Khisbullah Hudha

Effects of control techniques and damper constraint on the performance of a semi-active magnetorheological damper

Semi-active dampers change their damping force in real time by simply changing the damping coefficient according to a control policy. In this study, a number of semi-active control algorithms namely modified skyhook, modified groundhook and modified hybrid skyhook-groundhook controllers are evaluated to be used with a magnetorheological damper. The effectiveness of these control algorithms in disturbance rejection are investigated along with their ability to consistently provide the target force in the same direction with the damper velocity to overcome the damper constraint. From the simulation and experimental results, the modified hybrid skyhook-groundhook controller shows significant improvement in body acceleration, body displacement, suspension displacement without allowing excessive wheel acceleration magnitude. The modified hybrid skyhook-groundhook controller is also superior to the counterparts in overcoming the damper constraint by producing the target forces consistently in the same sign with the damper velocity.

Pid Controller with Roll Moment Rejection for Pneumatically Actuated Active Roll Control (ARC) Suspension System

This chapter presents a successful implementation of PID controller for a pneumatically actuated active roll control suspension system in both simulation and experimental studies. For the simulation model, a full vehicle model which consists of ride, handling and tire subsystems to study vehicle dynamics behavior in lateral direction is derived. The full vehicle model is then validated experimentally using an instrumented experimental vehicle based on the driver input from the steering wheel. Two types of vehicle dynamics test are performed for the purpose of model validation namely step steer test and double lane change test. The results of model validation show that the behaviors of the model closely follow the behavior of a real vehicle with acceptable error. An active roll control (ARC) suspension system is then developed on the validated full vehicle model to reduce unwanted vehicle motions during cornering maneuvers such as body roll angle, body roll rate, vertical acceleration of the body and body heave. The proposed controller structure for the ARC system is PID control with roll moment rejection loop. The ARC system is then implemented on an instrumented experimental vehicle in which four units of pneumatic actuators are installed in parallel arrangement with the passive suspension system. The 1