Press Information

MHI Develops "MHI-Super Giraffe (MARS-C)":
Remote-controlled Robot Capable of Work at Heights Up to 8 Meters
-- Robot Arm at Top of Telescopic Ladder Accommodates Diverse Needs --

No.1625
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Tokyo, February 20, 2013 - Mitsubishi Heavy Industries, Ltd. (MHI) has developed a remote-controlled robot, dubbed the "MHI-Super Giraffe (MARS-C)*1, capable of working at heights up to 8 meters (m) and moving freely in areas inaccessible by humans like highly radioactive environments. By changing the robot arm and/or tool attached at the arm end, the MARS-C can perform various tasks including valve opening/closing and radioactive decontamination work. For this robot MHI adopted a modular design concept applicable to each movement or work mechanism. To accelerate the achievement of even more advanced robot capabilities in the future, the company intends to disclose its technical data pertaining to the MARS-C's various connecting parts in order to enable the development of modules by other companies, so that going forward MHI itself can develop new modules incorporating such externally created technologies.

[MHI
The MARS-C was developed as a "Research and Development Project for an Unmanned Disaster Response System" consigned by the New Energy and Industrial Technology Development Organization (NEDO), with the aim of accommodating various tasks needing to be performed at the Fukushima Daiichi Nuclear Power Station operated by Tokyo Electric Power Company: for example, valve opening/closing, decontamination work, leakage detection and identification, cutting, etc. The robot is powered by a lithium-ion rechargeable battery and is capable of five hours of continuous remote-controlled operation applying standard Ethernet computer network specifications.

The MARS-C comprises four modules: a platform module (movement mechanism), load lifting module (telescopic ladder), attachment module (robot arm) and end effector module (attachment tool component). The platform module features 4-wheel drive and 4-wheel steering, features that enable counter-rotation (place rotation) and lateral movement and thereby enhance the MARS-C's agility in narrow spaces. Outriggers*2 are provided to boost stability when performing work at substantial heights. The load lifting module features a 5-step telescopic extension system that can fully accommodate lifting of loads in excess of 150 kilograms (kg) at a height of 8m. The attachment module, i.e. the robot arm, has 7 joints - the same number as the human arm - ensuring outstanding articulation, in addition to compact dimensions and lightweight construction. The end effector module, i.e. the attachment tool component, is a device enabling the opening and closing of valves. It features a mechanism that enables easy tool attachment and detachment by remote control, using hydraulic pressure.

Two interlocking features are provided to prevent the robot platform from tipping over during work operation. The first continuously calculates the center of gravity as the robot shifts orientation while working, and if the gravity center becomes in danger of deviating from the outriggers' support range, an alarm is displayed to warn the operator. The second feature continuously monitors the values read by the load sensors on the outriggers, and operation is automatically halted before the robot would otherwise leave the ground. Intermodular interfaces adopt simple connection systems for the various lines: power drive, communication, hydraulic, etc. MHI intends to make open disclosure of all related information as a way of encouraging other companies to join in the ongoing project to develop robots of these kinds.

The power battery and recharging system incorporated into the robot platform are based on technologies, specially customized for the MARS-C, featured in Mitsubishi Motors Corporation's (MMC) i-MiEV electric vehicle. Use of a battery that simultaneously offers high reliability and a large capacity enables the robot, in spite of its 4-ton weight, to travel on 15° slopes and achieve a travel speed of 6 kilometers per hour (km/h) on flat surfaces. The battery enables continuous operation for 5 hours, even when the manipulator is being used at a height of 8m.

Going forward, MHI will mull development - including development in collaboration with other companies - of collapsible and pantograph type load lifting modules, and, for the attachment module, of a hydraulically driven wall crusher to perform shear failure work and deck buckets for load lifting. Regarding tools, besides the existing tool for opening/closing valves, the company looks to develop tools for applications such as welding, drilling, handling and leak detection. For the robot platform module, the company will focus on development of a crawler travel system offering strength for coping with operating surface gaps. Finally, development will also be pursued of robot technologies that enable outstanding ease of maintenance as well as increasingly sophisticated remote work operations.


■Major Specifications of MHI-Super Giraffe (MARS-C)

Dimensions (outer)

Length: 2,350mm, Width: 800mm, Height: 2,000mm

Weight

4 tons

Travel system

4-wheel drive, 4-wheel steering

Travel speed

6km/h

Load lifting mechanism

5-step telescopic ladder

Robot arm

One 7-axis arm with handling capacity of 20kg

Accessible height

Up to 8m from ground level

Attachment tool

Valve opening/closing mechanism (combination of handle rotator and opening/closing counterforce support)

Power source

Lithium-ion rechargeable battery (adopting technologies featured in MMC’s EVs)

Operating time

5 hrs

Operating method

Wireless remote control (using Ethernet)

Notes:
1 MARS: Maintenance Assist Robot System. Giraffe: Global Innovative Robot Arm For Future Evolution.
2 Outrigger: A device attached to a crane, aerial work platform and other vehicles whose center of gravity undergoes significant shifts in position. The device (or multiple devices) extends outward from the side of the vehicle and is set firmly on the ground.