Mechatronics and robotics

Smashable Fingers 
Sure you can make an electronic prosthetic hand that is controlled by 
person’s nervous system, but can you make one that can survive getting 
smashed by a hammer? The Bretl Research Group, led by Timothy Bretl at 
the University of Illinois at Urbana-Champaign, decided this was a 
necessary feature of prosthetic fingers. So the group fabricated an insanely 
flexible model hand, hooked it up with sensors, and, using various finger 
torture devices, smashed, twisted and bent the fingers in every direction 
(with the video camera rolling). You might wince, but the deformed digits 
just bend right back into shape.
The key was to eliminate the weak spots common in commercial 
prosthetic hands. That would be the pin joints – the hinges around 
which rigid prosthetic fingers bend, but often break. So the Bretl group 
eliminated the fragile part, replacing it with flexible materials. For each 
finger, they 3D-printed the “bone” with a flexible polyurethane 
material, routed it with pressure sensor wires, molded a silicone skin 
around it, and then inserted three layers of pre-stressed spring steel. The 
thumb is made similarly, but equipped with a motor. After being smashed 
with a hammer, the hand can pick up that hammer – or a glass of wine or a 
pair of scissors – and use it like nothing happened.
Laser-assisted robot arm tries not to be a bull in a china shop
It’s a little awkward and slow, but this robot arm will grab and 
retrieve that hard-to-reach object you need. All you have to do is aim a 
laser beam at it. (And hope that you don’t bump into anything else along 
the way). The invention, developed by researchers at the Robotics Lab at 
University of Massachusetts Lowell and the Helping Hands Lab at 
Northeastern University, aims to aid people who use mobility scooters. 
Home robotic arms are expensive and often challenging to operate, and this 
team of engineers wanted to make something simple enough that any 
scooter rider could use it. 

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So they mounted onto a mobility scooter a robot arm, and equipped 
both the scooter and the arm with depth cameras similar to the Microsoft 
Kinect Sensor, which is used with Xbox. When the user aims a laser beam 
at the object she wants, the robot arm moves to that object, the camera 
scans it, and the team’s grasp detection algorithm determines how to 
maneuver itself in order to pick it up. The contraption got it right about
90 percent of the time, the team reported at ICRA. Unfortunately the thing 
is huge and the arm tends to collide with other stuff in the room. That 
could be resolved by adding more depth sensors, the team reported.