An EMG-Controlled Device Managing Transition From Passive to Active Exercise in the Acute Rehabilitation of the Ankle Joint

The capacity of flexing one’s ankle is an indispensible segment of gait re-learning, as imbalance, wrong compensatory use of other joints and risk of falling may depend on the so-called drop-foot. The rehabilitation of ankle dorsiflexion may be achieved through active exercising of the relevant musculature (especially tibialis anterior, TA). This can be troublesome for patients affected by weakness and flaccid paresis. Thus, as needs evolve during patient’s improvements, a therapeutic device should be able to guide and sustain gradual recovery by providing commensurate aid. This includes exploiting even initial attempts at voluntary motion and turn those into effective workout. This paper presents an active orthosis powered by two rotary actuators containing shape memory alloy (SMA) wire that promote passive ankle dorsiflexion. A computer routine that analyses the electromyographic (sEMG) signal from TA muscle is used to control the orthosis and trigger its activation when appropriate sEMG signal is recorded.