Robust controller design of four wheel steering systems using mu synthesis techniques

摘要

In this paper, a linearized four wheel steering (4WS) system model is deduced and then modified into a form which is appropriate for applying Matlab (mu) Toolbox to design robust controller. Several important topics are discussed in detail, such as (1) how to make system set-up match Matlab (mu) Toolbox requirement, (2) how to select weights based on plant's uncertainty, (3) how to solve controller discretization problem, and (4) how to adjust the system so that the conditions necessary for using a state-space formula to solve H(infinity) optimal (sub-optimal) problem and performing the Matlab (mu) Toolbox D--K iteration procedure are satisfied. Finally simulation results of robust controller and a PID controller are compared.