Development of Torque Control Algorithm for 6x6 Skid Steering Vehicle

Abstract

Skid steering vehicles have good maneuverability and mobility on rough and extreme terrains. In skid steering vehicle all the wheels are non-steerable and the vehicle is turned as a result of the application of differential torque to wheels on opposite sides. The use of electric motors in each wheel instead of mechanical drives is more advantageous regarding performance. The electric motor response time is very short and also the torque can be known from motor current. Moreover using In-Wheel-Motor each wheel can be control independently. In this study first we modeled the Six Wheel Skid Steering Vehicle having 6 in-wheel motors then we proposed Torque Control Algorithm. Two PID controllers with filters are used to achieve the desired velocity and desired yaw rate. This torque control algorithm determines the torque commands for each wheel based on the desired yaw rate and desired velocity. The slip ratio controller is applied to each wheel independently as minor loop to prevent slipping. This algorithm is applied to Driver-In-Loop mode using the developed 6x6 model and simulations are carried out using MATLAB Simulink®. These results show that this control algorithm can be use effectively in controlling the skid steering vehicle on different road conditions.