Research On Industrial Robot Accuracy Compensation Technology Based On Joint Rotation Feedback

Recently,the requirements of the aircraft manufacturing technology for high quality and efficiency have been put forward by the aviation industry.Meanwhile,the industrial robot technology,with its distinct advantages,such as high flexibility,low cost,minimal installing disruption and large working volume,may provide a practicable solution for fulfilling these demands.However,limited by its poor absolute positioning accuracy and low rigidity during processing,a traditional industrial robot could not meet the demanded precision in the aviation industry,so a robot accuracy compensation technology,which is based on joint rotation feedback,has been proposed in this paper,aiming to increase the absolute positioning accuracy of a robot.The main researches are as follows:1)Robot kinematic error models,which cover the influences from geometric parameter errors,self-gravity and external loads,have been established.Based on which,practical compensation strategies have been summarized for robot accuracy compensation technologies,which are either based on online detection or offline calibration.And a compensation strategy for this joint-rotation-feedback based robot accuracy compensation technology,had also been put forward.2)According to the specific structure and geometry of a KUKA KR210 robot,relevant model selection,installation and calibration of the joint rotation feedback encoders have been carried out.And via the joint rotation feedback,the other geometric parameter errors could be calibrated to further revise the nominal kinematic model of this robot.Then,relevant configurations have been done to the unrealtime and realtime control environments,KRL and RSI,of this robot.Finally,the relevant control procedures for this joint-rotation-feedback based robot accuracy compensation technology are elaborated.3)The overall scheme of the control system,which matches this joint-rotation-feedback based robot accuracy compensation technology,has been put forward.It mainly comprised the modular designs for hardware configuration and stratified setups for the software configuration.By adopting a structure-and-component based principle,the integrated control software,among the software configuration,has been developed.4)A platform and the relative coordinate systems have been built up to evaluate this joint-rotation-feedback based robot accuracy compensation technology.Experimental results show that this technology could increase the robot’s absolute positioning accuracy from 1.0 mm to 0.25 mm with good performance.