Study On Integrated Control Of Vehicle Electric Power Steering And Active Suspension System For Disturbance Suppression

Automobile is disturbed by a lot of outside interferences while driving, whichmakes negative influence on the full vehicle performances, such as maneuverability,safety and ride comfort etc. In consideration of some important disturbances, theH_∞ output feedback controller is designed for Electric Power Steering (EPS) andActive Suspension System (ASS) with the theories of the linear and nonlinearH_∞ control in this paper. The designed controller improves the vehiclemaneuverability, handiness and ride comfort, and suppresses the body movementseffectively. Firstly, the full vehicle model with 9 DOF based on horizontal andvertical dynamics is constructed. And the simulation is made to validate themathematical model. Secondly, owing to the complexity and localization in thenonlinear system design, the nonlinear part is regarded as the perturbation of themodel. The weighting function and boundary function of the uncertainty are chosenby controlled objective, and the extended controlled objective matrix is established.Thus, the standard H_∞ control algorithm is obtained from robust performancecontrol. Thirdly, the nonlinear H_∞ output feedback controller is designed for EPSand ASS under the considerations of the random road and the strong crosswind withthe L₂-gain method of disturbance suppression. Simulations for driver-vehicle-roadclosed-loop system are carried out in confirmation of the availability of the controlscheme. Finally, according to the control scheme, the software is designed based onthe integrated electric controller hardware. The vehicle tests are carried out, and theresults confirm the validity of the integrated controller again.