A method for calibrating spatial errors of six-axis joint industrial robots based on ballbar

Abstract

A method for calibrating space errors of a six-axis joint industrial robot based on a ballbar relates to a robot. By using high-precision (resolution up to 0.1μm) ballbar and circular grating and other equipment, the error existing in the robot's spatial motion is measured, and the error is compensated into the robot's kinematics model to reduce the robot's motion. deviation. The characteristics of the spatial trajectory used in the designed experiment are that the set trajectory is the bottom profile of the cone with the ballbar as the generatrix, and the apex angle of the cone can be determined according to the angle γ between the ballbar rod and the horizontal plane. During the measurement process, the angle γ between the ballbar member and the horizontal plane is continuously adjusted, and the detection of the robot space error can be realized through a sufficient number of measurements.

Description

technical field [0001] The invention relates to a robot, in particular to a method for calibrating space errors of a six-axis joint industrial robot based on a ballbar. Background technique [0002] The six-axis articulated industrial robot is an open-chain structure consisting of coupled motions of adjacent links. The pose of the end effector requires independent and precise control of the parameter values ​​of each joint. The inherent error of the robot is inevitable, which makes the internally defined kinematics model in the controller unable to accurately describe the actual pose, causing the theoretical pose of the robot to deviate from the actual pose. Therefore, it is of great significance to use an appropriate method to calibrate the structural mechanism parameters of the robot to improve the control accuracy of the robot. [0003] At present, many robot calibration methods have been proposed. Through the existing patent search, the following prior art is found: 1. ...

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Problems solved by technology

[0003] At present, many robot calibration methods have been proposed. Through the existing patent search, the following prior art is found: 1. The Chinese patent application with the application number 201610880648.1 discloses a method of using a ballbar to calibrate the structural parameters of a robot. The idea is to solve the structural parameters of the robot according to the parallelogram principle by measuring the parameters through experiments. The required experimental instruments and experimental processes are complex and cumbersome, and too much human intervention will inevitably introduce human errors and cause inaccurate experimental results; 2. Chinese patent application with application number 201510416268.8 A simple calibration device and calibration method for the kinematic parameters of an industrial robot is disclosed. The measuring tool used is a dial gauge, so the accuracy is difficult to guarantee, and according to the patent, the perpendicularity of the two mutually perpendicular calibration blocks cannot be guaranteed; 3. Application The Chinese patent application No. 201510288034.X discloses a two-dimensional plane roundness error calibration method for a large-stroke linkage mechanism. This patent is based on the ballbar to detect the motion accuracy of CNC machine tools and effectively solves the problem of large-stroke two-dimensional plane errors. Calibration method, but the method described is only limited to the plane angle and cannot calibrate the error of the CNC machine tool from the perspective of space

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