CN118106945A - Mechanical arm control method and device, mechanical arm and readable storage medium - Google Patents

Abstract

The disclosure provides a mechanical arm control method, a device, a mechanical arm and a readable storage medium, wherein the method comprises the following steps: and determining the speed control quantity of the tail end of the mechanical arm according to the relative position relation between the current position of the tail end of the mechanical arm and the expected position, the expected speed and the singular position weight, and determining the speed control quantity of the joint of the mechanical arm and the position control quantity of the joint of the mechanical arm so as to control the movement of the mechanical arm. According to the method and the device, the mechanical arm can obtain a determined joint control parameter in each control period, gradual convergence is carried out in a plurality of control periods, calculation time consumption in a single control period is reduced, in addition, negative influences of singular positions of the mechanical arm on solving failure and the like caused by inverse solution process are reduced through the singular position weight, and reliability of an inverse solution calculation result is improved.

Description

Mechanical arm control method and device, mechanical arm and readable storage medium

Technical Field

The disclosure relates to the technical field of mechanical arms, and in particular relates to a mechanical arm control method, a device, a mechanical arm and a readable storage medium.

Background

The current mechanical arm control method is mainly based on inverse solution of the input mechanical arm tail end control parameters so as to obtain the control parameters of the mechanical arm joints. The numerical inverse method is used as a common inverse method because of the advantage of independent mechanical arm joint configuration. However, in the numerical inversion method of the mechanical arm, since a plurality of inverse solution calculations are required in a single control cycle, the calculation is time-consuming, and when the mechanical arm approaches the odd-ectopic type, a maximum value is generated, resulting in failure of the inverse solution.

Disclosure of Invention

Accordingly, the present disclosure provides a method and apparatus for controlling a robot arm, and a readable storage medium, which at least solve the problems in the related art.

According to a first aspect of an embodiment of the present disclosure, there is provided a method for controlling a mechanical arm, the method including:

acquiring a desired position of the tail end of the mechanical arm and a desired speed when the tail end of the mechanical arm is positioned at the desired position;

Determining the speed control quantity of the tail end of the mechanical arm according to the relative position relation between the current position of the tail end of the mechanical arm and the expected position, the expected speed and the singular position weight, wherein the singular position weight is related to the current joint position type of the mechanical arm;

Determining the speed control quantity of the mechanical arm joint according to the speed control quantity of the tail end of the mechanical arm;

determining the position control quantity of the mechanical arm joint according to the current joint position of the mechanical arm and the speed control quantity of the mechanical arm joint;

and controlling the movement of the mechanical arm according to the speed control quantity and the position control quantity of the mechanical arm joint.

In combination with any one of the embodiments of the present disclosure, before determining the speed control amount of the robot arm tip according to the relative positional relationship of the current position of the robot arm tip and the desired position, the desired speed, and the singular position weight, the method further includes:

determining the maximum space position which can be reached by the mechanical arm according to the maximum length of the mechanical arm and preset boundary weight;

In response to the desired position exceeding the maximum spatial position, the desired position is corrected to bring the desired position within the maximum spatial position.

In combination with any one of the embodiments of the present disclosure, before determining the speed control amount of the robot arm tip according to the relative positional relationship of the current position of the robot arm tip and the desired position, the desired speed, and the singular position weight, the method further includes:

Acquiring a preset working space position of the mechanical arm;

in response to the desired position exceeding the workspace position, the desired position is corrected to bring the desired position within the workspace position.

In combination with any of the embodiments of the present disclosure, the method further comprises:

responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, wherein the singular position weight is zero;

responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type and smaller than or equal to the maximum singular value of the mechanical arm in the singular position type, wherein the singular position weight and the singular value of the current joint position type are in positive correlation;

Responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is larger than the maximum singular value of the mechanical arm in the singular position type, wherein the singular position weight is one;

The singular values are determined according to a jacobian matrix representing a mapping relation between joint positions of the mechanical arm and speed control quantity of the tail end of the mechanical arm and speed control quantity of joints of the mechanical arm.

In combination with any one of the embodiments of the present disclosure, before determining the speed control amount of the robot arm tip according to the relative positional relationship of the current position of the robot arm tip and the desired position, the desired speed, and the singular position weight, the method further includes:

and correcting the relative position relation to enable the relative position relation to be within the preset position threshold value in response to the relative position relation exceeding the preset position threshold value.

In combination with any one of the embodiments of the present disclosure, the determining the speed control amount of the mechanical arm joint according to the speed control amount of the mechanical arm end includes:

Determining the speed control quantity of the mechanical arm joint according to the speed control quantity of the tail end of the mechanical arm based on the jacobian matrix and the matrix damping value;

The method comprises the steps that in response to the fact that the minimum singular value of the mechanical arm in the current joint position type is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, the matrix damping value and the singular value of the current joint position type are in a negative correlation;

the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type, and the matrix damping value is zero;

The singular values are determined according to a jacobian matrix representing a mapping relationship between joint positions of the mechanical arm and speed control amounts of the tail end of the mechanical arm and the joints of the mechanical arm.

In combination with any one of the embodiments of the present disclosure, before determining the position control amount of the robot arm joint according to the current joint position of the robot arm, the method further includes:

Determining the limiting speed of a joint of the mechanical arm according to a jacobian matrix, the degree of freedom of the mechanical arm and at least one joint position of the mechanical arm, wherein the jacobian matrix represents a mapping relation between the speed control quantity of the tail end of the mechanical arm and the speed control quantity of the joint of the mechanical arm;

and updating the speed control quantity of the mechanical arm joint according to the limit speed.

In combination with any one of the embodiments of the present disclosure, the at least one joint position of the robotic arm includes an upper boundary position of the robotic arm joint, a lower boundary position of the robotic arm joint, and a midpoint position of the robotic arm joint.

In combination with any one of the embodiments of the present disclosure, the speed control amount of the end of the mechanical arm characterizes the moving speed of the end of the mechanical arm in the current control period;

The speed control amount of the mechanical arm joint characterizes the moving speed of the mechanical arm joint in the current control period;

The position control amount of the mechanical arm joint indicates the movement position of the mechanical arm joint in the current control period.

According to a second aspect of embodiments of the present disclosure, there is provided a robot arm control device, the device including:

The parameter acquisition module is used for: acquiring a desired position of the tail end of the mechanical arm and a desired speed when the tail end of the mechanical arm is positioned at the desired position;

An end speed determination module for: determining the speed control quantity of the tail end of the mechanical arm according to the relative position relation between the current position of the tail end of the mechanical arm and the expected position, the expected speed and the singular position weight, wherein the singular position weight is related to the current joint position type of the mechanical arm;

A joint velocity determination module for: determining the speed control quantity of the mechanical arm joint according to the speed control quantity of the tail end of the mechanical arm;

A joint position determination module for: determining the position control quantity of the mechanical arm joint according to the current joint position of the mechanical arm and the speed control quantity of the mechanical arm joint;

The mechanical arm control module is used for: and controlling the movement of the mechanical arm according to the speed control quantity and the position control quantity of the mechanical arm joint.

In combination with any one of the embodiments of the present disclosure, before determining the speed control amount of the tail end of the mechanical arm according to the relative positional relationship between the current position and the desired position of the tail end of the mechanical arm, the desired speed and the singular position weight, the apparatus further includes a first limiting module configured to:

determining the maximum space position which can be reached by the mechanical arm according to the maximum length of the mechanical arm and preset boundary weight;

In response to the desired position exceeding the maximum spatial position, the desired position is corrected to bring the desired position within the maximum spatial position.

In combination with any one of the embodiments of the present disclosure, before determining the speed control amount of the tail end of the mechanical arm according to the relative positional relationship between the current position and the desired position of the tail end of the mechanical arm, the desired speed and the singular position weight, the device further includes a second limiting module, configured to:

Acquiring a preset working space position of the mechanical arm;

in response to the desired position exceeding the workspace position, the desired position is corrected to bring the desired position within the workspace position.

In combination with any of the embodiments of the present disclosure, the apparatus further includes a weight determination module for:

responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, wherein the singular position weight is zero;

responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type and smaller than or equal to the maximum singular value of the mechanical arm in the singular position type, wherein the singular position weight and the singular value of the current joint position type are in positive correlation;

Responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is larger than the maximum singular value of the mechanical arm in the singular position type, wherein the singular position weight is one;

The singular values are determined according to a jacobian matrix representing a mapping relation between joint positions of the mechanical arm and speed control quantity of the tail end of the mechanical arm and speed control quantity of joints of the mechanical arm.

In combination with any one of the embodiments of the present disclosure, before determining the speed control amount of the robot arm end according to the relative positional relationship between the current position of the robot arm end and the desired position, the desired speed and the singular position weight, the apparatus further includes an error correction module configured to:

and correcting the relative position relation to enable the relative position relation to be within the preset position threshold value in response to the relative position relation exceeding the preset position threshold value.

In combination with any one of the embodiments of the present disclosure, when the joint speed determining module determines a speed control amount of a robot joint according to a speed control amount of a robot end, the joint speed determining module is specifically configured to:

Determining the speed control quantity of the mechanical arm joint according to the speed control quantity of the tail end of the mechanical arm based on the jacobian matrix and the matrix damping value;

The method comprises the steps that in response to the fact that the minimum singular value of the mechanical arm in the current joint position type is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, the matrix damping value and the singular value of the current joint position type are in a negative correlation;

the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type, and the matrix damping value is zero;

The singular values are determined according to a jacobian matrix representing a mapping relationship between joint positions of the mechanical arm and speed control amounts of the tail end of the mechanical arm and the joints of the mechanical arm.

In combination with any one of the embodiments of the present disclosure, before determining the position control amount of the mechanical arm joint according to the current joint position of the mechanical arm, the apparatus further includes a third limiting module configured to:

Determining the limiting speed of a joint of the mechanical arm according to a jacobian matrix, the degree of freedom of the mechanical arm and at least one joint position of the mechanical arm, wherein the jacobian matrix represents a mapping relation between the speed control quantity of the tail end of the mechanical arm and the speed control quantity of the joint of the mechanical arm;

and updating the speed control quantity of the mechanical arm joint according to the limit speed.

In combination with any one of the embodiments of the present disclosure, the at least one joint position of the robotic arm includes an upper boundary position of the robotic arm joint, a lower boundary position of the robotic arm joint, and a midpoint position of the robotic arm joint.

In combination with any one of the embodiments of the present disclosure, the speed control amount of the end of the mechanical arm characterizes the moving speed of the end of the mechanical arm in the current control period;

The speed control amount of the mechanical arm joint characterizes the moving speed of the mechanical arm joint in the current control period;

The position control amount of the mechanical arm joint indicates the movement position of the mechanical arm joint in the current control period.

According to a third aspect of embodiments of the present disclosure, there is provided a mechanical arm, comprising:

A memory for storing the processor-executable instructions;

a processor configured to execute executable instructions in the memory to implement the steps of the method of any of the embodiments of the first aspect described above.

According to a fourth aspect of embodiments of the present disclosure, there is provided an electronic device comprising a robotic arm, a memory for storing processor-executable instructions; a processor configured to execute executable instructions in the memory to implement the steps of the method of any of the embodiments of the first aspect described above. Optionally, the electronic device comprises a robot.

According to a fifth aspect of the disclosed embodiments, there is provided a computer readable storage medium having stored thereon a computer program which when executed by a processor performs the steps of the method according to any of the embodiments of the first aspect described above.

The technical scheme provided by the embodiment of the disclosure can comprise the following beneficial effects:

And determining the speed control quantity of the tail end of the mechanical arm through the relative position relation between the current position of the tail end of the mechanical arm and the expected position, the expected speed and the singular position weight, and obtaining the relevant control parameters of the joint of the mechanical arm by inverse solution according to the speed control quantity. The mechanical arm can obtain a determined joint control parameter in each control period, gradually converges in a plurality of control periods, so that calculation time consumption in a single control period is reduced, in addition, negative influences of the singular position of the mechanical arm on solving failure and the like caused by the inverse solution process are reduced through the singular position weight, and reliability of an inverse solution calculation result is improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure.

FIG. 1 is a schematic illustration of a robotic arm according to an exemplary embodiment of the disclosure;

FIG. 2 is a flowchart of a method of controlling a robotic arm according to an exemplary embodiment of the disclosure;

FIG. 3 is a schematic diagram of a robotic arm control device according to an exemplary embodiment of the disclosure;

fig. 4 is a block diagram of a robotic arm apparatus according to an exemplary embodiment of the disclosure.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples are not representative of all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present disclosure as detailed in the accompanying claims.

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

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

The current mechanical arm control method is mainly based on inverse solution of the input mechanical arm tail end control parameters so as to obtain the control parameters of the mechanical arm joints. Exemplary, fig. 1 is a schematic illustration of a robotic arm shown in the present disclosure. In fig. 1, for example, a four-degree-of-freedom serial mechanical arm is taken, after the expected position and the expected speed of the tail end of the mechanical arm are obtained, when the mechanical arm reaches the expected position at the expected speed by a numerical inversion method, joint angles and joint speeds respectively required by joints J1-J4 are calculated, and then a joint control instruction is issued to the mechanical arm for execution. However, in the numerical inversion method of the mechanical arm, since a plurality of inverse solution calculations are required in a single control cycle, the calculation is time-consuming, and when the mechanical arm approaches the odd-ectopic type, a maximum value is generated, resulting in failure of the inverse solution.

Accordingly, the present disclosure provides a method for controlling a mechanical arm, which at least solves the problems of the related art.

Fig. 2 illustrates a flow chart of a method for controlling a robotic arm according to an exemplary embodiment of the disclosure.

In step S101, a desired position of the arm tip and a desired speed of the arm tip when the arm tip is at the desired position are acquired.

The desired position characterizes a target position of the manipulator end in a Cartesian space, and the desired velocity characterizes a velocity value of the manipulator end at the time of reaching the desired position. The desired position and the desired speed may be determined by a control module input to the mechanical arm by a user, or may be determined according to a current actual working requirement of the mechanical arm, which is not limited in the disclosure.

In step S102, a speed control amount of the tail end of the mechanical arm is determined according to a relative positional relationship between the current position of the tail end of the mechanical arm and a desired position, the desired speed and a singular position weight, wherein the singular position weight is related to the current joint position type of the mechanical arm.

The current position of the tail end of the mechanical arm represents the Cartesian space position of the tail end of the mechanical arm at the current moment, and can be determined according to a position sensor of the mechanical arm. And the relative position relation between the current position of the tail end of the mechanical arm and the expected position represents the distance difference between the current position of the tail end of the mechanical arm and the expected position. The singular position weight is used for reducing jump interference caused by the singular position to the inverse solution process of the mechanical arm, and can be determined according to the current joint position type of the mechanical arm. The speed control of the arm tip characterizes a movement speed required for the arm tip in the current control cycle in order to reach the desired position at the desired speed.

In one example, the speed control amount of the robot arm tip may be determined according to equation (1):

v_c＝v_d+ρ*k_p*x_err (1)

In equation (1), v _c represents the velocity control quantity at the end of the mechanical arm, v _d represents the desired velocity, and ρ represents the singular position weight.

X _err represents the relative positional relationship of the current position x _a of the end of the mechanical arm and the desired position x _d, as shown in formula (2):

x_err＝x_d-x_a (2)

Wherein x _a can be specifically characterized as the position of the end of the mechanical arm at the start time of the current control cycle, and updated in each control cycle. So that the speed control quantity of the tail end of the mechanical arm is updated once in each control period, and finally the expected position is reached.

Optionally, k _p represents a preset control gain of the position of the mechanical arm, which is a gain coefficient of x _err, and x _err gradually converges to 0 in a plurality of control periods during the process of gradually moving the mechanical arm to the desired position, and the convergence process can be accelerated or slowed down through k _p.

The singular position weights can be determined according to the current joint position type of the mechanical arm. Under the condition that the mechanical arm is in an odd-abnormal type, the inverse solution of the mechanical arm joint does not exist or a jump extremum is easy to occur, so that the inverse solution calculation result of the mechanical arm can be influenced. The singular bit type comprises a boundary odd bit type and an internal odd bit type, and the boundary odd bit type only appears when the mechanical arm is at a working boundary and can be avoided by restraining the working space of the mechanical arm. The internal odd-type position appears at the moment that the joint axes of the mechanical arm are collinear, so that the operability of the mechanical arm is reduced, and the movable area of the mechanical arm is reduced. Therefore, the negative influence of the singular position of the mechanical arm on solving failure and the like caused by the inverse solving process can be reduced through the singular position weight.

In one example, the singular position weight may be determined from a comparison of a singular value of the robotic arm at a current position type and a singular value of the robotic arm at a singular position type time, as shown in equation (3):

The method comprises the steps of representing the minimum singular value of a mechanical arm in a current joint position type, representing the minimum singular value of the current mechanical arm in all odd abnormal positions by epsilon _min, representing the maximum singular value of the current mechanical arm in all odd abnormal positions by epsilon _max, and determining the singular value according to a jacobian matrix representing the mapping relation between the joint position type of the mechanical arm and the speed control quantity of the tail end of the mechanical arm and the speed control quantity of the joint of the mechanical arm.

Specifically, when the minimum singular value of the current joint position type of the mechanical arm is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, namely, E is less than or equal to E _min, the current mechanical arm is characterized as being in the odd position type, and the mechanical arm can be enabled to move according to the size and the direction of the expected speed by controlling the singular position weight to be zero, so that the influence of the odd position type on the inverse solution process of the mechanical arm is reduced to the greatest extent.

In case the minimum singular value of the manipulator in the current joint position is larger than the minimum singular value of the manipulator in the singular position and smaller than or equal to the maximum singular value of the manipulator in the singular position, i.e. e _min<∈≤∈_max, it is characterized that the current manipulator is approaching the singular position, by controlling the singular position weight and the singular value of the current joint position to be in a positive correlation, e.g. by making the singular position weightIn the process that the mechanical arm approaches to the singular position, the weight of the singular position is continuously reduced, so that the influence of the odd position on the inverse solution process of the mechanical arm is reduced.

And under the condition that the minimum singular value of the current joint position type of the mechanical arm is larger than the maximum singular value of the mechanical arm in the singular position type, namely epsilon _max < epsilon >, the current mechanical arm is far away from the singular position type, the terminal speed control quantity of the mechanical arm in the current control period can be determined through controlling the singular position weight to be 1 and through the expected speed and the relative position relation between the expected position and the current position.

Preferably, in order to prevent the relative positional relationship from being too large, a sudden change is generated in the inverse solution process, and the relative positional relationship may be corrected when the relative positional relationship exceeds a preset positional threshold, so that the relative positional relationship is within the preset positional threshold, as shown in formula (4):

In equation (4), x _err1 represents the corrected relative positional relationship, and v _max represents the preset positional threshold, which may be determined according to the maximum distance that the robot arm tip can move at the fastest speed in a single control cycle.

In step S103, a speed control amount of the arm joint is determined according to the speed control amount of the arm end.

After the speed control quantity of the tail end of the mechanical arm is obtained, the speed control quantity of the mechanical arm joint in the current control period can be calculated through the mapping relation between the mechanical arm joint speed and the tail end speed.

Illustratively, the speed control amount of the robot arm joint may be determined by the formula (5):

dq_c＝J⁺*v_c (5)

In the formula (5), dq _c represents the speed control quantity of the mechanical arm joint, J represents the jacobian matrix, J ⁺ represents the inverse solution operation form of the jacobian matrix, and v _c is the mechanical arm tail end speed control quantity obtained in the above steps according to the jacobian matrix J and the matrix damping value.

The matrix damping value is used for scaling the mapping relation of J ⁺ so as to avoid the influence of odd-abnormal position on the inverse solution process of the mechanical arm.

For example, when the minimum singular value of the current joint position type of the mechanical arm is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, that is, e is less than or equal to e _min, the current mechanical arm is characterized as being in the odd position type, and the matrix damping value and the singular value of the current joint position type can be controlled to be in a negative correlation relationship, as shown in a formula (6):

in the formula (6) of the present invention, And the matrix damping value is characterized, jump extremum is easy to appear in the inverse solution process of the mechanical arm under the condition that the mechanical arm is in an odd-dislocation type, and the stability of the inverse solution process of the mechanical arm can be increased by gradually amplifying the matrix damping value in the process that the minimum singular value of the mechanical arm in the singular-dislocation type is reduced, so that the influence of the odd-dislocation type on the inverse solution process of the mechanical arm is reduced.

When the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type, namely, epsilon > -epsilon _min, the mechanical arm is characterized by being not in an odd-dislocation type, and the matrix damping value can be controlled to be 0, as shown in a formula (7):

J⁺＝J^T*(J*J^T)^-1 (7)

In the formula (7), since the mechanical arm is not in an odd-type, the jacobian matrix suitable for the inverse solution process can be obtained without scaling adjustment of the jacobian matrix.

In step S104, the position control amount of the robot arm joint is determined from the current joint position of the robot arm and the speed control amount of the robot arm joint.

The current joint position of the mechanical arm can be determined through a position sensor of the mechanical arm, the position state of the mechanical arm joint in the current control period is represented, the position control quantity of the mechanical arm joint is represented, and the movement position required by the mechanical arm joint in the current control period is represented so that the tail end of the mechanical arm reaches the expected position at the expected speed.

In one example, the position control amount of the robot arm joint may be determined by the formula (8):

q_cmd＝q_a+dq_c*δt (8)

In formula (8), q _cmd represents a position control amount of a robot arm joint, q _a represents a current joint position of the robot arm, dq _c represents a speed control amount of the robot arm joint, and σt represents a preset robot arm control period (for example, 0.5ms or 0.8 ms).

Preferably, in order to ensure that the position control amount of the mechanical arm joint conforms to the actual joint position limit, the limit speed of the mechanical arm joint may be predetermined and the speed control amount of the mechanical arm joint may be updated before the position control amount of the mechanical arm joint is determined.

Specifically, the limiting speed of the mechanical arm joint can be determined according to the jacobian matrix, the degree of freedom of the mechanical arm and at least one joint position of the mechanical arm, and the speed control quantity of the mechanical arm joint is updated according to the limiting speed, as shown in formula (9) and formula (10):

dq_cmd＝dq_c+dq_b (10)

In the formula (9), dq _b represents the limiting speed of the mechanical arm joint, N (q) represents the zero-space matrix of the jacobian matrix J, k _b represents the preset limiting adjustment parameter of the mechanical arm joint, N represents the degree of freedom of the mechanical arm, q _max represents the upper boundary position of the mechanical arm joint, q _min represents the lower boundary position of the mechanical arm joint, and q _mid represents the midpoint position of the mechanical arm joint.

In the formula (10), dq _cmd represents the updated speed control quantity of the mechanical arm joint, and the speed control quantity of the mechanical arm joint is corrected through limiting speed, so that the position control quantity of the mechanical arm joint accords with the actual joint position limit, the joint movement mode of the mechanical arm is ensured to accord with the actual, and the problem of reverse jump easily generated when the joint moves to the boundary position is avoided.

In step S105, the movement of the robot arm is controlled according to the speed control amount and the position control amount of the robot arm joint.

And transmitting the speed control quantity of the mechanical arm joint and the position control quantity of the mechanical arm joint obtained in the steps to a joint controller of the mechanical arm so as to enable the mechanical arm to complete corresponding movement in the current control medium stage. The above process is repeated continuously, so that the mechanical arm is controlled according to the speed control quantity and the position control quantity of the mechanical arm joint in each control period until the tail end of the mechanical arm finally reaches the desired position at the desired speed.

According to the method, in each control period, the speed control quantity of the tail end of the mechanical arm is determined through the relative position relation between the current position and the expected position of the tail end of the mechanical arm, the expected speed and the singular position weight, and relevant control parameters of joints of the mechanical arm in the current control period are obtained through inverse solution according to the speed control quantity. The mechanical arm can obtain a determined joint control parameter in each control period, gradually converges in a plurality of control periods, so that calculation time consumption in a single control period is reduced, in addition, negative influences of the singular position of the mechanical arm on solving failure and the like caused by the inverse solution process are reduced through the singular position weight, and reliability of an inverse solution calculation result is improved.

In an alternative embodiment, before determining the speed control amount of the tail end of the mechanical arm according to the relative position relation between the current position of the tail end of the mechanical arm and the expected position, the expected speed and the singular position weight, the expected position may be pre-corrected to ensure the rationality of the setting of the expected position.

Firstly, according to the maximum length of the mechanical arm and a preset boundary weight, determining the maximum space position which can be reached by the mechanical arm, and correcting the expected position to enable the expected position to be in the maximum space position in response to the expected position exceeding the maximum space position.

The maximum length of the mechanical arm represents the maximum length that the mechanical arm can reach under the condition that each joint is fully unfolded, namely, under the condition that the mechanical arm is straightened, the boundary weight is a shrinkage factor of the maximum length of the mechanical arm, so that the maximum length does not comprise the condition that the mechanical arm is at a singular position, the maximum spatial position that the mechanical arm can reach is a spatial position set formed by the maximum length that the mechanical arm can reach under the condition that the singular position is excluded, and in one example, the maximum spatial position represents a spherical surface formed by a furthest distance position point set that the end of the mechanical arm can reach.

In one example, the correction may be performed by determining the desired position of the arm tip through equation (11).

In formula (11), x _d1 denotes a corrected desired position, x _d denotes a desired position before correction, L _arm denotes a maximum length of the mechanical arm, w _arm denotes a preset boundary weight, and in the case where the desired position exceeds the maximum spatial position, that is, x _d>L_arm*w_arm, the input desired position is corrected so that the desired position is within the maximum spatial position.

And then, acquiring a preset working space position of the mechanical arm, and correcting the expected position to enable the expected position to be in the working space position in response to the expected position exceeding the working space position.

The working space position of the mechanical arm represents a position set which can be reached by the tail end of the mechanical arm in an actual working environment. In the actual working process, the tail end of the mechanical arm cannot normally move smoothly in the maximum space position due to the interference of surrounding objects, and the expected position can be further corrected by the formula (12)

In equation (12), x _d2 denotes a corrected desired position, x _d denotes a desired position before correction, S _boud (x, y, z) denotes a preset working space position of the robot arm, and in the case where the desired position is beyond the working space position, i.e., x _d>S_boud (x, y, z), the input desired position is corrected so that the desired position is within the working space position.

According to the method, the expected position is pre-corrected to ensure the rationality of the setting of the expected position, so that the tail end of the mechanical arm always moves in the maximum space position and the working space position, and the space limit of the mechanical arm is realized.

For the foregoing method embodiments, for simplicity of explanation, the methodologies are shown as a series of acts, but one of ordinary skill in the art will appreciate that the present disclosure is not limited by the order of acts described, as some steps may occur in other orders or concurrently in accordance with the disclosure.

Further, those skilled in the art will also appreciate that the embodiments described in the specification are all alternative embodiments, and that the acts and modules referred to are not necessarily required by the present disclosure.

Corresponding to the embodiment of the application function implementation method, the disclosure also provides an embodiment of the application function implementation device and a corresponding terminal.

A block diagram of a robot arm control device according to an exemplary embodiment of the present disclosure is shown in fig. 3, where the device includes:

the parameter obtaining module 301 is configured to: acquiring a desired position of the tail end of the mechanical arm and a desired speed when the tail end of the mechanical arm is positioned at the desired position;

The end speed determination module 302 is configured to: determining the speed control quantity of the tail end of the mechanical arm according to the relative position relation between the current position of the tail end of the mechanical arm and the expected position, the expected speed and the singular position weight, wherein the singular position weight is related to the current joint position type of the mechanical arm;

the joint velocity determination module 303 is configured to: determining the speed control quantity of the mechanical arm joint according to the speed control quantity of the tail end of the mechanical arm;

the joint position determination module 304 is configured to: determining the position control quantity of the mechanical arm joint according to the current joint position of the mechanical arm and the speed control quantity of the mechanical arm joint;

a robotic arm control module 305 for: and controlling the movement of the mechanical arm according to the speed control quantity and the position control quantity of the mechanical arm joint.

In combination with any one of the embodiments of the present disclosure, before determining the speed control amount of the tail end of the mechanical arm according to the relative positional relationship between the current position and the desired position of the tail end of the mechanical arm, the desired speed and the singular position weight, the apparatus further includes a first limiting module configured to:

determining the maximum space position which can be reached by the mechanical arm according to the maximum length of the mechanical arm and preset boundary weight;

In response to the desired position exceeding the maximum spatial position, the desired position is corrected to bring the desired position within the maximum spatial position.

In combination with any one of the embodiments of the present disclosure, before determining the speed control amount of the tail end of the mechanical arm according to the relative positional relationship between the current position and the desired position of the tail end of the mechanical arm, the desired speed and the singular position weight, the device further includes a second limiting module, configured to:

Acquiring a preset working space position of the mechanical arm;

in response to the desired position exceeding the workspace position, the desired position is corrected to bring the desired position within the workspace position.

In combination with any of the embodiments of the present disclosure, the apparatus further includes a weight determination module for:

responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, wherein the singular position weight is zero;

responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type and smaller than or equal to the maximum singular value of the mechanical arm in the singular position type, wherein the singular position weight and the singular value of the current joint position type are in positive correlation;

Responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is larger than the maximum singular value of the mechanical arm in the singular position type, wherein the singular position weight is one;

The singular values are determined according to a jacobian matrix representing a mapping relation between joint positions of the mechanical arm and speed control quantity of the tail end of the mechanical arm and speed control quantity of joints of the mechanical arm.

In combination with any one of the embodiments of the present disclosure, before determining the speed control amount of the robot arm end according to the relative positional relationship between the current position of the robot arm end and the desired position, the desired speed and the singular position weight, the apparatus further includes an error correction module configured to:

and correcting the relative position relation to enable the relative position relation to be within the preset position threshold value in response to the relative position relation exceeding the preset position threshold value.

In combination with any one of the embodiments of the present disclosure, when the joint speed determining module determines a speed control amount of a robot joint according to a speed control amount of a robot end, the joint speed determining module is specifically configured to:

Determining the speed control quantity of the mechanical arm joint according to the speed control quantity of the tail end of the mechanical arm based on the jacobian matrix and the matrix damping value;

The method comprises the steps that in response to the fact that the minimum singular value of the mechanical arm in the current joint position type is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, the matrix damping value and the singular value of the current joint position type are in a negative correlation;

the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type, and the matrix damping value is zero;

The singular values are determined according to a jacobian matrix representing a mapping relationship between joint positions of the mechanical arm and speed control amounts of the tail end of the mechanical arm and the joints of the mechanical arm.

In combination with any one of the embodiments of the present disclosure, before determining the position control amount of the mechanical arm joint according to the current joint position of the mechanical arm, the apparatus further includes a third limiting module configured to:

Determining the limiting speed of a joint of the mechanical arm according to a jacobian matrix, the degree of freedom of the mechanical arm and at least one joint position of the mechanical arm, wherein the jacobian matrix represents a mapping relation between the speed control quantity of the tail end of the mechanical arm and the speed control quantity of the joint of the mechanical arm;

and updating the speed control quantity of the mechanical arm joint according to the limit speed.

In combination with any one of the embodiments of the present disclosure, the at least one joint position of the robotic arm includes an upper boundary position of the robotic arm joint, a lower boundary position of the robotic arm joint, and a midpoint position of the robotic arm joint.

In combination with any one of the embodiments of the present disclosure, the speed control amount of the end of the mechanical arm characterizes the moving speed of the end of the mechanical arm in the current control period;

The speed control amount of the mechanical arm joint characterizes the moving speed of the mechanical arm joint in the current control period;

The position control amount of the mechanical arm joint indicates the movement position of the mechanical arm joint in the current control period.

For the device embodiments, reference is made to the description of the method embodiments for the relevant points, since they essentially correspond to the method embodiments. The apparatus embodiments described above are merely illustrative, wherein the elements described above as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the objectives of the disclosed solution. Those of ordinary skill in the art will understand and implement the present invention without undue burden.

The embodiments of the motion control apparatus of the present specification may be applied to a computer device of a robot arm, such as a server or a terminal device. The apparatus embodiments may be implemented by software, or may be implemented by hardware or a combination of hardware and software. Taking software implementation as an example, the device in a logic sense is formed by reading corresponding computer program instructions in a nonvolatile memory into a memory through a processor of motion control where the device is located.

In terms of hardware, as shown in fig. 4, a hardware structure diagram of a mechanical arm where the motion control device according to the embodiment of the present disclosure is shown, except for the processor 410, the memory 430, the network interface 420, and the nonvolatile memory 440 shown in fig. 4, a server or an electronic device where the embodiment is located may include other hardware according to the actual function of the computer device, which is not described herein.

Another embodiment of the present disclosure also provides a robotic arm. The robotic arm includes a memory for storing processor-executable instructions; a processor configured to execute executable instructions in the memory to implement the steps of the robotic arm control method provided in the present disclosure.

Another embodiment of the present disclosure also provides an electronic device. Optionally, the electronic device comprises a robot comprising a robotic arm. The robot further comprises a memory for storing processor executable instructions and a processor configured to execute the executable instructions in the memory to implement the steps of the robotic arm control method provided in the present disclosure.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This application is intended to cover any adaptations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It is to be understood that the present disclosure is not limited to the precise arrangements and instrumentalities shown in the drawings, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims (21)

1. A method of controlling a robotic arm, the method comprising:

acquiring a desired position of the tail end of the mechanical arm and a desired speed when the tail end of the mechanical arm is positioned at the desired position;

Determining the speed control quantity of the tail end of the mechanical arm according to the relative position relation between the current position of the tail end of the mechanical arm and the expected position, the expected speed and the singular position weight, wherein the singular position weight is related to the current joint position type of the mechanical arm;

Determining the speed control quantity of the mechanical arm joint according to the speed control quantity of the tail end of the mechanical arm;

determining the position control quantity of the mechanical arm joint according to the current joint position of the mechanical arm and the speed control quantity of the mechanical arm joint;

and controlling the movement of the mechanical arm according to the speed control quantity and the position control quantity of the mechanical arm joint.

2. The method of claim 1, wherein prior to determining the velocity control quantity for the robot arm tip based on the relative positional relationship of the current position of the robot arm tip to the desired position, the desired velocity, and the singular position weights, the method further comprises:

determining the maximum space position which can be reached by the mechanical arm according to the maximum length of the mechanical arm and preset boundary weight;

In response to the desired position exceeding the maximum spatial position, the desired position is corrected to bring the desired position within the maximum spatial position.

3. The method according to claim 1 or 2, wherein before determining the velocity control amount of the arm tip based on the relative positional relationship of the arm tip current position and the desired position, the desired velocity, and the singular position weight, the method further comprises:

Acquiring a preset working space position of the mechanical arm;

in response to the desired position exceeding the workspace position, the desired position is corrected to bring the desired position within the workspace position.

4. The method according to claim 1, wherein the method further comprises:

responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, wherein the singular position weight is zero;

responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type and smaller than or equal to the maximum singular value of the mechanical arm in the singular position type, wherein the singular position weight and the singular value of the current joint position type are in positive correlation;

Responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is larger than the maximum singular value of the mechanical arm in the singular position type, wherein the singular position weight is one;

The singular values are determined according to a jacobian matrix representing a mapping relation between joint positions of the mechanical arm and speed control quantity of the tail end of the mechanical arm and speed control quantity of joints of the mechanical arm.

5. The method of claim 1, wherein prior to determining the velocity control quantity for the robot arm tip based on the relative positional relationship of the current position of the robot arm tip to the desired position, the desired velocity, and the singular position weights, the method further comprises:

and correcting the relative position relation to enable the relative position relation to be within the preset position threshold value in response to the relative position relation exceeding the preset position threshold value.

6. The method of claim 1, wherein determining the velocity control amount of the robot joint based on the velocity control amount of the robot tip comprises:

Determining the speed control quantity of the mechanical arm joint according to the speed control quantity of the tail end of the mechanical arm based on the jacobian matrix and the matrix damping value;

The method comprises the steps that in response to the fact that the minimum singular value of the mechanical arm in the current joint position type is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, the matrix damping value and the singular value of the current joint position type are in a negative correlation;

the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type, and the matrix damping value is zero;

The singular values are determined according to a jacobian matrix representing a mapping relationship between joint positions of the mechanical arm and speed control amounts of the tail end of the mechanical arm and the joints of the mechanical arm.

7. The method of claim 1, wherein before determining the position control amount of the robot joint based on the current joint position of the robot, the method further comprises:

Determining the limiting speed of a joint of the mechanical arm according to a jacobian matrix, the degree of freedom of the mechanical arm and at least one joint position of the mechanical arm, wherein the jacobian matrix represents a mapping relation between the speed control quantity of the tail end of the mechanical arm and the speed control quantity of the joint of the mechanical arm;

and updating the speed control quantity of the mechanical arm joint according to the limit speed.

8. The method of claim 1, wherein the at least one joint position of the robotic arm comprises an upper boundary position of a robotic arm joint, a lower boundary position of a robotic arm joint, and a midpoint position of a robotic arm joint.

9. The method of claim 1, wherein the speed control amount of the robot arm tip characterizes a movement speed of the robot arm tip in a current control cycle;

The speed control amount of the mechanical arm joint characterizes the moving speed of the mechanical arm joint in the current control period;

The position control amount of the mechanical arm joint indicates the movement position of the mechanical arm joint in the current control period.

10. A robotic arm control device, the device comprising:

The parameter acquisition module is used for: acquiring a desired position of the tail end of the mechanical arm and a desired speed when the tail end of the mechanical arm is positioned at the desired position;

An end speed determination module for: determining the speed control quantity of the tail end of the mechanical arm according to the relative position relation between the current position of the tail end of the mechanical arm and the expected position, the expected speed and the singular position weight, wherein the singular position weight is related to the current joint position type of the mechanical arm;

A joint velocity determination module for: determining the speed control quantity of the mechanical arm joint according to the speed control quantity of the tail end of the mechanical arm;

A joint position determination module for: determining the position control quantity of the mechanical arm joint according to the current joint position of the mechanical arm and the speed control quantity of the mechanical arm joint;

The mechanical arm control module is used for: and controlling the movement of the mechanical arm according to the speed control quantity and the position control quantity of the mechanical arm joint.

11. The apparatus of claim 10, wherein before determining the velocity control amount of the robot arm tip based on the relative positional relationship of the current position of the robot arm tip and the desired position, the desired velocity, and the singular position weight, the apparatus further comprises a first limiting module configured to:

determining the maximum space position which can be reached by the mechanical arm according to the maximum length of the mechanical arm and preset boundary weight;

In response to the desired position exceeding the maximum spatial position, the desired position is corrected to bring the desired position within the maximum spatial position.

12. The apparatus according to claim 10 or 11, wherein before determining the speed control amount of the robot arm tip based on the relative positional relationship of the robot arm tip current position and the desired position, the desired speed and the singular position weight, the apparatus further comprises a second limiting module for:

Acquiring a preset working space position of the mechanical arm;

in response to the desired position exceeding the workspace position, the desired position is corrected to bring the desired position within the workspace position.

13. The apparatus of claim 10, further comprising a weight determination module to:

responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, wherein the singular position weight is zero;

responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type and smaller than or equal to the maximum singular value of the mechanical arm in the singular position type, wherein the singular position weight and the singular value of the current joint position type are in positive correlation;

Responding to the fact that the minimum singular value of the mechanical arm in the current joint position type is larger than the maximum singular value of the mechanical arm in the singular position type, wherein the singular position weight is one;

The singular values are determined according to a jacobian matrix representing a mapping relation between joint positions of the mechanical arm and speed control quantity of the tail end of the mechanical arm and speed control quantity of joints of the mechanical arm.

14. The apparatus of claim 10, wherein prior to determining the velocity control quantity of the robot arm tip based on the relative positional relationship of the robot arm tip current position to the desired position, the desired velocity, and the singular position weight, the apparatus further comprises an error correction module for:

and correcting the relative position relation to enable the relative position relation to be within the preset position threshold value in response to the relative position relation exceeding the preset position threshold value.

15. The device according to claim 10, wherein when the joint speed determining module determines the speed control amount of the robot joint according to the speed control amount of the robot end, the device is specifically configured to:

Determining the speed control quantity of the mechanical arm joint according to the speed control quantity of the tail end of the mechanical arm based on the jacobian matrix and the matrix damping value;

The method comprises the steps that in response to the fact that the minimum singular value of the mechanical arm in the current joint position type is smaller than or equal to the minimum singular value of the mechanical arm in the singular position type, the matrix damping value and the singular value of the current joint position type are in a negative correlation;

the minimum singular value of the mechanical arm in the current joint position type is larger than the minimum singular value of the mechanical arm in the singular position type, and the matrix damping value is zero;

The singular values are determined according to a jacobian matrix representing a mapping relationship between joint positions of the mechanical arm and speed control amounts of the tail end of the mechanical arm and the joints of the mechanical arm.

16. The apparatus of claim 10, wherein before determining the position control amount of the robot joint based on the current joint position of the robot, the speed control amount of the robot joint, the apparatus further comprises a third limit module for:

Determining the limiting speed of a joint of the mechanical arm according to a jacobian matrix, the degree of freedom of the mechanical arm and at least one joint position of the mechanical arm, wherein the jacobian matrix represents a mapping relation between the speed control quantity of the tail end of the mechanical arm and the speed control quantity of the joint of the mechanical arm;

and updating the speed control quantity of the mechanical arm joint according to the limit speed.

17. The apparatus of claim 10, wherein the at least one joint position of the robotic arm comprises an upper boundary position of a robotic arm joint, a lower boundary position of a robotic arm joint, and a midpoint position of a robotic arm joint.

18. The apparatus of claim 10, wherein the speed control amount of the robot arm tip characterizes a moving speed of the robot arm tip in a current control cycle;

The speed control amount of the mechanical arm joint characterizes the moving speed of the mechanical arm joint in the current control period;

The position control amount of the mechanical arm joint indicates the movement position of the mechanical arm joint in the current control period.

19. A robotic arm, the robotic arm comprising:

A memory for storing processor-executable instructions;

A processor configured to execute executable instructions in the memory to implement the steps of the method of any one of claims 1 to 9.

20. An electronic device includes a robotic arm;

A memory for storing processor-executable instructions;

A processor configured to execute executable instructions in the memory to implement the steps of the method of any one of claims 1 to 9.

21. A computer readable storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, implements the steps of the method of any of claims 1 to 9.