A zero calibration method for an industrial robot

Abstract

The invention discloses an industrial robot zero position defining method. The industrial robot zero position defining method comprises the steps that a double-shaft dip angle sensor is arranged on a second shaft, a dip angle sensor coordinate system keeps parallel to a second-shaft coordinate system, and two dip angles (namely reference zero positions) of a robot base and a zero position angle of the second shaft are obtained by controlling movement of a first shaft and the second shaft; then the double-shaft dip angle sensor is arranged on a sixth shaft, the dip angle sensor coordinate system keeps parallel to a sixth-shaft coordinate system, and the zero position of a third shaft, the zero position of the fourth shaft, the zero position of the fifth shaft and the zero position of the sixth shaft are obtained in an identification method. According to the industrial robot zero position defining method, zero defining of a whole robot can be achieved by two times of instrument installation and manual operation, manufacturing costs of an auxiliary clamp and an installation surface (or an installation hole) of the robot are saved, the zero position aligning accuracy of the robot can be improved, and operation time of zero position defining is shortened.

Description

technical field [0001] The invention belongs to the calibration technology of industrial robots, in particular to a joint zero calibration method of a 6-degree-of-freedom industrial robot. Background technique [0002] Robot precision can be divided into repetitive positioning accuracy and absolute positioning accuracy. The former is mainly determined by factors such as joint hysteresis and control resolution, while the latter is mainly composed of errors such as DH parameters, joint and connecting rod deformation. With the application of robot-specific reducers and servo control systems, the repetitive positioning accuracy of robots has approached the limit level of current manufacturing technology, but there is still a lot of room for improvement in absolute positioning accuracy. In recent years, the application of new technologies such as offline programming technology and robot vision control technology has emerged in an endless stream, and the requirements for absolute ...

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Problems solved by technology

Among the above two methods, although the former method has high precision, it is generally used in scientific research activities due to the complicated operation process and expensive measuring equipment. The latter method has been manufactured by robots because of its simple principle and practical method. widely used by vendors

[0004] Although the latter method is easy to operate, it needs to process the positioning hole or positioning surface of the robot in advance, and manufacture the corresponding auxiliary fixtures, and the calibration process requires each axis to be calibrated one by one, and the corresponding fixtures need to be installed for each calibration ( Generally, a robot with 6 degrees of freedom needs to be installed at least 4 times), and the robot joints need to be adjusted continuously during calibration. The whole process is very time-consuming and the accuracy is far less than the previous method.

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