Design and prototyping of a novel lightweight walking assist wear using PVC gel soft actuators

Innovative technologies are needed to support the daily activities of elderly people and to lighten the heavy burden of nursing in the aging society. And the technology of soft actuators should be one of the key issues for developing such technologies. We have developed a soft actuator using the plasticized polyvinyl chloride (PVC) gel which has many positive characteristics, such as being soft and lightweight, having a stable actuation in the air with a high output, a notable response rate, a low power consumption and no noise. In this study, we applied the PVC gel soft actuators to develop a novel lightweight walking assist wear for a daily life support of the elderly people. We used the contraction and expansion movement and generation force of the actuators to provide the assistance. And we used some force sensors integrated in the insoles to detect the gait changes during walking. A prototype was designed, fabricated and the characteristics were evaluated in this paper. The prototype has a mass of about 0.6 kg, with an output force about 94 N (corresponding to torque of over 10% of the nominal biological moment at the hip during unloaded walking), a power consumption of about 1.6 W. The proposed assist wear has the advantages of a simple structure, light weight, high flexibility and easy to put on and take off which indicate the feasibility to use for a daily life walking assistance.