Development of H∞ control strategy for a multi-wheeled combat vehicle

Abstract

A vehicle dynamics controller for an 8 x 8 heavy combat vehicle utilising both torque vectoring and third and fourth axle steering is propoed. The control scheme is composed of two controllers: a feedforward zero side slip (ZSS) controller actuates the third and fourth axle steering angles and a two DOF LPV H∞ controller that monitors steering wheel angle and yaw rate error and uses both the rear axle steering and torque vectoring is used at speeds above 40 kph. Gaussian distribution functions are used to switch from one controller to the other. The proposed control scheme is evaluated by using a validated TruckSim model in co-simulation with Simulink. Various standard events are used for testing. Two road friction coefficients are used, 0.35 and 0.85 µ at speeds between 40 and 100 kph. The proposed control system is able to greatly improve vehicle stability at high speeds and/or low friction and increase maneuverability at lower speeds and/or higher friction surfaces by decreasing vehicle response time delays and reducing steering wheel effort. A turning circle reduction of 30% was also obtained.