Joint motor control method and device, robot and storage medium

Abstract

The present disclosure relates to a joint motor control method and device, a robot and a storage medium. The method comprises: determining a desired joint torque according to a desired joint state and an actual joint state in a motion control instruction; inputting the desired joint torque, an actual joint torque fed back by the joint motor and an actual cross-axis current into a finite time convergence model to obtain a cross-axis control voltage output by the finite time convergence model, wherein the finite time convergence model is a model constructed according to a relative relationship between at least two of an electromagnetic torque, a cross-axis current, a direct-axis current and a cross-axis voltage; and controlling the joint motor to move according to the cross-axis control voltage and a preset direct-axis control current.

Description

Technical Field

[0001] This disclosure relates to the field of robotics technology, specifically to a joint motor control method, device, robot, and storage medium. Background Technology

[0002] In recent years, robotics technology has continuously developed, becoming increasingly intelligent and automated, with improvements in the richness, stability, and flexibility of its movements. Bionic robots have multiple joints, each equipped with a joint motor. These joint motors drive relative movement between the parts on either side of the joint, enabling the robot to perform various actions. However, in related technologies, the control efficiency of robot joint motors is relatively low, especially under complex working conditions where convergence is often difficult, preventing the robot from completing more complex movements. Summary of the Invention

[0003] To overcome the problems existing in the related technologies, this disclosure provides a joint motor control method, device, robot, and storage medium to solve the defects in the related technologies.

[0004] According to a first aspect of the present disclosure, a joint motor control method is provided, the method comprising: The desired joint torque is determined based on the desired joint state and the actual joint state in the motion control command. The desired joint torque, the actual joint torque fed back by the joint motor, and the actual cross-axis current are input into the finite-time convergence model to obtain the cross-axis control voltage output by the finite-time convergence model. The finite-time convergence model is a model constructed based on the relative relationship between at least two of the electromagnetic torque, cross-axis current, direct-axis current, and cross-axis voltage. The joint motor is controlled to move according to the quadrature axis control voltage and the preset direct axis control current.

[0005] In one possible embodiment of this disclosure, the finite-time convergence model is used to ensure that the error between the desired joint torque and the actual joint torque converges within a finite time; the method further includes: Construct the finite-time convergent model based on at least one of the following relationships: The relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

[0006] In one possible embodiment of this disclosure, constructing the finite-time convergence model based on at least one of the following relationships includes: Using the superspiral sliding mode dynamic convergence model, construct the finite-time convergence model according to at least one of the following: The relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

[0007] In one possible embodiment of this disclosure, determining the desired joint torque based on the desired joint state and the actual joint state in the motion control command includes: The desired joint state and the actual joint state are input to the impedance controller to obtain the desired joint torque output by the impedance controller.

[0008] In one possible embodiment of this disclosure, the desired joint state includes a desired joint position and a desired joint velocity; and / or, The actual joint state includes the actual joint position and the actual joint velocity.

[0009] In one possible embodiment of this disclosure, controlling the joint motor to move according to the quadrature axis control voltage and the preset direct axis control current includes: The direct-axis control current and the actual direct-axis current are input to the current loop direct-axis controller to obtain the direct-axis control voltage output by the current loop direct-axis controller; The joint motor is driven to move according to the quadrature axis control voltage and the direct axis control voltage.

[0010] In one possible embodiment of this disclosure, the method further includes: The actual joint state, the actual joint torque, the actual cross-axis current, and the actual direct-axis current fed back by the joint motor are obtained.

[0011] According to a second aspect of the present disclosure, a joint motor control device is provided, the device comprising: The torque module is used to determine the desired joint torque based on the desired joint state and the actual joint state in the motion control command. A voltage module is used to input the desired joint torque, the actual joint torque fed back by the joint motor, and the actual quadrature axis current into a finite-time convergence model to obtain the quadrature axis control voltage output by the finite-time convergence model. The finite-time convergence model is a model constructed based on the relative relationship between at least two of the electromagnetic torque, quadrature axis current, direct axis current, and quadrature axis voltage. The motion module is used to control the joint motor to move according to the quadrature axis control voltage and the preset direct axis control current.

[0012] In one possible embodiment of this disclosure, the finite-time convergence model is used for: Construct the finite-time convergent model based on at least one of the following relationships: The relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

[0013] In one possible embodiment of this disclosure, the voltage module is used for: Using the superspiral sliding mode dynamic convergence model, the finite-time convergence model is constructed based on at least one of the following relative relationships: The relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

[0014] In one possible embodiment of this disclosure, the torque module is used for: The desired joint state and the actual joint state are input to the impedance controller to obtain the desired joint torque output by the impedance controller.

[0015] In one possible embodiment of this disclosure, the desired joint state includes a desired joint position and a desired joint velocity; and / or, The actual joint state includes the actual joint position and the actual joint velocity.

[0016] In one possible embodiment of this disclosure, the motion module is used for: The direct-axis control current and the actual direct-axis current are input to the current loop direct-axis controller to obtain the direct-axis control voltage output by the current loop direct-axis controller; The joint motor is driven to move according to the quadrature axis control voltage and the direct axis control voltage.

[0017] In one possible embodiment of this disclosure, the apparatus further includes an acquisition module, the acquisition module being configured to: The actual joint state, the actual joint torque, the actual cross-axis current, and the actual direct-axis current fed back by the joint motor are obtained.

[0018] According to a third aspect of the present disclosure, a robot is provided, the robot including a memory and a processor, the memory being used to store computer instructions executable on the processor, and the processor being used to implement the joint motor control method of the first aspect when executing the computer instructions.

[0019] According to a fourth aspect of the present disclosure, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect.

[0020] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects: The joint motor control method provided in this disclosure first determines the desired joint torque based on the desired joint state and the actual joint state in the motion control command. Then, the desired joint torque, the actual joint torque fed back by the joint motor, and the actual cross-axis current are input to a finite-time convergence model to obtain the cross-axis control voltage output by the finite-time convergence model. Finally, the joint motor is controlled to move according to the cross-axis control voltage and the preset direct-axis control current. Since the finite-time convergence model is constructed based on the relative relationship between at least two of the electromagnetic torque, cross-axis current, direct-axis current, and cross-axis voltage, it can achieve torque control convergence within a finite time, especially under complex working conditions. Therefore, it can still maintain the frequency of torque control under complex working conditions, improving the control efficiency, stability, and motion complexity of the robot. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0022] Figure 1 This is a flowchart illustrating a joint motor control method according to an exemplary embodiment of this disclosure; Figure 2 This is a flowchart illustrating a joint motor control method according to an exemplary embodiment of this disclosure; Figure 3 This is a schematic diagram of the structure of a joint motor control device shown in an exemplary embodiment of the present disclosure; Figure 4 This is a structural block diagram of a robot illustrated in an exemplary embodiment of this disclosure. Detailed Implementation

[0023] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0024] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0025] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0026] In recent years, robotics technology has continuously developed, becoming increasingly intelligent and automated, with improvements in the richness, stability, and flexibility of its movements. Bionic robots have multiple joints, each equipped with a joint motor. These joint motors drive relative movement between the parts on either side of the joint, enabling the robot to perform various actions. However, in related technologies, the control efficiency of robot joint motors is relatively low, especially under complex working conditions where convergence is often difficult, preventing the robot from completing more complex movements.

[0027] Based on this, in a first aspect, at least one embodiment of this disclosure provides a joint motor control method, please refer to the appendix. Figure 1 It illustrates the process of the method, including steps S101 to S103.

[0028] This method can be applied to robots, such as bipedal or quadrupedal robots. The robot has multiple joints, each equipped with a joint motor. This method can be applied to each joint motor of the robot, that is, to drive the joint motor to move in order to complete the desired joint state obtained by the upper-level motion control based on the desired action.

[0029] In step S101, the desired joint torque is determined based on the desired joint state and the actual joint state in the motion control command.

[0030] The desired joint state can be the joint state controlled by this method, determined by the upper-level motion control based on the robot's desired action. The joint motors can feed back the joint state at a certain frequency during movement; this state is recorded as the actual joint state. Therefore, the actual joint state fed back by the joint motors can be obtained before executing this step. The joint torque is the torque of the joint motors, and the desired joint torque refers to the torque that the joint motors are expected to achieve.

[0031] For example, an impedance controller can be used to determine the desired joint torque. In this step, the desired joint state and the actual joint state are input to the impedance controller to obtain the desired joint torque output by the impedance controller. For instance, the desired joint state includes the desired joint position and the desired joint velocity, and the actual joint state includes the actual joint position and the actual joint velocity. A position error can be determined based on the desired joint position and the actual joint position, and a velocity error can be determined based on the desired joint velocity and the actual joint velocity. Then, the position error and velocity error are input to the impedance controller. The impedance controller can determine the desired joint torque based on the position error and velocity error, combined with its internal parameters and feedforward torque, etc.

[0032] In step S102, the desired joint torque, the actual joint torque fed back by the joint motor, and the actual cross-axis current are input to the finite-time convergence model to obtain the cross-axis control voltage output by the finite-time convergence model. The finite-time convergence model is a model constructed based on the relative relationship between at least two of the electromagnetic torque, cross-axis current, direct-axis current, and cross-axis voltage.

[0033] Optionally, before performing this step, the actual joint torque and actual quadrature-axis current fed back by the joint motor can be obtained. The joint torque is the torque of the joint motor, and the actual joint torque refers to the actual torque achieved by the joint motor. The actual quadrature-axis current is the actual current value on the quadrature axis of the armature winding.

[0034] The quadrature axis control voltage is the voltage value that is expected to be achieved on the quadrature axis of the armature winding.

[0035] The finite-time convergence model is used to ensure that the error between the desired joint torque and the actual joint torque converges within a finite time, that is, to ensure that the torque control converges. The finite-time convergence model can be pre-constructed based on at least one of the following relative relationships: The first item is the relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The second item is the relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

[0036] The content of the first term can be represented by the following formula 1:

[0037] In the formula, It is an electromagnetic torque. The permanent magnet torque of a permanent magnet synchronous motor. For the reluctance torque of a permanent magnet synchronous motor, For extreme logarithms, It is a permanent magnet flux chain. It is a direct-axis inductor. It is a quadrature axis inductor. For direct-axis current, It is the quadrature-axis current.

[0038] The content of the second item can be expressed using the following formula 2:

[0039] In the formula, It is the quadrature axis voltage. For motor resistance, This refers to the motor speed; The torque tracking error can be defined as Equation 3 below.

[0040] Furthermore, based on Equation 3 and Equation 1 above, we obtain Equation 4 as follows:

[0041] Therefore, based on Equations 2 and 4 above, we obtain Equation 5 as follows:

[0042] In the formula, , .

[0043] Furthermore, when constructing a finite-time convergence model using Equations 1 to 5 above, a super-spiral sliding mode dynamic convergence model can be used to construct the finite-time convergence model based on at least one of the above relative relationships.

[0044] For example, the dynamic convergence model of the superspiral sliding mode is as follows: Equation 6:

[0045] In the formula, , , For state variables, Differentiable.

[0046] If state v converges in finite time, the toroidal surface can be defined as follows: Therefore, based on Equation 6 above, the control law for the model shown in Equation 5 above is designed as follows (Equation 7), resulting in the finite-time convergence model:

[0047] In the formula, , It is a constant.

[0048] In step S103, the joint motor is controlled to move according to the quadrature axis control voltage and the preset direct axis control current (e.g., 0).

[0049] The direct-axis control current is the desired current value to be achieved on the direct axis of the armature winding.

[0050] For example, this step can be performed as follows: First, the direct-axis control current and the actual direct-axis current are input to the current loop direct-axis controller to obtain the direct-axis control voltage output by the current loop direct-axis controller. Before this step, the actual direct-axis current fed back by the articulated motor can be obtained. The actual direct-axis current is the actual current value on the direct axis of the armature winding. The direct-axis control voltage is the voltage value expected to be achieved on the direct axis of the armature winding.

[0051] Next, the joint motor is driven to move according to the quadrature axis control voltage and the direct axis control voltage.

[0052] Please refer to the appendix. Figure 2 The example illustrates a flowchart of a joint motor control method obtained by combining the above-described embodiments. In this method, the upper-level motion control sends the desired joint position. Expected joint velocity Impedance controller parameters and feedback torque Combined with the actual joint position fed back by the joint motor and the actual speed of the joint The desired joint torque is obtained through an impedance controller. . The actual joint torque fed back by the torque sensor Error between And the actual cross-axis current fed back by the joint motor. The quadrature axis control voltage is obtained through a finite-time convergence model. Preset (For example, 0) Combined with the actual direct-axis current fed back by the joint motor The direct-axis control voltage is obtained through the direct-axis current loop controller. . and The three-phase voltage obtained through pulse width modulation is used to drive the motor through the inverter.

[0053] The joint motor control method provided in this disclosure first determines the desired joint torque based on the desired joint state and the actual joint state in the motion control command. Then, the desired joint torque, the actual joint torque, and the actual cross-axis current are input to a finite-time convergence model to obtain the cross-axis control voltage output by the finite-time convergence model. Finally, the joint motor is controlled to move according to the cross-axis control voltage and the preset direct-axis control current. Since the finite-time convergence model is constructed based on the relative relationship between electromagnetic torque, cross-axis current, direct-axis current, and cross-axis voltage, it can achieve torque control convergence within a finite time, especially under complex working conditions. Therefore, it can still maintain the frequency of torque control under complex working conditions, improving the control efficiency, stability, and motion complexity of the motor and robot.

[0054] Compared to the traditional torque loop hierarchical control, this method adjusts the output to quadrature axis control voltage through model transformation, which simplifies control design, reduces controller parameters, and alleviates the burden of debugging and maintenance.

[0055] According to a second aspect of the embodiments of this disclosure, a joint motor control device is provided; please refer to the appendix. Figure 3 The device includes: The torque module 301 is used to determine the desired joint torque based on the desired joint state and the actual joint state in the motion control command. Voltage module 302 is used to input the desired joint torque, the actual joint torque fed back by the joint motor, and the actual cross-axis current into a finite-time convergence model to obtain the cross-axis control voltage output by the finite-time convergence model. The finite-time convergence model is a model constructed based on the relative relationship between at least two of the electromagnetic torque, cross-axis current, direct-axis current, and cross-axis voltage. The motion module 303 is used to control the joint motor to move according to the quadrature axis control voltage and the preset direct axis control current.

[0056] In one possible embodiment of this disclosure, the finite-time convergence model is used for: Construct the finite-time convergent model based on at least one of the following: The relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

[0057] In one possible embodiment of this disclosure, the voltage module is used for: Using the superspiral sliding mode dynamic convergence model, construct the finite-time convergence model according to at least one of the following: The relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

[0058] In one possible embodiment of this disclosure, the torque module is used for: The desired joint state and the actual joint state are input to the impedance controller to obtain the desired joint torque output by the impedance controller.

[0059] In one possible embodiment of this disclosure, the desired joint state includes a desired joint position and a desired joint velocity; and / or, The actual joint state includes the actual joint position and the actual joint velocity.

[0060] In one possible embodiment of this disclosure, the motion module is used for: The direct-axis control current and the actual direct-axis current are input to the current loop direct-axis controller to obtain the direct-axis control voltage output by the current loop direct-axis controller; The joint motor is driven to move according to the quadrature axis control voltage and the direct axis control voltage.

[0061] In one possible embodiment of this disclosure, the apparatus further includes an acquisition module, the acquisition module being configured to: The actual joint state, the actual joint torque, the actual cross-axis current, and the actual direct-axis current fed back by the joint motor are obtained.

[0062] Thirdly, at least one embodiment of this disclosure provides a robot, please refer to the appendix. Figure 4 The diagram illustrates the structure of the robot, which includes a memory and a processor. The memory stores computer instructions that can run on the processor, and the processor controls the joint motors based on the method described in any of the first aspects when executing the computer instructions.

[0063] Fourthly, at least one embodiment of this disclosure provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in any of the first aspects.

[0064] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0065] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A joint motor control method, characterized in that, The method includes: The desired joint torque is determined based on the desired joint state and the actual joint state in the motion control command. The desired joint torque, the actual joint torque fed back by the joint motor, and the actual cross-axis current are input into the finite-time convergence model to obtain the cross-axis control voltage output by the finite-time convergence model. The finite-time convergence model is a model constructed based on the relative relationship between at least two of the electromagnetic torque, cross-axis current, direct-axis current, and cross-axis voltage. The joint motor is controlled to move according to the quadrature axis control voltage and the preset direct axis control current.

2. The joint motor control method according to claim 1, characterized in that, The finite-time convergence model is used to ensure that the error between the desired joint torque and the actual joint torque converges within a finite time; the method further includes: Construct the finite-time convergent model based on at least one of the following relationships: The relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

3. The joint motor control method according to claim 1, characterized in that, The construction of the finite-time convergence model based on at least one of the following includes: Using the superspiral sliding mode dynamic convergence model, the finite-time convergence model is constructed based on at least one of the following relative relationships: The relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

4. The joint motor control method according to claim 1, characterized in that, The step of determining the desired joint torque based on the desired joint state and the actual joint state in the motion control command includes: The desired joint state and the actual joint state are input to the impedance controller to obtain the desired joint torque output by the impedance controller.

5. The joint motor control method according to claim 1 or 4, characterized in that, The desired joint state includes the desired joint position and the desired joint velocity; and / or, The actual joint state includes the actual joint position and the actual joint velocity.

6. The joint motor control method according to claim 1, characterized in that, The step of controlling the joint motor to move according to the quadrature axis control voltage and the preset direct axis control current includes: The direct-axis control current and the actual direct-axis current are input to the current loop direct-axis controller to obtain the direct-axis control voltage output by the current loop direct-axis controller; The joint motor is driven to move according to the quadrature axis control voltage and the direct axis control voltage.

7. The joint motor control method according to claim 6, characterized in that, The method further includes: The actual joint state, the actual joint torque, the actual cross-axis current, and the actual direct-axis current fed back by the joint motor are obtained.

8. A joint motor control device, characterized in that, The device includes: The torque module is used to determine the desired joint torque based on the desired joint state and the actual joint state in the motion control command. A voltage module is used to input the desired joint torque, the actual joint torque fed back by the joint motor, and the actual quadrature axis current into a finite-time convergence model to obtain the quadrature axis control voltage output by the finite-time convergence model. The finite-time convergence model is a model constructed based on the relative relationship between at least two of the electromagnetic torque, quadrature axis current, direct axis current, and quadrature axis voltage. The motion module is used to control the joint motor to move according to the quadrature axis control voltage and the preset direct axis control current.

9. The joint motor control device according to claim 8, characterized in that, The finite-time convergence model is used for: Construct the finite-time convergent model based on at least one of the following relationships: The relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

10. The joint motor control device according to claim 8, characterized in that, The voltage module is used for: Using the superspiral sliding mode dynamic convergence model, the finite-time convergence model is constructed based on at least one of the following relative relationships: The relative relationship between the electromagnetic torque and the quadrature-axis current and the direct-axis current; The relative relationship between the derivative of the quadrature-axis current and the quadrature-axis current, the direct-axis current, and the quadrature-axis voltage.

11. The joint motor control device according to claim 8, characterized in that, The torque module is used for: The desired joint state and the actual joint state are input to the impedance controller to obtain the desired joint torque output by the impedance controller.

12. The joint motor control device according to claim 8 or 11, characterized in that, The desired joint state includes the desired joint position and the desired joint velocity; and / or, The actual joint state includes the actual joint position and the actual joint velocity.

13. The joint motor control device according to claim 8, characterized in that, The motion module is used for: The direct-axis control current and the actual direct-axis current are input to the current loop direct-axis controller to obtain the direct-axis control voltage output by the current loop direct-axis controller; The joint motor is driven to move according to the quadrature axis control voltage and the direct axis control voltage.

14. The joint motor control device according to claim 13, characterized in that, The device further includes an acquisition module, the acquisition module being used for: The actual joint state, the actual joint torque, the actual cross-axis current, and the actual direct-axis current fed back by the joint motor are obtained.

15. A robot, characterized in that, The robot includes a memory and a processor. The memory is used to store computer instructions that can be executed on the processor. The processor is used to implement the joint motor control method of any one of claims 1 to 7 when executing the computer instructions.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method of any one of claims 1 to 7.

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