1. Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235
2. Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235
3. Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235; Department of Physical Medicine and Rehabilitation, Vanderbilt University, Nashville, TN 37235
4. Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235; Department of Physical Medicine and Rehabilitation, Vanderbilt University, Nashville, TN 37235; Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235