ManipuRailer: A Long-reach Robotic Arm Comprising Linear and Rotational Joints Equipped with Multiple Rails for Deploying Robots to Hard-to-Access Locations

Abstract

The aging of transportation infrastructure and large production facilities has become a serious problem, leading to an increased demand for robotic work support. To meet this demand, robots need to be installed in environments that are difficult to access due to a lack of footholds, such as high and narrow places, but this is difficult. To solve this problem, we have developed ``ManipuRailer'', a robot arm comprising linear and rotational joints and equipped with multiple rails for robot locomotion and support. A scale model is fabricated, and the followings are clarified through experiments. To prevent torsional deformation, it is effective to design a symmetrical rail structure with all arm links and joints placed on a single plane. The following three design and operational innovations are effective in reducing the driving torque of long reaching arm. (a1) The parts of the sliding mechanism should be installed at the leading edge of the rotating part. (a2) The pully and timing belt should be placed so that the sprocket and tooth surface are near the restraining surface by the guide rail. (b1) The center of gravity of the rotating body is shifted by the rail sliding mechanism. These measures shorten the distance between the rail and the axis of rotation and reduce the load moment.