7功能水下机械手介绍

underwater vehicle, a tethered ROV, equipped with an underwater camera system[3]. To develop a hydraulic underwater manipulator, which is different from manipulators operated on land in many technologies, including manufacture, process, seal, power supply, communication, controller design, and so on. Especially, for an underwater manipulator, it needs water seal under high pressure and communication with long distance. In [3-7], their works were focused on controller design. Dynamics of underwater manipulator were analysed in [8,9]. However, an underwater manipulator has not been systemically studied in published literatures. Some components, such as pressure compensator, communication devices and underwater valve pack, are necessary for a underwater manipulator. Without those components, an underwater manipulator can not work well, though it has a good controller. In this paper, an underwater manipulator is designed and developed for grasping an underwater object. The manipulator which is operated by a master-slave style mainly consists of a master controller, a slave arm, a valve pack, a connection box, hydraulic power unit and a pressure compensator. It is driven by hydraulic power with seven functions, high lift-to-weight ratio, large operating envelop, quick and easy diagnostics. What's more, the developed underwater manipulator is dexterous, accurate and reliable.
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Abstract - A 7-function underwater manipulator which is teleoperated by master-slave type is systemically developed. It is mainly comprised of master controller, connection box, slave arm, pressure compensator, valve pack and hydraulic power unit. The slave arm is operated by the master arm, which is fixed on the master controller used to operate, configure, and diagnose the manipulator system and is a miniature replica of the slave arm. The movement of the smaller master arm is replicated by the larger slave arm. The pressure compensator provides hydraulic pressure compensation such that the compensated pressure is slightly higher than the ambient water pressure. A closed position loop is utilized to the control of each slave arm function except the jaw, integrating fault and error diagnosis. The valve pack, communication and power supply are also analyzed. The developed underwater manipulator is dexterous, accurate and reliable. Index Terms - Underwater manipulator. Maser-slave type operation. Position control. Pressure compensation.
I. INTRODUCTION
Oceans is a familiar environment for us. It covers about two-thirds of the earth and has a great effect on the future existence of all human beings. About 37% of the world's population lives within 100 km of the ocean. The ocean is generally overlooked as we focus our attention on land and atmospheric issues; we have not been able to explore the full depths of the ocean and its abundant living and non-living resources. Oceans are an attractive environment because of abundant resources,பைடு நூலகம்energy, space. For example, it is estimated that there are about 2,000 billion tons of manganese nodules on the floor of the Pacific Ocean near the Hawaiian Islands[I,2]. However, the extreme conditions such as high water pressure, invisibility and non-oxygen become great barrier to access directly. Underwater robots are expected and developed as efficient tools for the operation instead of human beings. Underwater robots can help us better understand marine and other environmental issues, protect the ocean resources of the earth from pollution, and efficiently utilize them for human welfare[l]. Robotic manipulators, mounted on remotely operated vehicles (ROVs), have an important role to play in a number of shallow and deep water missions for marine science, oil and gas, survey, exploration, exploitation and military applications. Current underwater robotic systems typically comprise one or more manipulators mounted on the front of an
Jianjun Yao, Liquan Wang, Peng Jia and Zhuo Wang
College ofMechanical and Electrical Engineering Harbin Engineering University Harbin, Heilongjiang Province, China
II. SYSTEM OVERVIEW
The manipulator is a hydraulically powered, remotely controlled manipulator system which is operated in a masterslave style by an operator on the surface vessel. The whole configuration of the underwater manipulator is shown in Fig.l. The system is mainly comprised of a master controller, a slave arm mounted on a ROV, a valve pack, a pressure compensator, a hydraulic power unit and a connection box. The slave arm has six degree of freedoms (DOFs), tipped with a jaw tool to grasp and manipulate objects. Seven functions are composed of six DOFs and the jaw motion. The motion of the slave arm is controlled by the master arm. The valve pack serves as a hub for the control and distribution of hydraulic fluid to the slave arm, the distribution of electrical power to slave arm electrical assemblies, the routing and processing of control telemetry between the master controller and slave arm.