Sensorless cable drive mechanism position compensation method

Abstract

The application discloses a sensorless flexible cable driving mechanism position compensation method, a test device designed for flexible cable driving mechanism position compensation, and a method for simulating various flight conditions by loading different angles and different directions of load forces on a telescopic wing simulation piece; the flexible cable driving mechanism is installed on the test device to carry out ground tests, linear relationships between load forces and flexible cable deformation variables are obtained, linear relationships between motor q-axis current values, motor rotating speeds, rotating variable values and flexible cable deformation variables are obtained, and a characteristic relationship matrix is established; after the telescopic wing aircraft takes off, a position compensation algorithm is established according to stroke displacement instructions and the characteristic relationship matrix, the motion acceleration of the flexible cable driving mechanism at each moment is obtained, the flexible cable driving mechanism is controlled to move according to the acceleration based on a load spectrum curve, and real-time position compensation is realized.

Description

Technical Field

[0001] This invention relates to a sensorless position compensation method for a flexible cable drive mechanism, belonging to the field of flexible drive mechanism control technology. Background Technology

[0002] Existing positioning and position compensation methods for flexible drive mechanisms can be broadly classified into three categories: acquiring system position information based on position / angle sensors on the mechanism; designing model prediction algorithms through a large amount of experimental data; and introducing feedforward links to modify the system controller.

[0003] Installing displacement or angle sensors on flexible actuators is a relatively intuitive method and allows for real-time observation of the system's position and attitude control. This method is commonly used in multi-degree-of-freedom flexible actuator robot systems. However, this method places high demands on the spatial structure of the actuator and is not entirely suitable for cable-driven actuators designed for intelligent deformable aircraft with flat, narrow, and variable wing configurations, as sensor installation is challenging. Furthermore, designing model prediction algorithms requires acquiring a large amount of experimental data to train the network model, making it unsuitable for cable-driven actuators in deformable aircraft that are highly susceptible to disturbances from external environmental factors.

[0004] Considering that traditional PID control does not perform well under flexible / elastic loads, many improvement methods have emerged, such as introducing feedforward control or passive filtering. However, due to the limitations of the PID control principle itself, it does not perform well when dealing with more complex transmission mechanisms such as wire ropes or multi-mass transmission systems. Furthermore, the fuzzy control that emerged later cannot fully utilize the system feedback data and has poor stability. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a sensorless flexible cable drive mechanism position compensation method. Through the position control compensation design without feedback links, the control accuracy target of the flexible drive mechanism is achieved.

[0006] The technical solution of this invention is:

[0007] A sensorless position compensation method for a flexible cable drive mechanism includes:

[0008] The test device designed for position compensation of the flexible cable drive mechanism simulates various flight conditions by applying load forces at different angles and in different directions to the telescopic wing simulator.

[0009] The flexible cable drive mechanism was installed on the test device, and a ground test was carried out: the test device applied load forces of different values ​​at different horizontal angles to the telescopic wing simulator, and at the same time, the motor of the flexible cable drive mechanism output the same magnitude and opposite direction of the drive force. The corresponding deformation of the flexible cable in the flexible cable mechanism was recorded, and the linear relationship between the load force and the deformation of the flexible cable was obtained.

[0010] The test apparatus applies load force according to the set load spectrum curve, and the flexible cable drive mechanism moves according to the set stroke displacement command. The q-axis current value, motor speed, resolver value, and actual displacement are recorded at each moment during the movement to obtain the q-axis current i. q The linear relationships between the load force, motor speed, resolver value, and load force are obtained based on the linear relationship between load force and cable deformation. q The linear relationships between the values ​​of the motor speed, the resolver value, and the flexible cable deformation are established, and a characteristic relationship matrix is ​​established based on the linear relationships.

[0011] After the telescopic wing aircraft takes off, a position compensation algorithm is established based on the travel displacement command and characteristic relationship matrix to obtain the motion acceleration of the flexible cable drive mechanism at each moment. The flexible cable drive mechanism is then controlled to move according to the acceleration based on the load spectrum curve to achieve real-time position compensation.

[0012] Preferably, the test apparatus includes a test bench, a first slide rail, a second slide rail, a first slider, a second slider, a telescopic wing simulator, a horizontal loading channel, a vertical loading channel, a telescopic locking device, a force sensor, a displacement sensor, and a tilt sensor.

[0013] The first slide rail is fixed to the top of the platform's vertical surface, and the second slide rail is fixed to the bottom of the platform. Both slide rails are installed horizontally. The first slider and the second slider are located on the first slide rail and the second slide rail, respectively.

[0014] The telescopic wing simulator is fixed on the first slider to simulate the deflection deformation of the wing surface under aerodynamic forces.

[0015] The test bench is an L-shaped structure. The motor end of the cable drive mechanism under test is fixed on the vertical surface of the test bench. The slider of the cable drive mechanism under test is fixedly connected to the telescopic wing simulation component. The slider moves with the deformable wing.

[0016] The horizontal loading channel is equipped with a loading electric cylinder, which is fixed to the upper part of the platform. The loading direction is parallel to the movement direction of the telescopic wing.

[0017] The vertical loading channel is equipped with a vertical loading electric cylinder and a follow-up drive cylinder. The vertical loading electric cylinder is mounted on the second slider via a rear lug, and the follow-up drive cylinder is mounted at the bottom of the platform facade. The output shaft of the follow-up drive cylinder is connected to the bottom of the vertical loading electric cylinder. The follow-up drive cylinder pushes the vertical loading cylinder to move synchronously with the telescopic wing simulator, so that the loading force output by the vertical loading cylinder to the telescopic wing remains perpendicular to the wing surface.

[0018] The telescopic locking device is fixedly connected to the telescopic wing simulator to limit the extension angle of the telescopic wing simulator;

[0019] Each of the above electric cylinders is equipped with a displacement sensor and a load sensor to collect the displacement of the telescopic wing simulator in the corresponding direction and the load force output by the electric cylinder; the angle sensor is installed on the first slide rail.

[0020] Preferably, the test device applies load forces of different values ​​at different horizontal angles to the telescopic wing simulator. Specifically, this includes: applying a load force at a horizontal angle, the load force being 10% of the maximum load force borne by the simulator, and recording the corresponding deformation of the flexible cable in the flexible cable mechanism; unloading and then applying a load force of the same magnitude in the opposite direction, and recording the corresponding deformation of the flexible cable in the flexible cable mechanism; repeating the above operation by increasing the load force by 5% each time until the maximum load force borne by the simulator is reached.

[0021] Preferably, based on the linear relationship between the load force and the flexible cable deformation, the linear relationships between the motor q-axis current value, motor speed, resolver value and the flexible cable deformation are obtained, wherein the flexible cable deformation is obtained by subtracting the actual displacement from the specified displacement value of the stroke displacement command.

[0022] Preferably, two parameters, the slope of the q-axis current change and temperature, are added to obtain the linear relationship between the slope of the q-axis current change and temperature and the load force. Based on the linear relationship between the load force and the flexible cable deformation, the linear relationships between the q-axis current value, motor speed, resolver value, slope of the q-axis current change, temperature and flexible cable deformation are obtained. A characteristic relationship matrix is ​​established based on the linear relationship.

[0023] Preferably, based on the stroke displacement command and the characteristic relationship matrix, and using a position compensation algorithm, the motion acceleration of the flexible cable drive mechanism at each moment is obtained. The position compensation algorithm includes:

[0024] Based on the measured q-axis current, motor speed, and resolver value at the current moment, the corresponding flexible cable deformation value is obtained by querying the characteristic relationship matrix;

[0025] Add the index displacement value in the current stroke displacement command to the cable deformation value to obtain the actual displacement amount required to reach the index position. Based on the displacement equation of the stroke displacement command, obtain the acceleration value required for the cable drive mechanism to move at the current moment.

[0026] Preferably, based on the load force applied by several sets of test devices and the corresponding deformation of the flexible cable, the linear relationship between the load force and the deformation of the flexible cable is calculated by the least squares method.

[0027] Preferably, position compensation simulation is performed based on the retractable wing aircraft simulation model: input displacement compensation algorithm, travel displacement command, and motor q-axis current value, motor speed, and resolver value at each time moment to obtain the actual position of the aircraft at each time moment after compensation, and compare it with the command position. If the error value is less than 3.0mm, the displacement compensation algorithm is considered to be effective.

[0028] Preferably, if the displacement compensation algorithm is effective, the displacement compensation algorithm is burned into the controller of the flexible cable drive mechanism and verified on the ground to further determine the accuracy of the position compensation method of the flexible cable drive mechanism.

[0029] The advantages of this invention compared to the prior art are:

[0030] This invention designs a high-precision position control algorithm. This algorithm has no position information feedback link. It calculates the key changes in the control timing by establishing the system error characteristic relationship. Therefore, it can judge the load changes of the mechanism working condition level according to the system input parameters, thereby obtaining the deformation of the system transmission mechanism and compensating for the end position of the mechanism. It can achieve that the system position control error does not exceed the maximum stroke of 440±3.0mm under variable load conditions. Attached Figure Description

[0031] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0032] Figure 1 This is a schematic diagram of the comprehensive working condition test device according to an embodiment of the present invention;

[0033] Figure 2 This is a curve showing the motion stroke load spectrum of the flexible cable drive mechanism according to an embodiment of the present invention.

[0034] Figure 3 This is a flowchart of a method according to an embodiment of the present invention;

[0035] Figure 4 This is a position command curve diagram of the simulation model in an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the input and output error of the position compensation system model according to an embodiment of the present invention;

[0037] Figure 6 This is a diagram showing the position deviation of the actuator's moving end point measured by the test apparatus in an embodiment of the present invention.

[0038] Figure 7 This is a diagram showing the verification results of the position deviation of the actual actuator in an embodiment of the present invention. Detailed Implementation

[0039] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0040] This invention proposes a sensorless position compensation method for a flexible cable drive mechanism. The flexible cable drive mechanism includes a flexible cable, a slider, a motor, a driving wheel, and a driven wheel. The motor drives the driving wheel to rotate, and the driving wheel moves the flexible cable wound between the driving wheel and the driven wheel. The slider located on the flexible cable moves accordingly. Figure 3 As shown, it specifically includes:

[0041] 1) Construct a test device that can simulate the comprehensive working conditions of a cable-driven mechanism.

[0042] Test apparatus such as Figure 1 As shown, the test apparatus includes a test stand 1, a first slide rail 2, a second slide rail 3, a first slider 4, a second slider 5, a telescopic wing simulator 6, a horizontal loading channel 7, a vertical loading channel 8, and a telescopic locking device 9.

[0043] The first slide rail 2 and the second slide rail 3 are fixedly connected to the test stand 1 and are both installed horizontally. The first slider 4 and the second slider 5 are located on the first slide rail 2 and the second slide rail 3, respectively. The telescopic wing simulator 6 is fixed on the first slider 4. The motor end of the cable drive mechanism to be tested is fixed on the vertical surface of the test stand 1, and the slider of the cable drive mechanism is fixedly connected to the telescopic wing simulator 6. The horizontal loading channel 7 is equipped with a loading electric cylinder, which is fixed on the upper part of the vertical surface of the test stand 1, and the loading direction is parallel to the movement direction of the telescopic wing. The vertical loading channel 8 is equipped with a vertical loading electric cylinder and a follow-up drive cylinder. The vertical loading electric cylinder is installed on the second slider 5 through a rear lug, and the follow-up drive cylinder is installed at the bottom end of the vertical surface of the test stand 1. The output shaft of the follow-up drive cylinder is connected to the bottom end of the vertical loading electric cylinder. The telescopic locking device 9 is fixedly connected to the telescopic wing simulator 6. Displacement sensors and load sensors are installed on each of the above electric cylinders to collect the displacement of the telescopic wing simulator 6 in the corresponding direction and the load force output by the electric cylinder. An angle sensor is installed on the first slide rail 2.

[0044] The test apparatus can apply active or passive loads to the flexible cable drive mechanism through horizontal and vertical loading channels, and can simulate various complex flight conditions by changing the mechanism's installation angle and direction, as well as the parameters of the preload device. Simultaneously, the integrated test apparatus is equipped with various physical quantity sensors to collect parameters of the flexible cable drive mechanism's control system and apply them to system error characteristic relationship analysis and calibration verification tests.

[0045] 2) Design of a method for measuring the deformation of flexible cables in a flexible cable mechanism

[0046] The flexible cable drive mechanism actuator was fixed on the test bench and mechanically calibrated. The test bench was used to change the load force, increasing it by 1 kN from 2 kN to 21 kN. The position data of the grating measurement on the test bench after loading was read, and the deformation Δx of the flexible cable drive mechanism under different load conditions (without load device installed) was recorded. n The test bench was unloaded and the orientation of the horizontal load force was changed, and the above steps were repeated. Finally, the linear relationship curve F between the load and the deformation of the flexible cable drive mechanism was calculated using the least squares method. n -Δx n .

[0047] 3) Establish the relationship between systematic error characteristics

[0048] The flexible cable drive mechanism does not use tension / compression sensors or position sensors. Before performing position accuracy compensation on the mechanism, the system load needs to be divided into four segments according to the set stroke displacement command. The load spectrum of the flexible cable drive mechanism after division is as follows: Figure 2As shown, the load force corresponding to the first segment of the stroke (160mm-0mm) is 15.7kN-12.7kN; the load force corresponding to the second segment of the stroke (0mm-440mm) is 205kN-9.7kN; the load force corresponding to the third segment of the stroke (440mm-0mm) is 20.7kN-12.7kN; and the load force corresponding to the fourth segment of the stroke (0mm-160mm) is 205kN-5.1kN. Then, a characteristic relationship matrix is ​​established between the system input parameters and the motion position error of the flexible cable drive mechanism, specifically including:

[0049] The test apparatus was used to simulate various working conditions, according to different directions and different strokes. Figure 2 The load spectrum curve is used to apply segmented loading to the actuator of the flexible cable drive mechanism. The test instrument's industrial control computer, which is paired with the testing device, sends stroke displacement commands to the flexible cable drive mechanism, records the position data of the slider measured by the grating on the test bench at the beginning and end of each stroke segment, and saves the system input parameter data in the test instrument's industrial control computer. Based on the linear relationship between load force and flexible cable deformation... Analysis revealed that in the flexible cable electromechanical actuator system, besides the motor q-axis current, other input parameters that characterize changes in operating conditions and load include the slope of change, temperature, motor speed, and resolver variations. The motor q-axis current i was obtained. q Linear relationships between value, motor speed, resolver value and cable deformation.

[0050] The actual stroke of the slider on the actuator is calculated by subtracting the grating position measurement data from the start and end points of each stroke. Then, the actual displacement error ΔS for each stroke is calculated by subtracting this value from the commanded stroke. n And obtain the average parameter value corresponding to the last 5mm displacement in each stroke segment, and establish a linear relationship with the linear relationship curve F. n -Δx n Perform proportional calculations to obtain a matrix table of characteristic relationships between system input parameters and displacement errors, with a table dimension greater than 2.

[0051] 4) Calculate the control timing variation.

[0052] Different displacement command control timing sequences are set according to the motion direction and stroke of the flexible cable drive mechanism. The timing equations are as follows:

[0053]

[0054]

[0055] S1 and S3 are positive strokes with displacements of 160mm-0mm and 440mm-0mm respectively. S2 and S4 are negative strokes with displacements of 0mm-440mm and 0mm-160mm respectively. When the displacement is 160mm, the timing requirement is less than 0.9s. When the displacement is 440mm, the timing requirement is less than 1.9s.

[0056] In actual flight, the controller must control the motion stroke by controlling the acceleration of the cable-driven mechanism. Therefore, the system displacement error ΔS corresponding to the system input parameters when the actuator reaches the end of its stroke is obtained through the characteristic relationship matrix in step 3). n Substituting these values ​​into the displacement-time equation, the acceleration 'a' corresponding to different command segments in the travel command is calculated. i value:

[0057]

[0058]

[0059]

[0060]

[0061] 5) Verify the accuracy of the position compensation method based on simulation.

[0062] Establish a Simulink system simulation model, embed the characteristic relationship matrix table from step 3) into the Fcn position compensation module of the model, change the input position command and observe the system output, such as... Figure 4 As shown, the calculated error between the position and the command should be less than 3.0 mm, and the actual error is less than 1.15 mm. Figure 5 As shown; then the industrial control computer will burn the modified displacement control timing equation in 4) into the system control drive module.

[0063] The reliability and feasibility of this method were verified by conducting offline model simulation and building a test device for a flexible cable drive mechanism that can simulate comprehensive working conditions. The control drive module was reconnected to the test device including the flexible cable drive mechanism, and step 3) was repeated. The compensated end-effector positioning accuracy error was calculated. The conclusion was that the end-effector positioning error for each segment of variable load stroke was less than 3.0 mm. Figure 6 , Figure 7 As shown, it can meet the target requirements for end motion accuracy of the flexible cable drive mechanism, and the system position control error does not exceed the maximum stroke of 440±3.0mm under variable load conditions.

[0064] The embodiments described above are merely preferred embodiments of the present invention. Ordinary variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A sensorless flexible cable drive mechanism position compensation method, characterized in that, include: The test device designed for position compensation of the flexible cable drive mechanism simulates various flight conditions by applying load forces at different angles and in different directions to the telescopic wing simulator. The flexible cable drive mechanism was installed on the test device, and a ground test was carried out: the test device applied load forces of different values ​​at different horizontal angles to the telescopic wing simulator, and at the same time, the motor of the flexible cable drive mechanism output the same magnitude and opposite direction of the drive force. The corresponding deformation of the flexible cable in the flexible cable mechanism was recorded, and the linear relationship between the load force and the deformation of the flexible cable was obtained. The test apparatus applies load force according to the set load spectrum curve, and the flexible cable drive mechanism moves according to the set stroke displacement command. The q-axis current value, motor speed, resolver value, and actual displacement are recorded at each moment during the movement to obtain the q-axis current i. q The linear relationships between the load force, motor speed, resolver value, and load force are obtained based on the linear relationship between load force and cable deformation. q The linear relationships between the values ​​of the motor speed, the resolver value, and the flexible cable deformation are established, and a characteristic relationship matrix is ​​established based on the linear relationships. After the telescopic wing aircraft takes off, a position compensation algorithm is established based on the travel displacement command and characteristic relationship matrix to obtain the motion acceleration of the flexible cable drive mechanism at each moment. The flexible cable drive mechanism is then controlled to move according to the acceleration based on the load spectrum curve to achieve real-time position compensation.

2. The position compensation method for a sensorless flexible cable drive mechanism according to claim 1, characterized in that, The test apparatus includes a test bench, a first slide rail, a second slide rail, a first slider, a second slider, a telescopic wing simulator, a horizontal loading channel, a vertical loading channel, a telescopic locking device, a force sensor, a displacement sensor, and a tilt sensor. The first slide rail is fixedly connected to the top of the platform's vertical surface, and the second slide rail is fixedly connected to the bottom surface of the platform. Both slide rails are installed horizontally. The first slider and the second slider are located on the first slide rail and the second slide rail, respectively. The telescopic wing simulator is fixed on the first slider to simulate the deflection deformation of the wing surface under aerodynamic forces. The test bench is an L-shaped structure. The motor end of the cable drive mechanism under test is fixed on the vertical surface of the test bench. The slider of the cable drive mechanism under test is fixedly connected to the telescopic wing simulation component. The slider moves with the deformable wing. The horizontal loading channel is equipped with a loading electric cylinder, which is fixed to the upper part of the platform. The loading direction is parallel to the movement direction of the telescopic wing. The vertical loading channel is equipped with a vertical loading electric cylinder and a follow-up drive cylinder. The vertical loading electric cylinder is mounted on the second slider via a rear lug, and the follow-up drive cylinder is mounted at the bottom of the platform facade. The output shaft of the follow-up drive cylinder is connected to the bottom of the vertical loading electric cylinder. The follow-up drive cylinder pushes the vertical loading cylinder to move synchronously with the telescopic wing simulator, so that the loading force output by the vertical loading cylinder to the telescopic wing remains perpendicular to the wing surface. The telescopic locking device is fixedly connected to the telescopic wing simulator to limit the extension angle of the telescopic wing simulator; Each of the above electric cylinders is equipped with a displacement sensor and a load sensor to collect the displacement of the telescopic wing simulator in the corresponding direction and the load force output by the electric cylinder; the angle sensor is installed on the first slide rail.

3. The position compensation method for a sensorless flexible cable drive mechanism according to claim 1, characterized in that, The test apparatus applies load forces of different values ​​at different horizontal angles to the telescopic wing simulator. Specifically, this includes: applying a load force at a horizontal angle, with the load force value being 10% of the maximum load force that the simulator can withstand, and recording the corresponding deformation of the flexible cable in the flexible cable mechanism; unloading and then applying a load force of the same magnitude in the opposite direction, and recording the corresponding deformation of the flexible cable in the flexible cable mechanism; repeating the above operation by increasing the load force by 5% each time until the maximum load force that the simulator can withstand is reached.

4. The position compensation method for a sensorless flexible cable drive mechanism according to claim 1, characterized in that, Based on the linear relationship between load force and flexible cable deformation, the linear relationships between the motor q-axis current, motor speed, resolver value and flexible cable deformation are obtained. The flexible cable deformation is obtained by subtracting the actual displacement from the specified displacement of the stroke displacement command.

5. The position compensation method for a sensorless flexible cable drive mechanism according to claim 4, characterized in that, By adding two parameters, the slope of the q-axis current change and temperature, the linear relationships between the slope of the q-axis current change and temperature and the load force are obtained. Based on the linear relationship between the load force and the flexible cable deformation, the linear relationships between the q-axis current value, motor speed, resolver value, slope of the q-axis current change, and temperature and the flexible cable deformation are obtained. Based on the linear relationships, a characteristic relationship matrix is ​​established.

6. The position compensation method for a sensorless flexible cable drive mechanism according to claim 1, characterized in that, Based on the stroke displacement command and characteristic relationship matrix, and using a position compensation algorithm, the motion acceleration of the flexible cable drive mechanism at each moment is obtained. The position compensation algorithm includes: Based on the measured q-axis current, motor speed, and resolver value at the current moment, the corresponding flexible cable deformation value is obtained by querying the characteristic relationship matrix; Add the index displacement value in the current stroke displacement command to the cable deformation value to obtain the actual displacement amount required to reach the index position. Based on the displacement equation of the stroke displacement command, obtain the acceleration value required for the cable drive mechanism to move at the current moment.

7. The position compensation method for a sensorless flexible cable drive mechanism according to claim 1, characterized in that, Based on the load force and corresponding deformation of the flexible cable obtained from several sets of test devices, the linear relationship between the load force and the deformation of the flexible cable is calculated by the least squares method.

8. The position compensation method for a sensorless flexible cable drive mechanism according to claim 1, characterized in that, Based on the simulation model of the telescopic wing aircraft, position compensation simulation is performed: input displacement compensation algorithm, travel displacement command, and motor q-axis current value, motor speed, and resolver value at each time moment to obtain the actual position of the aircraft at each time moment after compensation, and compare it with the command position. If the error value is less than 3.0mm, the displacement compensation algorithm is considered to be effective.

9. The position compensation method for a sensorless flexible cable drive mechanism according to claim 8, characterized in that, If the displacement compensation algorithm is effective, it will be programmed into the controller of the flexible cable drive mechanism and verified on the ground to further determine the accuracy of the position compensation method of the flexible cable drive mechanism.

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