Team aims to more accurately predict physical behavior of newly designed robots

Researchers from Texas A&M University, Rice University and Halmstad University in Sweden are collaborating to develop a new generation of design software that can accurately predict the physical behavior of robots prior to prototyping.

"One of our goals is to find a way to do virtual testing so that key flaws can be found on a computer before a prototype is ever built," said Walid Taha, adjunct professor of computer science at Rice University and professor of computer science at Halmstad University.

Taha is principal investigator at Rice and Halmstad University on a new collaborative research grant from the National Science Foundation (NSF).  The lead investigator at Texas A&M is Dr. Aaron Ames, an assistant professor in the Department of Mechanical Engineering with a joint appointment in the Department of Electrical and Computer Engineering.

Taha said that robots are a study in contrasts. They can perform superhuman feats and get tripped up by toddler-level tasks. They're digitally programmable, but intricacies of their physical behavior go far beyond the reach of computer simulations.

"Part of the problem is that robots have a foot in both the digital and physical worlds," said robotics researcher Marcia O'Malley, professor of mechanical engineering and materials science at Rice and co-principal investigator on the new project. "Bridging these worlds is difficult. The physical world is a messy place with both smooth curves and discontinuities that are difficult for computers to deal with."

The upshot is that designing robots today goes something like this: Build computational models and test in simulation. Build prototype at great expense. Test prototype and find unanticipated flaw. Revisit simulation. Redesign prototype. Repeat.

Taha, Ames and their collaborators at Rice said they hope to change that with new funding from the NSF's Cyber-Physical Systems program.

Modeling and simulation of robotics is not a new idea, but the researchers are taking a new approach. For one thing, they are keen to develop a holistic system that robotics designers can use from start to finish. Currently, designers might use four or more different pieces of software at various points in the design and testing of a new robot. Lack of compatibility from one piece of software to the next is one problem, but an even larger problem can arise when entire concepts are missing or treated wholly different.

To address this, the team includes Rice programming language expert Corky Cartwright, professor of computer science. Taha, principal investigator on the project, and Cartwright began developing a new programming language called Acumen under an earlier NSF grant. They'll continue to develop and expand the language under the new research program.

This new programming language will be applied in the context of the project's two hands-on robotics laboratories — O'Malley's Mechatronics and Haptics Interface (MAHI) lab at Rice and Ames' A&M Bipedal Experimental Robotics (AMBER) lab at Texas A&M — to test the language and make sure it is up to the task of day-to-day robotic design. O’Malley will create novel upper-body prosthetic and rehabilitation devices through this framework. Ames will focus on lower body robotic devices, developing the next generation of two-legged walking robots and lower-limb robotic assistive devices through this new software infrastructure.

Ames said, "One area that stands to significantly benefit from these innovations is the design of next-generation prosthetics. The MAHI lab at Rice is already doing work on upper-body prosthetics, and the AMBER lab is working on prosthetics for the lower body. With improved modeling and simulation tools we hope to dramatically accelerate innovation in this area."

Ames joined the Texas A&M Engineering faculty in 2008 after a postodoctoral fellowship at Caltech. His research interests center around theoretic methods in nonlinear dynamical, control and hybrid systems, with a special emphasis on human-inspired applications of geometric and topological techniques to robotic systems — and specifically bipedal robotic walkers. His AMBER lab is devoted to both theoretical and experimental research in bipedal robotics, human locomotion, and prosthetic design.

Ames received the 2010 NSF CAREER Award for his project, "Closing the Loop on Walking: From Hybrid Systems, to Bipedal Robots to Prosthetic Devices and Back." He earned a B.S. in mechanical engineering and a B.A. in mathematics from the University of St. Thomas in 2001. He also received an M.A. in mathematics and a Ph.D. in electrical engineering and computer sciences from the University of California, Berkeley in 2006.

Provided by Texas A&M University