Adaptive sliding mode control of nonlinear robotic systems with time-varying parameters

1994 ◽  
Vol 23 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Chun-Yi Su
Author(s):  
Bingxin Ma ◽  
Yongfu Wang

The steering-by-wire (SbW) system is one of the main subsystems of automatic vehicles, realizing the steering control of autonomous vehicles. This paper proposes an event-triggered adaptive sliding mode control for the SbW system subject to the uncertain nonlinearity, time-varying disturbance, and limited communication resources. Firstly, an event-triggered nested adaptive sliding mode control is proposed for SbW systems. The uncertain nonlinearity is approximated by the interval type-2 fuzzy logic system (IT2 FLS). The time-varying disturbance, modeling error, and event-triggering error can be offset by robust terms of sliding mode control. The key advantage is that the high-frequency switching of sliding mode control only appears on the time derivate of control input without increasing the input-output relative degree of closed-loop SbW systems, such that the chattering phenomenon can be eliminated. Finally, theoretical analysis shows that the practical finite-time stability of the closed-loop SbW system can be achieved, and communication resources in the controller-to-actuator channels can be saved while avoiding the Zeno-behavior. Numerical simulations and experiments are given to evaluate the effectiveness of the proposed method.


Author(s):  
Khadija Dehri ◽  
Ahmed Said Nouri

The problem of sensitivity to uncertainties and disturbances is still a challenging task in the theory of discrete sliding mode controller. In this article, a discrete repetitive adaptive sliding mode control using only input-output measurements of linear time-varying system with periodic disturbances is proposed. A new indirect adaptive algorithm taken into account the periodicity of disturbances is used to identify parameter variations of the considered system. Based on this identification, discrete sliding mode controller is developed. Then, the structure of plug-in repetitive control is integrated into the previous controller to reject harmonic disturbances. A robustness analysis is achieved to ensure the asymptotic stability of the proposed controller. An example of time-varying DC-DC buck converter subject to harmonic disturbances is carried out to illustrate the effectiveness of the designed discrete repetitive adaptive sliding mode control.


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