Development of rehabilitation system for the upper limbs in a NEDO project

Movements of the upper limbs are complicated, various and indispensable for daily activities. It therefore is important for the aged to exercise to keep their upper limb function. When something is wrong with the upper limb function because of disease or disorder, rehabilitation along with medical treatment is needed to recover function. Application of robotics and virtual reality technology makes possible for new training methods and exercises on upper limb rehabilitation and for quantitative evaluations to enhance the qualitative effect of training. However, rehabilitation systems applying training within a three-dimensional to upper limbs have not been in practical use. The authors have involved in a project managed by NEDO (New Energy and Industrial Technology Development Organization as a semi-governmental organization under the Ministry of Economy, Trade and Industry, Japan), "Rehabilitation System for the Upper Limbs and Lower Limbs", and developed a 3-DOF exercise machine for upper limb (EMUL). In this paper, the authors report on development of EMUL which can be use as a motion guide robot or a force display device. Particularly, mechanical structure safety kept by actuators using ER fluid is mentioned.