Positional Accuracy Improvement of an Industrial Robot Using Feedforward Compensation and Feedback Control

Industrial robots play an important role in the transformation and upgrading of aviation manufacturing technology by their advantages of high flexibility, high efficiency, and low costs compared to the conventional computerised numerical control machine. However, due to the serial structure design of the main body, the industrial robot has low absolute positional accuracy, which limits its popularization and application in the field of high-precision manufacturing. The purpose of this paper is to develop a robot accuracy improvement method using feedforward compensation and joint closed-loop feedback correction considering the influence of joint backlash. The experimental results show that the positional error of the compensated robot by the proposed method is reduced from 0.76 mm to 0.18 mm under no-load conditions, and the hole's positional accuracy is to 0.25 mm in the robotic drilling experiment.