A versatile mobile telerobot, denoted the magnetically attached multifunction maintenance rover (MAGMER), has been proposed for use in the inspection and maintenance of the surfaces of ships, tanks containing petrochemicals, and other large ferromagnetic structures. As its name suggests, this robot would utilize magnetic attraction to adhere to a structure. As it moved along the surface of the structure, the MAGMER would perform tasks that could include close-up visual inspection by use of video cameras, various sensors, and/or removal of paint by water-jet blasting, laser heating, or induction heating.

Figure 1. The MAGMER, Deployed From a Truck, would move along a ship hull surface. It would adhere to the hull by magnetic attraction.
The water-jet nozzles would be mounted coaxially within compressed-air-powered venturi nozzles that would collect the paint debris dislodged by the jets. The MAGMER would be deployed, powered, and controlled from a truck, to which it would be connected by hoses for water, compressed air, and collection of debris and by cables for electric power and communication (see Figure 1). The operation of the MAGMER on a typical large structure would necessitate the use of long cables and hoses, which can be heavy. To reduce the load of the hoses and cables on the MAGMER and thereby ensure its ability to adhere to vertical and overhanging surfaces, the hoses and cables would be paid out through telescopic booms that would be parts of a MAGMER support system.

The MAGMER would move by use of four motorized, steerable wheels, each of which would be mounted in an assembly that would include permanent magnets and four pole pieces (see Figure 2). The wheels would protrude from between the pole pieces by only about 3 mm, so that the gap between the pole pieces and the ferromagnetic surface would be just large enough to permit motion along the surface but not so large as to reduce the magnetic attraction excessively. In addition to the wheel assemblies, the MAGMER would include magnetic adherence enhancement fixtures, which would comprise arrays of permanent magnets and pole pieces that could be adjusted to maximize or minimize the overall attractive magnetic force.

Figure 2. One of the Four Wheel Assemblies of the MAGMER is depicted here with the surface adhering ends of the magnetic pole pieces facing upward.
Even with a paint thickness of 2 mm, a preliminary design provides a safety factor of 5 in the magnetic force in the upside-down, water-jets-operating condition, in which the total load (including the weight of the MAGMER and cables and the water-jet force) would be about 260 lb (the weight of 118 kg). Optionally, the MAGMER could carry magnetic shielding and/or could be equipped with a demagnetizing module to remove residual magnetism from the structure.

The MAGMER would carry four charge-coupled-device cameras for visual inspection, monitoring of operation, navigation, and avoidance of collisions with obstacles. The control system of the MAGMER would include navigation and collision-avoidance subsystems that would utilize surface features as landmarks, in addition to direct images of obstacles.

This work was done by Yoseph Bar-Cohen and Benjamin Joffe of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Machinery/Automation category. In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to: Innovative Technology Assets Management

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E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. Refer to NPO-20229, volume and number of this NASA Tech Briefs issue, and the page number.

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Magnetically Attached Multifunction Maintenance Rover

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NASA Tech Briefs Magazine

This article first appeared in the July, 2005 issue of NASA Tech Briefs Magazine (Vol. 29 No. 7).

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Overview

The document presents an overview of the Magnetically Attached Multifunction Maintenance Rover (MAGMER), a robotic device developed by NASA's Jet Propulsion Laboratory (JPL) aimed at automating maintenance tasks on large ferromagnetic structures, such as ships. MAGMER utilizes strong magnetic wheels that allow it to adhere to surfaces while performing various functions, including paint removal, surface scanning, cleaning, painting, and inspection.

Weighing only 125 lbs, MAGMER is designed to carry additional equipment, bringing the total assembly weight to approximately 260 lbs. It is equipped with a CCD camera for visual inspection, a paint removal module for surface preparation, and a water nozzle unit for cleaning tasks. The device has been engineered to operate with a safety factor of five times the associated load, ensuring reliability during its operations.

The need for such a device arises from the routine maintenance requirements of industries that utilize large structures made of ferromagnetic materials. These tasks often include paint removal, cleaning, and inspections, which can be labor-intensive and pose safety risks to maintenance personnel. By automating these processes, MAGMER aims to reduce operational costs, enhance the reliability of structures, and improve the safety of workers.

The document also highlights the interest MAGMER has received from the Navy and Pratt and Whitney, indicating its potential applications in military and aerospace sectors. The rover's multifunctionality positions it as a valuable tool for various industries that require regular maintenance of large metal structures.

For further information, the document provides contact details for the Innovative Technology Assets Management at JPL, as well as resources for additional research and technology related to MAGMER. It emphasizes that the information is part of NASA's Commercial Technology Program, which aims to disseminate aerospace-related developments with broader technological, scientific, or commercial applications.

In summary, MAGMER represents a significant advancement in maintenance technology, combining robotics and magnetic adhesion to streamline essential tasks in challenging environments, thereby enhancing efficiency and safety in industrial operations.