Improving Ride Comfort Using Control Systems Design for Active Damper
Examensarbete för masterexamen
There is a great demand for improvements in ride comfort of high-end passenger cars. Heave, roll and pitch motions might negatively affect ride comfort. In this regard, active and passive components are often integrated to improve vehicle dynamics performance. One of the challenges for automotive industry is to design controllers for active components used in the suspension system. The main focus here is to replace front and rear passive dampers with a set of active dampers integrated in parallel with coil springs within the suspension system. Such a setup can improve the overall performance of the vehicle by inducing or dispersing energy. Furthermore, it can reduce weight and energy consumption. However, such an active system might bring extra oscillation and disturbances to the vehicle. Hence, the integrated active dampers should be well controlled in order to operate as expected. The main objective of this study is to design a suitable control algorithm for the active dampers. A full vehicle model with 7 degrees of freedom (DOF) is validated in IPG CarMaker and used for the control design. Three different controllers are designed in Matlab: sky-hook controller, optimal controller with LQR method and robust controller with H1 method. The challenging part is tuning the parameters and weight selections for controllers. The controllers performances are verified and tested in IPG CarMaker and compared to the performance of a conventional passive suspension system. An overall improvement of the ride comfort is achieved in the simulations. It is recommended that the solutions are further assessed and developed in production vehicles and/or balancing with other performance indicators than comfort, such as handling and longitudinal performance.
Active suspension , ride comfort evaluation , robust control , optimal control , active damper , vehicle dynamics