Development of walking assist device by regenerating the upper body position energy from vertical oscillation of the upper body

Legged locomotion is high environmental adaptability by the effect of ability to choose landing positions freely, but low transfer efficiency. Because, the output is consumed by supporting upper body. In this paper, we propose a passive walking assist device with two air cylinders and surge tanks. This new device has three advantages in comparison with conventional devices. (1): The proposed device can effectively assist than conventional devices that are arranged spring element series to leg, because it has a twist arranged spring in parallel without interfering swing motions. (2): The weight is very light (1.5kg) and assist force is powerful (about 20̃40 N / leg), using the system it runs by air. (3): The assist force is not from the electricity, from the loss of walking. Demonstrating these effects, we create the device and measured feelings and assist powers, Feeling are measured throughout the walking motion and bends by each load condition. Assist power are measured by a device that reproduces the walk. From result of this, it is expected that leg power can be assisted effectively.