Abstract

Arm weight support increases range of motion and breaks abnormal movement patterns such as flexion synergy. Conventional tools for arm weight support are simple devices to be used at homes but continuous feedback and monitoring is not possible. Rehabilitation robots could be a potential solution but are very complex for home use. Thus, a hybrid system which is simple and provides feedback is needed to increase adherence to home therapy. The kinematic design and optimization of link lengths of one such hybrid robot-Motorized Arm Support (MARS), is proposed in this study. Two kinematic chains of MARS (4 DOF and 5 DOF MARS) were considered for supporting planar reaching movements of the arm along with shoulder flexion/ extension. The 5 DOF MARS reaches 4.4% more work area of the arm but increases the complexity of the system as it requires additional mechanical elements such as dampers to prevent impact forces at the arm. Thus, to keep the system simple, the small loss in work area is considered acceptable and the 4 DOF kinematic chain of MARS is chosen for further development.