Development of Hydraulic Drive Drilling Robot with 4-DOF Tool for In-Pipe Repair – Mechanical Design of New Tool –

Lately,many developed countries see their sewer pipes getting increasingly aged. They try to extend the life of aging pipes by using teleoperated sewer robots to repair them as buried in the ground rather than replacing them by largescale digging work. Currently available robots, however, have tools with small DOF (Degrees Of Freedom) to do complex work such as drilling, cutting, and grinding. They also have too heavy oilostatic cables to be self-propelling. To cope with these problems, we intend to develop a new type of sewer robots that can be self-propelling by built-in cylinder-type hydraulic power source and are equipped with multiple-DOF tool driven by hydraulic cylinders in parallel links. In this paper, we propose a 4-DOF parallel link type mechanism for the tool that have wide reachable areas and no singular points. The proposed mechanism is so designed as to be able to retain high stiffness in the predetermined reachable areas as required for work inside pipes.