Path Tracking Control of Tracked Vehicle on Soft Cohesive Soil

Abstract

This paper deals with path tracking control of tracked vehicle on extremely soft cohesive soil. The dynamics of tracked vehicle is very complex and nonlinear because of the slippage of vehicle and the soil shearing. For the purpose of control of tracked vehicle we adopted simplified approaches. The vehicle is modeled as single-body vehicle. Two kinds of PD (Proportional-Differential) controllers are applied to the single-body vehicle model. First, a simple PD controller is designed for a differential-wheel drive vehicle model disregarding the slippage problem. The designed controller is implemented to the dynamic simulation software of the single-body vehicle model including the vehicle slippage on soft soil. The control error due to the disregard of slippage is investigated. The PD controller is modified to minimize the control error caused by disregard of soil slippage, which control the track velocities for optimum traction force from the soil resistance characteristics, i.e. shear stress vs. shear displacement. Through numerical simulations, it was shown that the control error is reduced by using the enhanced PD controller.