Biologically inspired robots are being realized by engineers and scientists all over the world. While much emphasis is placed on developing physical characteristics for robots such as human-like faces or artificial muscles, engineers in the Telerobotics Research and Applications Group at NASA’s Jet Propulsion Laboratory in Pasadena, CA, are among those working to program robots with forms of artificial intelligence similar to human thinking processes.
“The way robots function now, if something goes wrong, humans modify their programming code and reload everything, then hope it eventually works,” said JPL robotics engineer Barry Werger. “What we hope to do eventually is get robots to be more independent and learn to adjust their own programming.”
Scientists and engineers take several approaches to control robots. The two extreme ends of the spectrum are called “deliberative control” and “reactive control.” The former is the traditional, dominant way in which robots function, by painstakingly constructing maps and other types of models that they use to plan sequences of action with mathematical precision. The robot performs these sequences like reading a treasure map: from point A, move 36 paces north, then 12 paces east, then 4 paces northeast to point X.
The downside to this is that if anything interrupts the robot’s progress (for example, if the map is wrong or lacks detail), the robot must stop and make a new map and a new plan of action. This re-planning process can become costly if repeated over time. Also, to ensure the robot’s safety, back-up programs must be in place to abort the plan if the robot encounters an unforeseen rock or hole that may hinder its journey.
“Reactive” approaches, on the other hand, get rid of maps and planning altogether and focus on live observation of the environment: slow down if there’s a rock ahead, dig if you see a big X on the ground.
The JPL Telerobotics Research and Applications Group, led by technical group supervisor Dr. Homayoun Seraji, focuses on “behavior-based control,” which lies toward the “reactive” end of the spectrum. Behavior-based control allows robots to follow a plan while staying aware of the unexpected, changing features of their environment: turn right when you see a red rock, go all the way down the hill, and dig right next to the palm tree.
Behavior-based control allows the robot a great deal of flexibility to adapt the plan to its environment as it goes, much as a human does. This presents a number of advantages in space exploration, including alleviating the communication delay that results from operating distant rovers from Earth.
In space, extending the human touch — be it in low Earth orbit or to the Moon, Mars, and asteroids — is bolstered by a fusion of astronaut and robot skills.
“We’re working on human robotic systems — not either or, but robots that make a crew more effective,” said Bill Bluethmann at NASA’s Johnson Space Center (JSC) in Houston, TX. Ap p roaching 25 years of robotics work, Bluethmann is the Human Robotic Systems Project Manag er at JSC.
NASA’s Office of the Chief Technologist is cultivating new sets of human robotics systems under its Space Technology Program. As Bluethmann pointed out, “A big part of that is doing in-space work,” such as designing lengthy robot arms that can stretch out and grapple an asteroid.
“Giving astronauts a ‘finesse factor’ to safely work around a space object demands different approaches, given an asteroid’s microgravity condition,” Bluethmann said. “Making use of a robotic arm to anchor a piloted excursion vehicle to an asteroid is under study, as is positioning an astronaut over the asteroid to enable up-close-and-personal study.”
Leading-edge custom motors and motion control technology are enabling factors in tightly packaging robotic arms. “We’re able to embed a lot of smarts in the joints,” Bluethmann ex plain ed, “rather than running long and heavy wires back to some central spot.”