Mechanical Design Optimization of a Piping Inspection Robot

Abstract

The piping inspection for security or sealing checking is an important challenge when the internal diameter of the pipe is small with respect to its length. Some mechanisms using closed loops are able to generate contact forces and deployable structures. By using bio-inspired design, we present a mechanism which is able to move inside pipes by mimicking the motion of a caterpillar. The mechanism is composed of three sections, one for the motion and two with legs that are attached with the inner part of the pipe. A compliant mechanism is proposed to add mobility between the three sections of the robot in order to cross the singularity of the pipe. The results coming from a multi-objective optimization process is used to set the geometric and kinematic parameters of the mechanism taking into account the environmental and design constraints. A mechatronic system is proposed that uses industrial components namely DC motors, ball-screws and servo controllers which can be inserted in the pipe. For horizontal and vertical motions, the contact forces and the motor torques are computed to check the feasibility of the clamping. A prototype made at Laboratoire des Sciences du Numérique de Nantes (LS2N) is used to show the behavior of this concept for slow motions.