Above: Keith Clark demonstrates his design for an innovative end effector which would inflate inside, and so grip, a tubular truss structure.
Back in 1978, another type of end effector under study for the Space Shuttle's Remote Manipulator System (RMS) was actually a balloon. The sort of aluminium truss beams proposed for use in space construction are quite fragile, so Keith Clark of NASAs Marshall Space Flight Center has proposed using a balloon that would be inflated inside the beam. As it expanded it would press gently and "grasp" the beam, distributing the load across the beam rather than crushing on one or two points. Such a tool could easily be used to grapple anything that had an opening. The balloon would probably be a bladder coated with Kevlar to protect it against sunlight and punctures.
Pneumatic inflatable end effector Keith H. Clark et al
See full patent here.
Patent number: 4273505
Filing date: Sep 22, 1978
Issue date: Jun 16, 1981
A good example of the "big iron" approach to mobile robots is AMBLER (acronym for Autonomous MoBiLe Exploration Robot), developed by Carnegie Mellon University and the Jet Propulsion Laboratory. This behemoth stands about 5m (16.4ft) tall, is up to 7m (23.0ft) wide, and weights 2500 kg (5512 lb). It moves at a blistering 35 cm (13.8 in) per minute. Just sitting still, it consumes 1400 W of power. Ask it to walk and it sucks up just about 4000 W.
AMBLER showing time-lapse traces on one leg.
Some of the Carnegie-Mellon team with AMBLER highlight its immense size.
See a few pdf's describing AMBLER mainly here and here.
The Ambler robot was designed for walking under the particular constraints of planetary terrain, where there are meter-sized boulders, deep crevices, and steep slopes-an altogether inhospitable environment that defies humans and wheeled machines alike. Therefore, the six-legged Ambler travels over extremely rugged terrain without the close aid of humans. Autonomously, the Ambler builds detailed terrain maps; plans its own sequence and location of steps; and controls its movement, balance, and stability. In extensive tests, the Ambler has traveled thousands of meters, taken thousands of steps, and negotiated terrains that defy other robots.
Ambler walks like no other machine and like no other creature in nature: Stepping with any leg in any sequence, the Ambler has the patented capability to move its rear-most leg past all other legs in order to travel over extreme terrain as efficiently as possible. Also, while most animals bend their legs to step and walk, Ambler's legs remain vertical, while they swing horizontally, then lengthen themselves vertically, like a telescope, to touch the ground. Such legs do not rock or sway in the act of stepping, thus risking unnecessary collision with obstacles. More flexible, animal-like legs require substantially more sensing and planning from a robot, but the Ambler's unbendable legs decrease both the consequences and the extra planning that would be necessary for bendable legs.
The robot's height of 3.5 meters enables it to step over obstacles as high as one meter. At the same time, no matter how rough the terrain, the Ambler walks upright, keeping its legs vertical and its body horizontalÑand keeping its laser rangefinder steady. It is through data from the laser rangefinder that the Ambler's perception system builds computerized maps of the terrain. (See Terrain Mapping, Krotkov.) In fact, Ambler's walking design facilitates perception of the terrain by maintaining a steady and level posture (on a 30 degree slope). When the robotÕs perception system merges laser images from different viewpoints into a larger composite picture of the terrain, the robot's stability gives its laser images a good registrationÑthat is, leaves very little unintended overlap and no gaps between the various image viewpoints. The robot's height also gives the laser rangefinder a high-vantage with which to better view the terrain, and promotes a high quality of sensor data.
Although remote human operators tell the Ambler where to go, the robot itself plans the steps it must take to get there (see also, Gait Configuration of Legged Robots, Wettergreen). The robot's gait planner takes into account not only terrain constraints but also its own walking capabilities: how far the robot's legs can reach, how long the legs can extend, how far the robot's body can stray from its center of gravity, where the robot can move each leg without colliding into another leg, and how it can place its legs so that its body-which moves alternately with the legs-also has a clear path to move forward.
After the gait planner has intersected all of these constraints and determined a limited number of steps, the footfall planner considers which of the available steps offer the best footholds and are more efficient in time and energy. The footfall planner has learned, through a neural network, which footholds are optimal, having been presented examples during its development of good and bad footholds. The leg recovery planner finally determines how to move each leg without colliding into something mid-move. At the same time, the robot's planners must weigh the various constraints. For example, the robot's body must move as far forward as possible (to increase efficiency of speed), without moving beyond its center of gravity.
Getting the various on-board systems to interact efficiently involves the use of Task Control architecture (see Task-Level Communication and Control, Simmons). Like a switch-board operator, TCA facilitates communication between the Ambler's various systems, coordinates the robot's plans, sequences tasks, and monitors actions and recovers from problems. Task Control Architecture enables planning, perception, and real-time control to work concurrently.
Sweaty Manny by Arthur Fisher
Popular Science - Sep 1988
Manny. One of the most complex and sophisticated computer-controlled movable robots ever designed, as seen in the photos above, is being built at Battelle's Pacific Northwest Laboratories in Richland, Wash. "Manny," for robotic mannequin, is so humanlike that it even sweats.
"In its final form," says David W. Bennett of Battelle's Applied Physics Center, "the mannequin will physically resemble the human body in size and limb and trunk geometry. It will be capable of simulating complex body movements and poses, breathing, body and skin temperature, sweating…."
Why have a sweaty robot? Manny is being built for the U.S. Army's Dugway Proving Ground in Dugway, Utah, about 85 miles southwest of Salt Lake City. It will be used to test protective clothing in simulated conditions that are hazardous-maybe even hellish-for humans.
"Manny will test the effectiveness of clothing used to protect people from chemicals, temperature extremes, and other hostile environments," says Bennett. It could find a job, not just with the military, but also with industries the must develop and test products for use in a variety of hazardous situations: firefighting and working in nuclear reactors and toxic waste disposals come to mind.
Manny has about 40 articulated joints that accommodate motion and enable clothing under test to be stressed. Attached to its back is a support arm that helps the mannequin simulate walking, bending, squatting, and crawling in a prone position. hydraulic devices located in each joint power the robot's movements.
Manny's skeleton is formed of tubes and pivots, visible in the close-up photo of the arm and shoulder. The skeleton is covered (in the final version) with a flexible plastic skin.
And sweating? Perspiration is simulated by injecting water at several skin surface sites through an array of narrow tubes. Breathing-yes, Manny breathes too-is simulated by expansion and contraction of the chest and by injection of moist air at the nose and mouth to simulate lund inhalation and expiration.
Battelle engineers expect Manny to be fully operational this year.
SAM, a mobile manipulator, mimics the movements of an operator stationed at a far-distant control center.
The Self-propelled Anthropomorphic Manipulator (SAM) that wears NASA logos was developed under Edwin Johnson's direction in 1969 by the now defunct Space Nuclear Propulsion division of the U.S. Atomic Energy Commission. Johnson is credited with introducing the popular term "teleoperator" in 1966 to describe a servo controlled manipulator that is not directly connected to the operator's twin manipulator.
RISE OF THE ROBOTS – George Sullivan 1971
Government scientists representing the Space Nuclear Propulsion Office of the Atomic Energy Commission have taken the basic operational principles of the mobile manipulator and added an extra—long-distance control. The machine they've developed is one of the most exciting advances in teleoperator technology in recent years.
Nicknamed "SAM" ( for Self-propelled Anthropomorphic Manipulator), the unit is composed of two distinct parts. A machine portion features steel arms and hands, very similar to the arms and hands used in handling radioactive materials inside hot cells. These arms and hands, however, are mounted on a steel boom which moves up and down and in a circular pattern to give a wide range of operation. The boom, in turn, is mounted on an open, four-wheeled vehicle about the size of an Army jeep. This "torso" portion of the unit is topped with a small television camera. Its "eye" peers down at whatever the hands grasp. The second portion of the unit is the control station, the command post for the human operator. The control station and the mobile manipulator are linked by a coaxial cable, the same type of insulated conducting tube that is used to transmit television signals from a studio to viewers' homes. The two parts of the system can also be linked by radio control.
The operator wears a jacketlike apparatus called an "exoskeleton" to send commands to SAM's hands and arms. If the operator wants SAM to pick up a stick, he simply reaches down and performs the necessary hand-arm movements. The operator is able to see the stick by means of a television screen in the control center which presents the picture transmitted by SAM's television camera. Scientists plan to "slave" the movements of the television camera to those of the operator's head. The camera will thus become the operator's remote but all-seeing eye.
The first SAM was built at the Nuclear Rocket Development Station located at Jackass Flats, Nevada. It inspects and tests equipment used at radioactive nuclear test sites. It is planned that SAM-type units of the future will be used to defuse and dispose of dangerous bombs, and as search and rescue vehicles in any type of disaster that involves fire or hazardous fumes, not just those caused by nuclear explosion.
Machines such as SAM suggest a wide array of applications. Teleoperators could be put beneath the sea or on a distant planet and be made to perform a variety of chores, all while under the precise command of a human operator housed in the safety of an earthbound control center.
From an overhead view, SAM looks like this.
Using an exoskeleton and guided by what he sees on the television screen, the operator controls SAM with simple arm-hand movements.