The proposed project aims to develop a compact and light-weight robotic prosthesis, with the objective of significantly enhancing the health and life quality of the 400,000 transtibial (i.e., below-knee, BK) amputees in the United States. In human locomotion, the ankle plays an important energetic role, and supplies substantially more positive power than the knee and hip. However, in the majority of existing BK prostheses, the prosthetic ankle joints are energetic passive, only storing and dissipating energy in use. The inability to generate power significantly impairs the prosthesis'capability of restoring the locomotive functions for the amputee user. Clinical studies indicate:that amputees wearing passive BK prostheses exhibit asymmetric gait kinematics and expend significantly more energy in comparison with healthy subjects. To address this issue, the investigators will explore an innovative chemo-fluidic sleeve muscle actuation system to power the BK prostheses. Two key elements form the basis of this new system: (1) Sleeve muscle actuator, an innovative muscle actuator with very high power density (at least ten times higher than DC motor);(2) Highenergy- density pneumatic supply, which is able to store a large amount of energy within a highly compact package. With this high-performance actuation system, the prosthesis is anticipated to meet the demanding power requirements imposed by the human locomotion, while minimizing the prosthesis weight and height to enlarge the amputee population that can benefit from the new powered BK prosthesis. The breakthrough in actuation technology will be complemented with a novel intent recognition and motion control algorithm, which is anticipated to provide the user's desired motion in a highly interactive manner. This control system identifies the desired locomotive pattern based on the user's inferred motion intent, and generates the desired joint torque command though ah impedance-based motion controller that enables physical interaction between the user and the prosthesis. The robotic prosthesis and the corresponding control system will be further tested to characterize its biomechanical benefits relative to state-of-the-art passive BK prostheses.

Public Health Relevance

This project aims to develop a compact and light-weight robotic prosthesis, which will benefit the population of 400,000 transtibial (i.e., below-knee, BK) amputees in the US. Utilizing an innovative chemo-fluidic sleeve muscle actuation approach, this prosthesis will enable active power output to support the user's locomotion, and thus provide significant health benefit to the BK amputee relative to existing passive prostheses.

National Institute of Health (NIH)
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZEB1-OSR-A (M1))
Program Officer
Quatrano, Louis A
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Alabama in Tuscaloosa
Engineering (All Types)
Schools of Engineering
United States
Zip Code
Zheng, Hao; Wu, Molei; Shen, Xiangrong (2016) Pneumatic Variable Series Elastic Actuator. J Dyn Syst Meas Control 138:0810111-8101110
Shultz, Amanda H; Lawson, Brian E; Goldfarb, Michael (2016) Variable Cadence Walking and Ground Adaptive Standing With a Powered Ankle Prosthesis. IEEE Trans Neural Syst Rehabil Eng 24:495-505
Zheng, Hao; Shen, Xiangrong (2015) Design and Control of a Pneumatically Actuated Transtibial Prosthesis. J Bionic Eng 12:217-226
Shultz, Amanda H; Lawson, Brian E; Goldfarb, Michael (2015) Walking on uneven terrain with a powered ankle prosthesis: A preliminary assessment. Conf Proc IEEE Eng Med Biol Soc 2015:5299-302
Shultz, Amanda H; Mitchell, Jason E; Truex, Don et al. (2014) A walking controller for a powered ankle prosthesis. Conf Proc IEEE Eng Med Biol Soc 2014:6203-6
Zheng, Hao; Shen, Xiangrong (2013) Double-Acting Sleeve Muscle Actuator for Bio-Robotic Systems. Actuators 2:129-144
Zheng, Hao; Shen, Xiangrong (2013) Sleeve muscle actuator and its application in transtibial prostheses. IEEE Int Conf Rehabil Robot 2013:6650444