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As modern unmanned ground vehicles (UGCs) are developed for military field use, the importance of highly reliable and adaptable control processes is becoming evident. A new addition to the research and development UGV community is the technology test bed (TTB), which differs from its predecessors in its unique approach to vehicle control. The TTB vehicle control has three distinct nested control processes. At the outer level is the real-time loop in which the operator sends desired commands over a radio frequency or fiber-optic link to the remote vehicle. The TTB performs the commanded function without operator observable delay making the teleoperated driving and reconnaissance activities intuitive and easy to learn. The middle control loop is the system processor command filtering and distribution loop. In this loop, the incoming operator commands are processed through ;smart driving' algorithms to prevent obvious operator error from endangering the vehicle. Once filtered, the modified commands are distributed along a dual redundant MIL-1553B bus to any of the 10 remote terminals (RTs) on the mobile base unit. Each RT is a self- contained microcontroller capable of performing closed loop control using both fuzzy logic and classical algorithms. The inner control layer is comprised of the closed loops between the respective actuators or sensors and the appropriate RTs. By separating the vehicle's functions into small control processes, each with a local dedicated controller, the vehicle offers a truly distributed control approach. The clear advantages of using the nested distributed control approach include a high level of reliability, significant reduction of unique spare parts, allowance for future expansion,a nd simplicity in the integration of new devices.
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