Parallel-link robot for pipe inspection

In air conditioning equipment, it is very important to diagnose in-pipe corrosion for preventing various troubles such as water leakage, deterioration of performance and so on. We have been developing a pipe diagnostic system for decreasing the time and workload of the inspection and improving the accuracy of the diagnosis, especially a pipe thickness measuring robot with ultrasonic probe which can conduct inspections from outside of the pipe. Existing inspection robots using ultrasonic probes are not suitable for measuring the entire surface of pipes because they use rails fixed to the pipe for scanning, or even if they have unfixed rails and can move along the pipe, they cannot measure joints such as elbow. Therefore, we propose a new pipe inspection robot with parallel-link mechanism, which has a circular rail for scanning the ultrasonic probe, a manipulator for setting the rail and a mobile robot for moving along the pipes. The manipulator and the mobile robot are constructed with the parallel-link mechanism. The feature of this robot is that it can pass elbows and so can measure every section of them. In this paper, we describe the robot mechanism and control method, and the results of experiments with the robot.