Ankle training robot force visualization for eccentric contraction training

Abstract

This paper describes the development of an ankle training robot force visualization for eccentric contraction training. In the mechanism of walking, the eccentric contraction of the tibialis anterior muscle plays an important part in the phase between heel-strike and foot-flat as a shock absorber. However, the eccentric contraction has not been reported in previous research on ankle rehabilitation robots, despite its importance. In addition, traditional training methods both unaided and with tubing have difficulty making the training load constant. Hence, this study proposes a system that uses visual feedback of the forces to help the patient keep the training load constant. We present an estimation method for the lower extremity posture and torques. We also experimentally subject compared output force with and without the use of visual feedback.The results show that the system is able to make the training load constant. Furthermore, frequency analysis using the fast Fourier transfer (FFT) of the force information measured during training and passive motion shows that the robot is capable of detecting unwanted vibrations.