High frequency reject MRACS for smooth joint movement

A model reference adaptive control system (MRACS) is proposed for reduction of oscillatory joint movement frequently observed in closed-loop functional neuromuscular stimulation (FNS). The modified methods presented are as follows: (1) the transfer function of the musculoskeletal system is identified from high-frequency rejected input-output signals; (2) the controller is modified to reject the high-frequency components from the feedback loop; and (3) coactivation of the agonist and antagonist is applied. Joint angle control of knee and ankle are carried out on normal subjects and paraplegic patients. An obvious smoothness improvement is attained in comparison to a conventional MRACS.<>