End effector vibration control device and method based on a rope parallel mechanism

Abstract

The application provides a kind of end effector vibration control device and method based on rope parallel mechanism, it is related to vibration control field, device includes fixed platform, end effector, drive component, three-axis acceleration sensor, multiple rope components and rope measuring device, end effector includes platform and frame structure, frame structure is set on platform, drive component is set below platform, multiple rope components are installed on the both sides and top of frame structure, each rope component is provided with a rope measuring device, and the top of platform is provided with multiple three-axis acceleration sensors;Three-axis acceleration sensor and rope measuring device are used to measure the six-degree-of-freedom acceleration of end effector, including three direction linear acceleration and angular acceleration around three directions. It is adjusted to end effector by actively feeding back and controlling rope tension.

Description

Technical Field

[0001] This invention relates to the field of vibration control, and more specifically to a vibration control device and method for an end effector based on a rope parallel mechanism. Background Technology

[0002] The core components of a rope-driven parallel robot include a traction rope, an end effector platform, a drive unit, and a guide pulley system. The drive unit consists of a drum, a reducer, and a servo motor, and is fixed to the structural platform. In rope-driven parallel robots, flexible ropes are used instead of rigid links because the lightweight nature of the ropes allows the robot to move with extremely high acceleration and traverse very large workspaces. However, the elasticity of the ropes, their unidirectional force characteristics, and the dispersed drive unit pose challenges to the high-precision control of the end effector in rope-driven parallel robots.

[0003] The stiffness of a rope-driven parallel robot depends on both rope stiffness and rope length. In a large workspace, rope elasticity leads to a decrease in rope stiffness, further reducing the stiffness and positional accuracy of the end effector. Therefore, there is an urgent need to research a device capable of controlling the vibration of end effectors based on rope-driven parallel mechanisms, thereby improving the accuracy of the end effector. Summary of the Invention

[0004] The purpose of this invention is to provide a vibration control device and method for an end effector based on a rope parallel mechanism, which adjusts the end effector by actively feedback and controlling the rope tension. The device collects data through a triaxial accelerometer of the end effector and a rope measuring device, and calculates the vibration acceleration in all six degrees of freedom of the device to balance the vibration caused by the elasticity of the rope and its dependence on tension.

[0005] Specifically, the present invention provides a vibration control device for an end effector based on a rope parallel mechanism, comprising a controller, a fixed platform, an end effector, a drive assembly, a triaxial accelerometer, multiple rope assemblies, and a rope measuring device. The end effector includes a platform and a frame structure, with the frame structure positioned above the platform and the drive assembly positioned below the platform. Multiple rope assemblies are installed on both sides and the top of the frame structure, and each rope assembly is equipped with a rope measuring device. Multiple triaxial accelerometers are positioned on the top of the platform. The triaxial accelerometers and rope measuring devices are used to measure the six degrees of freedom acceleration of the end effector, including linear acceleration in three directions and angular acceleration around three directions. The drive assembly includes a motor mount, a servo motor, and a yaw mass. The motor mount is fixedly connected to the lower surface of the platform. The servo motor is mounted on the motor mount, and the yaw mass is disposed on the output shaft of the servo motor. The servo motor adjusts the yaw mass by receiving signals transmitted from the rope measuring device and the triaxial accelerometer, thereby generating a torque opposite to the vibration. The rope assembly includes a mounting plate, an adapter, and a rope. The mounting plate is fixedly mounted on the frame structure. The first end of the adapter is rotatably connected to the mounting plate. The second end of the adapter is connected to the second end of the rope measuring device. The first end of the rope measuring device is connected to the first end of the rope. The second end of the rope is connected to the fixed platform. The rope measuring device includes a first fixed connecting plate, a second fixed connecting plate, a first connecting seat, a second connecting seat, a damper, an encoder, a first connecting rod, and a second connecting rod. The rope passes through the first fixed connecting plate and is fixedly connected to it. The second fixed connecting plate is fixedly connected to the adapter. First connecting seats are respectively provided on both sides of the first fixed connecting plate, and second connecting seats are respectively provided on both sides of the second fixed connecting plate. The first end of the first connecting rod is rotatably connected to the first connecting seat, and the second end of the first connecting rod is connected to the first end of the second connecting rod. The second end of the second connecting rod is rotatably connected to the second connecting seat. A first gear is provided at the connection between the second connecting seat and the second fixed connecting plate, and a second gear that meshes with the first gear is provided at the connection between the second connecting seat and the second connecting rod. An encoder is provided on the outer wall of the second connecting rod to monitor the rotation of the second gear. The two ends of the damper are respectively connected to the first fixed connecting plate and the second fixed connecting plate. When the rope moves, the first link and the second link rotate, which in turn drives the first gear to rotate. The first gear further drives the second gear to rotate. The encoder measures the rotation of the second gear and transmits it as an output signal to the controller. The triaxial accelerometer measures the vibration acceleration in six directions and transmits it to the controller. The controller calculates the torque applied by the yaw mass based on the received signals and uses a servo motor to drive the yaw mass to add torque to the end effector for vibration control based on the calculation results.

[0006] Preferably, four triaxial accelerometers are provided, and twelve rope assemblies and twelve rope measuring devices are provided.

[0007] Preferably, the first fixed connecting plate and the second fixed connecting plate, the first connecting seat and the second connecting seat, and the first connecting rod and the second connecting rod have the same structure.

[0008] Preferably, the encoder is a magnetic encoder, and the magnetic encoder is perpendicularly connected to the gear.

[0009] Preferably, the drive assembly is provided in two sets, with two servo motors driving the yaw mass block to add torque to the end effector, thereby controlling the torque of the end effector.

[0010] Preferably, the first gear is an incomplete gear, and the second gear is a complete gear.

[0011] On the other hand, the present invention also provides a method for vibration control of an end effector vibration control device based on a rope parallel mechanism, which includes the following steps: S1. The encoder measures the rotation of the second gear and transmits it as an output signal to the controller; S2. A triaxial accelerometer measures vibration acceleration in six degrees of freedom. S3. Based on the signal measured by the encoder in step S1 and the vibration acceleration of the six degrees of freedom measured by the triaxial accelerometer in step S2, calculate the torque applied by the rope to the end effector and construct the dynamic equation of the end effector system in the initial state. S4. Construct the system dynamic equation of the end effector in the final state after the yaw mass is applied with torque, solve for the torque applied by the yaw mass, and use the servo motor to drive the yaw mass to add torque to the end effector for vibration control based on the solution.

[0012] Preferably, step S3 specifically includes the following sub-steps: S31. Calculate the length of the i-th rope:

[0013] in, Let be the length of the i-th rope. Let be the position vector of the connection point between the second end of the rope and the fixed platform. Let T be the position vector at the connection point between the first end of the rope and the end effector; T is the vector transpose. S32. For a given end effector pose ,Will Represented as:

[0014] in, This is the position vector of the end effector in the global coordinate system, including its x, y, and z coordinates in three-dimensional space; This is the offset from the platform center of the end effector to the position where the first end of the rope connects to the end effector. To be Rotation matrix from the fixed coordinate system of the end effector to the global coordinate system; S33, the unit vector along the i-th cable from the end effector to the fixed platform. Represented as: ; S34, Given Vector The vector contains The tension of the rope, among which express The tension of the rope, within the inertial frame, and the torque exerted by the rope on the center of mass of the end effector are:

[0015] in, The torque applied by the rope to the centroid of the end effector is a 6-dimensional vector, where the first three components represent forces Fx, Fy, and Fz, and the last three components represent moments Mx, My, and Mz about the x, y, and z axes; W is the torsion matrix of the rope, which is a 6xN matrix. Let be the tension vector of the rope; The torque matrix W is defined as follows: ; S35. Solve for the kinetic and potential energies of the end effector. The kinetic and potential energies of the end effector are respectively... and , represented as:

[0016]

[0017] in, It is the acceleration due to gravity. For the quality of the end effector, Let the moment of inertia matrix of the end effector mass be denoted as . It is the identity matrix. Let the generalized coordinate vector be the rope, and assuming the rope is massless, define the Lagrange equation as follows: ; S36. By deriving the Euler-Lagrange equations, the system dynamics equations of the end effector are obtained as follows:

[0018] in, The external torque applied to the center of mass of the end effector; The torque applied by the rope to the center of mass of the end effector.

[0019] Preferably, step S4 specifically includes the following sub-steps: S41. Define the Euler-Lagrange equations for the eccentric mass block after applying a torque as follows: ; S42. By deriving the Euler-Lagrange equations, the final system dynamics equations of the end effector are obtained as follows:

[0020] in, , , and The torque applied to the two oscillating masses; S43. Make the torque applied by the pendulum mass equal to the sum of the external torques: ; S44. Based on the yaw mass block obtained in step S43, apply a torque and use a servo motor to drive the yaw mass block to add a torque in the opposite direction to the end effector for vibration control.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention provides a vibration control device and method for an end effector based on a rope parallel mechanism. By actively feeding back and controlling the rope tension to adjust the end effector, the vibration of the end effector in the rope parallel mechanism can be controlled, thereby greatly improving the working accuracy of the end effector in the rope parallel mechanism.

[0022] (2) The present invention uses two methods of vibration reduction: active vibration reduction and passive vibration reduction. The device collects data through the three-axis acceleration sensor of the end effector and the rope measuring device. The vibration acceleration of the device in six degrees of freedom is calculated to balance the vibration caused by the elasticity of the rope and the fact that it is only subject to tension. The principle is that the rotational vibration can apply torque to the whole device through the reaction wheel to suppress the vibration. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the vibration control device for the end effector of the rope parallel mechanism of the present invention; Figure 2 A partially enlarged schematic diagram of the rope length measuring device in the vibration control device of the end effector of the rope parallel mechanism of the present invention; Figure 3 This invention provides a sensor array arrangement scheme for the vibration control device of the end effector of the rope parallel mechanism of the present invention. Figure 4a This is a partially enlarged schematic diagram of the oscillating mass block in the vibration control device of the end effector of the rope parallel mechanism of the present invention; Figure 4b for Figure 4a A schematic diagram of the AA cross-section; Figure 5 This is a schematic diagram of the method flow of the present invention; Figure 6 This is a schematic diagram of the operation of the vibration control device of the end effector of the rope parallel mechanism of the present invention; Figure 7 This is a schematic diagram illustrating the working principle of the present invention. Detailed Implementation

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0025] This invention provides a vibration control device and method for an end effector based on a rope parallel mechanism, used to control the vibration of the end effector in the rope parallel mechanism. The device collects data through a triaxial accelerometer of the end effector and a rope measuring device, and calculates the vibration acceleration in all six degrees of freedom of the device as a whole. This balances the vibration caused by the elasticity of the rope and its tensile properties. The principle is that rotational vibration can be suppressed by applying torque to the entire device through a reaction wheel.

[0026] Specifically, the present invention provides a vibration control device for an end effector based on a rope parallel mechanism, such as... Figure 1 up to Figure 4 and Figure 7 As shown, it includes a controller, a fixed platform, an end effector 5, a drive assembly, a triaxial accelerometer 11, multiple rope assemblies, and a rope measuring device 1. The end effector 5 includes a platform and a frame structure. The frame structure is located above the platform, and the drive assembly is located below the platform. Multiple rope assemblies are installed on both sides and the top of the frame structure. Each rope assembly is equipped with a rope measuring device 1. Multiple triaxial accelerometers are installed on the top of the platform. The triaxial accelerometers and rope measuring devices 1 are used to measure the six degrees of freedom acceleration of the end effector 5, including linear acceleration in three directions and angular acceleration around three directions. In this embodiment, four triaxial accelerometers are provided, and twelve rope assemblies and twelve rope measuring devices 1 are provided.

[0027] The drive assembly includes a motor mount 3, a servo motor 4, and a yaw mass 2. The motor mount 3 is fixedly connected to the lower surface of the platform. The servo motor 4 is mounted on the motor mount 3, and the yaw mass 2 is disposed on the output shaft of the servo motor 4. The servo motor 4 adjusts the yaw mass 2 by receiving signals transmitted from the rope measuring device 1 and the triaxial accelerometer 11, thereby generating a torque opposite to the vibration. In a specific embodiment, the drive assembly is provided in two sets, with two servo motors 4 driving the yaw mass 2 to add torque to the end effector 5, thereby controlling the torque of the end effector 5.

[0028] The rope assembly includes a mounting plate 6, an adapter 10, and a rope 9. The mounting plate 6 is fixedly mounted on the frame structure by means of bolts 8. The first end of the adapter 10 is rotatably connected to the mounting plate 6 by means of a pin 7. The second end of the rope 9 is connected to the fixed platform 12. The second end of the adapter 10 is connected to the second end of the rope measuring device 1, and the first end of the rope measuring device 1 is connected to the first end of the rope 9.

[0029] The rope measuring device 1 includes a first fixed connecting plate 103, a second fixed connecting plate 107, a first connecting seat 108, a second connecting seat 109, a damper 102, a first connecting rod 104, and a second connecting rod 105. Rope 9 passes through and is fixedly connected to the first fixed connecting plate 103. The second fixed connecting plate 107 is fixedly connected to the adapter 10. First connecting seats 108 are provided on both sides of the first fixed connecting plate 103. Second connecting seats 109 are provided on both sides of the second fixed connecting plate 107. The first end of the first connecting rod is rotatably connected to the first connecting seat 108. The second end of the first connecting rod 104 is connected to the first end of the second connecting rod 105. The second end of the second connecting rod 105 is rotatably connected to the second connecting seat 109. A first gear 101 is provided at the connection between the second connecting seat 109 and the second fixed connecting plate 107. A second gear 110 that meshes with the first gear is provided at the connection between the second connecting seat 109 and the second connecting rod. An encoder 106 is provided on the outer wall of the second connecting rod 105. The encoder 106 monitors the rotation of the second gear. The two ends of the damper 102 are connected to the first fixed connecting plate 103 and the second fixed connecting plate 107, respectively. The first connecting seat 108, the second connecting seat 109, the first connecting rod 104, and the second connecting rod 105 are each provided in two sets, and the two sets of components are arranged symmetrically.

[0030] The encoder 106 is a magnetic encoder, which is perpendicularly connected to the second gear 110. The first gear 101 is an incomplete gear, and the second gear 110 is a complete gear. When the rope moves, the first link and the second link rotate, which in turn drives the first gear 101 to rotate. The first gear 101 further drives the second gear 110 to rotate. The encoder 106 measures the rotation of the second gear 110 as an output signal, i.e., the elongation of the rope, and transmits it to the servo motor 4.

[0031] On the other hand, the present invention also provides a method for vibration control using an end effector vibration control device based on a rope parallel mechanism, such as... Figure 5 As shown, it includes the following steps: S1. The encoder measures the rotation of the second gear and transmits it as an output signal to the controller.

[0032] S2, a triaxial accelerometer, measures vibration acceleration in six degrees of freedom.

[0033] S3. Based on the signals measured by the encoder in step S1 and the vibration accelerations in six directions measured by the triaxial accelerometer in step S2, calculate the torque exerted by the rope on the end effector and construct the dynamic equations of the end effector system in the initial state. Specifically, this includes the following sub-steps: S31. Calculate the length of the i-th rope:

[0034] in, Let be the length of the i-th rope. Let be the position vector of the connection point between the second end of the rope and the fixed platform. Let T be the position vector at the connection point between the first end of the rope and the end effector; T is the vector transpose.

[0035] S32. For a given end effector pose ,Will Represented as:

[0036] in, This is the position vector of the end effector in the global coordinate system, including its x, y, and z coordinates in three-dimensional space; This is the offset from the platform center of the end effector to the position where the first end of the rope connects to the end effector. To be The rotation matrix that transforms the fixed coordinate system of the end effector to the global coordinate system.

[0037] S33, the unit vector along the i-th cable from the end effector to the fixed platform. Represented as: .

[0038] S34, Given Vector The vector contains The tension of the rope, among which express The tension of the rope, within the inertial frame, and the torque exerted by the rope on the center of mass of the end effector are:

[0039] in, The torque applied by the rope to the centroid of the end effector is a 6-dimensional vector, where the first three components represent forces Fx, Fy, and Fz, and the last three components represent moments Mx, My, and Mz about the x, y, and z axes; W is the torsion matrix of the rope, which is a 6xN matrix. Let be the tension vector of the rope.

[0040] The torque matrix W is defined as follows: .

[0041] S35. Solve for the kinetic and potential energies of the end effector. The kinetic and potential energies of the end effector are respectively... and , is represented as:

[0042]

[0043] in, It is the acceleration due to gravity. For the quality of the end effector, Let the moment of inertia matrix of the end effector mass be denoted as . It is the identity matrix. Let the generalized coordinate vector be the rope, and assuming the rope is massless, define the Lagrange equation as follows: .

[0044] S36. By deriving the Euler-Lagrange equations, the system dynamics equations of the end effector are obtained as follows:

[0045] in, The external torque applied to the center of mass of the end effector; The torque applied by the rope to the center of mass of the end effector.

[0046] in, K is the elastic modulus of the rope.

[0047] J is the Jacobian matrix of the end effector.

[0048] In this step, the length of each rope is measured by the rope measuring device 1 and compared with the length of the rope under no external force. The elongation of the rope is calculated by comparing the two, and the rope tension is obtained. Based on the position and attitude information of the end effector, the torque on the actuator is calculated.

[0049] For any planar CDPR configuration, at any point within the planar workspace The nonplanar components must be To effectively regulate the planar dynamics of the proposed planar CDPR, the basic idea is to add an inertial load to the moving platform. Any force applied to this load will generate a reaction force of equal magnitude and opposite direction on the platform.

[0050] The rigid pendulum is coupled to the motor shaft on the moving platform. The imbalance of the pendulum causes the motor shaft to be subjected to torque and tangential reaction force. Different installation positions generate additional secondary reaction torque.

[0051] Add two parallel lines to the platform The yaw mass blocks on the shaft can generate a torque that is only about the axis while maintaining the original coupling torque. The pure torque of the shaft.

[0052] S4. Construct the system dynamic equation of the end effector in the final state after the yaw mass is applied with torque, solve for the torque applied by the yaw mass, and use the servo motor to drive the yaw mass to add torque to the end effector for vibration control based on the solution.

[0053] This step includes the following sub-steps: S41. Define the Euler-Lagrange equations for the eccentric mass block after applying a torque as follows: .

[0054] In the formula, These represent the kinetic and potential energies of the two oscillating masses, respectively.

[0055] S42. By deriving the Euler-Lagrange equations, the final system dynamics equations of the end effector are obtained as follows:

[0056] in, , , and The torque applied to the two oscillating masses.

[0057] S43. Make the torque applied by the pendulum mass equal to the sum of the external torques: .

[0058] S44. Apply torque to the yaw mass block based on the solution obtained in step S43, and use the servo motor to drive the yaw mass block to add torque to the end effector for vibration control.

[0059] In this step, the kinetic and potential energy of the i-th pendulum mass are defined by the following formula:

[0060] in, Indicates the first The swing velocity of a pendulum mass; Indicates the first The mass of a pendulum mass block. This represents the moment of inertia of the yaw mass. This represents the angular velocity of the yaw mass. It is an identity matrix.

[0061] The swing velocity of the eccentric mass can be calculated using the following formula: .

[0062] In this formula, firstly, the cross product of the platform's angular velocity and the vector pointing from the platform's origin to the center of rotation of the pendulum mass is calculated, resulting in a vector representing the change in the velocity of the pendulum mass's center of mass caused by the platform's rotation. Next, a rotation matrix is ​​used to transform the cross product from the platform's fixed coordinate system to the global coordinate system. Then, the cross product of the pendulum mass's angular velocity and its length is calculated, resulting in a vector representing the change in the velocity of the pendulum mass's center of mass caused by its own rotation. Again, a rotation matrix is ​​used to transform the cross product from the pendulum actuator's local coordinate system to the global coordinate system. Finally, these results are summed to obtain the linear velocity of the pendulum mass's center of mass in the global coordinate system. Specific Implementation like Figure 1 As shown, the vibration control device for the end effector of the rope parallel mechanism provided by the present invention includes a servo motor 4, a yaw mass block 2, a triaxial accelerometer 11, and a rope measuring device 1. The yaw mass block 2 is fixed to the drive shaft of the servo motor 4 by set screws. The axis of the servo motor 4 is coplanar with the plane of symmetry of the device, and the two servo motors 4 are arranged back-to-back. The servo motors 4 are fixed to a motor base 3, which is fixed to the platform, by four bolts and nuts. The movement of the servo motors is controlled by a processor or controller. The controller receives instructions from the processor and drives the servo motor 4 according to the eccentric mass motion command value, further driving the eccentric mass block 2 to move. The axes of the two eccentric mass blocks are collinear. After receiving the measured vibration acceleration in six directions, the signal is immediately sent to the servo motor 4, driving the yaw mass block 2 to apply a torque in the opposite direction to the device, thereby reducing the vibration acceleration when the device moves in the six degrees of freedom.

[0064] Four capacitive triaxial accelerometers 11 are transmitted through, as shown in... Figure 3 The device is mounted on a frame and measures the vibration acceleration of the entire device in six directions, including linear acceleration in three directions and angular acceleration around three directions. (The four triaxial accelerometers are arranged on one side of the absolute coordinate system, while the other side is not arranged. This facilitates the design of the rigid support in the six-degree-of-freedom acceleration measurement device and the installation of the device in the actual test environment.) The rope is finally connected to the end effector through the rope measuring device 1. The connection between the rope measuring device 1 and the rope measuring device 1 is a roller connected to the rope measuring device 1. The roller and the rope measuring device 1 are connected by a pin, and the fixed end is connected by fasteners such as bolts and nuts.

[0065] like Figure 2 As shown, the rope length measuring device 1 includes a first fixed connecting plate 103, a second fixed connecting plate 107, a first connecting seat 108, a second connecting seat 109, a damper 102, a first connecting rod 104, and a second connecting rod 105. Rope 9 passes through and is fixedly connected to the first fixed connecting plate 103. The second fixed connecting plate 107 is fixedly connected to the adapter 10. First connecting seats 108 are provided on both sides of the first fixed connecting plate 103. Second connecting seats 109 are provided on both sides of the second fixed connecting plate 107. The first end of the first connecting rod is rotatably connected to the first connecting seat 108. The second end of the first connecting rod 104 is connected to the first end of the second connecting rod 105. The second end of the second connecting rod 105 is rotatably connected to the second connecting seat 109. A first gear 101 is provided at the connection between the second connecting seat 109 and the second fixed connecting plate 107. A second gear 110 that meshes with the first gear is provided at the connection between the second connecting seat 109 and the second connecting rod. An encoder 106 is provided on the outer wall of the second connecting rod 105. The encoder 106 monitors the rotation of the second gear. The two ends of the damper 102 are connected to the first fixed connecting plate 103 and the second fixed connecting plate 107, respectively. The first connecting seat 108, the second connecting seat 109, the first connecting rod 104, and the second connecting rod 105 are each provided in two sets, and the two sets of components are arranged symmetrically.

[0066] The device extends along its centerline via a rope. A damper between the devices mitigates instantaneous rope length changes. This rope elongation is converted into relative rotation of the first and second links, ultimately manifested through the mutual rotation of the first and second gears. A magnetic absolute rotary encoder measures the rotation angle of the magnetized gears to calculate the rope elongation. The calculated rotation between the ropes controls the servo motor shaft, which in turn drives two collinear oscillating mass blocks to generate a counter-torque (obtainable by adjusting amplitude and frequency) to counteract the device's instantaneous vibration. Furthermore, a wind force and direction sensing unit is attached to the end effector to stabilize it in windy conditions and address rope sagging, improving the environmental adaptability of the end effector vibration control device. The wind force and direction sensing unit adjusts the rope tension based on wind conditions and sends this information to the integrated management unit. By considering vibration acceleration in six directions, the unit adjusts the rope length and tension to maintain the device in a state of force balance.

[0067] like Figure 3 The diagram shows an array of four triaxial accelerometers on an end effector. The arrangement shown in the diagram allows for the measurement of vibration acceleration in three directions and six degrees of freedom of the end effector.

[0068] like Figure 4a and Figure 4b The diagram shows two oscillating mass blocks 2, which are contained in the same plane of rotation and have different oscillation phases, frequencies, or amplitudes around a common axis of rotation. Each oscillating mass block 2 includes an oscillating block 21 and an oscillating axis 22.

[0069] Figure 6 The diagram below illustrates the overall workflow of the device in a specific application of this invention. The device measures the vibration degrees of freedom in six directions, calculates the required torque, adjusts the servo motor via a controller to drive the oscillation of the yaw mass block, generating a torque in the opposite direction to the vibration, and then measures the vibration.

[0070] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A vibration control device for an end effector based on a rope parallel mechanism, characterized in that: It includes a controller, a fixed platform, an end effector, a drive assembly, a triaxial accelerometer, multiple rope assemblies, and a rope measuring device. The end effector includes a platform and a frame structure, with the frame structure positioned above the platform and the drive assembly positioned below the platform. Multiple rope assemblies are installed on both sides and the top of the frame structure, and each rope assembly is equipped with a rope measuring device. Multiple triaxial accelerometers are mounted on the top of the platform. The triaxial accelerometers and rope measuring devices are used to measure the six degrees of freedom acceleration of the end effector, including linear acceleration in three directions and angular acceleration around three directions. The drive assembly includes a motor mount, a servo motor, and a yaw mass. The motor mount is fixedly connected to the lower surface of the platform. The servo motor is mounted on the motor mount, and the yaw mass is disposed on the output shaft of the servo motor. The servo motor receives signals transmitted from the rope measuring device and the triaxial accelerometer through the controller to adjust the yaw mass, thereby generating a torque opposite to the vibration. The rope assembly includes a mounting plate, an adapter, and a rope. The mounting plate is fixedly mounted on the frame structure. The first end of the adapter is rotatably connected to the mounting plate. The second end of the adapter is connected to the second end of the rope measuring device. The first end of the rope measuring device is connected to the first end of the rope. The second end of the rope is connected to the fixed platform. The rope measuring device includes a first fixed connecting plate, a second fixed connecting plate, a first connecting seat, a second connecting seat, a damper, an encoder, a first connecting rod, and a second connecting rod. The rope passes through the first fixed connecting plate and is fixedly connected to it. The second fixed connecting plate is fixedly connected to the adapter. First connecting seats are respectively provided on both sides of the first fixed connecting plate, and second connecting seats are respectively provided on both sides of the second fixed connecting plate. The first end of the first connecting rod is rotatably connected to the first connecting seat, and the second end of the first connecting rod is connected to the first end of the second connecting rod. The second end of the second connecting rod is rotatably connected to the second connecting seat. A first gear is provided at the connection between the second connecting seat and the second fixed connecting plate, and a second gear that meshes with the first gear is provided at the connection between the second connecting seat and the second connecting rod. An encoder is provided on the outer wall of the second connecting rod to monitor the rotation of the second gear. The two ends of the damper are respectively connected to the first fixed connecting plate and the second fixed connecting plate. When the rope moves, the first link and the second link rotate, which in turn drives the first gear to rotate. The first gear further drives the second gear to rotate. The encoder measures the rotation of the second gear and transmits it as an output signal to the controller. The triaxial accelerometer measures the vibration acceleration in six directions and transmits it to the controller. The controller calculates the torque applied by the yaw mass based on the received signals and uses a servo motor to drive the yaw mass to add a reverse torque to the end effector for vibration control based on the calculation results.

2. The end effector vibration control device based on a rope parallel mechanism according to claim 1, characterized in that: The triaxial accelerometer is provided with four units, and the rope assembly and rope measuring device are each provided with twelve units.

3. The end effector vibration control device based on a rope parallel mechanism according to claim 1, characterized in that: The first fixed connecting plate and the second fixed connecting plate, the first connecting seat and the second connecting seat, and the first connecting rod and the second connecting rod all have the same structure.

4. The end effector vibration control device based on a rope parallel mechanism according to claim 3, characterized in that: The encoder is a magnetic encoder, and the magnetic encoder is perpendicularly connected to the second gear.

5. The end effector vibration control device based on a rope parallel mechanism according to claim 1, characterized in that: The drive assembly consists of two sets, with two servo motors driving the yaw mass block to add torque to the end effector, thereby controlling the torque of the end effector.

6. The end effector vibration control device based on a rope parallel mechanism according to claim 1, characterized in that: The first gear is an incomplete gear, and the second gear is a complete gear.

7. A method for vibration control using the end effector vibration control device based on a rope parallel mechanism as described in any one of claims 1-6, characterized in that: It includes the following steps: S1. The encoder measures the rotation of the second gear and transmits it as an output signal to the controller; S2. A triaxial accelerometer measures vibration acceleration in six degrees of freedom. S3. Based on the signal measured by the encoder in step S1 and the vibration acceleration of the six degrees of freedom measured by the triaxial accelerometer in step S2, calculate the torque applied by the rope to the end effector and construct the dynamic equation of the end effector system in the initial state. S4. Construct the system dynamic equation of the end effector in the final state after the yaw mass is applied with torque, solve for the torque applied by the yaw mass, and use the servo motor to drive the yaw mass to add torque to the end effector for vibration control based on the solution.

8. The method for vibration control of the end effector vibration control device based on the rope parallel mechanism according to claim 7, characterized in that: Step S3 specifically includes the following sub-steps: S31. Calculate the length of the i-th rope: ； in, Let be the length of the i-th rope. Let be the position vector of the connection point between the second end of the rope and the fixed platform. Let T be the position vector at the connection point between the first end of the rope and the end effector; T is the vector transpose. S32. For a given end effector pose ,Will Represented as: ； in, This is the position vector of the end effector in the global coordinate system, including its x, y, and z coordinates in three-dimensional space; This is the offset from the platform center of the end effector to the position where the first end of the rope connects to the end effector. To be Rotation matrix from the fixed coordinate system of the end effector to the global coordinate system; S33, the unit vector along the i-th cable from the end effector to the fixed platform. Represented as: ； S34, Given Vector The vector contains The tension of the rope, among which express The tension of the rope, within the inertial frame, and the torque exerted by the rope on the center of mass of the end effector are: ； in, The torque applied by the rope to the centroid of the end effector is a 6-dimensional vector, where the first three components represent forces Fx, Fy, and Fz, and the last three components represent moments Mx, My, and Mz about the x, y, and z axes; W is the torsion matrix of the rope, which is a 6xN matrix. Let be the tension vector of the rope; The torque matrix W is defined as follows: ； S35. Solve for the kinetic and potential energies of the end effector. The kinetic and potential energies of the end effector are respectively... and , is represented as: ； in, It is the acceleration due to gravity. For the quality of the end effector, Let the moment of inertia matrix of the end effector mass be denoted as . It is the identity matrix. Let the generalized coordinate vector be the rope, and assuming the rope is massless, define the Lagrange equation as follows: ； S36. By deriving the Euler-Lagrange equations, the system dynamics equations of the end effector are obtained as follows: ； in, The external torque applied to the center of mass of the end effector; The torque applied by the rope to the center of mass of the end effector.

9. The method for vibration control of the end effector vibration control device based on the rope parallel mechanism according to claim 8, characterized in that: Step S4 specifically includes the following sub-steps: S41. Define the Euler-Lagrange equations for the eccentric mass block after applying a torque as follows: ； S42. By deriving the Euler-Lagrange equations, the final system dynamics equations of the end effector are obtained as follows: ； in, , , and The torque applied to the two oscillating masses; S43. Make the torque applied by the pendulum mass equal to the sum of the external torques: ； S44. Based on the yaw mass block obtained in step S43, apply a torque and use a servo motor to drive the yaw mass block to add a torque in the opposite direction to the end effector for vibration control.

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