Nonlinear straight path tracking control for an articulated steering type vehicle

Autonomous control of an articulated steering type vehicle such as a wheel loader, which is usually used at surface mining fields to load mineral resources and rocks, is highly expected for operation cost reduction. A wheel loader is one of heavy machines which is also used for snow removing and/or loading operation at construction fields because of its high mobility. Its steering system is articulated steering and the rear wheels follow tracks where the front wheels have traveled. We have formulated nonlinear state equations using two velocity constraints. A nonlinear state-feedback controller is designed using the exact linearization method. Simulation and experimental results show that an articulated steering type vehicle can follow a straight line with the proposed feedback controller.