Robust nonfragile H∞ optimum control for active suspension systems with time-varying actuator delay

Abstract

The active suspension has drawn considerable attention due to its superiority in improving the vehicle vertical dynamics. This paper investigates robust nonfragile H∞ optimal control for the vehicle active suspension with time-varying actuator delay. Firstly, the dynamic equation of an active suspension system with actuator delay is established in terms of the main performance objectives, that is, ride comfort, handling ability, and road holding. Then, a robust nonfragile H∞ optimal controller is proposed to deal with the problem of active suspension control with time delay and actuator uncertainty, which is based on Lyapunov theory, convex optimization, and the linear matrix inequality approach. Finally, a quarter-car test rig is used for an experiment to illustrate the effectiveness of the proposed controller. Simulation and experimental results demonstrate that the proposed controller can ensure the asymptotic stability of the closed-loop system with bounded time-varying actuator delay, while managing the tradeoff between the conflicting performances and achieving performance optimization for the active suspension.

Design and performance comparison of interconnection and damping assignment passivity-based control for vibration suppression in active suspension systems

“…This profile mimics a realistic case of transient bump disturbance which can occur on the road. This profile is taken similar to that of a profile used in Li et al (2019) and Alves et al (2014). A peak value of 0.03 m, which is the maximum value of disturbance x r ( t ) considered for the design of the controller, is considered as the input to test the performance of the controller.…”

“…Vibration isolation of passengers due to road irregularities requires softer suspension, whereas harder suspension achieves good road holding (Aoki et al, 2012). These conflicting requirements make the control design complex (Li et al, 2019). On the other hand, the control design must take into account the limits of suspension deflection to obey the constraints and shun the damage of the suspension.…”

“…Optimal control using linear quadratic regulator (LQR) is designed, and simulation results are presented for the active suspension system half-car model in Taghirad and Esmailzadeh (1998). Vibration control of a quarter-car active suspension system using H-infinity control is presented in Li et al (2019Li et al ( , 2013. Active vibration control of a piezoelectric Stewart platform using fuzzy logic control is presented in Bahrami et al (2013Bahrami et al ( , 2014.…”

A research of sliding mode control method with disturbance observer combining skyhook model for active suspension systems

“…However, active suspension systems (ASSs) can solve this issue. This is mainly attributed to the actuator mounted between the sprung mass and unsprung mass, which can provide active vibration control for the sprung mass by adding/dissipating energy to/from ASSs (Li et al, 2019a, 2019b).…”

“…Based on a simple 2DOF model, many control approaches are investigated for ASSs. Those approaches include a linear quadratic regulator (LQR) (Taghirad and Esmailzadeh, 1998), H ∞ (Gao et al, 2000; Li et al, 2019a, 2019b), sliding mode control (SMC) (Chen et al, 2017), back-stepping (Sun et al, 2013), disturbance filter (Copot et al, 2018) and so on. The SMC is a variable structure control and has been applied in both the linear and nonlinear systems with external disturbance (Ionescu and Muresan, 2015).…”