A study on an independent steering & driving control algorithm for 6WS/6WD vehicles

Skid-steered vehicles are favored for military use in off-road operations because of their high maneuverability and mobility on extreme terrains and obstacles. There is a trend towards transforming steered tracked vehicles to skid-steered wheel vehicles for high speed at the expense of reduced mobility. Skid-steered vehicles turn by generating different longitudinal forces at the tires due to the application of different torques to the wheels on the opposite side of the vehicle. Conventional vehicles, however, cannot generate an opposite driving force at each side wheel. Using an independent steering and driving system, six-wheel vehicles can show better performance than conventional vehicles. Hybrid steering is a combination of skid steering in the load velocity and the steered wheel system at high speed. This steering enhances maneuverability under low speed and stability at high speed. This paper describes a 6WS/6WD vehicle for hybrid steering in three parts: the Vehicle Model, the Control Algorithm for Hybrid Steering, and a Simulation. First, the vehicle model is an application of the TruckSim software for 6WS and 6WD. Second, the hybrid steering control algorithm describes the optimum tire force distribution method for energy savings. The last is simulation and verification.