Abstract
Ankle-foot orthosis (AFO) is a device widely prescribed for hemiplegic patients to assist their walking. Conventionally, AFOs are expected to have sufficiently high ankle joint stiffness to prevent involuntary plantar flexion during the swing phase. Such a high joint stiffness, however, disturbs the natural dorsal flexion due to the forward tilting of lower leg during the stance phase. The authors have proposed a concept of a variable stiffness AFO that is able to alter the ankle stiffness of AFO in accordance with the change of walking phase. This report discusses optimal shape design problems of three-dimensional monolithic AFO structure combining a stiffness switching mechanism with a joint structure of shoehorn AFO.
