Ko, Jonathan
An Adaptable, Safe, and Portable Robot-Assisted Feeding System
Gordon, Ethan Kroll, Jenamani, Rajat Kumar, Nanavati, Amal, Liu, Ziang, Bolotski, Haya, Karim, Raida, Stabile, Daniel, Kashyap, Atharva, Zhu, Bernie Hao, Dai, Xilai, Schrenk, Tyler, Ko, Jonathan, Faulkner, Taylor Kessler, Bhattacharjee, Tapomayukh, Srinivasa, Siddhartha
We demonstrate a robot-assisted feeding system that enables people with mobility impairments to feed themselves. Our system design embodies Safety, Portability, and User Control, with comprehensive full-stack safety checks, the ability to be mounted on and powered by any powered wheelchair, and a custom web-app allowing care-recipients to leverage their own assistive devices for robot control. For bite acquisition, we leverage multi-modal online learning to tractably adapt to unseen food types. For bite transfer, we leverage real-time mouth perception and interaction-aware control. Co-designed with community researchers, our system has been validated through multiple end-user studies.
The Revisiting Problem in Mobile Robot Map Building: A Hierarchical Bayesian Approach
Stewart, Benjamin, Ko, Jonathan, Fox, Dieter, Konolige, Kurt
We present an application of hierarchical Bayesian estimation to robot map building. The revisiting problem occurs when a robot has to decide whether it is seeing a previously-built portion of a map, or is exploring new territory. This is a difficult decision problem, requiring the probability of being outside of the current known map. To estimate this probability, we model the structure of a "typical" environment as a hidden Markov model that generates sequences of views observed by a robot navigating through the environment. A Dirichlet prior over structural models is learned from previously explored environments. Whenever a robot explores a new environment, the posterior over the model is estimated by Dirichlet hyperparameters. Our approach is implemented and tested in the context of multi-robot map merging, a particularly difficult instance of the revisiting problem. Experiments with robot data show that the technique yields strong improvements over alternative methods.