A study on autonomous maintenance robot. (7th Report, Mechanism of Mark IV and its actuator characteristics).

Abstract

This paper deals with the new mechanism of a new maintenance robot, Mark IV, following the previous reports on pipeline inspection and maintenance robots of Mark I, II, and III. The Mark IV has a mechasism capable of inspecting surfaces of storage tanks as well as pipeline outer surfaces, which is another capability of the maintenance robots, different from the previous ones. The main features of Mark IV are as follows, (i) The robot has a multijoint structure, so that it has better adaptability to the curvartures of pipelines and storage tanks. (ii) The joint of the robot has SMA actuators to make the robot lighter in weight. Some actuator shape characteristics are also examined for the robot structure and control. (iii) The robot has suckers at both ends, so that the robot can climb up along the wall from the ground. (iv) A robot with the inch worm mechanisms has many functional motions, such that it can pass over flanges and T-joints, and transfer to adjacent pipelines with a wider range of pipe diameters. (v) A control method is given for the mobile motion control. Thus, the functional level of the maintenance robot has been greatly improved by the introduction of the Mark IV robot.