Wheelchairs have been widely used for walking disabled people. In order to operate a wheelchair to move straight or turn left/right, the user has to use his hands in order to control the motion of left and right wheels of the wheelchair. If the user cannot provide force to move the wheelchair, a helper is required to push/pull the wheelchair from the back. Electrical wheelchairs were developed in order that the users could operate the wheelchairs through control panel/joy stick. The wheelchairs can be used only on flat surfaces. Mobility between different levels are possible only through slope surfaces. The existing wheelchairs cannot move through steps; for example stairs, etc. Furthermore, the existing wheelchairs cannot plan the paths and cannot move to destination locations by themselves. They still require every
single commands from the users. Based on the above reasons, this research has been conducted in order to research and develop an autonomous mobile wheelchair which has an ability to move through steps for walking disabled people; for example, elderly people. The user is required only to provide the destination location, the mobile wheelchair will plan the paths and navigate itself to go to the destination. On the way to the destination, if there exist steps, the mobile wheelchair will climb the steps automatically. The developed mobile wheelchair consists of 16 degrees of freedom for all 4 legs. Each leg has a motor to drive 2 wheels in forward/backward direction, a motor to adjust the length of each leg, a motor to swing a link connecting the 2 driving wheels to climb up/down steps, and a motor to turn direction of each leg to have only a point of center of motion during turning. The results from experiments confirm that the developed mobile wheelchair can move in manual mode to follow commands from control panel/joystick and in automatic mode to follow commands from computer correctly with some small error of distance/angle.