TECHNOLOGY FOR CHANGE

Swimming Lessons: Robotic Fish Masters New Strokes

Stan Gibson | Date: 08-25-09 | Comments

MIT researchers have developed a low-cost, durable robotic fish that could be used for anything from exploring shipwrecks to patrolling ports to help secure them against terrorist attacks.

If it swims like a fish�it�s far ahead of other robots. MIT researchers have come up with a simple, low-cost swimming device that opens up intriguing possibilities for real-world applications.

�The fish was an application of the main idea of my dissertation, which was, How can we make mobile robots that are more robust and resilient?� said Pablo Valdivia Y Alvarado, research affiliate in the department of mechanical engineering at MIT. The goal was to go beyond earlier robotic fish, such as MIT�s �Robotuna� of 1994. Although Robotuna worked, its design was complex and used a number of motors, linkages and cables. �In the real world, it would not last,� said Valdivia Y Alvarado.

MIT�s latest fish, which mimic bass and trout, are only 5 inches long and are made from a continuous piece of polymer. The design breakthrough came in the study of natural vibrations of flexible bodies. The researchers molded a fishlike body and then embedded a mechanism that creates the swimming motion through concentrated torque.

A durable low-cost robotic fish promises to be useful in a number of practical applications. It could perform exploration and surveillance in dangerous underwater locations, such as near oil rigs and shipwrecks. With a camera, it could visually check machinery for leaks. It could also carry measurement devices and sensors to check levels of toxic chemicals. In another application, it could patrol ports to help secure them against terrorist attacks, said Valdivia Y Alvarado.

Depending on their level of complexity, the fish could be made for $100 to $1,000 each, prices that could permit them to be expendable in some hazardous work.

The current prototypes have a power cord. Future versions will be battery-powered. Additional fish prototypes are under development, including a manta ray. A salamander, an amphibian, is also on the drawing board.

Future work could sonar-enable the fish and get them to work together in a school, said Valdivia Y Alvarado.