Atlas is rockstar cross-stepper over tricky terrain

Atlas is rockstar cross-stepper over tricky terrain

Robot enthusiasts were sending up cheers this month to the team advancing Atlas into an even more human-like walker through obstacles including a bunch of cinder blocks and a balance beam. They have turned Atlas into the very credible hulk, who wins the spotlight with its display of walking, which was recorded May 1.

The video is "IHMC Atlas Autonomous Path Planning Across Narrow Terrain." Don't miss the key word "narrow." This is why the walk is being eyed as a big deal.

Narrow terrain is difficult due to the need to do tricky cross-over steps, tricky, in that there is limited range of motion in the hip joint, said the video notes. There was "a small polygon of support when one foot is directly in front of the other."

Unsurprisingly, viewer comments were in the superlatives, calling the walking excellent and amazing. One appreciative video watcher expanded, saying "This atlas design has got many things right...the design of the hips, elimination of the huge gap between the legs, its ability to now 'cat walk'. Very good indeed."

Jerry Pratt, a senior research scientist at IHMC Robotics, was quoted by Peter Holley in The Washington Post.

"If you think about everywhere a human go can go it's really incredible. We can climb mountains or go into caves or hike through snow or climb stairs." And why not: (1) the is only about three to four inches wide; (2) relatively small, narrow feet allow us to move around tight obstacles, step over barriers, all while supporting a higher center of mass that boosts us far off the ground.

The team had those moves around tight obstacles in mind for Atlas, the built by Boston Dynamics. The control, perception and planning algorithms were by IHMC Robotics. IHMC stands for Institute for Human and Machine Cognition, in Pensacola, Florida.

(What's their claim to fame: research "pushing the envelope of what is possible in the domain of robotics." It is an interdisciplinary group with expertise in areas such as engineering, computer science, mathematics, physics and interface design.)

The robot senses terrain with LIDAR and builds a map of planar regions, said the video notes. It walks across objects including suspended wooden planks and wobbly cinder blocks.

I Programmer remarked that "the robot is making all the decisions about where and how to place its feet."

The path-planning algorithm plans footsteps across the planar regions to a goal location, specified by an operator.

The robot is about 50 percent successful over this type of terrain. What's next? The team has thoughts on how to raise the success rate. As for this Atlas in real-world settings, Kristin Houser in Futurism said the recent showing brought it a step closer to one day filling in for humans on dangerous missions. She added, "the goal is for the robot to serve as an avatar for humans in dangerous emergency scenarios or even as they explore Mars."

Pratt had some interest,too, in imagining this Atlas as space explorer:

"Perhaps the most intriguing setting for using bipedal humanoid robots is extraterrestrial.

"When humans colonize other planets, Pratt said, one scenario involves sending remotely operated robots ahead to develop a habitat suitable for human beings.

"Being able to send robots that look and move like us, Pratt said, would give scientists a major advantage."


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May 11, 2019
Reminds me of when the young Kwai Chang Caine walked across the rice paper.

"When you can take the pebble from my hand, it will be time for you to leave.
You must walk the rice paper without leaving any marks. This will signify that you can walk without making any sounds."

-Only a matter of time.

Note there doesnt appear to be any tether?

May 12, 2019
It needs a little more speed. Right now it's doing the right thing by keeping static balance (center of gravity always over the footprint), but that's missing the other half of the equation which is dynamic balance.

When people walk, we swing our feet like free pendulums. This isn't easy to accomplish with motors because you can't free up the drive mechanism. When you stop applying power to the motor, the joint just locks up because the mechanism cannot be easily back-driven. The robot then has to emulate a free swing, but the motors aren't fast enough for that.

One solution is to use direct drive motors at the joint, which can swing freely when not powered, but then the power consumption actualy goes up tremendously because electric motors are rubbish at maintaining torque at low speeds. They can do it, but the efficiency is really poor.

May 12, 2019
Another solution would be to use a clutch mechanism, but that's another can of worms because it wears out by friction and causes jerky torque when you engage or disengage the clutch.

Biological muscles have the distinct advantage of being highly dynamic. They can almost instantly turn from rigid to flexible to completely limp, and then back to rigid. That's the holy grail for robotic actuators, and existing actuators do one or two right but rarely all three in a motor that is otherwise strong and light enough for the task.

There are ways to drive the motor actively to emulate the behavior, but the motors aren't yet fast enough for it. There's momentum in all the spinning parts of the mechanism, so you have to apply a lot of power to make a motor stop and change direction fast enough. With the mechanical backlash in the system, you end up with jerky motions again.

May 12, 2019
When people walk
What makes you think that the way people walk is the best way of walking? How do insects walk? How do birds walk?

"fire ants (Solenopsis spp.) travel at a rate of nine body lengths per second. Scaled up to human size, this is roughly equal to running 30 miles per hour... Roadrunners can run at speeds of up to 20 miles per hour (32 km/h)"

May 14, 2019
Why do I keep hearing music in my head from the Terminator movies when I watch these ever-improving robot videos? Probably just paranoia and no more realistic than flying robots (drones) killing people, right?

May 15, 2019
Another article on this IIRC noted that next up was a better - more human like - hip construction.

electric motors are rubbish at maintaining torque at low speeds. They can do it, but the efficiency is really poor.


Dunno about efficiency, but electric motors can have superior torque, that is the main reason why e.g Tesla outperforms ICE driven cars. I guess that it i another balance act, such motors are not suitable for other reasons.

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