A joystick car drive system for wheelchair users

This paper presents a joystick car drive system for wheelchair users with severe handicaps. The joystick drive system enables handicapped person to drive a car with his/her single hand. The joystick operation in back and force direction controls acceleration or deceleration of a car while that in left and right direction turns a steering wheel. Therefore a person, who has some disabilities such as no enough arm force nor moving their arms in wide area together with disabilities in legs, can drive a car by oneself. For maintaining safety of a car in case of system fault, gas and brake pedals are physically moved by mechanical linkage which is connected to a joystick lever. Therefore a car can be stopped by manual operation in any case. A steering wheel is driven by a electric motor which is controlled by a micro-computer based motor driver. A steering angle is PID controlled by feedback control to track the reference angle given by a joystick. To realize the joystick car drive system, we design a steering drive mechanism which includes a DC motor, a magnetic clutch, and a potentiometer for steering angle detection, and transmission gears. Most of cars manufactured in these days equip with power steering systems which reduce steering operation power of a human driver. Therefore the system can utilize the power steering system for realizing the joystick car drive system with minimum capacity of a motor. The prototype mechanism is mounted on a car cockpit simulator and a realizability of the proposed joystick car drive system is tested by wheelchair users.