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Previous work to examine the performance of a variety of control strategies for a switchable damper suspension system is extended to include an adaptive suspension. The aim of this adaptation algorithm is to maintain optimal performance over the wide range of input conditions typically encountered by a vehicle. The adaptive control loop is based on a gain scheduling approach and two strategies are examined both theoretically and experimentally using a quarter vehicle test rig. For the first strategy, the gains are selected on the basis of root mean square (r.m.s.) wheel acceleration measurements whereas in the second approach the r.m.s. value of suspension working space is used. A composite input is used consisting of sections of a road input disturbance of differing levels of magnitude in order to test the control systems' abilities to identify and adapt efficiently as the severity of the road input changes.

It is now widely accepted that electronically controlled suspension systems can offer substantial improvements over passive designs. However, much of the published work is based on idealised, theoretical calculations and practical developments have indicated that component limitations play a major part in governing the potential benefits available. In this work, the detailed response characteristics of a three-state switchable damper are first measured on a laboratory rig. The switching dynamics between states are characterised for both bump and rebound behaviour. Then, the performance of this damper in combination with a self levelling, hydro-pneumatic suspension is examined both theoretically and experimentally using a quarter vehicle rig. The issue of compensating for component limitations in the control system design is examined and shown to be an important feature in extracting the best ride performance from switchable damper systems.