Conformalized Teleoperation:

Confidently Mapping Human Inputs to High-Dimensional Robot Actions

Carnegie Mellon Unversity
Published at RSS 2024

Abstract

Assistive robotic arms often have more degrees-of-freedom than a human teleoperator can control with a low-dimensional input, like a joystick. To overcome this challenge, existing approaches use data-driven methods to learn a mapping from low-dimensional human inputs to high-dimensional robot actions. However, determining if such a black-box mapping can confidently infer a user's intended high-dimensional action from low-dimensional inputs remains an open problem. Our key idea is to adapt the assistive map at training time to additionally estimate high-dimensional action quantiles, and then calibrate these quantiles via rigorous uncertainty quantification methods. Specifically, we leverage adaptive conformal prediction which adjusts the intervals over time, reducing the uncertainty bounds when the mapping is performant and increasing the bounds when the mapping consistently mis-predicts. Furthermore, we propose an uncertainty-interval-based mechanism for detecting high-uncertainty user inputs and robot states. We evaluate the efficacy of our proposed approach in a 2D assistive navigation task and two 7DOF Kinova Jaco tasks involving assistive cup grasping and goal reaching. Our findings demonstrate that conformalized assistive teleoperation manages to detect (but not differentiate between) high uncertainty induced by diverse preferences and induced by low-precision trajectories in the mapping's training dataset. On the whole, we see this work as a key step towards enabling robots to quantify their own uncertainty and proactively seek intervention when needed.


Calibrating Uncertainty to Target User

During training, we modify the teleoperation controller to regress both the high-dimensional action corresponding with the low-dimensional human input, but also the empirical quantiles. (right) When deployed around a new user, we can calibrate the model to the user’s new dataset distribution. Adaptive Conformal Quantile Regression enables us to enlarge or shrink the predicted quantiles to get coverage of the user’s desired high-dimensional action.


Conformalized Teleoperation

We leverage conformal methods to quantify if the robot’s learned controller can reliably lift the human’s low-DoF input (joystick) to their desired high-DoF action (7 joint velocities). For any joystick input at the current state, the robot can assess its uncertainty in remapping that input (dot size in the expanded view is proportional to uncertainty at that coordinate). Arrows emphasize directional joystick input. (left, top) If the human pushes up or to the left on the joystick, the robot has low uncertainty, because it knows with high probability the person wants to go forward towards the object. (left, bottom) If the human pushes backwards on the joystick, the robot predicts a large pivot backwards, but is rightfully uncertain this is what the human intended.

Video Presentation

BibTeX



        @article{zhao2024conformalized,
          title={Conformalized Teleoperation: Confidently Mapping Human Inputs to High-Dimensional Robot Actions},
          author={Zhao, Michelle and Simmons, Reid and Admoni, Henny and Bajcsy, Andrea},
          journal={Robotics: Systems and Science},
          year={2024}
        }