Tip Growing Actuator with the Hose-Like Structure Aiming for Inspection on Narrow Terrain

This paper proposes a flexible hose-like fluid actuator to inspect narrow curved or bumpy terrain. The tip alone moves forward and the rest remains stationary, enabling the actuator to move smoothly without interfering with the outer environment – a concept based on the plant growth process. The actuator consists of multiple flexible flat tubes bent in the skin, whose bending point is involved in preventing fluid from passing through. The actuator can also steer the direction in which the tip lengthens, while the shape of the rest remains unchanged. Our Grow-hose-I prototype is 62 mm in diameter and grows at a maximum speed of 500 mm/s while producing a 45 N drive. The way of carrying a head unit equipped with a camera is discussed and feasibility of the actuator’s inspection on narrow terrain is demonstrated.