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CAE

Students Take Control in Military Robotics Research

29 Jul, 2007 By: Michelle Nicolson

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Engineers-to-be at Dartmouth College design and manufacture robots that aim to improve military and emergency first response missions.

Engineering students at Dartmouth College are in the midst of a research project involving robotic design that could have key implications for military, emergency response, and homeland security applications. A team of undergraduate and graduate students at Thayer School of Engineering is investigating the concept of cooperative control, which would allow one person to control multiple, high-speed, all-terrain robots instead of requiring one solider per robot -- the current military procedure. Students have designed and manufactured the robots from the ground up, at a fraction of the cost incurred by the military. The finished products will enter the research phase next year.

Partially funded by the National Institute of Standards and Technology (NIST), the Army Research Office, and the Institute for Security Technology Studies (ISTS) at Dartmouth College, the research has the potential to reduce the costs associated with using robots for emergency first response missions that are dangerous or difficult for humans, thereby enabling resource-constrained communities to afford robotics technology for their own public safety initiatives.

When the project began in 2004, researchers were unable to locate commercially available robots for use in the study, so they opted to develop their own. This decision was made easier by the fact that the college has impressive resources available, explained Laura R. Ray, associate professor of engineering science at Dartmouth. Thayer School of Engineering has held academic licenses for PTC Pro/ENGINEER and Pro/ENGINEER Mechanica since the mid-1990s. It also houses a fully equipped machine shop, including traditional mills and lathes as well as three computerized numerical control (CNC) machines, vacuum-forming capabilities, two thermoformers, and three Stratasys fused-model deposition (FDM) rapid prototype machines. The school also offers an undergraduate course in computer-aided machine design and a graduate-level course in CAD/CAM.

"In the machine design course, students must design and build a remote-controlled robot from a kit of parts to accomplish an assigned task," Ray said. "The design is different each year. Students learn Pro/ENGINEER in this course and are expected to develop a complete assembly model and drawings by week six of the course."

The graduate-level CAD/CAM course focuses on manufacturing and structural analysis. On the manufacturing side, students are introduced to mold design for injection molding, NC machining, rapid prototyping, thermoforming, and vacuum casting. Again, the course is centered on a term project in which students design and fabricate something from the ground up.

"In past years, students have developed radio-controlled model sailboats and speedboats and sailed on a local pond at the end of the term. This year, the project was making bio-inspired robots," Ray said. "Again, students must develop a full assembly model of their design by week four, followed by mold designs that are manufactured in the school's development shop. Students save their 3D models from Pro/ENGINEER as STL files that are used directly for rapid prototyping, and they import their 3D models to software for producing NC code for machining."

Using this experience and the facilities available in the machine shop, the Dartmouth College students designed the chassis for the robots in less than 12 months. The students used Pro/ENGINEER for the design and Pro/ENGINEER Mechanica to perform structural analysis to ensure maneuverability on various terrains before creating the prototype. Furthermore, the students were able to use the 3D models to determine the optimum control and terrain algorithms for the robot, saving the time and costs of iterative prototyping, Ray explained.

Manufacturing the chassis begins by using Stratasys FDM rapid prototyping machine to bring the students' STL file of the 3D model to life. After some finish work, this prototype is used to make a silicon mold. The mold is used to pour multiple chassis using a polyurethane plastic compound in a variety of colors. The students finish each plastic chassis by sanding down any residual plastic, then populating it with motors, drive components, sensors, electronics, and a microcontroller.

"Robotics development is highly complex, involving mechanical, electrical, and software components. As a result, it is typically a very long and costly process," Ray explained. "The 3D solid modeling capabilities of Pro/ENGINEER allowed us to determine the final outcome before investing time and money in the prototype. We could be fully confident that all the parts were going to fit, minimizing the impact of rework."

Fabrication of the robots began in earnest last summer and is now complete. James Joslin, M.S. candidate, performed the majority of the mechanical design work, and undergraduate and graduate students worked on the electrical system design.

The remaining work, projected for 2008-2009, involves using the robots for the research tasks for which they were designed: studying autonomous navigation, cooperative control, mobility, and terrain diagnostics. The all-terrain robots also will be used as scout vehicles to characterize terrain and reduce the potential for robot immobilization.

The results from this study have the potential to affect military operations as well as SWAT teams and homeland security initiatives. Development has emphasized cost-effectiveness, so one of the main advantages of the research will be the availability of robotics to smaller organizations that have limited budgets.

"As we move into using the robots for research and experiments in cooperative control, it is clear that we have produced a one-of-a-kind robotic testbed," Ray concluded. "Our robots are capable of speeds and accelerations that are comparable to military robots costing over $40,000 each, yet we have produced seven of these robots for a total cost of about $35,000."