Improvement of semi-active control suspensions based on gain-scheduling control

Hammood, HFH

Abstract

This study presents the development of a non-linear control strategy for a semi-active suspension controller using a gain-scheduling structure controller. The aim of the study is to overcome the constraints of conventional control strategies and improve semi-active suspension to achieve performance close to that of full active control. Various control strategies have been investigated to improve the performance of semi-active vibration control systems. A wide range of semi-active control strategies have also been experimentally tested by researchers in the attempt to enhance the performance of semi-active suspension systems. However, the findings published in the literature indicate that there appears to be a ceiling to performance improvements with the control strategies that have been proposed to date, which is about the half of what could be achieved with full active control. The main constraint for semi-active devices such as Magnetorheological (MR) dampers is that they are only capable of providing active control forces by dissipating energy, in their active mode, and they switch to work as simple passive dampers, the passive mode, when energy injection is demanded by the associated control laws. The split in durations of time between the active and passive modes for the conventional semi-active control strategies is around 50:50. This study will focus on the development of a novel semi-active control strategy that aims to extend the duration of the active mode and hence reduce the duration of the passive mode for semi-active suspensions by using a gain-scheduling control structure that dynamically changes the control force demanded by the operating conditions. The proposed control method is applied to both vertical and lateral suspensions of a railway vehicle in this study and the improvements in ride quality are evaluated with several different track data. For the purpose of performance comparison, a semi-active controller based on skyhook damping control integrated with MR dampers and also a vehicle with passive suspensions are used as the benchmark, and are used as a reference case for assessment of the proposed design. Numerical simulations are carried out to assess the performance of the proposed gain-scheduling controller. The simulation results obtained illustrate the performance improvement of the proposed control strategy over conventional semi-active control approaches, where the ride quality of the new controller is shown to be significantly improved and comparable with that of full active control. Potentially, this kind of adaptive capability with variable control approaches can be used to deliver the level of the performance that is currently only possible with fully active suspension without incurring the associated high costs and power consumption.

Citation

Hammood, H. (in press). Improvement of semi-active control suspensions based on gain-scheduling control. (Thesis). University of Salford

• Thesis Type: Thesis
• Acceptance Date: Oct 30, 2018
• Deposit Date: Nov 28, 2018
• Publicly Available Date: Nov 28, 2018