We are interested in investigating a new approach to robotic therapies wherein the patient would be given manual control over the exercise movements of the therapy.  Through the use of a teleoperated electromechanical robot, the patient could manipulate and assist their impaired limbs with their unaffected limbs.  This project is specifically aimed at rehabilitation for partial spinal cord injured subjects, where the impaired limbs are the legs and the unimpaired limbs are the hands/arms.  The ultimate rehabilitation goals do not involve completely removing the physical therapist from the therapy.  Rather, we propose a marriage of physical therapist expertise, robotic automation, and self-directed subject control over assistance in the rehabilitation process and training.  As a first step towards looking at self-assistance through teleoperation, we have chosen a simple task: manipulation of a virtual environment through a single axis at the feet (the primary ankle joint). 

<>The current state of the project is in hardware fine tuning and basic experiment design.  The basic hardware setup (pictured below) includes an actuated foot platform to interface with the subject’s feet; a hand controller through which the subject can interact with the feet (via the virtual environment); encoders to measure the positions of the hand, the foot actuator, and the foot platform; and a torque sensor at the feet.  Preliminary human subject tests on healthy volunteers have demonstrated that assistance provided by a hand controller to the feet improves performance in a tracking task compared to control by the feet alone.  Further tests on healthy human subjects are expected soon to test the effectiveness of using a self-assisting hand controller during a training stage for a lower limb task.  We hope to demonstrate that helping yourself to learn a task will improve performance even when the assistance is not used later.  This research will eventually progress to examine more complicated single axis ankle tasks, additional user actuation of the load through a hand manipulator, and ultimately studies involving subjects with spinal cord injury.

Lower Limb Haptic Device      

Research Project Member(s)

  Danek, Kari
Gillespie, R. Brent
Aldridge, J. Wayne
Ferris, D.P.
Grizzle, J.W.
Related Project(s)
  Upper Extremity Stroke Rehabilitation
Research Project Papers
A Dual Input Device for Self-Assisted
Control of a Virtual Pendulum
Project Sponsors
  University of Michigan Office of the
Vice President for Research and the National Science