Control method of horizontal plane three-degree-of-freedom platform

Abstract

The invention provides a control method for a horizontal plane three-degree-of-freedom platform, and relates to the technical field of automation control, and the method comprises the steps: reading the electric cylinder length information of each group of electric cylinders through an absolute value encoder, and inputting the electric cylinder length information to a platform position reverse solver to obtain the initial position and angle of a powered floating platform; receiving a speed control instruction and performing acceleration and deceleration filtering processing to obtain an actual speed control instruction; the actual speed control instruction is input into a platform position forward solver, and the target extension length of each group of electric cylinders is obtained by combining the initial position and angle of the floating platform; generating a target length instruction according to the target extension length of each group of electric cylinders, sending the target length instruction to a corresponding servo driver, and controlling the servo driver to track the target length instruction in real time; and the control process of the servo driver is circularly executed until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met, so that high-precision and stable three-degree-of-freedom motion control can be performed on the platform.

Description

Technical Field

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

[0002] In modern industrial production, scientific research experiments and other fields, 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, resulting in 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 cannot perform high-precision and stable three-degree-of-freedom motion control on the platform.

[0006] A control method for a three-degree-of-freedom platform on a horizontal plane provided by the present invention, the control method includes: Reading the electric 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 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; 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.

[0007] Preferably, the base platform and the floating platform are connected by 4 groups of electric cylinders.

[0008] Preferably, reading the cylinder length information of each electric cylinder by 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 including: After power-on, reading the cylinder length information of the i-th group of electric cylinders by the absolute encoder ; Setting 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 , obtaining the coordinates of the hinge point of the floating platform and the i-th group of electric cylinders in the floating coordinate system as , after the following coordinate transformation, obtaining 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 : Obtaining the coordinates of the hinge point of the base platform and the i-th group of electric cylinders in the base coordinate system as , constructing a loss function as follows: Calculating the derivative of the loss function as , , .

[0009] Preferably, selecting a step size parameter , updating the coordinates and angle of the floating platform at the initial moment in the base coordinate system according to the following formula to obtain the corresponding coordinate estimate and angle estimate : Repeatedly executing the update steps 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, outputting the coordinate estimate and angle estimate of the floating platform in the base coordinate system, that is, the initial position and angle of the floating platform after power-on.

[0010] 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 length of each electric cylinder, specifically including: Receive the actual speed control instruction , , ; Set the control period as T, and combine with 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: 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, combine with the target position and angle of the floating platform. After the following coordinate system transformation, obtain 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 as: Combine with the coordinates of the hinge point between the base platform and the i-th group of electric cylinders in the base coordinate system to calculate the target extension length of the i-th group of electric cylinders after the end of one control period as follows: .

[0011] 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.

[0012] A control system for a three-degree-of-freedom platform on a horizontal plane, the control system includes: An inverse solver processing module, configured to read the 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; A acceleration and deceleration filtering module, configured to receive a speed control instruction and perform acceleration and deceleration filtering processing to obtain an actual speed control instruction; A forward solver processing module, configured to input the actual speed control instruction to the platform position forward solver, and combine with the initial position and angle of the floating platform to obtain the target extension length of each group of electric cylinders; A driver control module, configured to 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; A drive loop execution module is used to execute the control process of the servo drive in a loop until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met.

[0013] 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 a horizontal plane as described in any one of the above.

[0014] A readable storage medium stores a computer program. 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.

[0015] Compared with the related art, a control method for a three-degree-of-freedom platform on a horizontal plane provided by the present invention has the following beneficial effects: The present invention 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 drive to control the servo drive to track the target length instruction in real time; loop 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, so as to perform high-precision and stable three-degree-of-freedom motion control on the platform.

[0016] 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 the traditional control method, 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 platform movement and improving the stability and reliability of the platform movement 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 period, 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

[0017] Figure 1 It is a flowchart of a control method for a three-degree-of-freedom platform on a horizontal plane provided by an embodiment of the present invention; Figure 2Schematic diagram of the structure of the three-degree-of-freedom platform on the horizontal plane provided by the embodiment of the present invention; Figure 3 System block diagram of a control system of a three-degree-of-freedom platform on the horizontal plane provided by the embodiment of the present invention; Figure 4 Schematic diagram of the hardware structure of an electronic device provided by the embodiment of the present invention. Specific embodiments

[0018] 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 some, but not all, embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] As Figure 1 shown, it is a flowchart of a control method for a three-degree-of-freedom platform on the horizontal plane provided by the embodiment of the present invention. Figure 1 The execution subject of the method shown can be a software and / or hardware device. The execution subject of the present application may include, but is not limited to, at least one of the following: user equipment, network equipment, etc. Among them, the user equipment may include, but is not limited to, a computer, a smart phone, a personal digital assistant (Personal Digital Assistant, abbreviated as: PDA), and the above-mentioned electronic equipment, etc. The network equipment may 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 make any restrictions. It includes steps S1 to S5, which are specifically as follows: 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; Among them, the absolute encoder refers to a key sensor installed on the electric cylinder for accurately measuring the telescopic length of the electric cylinder. Different from other types of encoders, the absolute encoder can directly output a 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 calculation of the platform position.

[0020] 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. Using the gradient descent method, after multiple calculations and optimizations, the initial position and angle information of the platform after power-on are finally obtained.

[0021] S2. Receive the speed control instruction and perform acceleration / deceleration filtering processing to obtain the actual speed control instruction; 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.

[0022] 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 / deceleration filtering processing 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, so that the platform is more stable during startup, stop, and speed change processes, and the actual speed control instruction is obtained 、 、 .

[0023] S3. 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 cylinders; 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 input. Through operations such as integrating the speed over time, combined with the kinematic model of the platform, the target position and angle of the platform at the end of each control period are calculated. Furthermore, according to the mechanical structure relationship of the platform, the target extension length required for the first group of cylinders 、the target extension length required for the second group of cylinders 、the target extension length required for the third group of cylinders 、the target extension length required for the fourth group of cylinders can be calculated.

[0024] S4. Generate a target length instruction according to the target extension lengths of each group of cylinders and send it to the corresponding servo driver to control the servo driver to track the target length instruction in real time; Among them, the servo drive is the 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 so that it can closely track the target length instruction, thereby realizing the synchronous movement of the four groups of electric cylinders and driving the floating platform to move according to the expected trajectory and speed.

[0025] S5, looping and executing the control process of the servo driver until a three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met.

[0026] In practical applications, the three-degree-of-freedom adjustment termination condition refers to the 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 motion trajectory, reaching the specified motion time, etc.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] In the specific implementation process, Figure 2 As shown, the base platform and the floating platform are connected via four groups of electric cylinders.

[0031] 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.

[0032] 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.

[0033] The four sets of electric cylinders connecting the base platform and the floating platform are the key actuating components for realizing the movement of the platform. Each set of electric cylinders has the characteristic of being retractable. By precisely controlling the retractable length of the electric cylinders, the position and angle of the floating platform relative to the base platform can be changed. An absolute encoder is installed on the electric cylinder, which can measure the retractable length of the electric cylinder in real time and accurately, and feedback this length information to the control system, providing key data support for subsequent accurate calculation of the platform position and realization of motion control.

[0034] During the actual working process, after the control system issues a motion command, according to 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 set of electric cylinders needs to adjust can be calculated. Then, the four sets of electric cylinders are controlled to act synchronously through the servo driver, so that the electric cylinders extend and retract 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 cylinder to cause the floating platform to generate a displacement along the x-axis direction; if it is necessary to realize the rotation of the floating platform around the z-axis, the different retractable changes of the four sets of electric cylinders will be coordinated to generate the torque and displacement required for rotation.

[0035] This way of working together by four sets of electric cylinders can realize the complex three-degree-of-freedom movement of the floating platform in the horizontal plane, meeting the requirements of high-precision motion control of the platform.

[0036] The method of reading the 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: After power-on, read the cylinder length information of the i-th group of electric cylinders through the absolute encoder ; 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 coordinate of the hinge point between the floating platform and the i-th group of electric cylinders in the floating coordinate system as . After the following coordinate transformation, obtain the coordinate of the hinge point between the floating platform and the i-th group of electric cylinders at the initial moment in the base coordinate system as : Obtain the coordinate of the hinge point between the base platform and the i-th group of electric cylinders in the base coordinate system as , and construct a loss function as follows: Calculate that the derivative of the loss function is , , .

[0037] Select the step size parameter , and update the coordinates of the floating platform in the base coordinate system at the initial moment according to the following formula and the angle , and obtain the corresponding coordinate estimate value and the angle estimate value : Repeat the update steps of the coordinates and angles 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 value of the floating platform in the base coordinate system and the angle estimate value , that is, the initial position and the angle of the floating platform after power-on

[0038] 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. 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 cylinder length information read by it is the actual working length of the current i-th group of electric cylinders.

[0039] 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 angles of the floating platform in the base coordinate system at the initial moment can be set. Then, the coordinates of the hinge point between the floating platform and the i-th group of electric cylinders in the floating coordinate system need to be obtained, and through the coordinate system transformation method and using the trigonometric function relationship, the coordinates of the hinge point between the floating platform and the i-th group of electric cylinders in the floating coordinate system are transformed into the base coordinate system, so that the coordinates of this hinge point in the base coordinate system can be obtained.

[0040] 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.

[0041] 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, the coordinate y, and the angle, that is, the derivative of this loss function.

[0042] Next, an appropriate step size parameter can be selected. This parameter determines the magnitude of the change each time the coordinates and angles of the floating platform in the base coordinate system are adjusted. Using the derivative of the loss function calculated previously and the step size parameter, the coordinates and angles of the floating platform in the base coordinate system at the initial moment can be updated to obtain a new set of coordinate estimates and angle estimates.

[0043] 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 estimates and angle estimates 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.

[0044] The step of inputting the actual velocity control command 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: Receiving the actual velocity control command 、 、 ; 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: 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 : Combining the coordinates of the hinge point between the base platform and the i-th group of electric cylinders in the base coordinate system , to calculate the target extension length of the i-th group of electric cylinders after the end of one control period as follows: .

[0045] 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, the target position and angle of the floating platform after a control period are calculated.

[0046] Furthermore, 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 into the base coordinate system to obtain the new coordinates in the base coordinate system.

[0047] 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, the target extension length of the i-th group of electric cylinders after a control period. Thus, the target extension lengths of each group of electric cylinders under each control period can be accurately determined, providing key data support for subsequent controlling the actions of the electric cylinders and realizing the precise motion control of the floating platform.

[0048] 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.

[0049] In practical applications, when the servo drive receives the target length instruction, it will work according to the cyclic synchronous position mode. The cyclic synchronous position mode is an operation method to ensure the coordinated work of each electric cylinder. In this mode, the servo driver continuously compares the actual extension length of the electric cylinder with the target length instruction and adjusts the action of the electric cylinder in real time according to the comparison result, making the electric cylinder move in the direction of the target extension length.

[0050] 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 driver can achieve the synchronous movement between the four groups of electric cylinders. For example, when the floating platform needs to move linearly on the horizontal plane, the servo driver will, according to the target length instruction, 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 realize the rotation of the floating platform around a certain axis, the servo driver will perform differential control on the extension lengths of different electric cylinders to generate the resultant force for the platform to rotate.

[0051] Through the continuous cyclic adjustment process, the servo driver can accurately perform moving and rotating operations on the floating platform in different directions, complete the three-degree-of-freedom adjustment on the horizontal plane, and meet various motion requirements of the platform in practical applications.

[0052] 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 a three-degree-of-freedom platform on a horizontal plane is crucial. Taking an electronic product assembly production line as an example, the specific implementation process of this control method is described below.

[0053] 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 groups of electric cylinders.

[0054] Suppose the length of the first group of electric cylinders is 100 millimeters, the second group is 105 millimeters, the third group is 110 millimeters, and the fourth group is 108 millimeters at this time. Then, these data can be input into the platform position inverse solver.

[0055] In the inverse solver, the floating platform is set as u and the base platform is set 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 group of electric cylinders in the floating coordinate system are (20, 30), through coordinate transformation operations and combined with trigonometric function relationships, the coordinates of this hinge point in the base coordinate system are calculated. Then, the coordinates of the hinge point between the base platform and the first group of electric cylinders in the floating coordinate system are obtained, and a loss function is constructed to evaluate the calculation accuracy. By calculating the derivative of the loss function and selecting a step size parameter of 0.03, the coordinate and angle estimation values of the floating platform are continuously iteratively updated. 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.

[0056] During the movement of the platform, upper-layer speed control instructions are received, that is, it is required that the platform moves at a speed of 20 millimeters per second in the x-axis direction, 15 millimeters per second in the y-axis direction, and rotates at a speed of 3° per second around the z-axis. These instructions are processed by acceleration / deceleration filtering to generate actual speed control instructions.

[0057] Further, the actual speed control command can be input into the platform position forward resolver. Set the control period to 0.05 seconds. 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 group of electric cylinders in the floating coordinate system, as well as the target position and angle, through coordinate 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 group of electric cylinders in the floating coordinate system to calculate the target extension length of the first group of electric cylinders. The same applies to the other three groups of electric cylinders. Suppose the calculated target extension lengths of the first group of electric cylinders are 102 mm, the second group is 106 mm, the third group is 112 mm, and the fourth group is 110 mm.

[0058] 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, continuously compare the actual extension length of the electric cylinders with the target length and adjust the actions of the electric cylinders in a timely manner. After multiple control period cycles, the platform accurately reaches the target position, and the electronic chip is precisely placed on the circuit board to complete the assembly task.

[0059] Through the above embodiments, it is concluded 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.

[0060] 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: An inverse resolver processing module, configured to read the cylinder length information of each group of electric cylinders through an absolute encoder and input it into the platform position inverse resolver to obtain the initial position and angle of the floating platform after power-on; An acceleration / deceleration filtering module, configured to receive the speed control command and perform acceleration / deceleration filtering processing to obtain the actual speed control command; A forward resolver processing module, configured to input the actual speed control command into the platform position forward resolver, and combine the initial position and angle of the floating platform to obtain the target extension lengths of each group of electric cylinders; A drive control module, configured to generate target length commands based on the target extension lengths of each group of electric cylinders and send them to the corresponding servo drives to control the servo drives to track the target length commands in real time; A drive loop execution module, configured to loop and execute the control process of the servo drives until the three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met.

[0061] Figure 3 The device of the illustrated embodiment can correspondingly be used to execute Figure 1 the steps in the illustrated method embodiment, and their implementation principles and technical effects are similar, which will not be elaborated here.

[0062] 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 the control method of a three-degree-of-freedom platform on a horizontal plane as described in any one of the above.

[0063] As Figure 4 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; where The memory 42 is used to store the computer program, and this 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.

[0064] The processor 41 is used to execute the computer program stored in the memory to implement each step executed by the device in the above method. Specifically, reference can be made to the relevant descriptions in the foregoing method embodiments.

[0065] Optionally, the memory 42 can be either independent or integrated with the processor 41.

[0066] When the memory 42 is a device independent of the processor 41, the device may further include: A bus 43 for connecting the memory 42 and the processor 41.

[0067] 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 the control method of a three-degree-of-freedom platform on a horizontal plane as described in any one of the above.

[0068] 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 accessible by a general 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.

[0069] 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 at least one processor enables the device to implement the methods provided by the above various embodiments.

[0070] In the above embodiment of the device, it should be understood that the processor can be a central processing unit (CPU), and can also be other general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), etc. The general purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in combination with the present invention can be directly embodied as being completed by the execution of a hardware processor, or by a combination of hardware and software modules in the processor.

[0071] Through the introduction of the above embodiments, the control method of the three-degree-of-freedom platform on the horizontal plane of the present invention can read the cylinder length information of each group of electric cylinders through an absolute encoder and input it into the inverse resolver of the platform position, so as to obtain the initial position and angle of the floating platform after power-on; receive the speed control instruction and perform acceleration and deceleration filtering processing to obtain the actual speed control instruction; input the actual speed control instruction into the forward resolver of the platform position, 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 that the three-degree-of-freedom motion control of the platform can be carried out with high precision and stability.

[0072] The present invention can use the gradient descent method to construct an inverse resolver. Through continuous iterative optimization, it can accurately calculate the initial position of the platform after power-on. Compared with the traditional control method, it significantly improves the accuracy of initial positioning. The method of the present invention can perform acceleration and deceleration filtering processing on the speed control instruction, effectively reducing the impact and vibration during the platform movement and improving the stability and reliability of the platform movement control. The forward resolver of the present invention can combine the speed instruction 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.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; 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 make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for a horizontal three-degree-of-freedom platform, characterized in that: The control method comprises: The electric cylinder length information of each group of electric cylinders is read through the absolute value encoder and input into the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on; Receive speed control instructions and perform acceleration and deceleration filtering to obtain actual speed control instructions; The actual speed control command is input into the platform position forward solver, and the target extension length of each group of electric cylinders is obtained in combination with the initial position and angle of the floating platform; 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, and control the servo driver to track the target length instruction in real time; The control process of the servo drive is executed cyclically until a three-degree-of-freedom adjustment termination condition of the floating platform relative to the base platform is met.

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

3. The control method of a horizontal three-degree-of-freedom platform according to claim 1, characterized in that: The absolute value encoder is used to read the electric cylinder length information of each group of electric cylinders and input it into the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on, which specifically includes: After power-on, the absolute value encoder is used to read the cylinder length information of the i-th group of cylinders. ; Assume that the floating platform is u, the base platform is b, and the coordinates of the floating platform in the base coordinate system at the initial moment are , angle is , obtain the hinge point between the floating platform and the i-th group of electric cylinders The coordinates in the floating coordinate system are , after the following coordinate system transformation, the hinge point between the floating platform and the i-th group of electric cylinders at the initial moment is obtained: The coordinates in the base coordinate system are : Get the hinge point between the base platform and the i-th group of electric cylinders The coordinates in the base coordinate system are , construct the loss function as follows: Calculate the loss function The derivative of , , .

4. The control method of a horizontal plane three-degree-of-freedom platform according to claim 3, characterized in that: Select the step size parameter , update the coordinates of the floating platform at the initial moment in the base coordinate system according to the following formula: and angle , and obtain the corresponding coordinate estimates and angle estimates : Repeat the steps of updating the coordinates and angles of the floating platform in the base coordinate system until the loss function is less than a preset loss value, outputting the estimated coordinate value of the floating platform in the base coordinate system and angle estimates , i.e. the initial position of the floating platform after power-on and angle .

5. The control method of a horizontal three-degree-of-freedom platform according to claim 1 or 3, characterized in that: The actual speed control command is input into the platform position forward solver, and the target extension length of each group of electric cylinders is obtained in combination with the initial position and angle of the floating platform, specifically including: Receive the actual speed control instruction , , ; Set the control period to T, combined with the initial position of the floating platform and angle , and obtain the target position of the floating platform after the control cycle ends. and angle as follows: Based on the hinge point between the floating platform and the i-th group of electric cylinders The coordinates in the floating coordinate system , combined with the target position of the floating platform and angle After the following coordinate system transformation, the hinge point between the floating platform and the i-th group of electric cylinders is obtained after the control cycle ends. The coordinates in the base coordinate system are : Combining the base platform with the hinge point of the i-th group of electric cylinders The coordinates in the base coordinate system , calculate the target extension length of the i-th group of electric cylinders after the control cycle ends as follows: 。 6. The control method of a horizontal three-degree-of-freedom platform according to claim 1, characterized in that: Based on the target length instruction, the servo driver adjusts the floating platform in three degrees of freedom according to a cyclic synchronous position mode.

7. A control system for a horizontal plane three-degree-of-freedom platform, applied to a control method for a horizontal plane three-degree-of-freedom platform as claimed in any one of claims 1 to 6, characterized in that: The control system comprises: The inverse solver processing module is used to read the electric cylinder length information of each group of electric cylinders through the absolute value encoder and input it into the platform position inverse solver to obtain the initial position and angle of the floating platform after power-on; The acceleration and deceleration filtering module is used to receive the speed control instruction and perform acceleration and deceleration filtering to obtain the actual speed control instruction; A forward solver processing module is used to input the actual speed control instruction into the platform position forward solver, and obtain the target extension length of each group of electric cylinders in combination with the initial position and angle of the floating platform; A driver control module, used for generating a target length instruction according to the target extension length of each group of electric cylinders and sending the target length instruction to the corresponding servo driver, and controlling the servo driver to track the target length instruction in real time; The drive loop execution module is used to loop 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.

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

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

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