FAULT DIAGNOSIS AND FAULT-TOLERANT CONTROL OF A JOYSTICK CONTROLLED WHEELCHAIR

Abstract

This paper presents a method of fault diagnosis and fault-tolerant control for a joystick controlled wheelchair. The hard faults of sensors and actuators in two drive/steering units of the wheelchair are handled. A fault diagnosis of the sensors and actuators is achieved based on the interacting multiple-model (IMM) estimator. To make better fault decision, mode probability averaging and heuristic decision-making rule are incorporated into the IMM based algorithm. A fault-tolerant control system, which allows a safe motion of the non-holonomic wheelchair even though the drive and steering units have partially failed, is designed based on the Ackerman geometry. Experimental results validate the proposed method.