Robot With Laser Eyes Takes Lumbering First Step (1985)

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October 15, 1985By MALCOLM W. BROWNEWITH a blast of exhaust smoke and an ear-splitting howl, a three-ton robot came to life in a workshop at Ohio State University last week, tentatively flexing the hydraulic muscles of one of its six elephantine legs and practicing the movements that will eventually enable it to walk.The great limb, powerful enough to crush an automobile but gentle enough to manipulate a fragile cardboard box, merely took a few dummy strides in its latest series of tests. But the builders of Ohio State's Adaptive Suspension Vehicle (A.S.V.) believe their robot creature -the product of $5 million and nearly two decades of research and development - is nearly ready to lumber out of the laboratory.The project has always been regarded by its directors as a research exercise for developing the theory of robotics, and in the early years, financial support came mainly from the National Science Foundation. But because a large walking robot has obvious military potential, the Defense Department has been the main supporter of the project since 1980.Controlled partly by a battery of computers and partly by a human driver, the A.S.V. will walk as no machine has ever walked before.As large as a dinosaur but with the agility and balance of a crab or insect, the walker will maneuver through forests, bogs and desert sand, up and down steep hills, across ditches up to nine feet wide and over obstacles up to seven feet high. Scanning its path with infrared laser ''eyes,'' the 17-foot-long machine will plan each step it takes, looking for footholds, avoiding holes and making the best of whatever terrain it has to cover.Vision is not the only sense with which the robot has been endowed. Like a bat, it will use acoustic echoes to gauge the proximity of neighboring objects. Pressure sensors in the machine's footpads will constantly inform its computer brain of the nature of the ground it is covering, and a gyroscopic balance sensor will serve the same purpose as an animal's vestibular system. All in all, Ohio State's mechanical beast is expected to be as sure-footed as a camel, stronger than an elephant and a good deal smarter than the insects on whose mode of locomotion it is partly based.No Mere MachineTo the Ohio State professors Robert B. McGhee and Kenneth J. Waldron, who have devoted large parts of their careers to the A.S.V. and its antecedents, the six-legged walker is no mere machine; it is the embodiment of discoveries that have significantly advanced the fields of robotics, computer control, biology, anatomy and even medicine. Systems developed for use in robot walking machines have found important applications in prosthetic limbs for human patients.Nonetheless, the A.S.V. may be the precursor of a family of machines so interesting to the Defense Department that the project is now financed by the Defense Advanced Research Projects Agency (Darpa).''The Army has estimated that about 50 percent of the earth's land surface is inaccessible to all conventional vehicles, whether they run on wheels or tracks,'' Dr. McGhee said in an interview, ''That's one of the reasons the armed forces are interested in the A.S.V. - a vehicle that can walk anywhere.'' #70-Horsepower Engine Unlike early experimental walking machines, this one is built for rough field use, carrying its own motor and accessories. Motive force for the A.S.V. is supplied by a 70-horsepower motorcycle engine whose energy is stored by spinning a 100-pound flywheel to a speed of more than 12,000 revolutions per minute. The flywheel, in turn, powers a score of hydraulic actuators that move the various joints of each of the machine's legs. The vehicle's top speed will be only eight miles an hour, but it was not designed to compete with race horses.Such a machine could go where the nimblest tank or off-road vehicle would bog down. Moreover, it could be adapted to move and fight on its own, without a human driver or crew. Current Darpa-financed research at Ohio State and Carnegie-Mellon University, Martin Marietta Aerospace and other institutions seeks to perfect the computer programs and hardware needed to make a vehicle fully ''autonomous'' -capable of running cross-country or along roads without human aid.Dr. McGhee envisions many nonmilitary uses for walkers. In arctic tundra, where tractor treads cause irreparable damage to local plant life, mechanical legs would provide the least harmful form of traction, he said. Walkers could also replace less maneuverable robots working in such hazardous environments as the interior of nuclear reactors.Machines in Russia and JapanImprovements in the computer technology of the Soviet Union have led to important advances in Soviet walking machines, Dr. McGhee said, and walkers are also being built in Japan, Switzerland and Liechtenstein. An eight-legged, 70-ton monster manufactured by Japan's Komatsu Corporation has replaced 50 human divers in the construction of an underwater foundation for a seawall, he said. Other Japanese companies are considering the development of walking machines as recreational off-road vehicles.None of these machines, however, has the intelligence or lifelike system of locomotion built into the A.S.V., nor do their technologies draw from so many different fields of scientific endeavor.Defense Department money allocated to the walking-machine project has financed some startlingly nonmilitary research along the way. Under a Darpa subcontract let by Ohio State University, for instance, physiologists and biologists at the University of Alberta, Canada, have studied the coordination of leg movements in locusts. Because insects were regarded as especially good walkers, scientists hoped to apply their studies of insect physiology to the design of mechanical walkers.As it turned out, some of nature's models proved less efficient than the scientists had expected. The locust, for example, is apparently unable to benefit from experience. If one of a locust's forelegs encounters empty space where the insect expects to find solid ground, the leg flails around until it finds a suitable foothold. One might assume that when another of the insect's legs arrived at the same spot, experience would guide it immediately to a safe foothold. But such is not the case; the leg gropes anew for a foothold, its owner's feeble brain apparently having learned nothing from the previous search.Computer Guidance SystemLeg-movement coordination in many insects is also surprisingly poor, according to Vincent J. Vohnout, one of the engineers working on the A.S.V. ''One of an insect's legs will often collide with another of its legs,'' he said. ''If we were to let that happen on the A.S.V. walker, the machine would quickly demolish itself, of course. The computer guidance system of the A.S.V. prohibits any movement that would damage the machine or its human driver. When I first started on this project I had to interest myself in the way cockroaches walk, but I've come to realize that insect locomotion systems are far from ideal, from our standpoint.''Close scientific inspection reveals that the seemingly agile grasshopper frequently trips over its own legs and falls on its belly; it is forced to drag itself awkwardly along while regaining its standing posture. Turtles, which sometimes walk but which usually crawl on their bellies, have also been dismissed by engineers as inappropriate models for machine analogs. Under a new Darpa subcontract, however, scientists will seek useful pointers from the locomotion of goats, which are among the best of all mammalian walkers.A six-legged animal or machine, said Dr. McGhee, is theoretically capable of several million different gaits, each of which differs from the others in the sequence and timing of leg movements. But careful mathematical analysis of all these gaits has shown that only a half-dozen of them combine efficient locomotion with optimal stability, he said.The selection by an animal of one or another gait depends mainly on the speed at which it will travel. (When a six-legged animal moves at slow speed, for instance, it may use a gait in which three feet move at a time, leaving the other three feet to support the animal in tripod fashion. At higher speeds, the animal may sacrifice the static stability of the tripod in exchange for dynamic stability afforded by rapid motion.) Some Bewildering Problems The selection of efficient gaits for the A.S.V. and the coordination of the machine's hundred or so control variables have created problems of bewildering complexity for the 16 powerful Intel computers the vehicle carries in its aluminum belly. But most of the solutions are either in hand or in sight, the builders believe.''Two decades ago,'' Dr. McGhee said, ''I realized that a walking machine under autonomous electronic control would require a very high order of computing power. At the time, no computers existed that could do the job. But today the goal is within reach. As we develop artificial intelligence - the so-called Fifth Generation of computer capability -progress will be still more dramatic.''Dr. McGhee and 64 colleagues working on the A.S.V. project regard their walker as a proof-of-concept device, not as a military or industrial prototype. ''The creation of real prototypes is a task for industry, not for us,'' Dr. McGhee said.But with many more challenges to meet (and currently backed by an annual budget of $2 million), the group foresees a long and fruitful future for their project. Laboratory development of the A.S.V. should be completed a year from now, after which the machine will undergo field development.At first, a human driver will control the higher functions of the machine. The driver's cockpit contains a stick similar in form to the control stick used in airplanes. By moving it forward or backward, the driver controls forward and reverse speed. Movements from side to side cause the vehicle to move crabwise, twisting the stick makes the vehicle turn in place, and buttons on the stick control attitude and the height of the machine's body above the ground. The driver can override the computer's control of individual leg movements, but since these operations are so complex and difficult, he would rarely choose to take them on.Improved Model Is PlannedIn future years, the group intends to field a version of the walker so improved that it would perform tasks entirely automatically, with no driver aboard. The radar-like data sent to on-board computers by the A.S.V.'s scanning infrared laser beam will enable the machine not only to steer and maneuver itself, but to carry out a programmed sequence of actions, its developers say.Further in the future, Dr. McGhee hopes to eliminate the middle pair of legs from the machine, transforming it into something Darpa calls an Agile Autonomous Vehicle (A.A.V.).''When we started working on walkers, I drew some inspiration from my daughter's horses,'' Dr. McGhee said. ''Quadrupedal animals are much more agile than hexapods (six-legged ones), and that fact led us during the 1970's to build a four-legged machine we called the Phony Pony. Unfortunately, four-legged machines have to solve balancing problems that are far more difficult than comparable problems in hexapods, and we finally gave up on the Phony Pony.''But advances in our research will eventually make the four-legged walker feasible. For expert walking ability, it's hard to match the horses, mules and goats. But the A.A.V. we intend to build is going to come close,'' he said.http://www.nytimes.com/1985/10/15/science/robot-with-laser-eyes-takes-lumbering-first-step.html