Robotics

16 pages, 1659 KiB

Open AccessArticle

Experimental Validation of Passive Monopedal Hopping Mechanism

by Jun-ya Nagase, Takuya Kawase and Syunya Ueno

Robotics 2025, 14(2), 18; https://doi.org/10.3390/robotics14020018 (registering DOI) - 3 Feb 2025

Passive dynamic locomotion, which relies solely on the interaction between the body and the environment, is being explored as an energy-efficient method of movement. The authors’ laboratory investigates passive hopping mechanisms that do not require actuators or sensors. In previous studies, it was [...] Read more.

Passive dynamic locomotion, which relies solely on the interaction between the body and the environment, is being explored as an energy-efficient method of movement. The authors’ laboratory investigates passive hopping mechanisms that do not require actuators or sensors. In previous studies, it was demonstrated that an asymptotically stable limit cycle exists in the leg dynamics of a passive hopping model with constrained torso posture. In this study, a monopedal passive hopping robot with constrained torso posture was constructed to validate the existence of the limit cycle. The leg dynamics were evaluated by comparing the trajectories of the model and robot. The results revealed that the leg dynamics of the simulation model represent those of the physical robot. Furthermore, robustness to step disturbances confirmed the validity of leg dynamics. Full article

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

21 pages, 1889 KiB

Open AccessArticle

Simultaneous Path Planning and Task Allocation in Dynamic Environments

by Jennifer David and Rafael Valencia

Robotics 2025, 14(2), 17; https://doi.org/10.3390/robotics14020017 - 1 Feb 2025

Viewed by 141

Abstract

This paper addresses the challenge of coordinating task allocation and generating collision-free trajectories for a fleet of mobile robots in dynamic environments. Our approach introduces an integrated framework comprising a centralized task allocation system and a distributed trajectory planner. The centralized task allocation [...] Read more.

This paper addresses the challenge of coordinating task allocation and generating collision-free trajectories for a fleet of mobile robots in dynamic environments. Our approach introduces an integrated framework comprising a centralized task allocation system and a distributed trajectory planner. The centralized task allocation system, employing a heuristic approach, aims to minimize the maximum spatial cost among the slowest robots. Tasks and trajectories are continuously refined using a distributed version of CHOMP (Covariant Hamiltonian Optimization for Motion Planning), tailored for multiple-wheeled mobile robots where the spatial costs are derived from a high-level global path planner. By employing this combined methodology, we are able to achieve near-optimal solutions and collision-free trajectories with computational performance for up to 50 robots within seconds. Full article

(This article belongs to the Special Issue Autonomous Navigation of Mobile Robots in Unstructured Environments)

17 pages, 10027 KiB

Open AccessArticle

Assembly Modes and Workspace Analysis of a 3-RRR Planar Manipulator

by Florentin Buium, Ioan Doroftei and Stelian Alaci

Robotics 2025, 14(2), 16; https://doi.org/10.3390/robotics14020016 - 31 Jan 2025

Viewed by 169

Abstract

This paper examines the influence of the eight assembling modes of the 3-RRR planar manipulator on its workspace. The workspace is analyzed considering both first-type and second-type singularities. Understanding these issues is crucial in the process of designing such manipulators to avoid unfavorable [...] Read more.

This paper examines the influence of the eight assembling modes of the 3-RRR planar manipulator on its workspace. The workspace is analyzed considering both first-type and second-type singularities. Understanding these issues is crucial in the process of designing such manipulators to avoid unfavorable cases. Additionally, a modular platform concept, suitable for experimental testing and informed by the numerical results presented here, is proposed. The outcomes of the experimental tests will be addressed in future work. Full article

(This article belongs to the Special Issue Selected Papers from MEDER 2024: Advances in Mechanism Design for Robotics)

22 pages, 7750 KiB

Open AccessArticle

Haptic Guidance System for Teleoperation Based on Trajectory Similarity

by Hikaru Nagano, Tomoki Nishino, Yuichi Tazaki and Yasuyoshi Yokokohji

Robotics 2025, 14(2), 15; https://doi.org/10.3390/robotics14020015 - 30 Jan 2025

Viewed by 221

Abstract

Teleoperation technology enables remote control of machines, but often requires complex manoeuvres that pose significant challenges for operators. To mitigate these challenges, assistive systems have been developed to support teleoperation. This study presents a teleoperation guidance system that provides assistive force feedback to [...] Read more.

Teleoperation technology enables remote control of machines, but often requires complex manoeuvres that pose significant challenges for operators. To mitigate these challenges, assistive systems have been developed to support teleoperation. This study presents a teleoperation guidance system that provides assistive force feedback to help operators align more accurately with desired trajectories. Two key issues remain: (1) the lack of a flexible, real-time approach to defining desired trajectories and calculating assistive forces, and (2) uncertainty about the effects of forward motion assistance within the assistive forces. To address these issues, we propose a novel approach that captures the posture trajectory of the local control interface, statistically generates a reference trajectory, and incorporates forward motion as an adjustable parameter. In Experiment 1, which involved simulating an object transfer task, the proposed method significantly reduced the operator’s workload compared to conventional techniques, especially in dynamic target scenarios. Experiment 2, which involved more complex paths, showed that assistive forces with　forward assistance significantly improved manoeuvring performance. Full article

(This article belongs to the Special Issue Robot Teleoperation Integrating with Augmented Reality)

31 pages, 1489 KiB

Open AccessArticle

Quantum-Inspired Sliding-Mode Control to Enhance the Precision and Energy Efficiency of an Articulated Industrial Robotic Arm

by Mehdi Fazilat and Nadjet Zioui

Robotics 2025, 14(2), 14; https://doi.org/10.3390/robotics14020014 - 29 Jan 2025

Viewed by 313

Abstract

Maintaining precise and robust control in robotic systems, particularly those with nonlinear dynamics and external disturbances, is a significant challenge in robotics. Sliding-mode control (SMC) is a widely used technique to tackle these issues; however, it is plagued by chattering and computational complexity, [...] Read more.

Maintaining precise and robust control in robotic systems, particularly those with nonlinear dynamics and external disturbances, is a significant challenge in robotics. Sliding-mode control (SMC) is a widely used technique to tackle these issues; however, it is plagued by chattering and computational complexity, which limit its effectiveness in high-precision environments. This study aims to develop and assess a quantum-inspired sliding-mode control (QSMC) strategy to enhance the SMC’s robustness, precision, and computational efficiency, specifically in controlling a six-jointed articulated robotic arm. The methodology involves creating a comprehensive kinematic and dynamic model of the robot, followed by implementing both classic SMC and the proposed Q-SMC in a comparative way. The simulation results confirm that the Q-SMC method outperforms the classic SMC, particularly in reducing chattering, improving tracking accuracy, and decreasing energy consumption by approximately 3.79%. These findings suggest that the Q-SMC technique provides a promising alternative to classical control methods, with potential applications in tasks requiring high precision and efficient robotic manipulations. Full article

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

17 pages, 3461 KiB

Open AccessArticle

Real-Time Registration of 3D Underwater Sonar Scans

by António Ferreira, José Almeida, Aníbal Matos and Eduardo Silva

Robotics 2025, 14(2), 13; https://doi.org/10.3390/robotics14020013 - 29 Jan 2025

Viewed by 272

Abstract

Due to space and energy restrictions, lightweight autonomous underwater vehicles (AUVs) are usually fitted with low-power processing units, which limits the ability to run demanding applications in real time during the mission. However, several robotic perception tasks reveal a parallel nature, where the [...] Read more.

Due to space and energy restrictions, lightweight autonomous underwater vehicles (AUVs) are usually fitted with low-power processing units, which limits the ability to run demanding applications in real time during the mission. However, several robotic perception tasks reveal a parallel nature, where the same processing routine is applied for multiple independent inputs. In such cases, leveraging parallel execution by offloading tasks to a GPU can greatly enhance processing speed. This article presents a collection of generic matrix manipulation kernels, which can be combined to develop parallelized perception applications. Taking advantage of those building blocks, we report a parallel implementation for the 3DupIC algorithm—a probabilistic scan matching method for sonar scan registration. Tests demonstrate the algorithm’s real-time performance, enabling 3D sonar scan matching to be executed in real time onboard the EVA AUV. Full article

(This article belongs to the Special Issue Localization and 3D Mapping of Intelligent Robotics)

21 pages, 10181 KiB

Open AccessArticle

Development of a Rehabilitation Apparatus for Frozen Shoulder Enabling Total Motion of Shoulder Complex

by Xiao Sun, Koji Makino, Daichi Kurita, Hiromi Kaneko, Kazuyoshi Ishida and Hidetsugu Terada

Robotics 2025, 14(2), 12; https://doi.org/10.3390/robotics14020012 - 29 Jan 2025

Viewed by 281

Abstract

This article describes an apparatus developed by the authors as a substitution for physical therapists regarding mechanical movements in the rehabilitation of frozen shoulder. In particular, the performance of this apparatus is improved in comparison with existing methods in terms of the following [...] Read more.

This article describes an apparatus developed by the authors as a substitution for physical therapists regarding mechanical movements in the rehabilitation of frozen shoulder. In particular, the performance of this apparatus is improved in comparison with existing methods in terms of the following two major points: (1) realization of individual rehabilitation for the patient’s scapula by an innovative parallel–serial hybrid linkage design and supporting parts that can fix and move the patient’s scapula; and (2) the addition of a “teaching” and “playback” mode to enable the apparatus to record the motion of rehabilitation, allowing it to be customized for each patient by physical therapists and reproduce the recorded motion accurately, thus freeing physical therapists from repetitive rehabilitation routines. With the introduction of the whole system, experimental results are shown and discussed to verify and evaluate the performance of the developed apparatus. Full article

(This article belongs to the Special Issue Selected Papers from MEDER 2024: Advances in Mechanism Design for Robotics)

19 pages, 3390 KiB

Open AccessArticle

Tension-Aware Motion Planning for Tethered Robots

by Rogério R. Lima and Guilherme A. S. Pereira

Robotics 2025, 14(2), 11; https://doi.org/10.3390/robotics14020011 - 28 Jan 2025

Viewed by 287

Abstract

This paper presents a path-planning approach for tethered robots. The proposed planner finds paths that minimize the tether tension due to tether–obstacle and tether–floor interaction. The method assumes that the tether is managed externally by a tether management system and pulled by the [...] Read more.

This paper presents a path-planning approach for tethered robots. The proposed planner finds paths that minimize the tether tension due to tether–obstacle and tether–floor interaction. The method assumes that the tether is managed externally by a tether management system and pulled by the robot. The planner is initially formulated for ground robots in a 2D environment and then extended for 3D scenarios, where it can be applied to tethered aerial and underwater vehicles. The proposed approach assumes a taut tether between two consecutive contact points and knowledge of the coefficient of friction of the obstacles present in the environment. The method first computes the visibility graph of the environment, in which each node represents a vertex of an obstacle. Then, a second graph, named the tension-aware graph, is built so that the tether–environment interaction, formulated in terms of tension, is computed and used as the cost of the edges. A graph search algorithm (e.g., Dijkstra) is then used to compute a path with minimum tension, which can help the tethered robot reach longer distances by minimizing the tension required to drag the tether along the way. This paper presents simulations and a real-world experiment that illustrate the characteristics of the method. Full article

(This article belongs to the Special Issue Autonomous Robotics for Exploration)

27 pages, 12074 KiB

Open AccessArticle

Near Time-Optimal Trajectories with ISO Standard Constraints for Human–Robot Collaboration in Fabric Co-Transportation

by Renat Kermenov, Alessandro Di Biase, Ilaria Pellicani, Sauro Longhi and Andrea Bonci

Robotics 2025, 14(2), 10; https://doi.org/10.3390/robotics14020010 - 27 Jan 2025

Viewed by 448

Abstract

Enabling robots to work safely close to humans requires both adherence to safety standards and the development of appropriate strategies to plan and control robot movements in accordance with human movements. Collaboration between humans and robots in a shared environment is a joint [...] Read more.

Enabling robots to work safely close to humans requires both adherence to safety standards and the development of appropriate strategies to plan and control robot movements in accordance with human movements. Collaboration between humans and robots in a shared environment is a joint activity aimed at completing specific tasks, requiring coordination, synchronisation, and sometimes physical contact, in which each party contributes its own skills and resources. Among the most challenging tasks of human–robot cooperation is the co-transport of deformable materials such as fabrics. This paper proposes a method for generating the trajectory of a collaborative manipulator. The method is designed for the co-transport of materials such as fabrics. It combines a near time-optimal control strategy that ensures responsiveness in following human actions while simultaneously guaranteeing compliance with the safety limits imposed by current regulations. The combination of these two elements results in a viable co-transport solution which preserves the safety of human operators. This is achieved by constraining the path of the robot trajectory with prescribed velocities and accelerations while simultaneously ensuring a near time-optimal control strategy. In short, the robot movement is generated in such a way as to ensure both the tracking of humans in the co-transportation task and compliance with safety limits. As a first attempt to adopt the proposed approach to integrate time-optimal strategies into human–robot interaction, the simulations and preliminary experimental result obtained are promising. Full article

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

► Show Figures

Figure 1

26 pages, 656 KiB

Open AccessReview

Agricultural Robotics: A Technical Review Addressing Challenges in Sustainable Crop Production

by Maria Spagnuolo, Giuseppe Todde, Maria Caria, Nicola Furnitto, Giampaolo Schillaci and Sabina I. G. Failla

Robotics 2025, 14(2), 9; https://doi.org/10.3390/robotics14020009 - 23 Jan 2025

Viewed by 466

Abstract

The adoption of agricultural robots is revolutionizing the agricultural sector, offering innovative solutions to optimize production and reduce environmental impact. This review examines the main functions and applications of agricultural robots, with a focus on the crops handled and the technologies employed. The [...] Read more.

The adoption of agricultural robots is revolutionizing the agricultural sector, offering innovative solutions to optimize production and reduce environmental impact. This review examines the main functions and applications of agricultural robots, with a focus on the crops handled and the technologies employed. The study analyzes the current state of the art regarding the market trend of agricultural robots used in field and greenhouse operations. Several solutions are emerging, some already implemented and others still in the prototype or project stage. These solutions are beginning to spread, though they may still seem far from widespread field application, particularly given the peculiarities and heterogeneity of the global agricultural landscape. In the face of the many benefits associated with the use of agricultural robots, even today some technical bottlenecks and costs limit their widespread use by farmers. The review provides a fairly comprehensive and up-to-date overview of current trends in agricultural automation, suggesting new areas of research to improve the efficiency and adaptability of robotic systems to different types of crops and environments. Full article

(This article belongs to the Section Agricultural and Field Robotics)

27 pages, 4409 KiB

Open AccessArticle

Design of a Novel Bio-Inspired Three Degrees of Freedom (3DOF) Spherical Robotic Manipulator and Its Application in Human–Robot Interactions

by Suleyman Soltanov and Rodney Roberts

Robotics 2025, 14(2), 8; https://doi.org/10.3390/robotics14020008 - 22 Jan 2025

Viewed by 1006

Abstract

Studying the interactions between biological organisms and their environment provides engineers with valuable insights for developing complex mechanical systems and fostering the creation of novel technological innovations. In this study, we introduce a novel bio-inspired three degrees of freedom (DOF) spherical robotic manipulator [...] Read more.

Studying the interactions between biological organisms and their environment provides engineers with valuable insights for developing complex mechanical systems and fostering the creation of novel technological innovations. In this study, we introduce a novel bio-inspired three degrees of freedom (DOF) spherical robotic manipulator (SRM), designed to emulate the biomechanical properties observed in nature. The design utilizes the transformation of spherical Complex Spatial Kinematic Pairs (CSKPs) to synthesize bio-inspired robotic manipulators. Additionally, the use of screw theory and the Levenberg–Marquardt algorithm for kinematic parameter computation supports further advancements in human–robot interactions and simplifies control processes. The platform directly transmits motion from the motors to replicate the ball-and-socket mobility of biological joints, minimizing mechanical losses, and optimizing energy efficiency for superior spatial mobility. The proposed 3DOF SRM provides advantages including an expanded workspace, enhanced dexterity, and a lightweight, compact design. Experimental validation, conducted through SolidWorks, MATLAB, Python, and Arduino, demonstrates the versatility and broad application potential of the novel bio-inspired 3DOF SRM, positioning it as a robust solution for a wide range of robotic applications. Full article

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

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Robotics, Volume 14, Issue 2 (February 2025) – 11 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI