Device for connecting parallel joints

Abstract

A device for connecting parallel joints comprises a base and further comprises a plurality of driving assemblies arranged on the base. Each set of driving assembly comprises a connecting frame connected with the base, a cylinder body penetrating through the connecting frame and two piston rods extending into the two ends of the cylinder body respectively; the tail ends of the two piston rods are respectively connected with universal joints II; and the universal joint II is movably connected with the floating platform. The joints connected with the device move independently, completely independent motion control is achieved, the parallel joints can stably operate in complex motion scenes, risks caused by rope winding do not need to be worried about, the flexibility of motion control is improved, and the adaptability of the device in complex tasks is remarkably improved.

Description

Technical Field

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

[0002] With the rapid development of industrial technology, robots and robotic arms are increasingly used in industrial manufacturing, medical assistance, and service fields. Robots can be divided into ordinary serial robots and parallel robots according to the motion path. Among them, parallel robots contain multiple independent motion branches, and each end of the motion branch can be individually configured with an end effector (such as a mechanical gripper), which makes its motion mode diverse and the structure more rigid. In parallel robots, parallel joints and drive components are important components. The parallel joint connects the base and the end effector, and the drive component provides power to enable the end effector to move relative to the base.

[0003] For example, publication number CN201410700723.2 discloses a three-chain six-degree-of-freedom parallel mechanism with rope-driven joints, which consists of a fixed platform, a moving platform and three moving branches with exactly the same structure connecting the two platforms; wherein each moving branch from the fixed platform to the moving platform consists of a driving motor and a reducer device, a pulley, a driving rope, a rope-driven rotating joint, a rope-driven linear joint and a ball hinge; there are two sets of driving motors and reducer devices, which are respectively installed on motor seats fixedly connected to the fixed platform, and are respectively used to drive the rope-driven rotating joint and the rope-driven linear joint; 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 defect of the prior art is that the 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 mechanical 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 frequent movements or large load changes, resulting in difficulty in winding. 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 is. For each additional joint, an additional driving rope is 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 interference and entanglement between the driving ropes. 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 connections, 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. This 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: A device for parallel joint connection comprises a base and a plurality of drive assemblies arranged on the base; each set of the drive assemblies comprises a connecting frame connected to the base, a cylinder body passing through the connecting frame and two piston rods extending into the two ends of the cylinder body respectively; the ends of the two piston rods are respectively connected to universal joint 2; the universal joint 2 is movably connected to a floating platform.

[0007] The base is a fixed platform for the parallel joint device, and the drive assembly is directly arranged 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 includes a drive assembly, a universal joint 2 and a floating platform. The movements of the two joints do not affect each other and are only affected by the drive assembly. The connecting frame is embedded in the base and connected to the base, providing stable support and limit for the cylinder body, which helps 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 joints 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.

[0008] Preferably, the base comprises 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.

[0009] 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 drive device being directly installed 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. Preferably, the driving assembly comprises 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.

[0010] The cylinder and the piston rod perform relative telescopic movement through the pressure supplied by the hose, and then the floating platform performs pitch and yaw movement through the transmission of the universal joint 2. Traditional joint drives are independent of each other, especially pneumatic and hydraulic ones are difficult to achieve high synchronization due to the influence of pipeline length and bending, while conventional motors need to be controlled to achieve the movement synchronization of the equipment. When one of them fails, the movement of the other motor will be stuck. The driving force provided by the hose can make the floating platforms on both sides of the base move synchronously, and then make the parallel joints move synchronously. This transmission form can achieve synchronous movement without other redundant transmission components, which greatly simplifies the structure of the joint. The hose is interconnected with the inner cavity of each cylinder, the movement is interrelated, and the pressure of each moving point is consistent, so that the floating platform is more evenly stressed and the transmission is more stable, so it is easier to achieve the movement synchronization of the joints at both ends. The gas enters the inner cavity of the cylinder through the hose, driving the two piston rods to extend synchronously relative to the cylinder. Since the pressure provided by the hose can act on the piston rods on both sides at the same time, their movement speed and displacement are kept consistent, so that the floating platforms on both sides of the base can move synchronously. 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.

[0011] 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 both ends of the slewing drive cylinder respectively; the ends of the rotating shafts are movably connected to the center point of the floating platform via a universal joint.

[0012] 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 transmission is achieved 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 accuracy and extremely small errors. The transmission form of the slewing assembly can achieve synchronous motion without other redundant transmission components, which greatly simplifies the structure of the joint and avoids the complex transmission structure and synchronization problems caused by multi-point drive in traditional designs.

[0013] Preferably, the device comprises three sets of the driving components; the three connecting grooves are evenly distributed on the base plate.

[0014] The axis point of universal joint 1 is a fixed point and is located on the central axis of the base, and the axis point of universal joint 2 on the floating platform is a moving point. The transmission essence of the two joints of the device is the axis points of the two universal joints 2 and the axis point of universal joint 1. The three axis points determine a plane, that is, determine the posture of the floating platform in space. The movement of two of the drive components will change the positions of the two moving points of the floating platform, and the other drive component will follow the movement, the purpose is to make the force of the floating platform evenly distributed. The three connecting grooves are evenly distributed on the base plate, so that the drive components are symmetrically distributed in space. Symmetrically distributed drive components help ensure that the floating platform remains balanced during movement and avoid posture deviations caused by uneven force. The evenly distributed connecting grooves make the load borne by each drive component 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, evenly distributed drive components can work better together to achieve complex motion control. The three drive components work together through telescopic motion to achieve the pitch, yaw and rotation motion of the floating platform. The evenly distributed drive components can also control the attitude of the floating platform more accurately.

[0015] Preferably, the base further comprises 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.

[0016] 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 movement 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 facing 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.

[0017] Preferably, the base further comprises 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 substrate.

[0018] When the floating platform performs a rotational motion, the cylinder may become unstable due to a small movement or self-rotation. The setting of the spring can provide a reverse elastic force, effectively hindering the self-rotation of the cylinder, preventing the connecting frame from being separated from the connecting groove due to inertia, and improving the stability of the device under dynamic conditions. The elastic support of the spring can buffer the tiny vibrations and shakes generated by the cylinder during the movement, thereby improving the movement stability of the entire parallel joint connection device and reducing the risk of failure caused by structural looseness or component detachment.

[0019] Preferably, the floating platform comprises 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.

[0020] Since the swing plate of the floating platform is constrained by universal joint 2 and the driving assembly, the freedom of rotation around the central axis is constrained during pitch and yaw, and it cannot rotate with the drive of the slewing assembly. In order to overcome this defect, a rotating plate is set on the side of the swing plate away from universal joint 1. The rotating plate is only connected to universal joint 1 and can rotate with the transmission of universal joint 1.

[0021] 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 arranged in the connecting rod track.

[0022] By setting a ball at the end of the connecting frame and making it slide in the connecting rod channel of the base plate, the sliding friction between the connecting frame and the base plate is converted into rolling friction during the movement of the cylinder. The rolling contact mode of the ball effectively reduces the direct contact area between the cylinder and the base plate, and the friction coefficient of rolling friction is much lower than that of sliding friction, thereby significantly reducing the force generated by the cylinder on the base plate when it moves, and 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.

[0023] Preferably, the cylinder body is provided with two oil inlets.

[0024] 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.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In summary, in the traditional rope-driven parallel joint, the driving rope is prone to winding chaos, knotting or entanglement due to elastic deformation, complex path and other reasons. The present invention adopts a drive assembly composed of a cylinder body and a piston rod, and the drive assembly is arranged on the base, abandoning the rope drive mode. The linear motion of the piston rod in the cylinder body replaces the transmission of the rope, avoiding the length inconsistency problem caused by the elastic deformation of the rope, and fundamentally eliminating the possibility of winding chaos. In the case of frequent movement or large load changes, the device can always maintain a stable motion state, and there will be no motion jamming or failure caused by winding problems, which greatly improves the reliability and stability of the parallel joint. Since the movement of each piston rod is connected to the floating platform through universal joint 2, this connection method enables the linear motion of the piston rod to be flexibly transmitted to the floating platform, and the movements of each piston rod do not affect each other, which makes the movement of each joint no longer interfered by the motion state of other joints like rope drive. Therefore, each joint can independently complete its own motion task, improving the motion accuracy and flexibility of the parallel joint.

[0026] 2. In addition, the traditional rope-driven parallel joint requires the arrangement of multiple driving ropes in a limited space, and a complex path must be designed to guide the ropes, which makes the structure of the entire device more complicated and occupies a large space. However, the layout of the cylinder, piston rod, hose and other components of the present invention is more compact, and does not require a complex rope guiding path. Under the same function and range of motion, the parallel joint device is smaller in size and simpler in structure, and can better adapt to the working environment with limited space.

[0027] 3. The maintenance of rope-driven parallel joints is relatively complicated, requiring regular inspection and adjustment of rope tension, handling of winding problems, etc. However, the structure of the cylinder body, piston rod and other components of the present invention is relatively simple, and there is no complicated rope transmission system. During maintenance, only key components such as the cylinder body and piston rod need to be inspected and replaced. Therefore, the maintenance cost and maintenance time are reduced, and the service life and operating efficiency of the equipment are improved.

[0028] 4. The driving device of a general mechanical arm is installed at the joint, which makes its mass and volume relatively large, which is not conducive to the transmission of the structure. The driving assembly of the present invention is installed at the fixed platform base, which has low power consumption, high efficiency, fast response speed, and good compactness. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of the overall structure of Example 1; Figure 2 is a schematic diagram of the base structure of Example 1; Figure 3 is a control circuit schematic diagram of Example 1; Figure 4This is a simplified diagram illustrating the position of the singular point of Example 1.

[0030] in: 1. Driving assembly; 11. Cylinder body; 12. Piston rod; 13. Hose; 14. Connecting frame; 141. Cylinder seat; 142. Rotating rod; 15. Ball; 4. Rotation assembly; 41. Rotation drive cylinder; 42. Rotation shaft; 5. Floating platform; 51. Swinging plate; 52. Rotating plate; 6. Base; 61. Base plate; 611. Connecting rod; 62. Guide rail slider; 63. Connecting groove; 64. Spring; 65. Guide rail; 7. Universal joint one; 8. Universal joint two. DETAILED DESCRIPTION

[0031] In order to make the technical means, creative features, objectives and effects of the invention easier to understand, the invention is further described with reference to specific diagrams. However, the invention is not limited to the following implementation cases.

[0032] 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 as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical contents disclosed by the present invention.

[0033] Embodiment 1: like Figure 1 A device for parallel joint connection shown in the figure includes a base 6 and a plurality of drive assemblies 1 arranged on the base 6; each drive assembly 1 includes a connecting frame 14 connected to the base 6, a cylinder body 11 passing through the connecting frame 14 and two piston rods 12 respectively extending into the two ends of the cylinder body 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.

[0034] The base 6 is a 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 limiting 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.

[0035] The device of this embodiment includes three sets of driving components 1; three connecting grooves 63 are evenly distributed on the base plate 61, and the device has two three-degree-of-freedom joints symmetrically distributed with the base 6, which can achieve completely synchronous movement. The driving component 1 includes a hose 13 connected to the inner cavity of the cylinder body 11, and the gas enters the inner cavity of the cylinder body 11 through the hose 13 to drive the two piston rods 12 to extend synchronously relative to the cylinder body 11. It also includes a rotating component 4 arranged at the center of the base 6; the rotating component 4 includes a rotating drive cylinder 41 passing through the base 6 and two rotating shafts 42 extending into the two ends of the rotating drive cylinder 41 respectively; the end of the rotating shaft 42 is movably connected to the center point of the floating platform 5 through a universal joint 7.

[0036] The axis point of universal joint 1 7 is a fixed point and is located on the central axis of base 6, and 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. A total of three axis points determine a plane, that is, determine the posture of floating platform 5 in space. The movement of 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, the purpose is to make the force of floating platform 5 evenly distributed. 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 rotary motion is transmitted by the rotating shaft 42 and the universal joint to make the two sides perform synchronous rotary 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.

[0037] like Figure 2As shown, the base 6 includes a substrate 61 and a connecting groove 63 provided on the substrate 61; the connecting frame 14 is 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 in which the drive device is installed at the joint, the mass and volume of the joint are 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 1 in the connecting groove 63 of the base 6, the centralized installation of the drive device is achieved, and the increase in mass and volume caused by the direct installation of the drive device at the joint in the traditional robotic arm is avoided. 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. The three connection 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 to ensure that the floating platform 5 maintains balance during movement and avoids posture deviation caused by uneven force. The evenly distributed connection 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 control the posture of the floating platform 5 more accurately.

[0038] The cylinder 11 and the piston rod 12 perform relative telescopic movement through the pressure supplied by the hose 13, and then the floating platform 5 performs pitch and yaw movement through the transmission of the universal joint 8. Traditional joint drives are independent of each other, especially pneumatic and hydraulic ones are difficult to achieve high synchronization due to the influence of pipeline length and bending, while conventional motors need to be controlled to achieve the movement synchronization of the equipment. When one of them fails, it will cause the movement of the other motor to stagnate. The driving force provided by the hose 13 can make the floating platforms 5 on both sides of the base 6 to perform synchronous movement, and then make the parallel joints perform synchronous movement. This transmission form can achieve synchronous movement without other redundant transmission components, which greatly simplifies the structure of the joint. The hose 13 is interconnected with the inner cavity of each cylinder 11, the movement is interrelated, and the pressure of each moving point is consistent, so that the floating platform 5 is more evenly stressed and the transmission is more stable, so it is easier to achieve the movement synchronization of the joints at both ends. The 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 driving 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 of each moving point is consistent, so that the force of the entire mechanism is more uniform and the transmission is more stable, so it is easier to achieve the movement synchronization of the joints at both ends.

[0039] 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, thus ensuring that the floating platforms 5 on both sides always keep synchronization 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 other redundant transmission components, which greatly simplifies the structure of the joint and avoids the complex transmission structure and synchronization problems caused by multi-point drive in traditional designs.

[0040] 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 .

[0041] 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 a 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 caused by 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, ensures 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 facing 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.

[0042] 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 being separated from the connecting groove 63 due to inertia, and improving the stability of the device under dynamic conditions. The elastic support of the spring 64 can buffer the tiny vibrations and shakes 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.

[0043] The floating platform 5 includes a swing plate 51 and a rotating plate 52; the swing plate 51 is connected to the universal joint 28; the rotating plate 52 is connected to the universal joint 17; the swing plate 51 is arranged between the rotating plate 52 and the universal joint 17. Since the swing plate 51 of the floating platform 5 is constrained by the universal joint 28 and the driving assembly 1, the degree of freedom of rotation around the central axis during pitch and yaw is constrained, and it cannot rotate with the drive of the rotating assembly 4. In order to overcome this defect, a rotating plate 52 is arranged on the side of the swing plate 52 away from the universal joint 17, and the rotating plate 52 is only connected to the universal joint 17 and can rotate with the transmission of the universal joint 17.

[0044] The connecting frame 14 includes a connecting cylinder seat 141 connected to the cylinder body 11 and a rotating rod 142 connected to 141, and the base plate 61 includes a connecting rod track 611 connected to the rotating rod 142, and a ball 15 is arranged in the connecting rod track 611. By arranging the ball 15 at the end of the connecting frame 14 and making it slide in the connecting rod track 611 of the base plate 61, the sliding friction between the connecting frame 14 and the base plate 61 during the movement of the cylinder body 11 is converted into rolling friction. 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 rolling friction is much lower than that of sliding friction, thereby significantly reducing the force generated by the cylinder body 11 on the base plate 61 when moving, and 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.

[0045] The characteristic of an isosceles trapezoid is that the sum of the lengths of the upper and lower bases is always equal to twice the length of the line connecting the midpoints of the two waist sides. This characteristic also applies to three isosceles trapezoids evenly distributed in the space. Corresponding to the parallel joint, it is three times the distance between the axis points of the two universal joints 7.

[0046] According to 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, so the three drive components 1 can control the entire parallel joint with only three inlet and outlet hoses 13. Different from the traditional double-acting oil cylinder or air cylinder, three groups require six pipelines 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 cylinders or oil cylinders are not independent of each other, but are interrelated, so that the pressure can always remain 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.

[0047] Its control loop is as follows Figure 3 As shown, the solenoid valve 101 controls one of the drive components 1, the solenoid valve 2 102 controls the other drive component 1, and the switch valve 103 is normally open. When the solenoid valve 101 is connected and oil is flowing in from the left side, and the solenoid valve 2 102 is blocked, the oil cylinder of one drive component 1 is extended, and due to the transmission of the floating platform 50 and the universal joint, the oil cylinder of the following drive component 1 is contracted, and the oil in the oil chamber will be pressed out and flow to the right side of the solenoid valve 101 to return the oil, thereby realizing the forward movement of the pitch joint of the floating platform 5. When the solenoid valve 101 is connected and oil is flowing in from the right side, and the solenoid valve 2 102 is blocked, the oil cylinder of the following drive component 1 is extended, and due to the transmission of the floating platform 5 and the universal joint, the oil cylinder of the drive component 1 controlled by the solenoid valve 101 is contracted, and the oil in the oil chamber will be pressed out and flow to the left side of the solenoid valve 101 to return the oil, thereby realizing the reverse movement of the pitch motion of the floating platform 5. The same is true for the yaw joint.

[0048] like Figure 4As shown, when the two floating platforms 5 are parallel, it is a singular point, and the driving assembly 1 cannot constrain the posture of the joint. Taking one of the joints as an example, the rectangle surrounded by the four points A, B, C, and D is the singular point. Among them, A and B are the axis points of the two universal joints 7, and C and D are the axis points of the universal joint 2 8 connected to the piston rod 12 of the driving assembly 1. At this time, the mechanism is in an under-constrained state, and the mechanism will move due to external forces, such as the parallelogram surrounded by the four points A, B, C2, and D2.

[0049] Compared with the isosceles trapezoid formed by A, B, C1, and D1 in the normal motion state, one difference between the two is that in the isosceles trapezoid, the midpoint of the upper base is always on the symmetry plane. Therefore, the influence of the singular point on the joint movement can be solved by limiting the midpoint of the drive assembly 1 to always be located on the symmetry plane. Therefore, a connecting frame 14 is installed on the cylinder body 11 of the three drive assemblies 1 of the mechanism to ensure that the midpoint does not shift. However, when the mechanism is stationary at a certain position, the solenoid valve under the general transmission is in a blocked state to maintain the position, but at this time, the two piston rods 12 will lose the inlet pressure and will move relative to the cylinder body 11 as a whole if subjected to external force, so that the singular point cannot be avoided. Therefore, a switch valve 103 is added to the control loop. When the parallel joint is to stop at the singular point or a position near it, 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 bodies 11 of the two drive assemblies 1 will always be supplied with pressure to prevent the two piston rods 12 from moving relative to the cylinder body. The influence of singular points can be resolved through the above structure.

[0050] 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 it is not a 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.

[0051] Embodiment 2: 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 comprises a plurality of drive assemblies (1) arranged on the base (6); each set of the drive assemblies (1) comprises a connecting frame (14) connected to the base (6), a cylinder body (11) passing through the connecting frame (14), and two piston rods (12) extending into the two ends of the cylinder body (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 connection groove (63) provided on the base plate (61); the connection frames (14) are embedded in the connection grooves (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); 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 comprises a slewing assembly (4) arranged at the center of the base (6); the slewing assembly (4) comprises a slewing drive cylinder (41) passing through the base (6) and two rotating shafts (42) extending into the two ends of the slewing drive cylinder (41) respectively; the ends of the rotating shafts (42) are movably connected to the center point of the floating platform (5) via a universal joint (7).

5. The device for parallel joint connection according to claim 1, 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 4, characterized in that: The base (6) further comprises a guide rail (65) embedded in one of the connection 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 comprises a spring (64) embedded in the connection groove (63); one end of the spring (64) is connected to the connection frame (14), and the other end is connected to the base plate (61).

8. The device for parallel joint connection according to claim 1, 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 second universal joint (8); the rotating plate (52) is connected to the first universal joint (7); the swing plate (51) is arranged between the rotating plate (52) and the first universal joint (7).

9. The device for parallel joint connection according to claim 2, characterized in that: The connecting frame (14) comprises 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) comprises a connecting rod track (611) connected to the rotating rod (142); 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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