Self-adaptive machining method for manipulator

Abstract

The invention provides a self-adaptive machining method of a manipulator. A sensor for acquiring a contact force value of the manipulator and a workpiece is arranged at the tail end of the manipulator, and a machining tool is arranged on the sensor. The machining method comprises the steps of establishing a model, initially contacting, stably machining and the like, through generating an explicitpath function and compensating a path error according to a feedback value of the force value detected by the sensor, force and position hybrid control is achieved, the machining stability is relatively good, and the machining precision is relatively high. Moreover, as a machining tool contacts with a machining surface in the tangential direction of the surface of the workpiece, after the machiningtool contacts with the surface of the workpiece along a machining path to reach an expected contact force, the normal component speed of the contact surface is zero, stable contact between the machining tool and the workpiece is achieved, big collision cannot occur, and the machining stability is further improved.

Description

technical field [0001] The invention relates to an automatic processing method, in particular to an adaptive processing method of a manipulator. Background technique [0002] The traditional manipulator grinding system usually adopts the teaching method of processing. The manipulator adopts the teaching path or the offline generation path. The working path of the manipulator relies heavily on hard-coded actions. The ability of the manipulator to adapt to the dynamic changing environment is limited. deformation, clamping position error of the fixture, positioning error of the robot arm and the worktable, etc.), complex installation, debugging and operation, and the error of the workpiece size and the actual environment will lead to position deviation between the actual processing trajectory of the manipulator and the theoretical processing trajectory, which will cause A large impact force is generated, which will damage the workpiece and the manipulator, and the processing s...

AI Technical Summary

Problems solved by technology

The manipulator adopts the teaching path or offline generation path. The working path of the manipulator relies heavily on hard-coded actions. The ability of the manipulator to adapt to the dynamic changing environment is limited. deformation, clamping position error of the fixture, positioning error of the robot arm and the worktable, etc.), complex installation, debugging and operation, and the error of the workpiece size and the actual environment will lead to position deviation between the actual processing trajectory of the manipulator and the theoretical processing trajectory, which will cause A large impact force is generated, which will damage the workpiece and the manipulator, and the processing stability is relatively poor

[0003] The Chinese invention patent application with the publication number CN108115690A discloses a manipulator adaptive control system and method, which adopts an adaptive impedance control algorithm based on force feedback, and the algorithm uses the normal deviation force to perform impedance control model calculations to obtain the position correction point However, when the manipulator is used for processing (such as grinding and polishing), the abrasive tool at the end of the manipulator needs to keep in contact with the workpiece. The vibration generated by the operation of the abrasive tool and the vibration force generated during the machining process will cause the manipulator to be unstable on the surface of the workpiece At the same time, the impedance controller cannot guarantee that the manipulator will not rebound on the surface after the first contact impact during the transition process of the manipulator from free space to contact with the workpiece, and the stability is difficult to guarantee

In addition, the processing speed of the above method is relatively slow. When designing the control algorithm, the surface grinding process is regarded as a static process, and the sensor value deviation caused by the change of motion acceleration and non-horizontal downward attitude of the sensor at the end of the manipulator during surface processing is not considered. , affecting the machining accuracy

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