Abstract: A mobile base movable relative to a surface is disclosed. The base includes a main housing having at least two wheels pivotably and rotatably mounted to the housing with each wheel having a steering axis and a rotation axis. The steering and rotation axes are nonintersecting and are offset by a known caster distance. Further, included are drive means for rotating the wheels to roll along the surface, steering means for pivoting the wheels and changing their heading with respect to the surface, and controller means for reading an input vector from a host processor. The input vector is a three dimensional force torque vector.

Abstract: A drive system base or platform, such as for a mobile robot, is disclosed having multiple caster wheels, each wheel having its own first motor for independent driving and its own second motor for independent steering. Each wheel is rotably and pivotably mounted in a separate wheel module, which includes both the driving and steering motors associated with the wheel. All of the wheel modules on the base are identical and interchangeable. The two motors of each module are mounted side by side in a vertical arrangement for compactness. Each wheel module includes a suspension for allowing each wheel to move vertically and independently relative to the base. The hub and tread of each wheel are each cast concentrically around a bevel drive gear in an offset manner to provide a wheel and bevel gear that turn more smoothly and precisely.

Abstract: An apparatus for generating analog signals, comprising at least one monolithic direct digital synthesis (MDDS) circuit producing an analog MDDS output signal and having at least one digital MDDS input for specifying a desired signal characteristic of the MDDS output signal; one clock generating one clock signal coupled to all the MDDS circuits; and a microprocessor executing a computer program that communicates the desired signal characteristics to the MDDS inputs. The MDDS devices operate at a high clock frequency but generate signals with a low frequency, e.g., 60 Hz. The system monitors its outputs and can maintain its output levels under different conditions. Since all of the signals have a common phase reference the relative phase between the different signals can be programmed.