Development of a Tele-operated Underwater Robotic System for maintaining a light-water type power reactor
The safety and reliability of nuclear power plants is very important. An inspection and maintenance of nuclear power plants should be achieved simultaneously. However, the limitation of a radiation exposure makes it difficult to work in nuclear power plants. Therefore, a tele-operated robotic system is very useful for inspecting and maintaining the components of nuclear power plants because it reduces the level of a radiation exposure to the human operators and it improves the reliability of an operation. A tele-operated underwater robotic system is needed for detecting and removing a loose part in a nuclear reactor vessel. A loose part, which can come from any failed component or an item left during a construction, refueling or maintenance like metallic parts, bolts, nuts and washers, affects the safety of a nuclear power plant. In this paper, an underwater robotic system is developed for inspecting the bottom of a nuclear reactor vessel and a reactor coolant system and also for removing some particles in them. In order to evaluate the performance of the developed underwater robotic system, an experiment was performed in a small swimming tank. In the experiments, the developed robotic system could inspect the state of the tank and remove some particles successfully
Development of a master controller for a 3-link dual-arm underwater robot
Master-slave system is a vital technique for controlling robot motions. An intuitive master controller enables precise and easy control of robot, especially for underwater robotics applications. Most of the commercially available master-slave systems are very complex and expensive, and operators need to receive extensive training before being able to correctly operate the robot. This paper addresses these problems by introducing a simple and intuitive master controller for an experimental semi-autonomous underwater vehicle equipped with 3-link dual-arm. The master controller includes a vehicle main master controller and two units of 3-link manipulator master controller. Moreover, each end-tip of the manipulator master controller is attached with a vehicle sub-master controller that consists of a joystick and tactile switches. These sub-master controllers are designed to control the position and attitude of the vehicle. The ability to simultaneously control two units of 3-link dual-arm and the position and attitude of the vehicle is the uniqueness of the proposed controller. In this work, the design of the developed master controller and the structure of a unilateral master-slave system are presented. The usefulness of the master controller is verified through experiment on controlling an actual dual-arm underwater robot to catch a target object in underwater environment.
Problems of a centralised department in a decentralised mental hospital.
Abstract This paper deals with some of the issues and problems which arose in a state mental hospital, when in the course of becoming a more community-oriented facility, the hospital decentralized its clinical structure into geographically-based treatment units while retaining a centralized nursing department administration. The effects of unitization and a subsequent attempt to reoganize the nursing department on both the character of professional roles and the integration of parts of the hospital are discussed within the context of an open-systems conceptual model of hospital organization.