Human/Robot Cross-Training Touted in MIT Study
"This is the first evidence that human-robot teamwork is improved when a human and robot train together by switching roles, in a manner similar to effective human team training practices," Ph.D. student Stefanos Nikolaidis said.
A paper to be presented at the International Conference on Human-Robot Interaction in Tokyo next month reports cross-training is an effective team-building tool when human beings and robots are working together, MIT News correspondent Helen Knight reports. The research was done by Julie Shah, an assistant professor of aeronautics and astronautics at MIT and head of the Interactive Robotics Group in the Computer Science and Artificial Intelligence Laboratory, and Ph.D. student Stefanos Nikolaidis.
"People aren't robots, they don't do things the same way every single time," Shah told Knight. "And so there is a mismatch between the way we program robots to perform tasks in exactly the same way each time and what we need them to do if they are going to work in concert with people."
They wanted to find out whether cross-training, an effective techniques for training people, also can work in mixed teams of humans and robots. This entailed creating a new algorithm so the robots could learn from their role-swapping experiences. "So they modified existing reinforcement-learning algorithms to allow the robots to take in not only information from positive and negative rewards, but also information gained through demonstration. In this way, by watching their human counterparts switch roles to carry out their work, the robots were able to learn how the humans wanted them to perform the same task," Knight reported. Each mixed team then performed a simulated task in a virtual environment, with half of the teams using the conventional interactive reward approach and half using cross-training and switching roles halfway through the session. The teams then did the task in the real world, but this time sticking to their own designated roles.
"Shah and Nikolaidis found that the period in which human and robot were working at the same time — known as concurrent motion — increased by 71 percent in teams that had taken part in cross-training, compared to the interactive reward teams. They also found that the amount of time the humans spent doing nothing — while waiting for the robot to complete a stage of the task, for example — decreased by 41 percent. What's more, when the pair studied the robots themselves, they found that the learning algorithms recorded a much lower level of uncertainty about what their human teammate was likely to do next — a measure known as the entropy level — if they had been through cross-training," according to her Feb. 11 report. "Finally, when responding to a questionnaire after the experiment, human participants in cross-training were far more likely to say the robot had carried out the task according to their preferences than those in the reward-only group, and reported greater levels of trust in their robotic teammate."
"This is the first evidence that human-robot teamwork is improved when a human and robot train together by switching roles, in a manner similar to effective human team training practices," Nikolaidis said.