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Robotics, Volume 12, Issue 4 (August 2023) – 29 articles

Cover Story (view full-size image): This paper considers the problem of making a safe compliant contact between a human and an assistive robot during Physical Human–Robot Interaction (PHRI). Specifically, we propose a hybrid force/velocity/attitude control for a PHRI system based on measurements from a wrist-mounted six-axis force/torque sensor. While automatically aligning the end-effector surface with the unknown environmental (human) surface, a desired force is applied in the normal direction while following desired velocity commands in the tangential directions. A Lyapunov-based stability analysis is provided to prove the convergence/passivity of the interaction to ensure performance and safety. Experimental results, using a kinematically redundant robotic manipulator, verify the performance and robustness of the proposed controller in the presence of dynamic uncertainties. View this paper
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18 pages, 1711 KiB  
Article
MURM: Utilization of Multi-Views for Goal-Conditioned Reinforcement Learning in Robotic Manipulation
by Seongwon Jang, Hyemi Jeong and Hyunseok Yang
Robotics 2023, 12(4), 119; https://doi.org/10.3390/robotics12040119 - 19 Aug 2023
Viewed by 1359
Abstract
We present a novel framework, multi-view unified reinforcement learning for robotic manipulation (MURM), which efficiently utilizes multiple camera views to train a goal-conditioned policy for a robot to perform complex tasks. The MURM framework consists of three main phases: (i) demo collection from [...] Read more.
We present a novel framework, multi-view unified reinforcement learning for robotic manipulation (MURM), which efficiently utilizes multiple camera views to train a goal-conditioned policy for a robot to perform complex tasks. The MURM framework consists of three main phases: (i) demo collection from an expert, (ii) representation learning, and (iii) offline reinforcement learning. In the demo collection phase, we design a scripted expert policy that uses privileged information, such as Cartesian coordinates of a target and goal, to solve the tasks. We add noise to the expert policy to provide sufficient interactive information about the environment, as well as suboptimal behavioral trajectories. We designed three tasks in a Pybullet simulation environment, including placing an object in a desired goal position and picking up various objects that are randomly positioned in the environment. In the representation learning phase, we use a vector-quantized variational autoencoder (VQVAE) to learn a more structured latent representation that makes it feasible to train for RL compared to high-dimensional raw images. We train VQVAE models for each distinct camera view and define the best viewpoint settings for training. In the offline reinforcement learning phase, we use the Implicit Q-learning (IQL) algorithm as our baseline and introduce a separated Q-functions method and dropout method that can be implemented in multi-view settings to train the goal-conditioned policy with supervised goal images. We conduct experiments in simulation and show that the single-view baseline fails to solve complex tasks, whereas MURM is successful. Full article
(This article belongs to the Section AI in Robotics)
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15 pages, 2750 KiB  
Article
Online Motion Planning for Safe Human–Robot Cooperation Using B-Splines and Hidden Markov Models
by Giovanni Braglia, Matteo Tagliavini, Fabio Pini and Luigi Biagiotti
Robotics 2023, 12(4), 118; https://doi.org/10.3390/robotics12040118 - 18 Aug 2023
Cited by 1 | Viewed by 1296
Abstract
When humans and robots work together, ensuring safe cooperation must be a priority. This research aims to develop a novel real-time planning algorithm that can handle unpredictable human movements by both slowing down task execution and modifying the robot’s path based on the [...] Read more.
When humans and robots work together, ensuring safe cooperation must be a priority. This research aims to develop a novel real-time planning algorithm that can handle unpredictable human movements by both slowing down task execution and modifying the robot’s path based on the proximity of the human operator. To achieve this, an efficient method for updating the robot’s motion is developed using a two-fold control approach that combines B-splines and hidden Markov models. This allows the algorithm to adapt to a changing environment and avoid collisions. The proposed framework is thus validated using the Franka Emika Panda robot in a simple start–goal task. Our algorithm successfully avoids collision with the moving hand of an operator monitored by a fixed camera. Full article
(This article belongs to the Special Issue Motion Trajectory Prediction for Mobile Robots)
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28 pages, 3371 KiB  
Review
Tethered Unmanned Aerial Vehicles—A Systematic Review
by Miguel Nakajima Marques, Sandro Augusto Magalhães, Filipe Neves Dos Santos and Hélio Sousa Mendonça
Robotics 2023, 12(4), 117; https://doi.org/10.3390/robotics12040117 - 14 Aug 2023
Cited by 2 | Viewed by 3564
Abstract
In recent years, there has been a remarkable surge in the development and research of tethered aerial systems, thus reflecting a growing interest in their diverse applications. Long-term missions involving aerial vehicles present significant challenges due to the limitations of current battery solutions. [...] Read more.
In recent years, there has been a remarkable surge in the development and research of tethered aerial systems, thus reflecting a growing interest in their diverse applications. Long-term missions involving aerial vehicles present significant challenges due to the limitations of current battery solutions. Tethered vehicles can circumvent such restrictions by receiving their power from an element on the ground such as a ground station or a mobile terrestrial platform. Tethered Unmanned Aerial Vehicles (UAVs) can also be applied to load transportation achieved by a single or multiple UAVs. This paper presents a comprehensive systematic literature review, with a special focus on solutions published in the last five years (2017–2022). It emphasizes the key characteristics that are capable of grouping publications by application scope, propulsion method, energy transfer solution, perception sensors, and control techniques adopted. The search was performed in six different databases, thereby resulting in 1172 unique publications, from which 182 were considered for inclusion in the data extraction phase of this review. Among the various aircraft types, multirotors emerged as the most widely used category. We also identified significant variations in the application scope of tethered UAVs, thus leading to tailored approaches for each use case, such as the fixed-wing model being predominant in the wind generation application and the lighter-than-air aircraft in the meteorology field. Notably, the classical Proportional–Integral–Derivative (PID) control scheme emerged as the predominant control methodology across the surveyed publications. Regarding energy transfer techniques, most publications did not explicitly describe their approach. However, among those that did, high-voltage DC energy transfer emerged as the preferred solution. In summary, this systematic literature review provides valuable insights into the current state of tethered aerial systems, thereby showcasing their potential as a robust and sustainable alternative to address the challenges associated with long-duration aerial missions and load transportation. Full article
(This article belongs to the Special Issue UAV Systems and Swarm Robotics)
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26 pages, 5199 KiB  
Article
A Passivity-Based Framework for Safe Physical Human–Robot Interaction
by Zhangchi Ding, Masoud Baghbahari and Aman Behal
Robotics 2023, 12(4), 116; https://doi.org/10.3390/robotics12040116 - 14 Aug 2023
Viewed by 1100
Abstract
In this paper, the problem of making a safe compliant contact between a human and an assistive robot is considered. Users with disabilities have a need to utilize their assistive robots for physical human–robot interaction (PHRI) during certain activities of daily living (ADLs). [...] Read more.
In this paper, the problem of making a safe compliant contact between a human and an assistive robot is considered. Users with disabilities have a need to utilize their assistive robots for physical human–robot interaction (PHRI) during certain activities of daily living (ADLs). Specifically, we propose a hybrid force/velocity/attitude control for a PHRI system based on measurements from a six-axis force/torque sensor mounted on the robot wrist. While automatically aligning the end-effector surface with the unknown environmental (human) surface, a desired commanded force is applied in the normal direction while following desired velocity commands in the tangential directions. A Lyapunov-based stability analysis is provided to prove both the convergence as well as passivity of the interaction to ensure both performance and safety. Simulation as well as experimental results verify the performance and robustness of the proposed hybrid controller in the presence of dynamic uncertainties as well as safe physical human–robot interactions for a kinematically redundant robotic manipulator. Full article
(This article belongs to the Section Humanoid and Human Robotics)
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25 pages, 9300 KiB  
Article
Design of Bluetooth 5.1 Angle of Arrival Homing Controller for Autonomous Mobile Robot
by Katrina Weinmann and Steve Simske
Robotics 2023, 12(4), 115; https://doi.org/10.3390/robotics12040115 - 11 Aug 2023
Cited by 2 | Viewed by 1692
Abstract
With the improvement of autonomous robot navigation technologies, mobile robots can now be deployed in uncertain, real-world environments. An aspect of autonomous robot navigation in such scenarios is the capability to navigate to a real-time determined (previously unknown) location anywhere in its vicinity. [...] Read more.
With the improvement of autonomous robot navigation technologies, mobile robots can now be deployed in uncertain, real-world environments. An aspect of autonomous robot navigation in such scenarios is the capability to navigate to a real-time determined (previously unknown) location anywhere in its vicinity. This is especially pertinent for indoor navigation where existing localization technologies such as GPS do not provide sufficient accuracy of target location. In this paper, a controller design is proposed which homes a mobile robot to an object of unknown location using Bluetooth 5.1 Angle of Arrival (AoA) technology. The proposed setup consists of a target object with a Bluetooth beacon and a single Bluetooth antenna array mounted on a mobile robot. The controller uses a hybrid approach to calculating and updating the estimated target position by implementing parallax and vector position calculations from AoA and RSSI Bluetooth data. Simulations with various levels of sensor noise showed convergence to accurate target positions (mean accuracy of 0.12 m or less) in both obstacle-free and obstacle-present environments. The controller can be implemented as a standalone controller by directly commanding robot motion toward the target, or it can integrate with other existing robot navigation techniques by outputting a target position. Full article
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18 pages, 5020 KiB  
Article
SceneGATE: Scene-Graph Based Co-Attention Networks for Text Visual Question Answering
by Feiqi Cao, Siwen Luo, Felipe Nunez, Zean Wen, Josiah Poon and Soyeon Caren Han
Robotics 2023, 12(4), 114; https://doi.org/10.3390/robotics12040114 - 07 Aug 2023
Cited by 1 | Viewed by 1547
Abstract
Visual Question Answering (VQA) models fail catastrophically on questions related to the reading of text-carrying images. However, TextVQA aims to answer questions by understanding the scene texts in an image–question context, such as the brand name of a product or the time on [...] Read more.
Visual Question Answering (VQA) models fail catastrophically on questions related to the reading of text-carrying images. However, TextVQA aims to answer questions by understanding the scene texts in an image–question context, such as the brand name of a product or the time on a clock from an image. Most TextVQA approaches focus on objects and scene text detection, which are then integrated with the words in a question by a simple transformer encoder. The focus of these approaches is to use shared weights during the training of a multi-modal dataset, but it fails to capture the semantic relations between an image and a question. In this paper, we proposed a Scene Graph-Based Co-Attention Network (SceneGATE) for TextVQA, which reveals the semantic relations among the objects, the Optical Character Recognition (OCR) tokens and the question words. It is achieved by a TextVQA-based scene graph that discovers the underlying semantics of an image. We create a guided-attention module to capture the intra-modal interplay between the language and the vision as a guidance for inter-modal interactions. To permit explicit teaching of the relations between the two modalities, we propose and integrate two attention modules, namely a scene graph-based semantic relation-aware attention and a positional relation-aware attention. We conduct extensive experiments on two widely used benchmark datasets, Text-VQA and ST-VQA. It is shown that our SceneGATE method outperforms existing ones because of the scene graph and its attention modules. Full article
(This article belongs to the Special Issue Chatbots and Talking Robots)
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22 pages, 16544 KiB  
Article
Application of Path Planning for a Mobile Robot Assistance System Based on OpenStreetMap Data
by Pascal Stahr, Jochen Maaß and Henner Gärtner
Robotics 2023, 12(4), 113; https://doi.org/10.3390/robotics12040113 - 04 Aug 2023
Cited by 1 | Viewed by 1552
Abstract
For visually impaired people, orientation and mobility are challenging and require a great deal of concentration. Especially unfamiliar routes are difficult to follow. This paper presents a navigation algorithm based on a geographic information system that can be optimally adapted to the needs [...] Read more.
For visually impaired people, orientation and mobility are challenging and require a great deal of concentration. Especially unfamiliar routes are difficult to follow. This paper presents a navigation algorithm based on a geographic information system that can be optimally adapted to the needs of this user group. A three-stage process is being developed for this purpose. The first step is to check the map against ISO 19157, followed by map augmentation and the generation of a navigable graph. Finally, a new cost function for an A* algorithm is developed to make the best use of the modified map data and adapt it to the user’s needs. It is shown that map data from the geographic information system OpenStreetMap is well suited to the task, although the map data needs to be verified and augmented with additional information before being used. Finally, we compare the presented solution with a standard A* algorithm. Full article
(This article belongs to the Section Agricultural and Field Robotics)
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18 pages, 4445 KiB  
Article
A Hybrid Motion Planning Algorithm for Multi-Mobile Robot Formation Planning
by Haojie Chen, Zifan Wang, Xiaoxu Liu, Wenke Ma, Qiang Wang, Wenjun Zhang and Tan Zhang
Robotics 2023, 12(4), 112; https://doi.org/10.3390/robotics12040112 - 04 Aug 2023
Viewed by 1141
Abstract
This paper addresses the problem of relative position-based formation planning for a leader–follower multi-robot setup, where the robots adjust the formation parameters, such as size and three-dimensional orientation, to avoid collisions and progress toward their goal. Specifically, we develop a virtual sub-target-based obstacle [...] Read more.
This paper addresses the problem of relative position-based formation planning for a leader–follower multi-robot setup, where the robots adjust the formation parameters, such as size and three-dimensional orientation, to avoid collisions and progress toward their goal. Specifically, we develop a virtual sub-target-based obstacle avoidance method, which involves a transitional virtual sub-target that guides the robots to avoid obstacles according to obstacle information, target, and boundary. Moreover, we develop a changing formation strategy to determine the necessity to avoid collisions and a priority-based model to determine which robots move, thus dynamically adjusting the relative distance between the followers and the leader. The backstepping-based sliding motion controller guarantees that the trajectory and velocity tracking errors converge to zero. The proposed robot navigation method can be employed in various environments and types of obstacles, allowing for a formation change. Furthermore, it is efficient and scalable under various numbers of robots. The approach is experimentally verified using three real mobile robots and up to five mobile robots in simulated scenarios. Full article
(This article belongs to the Special Issue The State-of-the-Art of Robotics in Asia)
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20 pages, 901 KiB  
Review
Telepresence in the Recent Literature with a Focus on Robotic Platforms, Applications and Challenges
by Karim Youssef, Sherif Said, Samer Al Kork and Taha Beyrouthy
Robotics 2023, 12(4), 111; https://doi.org/10.3390/robotics12040111 - 01 Aug 2023
Viewed by 2455
Abstract
Three decades ago, telepresence was presented as an idea in the context of remote work and manipulation. Since then, it has evolved into a field combining different technologies and allowing users to have more or less realistic perceptions of immersion in remote environments. [...] Read more.
Three decades ago, telepresence was presented as an idea in the context of remote work and manipulation. Since then, it has evolved into a field combining different technologies and allowing users to have more or less realistic perceptions of immersion in remote environments. This paper reviews telepresence and its recent advances. While not covering all the work conducted in telepresence, this paper provides an array of applications for which telepresence can be envisioned, providing a clear view of the differences between components and functionalities of robotic platforms conceived for telepresence and pointing to the dependence of telepresence on several technological areas. Furthermore, challenges faced by telepresence technologies are shown, with consideration of user experiences. We consider telepresence from different perspectives, focusing on specific parts, making it possible to foresee future directions of research and applications. This review will be useful for researchers working in telepresence and related fields. Full article
(This article belongs to the Section Educational Robotics)
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25 pages, 364 KiB  
Article
Beyond the Metal Flesh: Understanding the Intersection between Bio- and AI Ethics for Robotics in Healthcare
by Auxane Boch, Seamus Ryan, Alexander Kriebitz, Lameck Mbangula Amugongo and Christoph Lütge
Robotics 2023, 12(4), 110; https://doi.org/10.3390/robotics12040110 - 01 Aug 2023
Cited by 2 | Viewed by 3874
Abstract
As we look towards the future of healthcare, integrating Care Robots (CRs) into health systems is a practical approach to address challenges such as an ageing population and caregiver shortages. However, ethical discussions about the impact of CRs on patients, caregivers, healthcare systems, [...] Read more.
As we look towards the future of healthcare, integrating Care Robots (CRs) into health systems is a practical approach to address challenges such as an ageing population and caregiver shortages. However, ethical discussions about the impact of CRs on patients, caregivers, healthcare systems, and society are crucial. This normative research seeks to define an integrative and comprehensive ethical framework for CRs, encompassing a wide range of AI-related issues in healthcare. To build the framework, we combine principles of beneficence, non-maleficence, autonomy, justice, and explainability by integrating the AI4People framework for a Good AI Society and the traditional bioethics perspective. Using the integrated framework, we conduct an ethical assessment of CRs. Next, we identify three key ethical trade-offs and propose remediation strategies for the technology. Finally, we offer design recommendations for responsible development and usage of CRs. In conclusion, our research highlights the critical need for sector-specific ethical discussions in healthcare to fully grasp the potential implications of integrating AI technology. Full article
(This article belongs to the Special Issue Robots and Artificial Intelligence for a Better Future of Health Care)
40 pages, 4900 KiB  
Article
Stability of a Groucho-Style Bounding Run in the Sagittal Plane
by Jeffrey Duperret and Daniel E. Koditschek
Robotics 2023, 12(4), 109; https://doi.org/10.3390/robotics12040109 - 27 Jul 2023
Viewed by 1314
Abstract
This paper develops a three-degree-of-freedom sagittal-plane hybrid dynamical systems model of a Groucho-style bounding quadrupedal run. Simple within-stance controls using a modular architecture yield a closed-form expression for a family of hybrid limit cycles that represent bounding behavior over a range of user-selected [...] Read more.
This paper develops a three-degree-of-freedom sagittal-plane hybrid dynamical systems model of a Groucho-style bounding quadrupedal run. Simple within-stance controls using a modular architecture yield a closed-form expression for a family of hybrid limit cycles that represent bounding behavior over a range of user-selected fore-aft speeds as a function of the model’s kinematic and dynamical parameters. Controls acting on the hybrid transitions are structured so as to achieve a cascade composition of in-place bounding driving the fore-aft degree of freedom, thereby decoupling the linearized dynamics of an approximation to the stride map. Careful selection of the feedback channels used to implement these controls affords infinitesimal deadbeat stability, which is relatively robust against parameter mismatch. Experiments with a physical quadruped reasonably closely match the bounding behavior predicted by the hybrid limit cycle and its stable linearized approximation. Full article
(This article belongs to the Section Sensors and Control in Robotics)
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59 pages, 26407 KiB  
Article
Viewpoint Generation Using Feature-Based Constrained Spaces for Robot Vision Systems
by Alejandro Magaña, Jonas Dirr, Philipp Bauer and Gunther Reinhart
Robotics 2023, 12(4), 108; https://doi.org/10.3390/robotics12040108 - 26 Jul 2023
Cited by 2 | Viewed by 1112
Abstract
The efficient computation of viewpoints while considering various system and process constraints is a common challenge that any robot vision system is confronted with when trying to execute a vision task. Although fundamental research has provided solid and sound solutions for tackling this [...] Read more.
The efficient computation of viewpoints while considering various system and process constraints is a common challenge that any robot vision system is confronted with when trying to execute a vision task. Although fundamental research has provided solid and sound solutions for tackling this problem, a holistic framework that poses its formal description, considers the heterogeneity of robot vision systems, and offers an integrated solution remains unaddressed. Hence, this publication outlines the generation of viewpoints as a geometrical problem and introduces a generalized theoretical framework based on Feature-Based Constrained Spaces (C-spaces) as the backbone for solving it. A C-space can be understood as the topological space that a viewpoint constraint spans, where the sensor can be positioned for acquiring a feature while fulfilling the constraint. The present study demonstrates that many viewpoint constraints can be efficiently formulated as C-spaces, providing geometric, deterministic, and closed solutions. The introduced C-spaces are characterized based on generic domain and viewpoint constraints models to ease the transferability of the present framework to different applications and robot vision systems. The effectiveness and efficiency of the concepts introduced are verified on a simulation-based scenario and validated on a real robot vision system comprising two different sensors. Full article
(This article belongs to the Section Industrial Robots and Automation)
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17 pages, 6331 KiB  
Article
Grasping Profile Control of a Soft Pneumatic Robotic Gripper for Delicate Gripping
by Gridsada Phanomchoeng, Patchara Pitchayawetwongsa, Nattaphat Boonchumanee, Saravut Lin and Ratchatin Chancharoen
Robotics 2023, 12(4), 107; https://doi.org/10.3390/robotics12040107 - 17 Jul 2023
Cited by 2 | Viewed by 2391
Abstract
Soft pneumatic grippers (SPGs) have garnered significant attention and recognition in various industries owing to their remarkable flexibility, safety, and adaptability. They excel in manipulating delicate, irregularly shaped, and soft objects, surpassing the limitations of conventional grippers. However, effective control techniques for managing [...] Read more.
Soft pneumatic grippers (SPGs) have garnered significant attention and recognition in various industries owing to their remarkable flexibility, safety, and adaptability. They excel in manipulating delicate, irregularly shaped, and soft objects, surpassing the limitations of conventional grippers. However, effective control techniques for managing the grasping profile of SPGs are still under development. Simple on–off pressure control using a regulator valve is inadequate for delicate gripping with pneumatic robot grippers. To address this, a synergy pressure control system was implemented. In addition, a proportional–integral–derivative control technique, complemented by an unknown input observer, was devised to control the volume of the soft pneumatic robotic gripper, ensuring its alignment with the desired volume level. The simulation and experimental results provide substantial evidence of the effectiveness of the developed control technique and the unknown input observer in managing the volume and pressure of the gripper. Consequently, this breakthrough empowers precise and delicate gripping actions, enabling the handling of delicate objects such as tofu. Full article
(This article belongs to the Special Issue Editorial Board Members' Collection Series: "Soft Robotics")
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25 pages, 1463 KiB  
Review
Optimizing Exoskeleton Design with Evolutionary Computation: An Intensive Survey
by Fabio Stroppa, Aleyna Soylemez, Huseyin Taner Yuksel, Baris Akbas and Mine Sarac
Robotics 2023, 12(4), 106; https://doi.org/10.3390/robotics12040106 - 17 Jul 2023
Cited by 2 | Viewed by 2409
Abstract
Exoskeleton devices are designed for applications such as rehabilitation, assistance, and haptics. Due to the nature of physical human–machine interaction, designing and operating these devices is quite challenging. Optimization methods lessen the severity of these challenges and help designers develop the device they [...] Read more.
Exoskeleton devices are designed for applications such as rehabilitation, assistance, and haptics. Due to the nature of physical human–machine interaction, designing and operating these devices is quite challenging. Optimization methods lessen the severity of these challenges and help designers develop the device they need. In this paper, we present an extensive and systematic literature search on the optimization methods used for the mechanical design of exoskeletons. We completed the search in the IEEE, ACM, and MDPI databases between 2017 and 2023 using the keywords “exoskeleton”, “design”, and “optimization”. We categorized our findings in terms of which limb (i.e., hand, wrist, arm, or leg) and application (assistive, rehabilitation, or haptic) the exoskeleton was designed for, the optimization metrics (force transmission, workspace, size, and adjustability/calibration), and the optimization method (categorized as evolutionary computation or non-evolutionary computation methods). We discuss our observations with respect to how the optimization methods have been implemented based on our findings. We conclude our paper with suggestions for future research. Full article
(This article belongs to the Special Issue New Trends in Robotics and Mechatronic Technologies)
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16 pages, 580 KiB  
Article
Adaptive Backstepping Integral Sliding Mode Control of a MIMO Separately Excited DC Motor
by Roohma Afifa, Sadia Ali, Mahmood Pervaiz and Jamshed Iqbal
Robotics 2023, 12(4), 105; https://doi.org/10.3390/robotics12040105 - 16 Jul 2023
Cited by 17 | Viewed by 1499
Abstract
This research proposes a robust nonlinear hybrid control approach to the speed control of a multi-input-and-multi-output separately excited DC motor (SEDCM). The motor that was under consideration experienced parametric uncertainties and load disturbances in the weak field region. The proposed technique aims to [...] Read more.
This research proposes a robust nonlinear hybrid control approach to the speed control of a multi-input-and-multi-output separately excited DC motor (SEDCM). The motor that was under consideration experienced parametric uncertainties and load disturbances in the weak field region. The proposed technique aims to merge the benefits of adaptive backstepping (AB) and integral sliding mode control (ISMC) to enhance the overall system’s robustness. The unknown parameters with load disturbances are estimated using an adaptation law. These estimated parameters are incorporated into the controller design, to achieve a highly robust controller. The theoretical stability of the system is proved using the Lyapunov stability criteria. The effectiveness of the proposed AB–ISMC was demonstrated by simulation, to track the reference speed under parametric uncertainties and load disturbances. The control performance of the proposed technique was compared to that of feedback linearization (FBL), conventional sliding mode control (SMC), and AB control laws without and with the adaptation law. Regression parameters, such as integral square error, integral absolute error, and integral time absolute error, were calculated to quantitatively analyze the tracking performance and robustness of the implemented nonlinear control techniques. The simulation results demonstrated that the proposed controller could accurately track the reference speed and exhibited robustness, with steady-state error accuracy. Moreover, AB–ISMC overperformed, compared to the FBL, SMC, AB controller without adaptation law and AB controller with adaptation law, in reducing the settling time by factors of 27%, 67%, 23%, and 21%, respectively, thus highlighting the superior performance of the proposed controller. Full article
(This article belongs to the Special Issue New Trends in Robotics and Mechatronic Technologies)
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14 pages, 6698 KiB  
Article
Skill Fusion in Hybrid Robotic Framework for Visual Object Goal Navigation
by Aleksei Staroverov, Kirill Muravyev, Konstantin Yakovlev and Aleksandr I. Panov
Robotics 2023, 12(4), 104; https://doi.org/10.3390/robotics12040104 - 16 Jul 2023
Cited by 1 | Viewed by 1951
Abstract
In recent years, Embodied AI has become one of the main topics in robotics. For the agent to operate in human-centric environments, it needs the ability to explore previously unseen areas and to navigate to objects that humans want the agent to interact [...] Read more.
In recent years, Embodied AI has become one of the main topics in robotics. For the agent to operate in human-centric environments, it needs the ability to explore previously unseen areas and to navigate to objects that humans want the agent to interact with. This task, which can be formulated as ObjectGoal Navigation (ObjectNav), is the main focus of this work. To solve this challenging problem, we suggest a hybrid framework consisting of both not-learnable and learnable modules and a switcher between them—SkillFusion. The former are more accurate, while the latter are more robust to sensors’ noise. To mitigate the sim-to-real gap, which often arises with learnable methods, we suggest training them in such a way that they are less environment-dependent. As a result, our method showed top results in both the Habitat simulator and during the evaluations on a real robot. Full article
(This article belongs to the Topic Artificial Intelligence in Navigation)
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23 pages, 2530 KiB  
Article
Detection of Hidden Moving Targets by a Group of Mobile Agents with Deep Q-Learning
by Barouch Matzliach, Irad Ben-Gal and Evgeny Kagan
Robotics 2023, 12(4), 103; https://doi.org/10.3390/robotics12040103 - 14 Jul 2023
Viewed by 883
Abstract
In this paper, we propose a solution for the problem of searching for multiple targets by a group of mobile agents with sensing errors of the first and the second types. The agents’ goal is to plan the search and follow its trajectories [...] Read more.
In this paper, we propose a solution for the problem of searching for multiple targets by a group of mobile agents with sensing errors of the first and the second types. The agents’ goal is to plan the search and follow its trajectories that lead to target detection in minimal time. Relying on real sensors’ properties, we assume that the agents can detect the targets in various directions and distances; however, they are exposed to first- and second-type statistical errors. Furthermore, we assume that the agents in the group have errorless communication with each other. No central station or coordinating agent is assumed to control the search. Thus, the search follows a fully distributed decision-making process, in which each agent plans its path independently based on the information about the targets, which is collected independently or received from the other agents. The suggested solution includes two algorithms: the Distributed Expected Information Gain (DEIG) algorithm, which implements dynamic Voronoi partitioning of the search space and plans the paths by maximizing the expected one-step look-ahead information per region, and the Collective Q-max (CQM) algorithm, which finds the shortest paths of the agents in the group by maximizing the cumulative information about the targets’ locations using deep Q-learning techniques. The developed algorithms are compared against previously developed reactive and learning methods, such as the greedy centralized Expected Information Gain (EIG) method. It is demonstrated that these algorithms, specifically the Collective Q-max algorithm, considerably outperform existing solutions. In particular, the proposed algorithms improve the results by 20% to 100% under different scenarios of noisy environments and sensors’ sensitivity. Full article
(This article belongs to the Section AI in Robotics)
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2 pages, 167 KiB  
Editorial
Special Issue “Legged Robots into the Real World”
by Chengxu Zhou
Robotics 2023, 12(4), 102; https://doi.org/10.3390/robotics12040102 - 13 Jul 2023
Viewed by 1057
Abstract
In the landscape of intelligent systems and robotics, legged robots stand out as a fascinating fusion of biological inspiration and engineered design [...] Full article
(This article belongs to the Special Issue Legged Robots into the Real World)
29 pages, 1668 KiB  
Article
Inverse Kinematics of an Anthropomorphic 6R Robot Manipulator Based on a Simple Geometric Approach for Embedded Systems
by Michael Anschober, Raimund Edlinger, Roman Froschauer and Andreas Nüchter
Robotics 2023, 12(4), 101; https://doi.org/10.3390/robotics12040101 - 12 Jul 2023
Cited by 1 | Viewed by 3039
Abstract
This manuscript presents an efficient algorithm for solving the inverse kinematics problem of a 6R robot manipulator to be deployed on embedded control hardware. The proposed method utilizes the geometric relationship between the end-effector and the base of the manipulator, resulting in a [...] Read more.
This manuscript presents an efficient algorithm for solving the inverse kinematics problem of a 6R robot manipulator to be deployed on embedded control hardware. The proposed method utilizes the geometric relationship between the end-effector and the base of the manipulator, resulting in a computationally efficient solution. The approach aims to minimize computational complexity and memory consumption while maintaining the accuracy and real-time performance demonstrated by simulations and verified by experimental results on an embedded system. Furthermore, the manipulator is analyzed in terms of singularities, limits, the workspace, and general solvability. Due to the simplicity of the algorithm, a platform-independent implementation is possible. As a result, the average calculation time is reduced by a factor of five to eight and the average error is decreased by a factor of fifty compared to a powerful analytical solver. Full article
(This article belongs to the Special Issue Advanced Grasping and Motion Control Solutions)
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18 pages, 1423 KiB  
Article
Simplicial Homology Global Optimization of EEG Signal Extraction for Emotion Recognition
by Ahmed Roshdy, Samer Al Kork, Taha Beyrouthy and Amine Nait-ali
Robotics 2023, 12(4), 99; https://doi.org/10.3390/robotics12040099 - 11 Jul 2023
Cited by 2 | Viewed by 1481
Abstract
Emotion recognition is a vital part of human functioning. textcolorredIt enables individuals to respond suitably to environmental events and develop self-awareness. The fast-paced developments in brain–computer interfacing (BCI) technology necessitate that intelligent machines of the future be able to digitize and recognize human [...] Read more.
Emotion recognition is a vital part of human functioning. textcolorredIt enables individuals to respond suitably to environmental events and develop self-awareness. The fast-paced developments in brain–computer interfacing (BCI) technology necessitate that intelligent machines of the future be able to digitize and recognize human emotions. To achieve this, both humans and machines have relied on facial expressions, in addition to other visual cues. While facial expressions are effective in recognizing emotions, they can be artificially replicated and require constant monitoring. In recent years, the use of Electroencephalography (EEG) signals has become a popular method for emotion recognition, thanks to advances in deep learning and machine learning techniques. EEG-based systems for recognizing emotions involve measuring electrical activity in the brain of a subject who is exposed to emotional stimuli such as images, sounds, or videos. Machine learning algorithms are then used to extract features from the electrical activity data that correspond to specific emotional states. The quality of the extracted EEG signal is crucial, as it affects the overall complexity of the system and the accuracy of the machine learning algorithm. This article presents an approach to improve the accuracy of EEG-based emotion recognition systems while reducing their complexity. The approach involves optimizing the number of EEG channels, their placement on the human scalp, and the target frequency band of the measured signal to maximize the difference between high and low arousal levels. The optimization method, called the simplicial homology global optimization (SHGO), is used for this purpose. Experimental results demonstrate that a six-electrode configuration optimally placed can achieve a better level of accuracy than a 14-electrode configuration, resulting in an over 60% reduction in complexity in terms of the number of electrodes. This method demonstrates promising results in improving the efficiency and accuracy of EEG-based emotion recognition systems, which could have implications for various fields, including healthcare, psychology, and human–computer interfacing. Full article
(This article belongs to the Section Sensors and Control in Robotics)
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23 pages, 645 KiB  
Review
Recent Advances and Perspectives in Deep Learning Techniques for 3D Point Cloud Data Processing
by Zifeng Ding, Yuxuan Sun, Sijin Xu, Yan Pan, Yanhong Peng and Zebing Mao
Robotics 2023, 12(4), 100; https://doi.org/10.3390/robotics12040100 - 11 Jul 2023
Cited by 4 | Viewed by 4181
Abstract
In recent years, deep learning techniques for processing 3D point cloud data have seen significant advancements, given their unique ability to extract relevant features and handle unstructured data. These techniques find wide-ranging applications in fields like robotics, autonomous vehicles, and various other computer-vision [...] Read more.
In recent years, deep learning techniques for processing 3D point cloud data have seen significant advancements, given their unique ability to extract relevant features and handle unstructured data. These techniques find wide-ranging applications in fields like robotics, autonomous vehicles, and various other computer-vision applications. This paper reviews the recent literature on key tasks, including 3D object classification, tracking, pose estimation, segmentation, and point cloud completion. The review discusses the historical development of these methods, explores different model architectures, learning algorithms, and training datasets, and provides a comprehensive summary of the state-of-the-art in this domain. The paper presents a critical evaluation of the current limitations and challenges in the field, and identifies potential areas for future research. Furthermore, the emergence of transformative methodologies like PoinTr and SnowflakeNet is examined, highlighting their contributions and potential impact on the field. The potential cross-disciplinary applications of these techniques are also discussed, underscoring the broad scope and impact of these developments. This review fills a knowledge gap by offering a focused and comprehensive synthesis of recent research on deep learning techniques for 3D point cloud data processing, thereby serving as a useful resource for both novice and experienced researchers in the field. Full article
(This article belongs to the Special Issue Immersive Teleoperation and AI)
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0 pages, 7653 KiB  
Article
Type Synthesis of 5-DOF Hybrid (Parallel-Serial) Manipulators Designed from Open Kinematic Chains
by Anton Antonov, Alexey Fomin, Victor Glazunov, Daniil Petelin and Gleb Filippov
Robotics 2023, 12(4), 98; https://doi.org/10.3390/robotics12040098 - 09 Jul 2023
Cited by 1 | Viewed by 1389
Abstract
The article proposes an approach for synthesizing hybrid (parallel-serial) manipulators with five degrees of freedom (5-DOF) using open kinematic chains. The method idea consists in taking an open kinematic chain, selecting a subchain within it, and replacing the subchain with a parallel mechanism. [...] Read more.
The article proposes an approach for synthesizing hybrid (parallel-serial) manipulators with five degrees of freedom (5-DOF) using open kinematic chains. The method idea consists in taking an open kinematic chain, selecting a subchain within it, and replacing the subchain with a parallel mechanism. The article considers 5-DOF open chains and 3-DOF subchains, substituted for 3-DOF parallel mechanisms with the same motion pattern as the subchain. Thus, synthesized hybrid manipulators have a 3-DOF parallel part and a 2-DOF serial part. First, we grouped 26 structures of open chains with revolute and prismatic joints into five types and 78 subtypes. Next, for each type, we selected one subtype and presented several hybrid mechanisms that can correspond to it. We considered hybrid manipulators that included 3-DOF parallel mechanisms with planar, spherical, and other commonly used motion types. The suggested synthesis method is intuitive for a designer, and it does not need any mathematical formulations like screw theory or group theory approaches. Full article
(This article belongs to the Special Issue Kinematics and Robot Design VI, KaRD2023)
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9 pages, 1790 KiB  
Article
ChatGPT-Enabled daVinci Surgical Robot Prototype: Advancements and Limitations
by Abhilash Pandya
Robotics 2023, 12(4), 97; https://doi.org/10.3390/robotics12040097 - 06 Jul 2023
Cited by 2 | Viewed by 2591
Abstract
The daVinci Surgical Robot has revolutionized minimally invasive surgery by enabling greater accuracy and less-invasive procedures. However, the system lacks the advanced features and autonomy necessary for it to function as a true partner. To enhance its usability, we introduce the implementation of [...] Read more.
The daVinci Surgical Robot has revolutionized minimally invasive surgery by enabling greater accuracy and less-invasive procedures. However, the system lacks the advanced features and autonomy necessary for it to function as a true partner. To enhance its usability, we introduce the implementation of a ChatGPT-based natural language robot interface. Overall, our integration of a ChatGPT-enabled daVinci Surgical Robot has potential to expand the utility of the surgical platform by supplying a more accessible interface. Our system can listen to the operator speak and, through the ChatGPT-enabled interface, translate the sentence and context to execute specific commands to alter the robot’s behavior or to activate certain features. For instance, the surgeon could say (even in Spanish) “please track my left tool” and the system will translate the sentence into a specific track command. This specific error-checked command will then be sent to the hardware, which will respond by controlling the camera of the system to continuously adjust and center the left tool in the field of view. We have implemented many commands, including “Find my tools” (tools that are not in the field of view) or start/stop recording, that can be triggered based on a natural conversational context. Here, we present the details of our prototype system, give some accuracy results, and explore its potential implications and limitations. We also discuss how artificial intelligence tools (such as ChatGPT) of the future could be leveraged by robotic surgeons to reduce errors and enhance the efficiency and safety of surgical procedures and even ask for help. Full article
(This article belongs to the Section AI in Robotics)
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23 pages, 38125 KiB  
Article
An Open PLC-Based Robot Control System for 3D Concrete Printing
by Daniel Kajzr, Tomas Myslivec and Josef Cernohorsky
Robotics 2023, 12(4), 96; https://doi.org/10.3390/robotics12040096 - 03 Jul 2023
Viewed by 3264
Abstract
Three-dimensional concrete printing technology is currently a very topical and developing subject. There is a large number of applications worldwide where this technology can be used. In connection with this technology, the development of custom industrial robotic systems and their control is essential. [...] Read more.
Three-dimensional concrete printing technology is currently a very topical and developing subject. There is a large number of applications worldwide where this technology can be used. In connection with this technology, the development of custom industrial robotic systems and their control is essential. Conventional closed-loop control system platforms do not provide sufficiently flexible solutions. This paper presents a control system for a unique printing robot that, thanks to its openness and unified platform, will enable simple and fast analysis and testing of key aspects in terms of control and guidance of the printing robot for additive manufacturing applications in the construction industry. The aim of this paper is to introduce the concept of an open PLC-based control system and to demonstrate its usefulness in the task of designing and implementing model-based control. All steps, from the analysis of the printing robot itself and identification of inertial parameters to the actual design and implementation of the control, can be executed in a unified Matlab/Simulink environment using various add-ons and toolboxes thanks to the open control system platform. This solution brings significant savings in terms of programming and prototyping time. The open control system was used to control an experimental model of a printing robot, serving as a test bed for the final version of the printing robot, and the results obtained were evaluated. Full article
(This article belongs to the Section Intelligent Robots and Mechatronics)
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0 pages, 4513 KiB  
Article
A Newly-Designed Wearable Robotic Hand Exoskeleton Controlled by EMG Signals and ROS Embedded Systems
by Ismail Ben Abdallah and Yassine Bouteraa
Robotics 2023, 12(4), 95; https://doi.org/10.3390/robotics12040095 - 01 Jul 2023
Cited by 2 | Viewed by 2819 | Retraction
Abstract
One of the most difficult parts of stroke therapy is hand mobility recovery. Indeed, stroke is a serious medical disorder that can seriously impair hand and locomotor movement. To improve hand function in stroke patients, new medical technologies, such as various wearable devices [...] Read more.
One of the most difficult parts of stroke therapy is hand mobility recovery. Indeed, stroke is a serious medical disorder that can seriously impair hand and locomotor movement. To improve hand function in stroke patients, new medical technologies, such as various wearable devices and rehabilitation therapies, are being developed. In this study, a new design of electromyography (EMG)-controlled 3D-printed hand exoskeleton is presented. The exoskeleton was created to help stroke victims with their gripping abilities. Computer-aided design software was used to create the device’s 3D architecture, which was then printed using a polylactic acid filament. For online classifications, the performance of two classifiers—the support vector machine (SVM) and the K-near neighbor (KNN)—was compared. The Robot Operating System (ROS) connects all the various system nodes and generates the decision for the hand exoskeleton. The selected classifiers had high accuracy, reaching up to 98% for online classification performed with healthy subjects. These findings imply that the new wearable exoskeleton, which could be controlled in accordance with the subjects’ motion intentions, could aid in hand rehabilitation for a wider motion range and greater dexterity. Full article
(This article belongs to the Section Medical Robotics and Service Robotics)
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27 pages, 23361 KiB  
Article
Design and Performance Analysis of a Torsional Soft Actuator Based on Hyperelastic Materials
by Zhengyun Xu, Haiqiang Liu, Weihua Feng, Huaming Yang, Xin Nie and Rougang Zhou
Robotics 2023, 12(4), 94; https://doi.org/10.3390/robotics12040094 - 28 Jun 2023
Cited by 1 | Viewed by 1180
Abstract
Conducting research on soft robots is crucial as there are still many problems that need to be resolved in the areas of material selection, structure design and manufacture, and drive control. Soft manipulators, a subset of soft robots, are now a popular area [...] Read more.
Conducting research on soft robots is crucial as there are still many problems that need to be resolved in the areas of material selection, structure design and manufacture, and drive control. Soft manipulators, a subset of soft robots, are now a popular area of study for many researchers. In comparison to typical manipulators, soft manipulators feature a high degree of gripping flexibility and a basic morphological structure. They are composed of flexible materials. They have a wide range of potential applications in healthcare, rehabilitation, bionics, and detection, and they can compensate for the drawbacks of rigid manipulators in some use scenarios. A modular soft-body torsional gripping system is developed after a torsional and gripping actuator is conceived and constructed, and its performance examined. The torsion actuator and the grasping actuator can be combined in the system in a modular fashion. With the help of RGB-D vision algorithms, this multi-modular setup makes it possible to combine soft actuators with various twisting degrees and achieve exact gripping. Through pneumatic control, the target object is precisely grasped and rotated at various angles, enabling the rotation of the target object in three dimensions. Full article
(This article belongs to the Special Issue The State-of-the-Art of Robotics in Asia)
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35 pages, 7889 KiB  
Review
Classical and Heuristic Approaches for Mobile Robot Path Planning: A Survey
by Jaafar Ahmed Abdulsaheb and Dheyaa Jasim Kadhim
Robotics 2023, 12(4), 93; https://doi.org/10.3390/robotics12040093 - 27 Jun 2023
Cited by 8 | Viewed by 4499
Abstract
The most important research area in robotics is navigation algorithms. Robot path planning (RPP) is the process of choosing the best route for a mobile robot to take before it moves. Finding an ideal or nearly ideal path is referred to as “path [...] Read more.
The most important research area in robotics is navigation algorithms. Robot path planning (RPP) is the process of choosing the best route for a mobile robot to take before it moves. Finding an ideal or nearly ideal path is referred to as “path planning optimization.” Finding the best solution values that satisfy a single or a number of objectives, such as the shortest, smoothest, and safest path, is the goal. The objective of this study is to present an overview of navigation strategies for mobile robots that utilize three classical approaches, namely: the roadmap approach (RM), cell decomposition (CD), and artificial potential fields (APF), in addition to eleven heuristic approaches, including the genetic algorithm (GA), ant colony optimization (ACO), artificial bee colony (ABC), gray wolf optimization (GWO), shuffled frog-leaping algorithm (SFLA), whale optimization algorithm (WOA), bacterial foraging optimization (BFO), firefly (FF) algorithm, cuckoo search (CS), and bat algorithm (BA), which may be used in various environmental situations. Multiple issues, including dynamic goals, static and dynamic environments, multiple robots, real-time simulation, kinematic analysis, and hybrid algorithms, are addressed in a different set of articles presented in this study. A discussion, as well as thorough tables and charts, will be presented at the end of this work to help readers understand what types of strategies for path planning are developed for use in a wide range of ecological contexts. Therefore, this work’s main contribution is that it provides a broad view of robot path planning, which will make it easier for scientists to study the topic in the near future. Full article
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29 pages, 6579 KiB  
Article
Non-Prehensile Manipulation Actions and Visual 6D Pose Estimation for Fruit Grasping Based on Tactile Sensing
by Marco Costanzo, Marco De Simone, Sara Federico and Ciro Natale
Robotics 2023, 12(4), 92; https://doi.org/10.3390/robotics12040092 - 25 Jun 2023
Viewed by 1639
Abstract
Robotic manipulation in cluttered environments is one of the challenges roboticists are currently facing. When the objects to handle are delicate fresh fruits, grasping is even more challenging. Detecting and localizing fruits with the accuracy necessary to grasp them is very difficult due [...] Read more.
Robotic manipulation in cluttered environments is one of the challenges roboticists are currently facing. When the objects to handle are delicate fresh fruits, grasping is even more challenging. Detecting and localizing fruits with the accuracy necessary to grasp them is very difficult due to the large variability in the aspect and dimensions of each item. This paper proposes a solution that exploits a state-of-the-art neural network and a novel enhanced 6D pose estimation method that integrates the depth map with the neural network output. Even with an accurate localization, grasping fruits with a suitable force to avoid slippage and damage at the same time is another challenge. This work solves this issue by resorting to a grasp controller based on tactile sensing. Depending on the specific application scenario, grasping a fruit might be impossible without colliding with other objects or other fruits. Therefore, a non-prehensile manipulation action is here proposed to push items hindering the grasp of a detected fruit. The pushing from an initial location to a target one is performed by a model predictive controller taking into account the unavoidable delay in the perception and computing pipeline of the robotic system. Experiments with real fresh fruits demonstrate that the overall proposed approach allows a robot to successfully grasp apples in various situations. Full article
(This article belongs to the Special Issue Robotics and AI for Precision Agriculture)
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21 pages, 9773 KiB  
Article
Computational Systems Design of Low-Cost Lightweight Robots
by Akhil Sathuluri, Anand Vazhapilli Sureshbabu, Jintin Frank, Maximilian Amm and Markus Zimmermann
Robotics 2023, 12(4), 91; https://doi.org/10.3390/robotics12040091 - 25 Jun 2023
Viewed by 1865
Abstract
With the increased demand for customisation, developing task-specific robots for industrial and personal applications has become essential. Collaborative robots are often preferred over conventional industrial robots in human-centred production environments. However, fixed architecture robots lack the ability to adapt to changing user demands, [...] Read more.
With the increased demand for customisation, developing task-specific robots for industrial and personal applications has become essential. Collaborative robots are often preferred over conventional industrial robots in human-centred production environments. However, fixed architecture robots lack the ability to adapt to changing user demands, while modular, reconfigurable robots provide a quick and affordable alternative. Standardised robot modules often derive their characteristics from conventional industrial robots, making them expensive and bulky and potentially limiting their wider adoption. To address this issue, the current work proposes a top-down multidisciplinary computational design strategy emphasising the low cost and lightweight attributes of modular robots within two consecutive optimisation problems. The first step employs an informed search strategy to explore the design space of robot modules to identify a low-cost robot architecture and controller. The second step employs dynamics-informed structural optimisation to reduce the robot’s net weight. The proposed methodology is demonstrated on a set of example requirements, illustrating that (1) the robot modules allow exploring non-intuitive robot architectures, (2) the structural mass of the resulting robot is 16 % lower compared to a robot designed using conventional aluminium tubes, and (3) the designed modules ensure the physical feasibility of the robots produced. Full article
(This article belongs to the Special Issue New Trends in Robotics and Mechatronic Technologies)
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