In the world of robotics, iden­ti­fying actu­a­tors that are strong and com­pact is prob­ably one of the most impor­tant open tech­no­log­ical prob­lems yet to be resolved. More often than not, the mechan­ical ele­ments that trans­late data into doing are big, rough, and gen­er­ally unfriendly for use in everyday robotics, said Dinos Mavroidis, Dis­tin­guished Pro­fessor of Mechan­ical and Indus­trial Engi­neering at North­eastern University.

In the mid-​​2000s, Mavroidis’ lab set out to develop a new kind of actuator—small enough to sit inside the joints of pros­thetic limbs, but pow­erful enough for everyday tasks such as lifting and walking.

Backed by two new grants—one from the National Sci­ence Foun­da­tion, the other from the National Aero­nau­tics and Space Administration—Mavroidis’ team will work to tailor the tech­nology for use in advanced space appli­ca­tions as well as everyday house­hold robots.

The gear bearing drive, or GBD, as the team’s unique actu­ator is called, con­sists of a motor embedded directly inside the gear trans­mis­sion, allowing for cheaper, lighter, and stronger func­tioning. The GBD is a com­pact mech­a­nism with two key abil­i­ties. It oper­ates as an actu­ator pro­viding torque and as a joint pro­viding sup­port. Back in 2006, Mavroidis and then grad­uate stu­dent Brian Wein­berg devel­oped the idea in col­lab­o­ra­tion with John Vranish, a NASA God­dard Space Flight Center engineer.

Elias Bras­sitos, a doc­toral can­di­date in Mavroidis’ lab, will use funding from a Space Tech­nology Research Fel­low­ship to develop the GBD for use on the Mars Rover. “For space appli­ca­tions, every­thing needs to be lighter and stronger,” said Bras­sitos, who noted that the device would replace the entire joint assembly for the rover’s manip­u­lator, the arm that extends out­side the vehicle to col­lect rock sam­ples and other things

Mobile Robotics, par­tic­u­larly the use of rovers as part of a wider NASA explo­ration strategy, puts pres­sures on actu­a­tion tech­nology,” said Brett Kennedy, super­visor of the Robotic Vehi­cles and Manip­u­la­tors Group at the Jet Propul­sion Lab­o­ra­tory in Pasadena, Calif. “We are always looking for ways to pack more torque, more power, and more func­tions into smaller pack­ages,” added Kennedy, who has high hopes that the GBD will help them do just that.

First, Bras­sitos must design var­ious GBD archi­tec­tures, each of which might be good for dif­ferent appli­ca­tions. He’ll design and build a pro­to­type at North­eastern, and then assemble and test the device at the JPL.

While Bras­sitos works to develop the GBD for space, another grad­uate stu­dent will work to “com­mer­cialize it for earth.”

In col­lab­o­ra­tion with the startup com­pany Foo­d­inie, which aims to make robots for the modern house­hold kitchen, doc­toral can­di­date Andy Kong and Mavroidis are devel­oping an off-​​the-​​shelf ver­sion of the gear bearing drive that inven­tors can use for a variety of appli­ca­tions. In some cases, the team will develop it for spe­cial­ized needs as in the case of the Mars rover.

There is a pos­si­bility for the GBD to be a source for inno­va­tion in the area of com­pact actu­a­tors for robotic sys­tems,” Mavroidis said.