Robots play catch

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From: http://www.newscientist.com/article.ns?id=dn7790

Robot catcher grabs high speed projectiles

* 16:12 04 August 2005

* NewScientist.com news service

* Will Knight

If robots are to inherit the Earth, then they should at least be able to catch. So say the researchers behind a bot that can match the most skilled human baseball player faced with a hurtling ball.

The robotic catcher, developed by scientists at the University of Tokyo, Japan, can comfortably grab a ball careering through the air at 300 kilometres per hour, or 83 metres per second, its creators say. And, of course, the robot never gets tired of doing so.

Akio Namiki and colleagues built the robot to test technologies that could some day make robots useful in situations where they may have to react at high speed.

"The need for a robotic hand that works in the real world is growing," Namiki told New Scientist. "Such a system should be able to adapt to changes in its environment and we think that the concept of high-speed movement with real time visual feedback will become an important issue in robotic research."

Lightning reflexes

The robot does not even need a catching mitt. It resembles a single metallic claw, with just three fingers instead of the human complement of five. An array of 32 by 48 individual photo detectors in its “palm”, tracks a ball's trajectory at high speed. And a series of specialised image processing circuits recognise this movement almost instantly.

An approaching ball triggers the robot's three fingers into action. Actuators embedded in each joint use a burst of high current to move through 180 degrees in less than one tenth of a second. This enables the machine to snatch the ball in the split second it takes to arrive.

The robot can be seen catching balls pitched from various different directions by a human controller, in a short video (9.3MB Windows Media Video) demonstration posted to the researcher's web site.

Industrial robots

"It's an extremely difficult task as the ball is moving so fast," says Ulrich Nehmzow, an expert in mobile robotics at the University of Essex, UK.

He adds that the speed and accuracy of the robot goes well beyond that of ordinary industrial robots. "If you are able to locate a moving object so reliably that you can actually catch it, then picking an object up should be child's play," he says.

However, Nehmzow notes that it is difficult conceive of ways that such a robot could be used today. "It's an engineering feat really," he says.

The system is yet not sturdy enough to catch a real baseball and was only tested with soft balls. But, in other tests, it proved adept at grasping objects of various shapes, including cylinders.