Computing Platform Enhances Mobility of Micro-Robot

Draper Laboratory has designed and fabricated a micro-unmanned ground vehicle (UGV) - the High-Mobility Tactical Micro-robot (HMTM) - funded by the Defense Advanced Research Projects Agency's (DARPA) Microsystems Technology Office (MTO) under contract number N00421-01-C- 0297. It leverages recent advances in consumer electronics along with an innovative vehicle platform design to achieve a system that provides exceptional mobility, ruggedness, communications, and user interface in an easily man-portable form factor.

Setup
The HMTM robot contains a pair of cameras that feed data to an image compression board. Located at the top of the control stack on the robot, an embedded wireless platform (the Fingertip3 platform) based on the XScale processor receives the image data over a highspeed serial link, and subsequently transmits the data off of the robot via an 802.11 wireless link. The image data can then be received, decompressed, and viewed on a handheld device, such as an HP iPAQ.

Figure 2. The Fiber-Optic Gyros have a patented, all-fiber design incorporating digital signal processing.

Additionally, software on the handheld device allows the user to remotely control the robot's actions. These commands go back to the robot's computing platform via the wireless link, which then interfaces with a motor control board to operate a series of motors that maneuver the robot. All of the platform's software is implemented in Microsoft Windows CE.

Development of the serial connection between the image board and the Fingertip3 platform was a crucial piece of the development work. The link had to be very high speed to minimize control latencies. The software driver was optimized for the platforms synchronous serial interface, enabling the image board to communicate with it at the maximum rate of 1.8 Mb/s. This reduced the round-trip delay from image acquisition and wireless transfer to control activation on the handheld and motor operation on the robot.

Results
The HMTM robot is less than 20 inches long and weighs only 5 pounds. It is very rugged and highly capable of performing sophisticated actions. It has high mobility, low power consumption, and can be remotely controlled via an RF link.

The robot is designed to operate for a period of time between 30 minutes and 2 hours (depending on operations) with a 250 g NiMH battery pack, and roughly double that with Lithium Polymer cells. Initial prototypes have been used as demonstrators and for future technology exploration.

Future implementations may include long-range, cellularbased wireless control as well as sophisticated guidance, navigation, and control algorithms coupled with a variety of on-board sensors. This will allow the robot to make its own decisions.

More Information
To learn more about the HMTM robot and Draper Laboratory (Cambridge, MA), visit http://info.ims.ca/5215-330. For more information on InHand Electronics' (Rockville, MD) Fingertip3 platform, contact Keith Lowe at klowe@inhandelectronics.com or (240) 558- 2014, and visit http://info.ims.ca/5215-331.