Reviewerly/exHarmony huggingface dataset:
DynGMP: Graph Neural Network-Based Motion Planning in Unpredictable Dynamic Environments

Neural networks have already demonstrated attractive performance for solving motion planning problems, especially in static and predictable environments. However, efficient neural planners that can adapt to unpredictable dynamic environments, a highly demanded scenario in many practical applications, are still under-explored. To fill this research gap and enrich the existing motion planning approaches, in this pa-per, we propose DynGMP, a graph neural network (GNN)-based planner that provides high-performance planning solutions in unpredictable dynamic environments. By fully leveraging the prior exploration experience and minimizing the replanning cost incurred by environmental change, DynGMP achieves high planning performance and efficiency simultaneously. Empirical evaluations across different environments show that DynGMP can achieve close to 100% success rate with fast planning speed and short path cost. Compared with existing non-learning and learning-based counterparts, DynGMP shows very significant planning performance improvement, e.g., at least 2.7×, 2.2×, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2.4\times$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2\times$</tex> faster planning speed with low path distance in four environments, respectively.
RMBench: Benchmarking Deep Reinforcement Learning for Robotic Manipulator Control

Reinforcement learning is used to tackle complex tasks with high-dimensional sensory inputs. Over the past decade, a wide range of reinforcement learning algorithms have been developed, with recent progress benefiting from deep learning for raw sensory signal representation. This raises a natural question: how well do these algorithms perform across different robotic manipulation tasks? To objectively compare algorithms, benchmarks use performance metrics. Benchmarks use objective performance metrics to offer a scientific way to compare algorithms. In this paper, we introduce RMBench, the first benchmark for robotic manipulations with high-dimensional continuous action and state spaces. We implement and evaluate reinforcement learning algorithms that take observed pixels as inputs and report their average performance and learning curves to demonstrate their performance and training stability. Our study concludes that none of the evaluated algorithms can handle all tasks well, with soft Actor-Critic outperforming most algorithms in terms of average reward and stability, and an algorithm combined with data augmentation potentially facilitating learning policies. Our code is publicly available at https://github.com/xiangyanfei212/RMBench-2022.git, including all benchmark tasks and studied algorithms.
Track, Stop, and Eliminate: an Algorithm to Solve Stochastic Orienteering Problems Using MCTS

We present a novel algorithm to solve the stochastic orienteering problem with chance constraints that combines Monte Carlo Tree Search (MCTS) with a best arm identification (BAI) algorithm. This method extends our recently proposed solution that builds a search planning tree considering both an objective function to maximize, as well as a chance constraint on the failure probability, i.e., the probability of violating the assigned budget constraint. By combining these two approaches, we obtain a new planner that tunes the amount of tree search at run time. Extensive simulation results on our benchmark problems show that the new approach is significantly faster than the previous one, while incurring in just marginal decrements in terms of performance.
Improving the Performance of Backward Chained Behavior Trees that use Reinforcement Learning

In this paper we show how to improve the performance of backward chained behavior trees (BTs) that include policies trained with reinforcement learning (RL). BTs represent a hierarchical and modular way of combining control policies into higher level control policies. Backward chaining is a design principle for the construction of BTs that combines reactivity with goal directed actions in a structured way. The backward chained structure has also enabled convergence proofs for BTs, identifying a set of local conditions to be satisfied for the convergence of all trajectories to a set of desired goal states. The key idea of this paper is to improve performance of backward chained BTs by using the conditions identified in a theoretical convergence proof to configure the RL problems for individual controllers. Specifically, previous analysis identified so-called active constraint conditions (ACCs), that should not be violated in order to avoid having to return to work on previously achieved subgoals. We propose a way to set up the RL problems, such that they do not only achieve each immediate subgoal, but also avoid violating the identified ACCs. The resulting performance improvement depends on how often ACC violations occurred before the change, and how much effort, in terms of execution time, was needed to re-achieve them. The proposed approach is illustrated in a dynamic simulation environment.
Real-Time Trajectory-Based Social Group Detection

Social group detection is a crucial aspect of various robotic applications, including robot navigation and human-robot interactions. To date, a range of model-based techniques have been employed to address this challenge, such as the F-formation and trajectory similarity frameworks. However, these approaches often fail to provide reliable results in crowded and dynamic scenarios. Recent advancements in this area have mainly focused on learning-based methods, such as deep neural networks that use visual content or human pose. Although visual content based methods have demonstrated promising performance on large-scale datasets, their computational complexity poses a significant barrier to their practical use in real-time applications. To address these issues, we propose a simple and efficient framework for social group detection. Our approach explores the impact of motion trajectory on social grouping and utilizes a novel, reliable, and fast data-driven method. We formulate the individuals in a scene as a graph, where the nodes are represented by LSTM-encoded trajectories and the edges are defined by the distances between each pair of tracks. Our framework employs a modified graph transformer module and graph clustering losses to detect social groups. Our experiments on the popular JRDB-Act dataset reveal noticeable improvements in performance, with relative improvements ranging from 2% to 11%. Furthermore, our framework is significantly faster, with up to 12x faster inference times compared to state-of-the-art methods under the same computation resources. These results demonstrate that our proposed method is suitable for real-time robotic applications. .
Augmented Reality Navigation in Robot-Assisted Surgery with a Teleoperated Robotic Endoscope

Augmented reality (AR) is considered one of the most promising solutions for safer procedures in several surgical specialities. Fusing patient-specific pre-operative information, typically 3D models extracted from CT scans or MRI, with real-time surgical images allows the surgeon to have detailed information on the anatomical structure of the surgical target intra-operatively. The coupling of AR and Robotics represents the next step towards introducing awareness into the surgical room, thus enhancing the surgeon's perceptual, cognitive and manipulative capabilities. This paper presents a novel integrated system for real-time AR navigation in robotic minimally invasive surgery (RMIS), composed of a robotic endoscopic camera, a robotic teleoperation implementing a software-based Remote Center of Motion (RCM), and an AR navigation software based on an initial manual registration of virtual 3D models with the real anatomy. The integrated system, as well as the individual modules, were evaluated in simulated surgical-like setups for accuracy and repeatability. The proposed system can perform high-precision tasks (position accuracy around <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1 mm$</tex> and AR error lower than 7%), showing potential for application in different surgical procedures and setting the basis for autonomous robotic surgery operations.
Decentralized Multi-Agent Reinforcement Learning with Global State Prediction

Deep reinforcement learning (DRL) has seen re-markable success in the control of single robots. However, applying DRL to robot swarms presents significant challenges. A critical challenge is non-stationarity, which occurs when two or more robots update individual or shared policies concurrently, thereby engaging in an interdependent training process with no guarantees of convergence. Circumventing non-stationarity typically involves training the robots with global information about other agents' states and/or actions. In contrast, in this paper we explore how to remove the need for global information. We pose our problem as a Partially Observable Markov Decision Process, due to the absence of global knowledge on other agents. Using collective transport as a testbed scenario, we study two approaches to multi-agent training. In the first, the robots exchange no messages, and are trained to rely on implicit communication through push-and-pull on the object to transport. In the second approach, we introduce Global State Prediction (GSP), a network trained to form a belief over the swarm as a whole and predict its future states. We provide a comprehensive study over four well-known deep reinforcement learning algorithms in environments with obstacles, measuring performance as the successful transport of the object to a goal location within a desired time-frame. Through an ablation study, we show that including GSP boosts performance and increases robustness when compared with methods that use global knowledge.
Robust Unmanned Surface Vehicle Navigation with Distributional Reinforcement Learning

Autonomous navigation of Unmanned Surface Vehicles (USV) in marine environments with current flows is challenging, and few prior works have addressed the sensor-based navigation problem in such environments under no prior knowledge of the current flow and obstacles. We propose a Distributional Reinforcement Learning (RL) based local path planner that learns return distributions which capture the uncertainty of action outcomes, and an adaptive algorithm that automatically tunes the level of sensitivity to the risk in the environment. The proposed planner achieves a more stable learning performance and converges to safer policies than a traditional RL based planner. Computational experiments demonstrate that comparing to a traditional RL based planner and classical local planning methods such as Artificial Potential Fields and the Bug Algorithm, the proposed planner is robust against environmental flows, and is able to plan trajectories that are superior in safety, time and energy consumption.
RREx-BoT: Remote Referring Expressions with a Bag of Tricks

Household robots operate in the same space for years. Such robots incrementally build dynamic maps that can be used for tasks requiring remote object localization. However, benchmarks in robot learning often test generalization through inference on tasks in unobserved environments. In an observed environment, locating an object is reduced to choosing from among all object proposals in the environment, which may number in the 100,000s. Armed with this intuition, using only a generic vision-language scoring model with minor modifications for 3d encoding and operating in an embodied environment, we demonstrate an absolute performance gain of 9.84% on remote object grounding above state of the art models for REVERIE and of 5.04% on FAO. When allowed to pre-explore an environment, we also exceed the previous state of the art pre-exploration method on REVERIE. Additionally, we demonstrate our model on a real-world TurtleBot platform, highlighting the simplicity and usefulness of the approach. Our analysis outlines a “bag of tricks” essential for accomplishing this task, from utilizing 3d coordinates and context, to gener-alizing vision-language models to large 3d search spaces.
A New Method Combining Single-Point Push and Double-Point Complete Push for Partially Observable Scenarios

Pushing objects into a target configuration is an important skill for robots. When there are obstacles in the scenario, the movement range of the objects will be limited, and objects are easily lost due to obscured by obstacles, which complicates the pushing task. This paper proposes a push path planning algorithm SDP-RRT (Single and Double Push - Rapidly-exploring Random Tree) to combine single-point push and double-point complete push in a partially observable environment with obstacles. The single-double push combines the flexibility of a single-point push and the stability of a double-point complete push. To find the reliable pushing point and pushing direction of the double-point complete push, we improve the judgment conditions of the double-point complete push and estimate the object's center of mass based on the LSTM (Long Short-Term Memory) neural network. Finally, the success rate and push steps of single-double and single-point push are compared in both the simulation and the natural environments, and the feasibility of the SDP-RRT algorithm is verified.
ADMNet: Anti-Drone Real-Time Detection and Monitoring

We propose a lightweight, effective, and efficient anti-drone network, namely ADMNet, for visually detecting and monitoring unfriendly drones with a constrained view field, flying against a complex environment. We merge an SPP module to the first head of YOLOv4 to improve accuracy and perform network compression to reduce inference latency and model size. To compensate for the accuracy loss caused by condensation, we propose an SPPS module and a ResNeck module for the neck of the network and implement an effective attention module for the backbone. Eventually, we present an accurate and compact ADMNet with barely 3.9 MB, ensuring low computational cost and real-time detection. Our method achieves state-of-the-art performance on three challenging real-world datasets (Average Precision @0.5IoU): Det-Fly 96.2%, NPS-Drones 92.0%, and TIBNet 89.7%. The throughput is higher than the prior work, in addition to its superior performance. The comparative testing in real-world scenarios proves that our method exhibits strong reliability and generalization ability. Deploying the network on drone onboard edge-computing devices enables real-time detection and monitoring of flying drones, highlighting the portability and viability of the ADMNet.
Neural Architecture Search for Unsupervised PET Image Denoising

Deep image prior (DIP) has been proven to be an effective method to improve the image quality of positron emission tomography (PET) images when large datasets are not available. However most DIP-type methods are based on 3D U-net, which may be not suitable for unsupervised PET image denoising. In this work, we developed a neural architecture search method to find a better neural architecture for unsupervised PET image denoising. The cell level architecture and the network level architecture are searched alternatively. In each searching step, we designed a super network as a full set of all possible networks. Then the high-count PET images were used to update architecture and the low-count PET images were used to update weights. The performance of the searched architecture was evaluated through phantom study. The results showed that the searched neural architecture can better preserve image details while maintaining a lower noise level.
TemporalStereo: Efficient Spatial-Temporal Stereo Matching Network

We present TemporalStereo, a coarse-to-fine stereo matching network that is highly efficient, and able to effectively exploit the past geometry and context information to boost matching accuracy. Our network leverages sparse cost volume and proves to be effective when a single stereo pair is given. However, its peculiar ability to use spatio-temporal information across stereo sequences allows TemporalStereo to alleviate problems such as occlusions and reflective regions while enjoying high efficiency also in this latter case. Notably, our model - trained once with stereo videos - can run in both single-pair and temporal modes seamlessly. Experiments show that our network relying on camera motion is robust even to dynamic objects when running on videos. We validate TemporalStereo through extensive experiments on synthetic (SceneFlow, TartanAir) and real (KITTI 2012, KITTI 2015) datasets. Our model achieves state-of-the-art performance on any of these datasets.
Dynamic Decision Frequency with Continuous Options

In classic reinforcement learning algorithms, agents make decisions at discrete and fixed time intervals. The duration between decisions becomes a crucial hyperparameter, as setting it too short may increase the problem's difficulty by requiring the agent to make numerous decisions to achieve its goal while setting it too long can result in the agent losing control over the system. However, physical systems do not necessarily require a constant control frequency, and for learning agents, it is often preferable to operate with a low frequency when possible and a high frequency when necessary. We propose a framework called Continuous-Time Continuous-Options (CTCO), where the agent chooses options as sub-policies of variable durations. These options are time-continuous and can interact with the system at any desired frequency providing a smooth change of actions. We demonstrate the effectiveness of CTCO by comparing its performance to classical RL and temporal-abstraction RL methods on simulated continuous control tasks with various action-cycle times. We show that our algorithm's performance is not affected by the choice of environment interaction frequency. Furthermore, we demonstrate the efficacy of CTCO in facilitating exploration in a real-world visual reaching task for a 7 DOF robotic arm with sparse rewards.
Dynamic Multi-Query Motion Planning with Differential Constraints and Moving Goals

Planning robot motions in complex environments is a fundamental research challenge and central to the autonomy, efficiency, and ultimately adoption of robots. While often the environment is assumed to be static, real-world settings, such as assembly lines, contain complex shaped, moving obstacles and changing target states. Therein robots must perform safe and efficient motions to achieve their tasks. In repetitive environments and multi-goal settings, reusable roadmaps can substantially reduce the overall query time. Most dynamic roadmap-based planners operate in state-time-space, which is computationally demanding. Interval-based methods store availabilities as node attributes and thereby circumvent the dimensionality increase. However, current approaches do not consider higher-order constraints, which can ultimately lead to collisions during execution. Furthermore, current approaches must replan when the goal changes. To this end, we propose a novel roadmap-based planner for systems with third-order differential constraints operating in dynamic environments with moving goals. We construct a roadmap with availabilities as node attributes. During the query phase, we use a Double-Integrator Minimum Time (DIMT) solver to recursively build feasible trajectories and accurately estimate arrival times. An exit node set in combination with a moving goal heuristic is used to efficiently find the fastest path through the roadmap to the moving goal. We evaluate our method with a simulated UAV operating in dynamic 2D environments and show that it also transfers to a 6-DoF manipulator. We show higher success rates than other state-of-the-art methods both in collision avoidance and reaching a moving goal.
Consecutive Inertia Drift of Autonomous RC Car via Primitive-Based Planning and Data-Driven Control

Inertia drift is an aggressive transitional driving maneuver, which is challenging due to the high nonlinearity of the system and the stringent requirement on control and planning performance. This paper presents a solution for the consecutive inertia drift of an autonomous RC car based on primitive-based planning and data-driven control. The planner generates complex paths via the concatenation of path segments called primitives, and the controller eases the burden on feedback by interpolating between multiple real trajectories with different initial conditions into one near-feasible reference trajectory. The proposed strategy is capable of drifting through various paths containing consecutive turns, which is validated in both simulation and reality.
TauPETGen: Text-Conditional Tau PET Image Synthesis Based on Latent Diffusion Models

In this work, we developed a novel text-guided image synthesis technique that could generate realistic tau PET images from textual descriptions and the subject's MR image. The generated tau PET images have the potential to be used in examining relations between different measures and also increasing the public availability of tau PET datasets. The method was based on latent diffusion models. Both textual descriptions and the subject's MR prior image were utilized as conditions during image generation. The subject's MR image can provide anatomical details, while the text descriptions, such as gender, scan time, cognitive test scores, and amyloid status, can provide further guidance regarding where the tau neurofibrillary tangles might be deposited. Preliminary experimental results based on clinical [18F]MK-6240 datasets demonstrate the feasibility of the proposed method in generating realistic tau PET images at different clinical stages.
Depth Self-Supervision for Single Image Novel View Synthesis

In this paper, we tackle the problem of generating a novel image from an arbitrary viewpoint given a single frame as input. While existing methods operating in this setup aim at predicting the target view depth map to guide the synthesis, without explicit supervision over such a task, we jointly optimize our framework for both novel view synthesis and depth estimation to unleash the synergy between the two at its best. Specifically, a shared depth decoder is trained in a self-supervised manner to predict depth maps that are consistent across the source and target views. Our results demonstrate the effectiveness of our approach in addressing the challenges of both tasks allowing for higher-quality generated images, as well as more accurate depth for the target viewpoint.
GOATS: Goal Sampling Adaptation for Scooping with Curriculum Reinforcement Learning

In this work, we first formulate the problem of robotic water scooping using goal-conditioned reinforcement learning. This task is particularly challenging due to the complex dynamics of fluid and the need to achieve multi-modal goals. The policy is required to successfully reach both position goals and water amount goals, which leads to a large convoluted goal state space. To overcome these challenges, we introduce Goal Sampling Adaptation for Scooping (GOATS), a curriculum reinforcement learning method that can learn an effective and generalizable policy for robot scooping tasks. Specifically, we use a goal-factorized reward formulation and interpolate position goal distributions and amount goal distributions to create curriculum throughout the learning process. As a result, our proposed method can outperform the baselines in simulation and achieves 5.46% and 8.71% amount errors on bowl scooping and bucket scooping tasks, respectively, under 1000 variations of initial water states in the tank and a large goal state space. Besides being effective in simulation environments, our method can efficiently adapt to noisy real-robot water-scooping scenarios with diverse physical configurations and unseen settings, demonstrating superior efficacy and generalizability. The videos of this work are available on our project page: https://sites.google.com/view/goatscooping.