Static analysis of powered low-back orthosis driven by thin pneumatic artificial muscles considering body surface deformation

Low back pain due to physical loading at work is reported as severe problems in many fields, and many scientists and technologists are working on power assistive orthoses to solve these problems. Thin pneumatic McKibben Artificial muscle has features of thin, lightweight, and flexible, and it could be used as yarns of making clothes. Therefore, it is one of the best actuators, among existing ones, to design a cloth-like power assisting orthosis which operates actively. When designing such devices, it is preferred to maximize the efficiency of the assistive power, and minimize the load applied to one's own body. We analyzed a specific motion lifting a load by introducing a stick model, and optimized attaching positions and forces of the actuators considering the body surface deformation. The optimization indicated very acceptable results that locating the artificial muscles from the upper back to the knee offers the best result under the defined conditions in the analysis. These results indicated that proposed model can be helpful for designing clothlike powered orthoses.