• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2022, Vol. 58 ›› Issue (14): 181-189.doi: 10.3901/JME.2022.14.181

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Force-Position Composite Control Method for Trajectory Accuracy Compensation of Industrial Robots

LU Yuan1,2,3, GUO Kai1,2,3, SUN Jie1,2,3   

  1. 1. Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Ministry of Education, Shandong University, Jinan 250061;
    2. Research Center for Aeronautical Component Manufacturing Technology and Equipment, Shandong University, Jinan 250061;
    3. School of Mechanical Engineering, Shandong University, Jinan 250061
  • Received:2021-06-30 Revised:2021-09-30 Online:2022-07-20 Published:2022-09-07

Abstract: The low joint stiffness of industrial robots and the low machining accuracy under the interference of external load have become the main obstacles to further promotion and application of robots in machining systems. A compound compensation method of force feedforward control and position feedback control is proposed to solve this problem. The force feedforward control part can compensate for the position deviation caused by external load force in advance, and the position feedback part is used to compensate for the position deviation caused by internal factors. A closed-loop control system for online compensation of trajectory error is constructed using a six-dimensional force sensor and a laser tracker. An online compensation experiment is carried out to verify the compensation effect of the proposed method. The errors caused by internal parameters and external environmental factors are considered comprehensively in the method, which improves the tracking accuracy of the robot and can realize the precise control of the robot. The experimental results show that the proposed method is robust and can maintain high trajectory tracking accuracy under large external loads. Under 200 N impact load, the peak error of path trajectory is 0.082 mm, and the stability error is 0.047 mm, which lays a foundation for high precision robot machining under complex working conditions.

Key words: industrial robot, trajectory accuracy, compound control, load disturbance

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