Infrastructure facilities have been deteriorating and require a vast number of inspections conducted by skilled engineers. Robots for inspecting pipe and wall surfaces are required because of a shortage of skilled engineers. However, inspection robots are developed for a single environment, not multiple environments such as inside pipes and on walls. Therefore, we focus on both pipe and wall movement and investigate a miniaturization design method for flat-surface and in-pipe mobile robots. From various types of robots, we adopt a leg-type robot that can move regardless of the inspection environment. Furthermore, we combine a wire and a winding take-up mechanism to enable their legs to move up and down. This mechanism reduces the number of actuators used for their legs. We fabricate a compact prototype robot equipped with the devised leg mechanism. The size of robot is 175 mm length, 113 mm wide and 80 mm height. It was indicated that the robot could move forward and turn on a flat surface and forward in a pipe.

Organic abrasive machining (OAM) is a local machining method using organic abrasives and elastic rotating tool with a small-diameter, which is applicable to high-spatial-resolution figure correction of high-precision optical surfaces owing to its low machining rate and small spot size. In order to clarify the machining mechanism of OAM, the particle behavior between the tool and a transparent workpiece was observed in-situ using a microscopic observation system with a high-speed camera. First, the elastic contact area between the tool and workpiece surface was calculated based on Hertzian elastic contact theory, and the tool size for the observation experiment was determined. Next, a microscopic optical system was constructed and the velocity distribution of particles was obtained by in-situ observation. The particles moved linearly along the direction of tool rotation and the speed distribution had a narrow peak width at the center of the contact area. The ratio of particle speed to tool surface speed was independent of the tool rotation conditions (500 rpm to 2000 rpm). The particle speed distribution had a similar profile to the depth distribution of the stationary machining spot.

In recent years, five-axis controlled machining using barrel tools has been attracting attention from the perspective of improving machining efficiency. In five-axis controlled machining, tool center point control is used to compensate for the tool path. This process is effective for machining with ball end mills, where the distance between the tool center point (the command point) and the cutting point does not change. However, it is not compatible with barrel tools, where the distance between the command point and the machining point changes depending on the tool posture. The objective of this study is to develop a tool path interpolation method for barrel tools. By changing the reference point in interpolation from the tool center point to the cutting point, the tool path is corrected to meet the accuracy set by the user. The effectiveness of the proposed method was verified by generating tool paths using the proposed method and conducting machining simulations and experiments.