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Robotics, Volume 12, Issue 3 (June 2023) – 28 articles

Cover Story (view full-size image): Human handwriting is an everyday task performed regularly by most people. In robotic painting, multiple calligraphy machines exist that were built to replicate some aspects of human artistic writing; however, most projects are limited to a specific style of handwriting. Our method allows industrial robots to write text in arbitrary typefaces and scripts using paintbrushes. We extract brushstrokes from glyphs and optimize the trajectories using a brush model. Our model computes brush pressure and accounts for brush lag. The model is automatically acquired from calibration strokes. Our method generates trajectories for text in any given typeface, which, when executed by a robotic arm, results in legible written text. We can render most writing systems, excluding emoji and ligatures, in which arbitrary texts can be written. View this paper
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13 pages, 10035 KiB  
Article
FastMimic: Model-Based Motion Imitation for Agile, Diverse and Generalizable Quadrupedal Locomotion
by Tianyu Li, Jungdam Won, Jeongwoo Cho, Sehoon Ha and Akshara Rai
Robotics 2023, 12(3), 90; https://doi.org/10.3390/robotics12030090 - 20 Jun 2023
Cited by 4 | Viewed by 2376
Abstract
Robots operating in human environments require a diverse set of skills, including slow and fast walking, turning, side-stepping, and more. However, developing robot controllers capable of exhibiting such a broad range of behaviors is a challenging problem that necessitates meticulous investigation for each [...] Read more.
Robots operating in human environments require a diverse set of skills, including slow and fast walking, turning, side-stepping, and more. However, developing robot controllers capable of exhibiting such a broad range of behaviors is a challenging problem that necessitates meticulous investigation for each task. To address this challenge, we introduce a trajectory optimization method that resolves the kinematic infeasibility of reference animal motions. This method, combined with a model-based controller, results in a unified data-driven model-based control framework capable of imitating various animal gaits without the need for expensive simulation training or real-world fine-tuning. Our framework is capable of imitating a variety of motor skills such as trotting, pacing, turning, and side-stepping with ease. It shows superior tracking capabilities in both simulations and the real world compared to other imitation controllers, including a model-based one and a learning-based motion imitation technique. Full article
(This article belongs to the Special Issue Legged Robots into the Real World)
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28 pages, 26199 KiB  
Article
A Study of Energy-Efficient and Optimal Locomotion in a Pneumatic Artificial Muscle-Driven Snake Robot
by Marcela Lopez and Mahdi Haghshenas-Jaryani
Robotics 2023, 12(3), 89; https://doi.org/10.3390/robotics12030089 - 20 Jun 2023
Cited by 4 | Viewed by 2734
Abstract
This paper presents a study of energy efficiency and kinematic-based optimal design locomotion of a pneumatic artificial muscle (PAM)-driven snake-like robot. Although snake-like robots have several advantages over wheeled and track-wheeled mobile robots, their low energy-locomotion has limited their applications in long-range and [...] Read more.
This paper presents a study of energy efficiency and kinematic-based optimal design locomotion of a pneumatic artificial muscle (PAM)-driven snake-like robot. Although snake-like robots have several advantages over wheeled and track-wheeled mobile robots, their low energy-locomotion has limited their applications in long-range and outdoor fields. This work continues our previous efforts in designing and prototyping a muscle-driven snake-like robot to address their low energy efficiency limitation. An electro-pneumatic control hardware was developed to control the robot’s locomotion and a control algorithm for generating the lateral undulation gait. The energy efficiency of a single muscle (i.e., PAM), a single 2-link module of the robot, and a 6-link snake robot were also studied. Moreover, the power consumption was derived for the snake locomotion to determine the cost of transportation as the index for measuring the performance of the robot. Finally, the performance of the robot was analyzed and compared to similar models. Our analysis showed that the power consumption efficiency for our robot is 0.21, which is comparable to the reported range of 0.016–0.32 from other robots. In addition, the cost of transportation for our robot was determined to be 0.19 compared to the range of 0.01–0.75 reported for the other mobile robots. Finally, the range of motion for the joints of the robot is ±30, which is comparable to the reported range of motion of other snake-like robots, i.e., 25–45. Full article
(This article belongs to the Special Issue Intelligent Bionic Robots)
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29 pages, 762 KiB  
Systematic Review
Keyframe Selection for Visual Localization and Mapping Tasks: A Systematic Literature Review
by Nigel Joseph Bandeira Dias, Gustavo Teodoro Laureano and Ronaldo Martins Da Costa
Robotics 2023, 12(3), 88; https://doi.org/10.3390/robotics12030088 - 15 Jun 2023
Cited by 6 | Viewed by 4673
Abstract
Visual localization and mapping algorithms attempt to estimate, from images, geometrical models that explain ego motion and the positions of objects in a real scene. The success of these tasks depends directly on the quality and availability of visual data, since the information [...] Read more.
Visual localization and mapping algorithms attempt to estimate, from images, geometrical models that explain ego motion and the positions of objects in a real scene. The success of these tasks depends directly on the quality and availability of visual data, since the information is recovered from visual changes in images. Keyframe selection is a commonly used approach to reduce the amount of data to be processed as well as to prevent useless or wrong information to be considered during the optimization. This study aims to identify, analyze, and summarize the methods present in the literature for keyframe selection within the context of visual localization and mapping. We adopt a systematic literature review (SLR) as the basis of our work, built on top of a well-defined methodology. To the best of our knowledge, this is the first review related to this topic. The results show that there is a lack of studies present in the literature that directly address the keyframe selection problem in this application context and a deficiency in the testing and validation of the proposed methods. In addition to these findings, we also propose an updated categorization of the proposed methods on top of the well-discussed categories present in the literature. We believe that this SLR is a step toward developing a body of knowledge in keyframe selection within the context of visual localization and mapping tasks by encouraging the development of more theoretical and less heuristic methods and a systematic testing and validation process. Full article
(This article belongs to the Section Sensors and Control in Robotics)
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10 pages, 43261 KiB  
Project Report
Performance Improvement of Multi-Robot Data Transmission in Aggregated Robot Processing Architecture with Caches and QoS Balancing Optimization
by Abdul Jalil, Jun Kobayashi and Takeshi Saitoh
Robotics 2023, 12(3), 87; https://doi.org/10.3390/robotics12030087 - 15 Jun 2023
Cited by 5 | Viewed by 3032
Abstract
Robot Operating System 2 (ROS 2) is a robotic software that uses a set of Quality of Service (QoS) policies to manage the quality of robot data transmissions in a network, such as the RELIABLE and KEEP_LAST options. In ROS 2 node communication, [...] Read more.
Robot Operating System 2 (ROS 2) is a robotic software that uses a set of Quality of Service (QoS) policies to manage the quality of robot data transmissions in a network, such as the RELIABLE and KEEP_LAST options. In ROS 2 node communication, the RELIABLE connection guarantees that all message data can be properly sent from the publisher to the subscriber. However, strict reliability is not guaranteed if the RELIABLE connection uses the KEEP_LAST option to transmit the robot data in the publish–subscribe communication. This study aims to analyze the efficiency of local cache, cache control, and QoS balancing optimization to improve ROS 2 node communication when using the RELIABLE and KEEP_LAST options to transmit multi-robot data in Aggregated Robot Processing (ARP) architecture. Our idea in local cache and cache control is to streamline the sensor data output before processing it when the sensor device produces the data with the same value in a row. Furthermore, QoS balancing optimization aims to balance the DEPTH and DEADLINE QoS configuration to determine the rates and buffer size in ROS 2 node communication. This study shows that combining local cache and QoS balancing optimization improves multi-robot data transmission and cooperation in ARP architecture. Full article
(This article belongs to the Special Issue Multi-robot Systems: State of the Art and Future Progress)
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20 pages, 1798 KiB  
Article
Online Feet Potential Fields for Quadruped Robots Navigation in Harsh Terrains
by Viviana Morlando, Jonathan Cacace and Fabio Ruggiero
Robotics 2023, 12(3), 86; https://doi.org/10.3390/robotics12030086 - 13 Jun 2023
Cited by 3 | Viewed by 2907
Abstract
Quadruped robots have garnered significant attention in recent years due to their ability to navigate through challenging terrains. Among the various environments, agriculture fields are particularly difficult for legged robots, given the variability of soil types and conditions. To address this issue, this [...] Read more.
Quadruped robots have garnered significant attention in recent years due to their ability to navigate through challenging terrains. Among the various environments, agriculture fields are particularly difficult for legged robots, given the variability of soil types and conditions. To address this issue, this study proposes a novel navigation strategy that utilizes ground reaction forces to calculate online artificial potential fields, which are then applied to the robot’s feet to avoid low-traversability regions. The strategy also incorporates the net vector of the attractive potential field towards the goal and the repulsive field to avoid slippery regions, which dynamically adjusts the quadruped’s gait. A realistic simulation environment validates the proposed navigation framework with case studies on randomly generated terrains. A comprehensive comparison with baseline navigation methods is conducted to assess the effectiveness of the proposed approach. Full article
(This article belongs to the Special Issue Legged Robots into the Real World)
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13 pages, 4008 KiB  
Article
Coordinating Tethered Autonomous Underwater Vehicles towards Entanglement-Free Navigation
by Abhishek Patil, Myoungkuk Park and Jungyun Bae
Robotics 2023, 12(3), 85; https://doi.org/10.3390/robotics12030085 - 13 Jun 2023
Viewed by 2093
Abstract
This paper proposes an algorithm that provides operational strategies for multiple tethered autonomous underwater vehicle (T-AUV) systems for entanglement-free navigation. T-AUVs can perform underwater tasks under reliable communication and power supply, which is the most substantial benefit of their operation. Thus, if one [...] Read more.
This paper proposes an algorithm that provides operational strategies for multiple tethered autonomous underwater vehicle (T-AUV) systems for entanglement-free navigation. T-AUVs can perform underwater tasks under reliable communication and power supply, which is the most substantial benefit of their operation. Thus, if one can overcome the entanglement issues while utilizing multiple tethered vehicles, the potential applications of the system increase including ecosystem exploration, infrastructure inspection, maintenance, search and rescue, underwater construction, and surveillance. In this study, we focus on developing strategies for task allocation, path planning, and scheduling that ensure entanglement-free operations while considering workload balancing among the vehicles. We do not impose restrictions on the size or shape of the vehicles at this stage; our primary focus is on efficient tether management as an initial work on the topic. To achieve entanglement-free navigation, we propose a heuristic based on the primal-dual technique, which enables initial task allocation and path planning while minimizing the maximum travel cost of the vehicles. Although this heuristic often generates sectioned paths due to its workload-balancing nature, we also propose a mixed approach to provide feasible solutions for non-sectioned initial paths. This approach combines entanglement avoidance techniques with time scheduling and sectionalization methods. To evaluate the effectiveness of our algorithm, extensive simulations were conducted with varying problem sizes. The computational results demonstrate the potential of our algorithm to be applied in real-time operations, as it consistently generates reliable solutions within a reasonable time frame. Full article
(This article belongs to the Special Issue Collection in Honor of Women's Contribution in Robotics)
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30 pages, 2651 KiB  
Review
Literature Review on Recent Trends and Perspectives of Collaborative Robotics in Work 4.0
by Carlo Weidemann, Nils Mandischer, Frederick van Kerkom, Burkhard Corves, Mathias Hüsing, Thomas Kraus and Cyryl Garus
Robotics 2023, 12(3), 84; https://doi.org/10.3390/robotics12030084 - 7 Jun 2023
Cited by 16 | Viewed by 13015
Abstract
This literature review presents a comprehensive analysis of the use and potential application scenarios of collaborative robots in the industrial working world, focusing on their impact on human work, safety, and health in the context of Industry 4.0. The aim is to provide [...] Read more.
This literature review presents a comprehensive analysis of the use and potential application scenarios of collaborative robots in the industrial working world, focusing on their impact on human work, safety, and health in the context of Industry 4.0. The aim is to provide a holistic evaluation of the employment of collaborative robots in the current and future working world, which is being increasingly driven by the automation and digitization of production processes, and which can be outlined using the term Work 4.0. In this context, the forms of work organization, and the demands and impacts on humans are changing profoundly. Collaborative robots represent a key technology to aid the transition. The review utilizes expert interviews for identifying relevant keywords, and follows the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) framework to evaluate peer-reviewed literature between 2002 and January 2022. The analysis includes forms of interaction, and the distribution of roles, control interfaces, safety procedures, and ergonomics and health. In addition, the review offers a heatmap displaying the research topics of 715 publications for each year, and a database of these publications in BibTeX format that is publicly accessible. The review highlights the challenges, potential benefits, and trends of using collaborative robots in the industrial working world, emphasizing the importance of a careful evaluation of their impact on human work, safety, and health. It offers a tool set for researchers and practitioners to further explore and evaluate the employment of collaborative robots in Work 4.0. Full article
(This article belongs to the Section Industrial Robots and Automation)
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25 pages, 5401 KiB  
Article
Finger Joint Stiffness Estimation with Joint Modular Soft Actuators for Hand Telerehabilitation
by Fuko Matsunaga, Shota Kokubu, Pablo Enrique Tortos Vinocour, Ming-Ta Ke, Ya-Hsin Hsueh, Shao Ying Huang, Jose Gomez-Tames and Wenwei Yu
Robotics 2023, 12(3), 83; https://doi.org/10.3390/robotics12030083 - 7 Jun 2023
Cited by 7 | Viewed by 2910
Abstract
In a telerehabilitation environment, it is difficult for a therapist to understand the condition of a patient’s finger joints because of the lack of direct assessment. In particular, not enabling the provision of spasticity evaluation significantly reduces the optimal performance of telerehabilitation. In [...] Read more.
In a telerehabilitation environment, it is difficult for a therapist to understand the condition of a patient’s finger joints because of the lack of direct assessment. In particular, not enabling the provision of spasticity evaluation significantly reduces the optimal performance of telerehabilitation. In a previous study, it has been proposed that finger stiffness could be estimated using an analytical model of a whole-finger soft actuator. However, because the whole-finger soft actuators require high air pressure for high bending performance and are costly to customize for each patient, using joint modular soft actuators for telerehabilitation turns to be a necessity, though stiffness estimation with joint modular soft actuators has not been studied yet. Another problem is caused by using a marker-based joint angle measurement, which requires the markers to be attached to the exact positions, and limits its application in telerehabilitation. In this study, we proposed a procedure of finger joint stiffness estimation that combines information acquired from a joint modular soft actuator and a marker-less hand joint position acquisition device. Correction parameters were added to the previous analytical model for -the bending analysis of a joint assisted using a joint modular soft actuator. Moreover, a multi-variate regression model was implemented for correcting joint angles obtained from the hand joint position acquisition device. As a result, a reasonable accuracy of stiffness estimation was achieved for rehabilitation with the joint modular soft actuators, which suggests the possibility of using the proposed method to evaluate the finger spasticity in a telerehabilitation environment. This is a big step forward towards optimal hand telerehabilitation. Full article
(This article belongs to the Special Issue The State-of-the-Art of Robotics in Asia)
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27 pages, 14012 KiB  
Article
Mechanical Design of a Biped Robot FORREST and an Extended Capture-Point-Based Walking Pattern Generator
by Hongxi Zhu and Ulrike Thomas
Robotics 2023, 12(3), 82; https://doi.org/10.3390/robotics12030082 - 7 Jun 2023
Cited by 3 | Viewed by 4045
Abstract
In recent years, many studies have shown that soft robots with elastic actuators enable robust interaction with the environment. Compliant joints can protect mechanical systems and provide better dynamic performance, thus offering huge potential for further developments of humanoid robots. This paper proposes [...] Read more.
In recent years, many studies have shown that soft robots with elastic actuators enable robust interaction with the environment. Compliant joints can protect mechanical systems and provide better dynamic performance, thus offering huge potential for further developments of humanoid robots. This paper proposes a new biped robot. The new robot combines a torque sensor-based active elastic hip and a spring-based passive elastic knee/ankle. In the first part, the mechanical design is introduced, and in the second part, the kinematics and dynamics capabilities are described. Furthermore, we introduce a new extended capture-point-based walking pattern generator that calculates footstep positions, which are used as input for the controller of our new biped robot. The main contribution of this article is the novel mechanical design and an extended walking pattern generator. The new design offers a unique solution for cable-driven bipeds to achieve both balancing and walking. Meanwhile, the new walking pattern generator can generate smooth desired curves, which is an improvement over traditional generators that use a constant zero-moment-point (ZMP). A simple cartesian controller is applied to test the performance of the walking pattern generator. Although the robot has been built, all experiments regarding the pattern generator are still simulated using MATLAB/Simulink. The focus of this work is to analyze the mechanical design and show the capabilities of the robot by applying a new pattern generator. Full article
(This article belongs to the Special Issue Kinematics and Robot Design V, KaRD2022)
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15 pages, 5918 KiB  
Article
Experiments on the Artificial Potential Field with Local Attractors for Mobile Robot Navigation
by Matteo Melchiorre, Laura Salamina, Leonardo Sabatino Scimmi, Stefano Mauro and Stefano Pastorelli
Robotics 2023, 12(3), 81; https://doi.org/10.3390/robotics12030081 - 7 Jun 2023
Cited by 9 | Viewed by 2204
Abstract
Obstacle avoidance is a challenging task in robot navigation, as it requires efficient and reliable methods to avoid collision and reach the desired goal. Artificial potential field methods are widely used for this purpose, as they are efficient, effective, and easy to implement. [...] Read more.
Obstacle avoidance is a challenging task in robot navigation, as it requires efficient and reliable methods to avoid collision and reach the desired goal. Artificial potential field methods are widely used for this purpose, as they are efficient, effective, and easy to implement. However, they are limited by the use of only one global attractor at the goal. This paper introduces and evaluates experimentally a novel technique that enhances the artificial potential field method with local attractors. Local attractors can be positioned around the obstacle so as to guide the robot detouring through preferred regions. Thus, the side the robot will pass by can be determined in advance, making the collision-free path predictable. The technique is formulated by modelling local attractors as optimal inflections, i.e., regions that do not show local minima, which coexist with the potential field generated by the obstacle and the global attractor. The method is validated using a laboratory setup that employs a camera and markers to track the poses of the robot, the obstacle, and the target. A series of experiments are conducted to examine the effect of the local attractor under different test conditions, obtained by varying the obstacle pose, the attraction intensity, and the robot velocity. The experimental results demonstrate the effectiveness of the proposed technique and highlight the aspects that require further investigation for its improvement and application. Full article
(This article belongs to the Special Issue Collection in Honor of Women's Contribution in Robotics)
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15 pages, 6890 KiB  
Article
Variable Damping Actuator Using an Electromagnetic Brake for Impedance Modulation in Physical Human–Robot Interaction
by Zahid Ullah, Ronnapee Chaichaowarat and Witaya Wannasuphoprasit
Robotics 2023, 12(3), 80; https://doi.org/10.3390/robotics12030080 - 4 Jun 2023
Cited by 11 | Viewed by 2679
Abstract
Compliance actuation systems are efficient and safe, drawing attention to their development. However, compliance has caused bandwidth loss, instability, and mechanical vibration in robotic systems. Variable physical damping was introduced to address these issues. This paper presents a technique for obtaining variable damping [...] Read more.
Compliance actuation systems are efficient and safe, drawing attention to their development. However, compliance has caused bandwidth loss, instability, and mechanical vibration in robotic systems. Variable physical damping was introduced to address these issues. This paper presents a technique for obtaining variable damping properties using an electromagnetic brake. The relationship mapping of the voltage and the braking torque is studied and applied to the variable damping concept. A new model is proposed to demonstrate the actuation system performance gained by introducing physical damping. The experimental setup comprises an electromagnetic brake and a motor with an integrated controller for speed control and torque feedback. The motor provides the motion, while the electromagnetic brake replicates the damping through a friction mechanism. The variable damping concept was evaluated experimentally using a 1-degree-of-freedom rotational system. Experimental results show that the proposed concept can generate the desired mechanical damping with a high degree of fidelity. Full article
(This article belongs to the Topic Safe and Secure Autonomous Systems)
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33 pages, 1617 KiB  
Review
COBOT Applications—Recent Advances and Challenges
by Claudio Taesi, Francesco Aggogeri and Nicola Pellegrini
Robotics 2023, 12(3), 79; https://doi.org/10.3390/robotics12030079 - 4 Jun 2023
Cited by 24 | Viewed by 10710
Abstract
This study provides a structured literature review of the recent COllaborative roBOT (COBOT) applications in industrial and service contexts. Several papers and research studies were selected and analyzed, observing the collaborative robot interactions, the control technologies and the market impact. This review focuses [...] Read more.
This study provides a structured literature review of the recent COllaborative roBOT (COBOT) applications in industrial and service contexts. Several papers and research studies were selected and analyzed, observing the collaborative robot interactions, the control technologies and the market impact. This review focuses on stationary COBOTs that may guarantee flexible applications, resource efficiency, and worker safety from a fixed location. COBOTs offer new opportunities to develop and integrate control techniques, environmental recognition of time-variant object location, and user-friendly programming to interact safely with humans. Artificial Intelligence (AI) and machine learning systems enable and boost the COBOT’s ability to perceive its surroundings. A deep analysis of different applications of COBOTs and their properties, from industrial assembly, material handling, service personal assistance, security and inspection, Medicare, and supernumerary tasks, was carried out. Among the observations, the analysis outlined the importance and the dependencies of the control interfaces, the intention recognition, the programming techniques, and virtual reality solutions. A market analysis of 195 models was developed, focusing on the physical characteristics and key features to demonstrate the relevance and growing interest in this field, highlighting the potential of COBOT adoption based on (i) degrees of freedom, (ii) reach and payload, (iii) accuracy, and (iv) energy consumption vs. tool center point velocity. Finally, a discussion on the advantages and limits is summarized, considering anthropomorphic robot applications for further investigations. Full article
(This article belongs to the Special Issue The State-of-the-Art of Robotics in Europe)
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16 pages, 5225 KiB  
Article
Path Following for an Omnidirectional Robot Using a Non-Linear Model Predictive Controller for Intelligent Warehouses
by Rocco Galati and Giacomo Mantriota
Robotics 2023, 12(3), 78; https://doi.org/10.3390/robotics12030078 - 29 May 2023
Cited by 8 | Viewed by 2166
Abstract
This paper presents results coming from a non-linear model predictive controller used to generate optimized trajectories specifically for an omnidirectional robot equipped with a spraying unit to mark on the floor the perimeter of dangerous areas or to move large palletized goods inside [...] Read more.
This paper presents results coming from a non-linear model predictive controller used to generate optimized trajectories specifically for an omnidirectional robot equipped with a spraying unit to mark on the floor the perimeter of dangerous areas or to move large palletized goods inside warehouses. Results on different trajectories and with moving obstacles are provided along with considerations on the controller performance. Full article
(This article belongs to the Special Issue Robotics and AI for Precision Agriculture)
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16 pages, 9414 KiB  
Article
AutoDRIVE: A Comprehensive, Flexible and Integrated Digital Twin Ecosystem for Autonomous Driving Research & Education
by Tanmay Samak, Chinmay Samak, Sivanathan Kandhasamy, Venkat Krovi and Ming Xie
Robotics 2023, 12(3), 77; https://doi.org/10.3390/robotics12030077 - 26 May 2023
Cited by 9 | Viewed by 5044
Abstract
Prototyping and validating hardware–software components, sub-systems and systems within the intelligent transportation system-of-systems framework requires a modular yet flexible and open-access ecosystem. This work presents our attempt to develop such a comprehensive research and education ecosystem, called AutoDRIVE, for synergistically prototyping, simulating and [...] Read more.
Prototyping and validating hardware–software components, sub-systems and systems within the intelligent transportation system-of-systems framework requires a modular yet flexible and open-access ecosystem. This work presents our attempt to develop such a comprehensive research and education ecosystem, called AutoDRIVE, for synergistically prototyping, simulating and deploying cyber-physical solutions pertaining to autonomous driving as well as smart city management. AutoDRIVE features both software as well as hardware-in-the-loop testing interfaces with openly accessible scaled vehicle and infrastructure components. The ecosystem is compatible with a variety of development frameworks, and supports both single- and multi-agent paradigms through local as well as distributed computing. Most critically, AutoDRIVE is intended to be modularly expandable to explore emergent technologies, and this work highlights various complementary features and capabilities of the proposed ecosystem by demonstrating four such deployment use-cases: (i) autonomous parking using probabilistic robotics approach for mapping, localization, path-planning and control; (ii) behavioral cloning using computer vision and deep imitation learning; (iii) intersection traversal using vehicle-to-vehicle communication and deep reinforcement learning; and (iv) smart city management using vehicle-to-infrastructure communication and internet-of-things. Full article
(This article belongs to the Special Issue Mechatronics Systems and Robots)
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17 pages, 5016 KiB  
Article
Non-Commutative Logic for Collective Decision-Making with Perception Bias
by Evgeny Kagan, Alexander Novoselsky, Daria Ramon and Alexander Rybalov
Robotics 2023, 12(3), 76; https://doi.org/10.3390/robotics12030076 - 22 May 2023
Cited by 1 | Viewed by 1639
Abstract
In this paper, we suggest an implementation of non-commutative logic and apply its operators for decision-making in a group of autonomous agents. The suggested operators extend the uninorm and absorbing norm aggregators and use an additional asymmetry parameter that defines the “level of [...] Read more.
In this paper, we suggest an implementation of non-commutative logic and apply its operators for decision-making in a group of autonomous agents. The suggested operators extend the uninorm and absorbing norm aggregators and use an additional asymmetry parameter that defines the “level of non-commutativity”. The value of this parameter is specified using the perception bias of humans measured in the experiments. The suggested operators and decision-making method are illustrated by the simulated behavior of mobile robots in the group, which verified the possibility of processing systematic sensing errors, as well as of distinguishing and mimicking the biased decisions. Full article
(This article belongs to the Special Issue Multi-robot Systems: State of the Art and Future Progress)
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21 pages, 7177 KiB  
Article
Development and Experimental Studies of a Method Based on a Reference Control Signal Generating System for Redundant Serial Manipulators
by Vladimir Filaretov, Anton Gubankov and Igor Gornostaev
Robotics 2023, 12(3), 75; https://doi.org/10.3390/robotics12030075 - 19 May 2023
Viewed by 1657
Abstract
The paper presents the design and experimental study of a synthesis method based on reference signal generation systems. The method can be used for all actuators of redundant manipulators. The aforementioned systems aim to save the dynamic control accuracy of the working tools [...] Read more.
The paper presents the design and experimental study of a synthesis method based on reference signal generation systems. The method can be used for all actuators of redundant manipulators. The aforementioned systems aim to save the dynamic control accuracy of the working tools of serial manipulators when they move along arbitrary spatial trajectories, taking into account restrictions in all degrees of freedom and special cases of their link positions. The maintenance of the control accuracy could be ensured by eliminating the reach of all degrees of freedom of manipulators to their limits and to indicated special positions, characterized by an ambiguity when solving the inverse kinematic problems of various serial manipulators. This is in addition to preventing the reach of their working tools to the boundaries of the working area due to the use of a redundant degree of freedom when approaching the indicated undesirable positions. The experimental studies performed in this paper confirm the efficiency of the proposed method and allow accurate characteristics to be obtained. Full article
(This article belongs to the Section Industrial Robots and Automation)
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37 pages, 27143 KiB  
Review
Watch the Next Step: A Comprehensive Survey of Stair-Climbing Vehicles
by Antonio Pappalettera, Francesco Bottiglione, Giacomo Mantriota and Giulio Reina
Robotics 2023, 12(3), 74; https://doi.org/10.3390/robotics12030074 - 18 May 2023
Cited by 5 | Viewed by 3409
Abstract
Stair climbing is one of the most challenging tasks for vehicles, especially when transporting people and heavy loads. Although many solutions have been proposed and demonstrated in practice, it is necessary to further improve their climbing ability and safety. This paper presents a [...] Read more.
Stair climbing is one of the most challenging tasks for vehicles, especially when transporting people and heavy loads. Although many solutions have been proposed and demonstrated in practice, it is necessary to further improve their climbing ability and safety. This paper presents a systematic review of the scientific and engineering stair climbing literature, providing brief descriptions of the mechanism and method of operation and highlighting the advantages and disadvantages of different types of climbing platform. To quantitatively evaluate the system performance, various metrics are presented that consider allowable payload, maximum climbing speed, maximum crossable slope, transport ability and their combinations. Using these metrics, it is possible to compare vehicles with different locomotion modes and properties, allowing researchers and practitioners to gain in-depth knowledge of stair-climbing vehicles and choose the best category for transporting people and heavy loads up a flight of stairs. Full article
(This article belongs to the Special Issue Robotics and AI for Precision Agriculture)
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17 pages, 4484 KiB  
Article
Hybrid Vibration Control Algorithm of a Flexible Manipulator System
by Van Binh Nguyen and Xuan Cuong Bui
Robotics 2023, 12(3), 73; https://doi.org/10.3390/robotics12030073 - 15 May 2023
Cited by 5 | Viewed by 2303
Abstract
Flexible manipulator systems in specific applications such as space exploration, nuclear waste treatment, medical applications, etc., often have characteristics superior to conventional rigid manipulator systems. However, their elasticity and complex dynamics lead to difficulties encountered in control processes. Research on improving the structure [...] Read more.
Flexible manipulator systems in specific applications such as space exploration, nuclear waste treatment, medical applications, etc., often have characteristics superior to conventional rigid manipulator systems. However, their elasticity and complex dynamics lead to difficulties encountered in control processes. Research on improving the structure of the control model plays a very important role in reducing the above limitations and achieving great benefits for the flexible manipulator system. In this study, a general method for modelling a flexible robotic manipulator is introduced. Furthermore, two control models for flexible manipulators are proposed. The first model uses two proportional–integral–derivative (PID) controllers, where the first one is used for position control, and the other is applied for vibration reduction. The second model is an enhanced development of the first with the addition of a fuzzy logic controller to optimise oscillation suppression. Selected experimental results are presented and compared to evaluate the performance of the proposed control mechanisms. Full article
(This article belongs to the Topic Intelligent Systems and Robotics)
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17 pages, 5657 KiB  
Article
Robotic Writing of Arbitrary Unicode Characters Using Paintbrushes
by David Silvan Zingrebe, Jörg Marvin Gülzow and Oliver Deussen
Robotics 2023, 12(3), 72; https://doi.org/10.3390/robotics12030072 - 11 May 2023
Cited by 1 | Viewed by 2372
Abstract
Human handwriting is an everyday task performed regularly by most people. In the domain of robotic painting, multiple calligraphy machines exist which were built to replicate some aspects of human artistic writing; however, most projects are limited to a specific style of handwriting, [...] Read more.
Human handwriting is an everyday task performed regularly by most people. In the domain of robotic painting, multiple calligraphy machines exist which were built to replicate some aspects of human artistic writing; however, most projects are limited to a specific style of handwriting, often Chinese calligraphy. We propose a two-stage pipeline that allows industrial robots to write text in arbitrary typefaces and scripts using paintbrushes. In the first stage, we extract a set of strokes from character glyphs which are similar to how humans choose strokes during writing. In the second stage, we generate corresponding brush trajectories by applying a brush model to the extracted strokes. Our brush model computes the required brush pressure to achieve the given stroke width while also accounting for brush lag. We also present a method to automatically measure the parameters needed to predict brush lag by painting and recording calibration patterns. Our method generates trajectories for text in any given typeface, which, when executed by a robotic arm, results in legible written text. We can render most writing systems, excluding emoji and ligatures, in which arbitrary texts can be specified to write. Full article
(This article belongs to the Section Sensors and Control in Robotics)
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22 pages, 10727 KiB  
Article
A Comprehensive Multibody Model of a Collaborative Robot to Support Model-Based Health Management
by Andrea Raviola, Roberto Guida, Antonio Carlo Bertolino, Andrea De Martin, Stefano Mauro and Massimo Sorli
Robotics 2023, 12(3), 71; https://doi.org/10.3390/robotics12030071 - 9 May 2023
Cited by 9 | Viewed by 4581
Abstract
Digital models of industrial and collaborative manipulators are widely used for several applications, such as power-efficient trajectory definition, human–robot cooperation safety improvement, and prognostics and health management (PHM) algorithm development. Currently, models with simplified joints present in the literature have been used to [...] Read more.
Digital models of industrial and collaborative manipulators are widely used for several applications, such as power-efficient trajectory definition, human–robot cooperation safety improvement, and prognostics and health management (PHM) algorithm development. Currently, models with simplified joints present in the literature have been used to evaluate robot macroscopic behavior. However, they are not suitable for the in-depth analyses required by those activities, such as PHM, which demand a punctual description of each subcomponent. This paper aims to fill this gap by presenting a high-fidelity multibody model of a UR5 collaborative robot, containing an accurate description of its full dynamics, electric motors, and gearboxes. Harmonic reducers were described through a translational equivalent lumped parameter model, allowing each constitutive element of the reducer to have its decoupled dynamics and mating forces through non-linear penalty contact models. To conclude, both the mathematical model and the real robot on a test rig were tested with a set of different trajectories. The experimental results highlight the ability of the proposed model to accurately replicate joint angular rotation, speed and torques in a wide range of operational scenarios. This research provides the basis for the development of a model-based PHM-oriented framework to carry out detailed and advanced analyses on the effects of manipulator degradations. Full article
(This article belongs to the Section Industrial Robots and Automation)
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29 pages, 7249 KiB  
Article
Occupancy Grid Mapping via Resource-Constrained Robotic Swarms: A Collaborative Exploration Strategy
by Andrew Rogers, Kasra Eshaghi, Goldie Nejat and Beno Benhabib
Robotics 2023, 12(3), 70; https://doi.org/10.3390/robotics12030070 - 9 May 2023
Cited by 3 | Viewed by 2646
Abstract
This paper addresses the problem of building an occupancy grid map of an unknown environment using a swarm comprising resource-constrained robots, i.e., robots with limited exteroceptive and inter-robot sensing capabilities. Past approaches have, commonly, used random-motion models to disperse the swarm and explore [...] Read more.
This paper addresses the problem of building an occupancy grid map of an unknown environment using a swarm comprising resource-constrained robots, i.e., robots with limited exteroceptive and inter-robot sensing capabilities. Past approaches have, commonly, used random-motion models to disperse the swarm and explore the environment randomly, which do not necessarily consider prior information already contained in the map. Herein, we present a collaborative, effective exploration strategy that directs the swarm toward ‘promising’ frontiers by dividing the swarm into two teams: landmark robots and mapper robots, respectively. The former direct the latter, toward promising frontiers, to collect proximity measurements to be incorporated into the map. The positions of the landmark robots are optimized to maximize new information added to the map while also adhering to connectivity constraints. The proposed strategy is novel as it decouples the problem of directing the resource-constrained swarm from the problem of mapping to build an occupancy grid map. The performance of the proposed strategy was validated through extensive simulated experiments. Full article
(This article belongs to the Special Issue The State of the Art of Swarm Robotics)
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28 pages, 22741 KiB  
Article
Process of Learning from Demonstration with Paraconsistent Artificial Neural Cells for Application in Linear Cartesian Robots
by João Inácio Da Silva Filho, Cláudio Luís Magalhães Fernandes, Rodrigo Silvério da Silveira, Paulino Machado Gomes, Sérgio Luiz da Conceição Matos, Leonardo do Espirito Santo, Vander Célio Nunes, Hyghor Miranda Côrtes, William Aparecido Celestino Lopes, Mauricio Conceição Mario, Dorotéa Vilanova Garcia, Cláudio Rodrigo Torres, Jair Minoro Abe and Germano Lambert-Torres
Robotics 2023, 12(3), 69; https://doi.org/10.3390/robotics12030069 - 6 May 2023
Cited by 1 | Viewed by 2635
Abstract
Paraconsistent Annotated Logic (PAL) is a type of non-classical logic based on concepts that allow, under certain conditions, for one to accept contradictions without invalidating conclusions. The Paraconsistent Artificial Neural Cell of Learning (lPANCell) algorithm was created from PAL-based equations. With [...] Read more.
Paraconsistent Annotated Logic (PAL) is a type of non-classical logic based on concepts that allow, under certain conditions, for one to accept contradictions without invalidating conclusions. The Paraconsistent Artificial Neural Cell of Learning (lPANCell) algorithm was created from PAL-based equations. With its procedures for learning discrete patterns being represented by values contained in the closed interval between 0 and 1, the lPANCell algorithm presents responses similar to those of nonlinear dynamical systems. In this work, several tests were carried out to validate the operation of the lPANCell algorithm in a learning from demonstration (LfD) framework applied to a linear Cartesian robot (gantry robot), which was moving rectangular metallic workpieces. For the LfD process used in the teaching of trajectories in the x and y axes of the linear Cartesian robot, a Paraconsistent Artificial Neural Network (lPANnet) was built, which was composed of eight lPANCells. The results showed that lPANnet has dynamic properties with a robustness to disturbances, both in the learning process by demonstration, as well as in the imitation process. Based on this work, paraconsistent artificial neural networks of a greater complexity, which are composed of lPANCells, can be formed. This study will provide a strong contribution to research regarding learning from demonstration frameworks being applied in robotics. Full article
(This article belongs to the Section AI in Robotics)
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23 pages, 1973 KiB  
Review
Robotics: Five Senses plus One—An Overview
by Rand N. Albustanji, Shorouq Elmanaseer and Ahmad A. A. Alkhatib
Robotics 2023, 12(3), 68; https://doi.org/10.3390/robotics12030068 - 4 May 2023
Cited by 14 | Viewed by 17199
Abstract
Robots can be equipped with a range of senses to allow them to perceive and interact with the world in a more natural and intuitive way. These senses can include vision, hearing, touch, smell, and taste. Vision allows the robot to see and [...] Read more.
Robots can be equipped with a range of senses to allow them to perceive and interact with the world in a more natural and intuitive way. These senses can include vision, hearing, touch, smell, and taste. Vision allows the robot to see and recognize objects and navigate its environment. Hearing enables the robot to recognize sounds and respond to vocal commands. Touch allows the robot to perceive information about the texture, shape, and temperature of objects through the sense of touch. Smell enables the robot to recognize and classify different odors. Taste enables the robot to identify the chemical composition of materials. The specific senses used in a robot will depend on the needs of the application, and many robots use a combination of different senses to perceive and interact with the environment. This paper reviews the five senses used in robots, their types, how they work, and other related information, while also discussing the possibility of a Sixth Sense. Full article
(This article belongs to the Section Sensors and Control in Robotics)
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18 pages, 3033 KiB  
Article
A Data-Driven Model Predictive Control for Quadruped Robot Steering on Slippery Surfaces
by Paolo Arena, Luca Patanè and Salvatore Taffara
Robotics 2023, 12(3), 67; https://doi.org/10.3390/robotics12030067 - 1 May 2023
Cited by 4 | Viewed by 3723
Abstract
In this paper, the locomotion and steering control of a simulated Mini Cheetah quadruped robot was investigated in the presence of terrain characterised by low friction. Low-level locomotion and steering control were implemented via a central pattern generator approach, whereas high-level steering control [...] Read more.
In this paper, the locomotion and steering control of a simulated Mini Cheetah quadruped robot was investigated in the presence of terrain characterised by low friction. Low-level locomotion and steering control were implemented via a central pattern generator approach, whereas high-level steering control manoeuvres were implemented by comparing a neural network and a linear model predictive controller in a dynamic simulation environment. A data-driven approach was adopted to identify the robot model using both a linear transfer function and a shallow artificial neural network. The results demonstrate that, whereas the linear approach showed good performance in high-friction terrain, in the presence of slippery conditions, the application of a neural network predictive controller improved trajectory accuracy and preserved robot safety with different steering manoeuvres. A comparative analysis was carried out using several performance indices. Full article
(This article belongs to the Special Issue Legged Robots into the Real World)
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12 pages, 2566 KiB  
Article
Human–Exoskeleton Interaction Force Estimation in Indego Exoskeleton
by Mohammad Shushtari and Arash Arami
Robotics 2023, 12(3), 66; https://doi.org/10.3390/robotics12030066 - 1 May 2023
Cited by 6 | Viewed by 2725
Abstract
Accurate interaction force estimation can play an important role in optimizing human–robot interaction in an exoskeleton. In this work, we propose a novel approach for the system identification of exoskeleton dynamics in the presence of interaction forces as a whole multibody system without [...] Read more.
Accurate interaction force estimation can play an important role in optimizing human–robot interaction in an exoskeleton. In this work, we propose a novel approach for the system identification of exoskeleton dynamics in the presence of interaction forces as a whole multibody system without imposing any constraints on the exoskeleton dynamics. We hung the exoskeleton through a linear spring and excited the exoskeleton joints with chirp commands while measuring the exoskeleton–environment interaction force. Several structures of neural networks were trained to model the exoskeleton passive dynamics and estimate the interaction force. Our testing results indicated that a deep neural network with 250 neurons and 10 time–delays could obtain a sufficiently accurate estimation of the interaction force, resulting in an RMSE of 1.23 on Z–normalized applied torques and an adjusted R2 of 0.89. Full article
(This article belongs to the Special Issue Human Factors in Human–Robot Interaction)
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17 pages, 19083 KiB  
Article
Robot Localization Using Situational Graphs (S-Graphs) and Building Architectural Plans
by Muhammad Shaheer, Hriday Bavle, Jose Luis Sanchez-Lopez and Holger Voos
Robotics 2023, 12(3), 65; https://doi.org/10.3390/robotics12030065 - 28 Apr 2023
Cited by 1 | Viewed by 2262
Abstract
This paper presents robot localization using building architectural plans and hierarchical SLAM. We extract geometric, semantic as well as topological information from the architectural plans in the form of walls and rooms, and create the topological and metric-semantic layer of the Situational Graphs [...] Read more.
This paper presents robot localization using building architectural plans and hierarchical SLAM. We extract geometric, semantic as well as topological information from the architectural plans in the form of walls and rooms, and create the topological and metric-semantic layer of the Situational Graphs (S-Graphs) before navigating in the environment. When the robot navigates in the construction environment, it uses the robot odometry and 3D lidar measurements to extract planar wall surfaces. A particle filter method exploits the previously built situational graph and its available geometric, semantic, and topological information to perform global localization. We validate our approach in simulated and real datasets captured on ongoing construction sites presenting state-of-the-art results when comparing it against traditional geometry-based localization techniques. Full article
(This article belongs to the Section Sensors and Control in Robotics)
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24 pages, 2053 KiB  
Article
An Optimal Control Approach to the Minimum-Time Trajectory Planning of Robotic Manipulators
by Matteo Massaro, Stefano Lovato, Matteo Bottin and Giulio Rosati
Robotics 2023, 12(3), 64; https://doi.org/10.3390/robotics12030064 - 28 Apr 2023
Cited by 4 | Viewed by 3877
Abstract
Trajectory planning is a classic problem in robotics, with different approaches and optimisation objectives documented in the literature. Most of the time, the path is assumed, i.e., pre-defined, and optimisation consists of finding the timing of motion under a number of constraints. The [...] Read more.
Trajectory planning is a classic problem in robotics, with different approaches and optimisation objectives documented in the literature. Most of the time, the path is assumed, i.e., pre-defined, and optimisation consists of finding the timing of motion under a number of constraints. The focus of this work is on the minimum-time manoeuvring of robotic manipulators. A nonlinear optimal control approach is proposed that does not require the provision of either a pre-defined path or a pre-defined control structure and allows the inclusion of dynamic constraints. The solution (path and timing of motion) is obtained by transforming the optimal control problem into a nonlinear programming problem. The proposed approach is applied to a two-link manipulator for illustration purposes. The optimisation is carried out both without and with obstacles. The minimum-distance and minimum-time solutions are compared, and some classic results are obtained, including the trapezoidal pattern of the joint velocity and the bang–bang structure of the control torques. The effects of limitations on the jerks of actuators and the rate of change in torque inputs are discussed. The application to a four-link manipulator is also included to show the ‘scalability’ of the approach, together with a comparison with a classic path-and-motion-planning method, to highlight the characteristics and performance of the proposed approach. Finally, the possibility of enforcing a number of via-points along the path is demonstrated. The proposed method allows the computation of the path and motion simultaneously with the computation time, which is 1–30 times the manoeuvre time, on a standard PC with the current implementation. Full article
(This article belongs to the Topic Industrial Robotics: 2nd Volume)
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21 pages, 1376 KiB  
Article
Towards Safe Robotic Agricultural Applications: Safe Navigation System Design for a Robotic Grass-Mowing Application through the Risk Management Method
by José Carlos Mayoral Baños, Pål Johan From and Grzegorz Cielniak
Robotics 2023, 12(3), 63; https://doi.org/10.3390/robotics12030063 - 23 Apr 2023
Cited by 5 | Viewed by 2692
Abstract
Safe navigation is a key objective for autonomous applications, particularly those involving mobile tasks, to avoid dangerous situations and prevent harm to humans. However, the integration of a risk management process is not yet mandatory in robotics development. Ensuring safety using mobile robots [...] Read more.
Safe navigation is a key objective for autonomous applications, particularly those involving mobile tasks, to avoid dangerous situations and prevent harm to humans. However, the integration of a risk management process is not yet mandatory in robotics development. Ensuring safety using mobile robots is critical for many real-world applications, especially those in which contact with the robot could result in fatal consequences, such as agricultural environments where a mobile device with an industrial cutter is used for grass-mowing. In this paper, we propose an explicit integration of a risk management process into the design of the software for an autonomous grass mower, with the aim of enhancing safety. Our approach is tested and validated in simulated scenarios that assess the effectiveness of different custom safety functionalities in terms of collision prevention, execution time, and the number of required human interventions. Full article
(This article belongs to the Special Issue Automation and Robots in Agriculture)
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