A sliding mode controller for vehicle active suspension systems with non-linearities

Abstract

In this paper, the control of an active suspension system using a quarter car model has been investigated. Due to the presence of non-linearities such as a hardening spring, a quadratic damping force and the ‘tyre lift-off’ phenomenon in a real suspension system, it is very difficult to achieve desired performance using linear control techniques. To ensure robustness for a wide range of operating conditions, a sliding mode controller has been designed and compared with an existing nonlinear adaptive control scheme in the literature. The sliding mode scheme utilizes a variant of a sky-hook damper system as a reference model which does not require real-time measurement of road input. The robustness of the scheme is investigated through computer simulation, and the efficacy of the scheme is shown both in time and frequency domains. In particular, when the vertical load to the sprung mass is changed, the sliding mode control resumes normal operation faster than the nonlinear self-tuning control and the passive system by factors of 3 and 6, respectively, and suspension deflection is kept to a minimum. Other results showed advantages of the sliding mode control scheme in a quarter car system with realistic non-linearities.

Non-Linear Predictive Control of Multi-Input Multi-Output Vehicle Suspension System

“…The physical values of vehicle suspension parameters are presented in Table 1. These values are related to a typical light commercial car and have been selected near the values of different half car models reported in prevalent papers [7,9,14].…”

Development Using Simulation on a 4-DOF Passive Suspension System with Thorax-Pelvis

“…Finer design of passive suspension system is necessary to improve the vehicle quality. There are two main objectives of passive suspension system, one is to isolate the external disturbance by road irregularities on the car body from passengers to enhance ride comfort and other is to keep firm contact between the tyres and the road to provide good road holding [8]. However, both of these aims for conflicting requirements.…”

Dual objective active suspension system based on a novel nonlinear disturbance compensator

“…Due to their fixed configuration, the performance of the passive systems is limited compared to the active systems. Over the years, a large number of control strategies such as, optimal control, [1,2] adaptive control, [3,4] model reference adaptive control, [5,6] H ∞ , [7] linear quadratic regulator (LQR) control, [8] fuzzy sliding mode control (SMC), [9] among others have been proposed in the literature for using the active device effectively.…”