Robotics

22 pages, 14530 KiB

Open AccessArticle

Engineering of a Bio-Inspired Tiltable Oscillating Fin Submersible Thruster

by Zihao Liu and Duanling Li

Robotics 2024, 13(10), 154; https://doi.org/10.3390/robotics13100154 - 21 Oct 2024

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Oscillating fins are devices designed to produce thrust through periodic undulating movements. However, these structures lack flexibility and often provide thrust in only one fixed direction. Observation and biological references suggest that the dorsal fin rays of seahorses can tilt longitudinally in the [...] Read more.

Oscillating fins are devices designed to produce thrust through periodic undulating movements. However, these structures lack flexibility and often provide thrust in only one fixed direction. Observation and biological references suggest that the dorsal fin rays of seahorses can tilt longitudinally in the spine direction, changing the thrust direction. This study aims to analyze the dynamic effects of seahorse dorsal fin inclining and design a flexible bionic thruster based on this principle. Computational fluid dynamics analysis hypothesizes that fin inclination controls the net force direction in the vertical plane. A force sensor and pulley system test platform were constructed to examine the influences of wave features and the inclination angle on thrust in both vertical and horizontal directions, with discrete fin surfaces used to eliminate force interference. Force testing and snapshots indicate that wave velocity positively impacts net force magnitude, while fin inclination allows for control over force orientation. This tiltable oscillating fin thruster possesses more degrees of freedom, leading to better flexibility and providing controllable thrust orientation. Full article

(This article belongs to the Special Issue Bio-Inspired Service Robots)

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27 pages, 8843 KiB

Open AccessArticle

6-DOFs Robot Placement Based on the Multi-Criteria Procedure for Industrial Applications

by Francesco Aggogeri and Nicola Pellegrini

Robotics 2024, 13(10), 153; https://doi.org/10.3390/robotics13100153 - 16 Oct 2024

Viewed by 1203

Abstract

Robot acceptance is rapidly increasing in many different industrial applications. The advancement of production systems and machines requires addressing the productivity complexity and flexibility of current manufacturing processes in quasi-real time. Nowadays, robot placement is still achieved via industrial practices based on the [...] Read more.

Robot acceptance is rapidly increasing in many different industrial applications. The advancement of production systems and machines requires addressing the productivity complexity and flexibility of current manufacturing processes in quasi-real time. Nowadays, robot placement is still achieved via industrial practices based on the expertise of the workers and technicians, with the adoption of offline expensive software that demands time-consuming simulations, detailed time-and-motion mapping activities, and high competencies. Current challenges have been addressed mainly via path planning or robot-to-workpiece location optimization. Numerous solutions, from analytical to physical-based and data-driven formulation, have been discussed in the literature to solve these challenges. In this context, the machine learning approach has proven its superior performance. Nevertheless, the industrial environment is complex to model, generating extra training effort and making the learning procedure, in some cases, inefficient. The industrial problems concern workstation productivity; path-constrained minimal-time motions, considering the actuator’s torque limits; followed by robot vibration and the reduction in its accuracy and lifetime. This paper presents a procedure to find the robot base location for a prescribed task within the robot’s workspace, complying with multiple criteria. The proposed hybrid procedure includes analytical, physical-based, and data-driven modeling to solve the optimization problem. The contribution of the algorithm, for a given user-defined task, is the search for the best robot base location that enables the target points, maximizing the manipulability, avoiding singularities, and minimizing energy consumption. Firstly, the established method was verified using an anthropomorphic robot that considers different levels of a priori kinematics and system dynamics knowledge. The feasibility of the proposed method was evaluated through various simulations for small- and medium-sized robots. Then, a commercial offline program was compared, considering three scenarios and fourteen robots demonstrating an energy reduction in the 7.6–13.2% range. Moreover, the unknown joint dependency in real robot applications was investigated. From 11 robot positions for each active joint, a direct kinematic was appraised with an automatic DH scheme that generates the 3D workspace with an RMSE lower than 65.0 µm. Then, the inverse kinematic was computed using an ANN technique tuned with a genetic algorithm showing an RMSE in an S-shape task close to 702.0 µm. Finally, three experimental campaigns were performed with a set of tasks, repetitions, end-effector velocity, and payloads. The energy consumption reduction was observed in the 12.7–22.9% range. Consequently, the proposed procedure supports the reduction in workstation setup time and energy saving during industrial operations. Full article

(This article belongs to the Section Industrial Robots and Automation)

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26 pages, 7924 KiB

Open AccessArticle

Application of Barycentric Coordinates and the Jacobian Matrix to the Analysis of a Closed Structure Robot

by Ivan Chavdarov

Robotics 2024, 13(10), 152; https://doi.org/10.3390/robotics13100152 - 12 Oct 2024

Viewed by 878

Abstract

A new approach is presented to study the kinematic properties of stationary robots with a closed structure. It combines the application of conventional methods from kinematics with geometric parameters represented in a barycentric coordinate system. This allows examining the influence of the proportions [...] Read more.

A new approach is presented to study the kinematic properties of stationary robots with a closed structure. It combines the application of conventional methods from kinematics with geometric parameters represented in a barycentric coordinate system. This allows examining the influence of the proportions of the robot’s links on its basic mechanical characteristics. Each point from the newly introduced barycentric space corresponds to a set of robots with the same link proportions. The proposed approach is used to study three aspects: the link proportions for which the robot can exist; the shape of the robot’s workspace; and the possible singular configurations. This is valuable when evaluating the qualities of existing robots and could be applied to the design of new mechanical systems. An example of a 5-link robot with a closed structure is considered. The conditions for the existence of the mechanism and the conditions under which certain types of singular configurations can occur are defined. The example reveals the great potential of combining barycentric coordinates and Jacobian properties. The barycentric coordinates of 10 robots with a 5-link closed structure known from the literature are determined, and their properties are analyzed. The results are presented graphically. An extension of the application area of the approach is discussed. Full article

(This article belongs to the Section Intelligent Robots and Mechatronics)

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14 pages, 11980 KiB

Open AccessArticle

Suitable Method for Improving Friction Performance of Magnetic Wheels with Metal Yokes

by Masaru Tanida, Kosuke Ono, Takehiro Shiba and Yogo Takada

Robotics 2024, 13(10), 151; https://doi.org/10.3390/robotics13100151 - 11 Oct 2024

Viewed by 720

Abstract

A magnetic-wheeled robot is a type of robot that inspects large steel structures instead of humans, and it can run on a three-dimensional path by using wheels with built-in permanent magnets. For the robots to work safely, their magnetic wheels require both magnetic [...] Read more.

A magnetic-wheeled robot is a type of robot that inspects large steel structures instead of humans, and it can run on a three-dimensional path by using wheels with built-in permanent magnets. For the robots to work safely, their magnetic wheels require both magnetic attractive forces and friction forces. Planetary-geared magnetic wheels, which we have developed, make direct contact with their yokes on the running surface to ensure their magnetic attractive force. However, this design decreases their frictional performance more than common magnetic wheels covered with soft materials. Therefore, the yokes require methods that can improve their frictional performance without decreasing their attractive force. To consider the best method for the use of magnetic wheels, this study has run experiments with five types of yokes, which have different processing. As a result, the yokes with corroded surfaces could have maintained the attractive force more than 90% of the time and increased their traction forces by about 36% in static conditions and about 30% in dynamic conditions compared to yokes with no machining. The main reasons for these experimental results are that the rust layer has stable irregularities on the surface and includes ferromagnetic materials. Full article

(This article belongs to the Section Intelligent Robots and Mechatronics)

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20 pages, 2474 KiB

Open AccessArticle

A Numerical Integrator for Kinetostatic Folding of Protein Molecules Modeled as Robots with Hyper Degrees of Freedom

by Amal Kacem, Khalil Zbiss and Alireza Mohammadi

Robotics 2024, 13(10), 150; https://doi.org/10.3390/robotics13100150 - 2 Oct 2024

Viewed by 919

Abstract

The kinetostatic compliance method (KCM) models protein molecules as nanomechanisms consisting of numerous rigid peptide plane linkages. These linkages articulate with respect to each other through changes in the molecule dihedral angles, resulting in a kinematic mechanism with hyper degrees of freedom. Within [...] Read more.

The kinetostatic compliance method (KCM) models protein molecules as nanomechanisms consisting of numerous rigid peptide plane linkages. These linkages articulate with respect to each other through changes in the molecule dihedral angles, resulting in a kinematic mechanism with hyper degrees of freedom. Within the KCM framework, nonlinear interatomic forces drive protein folding by guiding the molecule’s dihedral angle vector towards its lowest energy state in a kinetostatic manner. This paper proposes a numerical integrator that is well suited to KCM-based protein folding and overcomes the limitations of traditional explicit Euler methods with fixed step size. Our proposed integration scheme is based on pseudo-transient continuation with an adaptive step size updating rule that can efficiently compute protein folding pathways, namely, the transient three-dimensional configurations of protein molecules during folding. Numerical simulations utilizing the KCM approach on protein backbones confirm the effectiveness of the proposed integrator. Full article

(This article belongs to the Special Issue Bioinspired Robotics: Toward Softer, Smarter and Safer)

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20 pages, 1298 KiB

Open AccessArticle

Structural–Parametric Synthesis of Path-Generating Mechanisms and Manipulators

by Zhumadil Baigunchekov, Med Amine Laribi, Giuseppe Carbone, Xuelin Wang, Qian Li, Dong Zhang, Rustem Kaiyrov, Zhadyra Zhumasheva and Birlik Sagitzhanov

Robotics 2024, 13(10), 149; https://doi.org/10.3390/robotics13100149 - 1 Oct 2024

Viewed by 760

Abstract

This paper presents a structural–parametric synthesis of the four-link and Stephenson I, Stephenson II, and Stephenson III six-link path-generating mechanisms. The four-link path-generating mechanism is formed by connecting the output point and the base using an active closing kinematic chain (CKC) with two [...] Read more.

This paper presents a structural–parametric synthesis of the four-link and Stephenson I, Stephenson II, and Stephenson III six-link path-generating mechanisms. The four-link path-generating mechanism is formed by connecting the output point and the base using an active closing kinematic chain (CKC) with two DOFs and a negative CKC of the type RR. The six-link path-generating mechanisms are formed by connecting the output point and the base by active, passive and negative CKCs. Active CKC has active kinematic pair, passive CKC has zero DOF, and negative CKC has a negative DOF. Active and negative CKCs impose geometrical constraints on the movement of the output point, and the geometric parameters of their links are determined by least-square approximation. Geometric parameters of the passive CKC are varied to satisfy the geometrical constraints of the active and negative CKCs. The CKCs of the active, passive and negative types, connecting the output point and the base, are the structural modules from which the different types of the path-generating mechanisms are synthesized. Numerical examples of the parametric synthesis of the four-link and six-link path-generating mechanisms are presented. Full article

(This article belongs to the Section Industrial Robots and Automation)

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13 pages, 2211 KiB

Open AccessArticle

Self-Localization of Anonymous UGVs Using Deep Learning from Periodic Aerial Images for a GPS-Denied Environment

by Olivier Poulet, Frédéric Guinand and François Guérin

Robotics 2024, 13(10), 148; https://doi.org/10.3390/robotics13100148 - 30 Sep 2024

Viewed by 886

Abstract

This work concerns the autonomous navigation of non-holonomic ground mobile robots in a GPS-denied environment. The objective was to locate, in a global frame, without GPS, anonymous ground mobile robots starting from two consecutive aerial images captured by a single fixed webcam. The [...] Read more.

This work concerns the autonomous navigation of non-holonomic ground mobile robots in a GPS-denied environment. The objective was to locate, in a global frame, without GPS, anonymous ground mobile robots starting from two consecutive aerial images captured by a single fixed webcam. The effectiveness of deep learning by a MultiLayer Perceptron in an indexed localization was compared to the methods studied in previous works. The ability of a robot to determine the position of other non-indexed robots was also performed. The structure and parameters of the network and the choice of the points taken into account during the learning phase to obtain a local optimum are presented. The results, obtained from simulated and experimental data, are compared to those obtained with more classical methods for different sampling periods (time between images). Full article

(This article belongs to the Topic Advances in Mobile Robotics Navigation, 2nd Volume)

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21 pages, 2711 KiB

Open AccessArticle

Increasing Horizontal Controlled Force Delivery Capabilities of Aerial Manipulators by Leveraging the Environment

by Santos Miguel Orozco Soto and Vincenzo Lippiello

Robotics 2024, 13(10), 147; https://doi.org/10.3390/robotics13100147 - 29 Sep 2024

Viewed by 695

Abstract

Delivering large horizontal controlled forces for long periods with aerial manipulators is not an easy task to accomplish; several factors including disturbances, reaction forces from the on-board arm or actuator’s limitations might diminish their horizontal force delivery capabilities. Aiming to mitigate these drawbacks, [...] Read more.

Delivering large horizontal controlled forces for long periods with aerial manipulators is not an easy task to accomplish; several factors including disturbances, reaction forces from the on-board arm or actuator’s limitations might diminish their horizontal force delivery capabilities. Aiming to mitigate these drawbacks, this paper presents a comprehensive study of the force delivery capabilities of aerial manipulators leveraging the environment. The methodology to evaluate the aforementioned capabilities is the Generalized-Jacobian-based force ellipsoid, which was applied to different types of both free-flying and attached-to-the-environment aerial manipulators. In addition, large controlled force delivery experiments with the mentioned manipulators were conducted on physics-engine-based robotics simulation software. The obtained results categorically demonstrate that aerial manipulators leveraging the environment are capable of delivering larger forces than their free-flying counterparts, which has not been proved in the literature so far in the field of aerial robotics. Full article

(This article belongs to the Section Aerospace Robotics and Autonomous Systems)

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16 pages, 4681 KiB

Open AccessArticle

RoboMan: An Adult-Sized Humanoid Robot with Enhanced Performance, Inherent Stability, and Two-Stage Balance Control to Facilitate Research on Humanoids

by Vahid Mohammadi, Mojtaba Hosseini, Farhad Jafari and Ahad Behboodi

Robotics 2024, 13(10), 146; https://doi.org/10.3390/robotics13100146 - 27 Sep 2024

Cited by 1 | Viewed by 1239

Abstract

Creating an adult-sized humanoid robot with stable walking capabilities is a major challenge in robotics. While many renowned research groups focus on robots for perilous work environments and precision tasks, our approach simplifies balance control, making it accessible to robotics research groups and [...] Read more.

Creating an adult-sized humanoid robot with stable walking capabilities is a major challenge in robotics. While many renowned research groups focus on robots for perilous work environments and precision tasks, our approach simplifies balance control, making it accessible to robotics research groups and educational institutes. This facilitates the development of complex functionalities such as vision and object manipulation for adult-sized humanoids. This research article introduces RoboMan II, an advanced version of RoboMan I, which won the most prestigious award in all humanoid robot leagues at RoboCup 2016 due to its exceptional performance in walking and playing soccer. RoboMan II features significant improvements in performance, inherent stability, recovery after falls, and balance control. To facilitate its development, RoboMan II is lighter and incorporates a modified foot and parallel structure for its leg to boost its inherent stability, along with a two-stage balance control system for Immediate Response and Gradual Adaptation, enhancing its adaptability in various environments. Our simulation results demonstrate that RoboMan II’s walking stability on flat surfaces improved significantly in the face of minor perturbations, with the number of steps within the stable region increasing from 24%, with only the immediate controller to 58% when both controllers were used. Similar improvements were observed on inclined surfaces. Additionally, the 3D CAD files for all of the robot parts are released as open source in conjunction with this paper to facilitate reproduction and further innovation. The forthcoming RoboMan III will incorporate custom servo motors for increased speed, torque, and enhanced fall recovery, preventing disengagement of the gear box after a fall. It promises to be an invaluable asset for research and practical applications in humanoid robotics. Full article

(This article belongs to the Section Humanoid and Human Robotics)

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18 pages, 3454 KiB

Open AccessArticle

Prescribed Time Interception of Moving Objects’ Trajectories Using Robot Manipulators

by Juan Alejandro Flores-Campos, Christopher René Torres-San-Miguel, Juan Carlos Paredes-Rojas and Adolfo Perrusquía

Robotics 2024, 13(10), 145; https://doi.org/10.3390/robotics13100145 - 27 Sep 2024

Viewed by 669

Abstract

Trajectory interception is a critical synchronization element in the transportation and manufacturing sectors using robotic platforms. This is usually performed by matching the position and velocity of a target object with the position and velocity of the robot interceptor. However, the synchronization task [...] Read more.

Trajectory interception is a critical synchronization element in the transportation and manufacturing sectors using robotic platforms. This is usually performed by matching the position and velocity of a target object with the position and velocity of the robot interceptor. However, the synchronization task is exasperated by (i) the proper gain tuning of the controller, (ii) the dynamic response of the robotic platform, (iii) the velocity constraints in the actuators, and (iv) the trajectory profile exhibited by the moving object. This means that the interception time is not controlled, which is critical for energy optimization, resources, and production. This paper proposes a prescribed time trajectory interception algorithm for robot manipulators. The approach uses the finite-time convergence properties of sliding mode control combined with a terminal attractor based on a time base generator. The combined approach guarantees trajectory interception in a prescribed time with robust properties. Simulation studies are conducted using the first three degrees of freedom (DOFs) of a RV-M1 robot under single- and multi-object interception tasks. The results verify the effectiveness of the proposed methodology under different hyperparameter configurations. Full article

(This article belongs to the Special Issue Adaptive and Nonlinear Control of Robotics)

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21 pages, 2181 KiB

Open AccessArticle

Influence of Social Identity and Personality Traits in Human–Robot Interactions

by Mariacarla Staffa, Lorenzo D’Errico and Antonio Maratea

Robotics 2024, 13(10), 144; https://doi.org/10.3390/robotics13100144 - 27 Sep 2024

Viewed by 1038

Abstract

This study explores the role of social identity in human–robot interactions, focusing on a scenario where a humanoid robot functions as a bartender with either a positive or negative personality. Conducted with 28 participants, the experiment utilized the Big-5 questionnaire to assess personality [...] Read more.

This study explores the role of social identity in human–robot interactions, focusing on a scenario where a humanoid robot functions as a bartender with either a positive or negative personality. Conducted with 28 participants, the experiment utilized the Big-5 questionnaire to assess personality traits and the Godspeed questionnaire to gauge perceptions of the robot. The research sought to determine if users could perceive the robot’s distinct identities and if these perceptions were influenced by the participants’ personality traits. The findings indicated that participants could effectively discern the robot’s different personalities, validating the potential for programming robots to convey specific social identities. Despite the limited sample size, the results suggest that participants’ initial emotional states and personality traits significantly influenced their perceptions, suggesting that customizing a robot’s identity to match the interlocutor’s personality can enhance the interaction experience. As a preliminary investigation, this study contributes valuable insights into human–robot interaction dynamics and lays the groundwork for future research in the development of socially integrated robotic systems. Full article

(This article belongs to the Special Issue Social Robots for the Human Well-Being)

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18 pages, 17808 KiB

Open AccessArticle

Virtual Hand Deformation-Based Pseudo-Haptic Feedback for Enhanced Force Perception and Task Performance in Physically Constrained Teleoperation

by Kento Yamamoto, Yaonan Zhu, Tadayoshi Aoyama and Yasuhisa Hasegawa

Robotics 2024, 13(10), 143; https://doi.org/10.3390/robotics13100143 - 24 Sep 2024

Viewed by 1493

Abstract

Force-feedback devices enhance task performance in most robot teleoperations. However, their increased size with additional degrees of freedom can limit the robot’s applicability. To address this, an interface that visually presents force feedback is proposed, eliminating the need for bulky physical devices. Our [...] Read more.

Force-feedback devices enhance task performance in most robot teleoperations. However, their increased size with additional degrees of freedom can limit the robot’s applicability. To address this, an interface that visually presents force feedback is proposed, eliminating the need for bulky physical devices. Our telepresence system renders robotic hands transparent in the camera image while displaying virtual hands. The forces applied to the robot deform these virtual hands. The deformation creates an illusion that the operator’s hands are deforming, thus providing pseudo-haptic feedback. We conducted a weight comparison experiment in a virtual reality environment to evaluate force sensitivity. In addition, we conducted an object touch experiment to assess the speed of contact detection in a robot teleoperation setting. The results demonstrate that our method significantly surpasses conventional pseudo-haptic feedback in conveying force differences. Operators detected object touch 24.7% faster using virtual hand deformation compared to conditions without feedback. This matches the response times of physical force-feedback devices. This interface not only increases the operator’s force sensitivity but also matches the performance of conventional force-feedback devices without physically constraining the operator. Therefore, the interface enhances both task performance and the experience of teleoperation. Full article

(This article belongs to the Special Issue Extended Reality and AI Empowered Robots)

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Graphical abstract

26 pages, 10321 KiB

Open AccessArticle

Control of a Hexapod Robot Considering Terrain Interaction

by Stefano Arrigoni, Marco Zangrandi, Giovanni Bianchi and Francesco Braghin

Robotics 2024, 13(10), 142; https://doi.org/10.3390/robotics13100142 - 24 Sep 2024

Viewed by 1081

Abstract

Bioinspired walking hexapod robots are a relatively young branch of robotics. Despite the high degree of flexibility and adaptability derived from their redundant design, open-source implementations do not fully utilize this potential. This paper proposes an exhaustive description of a hexapod robot-specific control [...] Read more.

Bioinspired walking hexapod robots are a relatively young branch of robotics. Despite the high degree of flexibility and adaptability derived from their redundant design, open-source implementations do not fully utilize this potential. This paper proposes an exhaustive description of a hexapod robot-specific control architecture based on open-source code that allows for complete control over a robot’s speed, body orientation, and walk gait type. Furthermore, terrain interaction is deeply investigated, leading to the development of a terrain-adapting control algorithm that allows the robot to react swiftly to the terrain shape and asperities, such as non-linearities and non-continuity within the workspace. For this purpose, a dynamic model derived from interpreting the hexapod movement is presented and validated through a Matlab SimMechanics^TM simulation. Furthermore, a feedback control system is developed, which is able to recognize leg–terrain touch and react accordingly to ensure movement stability. Finally, the results from an experimental campaign based on the PhantomX AX Metal Hexapod Mark II robotic platform by Trossen Robotics^TM are reported. Full article

(This article belongs to the Special Issue Legged Robots into the Real World, 2nd Edition)

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29 pages, 5331 KiB

Open AccessArticle

Enhanced Particle Swarm Optimisation for Multi-Robot Path Planning with Bezier Curve Smoothing

by Yi-Ler Poy, Zhi-Yu Loke, Shalini Darmaraju, Choon-Hian Goh, Ban-Hoe Kwan, Haipeng Liu and Danny Wee Kiat Ng

Robotics 2024, 13(10), 141; https://doi.org/10.3390/robotics13100141 - 24 Sep 2024

Viewed by 982

Abstract

This paper presents an Enhanced Particle Swarm Optimisation (EPSO) algorithm to improve multi-robot path planning by integrating a new path planning scheme with a cubic Bezier curve trajectory smoothing algorithm. Traditional PSO algorithms often result in suboptimal paths with numerous turns, necessitating frequent [...] Read more.

This paper presents an Enhanced Particle Swarm Optimisation (EPSO) algorithm to improve multi-robot path planning by integrating a new path planning scheme with a cubic Bezier curve trajectory smoothing algorithm. Traditional PSO algorithms often result in suboptimal paths with numerous turns, necessitating frequent stops and higher energy consumption. The proposed EPSO algorithm addresses these issues by generating smoother paths that reduce the number of turns and enhance the efficiency of multi-robot systems. The proposed algorithm was evaluated through simulations in two scenarios, and its performance was compared against the basic PSO algorithm. The results demonstrated that EPSO consistently produced shorter, smoother paths with fewer directional changes, albeit with slightly longer execution times. This improvement translates to more efficient navigation, reduced energy consumption, and enhanced overall performance of multi-robot systems. The findings underscore the potential of EPSO in applications requiring precise and efficient path planning, highlighting its contribution to advancing the field of robotics. Full article

(This article belongs to the Section AI in Robotics)

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Robotics, Volume 13, Issue 10 (October 2024) – 14 articles

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