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.
To develop a mining system for deep-sea mineral resources like manganese nodules is a challenging task in ocean engineering. Mining system is composed of collecting system, lifting system and surface vessel. Self propelled vehicle aims at proper positioning of the collecting system along the mining tracks on deep seafloor. Brink et al. (1981) presented a control concept for the combined shippipe- buffer system. Generally, tracked vehicles are used in military, agricultural and recreational applications where terrain conditions are improper or unpredictable. Tracked vehicles are better than wheeled vehicles due to the larger contact area of tracks providing better floatation and traction at various ground conditions. Hence, tracked vehicle has been chosen for the mobility on the soft and cohesive seabed soil.
