JP-2026514218-A - Calibration method for articulated robots, computer device, and readable storage medium

JP2026514218AJP 2026514218 AJP2026514218 AJP 2026514218AJP-2026514218-A

Abstract

This disclosure relates to a calibration method for an articulated robot, a computer device, and a non-temporary computer-readable storage medium. The method includes acquiring desired trajectory information relating to a desired trajectory of an end effector (S110), acquiring load information relating to loads on the articulated robot, including gravitational loads, inertial loads, and external loads (S120), acquiring joint position data indicating the joint positions of the articulated robot based on the desired trajectory information (S130), acquiring tip position change data indicating changes in the tip position of the end effector based on the joint position data and load information (S140), and compensating for position errors of the end effector according to a predetermined compensation strategy based on the tip position change data (S150). [Selection Diagram] Figure 4

Inventors

ディンホウシュ
ジアンハオ

Assignees

シャンハイ・フレクシブ・ロボティクス・テクノロジー・カンパニー・リミテッド
フレクシブ・リミテッド

Dates

Publication Date: 20260507
Application Date: 20230420

Claims (20)

A calibration method for an articulated robot having an end effector, The aforementioned method, To obtain desired trajectory information regarding the desired trajectory of the end effector, To acquire load information regarding the loads, including gravity load, inertial load, and external load, that the aforementioned articulated robot experiences, Based on the aforementioned desired trajectory information, joint position data indicating the joint positions of the articulated robot is acquired, Based on the joint position data and the load information, tip position change data indicating the change in the tip position of the end effector is acquired, A method comprising compensating for the position error of the end effector according to a predetermined compensation strategy based on the tip position change data.
Based on the aforementioned joint position data and load information, obtaining tip position change data that shows the change in the tip position of the end effector is: Based on the deformation coefficient of each link of the articulated robot under a unit load, link deformation data is calculated that shows the deformation of all links of the articulated robot under the load. Based on the deformation coefficient of each joint of the articulated robot under a unit load, joint deformation data showing the deformation of all joints of the articulated robot under the load is calculated, The method according to claim 1, characterized in that it includes obtaining tip position change data based on the joint position data, the link deformation data and the joint deformation data.
Based on the aforementioned joint position data, link deformation data, and joint deformation data, the acquisition of the tip position change data is: The method according to the previous version, characterized in that it includes acquiring tip position change data based on the link deformation data, the joint deformation data, the joint position data, and the forward kinematic model from the base to the end flange of the articulated robot.
The above method further, This includes receiving user input and setting the predetermined compensation strategy as the first compensation strategy, If the predetermined compensation strategy is set as the first compensation strategy, then compensating the position error of the end effector according to the predetermined compensation strategy based on the tip position change data is: The method according to claim 1, characterized in that it includes determining joint position change data based on the tip position change data and controlling the movement of the articulated robot using the joint position change data.
The aforementioned joint position change data includes updated joint position data. Determining joint position change data based on the aforementioned tip position change data, and controlling the movement of the multi-joint robot using the aforementioned joint position change data, The difference between the aforementioned desired trajectory information and the aforementioned tip position change data is calculated to obtain updated trajectory data. The updated trajectory data is processed based on the inverse kinematics model of the articulated robot to obtain the updated joint position data. The method according to 4, characterized in that it includes controlling the movement of the articulated robot using the updated joint position data.
The joint position data includes a first joint angle, and the joint position change data includes joint angle error data. Determining joint position change data based on the aforementioned tip position change data, and controlling the movement of the multi-joint robot using the aforementioned joint position change data, Based on the aforementioned tip position change data and the Jacobian matrix of the current posture of the articulated robot, the joint angle error data is acquired. The method according to claim 4, characterized in that it includes compensating the first joint angle using the joint angle error data and controlling the movement of the articulated robot according to the compensated joint angle.
The aforementioned joint position data includes a second joint angle, Based on the aforementioned desired trajectory information, acquiring joint position data indicating the joint positions of the articulated robot is: The method according to claim 1, characterized in that it includes processing the desired trajectory information based on the Jacobian matrix of the current posture of the articulated robot to obtain the second joint angle.
The above method further, This includes receiving user input and setting the predetermined compensation strategy as a second compensation strategy, If the predetermined compensation strategy is set as the second compensation strategy, then compensating for the position error of the end effector according to the predetermined compensation strategy based on the tip position change data is: The difference between the desired trajectory information and the tip position change data is calculated to obtain the planned trajectory data. The method according to 7, characterized in that it includes compensating for the tip position of the end effector using the planned trajectory data.
The aforementioned joint position data includes a third joint angle, Based on the aforementioned desired trajectory information, acquiring joint position data indicating the joint positions of the articulated robot is: Based on the aforementioned desired trajectory information, a joint angle optimization problem is constructed using the joint angles of the assumed modified trajectory executed by the end effector as the optimization target quantity. Based on assumed corrected trajectory data, the joint angles under the corrected trajectory, and the Jacobian matrix of the current posture of the articulated robot, the constraints on the joint angle optimization problem are determined. The method according to claim 1, characterized by comprising: converging for optimization with the goal of minimizing the difference between the assumed corrected trajectory data and the target trajectory data, and obtaining the third joint angle.
The above method further, This includes receiving user input and setting the predetermined compensation strategy as the third compensation strategy, If the predetermined compensation strategy is set as the third compensation strategy, then compensating for the position error of the end effector according to the predetermined compensation strategy based on the tip position change data is: The difference between the desired trajectory information and the tip position change data is calculated to obtain the target trajectory data. The method according to 9, characterized in that it includes compensating for the tip position of the end effector using the target trajectory data.
A computer device including a processor and memory for storing instructions that the processor can execute, wherein when an instruction that the processor can execute is executed by the processor, the processor... To obtain desired trajectory information regarding the desired trajectory of the end effector of a multi-joint robot, To acquire load information regarding the loads, including gravity load, inertial load, and external load, that the aforementioned articulated robot experiences, Based on the aforementioned desired trajectory information, joint position data indicating the joint positions of the articulated robot is acquired, Based on the joint position data and the load information, tip position change data indicating the change in the tip position of the end effector is acquired, A computer device that performs the following: compensating for the position error of the end effector according to a predetermined compensation strategy based on the tip position change data.
Based on the aforementioned joint position data and load information, obtaining tip position change data that shows the change in the tip position of the end effector is: Based on the deformation coefficient of each link of the articulated robot under a unit load, link deformation data is calculated that shows the deformation of all links of the articulated robot under the load. Based on the deformation coefficient of each joint of the articulated robot under a unit load, joint deformation data showing the deformation of all joints of the articulated robot under the load is calculated, The computer device according to claim 11, characterized in that it includes acquiring tip position change data based on the joint position data, the link deformation data and the joint deformation data.
Based on the aforementioned joint position data, link deformation data, and joint deformation data, the acquisition of the tip position change data is: The computer device according to claim 12, characterized in that it includes acquiring tip position change data based on the link deformation data, the joint deformation data, the joint position data, and the forward kinematic model from the base to the end flange of the articulated robot.
When an instruction executable by the processor is executed by the processor, the processor is instructed to receive user input and set the predetermined compensation strategy as the first compensation strategy. If the predetermined compensation strategy is set as the first compensation strategy, then compensating the position error of the end effector according to the predetermined compensation strategy based on the tip position change data is: The computer device according to claim 11, characterized in that it includes determining joint position change data based on the tip position change data and controlling the movement of the articulated robot using the joint position change data.
The joint position change data includes updated joint position data, the joint position change data is determined based on the tip position change data, and the movement of the multi-joint robot is controlled using the joint position change data. The difference between the aforementioned desired trajectory information and the aforementioned tip position change data is calculated to obtain updated trajectory data. The updated trajectory data is processed based on the inverse kinematics model of the aforementioned articulated robot to obtain updated joint position data. The computer device according to claim 14, further comprising controlling the movement of the articulated robot using the updated joint position data.
The joint position data includes a first joint angle, the joint position change data includes joint angle error data, the joint position change data is determined based on the tip position change data, and the movement of the multi-joint robot is controlled using the joint position change data. Based on the aforementioned tip position change data and the Jacobian matrix of the current posture of the articulated robot, the joint angle error data is acquired. The computer device according to claim 14, characterized by comprising compensating the first joint angle using the joint angle error data and controlling the motion of the articulated robot according to the compensated joint angle.
The aforementioned joint position data includes a second joint angle, and based on the desired trajectory information, joint position data indicating the joint position of the multi-joint robot is obtained. The computer device according to claim 11, characterized in that it includes processing the desired trajectory information based on the Jacobian matrix of the current posture of the articulated robot to obtain the second joint angle.
When an instruction executable by the processor is executed by the processor, the processor is instructed to receive user input and set the predetermined compensation strategy as the second compensation strategy. If the predetermined compensation strategy is set as the second compensation strategy, then compensating for the position error of the end effector according to the predetermined compensation strategy based on the tip position change data is: The difference between the desired trajectory information and the tip position change data is calculated to obtain the planned trajectory data. The computer device according to claim 17, further comprising compensating for the tip position of the end effector using the planned trajectory data.
The aforementioned joint position data includes a third joint angle, and based on the desired trajectory information, joint position data indicating the joint position of the multi-joint robot is obtained. Based on the aforementioned desired trajectory information, a joint angle optimization problem is constructed using the joint angles of the assumed modified trajectory executed by the end effector as the optimization target quantity. Based on assumed corrected trajectory data, the joint angles under the corrected trajectory, and the Jacobian matrix of the current posture of the articulated robot, the constraints on the joint angle optimization problem are determined. The computer device according to claim 11, comprising: converging for optimization with the goal of minimizing the difference between assumed corrected trajectory data and target trajectory data, and obtaining the third joint angle.
When an instruction executable by the processor is executed by the processor, the processor is instructed to receive user input and set the predetermined compensation strategy as the third compensation strategy. If the predetermined compensation strategy is set as the third compensation strategy, then compensating for the position error of the end effector according to the predetermined compensation strategy based on the tip position change data is: The difference between the desired trajectory information and the tip position change data is calculated to obtain the target trajectory data. The computer device according to claim 19, characterized by comprising compensating for the tip position of the end effector using the target trajectory data.

Description

This disclosure relates to the field of robotics, and more particularly to a calibration method for articulated robots, a computer device, and a readable storage medium. Industrial robots possess a large workspace and degrees of freedom, and by extending different actuators to their end-effectors, they can perform a variety of production tasks. Currently, many industrial robots employ a series chain structure with low joint rigidity, causing significant displacement of the robot's end-effector due to the force or torque acting on it, resulting in reduced positioning accuracy under external loads. Positioning accuracy is a crucial characteristic of robot arms in advanced manufacturing or industrial applications, such as visual servo-assisted picking and placement, and collaborative processes between humans and robots. Improving robot positioning accuracy significantly expands the applications of robot arms. Typically, robot positioning errors include primarily geometric and non-geometric errors. Geometric errors are dimensional errors caused during processes such as the manufacturing and assembly of robot components, while non-geometric errors are mainly caused by factors such as the robot's own rigidity, controller bandwidth, ambient temperature, and external loads. Conventional techniques rely on kinematic levels for calibrating most industrial robots, but they struggle to compensate for robot deformation caused by external loads or the robot's own gravity. Identifying the stiffness of the robot's stiffness model can reduce errors caused by loads. However, due to the complexity of load conditions in various robot postures, accurate calibration within the robot's workspace is difficult, and the problem of low end-effector positioning accuracy remains. This is a schematic diagram of a multi-joint robot according to one embodiment of the present disclosure.This is a block diagram showing the configuration of a control unit for a multi-joint robot according to one embodiment of the present disclosure.This is a schematic diagram of a multi-joint robot system according to one embodiment of the present disclosure.This is a flowchart of a calibration method for an articulated robot according to one embodiment of the present disclosure.This diagram shows a schematic representation of the output surface of a single link from the pre-deformation coordinate system E to the post-deformation coordinate system F according to one embodiment of the present disclosure. To facilitate understanding of this disclosure, it will be described more comprehensively with reference to the relevant drawings. The drawings illustrate embodiments of this disclosure. However, this disclosure may be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to make the disclosure more complete and thorough. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as that ordinarily understood by those skilled in the art of this disclosure. The terms used in this disclosure are for illustrative purposes only and are not intended to limit the disclosure. To further clarify the purpose, technical solutions, and advantages of this disclosure, the disclosure will be described in more detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are used solely for illustrative purposes and not to limit the disclosure. Figure 1 shows an exemplary articulated robot (hereinafter also referred to as the robot) applicable to embodiments of the present disclosure. The robot may be an industrial robot or any other type of robot, such as a humanoid robot. As shown in Figure 1, the robot may include a base 10, a plurality of links 11, and an end effector 12. The joints of each link 11 are also referred to as joints 110, with the proximal link connected to the base 10 via a joint, the distal link connected to the end effector 12 via another joint, and two adjacent links also connected via other joints. These joints 110 include pitch joints, roll joints, and other types of rotary joints. Each joint is provided with a corresponding actuator for driving the movement of each joint 110. The end effector 12 can be fitted with an operating tool (not shown) via an end flange 120 to manipulate an object to be manipulated. The operating tool is a variety of tools that can be used to manipulate the object to be manipulated, such as a holding member, used to hold the workpiece to be manipulated. The robot further includes a control unit. Figure 2 shows a block diagram illustrating the configuration of a robot control unit 200 applied to an embodiment of this disclosure. This control unit 200 includes a controller 210, a memory unit 220, a communication unit 230, and an output unit 240. This control unit 200 can be configured to control the robot's posture and the operation of the