Yuzhu Sun, Mien Van, Stephen McIlvanna, Nguyen Minh Nhat, Kabirat Olayemi, Jack Close, Seán McLoone
{"title":"Digital Twin-Driven Reinforcement Learning for Obstacle Avoidance in Robot Manipulators: A Self-Improving Online Training Framework","authors":"Yuzhu Sun, Mien Van, Stephen McIlvanna, Nguyen Minh Nhat, Kabirat Olayemi, Jack Close, Seán McLoone","doi":"arxiv-2403.13090","DOIUrl":"https://doi.org/arxiv-2403.13090","url":null,"abstract":"The evolution and growing automation of collaborative robots introduce more\u0000complexity and unpredictability to systems, highlighting the crucial need for\u0000robot's adaptability and flexibility to address the increasing complexities of\u0000their environment. In typical industrial production scenarios, robots are often\u0000required to be re-programmed when facing a more demanding task or even a few\u0000changes in workspace conditions. To increase productivity, efficiency and\u0000reduce human effort in the design process, this paper explores the potential of\u0000using digital twin combined with Reinforcement Learning (RL) to enable robots\u0000to generate self-improving collision-free trajectories in real time. The\u0000digital twin, acting as a virtual counterpart of the physical system, serves as\u0000a 'forward run' for monitoring, controlling, and optimizing the physical system\u0000in a safe and cost-effective manner. The physical system sends data to\u0000synchronize the digital system through the video feeds from cameras, which\u0000allows the virtual robot to update its observation and policy based on real\u0000scenarios. The bidirectional communication between digital and physical systems\u0000provides a promising platform for hardware-in-the-loop RL training through\u0000trial and error until the robot successfully adapts to its new environment. The\u0000proposed online training framework is demonstrated on the Unfactory Xarm5\u0000collaborative robot, where the robot end-effector aims to reach the target\u0000position while avoiding obstacles. The experiment suggest that proposed\u0000framework is capable of performing policy online training, and that there\u0000remains significant room for improvement.","PeriodicalId":501062,"journal":{"name":"arXiv - CS - Systems and Control","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140196685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jelmer de Wolde, Luzia Knoedler, Gianluca Garofalo, Javier Alonso-Mora
{"title":"Current-Based Impedance Control for Interacting with Mobile Manipulators","authors":"Jelmer de Wolde, Luzia Knoedler, Gianluca Garofalo, Javier Alonso-Mora","doi":"arxiv-2403.13079","DOIUrl":"https://doi.org/arxiv-2403.13079","url":null,"abstract":"As robots shift from industrial to human-centered spaces, adopting mobile\u0000manipulators, which expand workspace capabilities, becomes crucial. In these\u0000settings, seamless interaction with humans necessitates compliant control. Two\u0000common methods for safe interaction, admittance, and impedance control, require\u0000force or torque sensors, often absent in lower-cost or lightweight robots. This\u0000paper presents an adaption of impedance control that can be used on\u0000current-controlled robots without the use of force or torque sensors and its\u0000application for compliant control of a mobile manipulator. A calibration method\u0000is designed that enables estimation of the actuators' current/torque ratios and\u0000frictions, used by the adapted impedance controller, and that can handle model\u0000errors. The calibration method and the performance of the designed controller\u0000are experimentally validated using the Kinova GEN3 Lite arm. Results show that\u0000the calibration method is consistent and that the designed controller for the\u0000arm is compliant while also being able to track targets with five-millimeter\u0000precision when no interaction is present. Additionally, this paper presents two\u0000operational modes for interacting with the mobile manipulator: one for guiding\u0000the robot around the workspace through interacting with the arm and another for\u0000executing a tracking task, both maintaining compliance to external forces.\u0000These operational modes were tested in real-world experiments, affirming their\u0000practical applicability and effectiveness.","PeriodicalId":501062,"journal":{"name":"arXiv - CS - Systems and Control","volume":"151 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140197026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Most Likely Sequence Generation for $n$-Grams, Transformers, HMMs, and Markov Chains, by Using Rollout Algorithms","authors":"Yuchao Li, Dimitri Bertsekas","doi":"arxiv-2403.15465","DOIUrl":"https://doi.org/arxiv-2403.15465","url":null,"abstract":"In this paper we consider a transformer with an $n$-gram structure, such as\u0000the one underlying ChatGPT. The transformer provides next word probabilities,\u0000which can be used to generate word sequences. We consider methods for computing\u0000word sequences that are highly likely, based on these probabilities. Computing\u0000the optimal (i.e., most likely) word sequence starting with a given initial\u0000state is an intractable problem, so we propose methods to compute highly likely\u0000sequences of $N$ words in time that is a low order polynomial in $N$ and in the\u0000vocabulary size of the $n$-gram. These methods are based on the rollout\u0000approach from approximate dynamic programming, a form of single policy\u0000iteration, which can improve the performance of any given heuristic policy. In\u0000our case we use a greedy heuristic that generates as next word one that has the\u0000highest probability. We show with analysis, examples, and computational\u0000experimentation that our methods are capable of generating highly likely\u0000sequences with a modest increase in computation over the greedy heuristic.\u0000While our analysis and experiments are focused on Markov chains of the type\u0000arising in transformer and ChatGPT-like models, our methods apply to general\u0000finite-state Markov chains, and related inference applications of Hidden Markov\u0000Models (HMM), where Viterbi decoding is used extensively.","PeriodicalId":501062,"journal":{"name":"arXiv - CS - Systems and Control","volume":"2016 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140297572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hybrid Unsupervised Learning Strategy for Monitoring Industrial Batch Processes","authors":"Christian W. Frey","doi":"arxiv-2403.13032","DOIUrl":"https://doi.org/arxiv-2403.13032","url":null,"abstract":"Industrial production processes, especially in the pharmaceutical industry,\u0000are complex systems that require continuous monitoring to ensure efficiency,\u0000product quality, and safety. This paper presents a hybrid unsupervised learning\u0000strategy (HULS) for monitoring complex industrial processes. Addressing the\u0000limitations of traditional Self-Organizing Maps (SOMs), especially in scenarios\u0000with unbalanced data sets and highly correlated process variables, HULS\u0000combines existing unsupervised learning techniques to address these challenges.\u0000To evaluate the performance of the HULS concept, comparative experiments are\u0000performed based on a laboratory batch","PeriodicalId":501062,"journal":{"name":"arXiv - CS - Systems and Control","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140196627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lasse Bienzeisler, Torben Lelke, Bernhard Friedrich
{"title":"Autonomous Underground Freight Transport Systems -- The Future of Urban Logistics?","authors":"Lasse Bienzeisler, Torben Lelke, Bernhard Friedrich","doi":"arxiv-2403.08841","DOIUrl":"https://doi.org/arxiv-2403.08841","url":null,"abstract":"We design a concept for an autonomous underground freight transport system\u0000for Hanover, Germany. To evaluate the resulting system changes in overall\u0000traffic flows from an environmental perspective, we carried out an agent-based\u0000traffic simulation with MATSim. Our simulations indicate comparatively low\u0000impacts on network-wide traffic volumes. Local CO2 emissions, on the other\u0000hand, could be reduced by up to 32 %. In total, the shuttle system can replace\u0000more than 18 % of the vehicles in use with conventional combustion engines.\u0000Thus, an autonomous underground freight transportation system can contribute to\u0000environmentally friendly and economical transportation of urban goods on the\u0000condition of cooperative use of the system.","PeriodicalId":501062,"journal":{"name":"arXiv - CS - Systems and Control","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140150490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Adaptive Gain Scheduling using Reinforcement Learning for Quadcopter Control","authors":"Mike Timmerman, Aryan Patel, Tim Reinhart","doi":"arxiv-2403.07216","DOIUrl":"https://doi.org/arxiv-2403.07216","url":null,"abstract":"The paper presents a technique using reinforcement learning (RL) to adapt the\u0000control gains of a quadcopter controller. Specifically, we employed Proximal\u0000Policy Optimization (PPO) to train a policy which adapts the gains of a\u0000cascaded feedback controller in-flight. The primary goal of this controller is\u0000to minimize tracking error while following a specified trajectory. The paper's\u0000key objective is to analyze the effectiveness of the adaptive gain policy and\u0000compare it to the performance of a static gain control algorithm, where the\u0000Integral Squared Error and Integral Time Squared Error are used as metrics. The\u0000results show that the adaptive gain scheme achieves over 40$%$ decrease in\u0000tracking error as compared to the static gain controller.","PeriodicalId":501062,"journal":{"name":"arXiv - CS - Systems and Control","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140114959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Characterizing Flow Complexity in Transportation Networks using Graph Homology","authors":"Shashank A Deshpande, Hamsa Balakrishnan","doi":"arxiv-2403.05749","DOIUrl":"https://doi.org/arxiv-2403.05749","url":null,"abstract":"Series-parallel network topologies generally exhibit simplified dynamical\u0000behavior and avoid high combinatorial complexity. A comprehensive analysis of\u0000how flow complexity emerges with a graph's deviation from series-parallel\u0000topology is therefore of fundamental interest. We introduce the notion of a\u0000robust $k$-path on a directed acycylic graph, with increasing values of the\u0000length $k$ reflecting increasing deviations. We propose a graph homology with\u0000robust $k$-paths as the bases of its chain spaces. In this framework, the\u0000topological simplicity of series-parallel graphs translates into a triviality\u0000of higher-order chain spaces. We discuss a correspondence between the space of\u0000order-three chains and sites within the network that are susceptible to the\u0000Braess paradox, a well-known phenomenon in transportation networks. In this\u0000manner, we illustrate the utility of the proposed graph homology in\u0000sytematically studying the complexity of flow networks.","PeriodicalId":501062,"journal":{"name":"arXiv - CS - Systems and Control","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140107315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Secure and Energy-efficient Unmanned Aerial Vehicle-enabled Visible Light Communication via A Multi-objective Optimization Approach","authors":"Lingling Liu, Aimin Wang, Jing Wu, Jiao Lu, Jiahui Li, Geng Sun","doi":"arxiv-2403.15410","DOIUrl":"https://doi.org/arxiv-2403.15410","url":null,"abstract":"In this research, a unique approach to provide communication service for\u0000terrestrial receivers via using unmanned aerial vehicle-enabled visible light\u0000communication is investigated. Specifically, we take into account a unmanned\u0000aerial vehicle-enabled visible light communication scenario with multiplex\u0000transmitters, multiplex receivers, and a single eavesdropper, each of which is\u0000equipped with a single photodetector. Then, a unmanned aerial vehicle\u0000deployment multi-objective optimization problem is formulated to simultaneously\u0000make the optical power received by receiving surface more uniform, minimize the\u0000amount of information collected by a eavesdropper, and minimize the energy\u0000consumption of unmanned aerial vehicles, while the locations and transmission\u0000power of unmanned aerial vehicles are simultaneously optimized under certain\u0000constraints. Since the formulated unmanned aerial vehicle deployment\u0000multi-objective optimization problem is complex and nonlinear, it is\u0000challenging to be tackled by using conventional methods. For the purpose of\u0000solving the problem, a multi-objective evolutionary algorithm based on\u0000decomposition with chaos initiation and crossover mutation is proposed.\u0000Simulation outcomes show that the proposed approach is superior to other\u0000approaches, and is efficient at improving the security and energy efficiency of\u0000visible light communication system.","PeriodicalId":501062,"journal":{"name":"arXiv - CS - Systems and Control","volume":"119 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140303357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Giulia Lafratta, Bernd Porr, Christopher Chandler, Alice Miller
{"title":"Homeostatic motion planning with innate physics knowledge","authors":"Giulia Lafratta, Bernd Porr, Christopher Chandler, Alice Miller","doi":"arxiv-2402.15384","DOIUrl":"https://doi.org/arxiv-2402.15384","url":null,"abstract":"Living organisms interact with their surroundings in a closed-loop fashion,\u0000where sensory inputs dictate the initiation and termination of behaviours. Even\u0000simple animals are able to develop and execute complex plans, which has not yet\u0000been replicated in robotics using pure closed-loop input control. We propose a\u0000solution to this problem by defining a set of discrete and temporary\u0000closed-loop controllers, called \"tasks\", each representing a closed-loop\u0000behaviour. We further introduce a supervisory module which has an innate\u0000understanding of physics and causality, through which it can simulate the\u0000execution of task sequences over time and store the results in a model of the\u0000environment. On the basis of this model, plans can be made by chaining\u0000temporary closed-loop controllers. The proposed framework was implemented for a\u0000real robot and tested in two scenarios as proof of concept.","PeriodicalId":501062,"journal":{"name":"arXiv - CS - Systems and Control","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139968540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Spatiotemporal Observer Design for Predictive Learning of High-Dimensional Data","authors":"Tongyi Liang, Han-Xiong Li","doi":"arxiv-2402.15284","DOIUrl":"https://doi.org/arxiv-2402.15284","url":null,"abstract":"Although deep learning-based methods have shown great success in\u0000spatiotemporal predictive learning, the framework of those models is designed\u0000mainly by intuition. How to make spatiotemporal forecasting with theoretical\u0000guarantees is still a challenging issue. In this work, we tackle this problem\u0000by applying domain knowledge from the dynamical system to the framework design\u0000of deep learning models. An observer theory-guided deep learning architecture,\u0000called Spatiotemporal Observer, is designed for predictive learning of high\u0000dimensional data. The characteristics of the proposed framework are twofold:\u0000firstly, it provides the generalization error bound and convergence guarantee\u0000for spatiotemporal prediction; secondly, dynamical regularization is introduced\u0000to enable the model to learn system dynamics better during training. Further\u0000experimental results show that this framework could capture the spatiotemporal\u0000dynamics and make accurate predictions in both one-step-ahead and\u0000multi-step-ahead forecasting scenarios.","PeriodicalId":501062,"journal":{"name":"arXiv - CS - Systems and Control","volume":"242 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139968508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}