided with two oil inlets and includes two independent cylinder chambers, so that each cylinder chamber controls the joint movement on both sides respectively. The postures of the floating platforms 5 on both sides of the base 6 are therefore different. The joints on both sides can move independently according to different task requirements, thus being able to adapt to more complex motion scenes and task requirements.

Claims

1. A device for parallel joint connection, comprising a base (6), characterized in that: It also includes multiple sets of drive assemblies (1) arranged on the base (6); each set of the drive assemblies (1) includes a connecting frame (14) connected to the base (6), a cylinder (11) passing through the connecting frame (14), and two piston rods (12) extending into the two ends of the cylinder (11); the ends of the two piston rods (12) are respectively connected to universal joints 2 (8); the universal joints 2 (8) are movably connected to the floating platform (5).

2. The device for parallel joint connection according to claim 1, characterized in that: The base (6) comprises a base plate (61) and a connecting groove (63) provided on the base plate (61); the connecting frames (14) are embedded in the connecting groove (63) and connected to the base plate (61).

3. The device for parallel joint connection according to claim 1, characterized in that: The driving assembly (1) comprises a hose (13) connected to the inner cavity of the cylinder (11), and gas enters the inner cavity of the cylinder (11) through the hose (13) to drive the two piston rods (12) to extend synchronously relative to the cylinder (11).

4. The device for parallel joint connection according to claim 1, characterized in that: It also includes a rotary assembly (4) arranged at the center of the base (6); the rotary assembly (4) includes a rotary drive cylinder (41) passing through the base (6) and two rotating shafts (42) extending into the two ends of the rotary drive cylinder (41); the ends of the rotating shafts (42) are movably connected to the center point of the floating platform (5) through a universal joint (7).

5. The device for parallel joint connection according to claim 2, characterized in that: The device comprises three sets of the driving components (1); the three connecting grooves (63) are evenly distributed on the base plate (61).

6. The device for parallel joint connection according to claim 2, characterized in that: The base (6) further comprises a guide rail (65) embedded in one of the connecting grooves (63) and a guide rail slider (62) adapted to the guide rail (65); the cylinder body (11) passes through the guide rail slider (62) and is connected to the guide rail slider (62).

7. The device for parallel joint connection according to claim 6, characterized in that: The base (6) further includes a spring (64) embedded in the connecting groove (63); one end of the spring (64) is connected to the connecting frame (14), and the other end is connected to the base plate (61).

8. The device for parallel joint connection according to claim 4, characterized in that: The floating platform (5) comprises a swing plate (51) and a rotating plate (52); the swing plate (51) is connected to the universal joint 2 (8); the rotating plate (52) is connected to the universal joint 1 (7); the swing plate (51) is arranged between the rotating plate (52) and the universal joint 1 (7).

9. The device for parallel joint connection according to claim 2, characterized in that: The connecting frame (14) includes a cylinder seat (141) connected to the cylinder body (11) and a rotating rod (142) connected to the cylinder seat (141); the base plate (61) includes a connecting rod track (611) connected to the rotating rod (142); and a ball (15) is provided in the connecting rod track (611).

10. The device for parallel joint connection according to claim 1, characterized in that: The cylinder body (11) is provided with two oil inlets.

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