Robotica #2

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MIT ‘cheetah’ robot rivals running animals in efficiency

Robot’s custom-designed electric motors are powerful and efficient.

A 70-pound “cheetah” robot designed by MIT researchers may soon outpace its animal counterparts in running efficiency: In treadmill tests, the researchers have found that the robot — about the size and weight of an actual cheetah — wastes very little energy as it trots continuously for up to an hour and a half at 5 mph. The key to the robot’s streamlined stride: lightweight electric motors, set into its shoulders, that produce high torque with very little heat wasted.

The motors can be programmed to quickly adjust the robot’s leg stiffness and damping ratio — or cushioning — in response to outside forces such as a push, or a change in terrain. The researchers will present the efficiency results and design principles for their electric motor at the International Conference on Robotics and Automation in May.

Sangbae Kim, the Esther and Harold E. Edgerton Assistant Professor in MIT’s Department of Mechanical Engineering, says achieving energy-efficiency in legged robots has proven extremely difficult. Robots such as Boston Dynamic’s “Big Dog” carry heavy gasoline engines and hydraulic transmissions, while other electrically powered robots require large battery packs, gears, force sensors and springs to coordinate the joints in a robot’s leg. All this weighty machinery can add up to significant wasted energy, particularly when a robot’s legs need to make frequent contact with the ground in order to trot or gallop.

“In order to send a robot to find people or perform emergency tasks, like in the Fukushima disaster, you want it to be autonomous,” Kim says. “If it could run for more than two hours and search a large field, that would be useful. But one of the reasons why people think it’s impossible to make an electric robot that does this is because efficiencies have been pretty bad.”

Kim adds that part of the challenge in powering running machines with electric motors is that such robots require a flexible response upon impact, and high power, torque and efficiency — characteristics that have historically been difficult to achieve with electric motors.

To understand how an electrically powered system might waste little energy while running, the researchers first looked at general sources of energy loss in running robots. They found that most wasted energy comes from three sources: heat given off by a motor; energy dissipated through mechanical transmission, such as losses to friction through multiple gear trains; and inefficient control, such as energy lost through a heavy-footed step, as opposed to a smoother and more gentle gait.

The group then came up with design principles to minimize such energy waste. To combat heat loss from motors, the group proposed a high-torque-density motor — a motor that produces a significant amount of torque at a given weight and heat production. The team analyzed the relationship between motor size and torque, and designed custom motors that exceed the torque performance of commercially available electric motors.

The team found that such high-torque motors require fewer gears — a characteristic that would improve efficiency even more, as there would be less machinery through which energy could dissipate. Many researchers have used springs and dampers in series with motors to protect the robot from forceful impacts during locomotion, but it’s difficult to control a spring’s stiffness and damping ratio — which can be a problem if a robot has to traverse disparate surfaces, such as asphalt and sand.

“With our system, we can make our robotic leg behave like a spring or damper without having physical springs, dampers or force sensors,” Kim says.

Kim is the Esther and Harold E. Edgerton Assistant Professor in MIT’s Department of Mechanical Engineering. Photo: M. Scott Brauer

In addition to heat given off by a motor, the group found that another major source of energy loss comes from the force of impact as a robot’s leg hits the ground. Such forces can be strong enough to shake a machine and potentially cause damage. Engineers need to use dampers, or shock absorbers, to minimize shaking and stabilize such systems. But Kim says such dampers act to dissipate energy each time a leg meets the ground.

In contrast, the cheetah-bot’s electric motors capture this energy, feeding it back to the system to further power the robot.

“The majority of impact energy goes back to the battery because the damping is created by custom-designed electric control of the motor,” Kim says. “[The motor] regenerates energy that would have been lost.”

Kim adds that mounting motors and gears at the hip joint would also reduce energy loss by minimizing leg inertia: Some legged robots are designed with motors and gearboxes at each joint along a leg, which can be cumbersome and can lose more energy at every impact. With Kim’s design, 85 percent of the weight of the leg is concentrated at the hip joint, keeping the rest of the leg relatively lightweight.

The researchers also attached strips of Kevlar to connect sections of the robot’s legs, simulating the structure of tendons along a bone. The Kevlar strengthens the leg with little additional weight, and further reduces the leg’s inertia. The group also constructed a flexible spine out of rings of polyurethane rubber, sandwiched between vertebra-like segments. Kim hypothesizes that the spine moves along with the rear legs, and can store elastic energy while galloping.

To test the efficiency of the robot, the researchers ran it on a treadmill at a steady 5-mph clip. They measured the voltage and current of the battery, as well as that from each motor. They calculated the robot’s efficiency of locomotion — also known as cost of transport — and found that it was more efficient than robotic competitors such as Big Dog and Honda’s two-legged robot, ASIMO.

After digging through the literature on animal locomotion, the researchers plotted the cost of transport of various running, flying and swimming animals. They found that, not surprisingly, fliers were more efficient than runners, although swimmers were the most efficient movers. The cheetah robot, according to Kim’s calculations, falls around the efficiency range of humans, cheetahs and hunting dogs.

Currently the team is assembling a set of new motors, designed by Jeffrey Lang, a professor of electrical engineering at MIT. Kim expects that once the group outfits the robot with improved motors, the cheetah robot will be able to gallop at speeds of up to 35 mph, with an efficiency that rivals even fliers. The researchers are convinced that this approach can exceed biological muscle in many aspects, including power, torque and responsiveness.

“There are so many ways to design, and each legged robot has a different system,” Kim says. “If you design the motor properly, it’s more powerful, simpler robotics.”

Ron Fearing, a professor of electrical engineering and computer science at the University of California at Berkeley, says that simple springs can work well in small robots running on smooth terrain. But for rougher, more unpredictable terrain, he says the energy-recovery system of the MIT cheetah has big advantages.

“The cheetah robot has really pushed the technology in efficient motor design, low-loss transmissions, and low-inertia legs,” says Fearing, who did not contribute to the research. “By combining these with the regenerative motor drive system, so that mechanical energy from the leg can recharge the battery, that in my opinion has made a huge difference in efficiency, [and] an important step forward in making efficient, electrically driven running robots.”

In addition to Kim and Lang, the paper’s co-authors include Sangok Seok, Albert Wang, Meng Yee Chuah and David Otten, all of MIT.

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Op dinsdag 12 maart 2013 09:10 schreef ExperimentalFrentalMental het volgende:
11-03-2013

Ook robots beschikken nu over hun eigen internet

[ afbeelding ]

Wanneer wij iets niet weten, zoeken we het op op het internet. En nu kunnen robots hetzelfde doen. Onderzoekers hebben een internet voor robots gecreëerd waar onze stalen vrienden informatie op kwijt kunnen en informatie af kunnen halen.

Robots komen we nu al op tal van plekken tegen. Een mooi voorbeeld zijn de robots die geheel zelfstandig ons huis stofzuigen. De robots zijn al tot heel wat in staat: zo weten ze precies welk stukje van het huis ze al gestofzuigd hebben en welk deel ze nog moeten doen. Ook niet onbelangrijk: de robotstofzuigers weten ook wanneer ze zich moeten opladen en doen dat vervolgens zelfstandig. Het is indrukwekkend, maar dit zijn eigenlijk nog maar hele simpele robots die simpele taken uitvoeren.

Intelligenter
In de toekomst willen onderzoeker robots gaan ontwikkelen die veel meer kunnen. Bijvoorbeeld robots die ons eten kunnen bereiden en het bij ons kunnen brengen. Maar hoe ingewikkelder de robot, hoe meer geheugen en computerkracht deze ook nodig heeft. Daarom zullen deze robots zwaar en duur zijn en niet zo snel op grote schaal geproduceerd en gebruikt gaan worden. Om dat te voorkomen, hebben onderzoekers nu een internet voor robots ontwikkeld.

In de cloud
Het internet heeft verschillende functies. Zo stelt het robots in staat om een deel van hun verwerkingsprocessen in de cloud te doen. Dat betekent dat ze lokaal niet meer zoveel geheugen nodig hebben en informatie toch supersnel (vaak zelfs sneller dan met een lokaal geheugen) kunnen verwerken.

Leren
Maar het internet biedt robots ook de gelegenheid om van elkaar te leren en informatie met elkaar te delen. Zo kan een robotstofzuiger bijvoorbeeld een kaart maken van de woonkamer die een andere robot vervolgens weer kan gebruiken wanneer deze door de kamer wandelt om zijn huisgenoten ontbijt te brengen. Robots hoeven dus niet elke keer opnieuw het wiel uit te vinden. In plaats daarvan bouwen ze op de informatie die hun ‘collega’s’ reeds hebben verzameld, zo stellen de onderzoekers in hun paper.

De onderzoekers verwachten dat robots dankzij hun eigen internet lichter, goedkoper en intelligenter worden. Ze hebben het internet voor robots de naam Rapyuta gegeven

Rapyuta: The RoboEarth Cloud Engine

(scientias.nl)

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Op woensdag 13 maart 2013 23:47 schreef Dale. het volgende:

[..]

De professor die min of meer de leiding heeft over dit project krijgt soms van die mailtjes van die gekken die denken dat we skynet aan het oprichten zijn en bedreigen hem dan

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Op zondag 31 maart 2013 16:22 schreef Digi2 het volgende:
libelle-copter

Festo - BionicOpter

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Op zaterdag 6 april 2013 00:17 schreef Dale. het volgende:

Petman Tests Camo

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Op zaterdag 6 april 2013 00:17 schreef Dale. het volgende:

Petman Tests Camo

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The difference between people and machine will blur as we trek through the decades ahead.


As we move into the late 2030s and 2040s, the most salient scenario is that we will merge with our technology gradually, not overnight. We may not experience a single great leap like a “Singularity;” instead, we could see many small steps as we slowly become more machine-like.

AI/Robots will eventually surpass human levels of intelligence and develop ability to self-replicate, increasing intelligence with each succeeding generation. This will produce an information explosion almost beyond imagination.

Our bodies will also evolve during this time. We will use nanobots to kill pathogens and cancer cells, then go into our brain and do benign things like enhance memory. Slowly, these nanobots will become more sophisticated.

We will direct these ‘smart bots’ to convert biological neurons into powerful non-biological ones, and rewrite our brain’s ‘software’. This will allow us to connect with machines and share their super-intelligence.

Eventually, every cell in our body will become non-biological, and our silicon-based minds will not only be able to interface seamlessly with machines, but will also easily connect with one another utilizing thought communications.

As robots develop new abilities, we will incorporate those abilities into our makeup. As the years unfold, we will become more machine-like and robots more human-like, the difference between human and machine will blur.

By century’s end, the merge could be complete; we would become a single species. And although our minds and bodies will be considered non-biological, our consciousness will forever preserve our definition as a human being.

The journey into this human-machine future will take place one benign, safe change at a time, beginning in late 2030s and ending sometime during the last half of this century.

Are you ready to live in a ‘cyborg’ world? I’ll admit it would certainly take some getting used to, but should this octogenarian writer survive the decades ahead; I say welcome to our human-machine future!