System Prototypes

Figure 3. The RC prototype traverses an internal corner (top), and climbs an exterior corner.
Two prototypes were developed. The first, a two-segment robot with RC components, was developed to quickly test different variations of subsystem components such as the drive module, magnetic wheels, and linkage. The second, a three-segment system with integrated processors, will be used to develop coordinated control software for the system (see Figure 2).

The RC prototype was tested with a variety of different linkage concepts. The yaw-bow linkage only provided a single DoF in the yaw axis, but proved the most effective of those tested with the RC controller. The system successfully climbed at 0.5 foot/second and negotiated internal corners, external corners, and obstacles as big as 3". It could also turn on vertical, horizontal, and inverted horizontal ferrous surfaces (see Figure 3). The linkage did not provide a roll DoF, resulting in the loss of wheel contact if an obstacle or angular transition was not traversed orthogonally to vehicle motion. Often, when wheel contact was lost, the robot would fall from the surface being climbed. It is expected that the addition of a roll DoF would improve the system’s mobility.

Conclusion

The prototype systems demonstrated that a multi-segmented magnetic robot with relative DoFs between modules can effectively climb and negotiate surfaces with discontinuities, obstacles, internal corners, and external corners. Additional development of the mechanical, electrical, and software systems is required before the system is ready for testing in operational scenarios. The technology is promising for use in maritime interdiction operations and vessel hull and tank inspections, with the potential to increase safety, effectiveness, and efficiency of personnel involved in maritime operations.

This article was written by Aaron Burmeister, Narek Pezeshkian, Kurt Talke, Abraham Hart, and Gary GilBreath of SSC Pacific, San Diego, CA. For more information, visit www.public.navy.mil/spawar/pacific.