A hierarchical controller for the vibration of an automotive suspension system via magnetorheological dampers

Abstract

Reducing the vibration of an automotive magnetorheological (MR) suspension system can contribute greatly to enhancing vehicle performance. However, it is difficult to design a control system that depends on a complicated whole-vehicle vibration model. This paper proposes a hierarchical controller that consists of a control level and a coordination level for heave, roll, and pitch vibration control of a vehicle with an MR suspension system. On the control level, a local fuzzy controller is designed for each quarter-vehicle MR suspension system, based on a hybrid control strategy of skyhook control and groundhook control. On the coordination level, a coordination controller is designed to tune four local independent fuzzy controllers by adjusting their output parameters on the basis of system feedback. A test and control system for MR suspensions is set up and implemented on a minibus equipped with four controllable MR dampers. The results on random rough roads confirm that the hierarchical controller can reduce automotive vertical vibration, roll motion, and pitch motion more effectively than a passive suspension or an MR suspension using a hybrid control strategy. It achieves better ride comfort and automobile handling stability, although data for bump input indicate that the hierarchical controller does not decrease automotive vertical vibration more effectively than hybrid control or a passive system. However, it yields better results in decreasing pitch and roll motions.

Experimental Validation of a Hierarchical Suspension Control via MR Damper

“…In Savaresi and Spelta [2007], it has been shown that the skyhook logic approaches the filtering limit of a semi-active suspension; indeed, most of the literature is based on variations of this control logic which was first proposed in Karnopp [1995]. Variations of the skyhook logic can be found in Poussot-Vassal et al [2006], Song [2009], Yao et al [2002], Savaresi and Spelta [2008], Li et al [2009], Nie et al [2017]. The other aspect is the literature regarding the control of the damping force in a magnetorheological damper; in Sims et al [1997Sims et al [ , 2000, the authors developed a scheme to track a reference damping force in a MR damper by controlling the input current, regardless of the application (e.g., automotive).…”