Linear Quadratic Regulator Based Control Device for Active Suspension System with Enhanced Vehicle Ride Comfort

The suspension system is required in an automobile in order to absorb shock that comes from various type of disturbances such as irregular road profile, engine vibrations and wheel. Besides, the suspension plays an important part in enhancing the passenger ride comfort. The suspension will make sure that the tire is always contacted with the road for a better grip and braking. Conventionally, passive suspension has been used in car manufacturing that leads to huge vibrations that affect the ride quality. This is because ride comfort of passengers gets affected by overshoot and settling time of vehicle under vibration. Therefore, a good controller design is required to minimize the vibrations. In this research, an active suspension of quarter car model that considers only vertical movement is utilized in the suspension system. This paper presents a Linear Quadratic Regulator (LQR) method to enhance the vehicle ride comfort towards the vibration of the suspension system. The control design approach is then compared with the classical control which is the Proportional Integral Derivative (PID) that is set as a benchmark control. The results for both controllers are evaluated through simulations in MATLAB and Simulink Software. Other than using the passenger vehicle parameters, the parameters of bus are also tested into the system to investigate the vehicle performance by taking the bumps and road pavements as road disturbances. The results obtained from the simulations show that the responses of the quadratic based approach give the significant improvement in minimizing the vibration and fast settling time compared to passive and PID control.