Study Of Traction Coordinating And Path Following Control Method For Lunar Rover

Because of the rough and complex environment covered with soft, fine dust-like lunar regolith, which the lunar rover traverses, the mismatch of motion state among wheels happens very easily. The stress generated in the suspension, mechanical wear and power consumption increase because of the mismatch motion state among wheels. So the Traction Coordinating control strategy of lunar rover becomes one of the technical problems needs to resolve.Because of low-gravity environment of the lunar surface makes difficult to simulate lunar soil environment on the ground, the3-D simulation model of lunar rover with rocker-bogie based on the three-dimensional visualization of dynamic simulation software ADAMS. The traction coordinating controller is designed to optimize the wheel’s traction force taking the average slip ratio of each wheel as the control variables. The velocity of the rover and the influence of the normal force on the traction force of wheels were integrated into the proposed controller. Simulation results for a wheeled rover traversing moon-like terrain slope and ditch demonstrated that the effectiveness of the control algorithm and the mobility improvement.In order to travel following with the planning trajectories and reach the destination, the vertical and horizontal tracking errors of lunar rover should be considered precise. So the method of path following control based on slip ratio compensation is designed after controling the wheels’ traction, avoiding the frequent turn of wheels to enhance the life of steering motors on the one hand and ensuring the lateral tracking accuracy on the basis of the vertical accuracy control the other hand. By analyzing the kinematics and traction system identification to build the state-space model of the system, path following is controlled by optimal controller. The observability and controllability of the system are controlled too.Finally, co-simulations between ADAMS and MATLAB/Simulink are carried out and the simulation results demonstrate that the effectiveness of reducing slip ratios’differences on the basis of realizing the path following. The proposed algorithms in this paper made the motion of lunar rover more flexible and harmonious because of lower power consumption and improved mobility.