Development of an Omni-Directional Wheelchair Robot

Wheelchairs, as travel tools for the elderly and disabled, have enormous social demand. Difficult turning problems happen more often in the narrow and crowed space, so an omni-directional wheelchair robot, with dual differential driving units, is presented in this paper. First, dynamic model of the omni-directional mobile platform is established based on the analysis of a single differential unit. Then trajectory tracking control strategy is studied and trajectory tracking controller with stability and robustness is designed using adaptive sliding mode control with Lyapunov stability in consideration of disturbances. At last, smooth geometry path tracking is simulated. The theory and simulation results verify the effectiveness of the proposed control method and the controllability of the system.