Asynchronous control of rotation and translation for a robot vehicle

Robot arms require an "arm controller" to command joint motors to achieve a coordinated motion in an external Cartesian coordinate space. In the same sense, robot vehicles require a "vehicle controller" to command the motors to achieve a coordinated motion specified in terms of an external Cartesian coordinate space. This paper presents the design of a general purpose vehicle controller. The vehicle controller is designed as a three layer structure. The top layer is an interpreter which assures a control protocol based on asynchronous commands and independent control of orientation and forward displacement. The middle layer is a control loop which maintains an estimate of the vehicle's position and orientation, as well as their uncertainties. The control loop generates estimates and commands translation and rotation in terms of a "virtual vehicle". The bottom layer is a translator between the "virtual vehicle" and whatever physical vehicle on which the controller is implemented.