Researchers at the University of Arizona's department of electrical and computer engineering have developed a pair of robotic legs that walk with a biomechanically accurate gait. Modeled after human walking mechanisms, the legs and an attached pelvis are part of an effort to create human-like service robots.
The robot's movements emulate the neuromuscular architecture of human walking, which results from interactions among the musculoskeletal system, the nervous system, and the environment. The movements are made possible by emulating those three elements with mechanics, a complex central pattern generator (CPG) that constitutes the neural network, and feedback from sensors.
The researchers, Anthony Lewis and Theresa Klein, say that combining all three elements makes up a complete physical model of the human walking system, making it much more accurate. In an article published in the Journal of Neural Engineering, they claim: "We believe that this is the first robot which fully models walking in a biologically accurate manner." Another walking robot, Boston Dynamics' Petman, has learned how to walk up stairs.
The robot uses artificial leg muscles attached to Kevlar straps that move up and down as actuators, mimicing the natural agonist/antagonist muscle action of human legs. Each muscle consists of a servo motor attached to a bracket. The motor rotates to pull on the strap to mimic muscle contraction. The Golgi tendon organs of human legs are modeled by load sensors in the straps, while load sensors in the feet help a computer adjust the half-size legs' motion according to the surface they are walking on. The CPG is made up of a half-center oscillator plus phase-modulated reflexes that are simulated with a spiking neural network. The robot incorporates "positive force feedback from load sensors as well as other afferent signals to entrain the CPG and drive the step cycle." The robot's neural architecture is enough to produce a propulsive, stabilized walking pattern.
The purposes of this research are both using biology as an inspiration for robotics, and also a method for investigating biological systems. This type of robotics research is sometimes called "soft" robotics. It aims at developing humanoid service robots for use with people such as the elderly, instead of robots that are used in an industrial context. For example, the legs developed by Lewis and Klein are constructed so that they give somewhat when pushed, like organic legs, instead of being rigid and inflexible like an industrial robot.
Although the research is basic and aimed at robotics, it could also be applied to helping people with spinal cord injuries learn to walk again by assisting medical professionals in understanding the biomechanics of how people walk.
Thanks for that definition, ScotCan. If that's the accepted definition of "fully autonomous," we're definitely not there yet in robotics. I agree, HMI plus partially autonomous robots makes a lot more sense.
It depends on the interpretation of autonomous. My understanding is that fully autonomous means a robot's capacity to learn from its environment and carry out its actions accordingly.The human factor processes much more information than any computer because of the wide ranging human response to its environment...most times to the benefit of circumstances, but sometimes in error. That's why HMI makes more sense than attempting to build fully autonomous robots. Use HMI to confirm the robot's feedback and implement corrective action as a Human/Machine team, rather than to be fully automated. As for robots which send back info from far away (e.g. the drones) there's a time lapse in there which could affect decisions adversely....the physical distance between the controller and the robot needs to be reduced since there are at least 8 time dependent signal "journeys" between sending info, receiving it, deciding a course of action, transmitting it back and when the robot gets the instruction for it to trigger the action...by that time, however small, the circumstances could have changed, even in the case of a drone which has locked on to a specific target.
ScotCan, can you define what you mean by "fully autonomous"? Autonomous robots already exist. Some of them have the option of being controlled remotely, and many can send back data to a remote human, using various forms of communication.
That robot running at 28MPH was very impressive. It was more like a gallop than a run, though. Not quite horse style yet, and it looks like "horse style" would have a better ability to balance. A robot as stable as a horse would certainly have a whole lot of applications. It might even be useful in getting around city traffic jamups. And the military uses would be totally demoralizing to the enemy. Just imagine, if the robots were dressed as soldiers, running in a charge, firing automatic weapons with both "hands". That would make almost everybody drop and run.
The Navy robot probably has a Human/Machine Interface since once the robot has entered the fire zone the decision process would be handled by the human supervisor. Since the robot is working locally it makes sense to have an umbilical cord carrying all the relevant data back to a central control...a fully autonomous robot is still down the pike a bit.
I think it's an understandable bias, Ann. If we're trying to get a machine to replicate human movement -- as with the fire fighting robot -- it makes sense that we work with the solutions we already know and understand, our own movements.
Yes, the crawlers may make more sense when it comes to movement. I still keep thinking there is a bias toward robots with human attributes -- like legs. Replicating human movement may not make the most sense.
Rob, that's a really good point. We featured crawling robots in the Bugs and Worms robot slideshow:
and some of them, as well as other, snakelike robots, do workarounds and learn. I think the problem with the legs versions is that they're more likely to tip over because of a much higher center of gravity.
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