Velocity control of a mine truck system using rationally scaled H ∞ control

This paper deals with the velocity control of a mine truck system. This truck system is composed of a motor, a cable and a truck and is used to convey miners in the mine. Due to the elasticity of the long cable, vibration of the truck occurs in operation which is uncomfortable and lowers the efficiency of the convey system. To design a feedback control system to suppress this vibration, we first establish a simplified 3-mass model from the given 7-mass model obtained experimentally. Then we use a descriptor form to pull out parameter perturbations independently. Since the parameter perturbations are nonlinear and time-varying, we first prove a sufficient condition for the robust performance of bounded structured nonlinear time-varying uncertain systems which is given by a scaled H_∞ norm with rational scales. Then we apply the rationally scaled H_∞ control to design a time-invariant controller. The results of simulations demonstrate effects of the control