September 1st, 2008
Follow that robot!
Three years after the development of robots that act like rats, UC Davis engineers have designed a control system for robots allowing them to pick up on cues that the leader is about to turn, predict where it is going and follow it. This system mimics the human ability to capture signals — consciously or not — from drivers on the road or people walking in the streets to predict what they’re about to do. As said the team leader, ‘robots that are better at following could be easier for people to work with.’ With this system, an hospital robot could follow doctors during their rounds. The researchers don’t say anything about the availability of their system, but read more…
You can see above a robot following its leader. (Credit: UC Davis) Here is a link to a larger version of this photo. And here is a link to more information and other pictures of the commercially available robot used by the team, the ERSP Scorpion Robot from Evolution Robotics.
The research team was led by Sanjay Joshi, an assistant professor in the Department of Mechanical and Aeronautical Engineering at UC Davis. For this project, he worked with graduate student Michael Chueh, and undergraduate students William Au Yeung and Calvin Lei.
So how does this control system work? “The robot’s camera could identify a target on the lead robot, and the robot’s onboard computer could combine the target information with behavioral cue information. Rather than have the lead robot signal the follower directly, the research team sent ‘behavioral cues’ to the follower via wireless link. Effectively, the cues told the robot, ‘the leader might be about to turn right’ or ‘might be about to turn left.’ To develop a decision on how to move, the follower robot was programmed to take into account the lead robot’s behavioral cues and the follower’s prediction of the lead robot’s movement, based on the leader’s current speed and direction. Robots that incorporated behavioral information into their decisions performed much better at following the leader around corners than others, the researchers found.”
An article from PhysOrg.com, “Robots Detect Behavioral Cues to Follow Humans,” gives some additional details. Here is a quote from what Joshi said to PhysOrg.com. “As humans, we constantly incorporate other peoples’ current actions as clues (cues) as to what they may do in the future. For instance, we have a ’sixth sense’ on the highway to know that a certain car will swerve into our lane soon, based on the driver’s current driving patterns. Then, we may become more defensive in our own driving. In our work, we wanted to begin the process of allowing robots to use behavioral cues (of humans or other robots), to make the robot’s mission more reliable and accurate. In social work environments populated by numerous people and robots, these types of cues should be abundant.”
This research work has been published in the August 2008 issue of IEEE Transactions on Industrial Electronics under the name “Following Controller for Autonomous Mobile Robots Using Behavioral Cues” (Volume 55, Number 8, Pages 3124-3132).
Here is the beginning of the abstract. “This paper proposes an autonomous-robot following controller that can integrate information provided from behavioral cues of the leader to increase the reliability and the performance of following. The controller continuously estimates the future predicted position of the leader as it moves, and then directs the follower robot to this position. A Kalman filter is employed for an estimation that uses vision-based measurements of leader position, a dynamic model of the leader, and a behavioral-cue model of the leader. The behavioral-cue model serves to either tune the dynamic model and/or create pseudomeasurements to further help the Kalman filter estimate the leader’s future position. Once the leader’s future position is estimated, a trajectory planner plans a path to the future position, and a motor controller implements the required control signals to the robot wheels.”
Sources: UC Davis News, August 28, 2008; and various websites
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