Mobility Assistive Robots for Disabled Patients

2.1 Background Wheelchairs are one of the most important mobility aids for disabled patients and elders. In general, wheelchairs are categorized as manual and powered types. From the viewpoints of movement behaviours, the powered wheelchair can be regarded as a mobile robot (Asai, 2001) if additional environmental sensing components are built and an intelligent motion controller is included. Therefore, robotic wheelchairs (Luo et al., 1999) are proposed integrating novel sensing and intelligent control technologies to improve the convenience and comfort of mobility assistance. In general, robotic wheelchairs integrate the sensing, intelligent computing, and communication technologies to improve the autonomy when compared to the conventional powered wheelchairs. The assistive technologies resolve the problems of conventional powered wheelchairs of: 1. Stable velocity control of wheels in terms of feedback motion control system. 2. Comfortable wheelchair driving in terms of velocity adjustment of wheels for various degrees of turning. 3. Collision avoidance of wheelchairs for approaching still and moving objects or person.