1,720,963 research outputs found
AGV Traffic Management in Automated Industrial Plants: An Enhanced Lifelong Multi-Agent Path Finding Approach
No full textIn the context of Logistics 4.0, effective management of fleets of mobile agents in automated industrial plants is imperative to ensure productivity and enhance business flexibility. This study introduces an AGV traffic management system based on the Lifelong Multi-Agent Path Finding (L-MAPF) algorithm for the coordination of a fleet of AGVs. Unlike previous studies applied to a standardized grid-like environment, we focus on real-world industrial scenarios with bidirectional narrow corridors, where AGVs operate, moving on a roadmap. Our solution is based on a three-layer environment representation, i.e., a gridmap layer useful to represent the workspace of the AGVs, a roadmap layer employed to plan AGV paths, and a topological layer that divides the plant into different sectors, like corridors. For complete conflict resolution, we utilize our Bounded Horizon Conflict-Based Search, incorporating two innovative strategies for calculating corridor extension on the roadmap and expanding the time horizon within the corridor. The results of the tests conducted in a real industrial setting are presented and discussed in detail, demonstrating the effectiveness of our proposed method. Specifically, this methodology guarantees real-time AGV coordination and mitigates deadlock situations
Key Factors for Social Acceptance of Robots in the Industrial and Service Oriented Human-Robot Interaction Domains
No full textA literature review is conducted, presenting an overview of the crucial factors that impact the robots acceptance in the human-robot interaction (HRI) settings. In particular, our goal is to differentiate between factors whose measurement can be performed through indicators already available in the literature and those requiring additional efforts for quantification and incorporation into the design and control of robots. The key elements are categorized according to two primary categories, i.e., manufacturing and service. Within the manufacturing domain, six factors are identified: (perceived) occupational safety, physical ergonomics, cognitive ergonomics, efficiency, design, and privacy. Instead, within the service domain, four factors are acknowledged: safety, design, cognitive and emotional comfort, and privacy. The results of our review indicate that consistent effort is still required to define additional indices to quantify social acceptance of robots and improve their design in this perspective
A Literature Review on Control Techniques for Collaborative Robotics in Industrial Applications
No full textA Decentralized Noncooperative Control Approach for Sharing Energy Storage Systems in Energy Communities
No full textThis paper focuses on the optimal scheduling of the charging and discharging strategies of a community energy storage (CES) system, which is shared by the prosumers belonging to a grid-connected energy community. The prosumers own renewable energy sources (RESs), while they can buy/sell their energy imbalance directly from/to the power grid. For the sake of increasing the penetration of RESs and reducing the operating cost, prosumers leverage on the shared CES: in particular, each user can only employ a portion of the overall CES charge/discharge profile. Differently from the related literature, where storage devices are individually owned and the battery degradation aspects are typically disregarded, we propose a novel control mechanism based on noncooperative game theory, which allows users to minimize their energy cost as well as concur on the CES resources allocation with minimal-degradation. The effectiveness of the method is validated through numerical experiments on a realistic case study, where a shared CES supplies energy to the local community of residential prosumers. Finally, the comparison with a centralized control approach shows that the proposed framework allows all prosumers to achieve a fair cost-optimal utilization of the shared CES
A Multi-objective Optimization Approach for Trajectory Planning in a Safe and Ergonomic Human-Robot Collaboration
No full textIn today's manufacturing companies that rely on Human-Robot Collaboration (HRC), ensuring a safe and ergonomic workplace is becoming of pivotal importance. In a collaborative assembly scenario, this paper aims at planning the trajectory of a collaborative robotic arm, guaranteeing safety and ergonomics for the operator without neglecting production requirements. In particular, a multi-objective optimization approach for the trajectory planning in safe and ergonomic HRC is defined, with the aim of finding the best trade-off between the total traversal time of the trajectory for the robot and ergonomics for the human worker, while respecting safety requirements. The proposed approach consists of three main steps. First, the Rapid Upper Limb Assessment (RULA) ergonomic index is evaluated on a manikin designed on a dedicated software. The aim is to ensure a high quality of work in the considered HRC scenario with a consequent decrease of the musculoskeletal disorders associated with highly repetitive and dangerous activities. Second, a time-optimal and safety-constrained trajectory planning problem is defined as a second-order cone programming problem. Finally, a multi-objective control problem is formulated and solved to compute the trajectory that ensures the best compromise between time end ergonomics. The method is tested on numerical simulations and the obtained results are discussed, proving the effectiveness of the approach
Optimal Control of Drones for a Train-Drone Railway Diagnostic System
No full textThe inspection of railway systems with traditional wayside detectors allows mainly the detection of wheels and axle bearings defects and can be time-demanding, unsafe, and heavily dependent on humans. To overcome these issues and then optimize and automate the rail and track diagnosis process, drones can be an excellent solution thanks to their onboard state-of-the-art cameras and sensors. Thus, with the aim of rapidly collecting highly accurate data, an innovative hybrid movable railway diagnostic architecture, consisting of a diagnostic train and a fleet of drones, is defined in this work. From the control point of view, the main interest is in optimally managing the crucial phase of drones returning to and landing on the moving train when the railway inspection mission is completed. To control the fleet of drones, a combination of consensus algorithm in the leader-following mode and linear quadratic regulator (LQR) is implemented for the flight formation phase and the landing phase on the moving base platform (i.e., the diagnostic train), respectively. The landing phase is performed both as vertical or oblique descent through a go to goal and as oblique descent along a predefined path. The obtained results of the railway diagnostic architecture simulations are presented and discussed in detail. In particular, they show that the vertical and oblique descent performed as go to goal are certainly faster than the oblique descent along a predefined path
Automatic Control of Drones' Missions in a Hybrid Truck-Drone Delivery System
No full textLast-mile delivery is one of the most discussed problems of the last decade due to the growing importance of e-commerce and the development of Industry 4.0. In particular, this problem regards the delivery of parcels from the warehouse to the final customers. In order to bring efficiency and innovation, in this paper a hybrid delivery architecture is considered, which takes advantage of the combined use of a drone and a truck to perform a sequence of pick-ups and deliveries, and the problem of optimal control of the drones' missions is addressed. The reference scenario is the smart city where the drone of the hybrid delivery architecture is in charge of three different pick-up and delivery missions: truck to point (i.e., pick-up from the truck and delivery to the customer), point to point (i.e., delivery to a customer and pick-up from the subsequent customer), and point to truck (i.e., reentry from a customer to the truck). From the control point of view, the drone is optimally guided in all the operating modes, i.e., ascent and descent from/to truck mode, free flight mode with/without payload, and descent for pick-up/delivery mode, by a receding horizon linear quadratic regulator (LQR), which is able to manage the drone in the dynamic landing on a movable vehicle and to allow the changing in real time of the landing point on the truck. Simulation results of the truck-drone delivery architecture are presented and discussed in detail, proving the effectiveness of the proposed method
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
