Traditional industrial robots have advantages of large workspace

compact structure

and good flexibility

and have been gradually used in the high precision metal cutting fields of drilling

milling and grinding instead of material handling

spot welding

spray painting and other operations. However

the stiffness of industrial robots is weak compared with metal cutting machine tools. The weak stiffness of the robot makes the tool deviate from the desired machining trajectory

and makes the robot easy to chatter when it is subjected to the external excitation force

which affects the machining accuracy of the robot; in addition

the internal backlash of the joint reducers is also one of the most important factors affecting the machining accuracy of the robot. The research status of robot stiffness optimization

robot machining error compensation

backlash compensation of the robot and vibration suppression of the robot are summarized. Two kinds of robot structure improvement design are proposed to increase the accuracy of the robot

the robot structure of non-backlash driving based on dual-motor drive and the high stiffness robotic arm based on parallelogram mechanisms are respectively described. And the structural characteristics of the robot are elaborated.