Mechanism output torque control method based on electromechanical actuator

Abstract

The present application relates to a kind of mechanism output torque control method based on electromechanical actuator, belong to servo control technical field;Build electromechanical actuator transmission system;Drive the end of transmission mechanism to complete a complete motion process;The actuation distance of electromechanical actuator push rod and the angle of transmission mechanism end motion whole process relative to horizontal direction are measured, and relationship calibration is carried out;The thrust of electromechanical actuator and the torque of corresponding transmission mechanism end are calibrated;The thrust of electromechanical actuator and the input current data of electromechanical actuator are calibrated;Realize semi-closed loop control by controlling the input current of electromechanical actuator and the torque of transmission mechanism end;The present application adopts the way of fitting five-order polynomial model, realizes the indirect detection of load torque, solves the problem of accurate control output torque when there is no torque feedback.

Description

Technical Field

[0001] This invention belongs to the field of servo control technology and relates to a method for controlling the output torque of a mechanism based on an electromechanical actuator. Background Technology

[0002] For mechanisms based on electromechanical actuators to output torque, the method typically involves directly measuring the output torque as a feedback signal to correct the actuator's output force. When the output torque cannot be directly measured due to certain factors, a semi-closed-loop method is required. This involves indirectly detecting the output torque by detecting the force signal in the transmission link, comparing it with the original input torque value, and using the difference for control.

[0003] In existing technologies, semi-closed-loop torque control of electromechanical actuators is usually based on the kinematic and dynamic characteristics of the transmission mechanism itself, and is achieved through analytical calculation. Specifically, patent CN106840723 relates to a hydraulic rocker arm loading device and its loading method. This invention installs a tension / compression sensor at one end of a hydraulic linear actuator. Its advantage is that it can achieve real-time torque tracking based on the movement pattern of the servo motor connected to the rocker arm. However, its disadvantage is that the torque loaded by this method is calculated based on the kinematic and dynamic characteristics of the designed triangular rocker arm. If the actual shape and dimensions of the triangular rocker arm differ from the design, such as due to errors in processing or assembly, the actual torque output by the loading device will also have a significant error compared to the target, affecting the accuracy of torque loading. Furthermore, it can only output a fixed extension or retraction torque to the triangular rocker arm by judging whether the tension / compression sensor is subjected to tension or compression, and cannot output a real-time, arbitrary torque to the rocker arm. The patented six-bar linkage knee joint with knee torque control device, CN 1150868, controls the magnitude of friction torque by controlling the position of the friction cone in the knee joint torque control device. The advantage is that torque control can be performed without relying on sensors, and the structure is small and flexible. The disadvantage is that this torque control method is completely open-loop, and it is impossible to calculate the current output torque directly or indirectly through sensors. Therefore, it is impossible to output a given torque, let alone output a specific torque curve. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a mechanism output torque control method based on electromechanical actuators. By using a fitting fifth-order polynomial model, the load torque can be indirectly detected, thus solving the problem of accurately controlling the output torque when there is no torque feedback.

[0005] The solution of the present invention is:

[0006] A method for controlling the output torque of a mechanism based on an electromechanical actuator includes:

[0007] Step 1: Construct the electromechanical actuator transmission system, including an electromechanical actuator mounting base, tension / compression sensors, an electromechanical actuator, an electromechanical actuator push rod, a transmission mechanism linkage structure, a linkage structure mounting base, the transmission mechanism end, a first link, and a second link; through the reciprocating motion of the electromechanical actuator, the transmission mechanism end is driven to rotate sequentially via the electromechanical actuator push rod, the transmission mechanism linkage structure, the first link, and the second link;

[0008] Step 2: Drive the end of the transmission mechanism through the electromechanical actuator to complete one complete motion process; measure the actuation distance of the electromechanical actuator push rod and the angle of the end of the transmission mechanism relative to the horizontal direction during the entire motion process;

[0009] Step 3: Calibrate the relationship between the actuation distance of the electromechanical actuator push rod and the angle relative to the horizontal direction during the entire motion process of the transmission mechanism end;

[0010] Step 4: Based on the complete motion process in Step 2, obtain the thrust of the electromechanical actuator and the torque at the end of the transmission mechanism corresponding to the thrust, and obtain the input current data of the electromechanical actuator;

[0011] Step 5: Calibrate the relationship between the thrust of the electromechanical actuator in Step 4 and the torque at the end of the corresponding transmission mechanism;

[0012] Step 6: Calibrate the relationship between the thrust and input current data of the electromechanical actuator from Step 4;

[0013] Step 7: Based on the parameters calibrated in the above steps, obtain the thrust current coefficient K of the electromechanical actuator. The relationship between the input current of the electromechanical actuator and the torque at the end of the transmission mechanism obtained in Step 3 is used to achieve semi-closed-loop control by controlling the input current of the electromechanical actuator and the torque at the end of the transmission mechanism.

[0014] In the above-mentioned method for controlling the output torque of a mechanism based on an electromechanical actuator, the specific structure of the electromechanical actuator transmission system in step one is as follows:

[0015] One axial end of the electromechanical actuator is mounted on a horizontal fixed platform via an electromechanical actuator mounting base; a tension / compression sensor is mounted on the electromechanical actuator; the bottom of the transmission mechanism linkage structure is rotatably connected to the horizontal fixed platform via a linkage structure mounting base; the other axial end of the electromechanical actuator is rotatably connected to the transmission mechanism linkage structure via an electromechanical actuator push rod; one end of the second linkage is connected to the edge of the horizontal fixed platform; the other end of the second linkage is mounted on the end of the transmission mechanism; one end of the first linkage is rotatably connected to the transmission mechanism linkage structure; the other end of the first linkage is rotatably connected to the middle of the second linkage; the rotation center of the end of the transmission mechanism is the connection point between the second linkage and the edge of the horizontal fixed platform.

[0016] In the above-mentioned method for controlling the output torque of a mechanism based on an electromechanical actuator, in step two, the actuation distance of the electromechanical actuator push rod is calculated by the lead of the electromechanical actuator's lead screw and the motor rotation angle; the angle of the end of the transmission mechanism relative to the horizontal direction is measured by an external tilt sensor installed at the end of the transmission mechanism.

[0017] In the above-mentioned method for controlling the output torque of a mechanism based on an electromechanical actuator, in step three, the relationship between the actuation distance of the electromechanical actuator push rod and the angle relative to the horizontal direction during the entire motion of the transmission mechanism's end effector is as follows:

[0018] q = c5x 5 +c4x 4 +c3x 3 +c2x 2 +c1x+c0

[0019] In the formula, q is the angle of the end of the transmission mechanism relative to the horizontal direction;

[0020] x represents the actuation distance of the electromechanical actuator push rod;

[0021] c0, c1, c2, c3, c4, and c5 are the unknown coefficients of the fifth-degree polynomial;

[0022] Suppose x1, x2...x n Let q1, q2...q be the actuation distance of n sets of electromechanical actuator push rods. n For the n groups of corresponding 5 transmission mechanism ends relative to the horizontal direction, the unknown coefficients of the fifth-order polynomial are calculated using the Vandermonde matrix polynomial fitting method, specifically expressed as:

[0023]

[0024] This provides a clear understanding of the relationship between the actuation distance of the electromechanical actuator push rod and the angle relative to the horizontal direction during the entire motion of the transmission mechanism's end effector.

[0025] In the above-mentioned method for controlling the output torque of a mechanism based on an electromechanical actuator, in step four, the thrust of the electromechanical actuator is measured by a tension / compression sensor; the input current data of the electromechanical actuator is obtained by feedback from the actuator's driver.

[0026] In the aforementioned method for controlling the output torque of a mechanism based on an electromechanical actuator, the torque data at the end of the transmission mechanism is obtained by suspending a standard mass m at the end of the transmission mechanism and calculating the gravitational torque τ of the weight. Let g be the gravitational acceleration constant, and l be the actual length from the end of the transmission mechanism to the rotational center of the end of the transmission mechanism (measured by measurement). Then, the calculation method for the torque τ at the end of the transmission mechanism is as follows:

[0027] τ=mglcos(q)

[0028] The actual length from the end of the drive mechanism to the center of rotation of the transmission mechanism is obtained by measuring with vernier calipers.

[0029] In the above-mentioned method for controlling the output torque of a mechanism based on an electromechanical actuator, the method for calibrating the relationship between the thrust of the electromechanical actuator and the torque at the end of the corresponding transmission mechanism in step five is as follows:

[0030] The relationship between the thrust of the electromechanical actuator and the torque at the end of the corresponding transmission mechanism under that thrust is obtained by differentiating both sides of the fifth-degree polynomial equation with known coefficients obtained in step three with respect to time:

[0031]

[0032] Let η be the transmission efficiency of the transmission mechanism. According to the law of conservation of energy, we have:

[0033]

[0034] The equation relating the thrust of the electromechanical actuator to the torque at the end of the corresponding transmission mechanism is as follows:

[0035]

[0036] In the formula, τ is the torque at the end of the transmission mechanism;

[0037] F represents the thrust of the electromechanical actuator.

[0038] In the above-mentioned method for controlling the output torque of a mechanism based on an electromechanical actuator, the transmission efficiency η of the transmission mechanism is calculated using the thrust of the electromechanical actuator obtained in step three and the torque data at the end of the transmission mechanism corresponding to that thrust.

[0039]

[0040] In the aforementioned method for controlling the output torque of a mechanism based on an electromechanical actuator, step six involves calibrating the relationship between the actuator's thrust and its input current data as follows:

[0041] Let K be the thrust-current coefficient of the electromechanical actuator; then the relationship between the thrust and the input current of the electromechanical actuator is as follows:

[0042] F = Ki

[0043] In the formula, F is the thrust of the electromechanical actuator;

[0044] i represents the input current data.

[0045] In the above-mentioned method for controlling the output torque of a mechanism based on an electromechanical actuator, in step seven, the relationship between the input current of the electromechanical actuator and the torque at the end of the transmission mechanism is represented by the unknown coefficients c0, c1, c2, c3, c4, and c5 of the calibrated fifth-order polynomial, the transmission efficiency η, and the thrust current coefficient K of the electromechanical actuator:

[0046]

[0047] In the formula, τ is the torque at the end of the transmission mechanism;

[0048] η is the transmission efficiency of the transmission mechanism;

[0049] K is the thrust current coefficient of the electromechanical actuator;

[0050] i represents the input current data.

[0051] The advantages of this invention compared to the prior art are:

[0052] (1) The present invention adopts an experimental calibration and fitting method for the relationship between the input current of the electromechanical actuator, the push rod thrust, and the torque output at the end of the transmission mechanism. By controlling the input current of the electromechanical actuator, the torque output at the end of the transmission mechanism is controlled in a semi-closed loop. The intermediate links are ignored, and the relationship between the input current and the final output torque of the torque control system is directly established. The influence of mechanical structure shape and size error is eliminated, which effectively improves the accuracy of torque control.

[0053] (2) By establishing a functional relationship between the input current of the electromechanical actuator and the torque output at the end of the transmission mechanism, which includes a fifth-order polynomial, the present invention realizes real-time, arbitrary-size, and even specific-curve torque semi-closed-loop control, effectively improving the flexibility of torque output.

[0054] (3) The present invention introduces the Vandermonde matrix to fit the polynomial, which has a smaller computational cost and is simple and quick to implement compared with machine learning and other methods, effectively reducing the computational consumption of the system.

[0055] (4) In the calibration experiment, the present invention uses an external tilt sensor and weights to measure the end angle and output torque of the transmission mechanism respectively. After the calibration experiment is completed, it can be disassembled. In actual work, there is no need to install the above measuring device, which effectively reduces the overall volume and weight of the mechanism and makes the mechanism more concise.

[0056] (5) The present invention uses a fifth-order polynomial model to study the relationship between the actuation distance of the electromechanical actuator push rod and the end angle of the transmission mechanism, as well as the relationship between the actuator thrust and the torque output of the end of the transmission mechanism. Compared with the traditional second-order system model, it solves the problem of difficult dynamic modeling and solving of high-order systems and effectively improves the accuracy of torque control. Attached Figure Description

[0057] Figure 1 This is a flowchart illustrating the output torque control process of the mechanism based on the electromechanical actuator of the present invention.

[0058] Figure 2 This is a schematic diagram of the electromechanical actuator transmission system of the present invention;

[0059] Figure 3 This is a flowchart of the measurement data of the present invention. Detailed Implementation

[0060] The present invention will be further described below with reference to the embodiments.

[0061] This invention provides a mechanism output torque control method based on electromechanical actuators. It adopts a fitting fifth-order polynomial model to achieve indirect detection of load torque, thus solving the problem of accurate control of output torque when there is no torque feedback.

[0062] Mechanism output torque control methods based on electromechanical actuators, such as Figure 1 As shown, the specific steps include the following:

[0063] Step 1: Construct the electromechanical actuator transmission system, including electromechanical actuator mounting base 1, tension / compression sensor 2, electromechanical actuator 3, electromechanical actuator push rod 4, transmission mechanism linkage structure 5, linkage structure mounting base 6, transmission mechanism end 8, first link 9, and second link 10; through the reciprocating motion of the electromechanical actuator 3, the transmission mechanism end 8 is driven to rotate through the electromechanical actuator push rod 4, transmission mechanism linkage structure 5, first link 9, and second link 10 in sequence.

[0064] The specific structure of the electromechanical actuator transmission system is as follows:

[0065] One axial end of the electromechanical actuator 3 is mounted on a horizontal fixed platform via an electromechanical actuator mounting base 1; a tension / compression sensor 2 is mounted on the electromechanical actuator 3; the bottom of the transmission mechanism linkage structure 5 is rotatably connected to the horizontal fixed platform via a linkage structure mounting base 6; the other axial end of the electromechanical actuator 3 is rotatably connected to the transmission mechanism linkage structure 5 via an electromechanical actuator push rod 4; one end of the second linkage 10 is connected to the edge of the horizontal fixed platform; the other end of the second linkage 10 is mounted on the transmission mechanism end 8; one end of the first linkage 9 is rotatably connected to the transmission mechanism linkage structure 5; the other end of the first linkage 9 is rotatably connected to the middle of the second linkage 10; the rotation center of the transmission mechanism end 8 is the connection point between the second linkage 10 and the edge of the horizontal fixed platform, such as... Figure 2 As shown.

[0066] Step 2: The electromechanical actuator 3 drives the transmission mechanism end 8 to complete one complete motion process; measure the actuation distance of the electromechanical actuator push rod 4 and the angle of the transmission mechanism end 8 relative to the horizontal direction throughout the entire motion process, such as... Figure 3 As shown.

[0067] The actuation distance of the electromechanical actuator push rod 4 is calculated by the lead of the lead screw of the electromechanical actuator 3 and the motor rotation angle; the angle of the transmission mechanism end 8 relative to the horizontal direction is measured by an external tilt sensor installed at the transmission mechanism end 8.

[0068] Step 3: Calibrate the relationship between the actuation distance of the electromechanical actuator push rod 4 and the angle of the end of the transmission mechanism 8 relative to the horizontal direction throughout the entire movement process.

[0069] The relationship between the actuation distance of the electromechanical actuator push rod 4 and the angle relative to the horizontal direction during the entire movement of the transmission mechanism end 8 is as follows:

[0070] q = c5x 5 +c4x 4 +c3x 3 +c2x 2 +c1x+c0

[0071] In the formula, q is the angle of the end of the transmission mechanism 8 relative to the horizontal direction;

[0072] x represents the actuation distance of the electromechanical actuator push rod 4;

[0073] c0, c1, c2, c3, c4, and c5 are the unknown coefficients of the fifth-degree polynomial;

[0074] Suppose x1, x2...x n Let q1, q2...q be the actuation distance of n sets of electromechanical actuators and 3 push rods. n For the n groups of corresponding 5 transmission mechanism ends relative to the horizontal direction, the unknown coefficients of the fifth-order polynomial are calculated using the Vandermonde matrix polynomial fitting method, specifically expressed as:

[0075]

[0076] This provides a clear understanding of the relationship between the actuation distance of the electromechanical actuator push rod 4 and the angle relative to the horizontal direction during the entire motion of the transmission mechanism end 8.

[0077] Step 4: Based on the complete motion process in Step 2, obtain the thrust of the electromechanical actuator 3 and the torque of the transmission mechanism end 8 corresponding to the thrust, and obtain the input current data of the electromechanical actuator 3.

[0078] The thrust of the electromechanical actuator 3 is measured by the tension / compression sensor 2; the input current data of the electromechanical actuator 3 is obtained by feedback from the driver of the electromechanical actuator 3.

[0079] The torque data at the end of the transmission mechanism 8 is obtained by suspending a standard mass m at the end of the transmission mechanism 8 and calculating the gravitational torque τ of the weight; assuming g is the gravitational acceleration constant and l is the actual length from the end of the transmission mechanism 8 to the center of rotation of the end of the transmission mechanism 7 as measured, the calculation method for the torque τ at the end of the transmission mechanism 8 is as follows:

[0080] τ=mglcos(q)

[0081] The actual length of the rotational motion center at the end of the drive mechanism (8 to 7) is obtained by measuring with vernier calipers.

[0082] Step 5: Calibrate the relationship between the thrust of the electromechanical actuator 3 in Step 4 and the torque of the corresponding transmission mechanism end 8.

[0083] The method for calibrating the relationship between the thrust of the electromechanical actuator 3 and the torque at the end of the corresponding transmission mechanism 8 is as follows:

[0084] The relationship between the thrust of the electromechanical actuator 3 and the torque at the end of the transmission mechanism 8 corresponding to that thrust is obtained by differentiating both sides of the fifth-degree polynomial equation with known coefficients obtained in step three with respect to time:

[0085]

[0086] Let η be the transmission efficiency of the transmission mechanism. According to the law of conservation of energy, we have:

[0087]

[0088] The equation relating the thrust of the electromechanical actuator 3 to the torque at the end of the transmission mechanism 8 corresponding to that thrust is:

[0089]

[0090] In the formula, τ is the torque at the end of the transmission mechanism;

[0091] F represents the thrust of electromechanical actuator 3.

[0092] The transmission efficiency η of the transmission mechanism is calculated using the thrust of the electromechanical actuator 3 obtained in step three and the torque data at the end of the transmission mechanism 8 corresponding to that thrust.

[0093]

[0094] Step 6: Calibrate the relationship between the thrust and input current data of electromechanical actuator 3 from step 4.

[0095] The method for calibrating the relationship between the thrust and input current data of electromechanical actuator 3 is as follows:

[0096] Let K be the thrust-current coefficient of electromechanical actuator 3; then the relationship between the thrust of electromechanical actuator 3 and the input current data of electromechanical actuator 3 is as follows:

[0097] F = Ki

[0098] In the formula, F is the thrust of the electromechanical actuator 3;

[0099] i represents the input current data.

[0100] Step 7: Based on the parameters obtained from the above steps, the thrust current coefficient K of the electromechanical actuator 3 is obtained. The relationship between the input current of the electromechanical actuator 3 and the torque of the transmission mechanism end 8 is obtained from Step 3. Semi-closed-loop control is achieved by controlling the input current of the electromechanical actuator 3 and the torque of the transmission mechanism end 8.

[0101] The relationship between the input current of the electromechanical actuator 3 and the torque at the end of the transmission mechanism 8 is expressed by the unknown coefficients c0, c1, c2, c3, c4, and c5 of the calibrated fifth-order polynomial, the transmission efficiency η, and the thrust current coefficient K of the electromechanical actuator 3:

[0102]

[0103] In the formula, τ is the torque at the end of the transmission mechanism;

[0104] η is the transmission efficiency of the transmission mechanism;

[0105] K is the thrust current coefficient of electromechanical actuator 3;

[0106] i represents the input current data.

[0107] This invention employs an experimental calibration and fitting method to determine the relationship between the input current of the electromechanical actuator, the push rod thrust, and the torque output at the end of the transmission mechanism. By controlling the input current of the electromechanical actuator to perform semi-closed-loop control of the torque output at the end of the transmission mechanism, the intermediate links are ignored, and the relationship between the input current and the final output torque of the torque control system is directly established. The influence of mechanical structure shape and size errors is eliminated, which effectively improves the accuracy of torque control.

[0108] This invention establishes a functional relationship between the input current of the electromechanical actuator and the torque output at the end of the transmission mechanism, which includes a fifth-order polynomial. This enables real-time, arbitrary-size, and even specific-curve semi-closed-loop torque control, effectively improving the flexibility of torque output.

[0109] This invention introduces the Vandermonde matrix to fit the polynomial, which requires less computation than machine learning and is simple and quick to implement, effectively reducing the computational cost of the system.

[0110] In the calibration experiment, this invention uses an external tilt sensor and weights to measure the end angle and output torque of the transmission mechanism. After the calibration experiment is completed, the device can be disassembled. In actual work, there is no need to install the above measuring device, which effectively reduces the overall size and weight of the mechanism and makes the mechanism simpler.

[0111] This invention employs a fifth-order polynomial model to study the relationship between the actuation distance of the electromechanical actuator push rod and the end angle of the transmission mechanism, as well as the relationship between the actuator thrust and the torque output at the end of the transmission mechanism. Compared with the traditional second-order system model, this invention solves the problem of difficult dynamic modeling and solving of high-order systems, and effectively improves the accuracy of torque control.

[0112] This invention addresses a semi-closed-loop torque control system composed of electromechanical actuators and a transmission mechanism without torque feedback. It proposes a mechanism output torque control method based on electromechanical actuators. By fitting experimental measurement data with a fifth-order polynomial, a mapping model between the input current of the electromechanical actuator and the output torque at the end of the transmission mechanism is directly established, enabling dynamic prediction of the end load and solving the problem of accurate torque control without torque feedback.

[0113] This invention addresses the problems of difficulty in obtaining analytical solutions and inaccurate prediction models for nonlinear systems. It establishes a fifth-order polynomial model, introduces the Vandermonde matrix polynomial fitting method, and constructs a mapping model between the actuation distance of the electromechanical actuator and the end angle of the transmission mechanism. This enables accurate state characterization of complex nonlinear systems and solves the nonlinear control problem caused by mechanical transmission errors.

[0114] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method of controlling an output torque of a mechanism based on an electromechanical actuator, characterized by: The application relates to a method for calibrating a mechanical-electrical actuator transmission system. Step one: a mechanical-electrical actuator transmission system is built, which comprises a mechanical-electrical actuator fixing base (1), a tension and pressure sensor (2), a mechanical-electrical actuator (3), a mechanical-electrical actuator push rod (4), a transmission mechanism connecting rod structure (5), a connecting rod structure fixing base (6), a transmission mechanism terminal end (8), a first connecting rod (9) and a second connecting rod (10); through the reciprocating movement of the mechanical-electrical actuator (3), the mechanical-electrical actuator push rod (4), the transmission mechanism connecting rod structure (5), the first connecting rod (9) and the second connecting rod (10) are sequentially used to drive the transmission mechanism terminal end (8) to rotate; Step two: the mechanical-electrical actuator (3) drives the transmission mechanism terminal end (8) to complete a complete movement process; the actuation distance of the mechanical-electrical actuator push rod (4) and the angle of the transmission mechanism terminal end (8) relative to the horizontal direction in the whole movement process are measured; Step three: a five-order polynomial model is used to calibrate the relationship between the actuation distance of the mechanical-electrical actuator push rod (4) and the angle of the transmission mechanism terminal end (8) relative to the horizontal direction in the whole movement process; Step four: according to the complete movement process in step two, the pushing force of the mechanical-electrical actuator (3) and the torque of the transmission mechanism terminal end (8) corresponding to the pushing force are obtained, and input current data of the mechanical-electrical actuator (3) are obtained; Step five: the relationship between the pushing force of the mechanical-electrical actuator (3) and the torque of the transmission mechanism terminal end (8) in step four is calibrated; Step six: the relationship between the pushing force of the mechanical-electrical actuator (3) and the input current data of the mechanical-electrical actuator (3) in step four is calibrated; Step seven: according to the parameters calibrated in the above steps, the pushing force current coefficient K of the mechanical-electrical actuator (3) is obtained; and the relationship between the input current of the mechanical-electrical actuator (3) and the torque of the transmission mechanism terminal end (8) is obtained, so that semi-closed loop control is realized by controlling the input current of the mechanical-electrical actuator (3) and the torque of the transmission mechanism terminal end (8).

2. The method of claim 1, wherein the method is a method of controlling a torque output of an electromechanical actuator-based mechanism. In step one, the specific structure of the mechanical-electrical actuator transmission system is as follows: One end of the mechanical-electrical actuator (3) is installed on a horizontal fixed platform through the mechanical-electrical actuator fixing base (1); the tension and pressure sensor (2) is installed on the mechanical-electrical actuator (3); the bottom of the transmission mechanism connecting rod structure (5) is rotationally connected with the horizontal fixed platform through the connecting rod structure fixing base (6); the other end of the mechanical-electrical actuator (3) is rotationally connected with the transmission mechanism connecting rod structure (5) through the mechanical-electrical actuator push rod (4); one end of the second connecting rod (10) is connected with the edge of the horizontal fixed platform; the other end of the second connecting rod (10) is installed with the transmission mechanism terminal end (8); one end of the first connecting rod (9) is rotationally connected with the transmission mechanism connecting rod structure (5); the other end of the first connecting rod (9) is rotationally connected with the middle part of the second connecting rod (10); the rotation center of the transmission mechanism terminal end (8) is the connecting point of the second connecting rod (10) and the edge of the horizontal fixed platform.

3. The method of claim 2, wherein the method is a method of controlling a torque output of an electromechanical actuator-based mechanism. In step two, the actuation distance of the mechanical-electrical actuator push rod (4) is obtained by calculating the lead screw lead and the motor rotation angle of the mechanical-electrical actuator (3); the angle of the transmission mechanism terminal end (8) relative to the horizontal direction is obtained by measuring an external inclination sensor installed on the transmission mechanism terminal end (8).

4. The method of claim 3, wherein the method is characterized by: In the third step, the relationship between the actuation distance of the electromechanical actuator push rod (4) and the angle of the transmission mechanism end (8) relative to the horizontal direction during the entire movement process is as follows: q = c5x 5 + c4x 4 + c3x 3 + c2x 2 + c1x + c0 In the formula, q is the angle of the transmission mechanism end (8) relative to the horizontal direction; x is the actuation distance of the electromechanical actuator push rod (4); c0, c1, c2, c3, c4, and c5 are unknown coefficients of the quintic polynomial, respectively. Assume x1, x2...x n The actuation distance of the n groups of electromechanical actuators (3) push rods is q1, q2...q n The angle of the n groups of corresponding five transmission mechanism ends relative to the horizontal direction is five polynomials unknown coefficients, which are calculated by the method of polynomial fitting of Vandermonde matrix, and the specific expression is: Thus, the relationship between the actuation distance of the electromechanical actuator push rod (4) and the angle of the transmission mechanism end (8) relative to the horizontal direction during the entire movement process is obtained.

5. The method of claim 4, wherein the method is a method of controlling the output torque of an electromechanical actuator-based mechanism. In the fourth step, the thrust of the electromechanical actuator (3) is measured by the tension and compression force sensor (2); and the input current data of the electromechanical actuator (3) is obtained by the feedback of the driver of the electromechanical actuator (3).

6. The method of claim 5, wherein the method is a method of controlling a torque output of an electromechanical actuator-based mechanism. The torque data of the transmission mechanism end (8) is obtained by hanging a standard mass of m at the transmission mechanism end (8), and calculating the gravity torque τ of the mass; setting g as the gravitational acceleration constant, and l as the actual length from the transmission mechanism end (8) to the center of rotation of the transmission mechanism end, the calculation method of the torque τ of the transmission mechanism end (8) is as follows: τ = mglcos(q) The actual length from the transmission mechanism end (8) to the center of rotation of the transmission mechanism end is measured by a vernier caliper.

7. The method of controlling the output torque of a mechanism based on an electromechanical actuator according to claim 4, characterized by: In the fifth step, the relationship calibration method between the thrust of the electromechanical actuator (3) and the torque of the corresponding transmission mechanism end (8) is as follows: The relationship between the thrust of the electromechanical actuator (3) and the torque of the corresponding transmission mechanism end (8) under the thrust is obtained by deriving the quintic polynomial equation with known coefficients in the third step: Setting η as the transmission efficiency of the transmission mechanism, according to the law of conservation of energy, we have: The relationship equation between the thrust of the electromechanical actuator (3) and the torque of the corresponding transmission mechanism end (8) under the thrust is obtained as follows: In the formula, τ is the torque of the transmission mechanism end (8); F is the thrust of the electromechanical actuator (3).

8. The method of claim 7, wherein the method is a method of controlling a torque output of an electromechanical actuator-based mechanism. The transmission efficiency η of the transmission mechanism is calculated by the thrust of the electromechanical actuator (3) and the torque data of the corresponding transmission mechanism end (8) under the thrust obtained in the fourth step.

9. The method of claim 2, wherein the method is a method of controlling the output torque of an electromechanical actuator-based mechanism. In the sixth step, the relationship calibration method between the thrust of the electromechanical actuator (3) and the input current data of the electromechanical actuator (3) is as follows: Setting K as the thrust current coefficient of the electromechanical actuator (3); the relationship between the thrust of the electromechanical actuator (3) and the input current data of the electromechanical actuator (3) is as follows: F = Ki In the formula, F is the thrust of the electromechanical actuator (3); i is the input current data.

10. The method of claim 4, wherein the method is a method of controlling the output torque of an electromechanical actuator-based mechanism. In the seventh step, the relationship between the input current of the electromechanical actuator (3) and the torque of the transmission mechanism end (8) is represented by the unknown coefficients c0, c1, c2, c3, c4, and c5 of the quintic polynomial obtained by calibration, the transmission efficiency η, and the thrust current coefficient K of the electromechanical actuator (3) as follows: In the formula, τ is the torque of the transmission mechanism end (8); η is the transmission efficiency of the transmission mechanism; K is the thrust current coefficient of the electromechanical actuator (3); i is the input current data.

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