Anotace:
This work proposes new control approaches for tracking and motion planning of Unmanned Ground Vehicles (UGVs) that utilize skid steering system. This work proposes an energy based Variable Structure Control (VSC) scheme, in which two independent Sliding Control Surfaces (SCS)s are designed based on the system states. Particularly, the controller is designed based on the assessment and the minimization of the systems total energy by finding an explicit relation between the controller gains and the slope of the sliding surface. The work also discusses a new fuzzy potential approach for motion planning of UGV. The Fuzzy system generates an attractive force that pulls the UGV effectively toward a moving or stationary target, and a repulsive force, which is required to avoid any stationary or moving obstacles. Both, the VSC and the motion planning were validated by a nonlinear model of an Unmanned Tracked Robot (UTR) on different trajectories, and was compared with different control schemes. Simulation results show superiority of the proposed VSC over other methods with less control effort. Furthermore, the new motion planning controller proved its high capacity in producing a smooth and dynamic trajectory to allow an UGV to track a target and to avoid obstacles.