A joystick car drive system with seating in a wheelchair

This paper presents a joystick car drive system for a handicapped person. The joystick drive system enables handicapped person to drive a car by his/her single hand with seating in an electric wheelchair. 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 disabilities such as no enough force nor limited movable area of their arms together with disabilities in legs, can drive a car by oneself. Additionally, a wheelchair driver does not have to change seat from a wheelchair to a car seat. Since a developed van equips with a lift on the back, a wheelchair user can access to the driver's position with propelling a wheelchair inside of a van. For maintaining driving safety of a van in case of system fault, gas and brake pedals are physically moved by a mechanical linkage which is connected to a joystick lever. Therefore a van can be stopped by manual operation in any case. A steering wheel is turned by an electric motor which is controlled by a micro-computer system. A steering angle is PID controlled to track the reference angle given by a joystick. To realize the joystick drive system with seating a wheelchair, 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 human drivers. 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 of a real van and tested the realizability of the proposed joystick controlled car-wheelchair mobile system.