Passively adaptable wall climbing robot in narrow space

This paper presents a novel wall climbing robot for a narrow space that is not accessible for humans, such as a sewer pipe and small gaps between buildings. The proposed robot consists of two driving parts and a pantograph between them that generates a pushing force against the walls to prevent the robot from falling down. Two different kinds of springs are installed on the pantograph in order to provide certain amount of the pushing force. The proposed mechanism can passively adapt to the changes in the interwall distance with a constant pushing force to achieve a smooth movement. The experimental results show that the proposed robot can work reliably and safely in different types of narrow spaces between walls.