CMU roboticists develop CHIMP for DARPA challenge

The CHIMP robot was created to help in emergency situations, such as the Fukushima nuclear crisis. (credit: Courtesy of Carnegie Mellon University Tartan Rescue) The CHIMP robot was created to help in emergency situations, such as the Fukushima nuclear crisis. (credit: Courtesy of Carnegie Mellon University Tartan Rescue)

The Defense Advanced Research Project Agency (DARPA)’s robotics challenge has been pushing scientists to create robots that surpass any they have developed thus far. Tartan Rescue Team, a team from Carnegie Mellon’s National Robotics Engineering Center (NREC), is developing the CMU Highly Intelligent Mobile Platform (CHIMP) robot to compete in the challenge.

DARPA created the robotics challenge in response to the Fukushima Daiichi nuclear crisis, in which dangerous and health-threatening conditions prevented an effective human response. After the nuclear crisis, robots were not capable of properly dealing with the disaster. DARPA aims to promote the improvement of robotics technology to develop robots that can efficiently “work in dangerous, degraded, human-engineered environments,” according to the Tartan Rescue website.

Toward this end, the Tartan Rescue Team is engineering a class of robot that integrates robot autonomy with human control. This approach entails that a human controller would make high-level decisions for the robot, such as determining the path it takes, while the robot would have enough capability to avoid sudden collisions and maintain stability.

The team members include Siddharta Srinivasa, David Stager, Eric Meyhofer, Bryan Salesky, Alonzo Kelly, Maxim Likhachev, Clark Haynes, Herman Herman, and Drew Bagnell — all of whom are affiliated with NREC or the Robotics Institute. The team’s sponsors include Kollmorgen, OshKosh, Pratt & Miller, and Honeywell, among others.

“The CHIMP robot has sensors, such as cameras and laser rangefinders, in its head and limbs to detect obstacles in the environment and to stop the robot before a collision occurs,” explained Tony Stentz, Tartan Rescue Team leader and NREC director. The robot is also intelligent enough to perform simple tasks, such as stepping onto rungs of ladders or turning steering wheels, without needing step-by-step control. The “supervised autonomy” method allows for a highly capable robot without the risk of technical difficulties and complications that could result from a fully autonomous robot.
“The primary advantage of supervised autonomy is that it is easier to achieve than full autonomy. Supervised autonomy provides a way for a remote human operator to control the robot via high-level commands and to help it get out of trouble,” Stentz said.

In addition to practical integration of autonomy and human control, CHIMP has a number of innovative physical features that would make it the ideal candidate to respond to disasters such as the Fukushima crisis. “The CHIMP robot includes a number of technical advances in mechanism design, robot motion planning, perception-enabled grasping, advanced mobility, and multilimb manipulation,” Stentz said.

One such advantage, namely its ability to switch between moving on rubberized tracks and on two limbs, provides tremendous advantages for physical stability as well as programming efficiency. When moving over rough grounds or debris, CHIMP maneuvers itself on rubberized tracks located on all four of its limbs. Moving with all four limbs on the ground prevents the robot from losing balance, even during a period of power failure or technical difficulty. It also avoids the complex programming required to coordinate a robot that only moves on two limbs. However, in the event that the robot needs to perform a task such as using tools or climbing ladders, it is able to switch to maneuvering on two limbs.

For robots geared toward responding to crises similar to the Fukushima nuclear crisis, Stentz believes it is imperative to make the robot as autonomous as possible. “For disaster-response scenarios, the communication link from the human operator to the robot may be unreliable; therefore, it is important for the robot to be as autonomous as possible. There are many hard technical problems, but I would say that the perception, grasping, and manipulation tasks are the most difficult to conquer to achieve greater autonomy,” he explained.

As detailed on Tartan Rescue Team’s website, robots will be judged on capabilities that include opening doors, climbing ladders and navigating walkways, and breaking through concrete panels using tools. The robots will also be assesed on more specific criteria, such as finding and closing valves near leaking pipes, and replacing components like cooling pumps.
According to Stentz, if the team were to win the robotics challenge, the ideas incorporated in CHIMP would be used in future robots.