Active nonlinear partial-state feedback control of contacting force for a pantograph–catenary system

• Published in: ISA transactions 2019-08, Vol.91, p.78-89
• Main Authors: Zhu, Bing, Ren, Zhiling, Xie, Wenjing, Guo, Fengyi, Xia, Xiaohua
• Format: Article
• Language: English
• Subjects: Backstepping; Observer; Pantograph–catenary system; Trajectory tracking
• ISSN: 0019-0578; 1879-2022
• DOI: 10.1016/j.isatra.2019.01.033

In this paper, a nonlinear partial-state feedback control is designed for a 3-DOF pantograph–catenary system by using backstepping approach, such that the contacting force of the closed-loop system is capable of tracking its reference profile. In the control design, the pantograph–catenary model is transformed into a triangular form, facilitating the utilization of backstepping. Derivatives of virtual controls in backstepping are calculated explicitly. A high-order differentiator is designed to estimate the unknown time derivatives of elasticity coefficient; and an observer is proposed to reconstruct the unmeasurable states. It can be proved theoretically that, with the proposed nonlinear partial-state feedback control, the tracking error of the contacting force is ultimately bounded with tunable ultimate bounds. Theoretical results are demonstrated by numerical simulations. •The backstepping approach is firstly applied to control design for pantograph–catenary system.•The closed-loop system is capable of tracking not only constant reference contacting force but also time-varying periodic reference forces.•A high-order differentiator is designed to approximate the unknown derivatives of time-varying elasticity coefficient.•A simple observer is designed to reconstruct the un-measurable system states.