Configuration development and optimization of hydraulically interconnected suspension for handling and ride enhancement

In this study, among 180 possible hydraulically interconnected suspension configurations, non-symmetric cases were eliminated and 24 potential configurations were selected for further investigation. A 14-DOF vehicle model capable of generating handling and ride motions is developed. At different manoeuvres and road inputs, the handling and ride performances are investigated for 24 configurations. Six hydraulic parameters are then optimized by the application of genetic algorithm in order to improve the ride. The handling performance is also investigated and results have shown that only four configurations provide better ride and handling performances simultaneously. The bounce acceleration response is shown to be reduced up to 47% for the four selected configurations. The roll and pitch angle responses were also reduced around 3% and 18% respectively. Four optimized configurations were also investigated under two sever ride and handling manoeuvres. It is shown that, for the vehicle with the optimized interconnected hydraulic suspension, the bounce acceleration response for a random road test is reduced up to 27% and the roll angle is reduced up to 18% for a side wind test.

Control Allocation Application to Automotive Suspension Actuators for Handling Objectives

Current research within the automotive community suggests an increasing trend in applying mechatronic actuators for improved ride and handling. In particular, there is an increasing trend towards semi-active and active suspension actuators. This research presents various novel suspension control strategies specific to handling by building upon a control allocation type framework. Such a framework is common in the aerospace and marine industries due its multi-objective control properties, suitability for over-actuated systems, the ease in which nonlinear or time-varying properties are included, in addition to many other benefits. Control allocation is becoming increasingly more appropriate for automotive applications due to the increasing trend in applying mechatronic actuators for improved ride and handling. Specifically, this paper develops methods for improving yaw rate with active suspension actuators. It will be shown that this task is nontrivial within an allocation framework due to properties of the physical system. By using the methods developed in this paper, it becomes trivial to incorporate this and other handling related methods into a larger and more integrated framework with a higher number of control objectives and actuators. The methods in this paper take advantage of the complicated dynamics and inherent nonlinear relationship between suspension actuator forces and resultant tire lateral forces. It is demonstrated through simulation that a vehicle with the proposed allocation framework outperforms a vehicle with no suspension actuation. Different methods are evaluated and compared based on stability and robustness properties.