A control method for a three-degree-of-freedom platform on a horizontal plane

Abstract

The present invention provides a control method for a three-degree-of-freedom platform on a horizontal plane, which relates to the technical field of automatic control. The method includes reading the cylinder length information of each group of electric cylinders through an absolute encoder and inputting it into the platform position inverse resolver to obtain the initial position and angle of the floating platform after power-on; receiving a speed control instruction and performing acceleration and deceleration filtering processing to obtain an actual speed control instruction; inputting the actual speed control instruction into the platform position forward resolver, and combining the initial position and angle of the floating platform to obtain the target extension length of each group of electric cylinders; generating a target length instruction according to the target extension length of each group of electric cylinders and sending it to the corresponding servo driver to control the servo driver to track the target length instruction in real time; and circularly executing the control process of the servo driver until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is satisfied, so as to perform high-precision and stable three-degree-of-freedom motion control on the platform.

Description

Technical Field

[0001] The present invention relates to the field of automatic control technology, and particularly to a control method for a three-degree-of-freedom platform on a horizontal plane. Background Art

[0002] In the fields of modern industrial production, scientific research experiments, etc., it is usually necessary to precisely control the position and angle of an object within a horizontal plane.

[0003] Currently, the existing platform control methods have certain limitations in terms of accuracy, response speed, and control complexity. This method cannot quickly and accurately obtain the initial position of the platform, which may lead to a positioning deviation at the control startup stage. And during the motion control process, it is difficult for this method to achieve precise synchronous control of multiple degrees of freedom according to real-time instructions, which may affect the overall performance and working efficiency of the equipment.

[0004] Therefore, it is necessary to provide a control method for a three-degree-of-freedom platform on a horizontal plane to solve the above technical problems. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a control method for a three-degree-of-freedom platform on a horizontal plane, which is used to solve the deficiencies in the determination of the initial position, the calculation of the target position, and the synchronous motion control of the electric cylinders in the existing platform motion control methods, and the problem that the platform cannot be subjected to high-precision and stable three-degree-of-freedom motion control.

[0006] The control method for a three-degree-of-freedom platform on a horizontal plane provided by the present invention includes:

[0007] Read the electric cylinder length information of each group of electric cylinders through an absolute encoder and input it to the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on;

[0008] Receive a speed control instruction and perform acceleration and deceleration filtering processing to obtain an actual speed control instruction;

[0009] Input the actual speed control instruction to the platform position forward solver, and combine the initial position and angle of the floating platform to obtain the target extension length of each group of electric cylinders;

[0010] Generate a target length instruction according to the target extension length of each group of electric cylinders and send it to the corresponding servo driver to control the servo driver to track the target length instruction in real time;

[0011] Loop and execute the control process of the servo driver until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met.

[0012] Preferably, the base platform and the floating platform are connected by 4 electric cylinders.

[0013] Preferably, the electric cylinder length information of each electric cylinder is read by an absolute encoder and input into the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on, specifically including:

[0014] After power-on, the electric cylinder length information of the i-th electric cylinder is read by the absolute encoder ;

[0015] Set the floating platform as u, the base platform as b, and the coordinates of the floating platform in the base coordinate system at the initial moment as , and the angle as . Obtain the hinge point of the floating platform and the i-th electric cylinder, and its coordinates in the floating coordinate system are . After the following coordinate transformation, the coordinates of the hinge point of the floating platform and the i-th electric cylinder at the initial moment in the base coordinate system are :

[0016] Obtain the coordinates of the hinge point of the base platform and the i-th electric cylinder in the base coordinate system as , and construct a loss function as follows:

[0017] Calculate the derivative of the loss function as , , .

[0018] Preferably, select a step size parameter , and update the coordinates and angle of the floating platform in the base coordinate system at the initial moment according to the following formula to obtain the corresponding coordinate estimate and angle estimate :

[0019] Repeat the update step of the coordinates and angle of the floating platform in the base coordinate system until the loss function is less than the preset loss value, and output the coordinate estimate and angle estimate of the floating platform in the base coordinate system, that is, the initial position of the floating platform after power-onand angle .

[0020] Preferably, inputting the actual speed control instruction into the platform position forward resolver, and combining the initial position and angle of the floating platform to obtain the target extension lengths of each group of electric cylinders specifically includes:

[0021] Receiving the actual speed control instruction 、 、 ;

[0022] Setting the control period as T, and combining the initial position and angle of the floating platform to obtain the target position and angle of the floating platform after the end of one control period as follows:

[0023] Based on the coordinates of the hinge point between the floating platform and the i-th group of electric cylinders in the floating coordinate system , and combining the target position and angle of the floating platform, after the following coordinate system transformation, the coordinates of the hinge point between the floating platform and the i-th group of electric cylinders in the base coordinate system after the end of one control period are :

[0024] Combining the coordinates of the hinge point between the base platform and the i-th group of electric cylinders in the base coordinate system , calculating the target extension length of the i-th group of electric cylinders after the end of one control period as follows:

[0025] .

[0026] Preferably, based on the target length instruction, the servo driver adjusts the floating platform in three degrees of freedom according to the cyclic synchronous position mode.

[0027] A control system for a three-degree-of-freedom platform on a horizontal plane, the control system includes:

[0028] An inverse resolver processing module, configured to read the electric cylinder length information of each group of electric cylinders through an absolute value encoder and input it into the platform position inverse resolver to obtain the initial position and angle of the floating platform after power-on;

[0029] The acceleration and deceleration filtering module is used to receive a speed control instruction and perform acceleration and deceleration filtering processing to obtain an actual speed control instruction;

[0030] The forward solver processing module is used to input the actual speed control instruction into the platform position forward solver, and combine the initial position and angle of the floating platform to obtain the target extension lengths of each group of electric cylinders;

[0031] The driver control module is used to generate a target length instruction according to the target extension lengths of each group of electric cylinders and send it to the corresponding servo driver to control the servo driver to track the target length instruction in real time;

[0032] The driver loop execution module is used to loop execute the control process of the servo driver until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met.

[0033] An electronic device includes a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes the steps of a control method for a horizontal three-degree-of-freedom platform as described in any one of the above.

[0034] A readable storage medium stores a computer program, and when the computer program is executed by a processor, it is used to implement the steps of a control method for a horizontal three-degree-of-freedom platform as described in any one of the above.

[0035] Compared with the related art, a control method for a horizontal three-degree-of-freedom platform provided by the present invention has the following beneficial effects:

[0036] The present invention can read the electric cylinder length information of each group of electric cylinders through an absolute encoder and input it into the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on; receive a speed control instruction and perform acceleration and deceleration filtering processing to obtain an actual speed control instruction; input the actual speed control instruction into the platform position forward solver, and combine the initial position and angle of the floating platform to obtain the target extension lengths of each group of electric cylinders; generate a target length instruction according to the target extension lengths of each group of electric cylinders and send it to the corresponding servo driver to control the servo driver to track the target length instruction in real time; loop execute the control process of the servo driver until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met, so as to perform high-precision and stable three-degree-of-freedom motion control on the platform.

[0037] The present invention can construct an inverse solver using the gradient descent method. Through continuous iterative optimization, it can accurately calculate the initial position after the platform is powered on. Compared with traditional control methods, it significantly improves the accuracy of initial positioning. The method of the present invention can perform acceleration and deceleration filtering on the speed control command, effectively reducing the impact and vibration during the movement of the platform, and improving the stability and reliability of the platform motion control. The forward solver of the present invention can combine the speed command and the control period to accurately calculate the target extension length of the electric cylinder, and can ensure the high-precision synchronous movement of the four groups of electric cylinders through the cyclic synchronous position mode of the servo electric cylinder, realizing the precise control of the three degrees of freedom of the floating platform in the horizontal plane and meeting the accuracy requirements of the platform movement. Brief Description of the Drawings

[0038] Figure 1 It is a flowchart of a control method for a three-degree-of-freedom platform in the horizontal plane provided by an embodiment of the present invention;

[0039] Figure 2 It is a schematic structural diagram of a three-degree-of-freedom platform in the horizontal plane provided by an embodiment of the present invention;

[0040] Figure 3 It is a system block diagram of a control system for a three-degree-of-freedom platform in the horizontal plane provided by an embodiment of the present invention;

[0041] Figure 4 It is a schematic hardware structure diagram of an electronic device provided by an embodiment of the present invention. Detailed Embodiments

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] As Figure 1 shown, it is a flowchart of a control method for a three-degree-of-freedom platform in the horizontal plane provided by an embodiment of the present invention, Figure 1The execution entity of the method shown can be a software and / or hardware device. The execution entity of this application can include, but is not limited to, at least one of the following: user equipment, network equipment, etc. Among them, the user equipment can include, but is not limited to, a computer, a smart phone, a personal digital assistant (Personal Digital Assistant, abbreviated as: PDA), and the electronic devices mentioned above, etc. The network equipment can include, but is not limited to, a single network server, a server group composed of multiple network servers, or a cloud composed of a large number of computers or network servers based on cloud computing. Among them, cloud computing is a type of distributed computing, which is composed of a group of loosely coupled computers to form a super virtual computer. This embodiment does not limit this. It includes steps S1 to S5, specifically as follows:

[0044] S1. Read the cylinder length information of each group of electric cylinders through an absolute encoder and input it into the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on;

[0045] Among them, the absolute encoder refers to a key sensor installed on the electric cylinder, which is used to accurately measure the telescopic length of the electric cylinder. Different from other types of encoders, the absolute encoder can directly output the digital code corresponding to the cylinder length. Whether the device is powered off or not, it can accurately record the position information of the electric cylinder, ensuring the accuracy and integrity of the data, and providing a reliable basis for the accurate solution of the platform position.

[0046] It should be noted that the platform position inverse solver takes the cylinder length information collected by the absolute encoder as input, and at the same time combines the mechanical structure parameters of the platform, such as the coordinates of each hinge point in different coordinate systems, etc., and uses the gradient descent method. After multiple calculations and optimizations, the initial position and angle information of the platform after power-on are finally obtained.

[0047] S2. Receive the speed control instruction and perform acceleration / deceleration filtering processing to obtain the actual speed control instruction;

[0048] It can be understood that the speed control instruction is issued by the upper-level control system and contains the control requirements for the movement speed and direction of the platform, specifically including the x-axis direction speed of the floating platform in the base coordinate system and the y-axis direction speed of the floating platform in the base coordinate system as well as the rotation speed of the floating platform around the z-axis in the base coordinate system . These instructions clarify the desired motion state of the platform.

[0049] Furthermore, directly executing the original speed control instruction may cause impacts and vibrations during the movement of the platform, thereby affecting the smoothness and accuracy of the movement. Therefore, it is necessary to perform acceleration and deceleration filtering on the speed control instruction. Through a specific filtering algorithm, such as a first-order low-pass filter, etc., the speed control instruction is smoothed, making the platform more stable during startup, stop, and speed change processes, and obtaining the actual speed control instruction 、 、 。

[0050] S3. Input the actual speed control instruction into the platform position forward solver, and combine with the initial position and angle of the floating platform to obtain the target extension lengths of each group of electric cylinders;

[0051] It should be noted that the platform position forward solver takes the actual speed control instruction, control period, and the initial position and angle of the platform as inputs. Through operations such as integrating the speed over time and combining with the kinematic model of the platform, it calculates the target position and angle of the platform at the end of each control period. Furthermore, according to the mechanical structure relationship of the platform, it can calculate the target extension length required for the first group of electric cylinders 、the target extension length required for the second group of electric cylinders 、the target extension length required for the third group of electric cylinders 、the target extension length required for the fourth group of electric cylinders 。

[0052] S4. Generate a target length instruction based on the target extension lengths of each group of electric cylinders and send it to the corresponding servo drive to control the servo drive to track the target length instruction in real time;

[0053] Among them, the servo drive is a key device for controlling the movement of the electric cylinder. It can receive the target length instruction and work in a cyclic synchronous position mode. This mode ensures that each servo drive can work together to adjust the actual extension length of the electric cylinder in real time, making it closely track the target length instruction, so as to realize the synchronous movement of the four groups of electric cylinders and drive the floating platform to move along the expected trajectory and speed.

[0054] S5. Continuously execute the control process of the servo drive until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met.

[0055] In practical applications, the three-degree-of-freedom adjustment termination condition refers to a pre-set standard for judging whether the platform movement is completed. These conditions can be set according to specific application requirements, such as the platform reaching the specified position coordinates, completing the specified movement trajectory, reaching the specified movement time, etc.

[0056] During the process of the servo drive controlling the electric cylinder, the system will continue to loop through the above steps. After each control cycle, the absolute encoder will re-read the length information of the electric cylinder and update the position and angle data of the floating platform. The forward solver will recalculate the target extension length of the electric cylinder based on the new actual speed control command and the updated position and angle information. The servo drive will adjust the movement of the electric cylinder again based on the new target length command.

[0057] This cycle will continue until the three-degree-of-freedom adjustment of the floating platform relative to the base platform meets the preset termination condition, the system stops the cycle, and the entire three-degree-of-freedom adjustment process ends.

[0058] Through the above method, the entire process of platform movement can be accurately controlled, which effectively improves the accuracy and stability of platform movement and is suitable for application scenarios with high requirements for various platform motion control.

[0059] In the specific implementation process, Figure 2 As shown, the base platform and the floating platform are connected via four groups of electric cylinders.

[0060] Among them, the base platform plays a role of stable support in the entire structure. It is the basic part of the entire system and provides installation and positioning reference for other components. It is usually fixed in a stable position to ensure that the entire platform will not be displaced or shaken during operation.

[0061] The floating platform is the part that needs to achieve three-degree-of-freedom motion, namely movement along the x-axis, movement along the y-axis and rotation around the z-axis in the base coordinate system, and precise control of its motion is the key goal of the entire system.

[0062] The four groups of electric cylinders connecting the base platform and the floating platform are the key actuators for realizing the platform movement. Each group of electric cylinders has the characteristics of retractability. By accurately controlling the extension length of the electric cylinder, the position and angle of the floating platform relative to the base platform can be changed. The electric cylinder is equipped with an absolute encoder, which can measure the extension length of the electric cylinder in real time and accurately, and feed back this length information to the control system, providing key data support for the subsequent accurate calculation of the platform position and the realization of motion control.

[0063] During the actual working process, after the control system issues a motion command, based on the current state and target state of the platform, combined with the real-time length information of the electric cylinders, the target extended length that each group of electric cylinders needs to adjust can be calculated. Then, the servo driver is used to control the synchronous operation of the 4 groups of electric cylinders, enabling the electric cylinders to expand and contract according to the target length. For example, when the floating platform needs to move in the x-axis direction, the control system will adjust the length of the corresponding electric cylinders to cause the floating platform to generate a displacement in the x-axis direction; if it is necessary to achieve the rotation of the floating platform around the z-axis, the different expansion and contraction changes of the 4 groups of electric cylinders will be coordinated to generate the torque and displacement required for rotation.

[0064] This method of collaborative work by 4 groups of electric cylinders can achieve complex three-degree-of-freedom motion of the floating platform in the horizontal plane, meeting the requirements of high-precision motion control of the platform.

[0065] Reading the electric cylinder length information of each group of electric cylinders through the absolute encoder and inputting it into the platform position inverse resolver to obtain the initial position and angle of the floating platform after power-on specifically includes:

[0066] After power-on, read the electric cylinder length information of the i-th group of electric cylinders through the absolute encoder ;

[0067] Set the floating platform as u, the base platform as b, and the coordinates of the floating platform in the base coordinate system at the initial moment as , the angle as , obtain the hinge point of the floating platform and the i-th group of electric cylinders, and its coordinates in the floating coordinate system are . After the following coordinate transformation, obtain the coordinates of the hinge point of the floating platform and the i-th group of electric cylinders at the initial moment in the base coordinate system as :

[0068] Obtain the coordinates of the hinge point of the base platform and the i-th group of electric cylinders in the base coordinate system as , construct the loss function as follows:

[0069] Calculate that the derivative of the loss function is , , .

[0070] Select the step size parameter , and update the coordinates of the floating platform at the initial moment in the base coordinate system and the angle , the corresponding coordinate estimation value is obtained and the angle estimation value :

[0071] Repeat the steps of updating the coordinates and angle of the floating platform in the base coordinate system until the loss function is less than the preset loss value, and output the coordinate estimation value of the floating platform in the base coordinate system and the angle estimation value , that is, the initial position and angle of the floating platform after power-on.

[0072] It should be noted that after the platform is powered on and started, the real-time length information of each group of electric cylinders can be obtained first. This is completed by the absolute encoders installed on the electric cylinders, and the absolute encoders can accurately read the actual length of each group of electric cylinders. Taking the i-th group of electric cylinders as an example, the length information of the electric cylinders read by it is the actual working length of the current i-th group of electric cylinders.

[0073] For the convenience of subsequent calculations, the floating platform can be set as u, the base platform can be set as b, and the coordinates and angle of the floating platform in the base coordinate system at the initial moment can be set. Then, it is necessary to obtain the coordinates of the hinge point between the floating platform and the i-th group of electric cylinders in the floating coordinate system, and through the coordinate system conversion method, using the trigonometric function relationship, convert the coordinates of the hinge point between the floating platform and the i-th group of electric cylinders in the floating coordinate system to the base coordinate system, so that the coordinates of this hinge point in the base coordinate system can be obtained.

[0074] Furthermore, the coordinates of the connection point between the base platform and the i-th group of electric cylinders in the floating coordinate system can be obtained. Based on this known information, a loss function for evaluating the calculation accuracy can be constructed. This loss function comprehensively considers the coordinate difference of the hinge point between the floating platform and the i-th group of electric cylinders in the base coordinate system, the coordinates of the hinge point between the base platform and the i-th group of electric cylinders in the floating coordinate system, and the actual length information of the i-th group of electric cylinders.

[0075] In order to continuously optimize the estimated values of the initial position and angle of the floating platform, it is necessary to calculate the change rates of this loss function with respect to the coordinate x, coordinate y, and angle, that is, the derivative of this loss function.

[0076] Immediately afterwards, an appropriate step size parameter can be selected. This parameter determines the change amplitude when adjusting the coordinates and angle of the floating platform in the base coordinate system each time. Using the derivative of the loss function calculated previously and the step size parameter, the coordinates and angle of the floating platform in the base coordinate system at the initial moment can be updated to obtain a new set of coordinate estimation values and angle estimation values.

[0077] This update process needs to be repeated continuously. After each update, the value of the loss function needs to be recalculated and compared with the preset loss value until the value of the loss function is less than the preset loss value. At this time, the coordinate estimation value and the angle estimation value can be output as the initial position and angle of the floating platform in the base coordinate system after power-on, so as to accurately determine the initial state of the floating platform and provide reliable basic data for subsequent precise motion control of the platform.

[0078] Inputting the actual speed control instruction into the platform position forward solver, and combining the initial position and angle of the floating platform to obtain the target extension lengths of each group of electric cylinders specifically includes:

[0079] Receiving the actual speed control instruction 、 、 ;

[0080] Setting the control period as T, and combining the initial position and angle of the floating platform to obtain the target position and angle of the floating platform after the end of one control period as follows:

[0081] Based on the coordinates of the hinge point between the floating platform and the i-th group of electric cylinders in the floating coordinate system, and combining the target position and angle of the floating platform, after the following coordinate transformation, the coordinates of the hinge point between the floating platform and the i-th group of electric cylinders in the base coordinate system after the end of one control period are :

[0082] Combining the coordinates of the hinge point between the base platform and the i-th group of electric cylinders in the base coordinate system, calculating the target extension length of the i-th group of electric cylinders after the end of one control period as follows:

[0083] 。

[0084] It can be understood that first, the processed actual speed control instruction can be received. Then, a control period can be set, which is the time interval for controlling the movement of the platform. Combining the initial position and angle of the floating platform, calculate the target position and angle of the floating platform after the end of one control period.

[0085] Further, combining the coordinates of the hinge point between the floating platform and the i-th group of electric cylinders in the floating coordinate system, as well as the target position and angle of the floating platform calculated previously, through the coordinate system transformation method and using trigonometric function relationships, the coordinates of this hinge point in the floating coordinate system are transformed to the base coordinate system to obtain the new coordinates in the base coordinate system.

[0086] Finally, combining the coordinates of the hinge point between the base platform and the i-th group of electric cylinders in the floating coordinate system, and the new coordinates of the hinge point between the floating platform and the i-th group of electric cylinders in the base coordinate system obtained previously, using the distance formula between two points, the distance between these two points is calculated, that is, after the end of one control cycle, the target extension length of the i-th group of electric cylinders, so that the target extension lengths of each group of electric cylinders under each control cycle can be accurately determined, providing key data support for subsequent controlling the actions of the electric cylinders to achieve precise motion control of the floating platform.

[0087] Based on the target length command, the servo drive adjusts the floating platform in three degrees of freedom according to the cyclic synchronous position mode.

[0088] In practical applications, when the servo drive receives the target length command, it will work according to the cyclic synchronous position mode. The cyclic synchronous position mode is an operation method that ensures the coordinated work of each electric cylinder. In this mode, the servo drive continuously compares the actual extension length of the electric cylinder with the target length command, and adjusts the action of the electric cylinder in real time according to the comparison result, so that the electric cylinder moves in the direction of the target extension length.

[0089] Since there are four groups of electric cylinders connecting the base platform and the floating platform, the precise control of each group of electric cylinders by the servo drive can achieve synchronous movement among the four groups of electric cylinders. For example, when the floating platform needs to move linearly on the horizontal plane, the servo drive will, according to the target length command, make the corresponding electric cylinders extend or shorten a certain length, and ensure the coordinated actions of the four groups of electric cylinders; if it is necessary to rotate the floating platform around a certain axis, the servo drive will perform differential control on the extension lengths of different electric cylinders to generate a resultant force that makes the platform rotate.

[0090] Through continuous cyclic adjustment processes, the servo drive can accurately perform moving and rotating operations on the floating platform in different directions, complete three-degree-of-freedom adjustment on the horizontal plane, and meet various motion requirements of the platform in practical applications.

[0091] Exemplarily, in an industrial automation production line, it is often necessary to perform high-precision positioning and assembly of components. Among them, the precise control of the three-degree-of-freedom platform on the horizontal plane is crucial. The following takes an electronic product assembly production line as an example to illustrate the specific implementation process of this control method.

[0092] On this production line, it is necessary to accurately place tiny electronic chips at designated positions on the circuit board. Therefore, it is required that the platform has high-precision planar positioning and angle adjustment capabilities. After the platform is powered on, the absolute encoder starts to work and reads the real-time length information of four sets of electric cylinders.

[0093] Suppose the length of the first set of electric cylinders is 100 millimeters, the second set is 105 millimeters, the third set is 110 millimeters, and the fourth set is 108 millimeters at this time. Then, these data can be input into the platform position inverse solver.

[0094] In the inverse solver, set the floating platform as u and the base platform as b. The initial estimated coordinates of the floating platform in the base coordinate system are (0, 0), and the angle is 0°. Given that the coordinates of the hinge point between the floating platform and the first set of electric cylinders in the floating coordinate system are (20, 30), through coordinate system transformation operations and combining trigonometric function relationships, the coordinates of this hinge point in the base coordinate system are calculated. Then, obtain the coordinates of the hinge point between the base platform and the first set of electric cylinders in the floating coordinate system, and construct a loss function to evaluate the calculation accuracy. By calculating the derivative of the loss function, select a step size parameter of 0.03, and continuously iterate and update the coordinate and angle estimation values of the floating platform. After multiple calculations, when the loss function is less than the preset value of 0.0001, the initial position of the floating platform is output as (5, -3), and the angle is 5°, laying a data foundation for the subsequent precise control of the platform movement.

[0095] During the movement of the platform, receive the upper-layer speed control instructions, that is, the platform is required to move at a speed of 20 millimeters per second in the x-axis direction, 15 millimeters per second in the y-axis direction, and rotate at a speed of 3° per second around the z-axis. These instructions are processed by acceleration and deceleration filtering to generate actual speed control instructions.

[0096] Furthermore, the actual speed control instructions can be input into the platform position forward solver. Set the control period to 0.05 seconds, and combine the initial position and angle of the floating platform to calculate the target position and angle after the end of one control period. According to the coordinates of the hinge point between the floating platform and the first set of electric cylinders in the floating coordinate system, as well as the target position and angle, through coordinate system transformation again, obtain the new coordinates of this hinge point in the base coordinate system. Then, combine the coordinates of the hinge point between the base platform and the first set of electric cylinders in the floating coordinate system to calculate the target extension length of the first set of electric cylinders, and the same applies to the other three sets of electric cylinders. Suppose the calculated target extension length of the first set of electric cylinders is 102 millimeters, the second set is 106 millimeters, the third set is 112 millimeters, and the fourth set is 110 millimeters.

[0097] Finally, length commands can be generated based on these target extension lengths and sent to the corresponding servo drives. The servo drives track the target length commands in real time according to the cyclic synchronous position mode. During this process, the actual extension length of the electric cylinder is continuously compared with the target length, and the actions of the electric cylinder are adjusted in a timely manner. After multiple control cycles, the platform accurately reaches the target position, and the electronic chip is precisely placed on the circuit board to complete the assembly task.

[0098] Through the above embodiments, it is obtained that the control method of the present invention can achieve high-precision motion control of the three-degree-of-freedom platform on the horizontal plane, meet the strict requirements for platform positioning and angle adjustment in industrial production, and effectively improve production efficiency and product quality.

[0099] As Figure 3 shown, it is a system block diagram of a control system for a three-degree-of-freedom platform on the horizontal plane provided by an embodiment of the present invention. The control system includes:

[0100] An inverse solver processing module, configured to read the electric cylinder length information of each group of electric cylinders through an absolute encoder and input it to the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on;

[0101] An acceleration / deceleration filtering module, configured to receive a speed control command and perform acceleration / deceleration filtering processing to obtain an actual speed control command;

[0102] A forward solver processing module, configured to input the actual speed control command to the platform position forward solver, and combine the initial position and angle of the floating platform to obtain the target extension lengths of each group of electric cylinders;

[0103] A drive control module, configured to generate a target length command according to the target extension lengths of each group of electric cylinders and send it to the corresponding servo drive to control the servo drive to track the target length command in real time;

[0104] A drive loop execution module, configured to loop through the control process of the servo drive until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met.

[0105] Figure 3 The device in the shown embodiment can correspondingly be used to execute the steps in the method embodiment shown in Figure 1 shown. The implementation principle and technical effects are similar, and will not be elaborated here.

[0106] An electronic device includes a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes the steps of a control method for a three-degree-of-freedom platform on the horizontal plane as described in any one of the above.

[0107] AsFigure 4 As shown, it is a schematic diagram of the hardware structure of an electronic device provided by an embodiment of the present invention. The electronic device 40 includes: a processor 41, a memory 42, and a computer program; wherein

[0108] The memory 42 is used to store the computer program, and the memory can also be a flash memory. The computer program is, for example, an application program, a functional module, etc. that implement the above method.

[0109] The processor 41 is used to execute the computer program stored in the memory to implement each step performed by the device in the above method. For specific details, reference can be made to the relevant descriptions in the foregoing method embodiments.

[0110] Optionally, the memory 42 can be either independent or integrated with the processor 41.

[0111] When the memory 42 is a device independent of the processor 41, the device may further include:

[0112] A bus 43 for connecting the memory 42 and the processor 41.

[0113] A readable storage medium stores a computer program, and when the computer program is executed by a processor, it is used to implement the steps of a control method for a three-degree-of-freedom platform on a horizontal plane as described in any one of the above.

[0114] Among them, the readable storage medium can be a computer storage medium or a communication medium. The communication medium includes any medium that facilitates the transmission of a computer program from one place to another. The computer storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer. For example, the readable storage medium is coupled to the processor, so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). In addition, the ASIC can be located in a user device. Of course, the processor and the readable storage medium can also exist as discrete components in a communication device. The readable storage medium can be a read-only memory (ROM), a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0115] The present invention also provides a program product, which includes execution instructions stored in a readable storage medium. At least one processor of the device can read the execution instructions from the readable storage medium, and the execution of the execution instructions by the at least one processor enables the device to implement the methods provided by the above various embodiments.

[0116] In the embodiments of the above device, it should be understood that the processor may be a central processing unit (English: Central Processing Unit, abbreviated as: CPU), or may also be other general-purpose processors, digital signal processors (English: Digital Signal Processor, abbreviated as: DSP), application specific integrated circuits (English: Application Specific Integrated Circuit, abbreviated as: ASIC), etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in combination with the present invention can be directly embodied as being executed and completed by a hardware processor, or executed and completed by a combination of hardware and software modules in the processor.

[0117] Through the introduction of the above embodiments, the control method of the present invention for the three-degree-of-freedom platform on the horizontal plane can read the cylinder length information of each group of electric cylinders through an absolute encoder and input it into the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on; receive the speed control instruction and perform acceleration / deceleration filtering processing to obtain the actual speed control instruction; input the actual speed control instruction into the platform position forward solver, and combine the initial position and angle of the floating platform to obtain the target extension length of each group of electric cylinders; generate a target length instruction according to the target extension length of each group of electric cylinders and send it to the corresponding servo driver to control the servo driver to track the target length instruction in real time; loop through the control process of the servo driver until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met, so as to perform high-precision and stable three-degree-of-freedom motion control on the platform.

[0118] The present invention can use the gradient descent method to construct an inverse solver. Through continuous iteration and optimization, it can accurately calculate the initial position of the platform after power-on. Compared with traditional control methods, the accuracy of initial positioning is significantly improved. The method of the present invention can perform acceleration / deceleration filtering processing on the speed control instruction, effectively reducing the impact and vibration during the movement of the platform, and improving the stability and reliability of the platform motion control. The forward solver of the present invention can accurately calculate the target extension length of the electric cylinder by combining the speed instruction and the control cycle, and can ensure the high-precision synchronous movement of the four groups of electric cylinders through the cyclic synchronous position mode of the servo electric cylinder, realizing the precise control of the three degrees of freedom of the floating platform in the horizontal plane and meeting the accuracy requirements of the platform movement.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for a three-degree-of-freedom platform on a horizontal plane, characterized in that, The control method includes: Reading the cylinder length information of each group of electric cylinders through an absolute encoder and inputting it into the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on; Receiving a speed control instruction and performing acceleration / deceleration filtering processing to obtain an actual speed control instruction; Inputting the actual speed control instruction into the platform position forward solver, and combining the initial position and angle of the floating platform to obtain the target extension lengths of each group of electric cylinders; Generating a target length instruction according to the target extension lengths of each group of electric cylinders and sending it to the corresponding servo driver to control the servo driver to track the target length instruction in real time; Repeatedly executing the control process of the servo driver until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met.

2. The control method of a three-degree-of-freedom platform on a horizontal plane according to claim 1, characterized in that, The base platform and the floating platform are connected by 4 groups of electric cylinders.

3. The control method of a three-degree-of-freedom platform on a horizontal plane according to claim 1, characterized in that, The step of reading the cylinder length information of each group of electric cylinders through an absolute encoder and inputting it into the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on specifically includes: After power-on, the cylinder length information len of the i-th group of electric cylinders is read through the absolute encoder i_real ; Set the floating platform as u, the base platform as b, and the coordinates of the floating platform at the initial moment in the base coordinate system as (x u_b , y u_b ), and the angle as θ u_b . Obtain the coordinates of the hinge point P i_u of the floating platform and the i-th group of electric cylinders in the floating coordinate system as (x i_u , y i_u ). After the following coordinate system transformation, the coordinates of the hinge point P i_u of the floating platform and the i-th group of electric cylinders at the initial moment in the base coordinate system are obtained as (x i_ub , y i_ub ) as follows: Obtain the hinge point Q of the base platform and the i-th group of electric cylinders i_b The coordinates in the base coordinate system are (x i_b , y i_b ), and construct the loss function f(x, y, θ) as follows: The derivative of the calculated loss function f(x, y, θ) is 4. The control method of a three-degree-of-freedom platform on a horizontal plane according to claim 3, characterized in that, Select the step size parameter α, and update the coordinates (x u_b , y u_b ) and the angle θ u_b of the floating platform at the initial moment in the base coordinate system according to the following formula to obtain the corresponding coordinate estimate values (x′ u_b , y′ u_b ) and the angle estimate value θ′ u_b : Repeat the step of updating the coordinates and angle of the floating platform in the base coordinate system until the loss function f(x, y, θ) is less than a preset loss value, and output the coordinate estimate (x′ u_b , y′ u_b ) and the angle estimate θ′ u_b , which are the initial position (x0, y0) and angle θ0 of the floating platform after power-on.

5. A control method for a three-degree-of-freedom platform on a horizontal plane according to claim 1 or 3, characterized in that, The step of inputting the actual speed control instruction into the platform position forward solver, and combining the initial position and angle of the floating platform to obtain the target extension lengths of each group of electric cylinders specifically includes: Receive the actual speed control command v x_ctrl 、v y_ctrl 、ω z_ctrl ; Set the control period as T. Combining the initial position (x0, y0) and the angle θ0 of the floating platform, obtain the target position (x t+1 , y t+1 ) and the angle θ t+1 after the end of one control period as follows: Based on the hinge point P between the floating platform and the i-th group of electric cylinders i_u in the floating coordinate system with coordinates (x i_u , y i_u ), combined with the target position (x t+1 , y t+1 ) and angle θ t+1 of the floating platform, after the following coordinate system transformation, the coordinates of the hinge point P between the floating platform and the i-th group of electric cylinders i_u in the base coordinate system after the end of the control period are (x' i_ub , y' i_ub ) are obtained as follows: The hinge point Q that combines the base platform and the i-th group of electric cylinders i_b The coordinates (x i_b , y i_b ) in the base coordinate system, calculate the target extension length len of the i-th group of electric cylinders after the end of a control cycle i_goal as follows:

6. The control method of a three-degree-of-freedom platform on a horizontal plane according to claim 1, characterized in that, Based on the target length instruction, the servo driver performs three-degree-of-freedom adjustment on the floating platform in a cyclic synchronous position mode.

7. A control system for a three-degree-of-freedom horizontal plane platform, which is applied to the control method of a three-degree-of-freedom horizontal plane platform as described in any one of claims 1-6, characterized in that, The control system includes: An inverse solver processing module for reading the cylinder length information of each group of electric cylinders through an absolute encoder and inputting it into the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on; An acceleration / deceleration filtering module for receiving a speed control instruction and performing acceleration / deceleration filtering processing to obtain an actual speed control instruction; A forward solver processing module for inputting the actual speed control instruction into the platform position forward solver, and combining the initial position and angle of the floating platform to obtain the target extension lengths of each group of electric cylinders; A driver control module for generating a target length instruction according to the target extension lengths of each group of electric cylinders and sending it to the corresponding servo driver to control the servo driver to track the target length instruction in real time; A driver cyclic execution module for repeatedly executing the control process of the servo driver until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met.

8. An electronic device, comprising a memory and a processor, wherein a computer program is stored in the memory, characterized in that, When the processor runs the computer program stored in the memory, the processor executes the steps of a control method for a horizontal three-degree-of-freedom platform according to any one of claims 1-6.

9. A readable storage medium storing a computer program therein, characterized in that, When the computer program is executed by the processor, it is used to implement the steps of a control method for a horizontal three-degree-of-freedom platform according to any one of claims 1-6.

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