Friday, April 11, 2008

Exoskeletons

Pneumatic. [Link]

The Soft Pneumatic Exoskeleton (developed in the Wearable Studio at ITP, NYU) is a soft and lightweight wearable pneumatic muscle suit for the lower extremities. Pneumatic muscles are worn around the leg to assist the user in lifting loads, muscle reinforcement and walking. Unlike other exoskeletons, this application is untethered and constructed primarily of soft materials, making the device lightweight, portable, and comfortable. The system is built to sustain an idle-power state and is activated as muscle assistance is needed. Primary concerns are weight, comfort, and flexibility.

The Pneumatic Soft Exoskeleton is worn by strapping components of of the system on parts of the leg to align the pneumatic muscle to major muscle groups in the leg. Synchronized actuation of the pneumatic muscles add to the user’s own movements providing support and power. The system is powered by a ‘pony’ size scuba tank and is triggered by the user’s motions through flex and force sensors worn on the body. A force sensor under the foot activates the air muscle around the calf and a flex sensor behind the knee activates the air muscle around the quads.

Pneumatic muscles work by inflating a silicon tube within a plastic braided sleeve. The inflation of the tube shortens the overall length of the assembly as the braided sleeve increases radially.">1 Pneumatic muscles are a relatively recent development in air powered actuation, lead by the Shadow Robot Company, and FESTO Corporation. They were originally commercialized by The Bridgestone Rubber Company in the 1980’s. Air Muscle videos: http://www.youtube.com/watch?v=w77YDDTXfRc&NR=1, http://www.imagesco.com/articles/airmuscle/AirMuscleDescription03.html">2 Pneumatic muscles use simple materials that have a low cost to manufacture and are extremely lightweight. A fully assembled muscle can potentially have a 1:400 weight to strength ratio (compared to the 1:16 ratio of pneumatic cylinders and DC motors).">3 The assembly is also flexible, cushioned, and operates smoothly, making it an ideal candidate as an artificial muscle for a wearable application.

Powered exoskeletons, currently developed within research groups around the world, are focused on assisting human locomotion through a wearable machines.4 Actuated parts of the machine coincide with the body and gross muscle groups to help lift heavy loads. A suit for the upper extremities has been created by Hiroshi Kobayashi, a roboticist from the Science University of Tokyo.">5 Dr. Daniel Ferris and Dr. Riann Palmieri-Smith lead a group of researchers at the University of Michigan in creating pneumatically powered exoskeletons for the lower limbs.6

The Soft Pneumatic Exoskeleton does not use off-the-shelf air muscles, since it requires custom lengths. The result is a more affordable air muscle that can be tailored to specific lengths and strengths. Pneumatic muscles are strapped to the calf and quad muscles on each leg with a nylon reinforced leather holster. Air flow of each pneumatic muscle is controlled by a single tube from a 3-way solenoid valve which controls the air flow in and out of the pneumatic muscle from a portable air reservoir. Each solenoid is controlled by outputs from a battery powered Arduino board. Switches from the user’s inputs are fed to the Arduino board to control the actuation of the artificial muscles.

And Mechanical. [Link]
He could easily knock a nearby coder to the floor, or fling one over a desk—but even more impressive, he could do it all day. To show off his superhuman endurance, he walks over to a weight rack and yanks down a bar loaded with 200 pounds. Then he does it again. And again. He stops somewhere around 50, but he's been known to rip through 500 reps in a row. Even then, he quits out of boredom, not fatigue.

It's fantasy versus reality, and the spread is shrinking. The latter, the XOS, is the latest and arguably most advanced exoskeleton in existence, developed by one-man idea factory Steve Jacobsen and the engineers at Sarcos, a robotics company he started in 1983 that was recently purchased by the defense giant Raytheon. The flame-throwing monster? That's the star of the superhero blockbuster Iron Man, due out May 2. The film follows a prolific inventor named Tony Stark who builds a robotic suit of armor that grants him fantastical abilities. Iron Man has been thriving in comics for more than four decades, but this is Hollywood's first go at the story. And the timing couldn't be better. Not only is Iron Man—a hero born of pure engineering—the perfect idol for our gadget-obsessed era, but for the first time since the character appeared, the suit is more than just an illustrated dream.

In the past seven years, a handful of engineers have taken the military's 40-year-old fantasy of mechanically enhanced soldiers that can carry heavy loads and begun to make it real. Funded with millions from the Pentagon's Defense Advanced Research Projects Agency (Darpa), Jacobsen and others have finally begun marrying artificial muscles and control systems into suits that could soon be available to soldiers, firemen and the wheelchair-bound. There are still serious challenges—powering these wearable robots, for one—but Sarcos's XOS, the most capable full-body suit, one that moves seamlessly with its wearer, has even the comic's creators feeling like the real world is catching up to their vision. After Adi Granov, one of the main illustrators of the comic and a consultant to the film, watched a clip of the suit in action, he was startled. "I knew that's where we were heading, but I didn't realize we were this close," Granov says. Aside from the lack of flight and weapons, he adds, "that's Iron Man."

Video.

And fictional.

No comments:

Post a Comment