Successful Joint Development of Electromechanical Manipulator with High Radiation Resistance

Manipulator

Mitsui E&S Machinery Co., Ltd. (CEO: Ryoichi Oka) and Wälischmiller Engineering GmbH of Germany (MD:Claudia Reich)*1 have jointly developed an electromechanical manipulator*2 with more than twice the resistance to radiation of conventional units. It is the world's first manipulator to apply sensorless control technology for decommissioning work.

This development project was aimed at achieving target values for radiation resistance of manipulators for decommissioning Fukushima Daiichi Nuclear Power Station (Dose rate: 10kGy/h, Total dose: 2MGy). After around three years of development efforts, Mitsui E&S Machinery and Wälischmiller Engineering succeeded in improving the radiation resistance of all the parts of the electromechanical manipulator and developing a control system that does not require a position sensor (sensorless control system). They achieved twice the radiation resistance(2MGy) of current manipulators (1MGy) and reduced the number of wires needed for each unit by half.

The radiation resistance of the developed manipulator has been confirmed by irradiating all its parts with an equal amount of gamma rays as the target value at an irradiation facility and then testing them to check that their insulation properties, mechanical strength, and other properties have not deteriorated.

As a result of the successful development, the frequency of manipulator replacement will be reduced by half and the number of wires needed will also be reduced by half.
This will also enable a significant reduction in secondary waste*3 generation.

In addition, while there are several types of manipulators -- hydraulic type (such as oil hydraulic and water hydraulic ones) and electromechanical ones --, the developed electromechanical manipulator comes with the following features, which allow it to be used for a range of purposes in decommissioning work and permit the flexible change of the specifications.

• Wide operating range: The arm joints have no parts which restrict it's rotation like as piping or cabling.


• Modularization: The upper arm, lower arm, hand, and other parts are modularized, permitting changes in the arm length and other specifications in accordance with the purpose of use. The remote attachment and removal of each module is also possible.
• Use in special environments: There are also lineups for underwater (IP68) or made explosion-proof (Zone 0).

The prototype of this electromechanical manipulator is currently being produced. It is planned to be revealed at the Tamano Works Machinery Factory of Mitsui E&S Machinery at the end of September 2018.

Mitsui E&S Machinery Co., Ltd. and Wälischmiller Engineering GmbH will continue to propose a range of robot systems with special specifications to contribute to decommissioning projects.

*1: Established in 1946, Wälischmiller Engineering GmbH is a German manufacturer that specializes in manipulators for nuclear industries. It has achieved global acclaim. The company has delivered approximately 3,000 units (148 electromechanical manipulators and more than 2,800 mechanical manipulators) to customers in dozens of countries around the world. In Japan, the company has been in a partnership with Mitsui E&S Machinery Co., Ltd. in the field of manipulators for nuclear power facilities for approximately 30 years, having delivered more than 220 units (11 electromechanical manipulators and more than 210 mechanical manipulators).

*2: A manipulator means an arm-shaped robot. It is used for work in environments where humans cannot work, such as under high temperature, high pressure, and high radiation.
There are mechanical, electromechanical, and hydraulic units (such as oil hydraulic and water hydraulic ones). Wälischmiller Engineering is one of the world's leading specialized manufacturers of mechanical and electromechanical manipulators.

*3: Secondary waste is contaminated waste generated from decommissioning work.
A power manipulator that has reached its end of life also becomes the part of contaminated waste.