Author name cluster

Henny Admoni

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

15 papers

2 author rows

ICLR Conference 2025 Conference Paper

Conformalized Interactive Imitation Learning: Handling Expert Shift and Intermittent Feedback

Michelle Zhao
Henny Admoni
Reid G. Simmons
Aaditya Ramdas
Andrea Bajcsy

In interactive imitation learning (IL), uncertainty quantification offers a way for the learner (i.e. robot) to contend with distribution shifts encountered during deployment by actively seeking additional feedback from an expert (i.e. human) online. Prior works use mechanisms like ensemble disagreement or Monte Carlo dropout to quantify when black-box IL policies are uncertain; however, these approaches can lead to overconfident estimates when faced with deployment-time distribution shifts. Instead, we contend that we need uncertainty quantification algorithms that can leverage the expert human feedback received during deployment time to adapt the robot's uncertainty online. To tackle this, we draw upon online conformal prediction, a distribution-free method for constructing prediction intervals online given a stream of ground-truth labels. Human labels, however, are intermittent in the interactive IL setting. Thus, from the conformal prediction side, we introduce a novel uncertainty quantification algorithm called intermittent quantile tracking (IQT) that leverages a probabilistic model of intermittent labels, maintains asymptotic coverage guarantees, and empirically achieves desired coverage levels. From the interactive IL side, we develop ConformalDAgger, a new approach wherein the robot uses prediction intervals calibrated by IQT as a reliable measure of deployment-time uncertainty to actively query for more expert feedback. We compare ConformalDAgger to prior uncertainty-aware DAgger methods in scenarios where the distribution shift is (and isn't) present because of changes in the expert's policy. We find that in simulated and hardware deployments on a 7DOF robotic manipulator, ConformalDAgger detects high uncertainty when the expert shifts and increases the number of interventions compared to baselines, allowing the robot to more quickly learn the new behavior.

Details

AAMAS Conference 2024 Conference Paper

Bootstrapping Linear Models for Fast Online Adaptation in Human-Agent Collaboration

Benjamin A. Newman
Chris Paxton
Kris Kitani
Henny Admoni

Agents that assist people need to have well-initialized policies that can adapt quickly to align with their partners’ reward functions. Initializing policies to maximize performance with unknown partners can be achieved by bootstrapping nonlinear models using imitation learning over large, offline datasets. Such policies can require prohibitive computation to fine-tune in-situ and therefore may miss critical run-time information about a partner’s reward function as expressed through their immediate behavior. In contrast, online logistic regression using low-capacity models performs rapid inference and fine-tuning updates and thus can make effective use of immediate in-task behavior for reward function alignment. However, these low-capacity models cannot be bootstrapped as effectively by offline datasets and thus have poor initializations. We propose BLR-HAC, Bootstrapped Logistic Regression for Human Agent Collaboration, which bootstraps large nonlinear models to learn the parameters of a low-capacity model which then uses online logistic regression for updates during collaboration. We test BLR-HAC in a simulated surface rearrangement task and demonstrate that it achieves higher zero-shot accuracy than shallow methods and takes far less computation to adapt online while still achieving similar performance to fine-tuned, large nonlinear models. For code, please see our project page https: //sites. google. com/view/blr-hac

PDF

AAMAS Conference 2024 Conference Paper

Gaze Supervision for Mitigating Causal Confusion in Driving Agents

Abhijat Biswas
Badal Arun Pardhi
Caleb Chuck
Jarrett Holtz
Scott Niekum
Henny Admoni
Alessandro Allievi

Imitation Learning (IL) algorithms show promise in learning humanlevel driving behavior, but they often suffer from "causal confusion, " a phenomenon where the lack of explicit inference of the underlying causal structure can result in misattribution of the relative importance of scene elements, especially pronounced in complex scenarios like urban driving with abundant information per time step. Our key idea is that while driving, human drivers naturally exhibit an easily obtained, continuous signal that is highly correlated with causal elements of the state space: eye gaze. We collect human driver demonstrations in a CARLA-based VR driving simulator, allowing us to capture eye gaze in the same simulation environment commonly used in prior work. Further, we propose a method to use gaze-based supervision to mitigate causal confusion in driving IL agents — exploiting the relative importance of gazed-at and notgazed-at scene elements for driving decision-making. We present quantitative results demonstrating the promise of gaze-based supervision improving the driving performance of IL agents.

PDF

ICRA Conference 2024 Conference Paper

Multi-Agent Strategy Explanations for Human-Robot Collaboration

Ravi Pandya
Michelle Zhao
Changliu Liu
Reid G. Simmons
Henny Admoni

As robots are deployed in human spaces, it is important that they are able to coordinate their actions with the people around them. Part of such coordination involves ensuring that people have a good understanding of how a robot will act in the environment. This can be achieved through explanations of the robot’s policy. Much prior work in explainable AI and RL focuses on generating explanations for single-agent policies, but little has been explored in generating explanations for collaborative policies. In this work, we investigate how to generate multi-agent strategy explanations for human-robot collaboration. We formulate the problem using a generic multi-agent planner, show how to generate visual explanations through strategy-conditioned landmark states and generate textual explanations by giving the landmarks to an LLM. Through a user study, we find that when presented with explanations from our proposed framework, users are able to better explore the full space of strategies and collaborate more efficiently with new robot partners.

Details

IROS Conference 2024 Conference Paper

Understanding Robot Minds: Leveraging Machine Teaching for Transparent Human-Robot Collaboration Across Diverse Groups

Suresh Kumaar Jayaraman
Reid G. Simmons
Aaron Steinfeld
Henny Admoni

In this work, we aim to improve transparency and efficacy in human-robot collaboration by developing machine teaching algorithms suitable for groups with varied learning capabilities. While previous approaches focused on tailored approaches for teaching individuals, our method teaches teams with various compositions of diverse learners using team belief representations. We investigate various group teaching strategies, such as focusing on individual beliefs or the group’s collective beliefs, and assess their impact on learning robot policies for different team compositions. Our findings reveal that team belief strategies produce less variation in learning duration and better accommodate diverse teams compared to individual belief strategies, suggesting their suitability in mixed proficiency settings with limited resources. In contrast, individual belief strategies provide a more uniform knowledge level, particularly effective for homogeneously inexperienced groups. Our study indicates that the effectiveness of the teaching strategy is significantly influenced by team composition and learner proficiency, highlighting the importance of real-time assessment of learner proficiency and adapting teaching approaches based on learner proficiency for optimal teaching outcomes.

Details

IROS Conference 2022 Conference Paper

Coordination With Humans Via Strategy Matching

Michelle Zhao
Reid G. Simmons
Henny Admoni

Human and robot partners increasingly need to work together to perform tasks as a team. Robots designed for such collaboration must reason about how their task-completion strategies interplay with the behavior and skills of their human team members as they coordinate on achieving joint goals. Our goal in this work is to develop a computational framework for robot adaptation to human partners in human-robot team collaborations. We first present an algorithm for autonomously recognizing available task-completion strategies by observing human-human teams performing a collaborative task. By transforming team actions into low dimensional representations using hidden Markov models, we can identify strategies without prior knowledge. Robot policies are learned on each of the identified strategies to construct a Mixture-of-Experts model that adapts to the task strategies of unseen human partners. We evaluate our model on a collaborative cooking task using an Overcooked simulator. Results of an online user study with 125 participants demonstrate that our framework improves the task performance and collaborative fluency of human-agent teams, as compared to state of the art reinforcement learning methods.

Details

IROS Conference 2022 Conference Paper

Reasoning about Counterfactuals to Improve Human Inverse Reinforcement Learning

Michael S. Lee
Henny Admoni
Reid G. Simmons

To collaborate well with robots, we must be able to understand their decision making. Humans naturally infer other agents' beliefs and desires by reasoning about their observable behavior in a way that resembles inverse reinforcement learning (IRL). Thus, robots can convey their beliefs and desires by providing demonstrations that are informative for a human learner's IRL. An informative demonstration is one that differs strongly from the learner's expectations of what the robot will do given their current understanding of the robot's decision making. However, standard IRL does not model the learner's existing expectations, and thus cannot do this counterfactual reasoning. We propose to incorporate the learner's current understanding of the robot's decision making into our model of human IRL, so that a robot can select demonstrations that maximize the human's understanding. We also propose a novel measure for estimating the difficulty for a human to predict instances of a robot's behavior in unseen environments. A user study finds that our test difficulty measure correlates well with human performance and confidence. Interestingly, considering human beliefs and counterfactuals when selecting demonstrations decreases human performance on easy tests, but increases performance on difficult tests, providing insight on how to best utilize such models.

Details

IROS Conference 2021 Conference Paper

Inferring Goals with Gaze during Teleoperated Manipulation

Reuben M. Aronson
Nadia Almutlak
Henny Admoni

Assistive robot manipulators help people with upper motor impairments perform tasks by themselves. However, teleoperating a robot to perform complex tasks is difficult. Shared control algorithms make this easier: these algorithms predict the user’s goal, autonomously generate a plan to accomplish the goal, and fuse that plan with the user’s input. To accurately predict the user’s goal, these algorithms typically use the user’s input command (e. g. , joystick input) directly. We use another sensing modality: the user’s natural eye gaze behavior, which is highly task-relevant and informative early in the task. We develop an algorithm using hidden Markov models to infer goals from natural eye gaze behavior that appears while users are teleoperating a robot. We show that gaze-based predictions outperform goal prediction based on the control input and that our sequence model improves the prediction quality relative to gaze-based aggregate models.

Details

IJCAI Conference 2021 Conference Paper

Interaction Considerations in Learning from Humans

Pallavi Koppol
Henny Admoni
Reid Simmons

The ability to learn from large quantities of complex data has led to the development of intelligent agents such as self-driving cars and assistive devices. This data often comes from people via interactions such as labeling, providing rewards and punishments, and giving demonstrations or critiques. However, people's ability to provide high-quality data can be affected by human factors of an interaction, such as induced cognitive load and perceived usability. We show that these human factors differ significantly between interaction types. We first formalize interactions as a Markov Decision Process, and construct a taxonomy of these interactions to identify four archetypes: Showing, Categorizing, Sorting, and Evaluating. We then run a user study across two task domains. Our findings show that Evaluating interactions are more cognitively loading and less usable than the others, and Categorizing and Showing interactions are the least cognitively loading and most usable.

PDF Details DOI

ICRA Conference 2021 Conference Paper

Learning from Demonstration for Real-Time User Goal Prediction and Shared Assistive Control

Calvin Z. Qiao
Maram Sakr
Katharina Muelling
Henny Admoni

In shared autonomy, the user input is blended with the assistive motion to accomplish a task where the user goal is typically unknown to the robot. Transparency between the human and robot is essential for effective collaboration. Prior works have provided methods for the robot to infer the user goal; however, they are usually dependent on the distance between the robot and object, which may not be directly associated with the real-time user control intention and thus cause low control feelings. Here, we propose a real-time goal prediction method driven by assistive motion generated by learning from demonstration (LfD) allowing more reactive assistive behaviors. This LfD-generated assistive motion is blended with the user input based on goal predictions to achieve targeted tasks. The LfD policy was learned offline and used with different users. To evaluate our proposed method, we compared it with a state-of-the-art Partially Observable Markov Decision Process (POMDP) based method using a distance cost, and a direct control method (i. e. , joystick). A pilot study (N = 6) was conducted to control a 6-DoF Kinova Mico robotic arm to carry out three tasks: (1) reaching-and-grasping, (2) pouring, and (3) object-returning with the three control methods. We used both objective and subjective measures in the comparative study. Results show that our method has the shortest task completion time, the lowest amount of joystick control inputs among all three control methods, as well as a significantly lower angular difference between the user input and assistive motion compared to the POMDP-based method. Besides, it obtains the highest subjective score in the user preference and perceived speed ratings, and the second-highest in the control feeling and the robot did what I wanted ratings.

Details

IJCAI Conference 2021 Conference Paper

Understanding the Relationship between Interactions and Outcomes in Human-in-the-Loop Machine Learning

Yuchen Cui
Pallavi Koppol
Henny Admoni
Scott Niekum
Reid Simmons
Aaron Steinfeld
Tesca Fitzgerald

Human-in-the-loop Machine Learning (HIL-ML) is a widely adopted paradigm for instilling human knowledge in autonomous agents. Many design choices influence the efficiency and effectiveness of such interactive learning processes, particularly the interaction type through which the human teacher may provide feedback. While different interaction types (demonstrations, preferences, etc. ) have been proposed and evaluated in the HIL-ML literature, there has been little discussion of how these compare or how they should be selected to best address a particular learning problem. In this survey, we propose an organizing principle for HIL-ML that provides a way to analyze the effects of interaction types on human performance and training data. We also identify open problems in understanding the effects of interaction types.

PDF Details DOI

IROS Conference 2020 Conference Paper

Diminished Reality for Close Quarters Robotic Telemanipulation

Ada Virginia Taylor
Ayaka Matsumoto
Elizabeth J. Carter
Alexander Plopski
Henny Admoni

In robot telemanipulation tasks, the robot can sometimes occlude a target object from the user's view. We investigate the potential of diminished reality to address this problem. Our method uses an optical see-through head-mounted display to create a diminished reality illusion that the robot is transparent, allowing users to see occluded areas behind the robot. To investigate benefits and drawbacks of robot transparency, we conducted a user study that examined diminished reality in a simple telemanipulation task involving both occluded and unoccluded targets. We discovered that while these visualizations show promise for reducing user effort, there are drawbacks in terms of task efficiency and user preference. We identified several friction points in user experiences with diminished reality interfaces. Finally, we describe several design trade-offs among different visualization options.

Details

IROS Conference 2020 Conference Paper

Learning Vision-Based Physics Intuition Models for Non-Disruptive Object Extraction

Sarthak Ahuja
Henny Admoni
Aaron Steinfeld

Robots operating in human environments must be careful, when executing their manipulation skills, not to disturb nearby objects. This requires robots to reason about the effect of their manipulation choices by accounting for the support relationships among objects in the scene. Humans do this in part by visually assessing their surroundings and using physics intuition for how likely it is that a particular object can be safely manipulated (i. e. , cause no disruption in the rest of the scene). Existing work has shown that deep convolutional neural networks can learn intuitive physics over images generated in simulation and determine the stability of a scene in the real world. In this paper, we extend these physics intuition models to the task of assessing safe object extraction by conditioning the visual images on specific objects in the scene. Our results, in both simulation and real-world settings, show that with our proposed method, physics intuition models can be used to inform a robot of which objects can be safely extracted and from which direction to extract them.

Details

IROS Conference 2016 Conference Paper

Human-robot shared workspace collaboration via hindsight optimization

Stefania Pellegrinelli
Henny Admoni
Shervin Javdani
Siddhartha S. Srinivasa

Our human-robot collaboration research aims to improve the fluency and efficiency of interactions between humans and robots when executing a set of tasks in a shared workspace. During human-robot collaboration, a robot and a user must often complete a disjoint set of tasks that use an overlapping set of objects, without using the same object simultaneously. A key challenge is deciding what task the robot should perform next in order to facilitate fluent and efficient collaboration. Most prior work does so by first predicting the human's intended goal, and then selecting actions given that goal. However, it is often difficult, and sometimes impossible, to infer the human's exact goal in real time, and this serial predict-then-act method is not adaptive to changes in human goals. In this paper, we present a system for inferring a probability distribution over human goals, and producing assistance actions given that distribution in real time. The aim is to minimize the disruption caused by the nature of human-robot shared workspace. We extend recent work utilizing Partially Observable Markov Decision Processes (POMDPs) for shared autonomy in order to provide assistance without knowing the exact goal. We evaluate our system in a study with 28 participants, and show that our POMDP model outperforms state of the art predict-then-act models by producing fewer human-robot collisions and less human idling time.

Details

ICRA Conference 2016 Conference Paper

Modeling communicative behaviors for object references in human-robot interaction

Henny Admoni
Thomas Weng
Brian Scassellati

This paper presents a model that uses a robot's verbal and nonverbal behaviors to successfully communicate object references to a human partner. This model, which is informed by computer vision, human-robot interaction, and cognitive psychology, simulates how low-level and high-level features of the scene might draw a user's attention. It then selects the most appropriate robot behavior that maximizes the likelihood that a user will understand the correct object reference while minimizing the cost of the behavior. We present a general computational framework for this model, then describe a specific implementation in a human-robot collaboration. Finally, we analyze the model's performance in two human evaluations—one video-based (75 participants) and one in person (20 participants)—and demonstrate that the system predicts the correct behaviors to perform successful object references.

Details