A powered wheel chair device comprises a motorized undercarriage and a support seat for supporting a wheelchair occupant. At least one support arm is located adjacent the seat. A controller is mounted on the arm, the controller including a joystick unit within reach of the occupant. The joystick is in communication with the motorized undercarriage for driving the undercarriage. The joystick includes an upstanding post with a collar, the collar having a periphery with a number of abutment regions located therealong. A number of actuators are provided, each movable from a storage position distal to the corresponding abutment region and a deployed position adjacent the corresponding abutment region. Each actuator is responsive to an obstacle detecting sensor near a corresponding peripheral region of the undercarriage.