Nahant-based scientist develops robotic creatures with nervous systems that someday may be used to save lives
Joseph Ayers has some cool toys. His robotic lobster can move in any direction, like a real lobster. His sea lamprey can swim.
Someday, the robots may be used in military applications to blow up underwater mines, or to enhance the lives of patients with traumatic brain injuries.
Ayers, a professor at Northeastern University with a doctorate in biology, is working to create robots with nervous systems that will allow them to wiggle and squirm as animals do. Eventually, that technology will be used to help rehabilitate people with movement disorders.
Ayers began studying the movements of sea animals in 1970 as a student at the University of California at Santa Cruz. His doctoral thesis focused on a study he had done on the control of walking and lobsters.
"I had the only refrigerated optical lobster treadmill in the world at the time," said Ayers, who works at Northeastern's Marine Science Center in his hometown of Nahant. "We were initiating locomotion with optical flow."
An omnidirectional walking lobster that made it to the Smithsonian was completed in 1999, and a more sophisticated version was developed in 2002. Ayers also had developed a robotic sea lamprey, with all of the work funded by grants through the Defense Advanced Research Projects Agency, the central research and development arm of the US Department of Defense, and the Office of Naval Research.
Both the lobster and the lamprey are the average size of their biological counterparts.
All of the prototypes remain at the basic research stage, Ayers said, but the hope is that someday they will save lives.
Their purpose: To be used to plant the charges that will explode underwater mines in shallow water near shores in harbors and inland waterways. Trained dolphins will find the mines and mark them with sonar beacons. The robots, equipped with sonar equipment, will follow the sounds to the mines and detonate them.
"Right now, they send in an 18-year-old kid, a Navy SEAL, with a satchel charge," Ayers said.
The biomimetic robots work in a "supervised, reactive, autonomous" way, which means that instead of being run by remote control, Ayers said, "you give it a goal and it goes and achieves that goal."
The practice of using robots to explode mines has been used during the Iraq War, but underwater terrain is difficult to traverse. In the version of the robot lobster currently being developed, Ayers is creating a nervous system that will allow the robot to maneuver more effectively on the ocean floor.
"Unless you explicitly program the robot to anticipate every possible situation it can get into, it's going to get into situations where it gets stuck," Ayers said. "Now, animals never get stuck [because] animals can wiggle and squirm, and, as a result, they're able to get out of spots that a machine can't get out of. What we think the animals are doing is increasing the level of chaos in the networks that would otherwise generate locomotion, and the chaotic variations on the programs are the wiggling and squirming."
Chaos occurs when an animal goes into random patterns of movement, with no predictable system, explained Ayers, who used the examples of a cornered fox jumping off walls to escape capture or an animal getting stuck as it crawls through a small hole.
"In these very simple animals, they go chaotic in ways that, to all intents and purposes, look like random behavior, but by exploring all their possible options until they find one that works," he said.
Joel Davis, retired as program officer for the Office of Naval Research, said that Ayers's design will be particularly valuable when there is a need to navigate the difficult terrain of the ocean bottom.
"The lobster's going to be very good in rocky terrain, and in terrain where there is what we would call a [water] surge," Davis said. "The sea lamprey is good for another kind of situation - more open water, more flat bottom, where you want to survey a larger area. They are designed to survey two different kinds of environments."
In addition to detecting or detonating mines, Davis said, other uses for the robots may be found, such as port security.
The units could be manufactured inexpensively if they got into mass production, said Ayers, who noted that they also could be used to clear mines in waterways where the explosives still sit but are no longer in militarized zones.
Another future use for the research: To help rehabilitate those who have sustained traumatic brain injuries.
Ayers is working with Edward Taub, a professor at the University of Alabama at Birmingham who has pioneered constraint-induced movement therapy. CI therapy is a family of therapies that teaches the brain to "rewire" itself, retraining it by having the patient make movements such as gripping a tennis ball and moving it from one location to another, or taking a marble and placing it on a Chinese Checker board, and then improving on the movement the next time.
"We have evidence that CI rewires the brain," Taub said. The therapy has been used with stroke victims and patients with multiple sclerosis and cerebral palsy, as well as with victims of traumatic brain injuries.
The latter group would be the first to benefit from Ayers's project.
By having a patient wear a garment wired with an artificial nervous system (Ayers suggests that it will resemble the garments used by actors and athletes while shooting video games), therapists hope to "jump-start" the process of CI therapy for those who have sustained brain injuries, Ayers said.
"The idea is to augment their movements using functional electrical stimulation that would be controlled by our electronic nervous system," said Ayers, who is currently seeking a grant for the project. "They can jump-start the movement process so that constraint-induced movement therapy would apply."
The stimulation the patient would receive from the electronic nervous system would decrease as the person recovers his or her range of movement, Ayers said. "We know that we can build these electronic neural networks to control movements because we build them to control our robots."
Taub said he sought Ayers out after attending a lecture at an academic conference.
"Robotics is something that I'm very interested in, and its potential for improving rehabilitation outcomes," Taub said. The wars in Iraq, Afghanistan, and other regions have created what Taub calls a "modern epidemic" of traumatic brain injuries. When he approached Ayers, Taub said, he found him to be a quick study.
"He picked it up right away and really understood it in a fundamental way," said Taub, who noted that many in the rehabilitation field are less receptive. "[Ayers] stays loose and is willing to think of things and put them into practical effect when they make sense to him."