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Robotics, Volume 8, Issue 3 (September 2019)

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Cover Story (view full-size image) Exoskeletons are an increasingly popular technology in industrial contexts. However, most of the [...] Read more.
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Open AccessArticle
Virtualization of Robotic Hands Using Mobile Devices
Robotics 2019, 8(3), 81; https://doi.org/10.3390/robotics8030081 - 16 Sep 2019
Viewed by 317
Abstract
This article presents a multiplatform application for the tele-operation of a robot hand using virtualization in Unity 3D. This approach grants usability to users that need to control a robotic hand, allowing supervision in a collaborative way. This paper focuses on a user [...] Read more.
This article presents a multiplatform application for the tele-operation of a robot hand using virtualization in Unity 3D. This approach grants usability to users that need to control a robotic hand, allowing supervision in a collaborative way. This paper focuses on a user application designed for the 3D virtualization of a robotic hand and the tele-operation architecture. The designed system allows for the simulation of any robotic hand. It has been tested with the virtualization of the four-fingered Allegro Hand of SimLab with 16 degrees of freedom, and the Shadow hand with 24 degrees of freedom. The system allows for the control of the position of each finger by means of joint and Cartesian co-ordinates. All user control interfaces are designed using Unity 3D, such that a multiplatform philosophy is achieved. The server side allows the user application to connect to a ROS (Robot Operating System) server through a TCP/IP socket, to control a real hand or to share a simulation of it among several users. If a real robot hand is used, real-time control and feedback of all the joints of the hand is communicated to the set of users. Finally, the system has been tested with a set of users with satisfactory results. Full article
(This article belongs to the Special Issue Robotics in Spain 2019)
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Open AccessArticle
Analysis of the Compliance Properties of an Industrial Robot with the Mozzi Axis Approach
Robotics 2019, 8(3), 80; https://doi.org/10.3390/robotics8030080 - 11 Sep 2019
Viewed by 246
Abstract
In robotic processes, the compliance of the robot arm plays a very important role. In some conditions, for example, in robotic assembly, robot arm compliance can compensate for small position and orientation errors of the end-effector. In other processes, like machining, robot compliance [...] Read more.
In robotic processes, the compliance of the robot arm plays a very important role. In some conditions, for example, in robotic assembly, robot arm compliance can compensate for small position and orientation errors of the end-effector. In other processes, like machining, robot compliance may generate chatter vibrations with an impairment in the quality of the machined surface. In industrial robots, the compliance of the end-effector is chiefly due to joint compliances. In this paper, joint compliances of a serial six-joint industrial robot are identified with a novel modal method making use of specific modes of vibration dominated by the compliance of only one joint. Then, in order to represent the effect of the identified compliances on robot performance in an intuitive and geometric way, a novel kinematic method based on the concept of “Mozzi axis” of the end-effector is presented and discussed. Full article
(This article belongs to the Special Issue Advances in Italian Robotics)
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Open AccessArticle
Model-Based Grasping of Unknown Objects from a Random Pile
Robotics 2019, 8(3), 79; https://doi.org/10.3390/robotics8030079 - 06 Sep 2019
Viewed by 355
Abstract
Grasping an unknown object in a pile is no easy task for a robot—it is often difficult to distinguish different objects; objects occlude one another; object proximity limits the number of feasible grasps available; and so forth. In this paper, we propose a [...] Read more.
Grasping an unknown object in a pile is no easy task for a robot—it is often difficult to distinguish different objects; objects occlude one another; object proximity limits the number of feasible grasps available; and so forth. In this paper, we propose a simple approach to grasping unknown objects one by one from a random pile. The proposed method is divided into three main actions—over-segmentation of the images, a decision algorithm and ranking according to a grasp robustness index. Thus, the robot is able to distinguish the objects from the pile, choose the best candidate for grasping among these objects, and pick the most robust grasp for this candidate. With this approach, we can clear out a random pile of unknown objects, as shown in the experiments reported herein. Full article
(This article belongs to the Section Robotics & Automation)
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Open AccessArticle
Trajectory Analysis for the MASAR: A New Modular and Single-Actuator Robot
Robotics 2019, 8(3), 78; https://doi.org/10.3390/robotics8030078 - 05 Sep 2019
Viewed by 330
Abstract
Single-actuator mobile robots offer the benefits of low energy consumption, low weight and size, and low cost, but their motion is typically only one-dimensional. By using auxiliary binary mechanisms that redirect and channel the driving force of their only actuator in different ways, [...] Read more.
Single-actuator mobile robots offer the benefits of low energy consumption, low weight and size, and low cost, but their motion is typically only one-dimensional. By using auxiliary binary mechanisms that redirect and channel the driving force of their only actuator in different ways, it is possible for these robots to perform higher-dimensional motions, such as walking straight, steering, or jumping, with only one motor. This paper presents the MASAR, a new Modular And Single-Actuator Robot that carries a single motor and several adhesion pads. By alternately releasing or attaching these adhesion pads to the environment, the proposed robot is able to pivot about different axes using only one motor, with the possibility of performing concave plane transitions or combining with other identical modules to build more complex reconfigurable robots. In this paper, we solve the planar trajectory tracking problem of this robot for polygonal paths made up of sequences of segments, which may include narrow corridors that are difficult to traverse. We propose a locomotion based on performing rotations of 180 , which we demonstrate to be the minimum-time solution for long trajectories, and a near-optimal solution for shorter ones. Full article
(This article belongs to the Special Issue Robotics in Spain 2019)
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Open AccessArticle
Design and Implementation of a Quadruped Amphibious Robot Using Duck Feet
Robotics 2019, 8(3), 77; https://doi.org/10.3390/robotics8030077 - 05 Sep 2019
Viewed by 349
Abstract
Roaming complexity in terrains and unexpected environments pose significant difficulties in robotic exploration of an area. In a broader sense, robots have to face two common tasks during exploration, namely, walking on the drylands and swimming through the water. This research aims to [...] Read more.
Roaming complexity in terrains and unexpected environments pose significant difficulties in robotic exploration of an area. In a broader sense, robots have to face two common tasks during exploration, namely, walking on the drylands and swimming through the water. This research aims to design and develop an amphibious robot, which incorporates a webbed duck feet design to walk on different terrains, swim in the water, and tackle obstructions on its way. The designed robot is compact, easy to use, and also has the abilities to work autonomously. Such a mechanism is implemented by designing a novel robotic webbed foot consisting of two hinged plates. Because of the design, the webbed feet are able to open and close with the help of water pressure. Klann linkages have been used to convert rotational motion to walking and swimming for the animal’s gait. Because of its amphibian nature, the designed robot can be used for exploring tight caves, closed spaces, and moving on uneven challenging terrains such as sand, mud, or water. It is envisaged that the proposed design will be appreciated in the industry to design amphibious robots in the near future. Full article
(This article belongs to the Special Issue Robotics in Extreme Environments)
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Open AccessArticle
An Architecture for the Integration of Robots and Sensors for the Care of the Elderly in an Ambient Assisted Living Environment
Robotics 2019, 8(3), 76; https://doi.org/10.3390/robotics8030076 - 03 Sep 2019
Viewed by 370
Abstract
In this paper, the development of an assistance system for the elderly that combines robots with a network of sensors and actuators is described. The architecture was developed with the aim of interaction. With this reason, the system incorporates particular solutions that are [...] Read more.
In this paper, the development of an assistance system for the elderly that combines robots with a network of sensors and actuators is described. The architecture was developed with the aim of interaction. With this reason, the system incorporates particular solutions that are adaptable to the needs of the user, such as a pyramid interaction system, a telepresence robot, a biometric bracelet, and others. In the software, the system is composed of two servers: local and web. The local server is in charge of different modules that interact with direct users and their needs. The web server provides different facilities to external users to access the system remotely. A use case is analyzed where the proposed system is validated. Full article
(This article belongs to the Special Issue Robotics in Spain 2019)
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Open AccessArticle
People Detection and Tracking Using LIDAR Sensors
Robotics 2019, 8(3), 75; https://doi.org/10.3390/robotics8030075 - 31 Aug 2019
Viewed by 461
Abstract
The tracking of people is an indispensable capacity in almost any robotic application. A relevant case is the @home robotic competitions, where the service robots have to demonstrate that they possess certain skills that allow them to interact with the environment and the [...] Read more.
The tracking of people is an indispensable capacity in almost any robotic application. A relevant case is the @home robotic competitions, where the service robots have to demonstrate that they possess certain skills that allow them to interact with the environment and the people who occupy it; for example, receiving the people who knock at the door and attending them as appropriate. Many of these skills are based on the ability to detect and track a person. It is a challenging problem, particularly when implemented using low-definition sensors, such as Laser Imaging Detection and Ranging (LIDAR) sensors, in environments where there are several people interacting. This work describes a solution based on a single LIDAR sensor to maintain a continuous identification of a person in time and space. The system described is based on the People Tracker package, aka PeTra, which uses a convolutional neural network to identify person legs in complex environments. A new feature has been included within the system to correlate over time the people location estimates by using a Kalman filter. To validate the solution, a set of experiments have been carried out in a test environment certified by the European Robotic League. Full article
(This article belongs to the Special Issue Robotics in Spain 2019)
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Open AccessReview
Heterogeneous Map Merging: State of the Art
Robotics 2019, 8(3), 74; https://doi.org/10.3390/robotics8030074 - 20 Aug 2019
Viewed by 584
Abstract
Multi-robot mapping and environment modeling have several advantages that make it an attractive alternative to the mapping with a single robot: faster exploration, higher fault tolerance, richer data due to different sensors being used by different systems. However, the environment modeling with several [...] Read more.
Multi-robot mapping and environment modeling have several advantages that make it an attractive alternative to the mapping with a single robot: faster exploration, higher fault tolerance, richer data due to different sensors being used by different systems. However, the environment modeling with several robotic systems operating in the same area causes problems of higher-order—acquired knowledge fusion and synchronization over time, revealing the same environment properties using different sensors with different technical specifications. While the existing robot map and environment model merging techniques allow merging certain homogeneous maps, the possibility to use sensors of different physical nature and different mapping algorithms is limited. The resulting maps from robots with different specifications are heterogeneous, and even though some research on how to merge fundamentally different maps exists, it is limited to specific applications. This research reviews the state of the art in homogeneous and heterogeneous map merging and illustrates the main research challenges in the area. Six factors are identified that influence the outcome of map merging: (1) robotic platform hardware configurations, (2) map representation types, (3) mapping algorithms, (4) shared information between robots, (5) relative positioning information, (6) resulting global maps. Full article
(This article belongs to the Special Issue Latest Artificial Intelligence Research Output 2018)
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Open AccessArticle
Additive Manufacturing as an Essential Element in the Teaching of Robotics
Robotics 2019, 8(3), 73; https://doi.org/10.3390/robotics8030073 - 20 Aug 2019
Viewed by 608
Abstract
This paper aims to describe how additive manufacturing can be useful in enhancing a robotic course, allowing students to focus on all aspects of the multidisciplinary components of this subject. A three-year experience of the course of “robotic system design” is presented to [...] Read more.
This paper aims to describe how additive manufacturing can be useful in enhancing a robotic course, allowing students to focus on all aspects of the multidisciplinary components of this subject. A three-year experience of the course of “robotic system design” is presented to support the validity of the use of this technology in teaching. This course is specifically aimed at Master of Science (MSc) Mechanical Engineering students and therefore requires one to view the subject in all its aspects including those which are not conventionally taken into consideration such as mechanical design, prototyping and the final realization. Full article
(This article belongs to the Special Issue Kinematics and Robot Design II, KaRD2019)
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Open AccessFeature PaperArticle
Performance Evaluation of a Sensor Concept for Solving the Direct Kinematics Problem of General Planar 3-RPR Parallel Mechanisms by Using Solely the Linear Actuators’ Orientations
Robotics 2019, 8(3), 72; https://doi.org/10.3390/robotics8030072 - 16 Aug 2019
Viewed by 862
Abstract
In this paper, we experimentally evaluate the performance of a sensor concept for solving the direct kinematics problem of a general planar 3-RPR parallel mechanism by using solely the linear actuators’ orientations. At first, we review classical methods for solving the direct kinematics [...] Read more.
In this paper, we experimentally evaluate the performance of a sensor concept for solving the direct kinematics problem of a general planar 3-RPR parallel mechanism by using solely the linear actuators’ orientations. At first, we review classical methods for solving the direct kinematics problem of parallel mechanisms and discuss their disadvantages on the example of the general planar 3-RPR parallel mechanism, a planar parallel robot with two translational and one rotational degrees of freedom, where P denotes active prismatic joints and R denotes passive revolute joints. In order to avoid these disadvantages, we present a sensor concept together with an analytical formulation for solving the direct kinematics problem of a general planar 3-RPR parallel mechanism where the number of possible assembly modes can be significantly reduced when the linear actuators’ orientations are used instead of their lengths. By measuring the orientations of the linear actuators, provided, for example, by inertial measurement units, only two assembly modes exist. Finally, we investigate the accuracy of our direct kinematics solution under static as well as dynamic conditions by performing experiments on a specially designed prototype. We also investigate the solution formulation’s amplification of measurement noise on the calculated pose and show that the Cramér-Rao lower bound can be used to estimate the lower bound of the expected variances for a specific pose based exclusively on the variances of the linear actuators’ orientations. Full article
(This article belongs to the Special Issue Kinematics and Robot Design II, KaRD2019)
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Open AccessTechnical Note
Development of a Practical Tool for Designing Multi-Robot Systems in Pick-and-Place Applications
Robotics 2019, 8(3), 71; https://doi.org/10.3390/robotics8030071 - 12 Aug 2019
Viewed by 690
Abstract
Pick-and-place manipulators have become one of the principal components of almost all manufacturing plants. The process of sizing the number of manipulators required to efficiently carry out pick-and-place tasks depends on the complexities of such plants, the characteristics of the production line and [...] Read more.
Pick-and-place manipulators have become one of the principal components of almost all manufacturing plants. The process of sizing the number of manipulators required to efficiently carry out pick-and-place tasks depends on the complexities of such plants, the characteristics of the production line and the particular requirements. These aspects tend to make the sizing procedure rather complex and time consuming. Moreover, the results are closely linked to the accuracy of the input data that is usually, especially in the initial stages, unreliable and haphazard. To face these issues, the simulation tools currently available in the market are not always suitable. In this paper, a practical procedure to size the number of manipulators required in any particular plant to perform pick-and-place tasks is presented. This procedure results in a relatively simple tool capable of calculating the number of robots required in a line knowing the layout, type of robot to be used, and production characteristics. This tool is able to simulate the different distribution of goods on the line as well as the required strategies for picking in a multi-robot environment to test several production situations and assess the accuracy of the sizing. Full article
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Open AccessArticle
Optimization of a Kitting Line: A Case Study
Robotics 2019, 8(3), 70; https://doi.org/10.3390/robotics8030070 - 07 Aug 2019
Viewed by 642
Abstract
Assembly kitting lines typically deal with components that present different quantities in the final kit. Re-configurable feeders are not advisable for low quantity components since this solution leads to high inefficiency, due to the time required for retooling and for the feeding rate [...] Read more.
Assembly kitting lines typically deal with components that present different quantities in the final kit. Re-configurable feeders are not advisable for low quantity components since this solution leads to high inefficiency, due to the time required for retooling and for the feeding rate unbalance between the components. On the other hand a fully flexible feeder can increase the flexibility of the system at the cost of reducing the throughput. An assembly kitting problem was therefore addressed in different ways for low quantity components and high quantity components, studying the two different subsystems that compose a hybrid flexible assembly system. To optimize the re-configurable feeders, which supply the high quantity components, the opening sequence of a system composed by several hoppers was analyzed. We propose a solution which replaces the weighing device with a vision inspection system, showing its impact on the productivity of the line. A model coded into a Matlab script was developed to perform the optimization of the system and understand its behavior. Furthermore a fully flexible assembly system was developed in the laboratory in order to test the kitting of the low quantity components with the proposed subsystem. Finally the Overall Equipment Effectiveness of the line was calculated to evaluate the possible improvements obtained by the proposed solution. Full article
(This article belongs to the Special Issue Advances in Italian Robotics)
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Open AccessReview
Towards Functional Mobile Microrobotic Systems
Robotics 2019, 8(3), 69; https://doi.org/10.3390/robotics8030069 - 07 Aug 2019
Viewed by 715
Abstract
This paper presents our work over the last decade in developing functional microrobotic systems, which include wireless actuation of microrobots to traverse complex surfaces, addition of sensing capabilities, and independent actuation of swarms of microrobots. We will discuss our work on the design, [...] Read more.
This paper presents our work over the last decade in developing functional microrobotic systems, which include wireless actuation of microrobots to traverse complex surfaces, addition of sensing capabilities, and independent actuation of swarms of microrobots. We will discuss our work on the design, fabrication, and testing of a number of different mobile microrobots that are able to achieve these goals. These microrobots include the microscale magnetorestrictive asymmetric bimorph microrobot ( μ MAB), our first attempt at magnetic actuation in the microscale; the microscale tumbling microrobot ( μ TUM), our microrobot capable of traversing complex surfaces in both wet and dry conditions; and the micro-force sensing magnetic microrobot ( μ FSMM), which is capable of real-time micro-force sensing feedback to the user as well as intuitive wireless actuation. Additionally, we will present our latest results on using local magnetic field actuation for independent control of multiple microrobots in the same workspace for microassembly tasks. Full article
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Open AccessArticle
Modeling Parallel Robot Kinematics for 3T2R and 3T3R Tasks Using Reciprocal Sets of Euler Angles
Robotics 2019, 8(3), 68; https://doi.org/10.3390/robotics8030068 - 06 Aug 2019
Viewed by 745
Abstract
Industrial manipulators and parallel robots are often used for tasks, such as drilling or milling, that require three translational, but only two rotational degrees of freedom (“3T2R”). While kinematic models for specific mechanisms for these tasks exist, a general kinematic model for parallel [...] Read more.
Industrial manipulators and parallel robots are often used for tasks, such as drilling or milling, that require three translational, but only two rotational degrees of freedom (“3T2R”). While kinematic models for specific mechanisms for these tasks exist, a general kinematic model for parallel robots is still missing. This paper presents the definition of the rotational component of kinematic constraints equations for parallel robots based on two reciprocal sets of Euler angles for the end-effector orientation and the orientation residual. The method allows completely removing the redundant coordinate in 3T2R tasks and to solve the inverse kinematics for general serial and parallel robots with the gradient descent algorithm. The functional redundancy of robots with full mobility is exploited using nullspace projection. Full article
(This article belongs to the Special Issue Kinematics and Robot Design II, KaRD2019)
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Open AccessArticle
Pinch Grasp and Suction for Delicate Object Manipulations Using Modular Anthropomorphic Robotic Gripper with Soft Layer Enhancements
Robotics 2019, 8(3), 67; https://doi.org/10.3390/robotics8030067 - 06 Aug 2019
Viewed by 812
Abstract
This paper is an extension of our previous work about a modular anthropomorphic robotic hand with soft enhancements focusing on simultaneous pinch grasp and suction-based object manipulations. The base structure is a tendon-driven robotic hand comprising five fingers and a palm. Each finger [...] Read more.
This paper is an extension of our previous work about a modular anthropomorphic robotic hand with soft enhancements focusing on simultaneous pinch grasp and suction-based object manipulations. The base structure is a tendon-driven robotic hand comprising five fingers and a palm. Each finger consists of two rigid links covered with soft enhancements. The soft enhancements are like the skin and tissues of the robotic hand. The tip of the finger is equipped with a suction module which can be actuated by regulating negative pressure to the soft layers. While our previous work dealt with the rationale behind and the structure of the modular design with kinematic analysis, this paper focuses on analyzing two specific capabilities of the gripper—pinch grasp and suction modality. Experiments validate that the proposed gripper together with the soft enhancement layers is capable of performing delicate single finger suction-based manipulation tasks and two-finger pinch grasp tasks. Full article
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Open AccessArticle
Reconfiguration Analysis of a 3-DOF Parallel Mechanism
Robotics 2019, 8(3), 66; https://doi.org/10.3390/robotics8030066 - 02 Aug 2019
Viewed by 744
Abstract
This paper deals with the reconfiguration analysis of a 3-DOF (degrees-of-freedom) parallel manipulator (PM) which belongs to the cylindrical parallel mechanisms family. The PM is composed of a base and a moving platform shaped as equilateral triangles connected by three serial kinematic chains [...] Read more.
This paper deals with the reconfiguration analysis of a 3-DOF (degrees-of-freedom) parallel manipulator (PM) which belongs to the cylindrical parallel mechanisms family. The PM is composed of a base and a moving platform shaped as equilateral triangles connected by three serial kinematic chains (legs). Two legs are composed of two universal (U) joints connected by a prismatic (P) joint. The third leg is composed of a revolute (R) joint connected to the base, a prismatic joint and universal joint in sequence. A set of constraint equations of the 1-RPU−2-UPU PM is derived and solved in terms of the Euler parameter quaternion (a.k.a. Euler-Rodrigues quaternion) representing the orientation of the moving platform and of the Cartesian coordinates of the reference point on the moving platform. It is found that the PM may undergo either the 3-DOF PPR or the 3-DOF planar operation mode only when the base and the moving platform are identical. The transition configuration between the operation modes is also identified. Full article
(This article belongs to the Special Issue Kinematics and Robot Design II, KaRD2019)
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Open AccessArticle
Mechanical and Control Design of an Industrial Exoskeleton for Advanced Human Empowering in Heavy Parts Manipulation Tasks
Robotics 2019, 8(3), 65; https://doi.org/10.3390/robotics8030065 - 02 Aug 2019
Viewed by 792
Abstract
Exoskeleton robots are a rising technology in industrial contexts to assist humans in onerous applications. Mechanical and control design solutions are intensively investigated to achieve a high performance human-robot collaboration (e.g., transparency, ergonomics, safety, etc.). However, the most of the investigated solutions involve [...] Read more.
Exoskeleton robots are a rising technology in industrial contexts to assist humans in onerous applications. Mechanical and control design solutions are intensively investigated to achieve a high performance human-robot collaboration (e.g., transparency, ergonomics, safety, etc.). However, the most of the investigated solutions involve high-cost hardware, complex design solutions and standard actuation. Moreover, state-of-the-art empowering controllers do not allow for online assistance regulation and do not embed advanced safety rules. In the presented work, an industrial exoskeleton with high payload ratio for lifting and transportation of heavy parts is proposed. A low-cost mechanical design solution is described, exploiting compliant actuation at the shoulder joint to increase safety in human-robot cooperation. A hierarchic model-based controller with embedded safety rules is then proposed (including the modeling of the compliant actuator) to actively assist the human while executing the task. An inner optimal controller is proposed for trajectory tracking, while an outer safety-based fuzzy logic controller is proposed to online deform the task trajectory on the basis of the human’s intention of motion. A gain scheduler is also designed to calculate the inner optimal control gains on the basis of the performed trajectory. Simulations have been performed in order to validate the performance of the proposed device, showing promising results. The prototype is under realization. Full article
(This article belongs to the Special Issue Advances in Italian Robotics)
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Open AccessArticle
Nonlinear Model Predictive Control for Mobile Robot Using Varying-Parameter Convergent Differential Neural Network
Robotics 2019, 8(3), 64; https://doi.org/10.3390/robotics8030064 - 31 Jul 2019
Cited by 2 | Viewed by 787
Abstract
The mobile robot kinematic model is a nonlinear affine system, which is constrained by velocity and acceleration limits. Therefore, the traditional control methods may not solve the tracking problem because of the physical constraint. In this paper, we present the nonlinear model predictive [...] Read more.
The mobile robot kinematic model is a nonlinear affine system, which is constrained by velocity and acceleration limits. Therefore, the traditional control methods may not solve the tracking problem because of the physical constraint. In this paper, we present the nonlinear model predictive control (NMPC) algorithm to track the desired trajectory based on neural-dynamic optimization. In the proposed algorithm, the NMPC scheme utilizes a new neural network named the varying-parameter convergent differential neural network (VPCDNN) which is a Hopfifield-neural network structure with respect to the differential equation theory to solve the quadratic programming (QP) problem. The new network structure converges to the global optimal solution and it is more efficient than traditional numerical methods. In the simulation, we verify that the proposed method is able to successfully track reference trajectories with a two-wheel mobile robot. The experimental validation has been conducted in simulation and the results show that the proposed method is able to precisely track the trajectory maintaining a high robustness based on the VPCDNN solver. Full article
(This article belongs to the Special Issue Robotics and Automation Engineering)
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Open AccessArticle
From Single 2D Depth Image to Gripper 6D Pose Estimation: A Fast and Robust Algorithm for Grabbing Objects in Cluttered Scenes
Robotics 2019, 8(3), 63; https://doi.org/10.3390/robotics8030063 - 30 Jul 2019
Viewed by 793
Abstract
In this paper, we investigate the problem of grasping previously unseen objects in unstructured environments which are cluttered with multiple objects. Object geometry, reachability, and force-closure analysis are considered to address this problem. A framework is proposed for grasping unknown objects by localizing [...] Read more.
In this paper, we investigate the problem of grasping previously unseen objects in unstructured environments which are cluttered with multiple objects. Object geometry, reachability, and force-closure analysis are considered to address this problem. A framework is proposed for grasping unknown objects by localizing contact regions on the contours formed by a set of depth edges generated from a single-view 2D depth image. Specifically, contact regions are determined based on edge geometric features derived from analysis of the depth map data. Finally, the performance of the approach is successfully validated by applying it to scenes with both single and multiple objects, in both simulation and experiments. Using sequential processing in MATLAB running on a 4th-generation Intel Core Desktop, simulation results with the benchmark Object Segmentation Database show that the algorithm takes 281 ms on average to generate the 6D robot pose needed to attach with a pair of viable grasping edges that satisfy reachability and force-closure conditions. Experimental results in the Assistive Robotics Laboratory at UCF using a Kinect One sensor and a Baxter manipulator outfitted with a standard parallel gripper showcase the feasibility of the approach in grasping previously unseen objects from uncontrived multi-object settings. Full article
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Open AccessArticle
FumeBot: A Deep Convolutional Neural Network Controlled Robot
Robotics 2019, 8(3), 62; https://doi.org/10.3390/robotics8030062 - 29 Jul 2019
Viewed by 862
Abstract
This paper describes the development of a convolutional neural network for the control of a home monitoring robot (FumeBot). The robot is fitted with a Raspberry Pi for on board control and a Raspberry Pi camera is used as the data feed for [...] Read more.
This paper describes the development of a convolutional neural network for the control of a home monitoring robot (FumeBot). The robot is fitted with a Raspberry Pi for on board control and a Raspberry Pi camera is used as the data feed for the neural network. A wireless connection between the robot and a graphical user interface running on a laptop allows for the diagnostics and development of the neural network. The neural network, running on the laptop, was trained using a supervised training method. The robot was put through a series of obstacle courses to test its robustness, with the tests demonstrating that the controller has learned to navigate the obstacles to a reasonable level. The main problem identified in this work was that the neural controller did not have memory of past actions it took and a past state of the world resulting in obstacle collisions. Options to rectify this issue are suggested. Full article
(This article belongs to the Section Robotics & Automation)
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Open AccessArticle
A Sensor-Network-Supported Mobile-Agent-Search Strategy for Wilderness Rescue
Robotics 2019, 8(3), 61; https://doi.org/10.3390/robotics8030061 - 24 Jul 2019
Viewed by 852
Abstract
Mobile target search is a problem pertinent to a variety of applications, including wilderness search and rescue. This paper proposes a hybrid approach for target search utilizing a team of mobile agents supported by a network of static sensors. The approach is novel [...] Read more.
Mobile target search is a problem pertinent to a variety of applications, including wilderness search and rescue. This paper proposes a hybrid approach for target search utilizing a team of mobile agents supported by a network of static sensors. The approach is novel in that the mobile agents deploy the sensors at optimized times and locations while they themselves travel along their respective optimized search trajectories. In the proposed approach, mobile-agent trajectories are first planned to maximize the likelihood of target detection. The deployment of the static-sensor network is subsequently planned. Namely, deployment locations and times are optimized while being constrained by the already planned mobile-agent trajectories. The latter optimization problem, as formulated and solved herein, aims to minimize an overall network-deployment error. This overall error comprises three main components, each quantifying a deviation from one of three main objectives the network aims to achieve: (i) maintaining directional unbiasedness in target-motion consideration, (ii) maintaining unbiasedness in temporal search-effort distribution, and, (iii) maximizing the likelihood of target detection. We solve this unique optimization problem using an iterative heuristic-based algorithm with random starts. The proposed hybrid search strategy was validated through the extensive simulations presented in this paper. Furthermore, its performance was evaluated with respect to an alternative hybrid search strategy, where it either outperformed or performed comparably depending on the search resources available. Full article
(This article belongs to the Section Robotics & Automation)
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Open AccessArticle
Impermeable and Compliant: SIBS as a Promising Encapsulant for Ionically Electroactive Devices
Robotics 2019, 8(3), 60; https://doi.org/10.3390/robotics8030060 - 24 Jul 2019
Viewed by 811
Abstract
Metals and glass are excellent for containing electrolytes and liquids in general, but their rigid mechanics limits their application for mechanically active ionic actuators or flexible/ stretchable electrochemical devices such as batteries and supercapacitors. In this study, we evaluate the performance of spray-coated [...] Read more.
Metals and glass are excellent for containing electrolytes and liquids in general, but their rigid mechanics limits their application for mechanically active ionic actuators or flexible/ stretchable electrochemical devices such as batteries and supercapacitors. In this study, we evaluate the performance of spray-coated poly (styrene-block-isobutylene-block-styrene) (SIBS) as a stretchable encapsulant, which suggests that it offers a better combination of compliance and impermeability than any other barrier. We examined the drying time of 360-µm thick encapsulated tri-layer conducting polymer (CP) actuators, comprised of poly(3,4-Ethylenedioxythiophene) (PEDOT) as the CP electrode and an interpenetrated polymer network of polyethylene oxide (PEO) and nitrile butadiene rubber (NBR) as the separator layer, which operates with a 1 M solution of Lithium bis(trifluoromethanesulfonyl)imide (Li+TFSI) in propylene carbonate (PC). A 100-µm thick SIBS encapsulation layer is anticipated to help these devices to retain 80% of stored PC for more than 1000 times longer compared to when there is no encapsulation (from less than 0.5 days to over 1.5 years). This low permeability combined with the low Young’s modulus of the SIBS film, its biocompatibility, biostability, and FDA approval, as well as ease of fabrication, make this thermoplastic elastomer a promising candidate as an encapsulant for flexible ionic devices such as flexible batteries and supercapacitors, ionic-electrode capacitive sensors, and ionically electroactive actuators. This paves the way for using these devices in implantable and in vivo applications. Full article
(This article belongs to the Special Issue Soft Machines: Integrating Sensing, Actuation and Computation)
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Open AccessArticle
Fault Diagnosis for UAV Blades Using Artificial Neural Network
Robotics 2019, 8(3), 59; https://doi.org/10.3390/robotics8030059 - 20 Jul 2019
Viewed by 995
Abstract
In recent years, unmanned aerial vehicles (UAVs) have been used in several fields including, for example, archaeology, cargo transport, conservation, healthcare, filmmaking, hobbies and recreational use. UAVs are aircraft characterized by the absence of a human pilot on board. The extensive use of [...] Read more.
In recent years, unmanned aerial vehicles (UAVs) have been used in several fields including, for example, archaeology, cargo transport, conservation, healthcare, filmmaking, hobbies and recreational use. UAVs are aircraft characterized by the absence of a human pilot on board. The extensive use of these devices has highlighted maintenance problems with regard to the propellers, which represent the source of propulsion of the aircraft. A defect in the propellers of a drone can cause the aircraft to fall to the ground and its consequent destruction, and it also constitutes a safety problem for objects and people that are in the range of action of the aircraft. In this study, the measurements of the noise emitted by a UAV were used to build a classification model to detect unbalanced blades in a UAV propeller. To simulate the fault condition, two strips of paper tape were applied to the upper surface of a blade. The paper tape created a substantial modification of the aerodynamics of the blade, and this modification characterized the noise produced by the blade in its rotation. Then, a model based on artificial neural network algorithms was built to detect unbalanced blades in a UAV propeller. This model showed high accuracy (0.9763), indicating a high number of correct detections and suggests the adoption of this tool to verify the operating conditions of a UAV. The test must be performed indoors; from the measurements of the noise produced by the UAV it is possible to identify an imbalance in the propeller blade. Full article
(This article belongs to the Special Issue Fault Diagnosis and Fault-Tolerant Control in Robotic Systems)
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Open AccessArticle
Online Strategy Clustering Based on Action Sequences in RoboCupSoccer Small Size League
Robotics 2019, 8(3), 58; https://doi.org/10.3390/robotics8030058 - 19 Jul 2019
Viewed by 827
Abstract
This paper addresses a strategy learning problem in the RoboCupSoccer Small Size League (SSL). We propose a novel method based on action sequences to cluster an opponent’s strategies online. Our proposed method is composed of the following three steps: (1) extracting typical actions [...] Read more.
This paper addresses a strategy learning problem in the RoboCupSoccer Small Size League (SSL). We propose a novel method based on action sequences to cluster an opponent’s strategies online. Our proposed method is composed of the following three steps: (1) extracting typical actions from geometric data to make action sequences, (2) calculating the dissimilarity of the sequences, and (3) clustering the sequences by using the dissimilarity. This method can reduce the amount of data used in the clustering process; handling action sequences instead of geometric data as data-set makes it easier to search actions. As a result, the proposed clustering method is online feasible and also is applicable to countering an opponent’s strategy. The effectiveness of the proposed method was validated by experimental results. Full article
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Open AccessArticle
Rotational Workspace Expansion of a Planar CDPR with a Circular End-Effector Mechanism Allowing Passive Reconfiguration
Robotics 2019, 8(3), 57; https://doi.org/10.3390/robotics8030057 - 19 Jul 2019
Viewed by 864
Abstract
Cable-Driven Parallel Robots (CDPR) operate over a large positional workspace and a relatively large orientation workspace. In the present work, the expansion of the orientation Wrench Feasible Workspace (WFW) in a planar four-cable passive reconfigurable parallel robot with three degrees of freedom was [...] Read more.
Cable-Driven Parallel Robots (CDPR) operate over a large positional workspace and a relatively large orientation workspace. In the present work, the expansion of the orientation Wrench Feasible Workspace (WFW) in a planar four-cable passive reconfigurable parallel robot with three degrees of freedom was determined. To this end, we proposed a circular-geometry effector mechanism, whose structure allows automatic mobility of the two anchor points of the cables supporting the End Effector (EE). The WFW of the proposed circular structure robot was compared with that of a traditional robot with a rectangular geometry and fixed anchor points. Considering the feasible geometric and tension forces on the cables, the generated workspace volume of the robot was demonstrated in an analysis-by-intervals. The results were validated by simulating the orientation movements of the robot in ADAMS software and a real experimental test was developed for a hypothetical case. The proposed design significantly expanded the orientation workspace of the robot. The remaining limitation is the segment of the travel space in which the mobile connection points can slide. Overcoming this limitation would enable the maximum rotation of the EE. Full article
(This article belongs to the Section Industrial Robots)
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Open AccessFeature PaperArticle
FludoJelly: Experimental Study on Jellyfish-Like Soft Robot Enabled by Soft Pneumatic Composite (SPC)
Robotics 2019, 8(3), 56; https://doi.org/10.3390/robotics8030056 - 15 Jul 2019
Viewed by 1056
Abstract
Several bio-inspired underwater robots have been demonstrated in the last few years that can horizontally swim using different smart actuators. However, very few works have been presented on robots which can swim vertically, have a payload and resemble a jellyfish-like creature. In this [...] Read more.
Several bio-inspired underwater robots have been demonstrated in the last few years that can horizontally swim using different smart actuators. However, very few works have been presented on robots which can swim vertically, have a payload and resemble a jellyfish-like creature. In this work, we present the design, fabrication, and performance characterization of a new tethered robotic jellyfish, which is based on inflatable soft pneumatic composite (SPC) actuators. These soft actuators use compressed air to expand and contract, which help the robot to swim vertically in water. The soft actuators consist of elastomeric air chambers and very thin steel springs, which contribute to gaining faster motion of the biomimetic robot. A prototype of 220 mm in diameter and consisting of eight actuating units was fabricated and tested underwater in a fish tank. It reached a height of 400 mm within 2.5 s while carrying a dead weight of 100 g when tested at 70 psi (483 kPa) pressure. This high performance (160 mm/s on average speed) suggests that faster motion with a payload can be achieved by using SPC actuators. The inflatable structures help to flap the bell segments as well as in buoyancy effect for rapid vertical motion. The major achievement of this work is the ability to demonstrate a novel use of inflatable structures and biomimetic flapping wings for fast motion in water. The experimental and deduced data from this work can be used for the design of future small unmanned underwater vehicles (UUVs). This work adds a new robot to the design space of biomimetic jellyfish-like soft robots. Such kind of vehicle design might also be useful for transporting objects underwater effectively. Full article
(This article belongs to the Special Issue Advances in Underwater Robotics)
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Open AccessArticle
Realization of a Robot System That Plays “Darumasan-Ga-Koronda ” Game with Humans
Robotics 2019, 8(3), 55; https://doi.org/10.3390/robotics8030055 - 12 Jul 2019
Viewed by 1006
Abstract
In this paper, we describe the development of a robot that plays the “darumasan-ga- koronda” game with human players. It is a big challenge to develop a robot that can play with human players. We first observed the human–human game play and listed [...] Read more.
In this paper, we describe the development of a robot that plays the “darumasan-ga- koronda” game with human players. It is a big challenge to develop a robot that can play with human players. We first observed the human–human game play and listed the problems for a robot to play the game with human players. We pointed out the following six tasks: detect players, track the detected players, decide if players are freezing (the “out” judgment), move to the nearest player, touch the player, and move back to the original position. Then, we designed a robot that uses a laser range finder (LRF) to measure the players and a robot avatar to interact with the players. Then, we developed the components needed to play the game. In this paper, we describe the details of the development of the arm to touch the player, the “out” judgment, and a function to return to the origin after finishing the game. Then, we describe an experimental result of the evaluation of the total system, as well as the track record of the demonstrations in the events. Full article
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Open AccessReview
A Survey of Behavioral Models for Social Robots
Robotics 2019, 8(3), 54; https://doi.org/10.3390/robotics8030054 - 09 Jul 2019
Viewed by 973
Abstract
The cooperation between humans and robots is becoming increasingly important in our society. Consequently, there is a growing interest in the development of models that can enhance and enrich the interaction between humans and robots. A key challenge in the Human-Robot Interaction (HRI) [...] Read more.
The cooperation between humans and robots is becoming increasingly important in our society. Consequently, there is a growing interest in the development of models that can enhance and enrich the interaction between humans and robots. A key challenge in the Human-Robot Interaction (HRI) field is to provide robots with cognitive and affective capabilities, by developing architectures that let them establish empathetic relationships with users. Over the last several years, multiple models were proposed to face this open-challenge. This work provides a survey of the most relevant attempts/works. In details, it offers an overview of the architectures present in literature focusing on three specific aspects of HRI: the development of adaptive behavioral models, the design of cognitive architectures, and the ability to establish empathy with the user. The research was conducted within two databases: Scopus and Web of Science. Accurate exclusion criteria were applied to screen the 4916 articles found. At the end, 56 articles were selected. For each work, an evaluation of the model is made. Pros and cons of each work are detailed by analyzing the aspects that can be improved to establish an enjoyable interaction between robots and users. Full article
(This article belongs to the Special Issue Advances in Italian Robotics)
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Open AccessArticle
Press Start to Play: Classifying Multi-Robot Operators and Predicting Their Strategies through a Videogame
Robotics 2019, 8(3), 53; https://doi.org/10.3390/robotics8030053 - 09 Jul 2019
Viewed by 949
Abstract
One of the active challenges in multi-robot missions is related to managing operator workload and situational awareness. Currently, the operators are trained to use interfaces, but in the near future this can be turned inside out: the interfaces will adapt to operators so [...] Read more.
One of the active challenges in multi-robot missions is related to managing operator workload and situational awareness. Currently, the operators are trained to use interfaces, but in the near future this can be turned inside out: the interfaces will adapt to operators so as to facilitate their tasks. To this end, the interfaces should manage models of operators and adapt the information to their states and preferences. This work proposes a videogame-based approach to classify operator behavior and predict their actions in order to improve teleoperated multi-robot missions. First, groups of operators are generated according to their strategies by means of clustering algorithms. Second, the operators’ strategies are predicted, taking into account their models. Multiple information sources and modeling methods are used to determine the approach that maximizes the mission goal. The results demonstrate that predictions based on previous data from single operators increase the probability of success in teleoperated multi-robot missions by 19%, whereas predictions based on operator clusters increase this probability of success by 28%. Full article
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Open AccessArticle
Cooperative Optimization of UAVs Formation Visual Tracking
Robotics 2019, 8(3), 52; https://doi.org/10.3390/robotics8030052 - 07 Jul 2019
Viewed by 1026
Abstract
The use of unmanned vehicles to perform tiring, hazardous, repetitive tasks, is becoming a reality out of the academy laboratories, getting more and more interest for several application fields from the industrial, to the civil, to the military contexts. In particular, these technologies [...] Read more.
The use of unmanned vehicles to perform tiring, hazardous, repetitive tasks, is becoming a reality out of the academy laboratories, getting more and more interest for several application fields from the industrial, to the civil, to the military contexts. In particular, these technologies appear quite promising when they employ several low-cost resource-constrained vehicles leveraging their coordination to perform complex tasks with efficiency, flexibility, and adaptation that are superior to those of a single agent (even if more instrumented). In this work, we study one of said applications, namely the visual tracking of an evader (target) by means of a fleet of autonomous aerial vehicles, with the specific aim of focusing on the target so as to perform an accurate position estimation while concurrently allowing a wide coverage over the monitored area so as to limit the probability of losing the target itself. These clearly conflicting objectives call for an optimization approach that is here developed: by considering both aforementioned aspects and the cooperative capabilities of the fleet, the designed algorithm allows controling in real time the single fields of view so as to counteract evasion maneuvers and maximize an overall performance index. The proposed strategy is discussed and finally assessed through the realistic Gazebo-ROS simulation framework. Full article
(This article belongs to the Special Issue Navigation and Control of UAVs)
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