Researchers at the US Army Research Lab are testing a carbon-fiber exoskeleton arm originally developed to assist in the rehabilitation of stroke victims as a way to help stabilize firearms and allow soldiers to aim them more accurately. The Mobile Arm eXoskeleton for Firearm Aim Stabilization (MAXFAS) project has thus far only been used in static testing with external hardware, but experiments have shown that it can help improve the aim of soldiers with handguns even after they've stopped wearing it.

Dan Baechle, lead investigator on MAXFAS at ARL, described the system as being the equivalent of image stabilization—except that it actually stabilizes the entire arm of its wearer. “Imagine the benefits of using an image stabilizer for a camera when the photographer is capturing action shots," Baechle told the Defense Department's Armed With Science weblog. "MAXFAS provides that level of stability for your entire arm during the critical moments of aiming and shooting. The MAXFAS exoskeleton senses the tremors in your arm that you probably don’t even realize exist. The control algorithms for the device dramatically reduce the shake without locking your arm in place."

Aided by computers processing the sensor data from the carbon-composite arm exoskeleton, MAXFAS applies small amounts of force to counteract the shaking of a shooter's arm. As a result, the shooter is able to more easily stay on target. Baechle said that as far as he and ARL have been able to determine, an exoskeleton has never been used to improve the accuracy of firearms. "Typically, exoskeletons are devices designed for strength or endurance enhancement.”

Baechele began work on MAXFAS as his master's thesis project at the University of Delaware, modeling his work in part on the ALEX and ALEX II exoskeletons developed at the University of Delaware's Mechanical Systems Laboratory—tethered leg exoskeletons used in the rehabilitation of stroke victims. The ALEX systems help train a patient's walking gait, applying force on the leg to adjust its motion as needed to ensure that the leg travels along a predetermined path. Through training with ALEX during rehabilitation, patients' walking gait improved.

As with ALEX, tests with MAXFAST showed that it could be used to train users to aim better without using the exoskeleton. "Of course we have to perform more tests to find out how long that effect lasts, but these initial results indicate that MAXFAS could be used to train soldier marksmanship faster and more effectively," Baechele said. It's also possible that MAXFAS could be developed into an untethered, mobile version, he added, "that could be worn by combat arms soldiers on the battlefield to actively improve shooting performance.” But that will require a great deal more work.