检索结果-内蒙古大学图书馆

Reward Engineering for Object Pick and Place Training

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Nagpal, Raghav Krishnan, Achyuthan Unni Yu, Hanshen Robotics Engineering Program Worcester Polytechnic Institute WorcesterMA01609 United States Mechanical Engineering Department Worcester Polytechnic Institute WorcesterMA01609 United States

—Robotic grasping is a crucial area of research as it can result in the acceleration of the automation of several Industries utilizing robots ranging from manufacturing to healthcare. Reinforcement learning is the field of study where an agent learns a policy to execute an action by exploring and exploiting rewards from an environment. Reinforcement learning can thus be used by the agent to learn how to execute a certain task, in our case grasping an object. We have used the Pick and Place environment provided by OpenAI’s Gym to engineer rewards. Hindsight Experience Replay (HER) has shown promising results with problems having a sparse reward. In the default configuration of the OpenAI baseline and environment the reward function is calculated using the distance between the target location and the robot end-effector. By weighting the cost based on the distance of the end-effector from the goal in the x,y and z-axes we were able to almost halve the learning time compared to the baselines provided by OpenAI, an intuitive strategy that further reduced learning time. In this project, we were also able to introduce certain user desired trajectories in the learnt policies (city-block / Manhattan trajectories). This helps us understand that by engineering the rewards we can tune the agent to learn policies in a certain way even if it might not be the most optimal but is the desired manner. Copyright © 2020, The Authors. All rights reserved.

关键词： End effectors

Time-to-Line Crossing Enhanced End-to-End Autonomous Driving Framework

学校读者我要写书评

暂无评论

Time-to-Line Crossing Enhanced End-to-End Autonomous Driving...

International Conference on Intelligent Transportation

作者： Chanyoung Jung Hyunki Seong David Hyunchul Shim School of Electrical Engineering Korea Advanced Institute of Science and Technology Daejeon South Korea KAIST Robotics Program Korea Advanced Institute of Science and Technology Daejeon South Korea

ISBN: (数字)9781728141497

ISBN: (纸本)9781728141503

End-to-end autonomous driving approach, which directly maps raw input images to vehicle control commands using a deep neural network, is gaining considerable attention from both academia and industry. Researchers have conducted studies on this subject over the past few years. However, they have focused on designing network architecture, and evaluated performance only with root mean square error (RMSE), which did not account for the temporal dynamics of autonomous driving. In this paper, we propose a time-to-line crossing (TLC) enhanced end-to-end driving framework. The proposed framework is original to the industry in three ways. First, for the fine-labeled training dataset for end-to-end autonomous driving, the TLC based label correction algorithm is applied to reduce the inaccuracies of driver action, which is used as a ground truth. Second, we designed a novel deep neural network model based on bi-directional convolutional long short-term memory (bi-CLSTM) which can sufficiently encode the spatial and temporal features in the input image sequence. Third, in addition to the RMSE evaluation metric, we validated the performance of the end-to-end driving model using TLC, the advanced driving support system (ADAS), and a driver performance indicator. We integrated the proposed framework with existing end-to-end driving models on a full-scale autonomous vehicle in the experimental portion of our study. The results show that the proposed framework is valid and that our network model outperforms the existing models in terms of both RMSE and TLC.

关键词： Feature extraction Autonomous vehicles Training Vehicles Network architecture Data mining Wheels

Adaptive Traffic Signal Control for Developing Countries Using Fused Parameters Derived from Crowd-Source Data

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Mishra, Sumit Singh, Vishal Gupta, Ankit Bhattacharya, Devanjan Mudgal, Abhisek The Robotics Program Korea Advanced Institute of Science and Technology Daejeon Korea Republic of Member of Technical Staff VMware Inc Palo AltoCA United States Department of Civil Engineering Indian Institute of Technology Banaras Hindu University Varanasi India Marie Sklodowska-Curie Actions TRAIN@ED School of Law School of Informatics University of Edinburgh United Kingdom Universidade Nova de Lisboa Campus de Campolide Lisboa1070-312 Portugal

Advancement of mobile technologies has enabled economical collection, storage, processing, and sharing of traffic data. These data are made accessible to intended users through various application program interfaces (API) and can be used to recognize and mitigate congestion in real time. In this paper, quantitative (time of arrival) and qualitative (color-coded congestion levels) data were acquired from the Google traffic APIs. New parameters that reflect heterogeneous traffic conditions were defined and utilized for real-time control of traffic signals while maintaining the green-to-red time ratio. The proposed method utilizes a congestion-avoiding principle commonly used in computer networking. Adaptive congestion levels were observed on three different intersections of Delhi (India), in peak hours. It showed good variation, hence sensitive for the control algorithm to act efficiently. Also, simulation study establishes that proposed control algorithm decreases waiting time and congestion. The proposed method provides an inexpensive alternative for traffic sensing and tracking technologies. © 2022, CC BY.

关键词： Crowdsourcing

Generating Localized Audible Zones Using a Single-Channel Parametric Loudspeaker

学校读者我要写书评

暂无评论

arXiv 2025年

作者： Zhuang, Tao Li, Shaozhe Niu, Feng Zhong, Jia-Xin Lu, Jing Key Laboratory of Modern Acoustics Nanjing University Nanjing210093 China NJU-Horizon Intelligent Audio Lab Horizon Robotics Beijing100094 China Division of Mechanics and Acoustics National Institute of Metrology Beijing100029 China Graduate Program in Acoustics The Pennsylvania State University University ParkPA16802 United States

Advanced sound zone control (SZC) techniques typically rely on massive multi-channel loudspeaker arrays to create high-contrast personal sound zones, making single-loudspeaker SZC seem impossible. In this Letter, we challenge this paradigm by introducing the multi-carrier parametric loudspeaker (MCPL), which enables SZC using only a single loudspeaker. In our approach, distinct audio signals are modulated onto separate ultrasonic carrier waves at different frequencies and combined into a single composite signal. This signal is emitted by a single-channel ultrasonic transducer, and through nonlinear demodulation in air, the audio signals interact to virtually form multi-channel outputs. This novel capability allows the application of existing SZC algorithms originally designed for multi-channel loudspeaker arrays. Simulations validate the effectiveness of our proposed single-channel MCPL, demonstrating its potential as a promising alternative to traditional multi-loudspeaker systems for achieving high-contrast SZC. Our work opens new avenues for simplifying SZC systems without compromising performance. © 2025, CC BY.

关键词： Array processing

Compositional planning in Markov decision processes: Temporal abstraction meets generalized logic composition

学校读者我要写书评

暂无评论

Compositional planning in Markov decision processes: Tempora...

American Control Conference

作者： Xuan Liu Jie Fu Robotics Engineering Program Worcester Polytechnic Institute Worcester MA USA

ISBN: (纸本)9781538679012;9781538679265

In hierarchical planning for Markov decision processes (MDPs), temporal abstraction allows planning with macro-actions that take place at different time scale in form of sequential composition. In this paper, we propose a novel approach to compositional reasoning and hierarchical planning for MDPs under co-safe temporal logic constraints. In addition to sequential composition, we introduce a composition of policies based on generalized logic composition: Given sub-policies for sub-tasks and a new task expressed as logic compositions of subtasks, a semi-optimal policy, which is optimal in planning with only sub-policies, can be obtained by simply composing sub-polices. Thus, a synthesis algorithm is developed to compute optimal policies efficiently by planning with primitive actions, policies for sub-tasks, and the compositions of sub-policies, for maximizing the probability of satisfying constraints specified in the fragment of co-safe temporal logic. We demonstrate the correctness and efficiency of the proposed method in stochastic planning examples with a single agent and multiple task specifications.

关键词： Markov chain time scales Planning Formal logic Policies Abstraction Temporal logic accuracy class

Socially acceptable route planning and trajectory behavior analysis of personal mobility device for mobility management with improved sensing

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Mishra, Sumit Rajendran, Praveen Kumar Har, Dongsoo The Robotics Program Department of Electrical Engineering Korea Advanced Institute of Science and Technology Daejeon Korea Republic of Division of Future Vehicle Department of Electrical Engineering Korea Advanced Institute of Science and Technology Daejeon Korea Republic of The CCS Graduate School of Green Transportation Korea Advanced Institute of Science and Technology Daejeon Korea Republic of

In urban cities, with increasing acceptability of shared spaces used by pedestrians and personal mobility devices (PMDs), there is need for pragmatic socially acceptable path planning and navigation management policies. Hence, we propose a socially acceptable global route planner and assess the legibility of the resulting global route. Our approach proposed for choosing global route avoids streets penetrating shared spaces and main routes with high probability of dense usage. The experimental study shows that socially acceptable routes can be effectively found with an average of 10 % increment of route length with optimal hyperparameters. This helps PMDs to reach the goal while taking a socially acceptable and safe route with minimal interaction of different PMDs and pedestrians. When PMDs interact with pedestrians and other types of PMDs in shared spaces, micro-mobility simulations are of prime usage for acceptable and safe navigation policy. Social force models being state of the art for pedestrian simulation are calibrated for capturing random movements of pedestrian behavior. Social force model with calibration can imitate the required behavior of PMDs in a pedestrian mix navigation scheme. Based on calibrated models, simulations on shared space links and gate structures are performed to assist policies related to deciding waiting and stopping time. Also, based on simulated PMDs interaction with pedestrians, location data with finer resolution can be obtained if the resolution of GPS sensor is 0.2 m or less. This will help in formalizing better modelling and hence better micro-mobility policies. Copyright © 2021, The Authors. All rights reserved.

关键词： Navigation

Topological Approximate Dynamic programming under Temporal Logic Constraints

学校读者我要写书评

暂无评论

Topological Approximate Dynamic Programming under Temporal L...

IEEE Annual Conference on Decision and Control

作者： Lening Li Jie Fu Robotics Engineering Program Worcester Polytechnic Institute Worcester MA USA

ISBN: (数字)9781728113982

ISBN: (纸本)9781728113999

In this paper, we develop a model-free approximate dynamic programming method for stochastic systems modeled as Markov decision processes to maximize the probability of satisfying high-level system specifications expressed in a subclass of temporal logic formulas-syntactically co-safe linear temporal logic. Our proposed method includes two steps: First, we decompose the planning problem into a sequence of sub-problems based on the topological property of the task automaton which is translated from a temporal logic formula. Second, we extend a model-free approximate dynamic programming method to solve value functions, one for each state in the task automaton, in an order reverse to the causal dependency. Particularly, we show that the run-time of the proposed algorithm does not grow exponentially with the size of specifications. The correctness and efficiency of the algorithm are demonstrated using a robotic motion planning example.

关键词： Task analysis Planning Dynamic programming Markov processes Automata Approximation algorithms Function approximation

Secure-by-synthesis network with active deception and temporal logic specifications

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Fu, Jie Kulkarni, Abhishek N. Luo, Huan Leslie, Nandi O. Kamhoua, Charles A. Dept. of Electrical and Computer Engineering Robotics Engineering Program Worcester Polytechnic Institute MA United States U.S. Army Research Laboratory MD United States

This paper is concerned with the synthesis of strategies in network systems with active cyber deception. Active deception in a network employs decoy systems and other defenses to conduct defensive planning against the intrusion of malicious attackers who have been confirmed by sensing systems. In this setting, the defender's objective is to ensure the satisfaction of security properties specified in temporal logic formulas. We formulate the problem of deceptive planning with decoy systems and other defenses as a two-player games with asymmetrical information and Boolean payoffs in temporal logic. We use level-2 hypergame with temporal logic objectives to capture the incomplete/incorrect knowledge of the attacker about the network system as a payoff misperception. The true payoff function is private information of the defender. Then, we extend the solution concepts of ω-regular games to analyze the attacker's rational strategy given her incomplete information. By generalizing the solution of level-2 hypergame in the normal form to extensive form, we extend the solutions of games with safe temporal logic objectives to decide whether the defender can ensure security properties to be satisfied with probability one, given any possible strategy that is perceived to be rational by the attacker. Further, we use the solution of games with co-safe (reachability) temporal logic objectives to determine whether the defender can engage the attacker, by directing the attacker to a high-fidelity honeypot. The effectiveness of the proposed synthesis methods is illustrated with synthetic network systems with honeypots. Copyright © 2020, The Authors. All rights reserved.

关键词： Temporal logic

Multimaterial 3D Nanoprinting of a 2 Fr Soft Robotic Microcatheter for Transarterial Chemoembolization of Liver Cancer

学校读者我要写书评

暂无评论

Multimaterial 3D Nanoprinting of a 2 Fr Soft Robotic Microca...

IEEE International Conference on Soft robotics (RoboSoft)

作者： Bailey M. Felix Jordi T. Andreou Sarah McHugh Jack E. McCann Olivia M. Young Molly A. Carton Dheeraj Gandhi Miroslaw Janowski Mark Fuge Axel Kreiger Clifford R. Weiss Christopher R. Bailey Ryan D. Sochol Fischell Department of Bioengineering University of Maryland College Park MD USA Department of Mechanical Engineering University of Maryland College Park MD USA Department of Diagnostic Radiology and Nuclear Medicine Program in Image Guided Neurointerventions University of Maryland School of Medicine Baltimore MD USA Department of Mechanical Engineering ETH Zurich Zurich Switzerland Department of Mechanical Engineering Johns Hopkins University Baltimore MD USA The Russell H. Morgan Department of Radiology and Radiological Science Division of Vascular and Interventional Radiology Johns Hopkins University School of Medicine Baltimore MD USA Maryland Robotics Center University of Maryland College Park MD USA Robert E. Fischell Institute for Biomedical Devices University of Maryland College Park MD USA

ISBN: (数字)9798331520205

ISBN: (纸本)9798331520212

Transarterial chemoembolization (TACE)—i.e., the delivery of chemotherapeutics directly into the vasculature of liver tumors—necessitates the use of guidewire-microcatheter systems to navigate tortuous vascular networks. These guide-wires and microcatheters typically lack effective steering controls, making successful navigation through geometrically complex anatomy challenging. Recent advancements in the area of soft microrobotics could offer a pathway to remotely steerable microcatheters at size scales relevant to TACE procedures; however, the difficulties associated with fabricating such systems have represented a critical hurdle. To overcome this barrier, here we present a multimaterial additive nanomanufacturing— or "three-dimensional (3D) nanoprinting"—strategy to achieve steerable soft robotic microcatheters that not only facilitate on-demand regulation of catheter tip deflection, but also comprise 2 French (Fr) outer dimensions (i.e., ⌀ = 666 μm) that are suitable for clinical chemoembolization of liver cancers. Specifically, we use "Two-Photon Direct Laser Writing (DLW)" to 3D nanoprint 1.5 mm-tall microcatheters capable of unidirectional tip bending of approximately 140° as well as mediating delivery of a fluidic payload. Experimental results for navigating the soft robotic microcatheter through a vascular phantom to deliver fluid payloads to target sites suggest the presented strategy holds promise for TACE as well as additional endovascular interventions and minimally invasive surgeries.

关键词： Liver cancer Actuators Navigation Deformation Phantoms Liver Soft robotics Bending Three-dimensional printing Payloads