Yukio Asari

Development of a model-based remote maintenance robot system. II. Environment measuring methods

For part I, see ibid., pp.1225-1230. The authors are developing a model-based remote maintenance robot system which autonomously carried out maintenance tasks in nuclear facilities, for example nuclear power plants and nuclear fusion reactors. Two measurements methods for the robot system are described: one is a laser range finder, and the other is a groping method for the target tasks of inserting a bolt and setting a nut. In the groping method, an arm with a bolt gropes on the flange surface, and a rapid change in the force signal is detected when the bolt tip comes across a hole. Position measurements are made by the joint angles in groping. Therefore, it has the same merit as direct teaching in industrial robots. The robot system has carried out inserting a bolt and setting a nut on a flange by using these methods.

Development of a model-based remote maintenance robot system. III. Task planner

For part II, see ibid., pp. 1231-1236. Introduces a task planner for the model-based remote maintenance robot system called TAROS (Toshiba Advanced Robot System). TAROSs task planner has a task knowledge database describing procedures for performing the desired tasks and an environmental knowledge database describing geometrical characteristics and arrangement data for the objects to be handled. These data are represented by frames. When the operator inputs a task command, the task planner generates robot control programs automatically by referring to the databases. In the task planning, even though objects position or orientation data in the environmental knowledge database include errors, suitable motions are selected from the task knowledge database according to the number of errors, and executed. Thus a desired task can be performed easily without making a detailed robot control program in which the objects position and orientation errors are taken into consideration. It was verified that the fastening and loosening operations for a nut and a flange bolt were performed autonomously by using the task planner of TAROS.