Crab Crawl Maneuver for Independently Steerable Wheeled Platforms

An industrial-class excavator was developed for use on the Moon and perhaps on Mars. The model mobility platform uses Ackerman Steering with active drives on all six wheels, and steering on the corners. A faulty sequence of wheel steering and driving commands resulted in undocumented behaviors in a simulation and rendering program that appear to have actual applicability to surface operations. Quite by accident, it was discovered that by applying power and steering to the wheels in a complex pattern, the excavator could move laterally, hard to starboard. The intended command was “reverse,” and the execution was a seemingly random turning and driving of all of the simulated six wheels. The faulty behavior was employed to remove the robotic platform when it was stuck on rocks, and enabled the platform to “scoot” side-ways, successfully disentangling from the rocks. The method drove the wheels in the direction of the intended motion, while steering them in a sweeping motion, and the apparent motion resembles swimming.