Kinematics, control and redundancy resolution of a 9-DoF wheelchair-mounted robotic arm system for ADL tasks

A wheelchair-mounted robotic arm (WMRA) system was designed and built to meet the needs of mobility-impaired persons with limitations of upper extremities, and to exceed the capabilities of current devices of this type. The control of this 9-DoF system expands on the conventional control methods and combines the 7-DoF robotic arm control with the 2-DoF power wheelchair control. The 3-degrees of redundancy are optimized to effectively perform activities of daily living (ADLs) and overcome singularities, joint limits and some workspace limitations. The control system is designed for teleoperated or autonomous coordinated Cartesian control, and it offers expandability for future research. Different user-interface devices, including a Brain Computer Interface (BCI) were integrated to the control of the WMRA system. Testing and data collection were performed on human subjects. Various optimized control methods and test results are presented in this paper.