Sliding mode control for a model of an electrohydraulic actuator system with discontinuous nonlinear friction

Author(s):  
Shu Wang ◽  
S. Habibi ◽  
R. Burton ◽  
E. Sampson
Author(s):  
Shu Wang ◽  
Richard Burton ◽  
Saeid Habibi

A common problem pertaining to linear or nonlinear systems is the design of a combined robust control and estimation strategy that can effectively deal with noise and uncertainties. The variable structure control (VSC) and its special form of sliding mode control (SMC) demonstrate robustness with regard to uncertainties, although their performance can be severely degraded by noise. As such they can benefit from using state estimates obtained from filters. In this regard, this paper considers the use of a recently proposed robust state and parameter estimation strategy referred to as the variable structure filter (VSF) in conjunction with SMC. The contribution of this paper is a new strategy that combines sliding mode control with the variable structure filter. In the presence of bounded parametric uncertainties and noise, this combined method demonstrates robust stability both in terms of control and state estimation. Furthermore, the combined strategy can be used to achieve high regulation rates or short settling time. The combined VSF and SMC strategy is demonstrated by its application to a high precision hydrostatic system, referred to as the electrohydraulic actuator system.


Author(s):  
Shu Wang ◽  
Richard Burton ◽  
Saeid Habibi

A new robust state and parameter estimation strategy called the Variable Structure Filter (VSF) has recently been proposed and used for state and parameter estimation. A very common problem of linear stochastic systems is to design a combined robust control and estimation strategy, given system and noise uncertainties. Variable Structure Control (VSC) and its special form of Sliding Mode Control (SMC) show superb robustness. This paper proposes a new strategy involving the Sliding Mode Control and the Variable Structure Filter. Both the estimator and controller are based on the concepts of Variable Structure Systems (VSS). In the presence of bounded parametric uncertainties and noise, a robust stability is guaranteed. Further more, the combined strategy can be used to achieve high regulation rates or short settling times. The object of this paper is to introduce this combined VSF and SMC strategy and to demonstrate its application to a third order model of a high precision hydrostatic system, referred to as the Electrohydraulic Actuator System (EHA).


Actuators ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 154
Author(s):  
Bin Wang ◽  
Pengda Ren ◽  
Xinhao Huang

A piston piezoelectric (PZT) pump has many advantages for the use of light actuators. How to deal with the contradiction between the intermittent oil supplying and position control precision is essential when designing the controller. In order to accurately control the output of the actuator, a backstepping sliding-mode control method based on the Lyapunov function is introduced, and the controller is designed on the basis of establishing the mathematical model of the system. The simulation results show that, compared with fuzzy PID and ordinary sliding-mode control, backstepping sliding-mode control has a stronger anti-jamming ability and tracking performance, and improves the control accuracy and stability of the piezoelectric pump-controlled actuator system.


Author(s):  
Xianqing Wu ◽  
Kexin Xu

This article is motivated by the control issues of the translational oscillator with rotational actuator system in the existence of uncertain disturbances. A nonlinear disturbance observer and a global sliding mode control method are proposed for the disturbance estimation and stabilization of the translational oscillator with rotational actuator system. Compared with the existing control methods, uncertain disturbances are estimated by the proposed nonlinear disturbance observer. In addition, the sliding mode control method is continuous and global robustness with respect to disturbances. Specifically, to facilitate the controller design, the dynamics of the translational oscillator with rotational actuator system are rearranged as the cascade form first. Then, a virtual signal is constructed and corresponding error dynamics are derived. Subsequently, a nonlinear disturbance observer and a continuous global sliding mode control method are proposed for the disturbance rejection and stabilization of the translational oscillator with rotational actuator system. Finally, simulation results are provided to verify the effectiveness and robustness of the proposed controller.


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