The Micro Autonomous Systems and Technology (MAST) Collaborative Technology Alliance (CTA) has been initiated to spur basic research in small autonomous robots, particularly in four main areas: Microsystem Mechanics, Autonomous Processing, Micro electronics, and Integration. In order to focus its efforts, the Army proposed multiple scenario missions of increasing difficulty to work towards: small unit building search (flat, straight walls, no wind, etc.), a small unit cave search (potential for wind gusts, no regular surfaces to use as reference points), and perimeter defense (longer required mission time, and range and potentially harsh environments). The size ranges considered were defined as “palm-size” and below, where no lower limit was specified.

MAST Power Survey early results. Voltage and power values areplotted, showing scattered power conversion specifications. Theseresults pose a challenging design problem, where traditionally subgramspecifications were not a requirement. However, completelyautonomous platforms with minimal intelligence are feasible.
The development of micro autonomous systems faces numerous technical hurdles. Beyond fundamental questions regarding locomotion at small scales, and cooperative group behaviors, there are ever-increasing needs for efficiency and power as each additional function on the system will require a finite amount of energy to execute its task. The needs for various locomotion modalities, as well as system sizes, are compared with existing or emerging power sources to determine feasibility.

The basic scenario is assumed to be a small building unit search, particularly emblematic of Operation Iraqi Freedom. By sending in a robotic platform, fundamental information about the current state of the building can be ascertained before soldiers are placed in harm’s way. The soldiers’ concept of how best to use such systems would likely include separate and distinct periods of locomotion and surveillance/ data sensing. For example, the robot would initially fly/crawl to a corner of a room, then stop and sense the surrounding environment. Upon sensing an “interesting” event, or after being given a command, the robot would stop sensing and locomote to a new position for a different view of the situation. Therefore, the hypothetical mission posed here is assumed to last about 21 minutes, divided among three perch locations of five minutes each, with about two minutes of ambulation/flying between perch locations. This leads to a minimum MAST system requirement of six minutes of crawling/flying, with an additional 15 minutes of sensing duties. Soldiers did indicate a desire for mission durations up to and exceeding 24 hours, the majority of which would be in the sensing/perched mode where the power draw is widely variable depending on the sensors being used.

While this 24-hour goal is not addressed in this report, techniques such as low sampling rates, reduced communications, and sleep modes should enable longer missions with little impact on the overall energy requirement.

This work was done by Brian Morgan and Sarah Bedair of the Army Research Laboratory. For more information, download the Technical Support Package (free white paper) at www.defensetechbriefs.com/tsp under the Physical Sciences category. ARL-0085


This Brief includes a Technical Support Package (TSP).
Power for Micro Autonomous Systems

(reference ARL-0085) is currently available for download from the TSP library.

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This article first appeared in the February, 2010 issue of Defense Tech Briefs Magazine.

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