New Breakthroughs In Robotics
For years, the IC industry has been looking at robotics as a big driver for chips. Robotics is still in its infancy and the technology remains a tiny part of the semiconductor industry.
One company, iRobot, has garnered attention with its vacuum cleaning robots. In fact, the company recently launched the Looj gutter cleaning robot and new Roomba 600 Series vacuum cleaning robots.
The Defense Advanced Research Projects Agency (DARPA) also is developing robots for military applications, including robotic “pack mule” prototypes, a Cheetah robot and silicone robots.
To help in emergency responses, humanitarian assistance and defense missions, robots need to negotiate over difficult terrain at suitable speeds. DARPA has just demonstrated two “pack mule” robot prototypes, dubbed the Legged Squad Support System (LS3). LS3 is a program that hopes to devise mobile, semi-autonomous legged robots that can carry 400 pounds and follow soldiers through rugged terrain.
Mechanical mule prototype. Source: DARPA
A two-year, platform-refinement test cycle began in 2012, with Marine and Army involvement. The recent LS3 demonstration included trotting, jogging, mobility runs and perception visualization. The LS3 is devised by Boston Dynamics of Waltham, Mass.
“We’ve refined the LS3 platform and have begun field testing against requirements of the Marine Corps,” said Army Lt. Col. Joe Hitt, DARPA program manager, on the DARPA site. “The vision for LS3 is to combine the capabilities of a pack mule with the intelligence of a trained animal.”
The demo also exhibited reduced noise levels for the robots. “LS3 is now roughly 10 times quieter than when the platform first came online, so squad members can carry on a conversation right next to it, which was difficult before,” Hitt said.
“Other improvements include the ability to go from a 1- to 3-mph walk and trot over rough, rocky terrain, easily transition to a 5-mph jog and, eventually, a 7-mph run over flat surfaces, showing the versatility needed to accompany dismounted units in various terrains,” Hitt said. “The LS3 has demonstrated it is very stable on its legs, but if it should tip over for some reason, it can automatically right itself, stand up and carry on. LS3 also has the ability to follow a human leader and track members of a squad in forested terrain and high brush.”
In another development, DARPA recently updated its so-called Cheetah robot. Cheetah recently broke its own land speed record of 18 miles per hour and was clocked at 28.3 mph for a 20-meter split. This makes the robot faster than Jamaican sprinter Usain Bolt. According to the International Association of Athletics Federations, Bolt set the world speed record for a human in 2009 when he reached a peak speed of 27.78 mph for a 20-meter split during the 100-meter sprint.
Cheetah is being developed and tested under DARPA’s Maximum Mobility and Manipulation (M3) program by Boston Dynamics. DARPA intends to test a prototype on natural terrain next year. Cheetah currently runs on a treadmill in a lab.
The current version of the Cheetah robot is powered by an off-board hydraulic pump. “What DARPA is doing with its robotics programs is attempting to understand and engineer into robots certain core capabilities that living organisms have refined over a millennia of evolution: efficient locomotion, manipulation of objects and adaptability to environments,” said Gill Pratt, DARPA program manager, on DARPA’s site. “What we gain through Cheetah and related research efforts are technological building blocks that create possibilities for a whole range of robots suited to future Department of Defense missions.”
DARPA also foresees robots of many shapes and sizes contributing to a wide range of future defense missions. Not to be outdone, researchers have devised a robot made of silicone. It can walk, change color and light up in the dark at less than $100.
Harvard University and the Wyss Institute for Biologically Inspired Engineering have demonstrated soft robots with microfluidic channels. Soft robots can perform several functions, such as actuation, camouflage, display, fluid transport and temperature regulation. The work is being performed under DARPA’s M3 program.
Researchers used tethers to attach the control system and pump pressurized gases and liquids into the robot. At a pumping rate of 2.25 milliliters per minute, color change in the robot required 30 seconds. Once filled, the color layers require no power to sustain the color.
Glass-Blown 3D Sensors
The military relies on global positioning system (GPS) technology and sensors for navigation. Sensors, namely gyroscopes, are bulky and expensive to make. A gyroscope designed as an inertial sensor accurate enough for a missile can take up to one month to assemble and cost up to $1 million, according to DARPA.
In a phase 1 portion of a project, DARPA is developing new 3D fabrication techniques for devising microscale inertial sensors, based on traditional glass blowing and atomic layering of diamond. The final goal of the phase 2 portion is to demonstrate an integrating gyroscope. “These new fabrication methods were thought to be unrealistic just a few years ago,” said Andrei Shkel, DARPA program manager, on DARPA’s site. “Phase 2 has kicked off, in which DARPA seeks to hone these methods to create and demonstrate operational devices.”
The idea is to replace expensive gyroscopes with devices that resemble Foucault pendulums. These types of devices consist of a tall pendulum, which swings in any vertical plane. But instead of a swinging pendulum, microscale inertial sensors send out vibrations across the surface of a 3D structure. The waves are measured and any changes reflect a change in orientation, according to DARPA.
To make microscale inertial sensors, DARPA is looking at three fabrication methods: traditional glass blowing, quartz blowing and atomic layering of diamond. Traditional glass-blowing techniques resulted in the development of tiny 3D wineglass-shaped inertial sensors, which have a frequency split approaching 10Hz. Frequency split is a measure to predict the symmetry and accuracy of a device.
DARPA also developed quartz blowing fabrication techniques needed to heat quartz to 1,700 degrees Celsius and to then cool it rapidly. The fabrication technique is used to make symmetric structures. Finally, layering diamond over a blown structure or depositing CVD diamond in a micro-well on the substrate enables symmetric, accurate 3D inertial-sensor structures.
The phase 2 process hopes to make these devices more accurate and reliable by reducing frequency split from 10 Hz to 5 Hz, increasing decay times from 10 seconds to 100 seconds, and decreasing volume from 20mm3 to 10mm3. “As work continues, DARPA hopes these new technologies will enable large-scale production of navigation-grade microscale inertial sensors,” added Shkel. “Production of 3D inertial sensors with these new techniques would cost about the same as today’s integrated circuit, making them orders of magnitude smaller, cheaper and more capable than current microgyroscopes.”
Chemical Lift-Off Lithography To Pattern Molecules
UCLA has developed a new process called chemical lift-off lithography (CLL), which is said to pattern biomolecules at high resolutions.
The technology solves a major problem. Traditionally, the way to pattern biomolecules has been a method that resembles nanoimprint lithography. Tiny stamps are devised and covered with molecular “inks,” thereby creating molecular patterns. But this technique tends to diffuse on the surface both during and after stamping, which blurs the patterns.
To address this problem, UCLA has devised a “soft lithography” process called CLL. CLL also resembles nanoimprint lithography. In CLL, UCLA uses chemically treated stamps to remove molecules already in place on gold substrates. This, in turn, peels away select molecules through chemical bonds to create patterns.
Reactive stamps remove molecules from surfaces to create precise nanoscale patterns. Source: UCLA
UCLA has developed a “subtractive” stamping process in which silicone rubber stamps, activated by oxygen plasma, selectively remove hydroxyl-terminated alkanethiols from self-assembled monolayers (SAMs) on gold surfaces with high pattern fidelity. Monolayer backfilling into the lift-off areas enabled patterned protein capture, and 40nm chemical patterns were achieved, according to UCLA.
New Epitaxial Materials
Epitaxial thin films are created by growing a crystal layer of one material on another. The goal is to get the structures to align. But the issue is to grow the film coherently with minimal defects.
Oak Ridge National Laboratory has discovered a path toward defect-free thin films. It discovered a strain relaxation phenomenon in cobaltites. Cobaltite is a sulfosalt mineral composed of cobalt, arsenic and sulfur.
Researchers were able to devise cobaltite with structurally atomic patterns. The material can change its magnetic properties and minimize the size mismatch with a crystalline substrate. It also could lead to new advances in fuel cells, magnetic sensors and other materials.
The finding changes the conventional wisdom that accommodating the strain inherent during the formation of epitaxial thin films necessarily involves structural defects. Using scanning transmission electron microscopy complemented by X-ray and optical spectroscopy, researchers could see unconventional strain relaxation behavior that produced stripe-like lattice patterns.
“We discovered properties that were not readily apparent in crystal, or bulk form, but in thin-film form we were able to clearly see the atomically ordered lattice structure of lanthanum cobaltite,” said Ho Nyung Lee, a member of the Department of Energy lab’s Materials Science and Technology Division. “With this knowledge, we hope to be able to tailor the physical properties of a material for many information and energy technologies.”