Towards the control of a powered orthosis for people with muscular dystrophy

The paper describes the development of a passive/active orthosis for people with limited anti-gravity strength in their arms. This is symptomatic of conditions such as muscular dystrophy and spinal muscular atrophy. A passive orthosis was designed and developed using linear elastic elements. The system is being tested with children with disabilities and preliminary results are encouraging. An RT200 robot was also used as a test-bed for an active orthosis. The robot was instrumented with a six-axis force/torque sensor at the end-effector. The force acted as the input to the robot. The robot kinematics and dynamics were modelled. A number of control schemes were implemented on the test-bed including force proportional to velocity and acceleration; these schemes were evaluated with two subjects.