Sliding mode control of excavator electro-hydraulic system based on linear extended state observer

Abstract

The actual working environment of unmanned excavation robot is harsh. In order to improve the trajectory tracking accuracy of bucket under load disturbance, a nonlinear mathematical model of electro-hydraulic system of digging robot was established, and a sliding mode controller(SMC)based on linear extended state observer(LESO), called SMC-LESO, was designed. Based on the displacement signal of the piston rod of the bucket cylinder, the velocity, the acceleration, the load disturbance and uncertain factors of the system were estimated by the LESO. On this basis, SMC-LESO was completed, and the Lyapunov stability of the controller was proved. The co-simulation model of electro-hydraulic proportional control system of the excavator was established. Compared with proportional-integral-derivative (PID) controller and SMC, the simulation results show that the designed controller can effectively suppress the disturbance, and has high displacement tracking accuracy and robustness.

Keywords

unmanned excavation robot / electro-hydraulic system / linear extended state observer(LESO) / sliding mode controller(SMC) / displacement tracking control

References

[1] ZHAO J, LONG P, WANG L, et al. AES: Autonomous excavator system for real-world and hazardous environments.2022-12-31]. DOI:10.48550/arXiv.2011.04848.

[2] FENG H, YIN C, LI R, et al. Flexible virtual fixtures for human-excavator cooperative system. Automation in Construction, 2019, 106: 102897.

[3] YANG K S, LIU J, GU Y M, et al. On the anti-interference of electro-hydraulic control system for excavator's digging bucket arm. Journal of Northeastern University (Natural Science Edition), 2010, 31(5): 713-718.

[4] LIU G, YANG L, WU D, et al. Development and experimental investigation of an automatic control system for an excavator. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2020, 235(4): 758-73.

[5] WANG X. Fuzzy-PID control in electro-hydraulic proportional valve system//IEEE International Conference on Computer-aided Industrial Design & Conceptual Design, November 17-19, 2010, Yiwu, China. New York: IEEE, 2020: 1454-1457.

[6] YE Y, YIN C B, GONG Y, et al. Position control of nonlinear hydraulic system using an improved PSO based PID controller. Mechanical Systems and Signal Processing, 2017, 83: 241-59.

[7] FENG H, YIN C B, WENG W W, et al. Robotic excavator trajectory control using an improved GA based PID controller. Mechanical Systems and Signal Processing, 2018, 105: 153-168.

[8] FENG H, YIN C, MA W, et al. Parameters identification and trajectory control for a hydraulic system. ISA Transactions, 2019, 92: 228-240.

[9] LI B, YAN J, GUO G, et al. High performance control of hydraulic excavator based on Fuzzy-PI soft-switch controller//IEEE International Conference on Computer Science and Automation Engineering, June 10-12, 2011, Shanghai, China. New York: IEEE, 2011: 676-679.

[10] HASSAN M Y, KOTHAPALLI G. Interval Type-2 fuzzy position control of electro-hydraulic actuated robotic excavator. International Journal of Mining Science and Technology, 2012, 22(3): 437-445.

[11] CHEN H. Research of the electro-hydraulic servo system based on rbf fuzzy neural network controller. Journal of Software, 2012, 7(9): 1960-1967.

[12] LYU G M, SUN L N, XUE Y. BP network control over the track of working device of hydraulic excavator. Chinese Journal of Mechanical Engineering, 2005, 41(5): 119-122.

[13] PI Y, WANG X. Trajectory tracking control of a 6-DOF hydraulic parallel robot manipulator with uncertain load disturbances. Control Engineering Practice, 2011, 19(2): 185-193.

[14] XU J, YOON H S. Sliding mode control of hydraulic excavator for automated grading operation. SAE International Journal of Commercial Vehicles, 2018, 11(2): 1.

[15] XU Y, LIU K. Sliding mode impedance control for the excavator’s electrohydraulic system. Machine Tool & Hydraulics, 2015, 43(22): 138-141.

[16] LIU K. Research on electro-hydraulic control technology of robotic excavator’s working device. Xi’an: Northeastern University, 2009.

[17] WANG H J. Research on an adaptive sliding mode control strategy for electro-hydraulic position servo system. Shanghai: Shanghai Jiao Tong University, 2017.

[18] BAI Y, PING L. Adaptive fuzzy sliding mode control for Electro-hydraulic position servo system//IEEE 2010 Chinese Control and Decision Conference, May 26-28, Xuzhou, China. New York: IEEE, 2010.DOI: 10.1109/CCDC.2010.5498613

[19] ZHU N. Electro-hydraulic position active disturbance rejection control of asymmetric valve-controlled cylinder. Electrokinetic Tool, 2020(1): 19-23.

[20] LI Y. Study on bucket trajectory and swing torque control for the autonomous hydraulic excavator. Hangzhou: Zhejiang University, 2018.

[21] YAO W L, QI G H, CHI R H, et al. Model-free adaptive control for water well drilling rig electro-hydraulic servo with unknown load disturbance. Control Theory & Applications, 2022, 39(2): 231-240.

[22] HAN J Q. Active disturbance rejection control technique – the technique for estimating and compensating the uncertainties. Beijing: National Defense Industry Press,2008.

[23] HAN J Q. From PID technique to active disturbances rejection control technique. Control Engineering of China, 2002(3): 13-18.

[24] YANG W Q, LU J H, JIANG X, et al. Design of quadrotor attitude active disturbance rejection controller based on improved ESO. Systems Engineering and Electronics, 2021, 32: 1-9.

[25] WANG L X, ZHAO D X, LIU F C, et al. Linear active disturbance rejection control for a class of electro-hydraulic position servo system with light load. Control Theory & Applications, 2021, 38(4): 503-515.

[26] YU B, LI X B, YAO J, et al. Study on active disturbance rejection control of electro hydraulic servo system for 60 MN hydraulic press. Forging & Stamping Technology, 2015, 40(9): 74-79.

[27] GAO Z. Scaling and bandwidth-parameterization based controller tuning//The American Control Conference, June 4-6, 2003, Denver, Cororado. New YORK: IEEE, 2003: 4989-4995.

[28] HUANG J Z, CEN Y W, YE X H, et al. Variable load sliding mode control for manipulator based on linear extended state observers. Machine Tool & Hydraulics, 2021, 49(13): 45-50.