Special Issue "Kinematics and Robot Design I, KaRD2018"

A special issue of Robotics (ISSN 2218-6581).

Deadline for manuscript submissions: closed (15 September 2018) | Viewed by 80996

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A printed edition of this Special Issue is available here.

Special Issue Editor

Prof. Dr. Raffaele Di Gregorio
E-Mail Website
Guest Editor
Engineering Department, University of Ferrara, 44122 Ferrara, Italy
Interests: kinematics; biomechanics; robotics; parallel manipulators
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Kinematics enters many aspects of robot design. Type synthesis, dimensional synthesis, kinematic analysis, singularity analysis, workspace determination, performance measures, accuracy analysis, path planning and obstacle avoidance are only some of these. In addition, it is central when building dynamic models for simulation purposes.

Additionally, robotics is pervading many fields of social interest. For instance, healthcare with its robotized medical devices and rehabilitation devices needs studies both on human biomechanics and on mechanism synthesis, which involve kinematics.

Nowadays, a numerous scientific community is involved in such studies and, even though many conferences (ARK, CK, ASME MR, etc.) on robot and/or mechanism kinematics take place regularly, there is room for further initiatives. This open-source Special Issue with cheap publication costs wishes to provide a good opportunity for presenting research results that are immediately readable and usable by other researchers.

The Special Issue aims at collecting recent research on all the below-listed topics. Review papers are also welcome.

Topics of interest include (but are not limited to):

  • synthesis of mechanisms
  • theoretical and computational kinematics
  • robot modeling and simulation
  • kinematics in robot control
  • position analysis
  • mobility and singularity analysis
  • performance measures
  • accuracy analysis
  • path planning and obstacle avoidance
  • novel manipulator architectures
  • metamorphic mechanisms
  • compliant mechanism analysis and synthesis
  • micro/nanomanipulator design
  • origami-based robotics
  • medical and rehabilitation robotics
  • kinematics in biological systems, humanoid robots and humanoid subsystems

Prof. Dr. Raffaele Di Gregorio
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Robotics is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • mechanism synthesis
  • kinematic analysis
  • robot modeling and simulation
  • robot control
  • singularity analysis
  • performance measures
  • accuracy analysis
  • path planning
  • parallel manipulator
  • serial manipulator
  • robot design
  • compliant mechanism
  • micro/nanomanipulator
  • origami-based robotics
  • medical and rehabilitation robotics
  • biomechanics

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Published Papers (14 papers)

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Article
Adaptive Balancing of Robots and Mechatronic Systems
Robotics 2018, 7(4), 68; https://doi.org/10.3390/robotics7040068 - 07 Nov 2018
Cited by 7 | Viewed by 5615
Abstract
Present paper is dealing with the adaptive static balancing of robot or other mechatronic arms that are rocking in vertical plane and whose static loads are variable, by using counterweights and springs. Some simple passive and approximate solutions are proposed, and an example [...] Read more.
Present paper is dealing with the adaptive static balancing of robot or other mechatronic arms that are rocking in vertical plane and whose static loads are variable, by using counterweights and springs. Some simple passive and approximate solutions are proposed, and an example is shown. The results show that a very simple passive solution which is using for gravity compensation a simple translational counterweight (that could be for example the actuating motor itself) articulated by one single bar leads to very good results in case of approximate balancing when the payload has a known variation. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Design and Implementation of a Dual-Axis Tilting Quadcopter
Robotics 2018, 7(4), 65; https://doi.org/10.3390/robotics7040065 - 20 Oct 2018
Cited by 28 | Viewed by 8303
Abstract
Standard quadcopters are popular largely because of their mechanical simplicity relative to other hovering aircraft, low cost and minimum operator involvement. However, this simplicity imposes fundamental limits on the types of maneuvers possible due to its under-actuation. The dexterity and fault tolerance required [...] Read more.
Standard quadcopters are popular largely because of their mechanical simplicity relative to other hovering aircraft, low cost and minimum operator involvement. However, this simplicity imposes fundamental limits on the types of maneuvers possible due to its under-actuation. The dexterity and fault tolerance required for flying in limited spaces like forests and industrial infrastructures dictate the use of a bespoke dual-tilting quadcopter that can launch vertically, performs autonomous flight between adjacent obstacles and is even capable of flying in the event of the failure of one or two motors. This paper proposes an actuation concept to enhance the performance characteristics of the conventional under-actuated quadcopter. The practical formation of this concept is followed by the design, modeling, simulation and prototyping of a dual-axis tilting quadcopter. Outdoor flight tests using tilting rotors, to follow a trajectory containing adjacent obstacles, were conducted in order to compare the flight of conventional quadcopter with the proposed over-actuated vehicle. The results show that the quadcopter with tilting rotors provides more agility and mobility to the vehicle especially in narrow indoor and outdoor infrastructures. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Spacecraft Robot Kinematics Using Dual Quaternions
Robotics 2018, 7(4), 64; https://doi.org/10.3390/robotics7040064 - 12 Oct 2018
Cited by 13 | Viewed by 6070
Abstract
In recent years, there has been a growing interest in servicing orbiting satellites. In most cases, in-orbit servicing relies on the use of spacecraft-mounted robotic manipulators to carry out complicated mission objectives. Dual quaternions, a mathematical tool to conveniently represent pose, has recently [...] Read more.
In recent years, there has been a growing interest in servicing orbiting satellites. In most cases, in-orbit servicing relies on the use of spacecraft-mounted robotic manipulators to carry out complicated mission objectives. Dual quaternions, a mathematical tool to conveniently represent pose, has recently been adopted within the space industry to tackle complex control problems during the stages of proximity operations and rendezvous, as well as for the dynamic modeling of robotic arms mounted on a spacecraft. The objective of this paper is to bridge the gap in the use of dual quaternions that exists between the fields of spacecraft control and fixed-base robotic manipulation. In particular, we will cast commonly used tools in the field of robotics as dual quaternion expressions, such as the Denavit-Hartenberg parameterization, or the product of exponentials formula. Additionally, we provide, via examples, a study of the kinematics of different serial manipulator configurations, building up to the case of a completely free-floating robotic system. We provide expressions for the dual velocities of the different types of joints that commonly arise in industrial robots, and we end by providing a collection of results that cast convex constraints commonly encountered by space robots during proximity operations in terms of dual quaternions. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Non-Linear Lumped-Parameter Modeling of Planar Multi-Link Manipulators with Highly Flexible Arms
Robotics 2018, 7(4), 60; https://doi.org/10.3390/robotics7040060 - 25 Sep 2018
Cited by 32 | Viewed by 5781
Abstract
The problem of the trajectory-tracking and vibration control of highly flexible planar multi-links robot arms is investigated. We discretize the links according to the Hencky bar-chain model, which is an application of the lumped parameters techniques. In this approach, each link is considered [...] Read more.
The problem of the trajectory-tracking and vibration control of highly flexible planar multi-links robot arms is investigated. We discretize the links according to the Hencky bar-chain model, which is an application of the lumped parameters techniques. In this approach, each link is considered as a kinematic chain of rigid bodies, and suitable springs are added in order to model bending resistance. The control strategy employed is based on an optimal input pre-shaping and a feedback of the joint angles to treat the effects of undesired disturbances. Some numerical examples are given to show the potentialities of the proposed control, and a comparison with a standard collocated Proportional-Derivative (PD) control strategy is performed. In particular, we study the cases of a linear and a parabolic trajectory with a polynomial time law chosen to minimize the onset of possible vibrations. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Kinematics Analysis of a Class of Spherical PKMs by Projective Angles
Robotics 2018, 7(4), 59; https://doi.org/10.3390/robotics7040059 - 20 Sep 2018
Cited by 2 | Viewed by 4093
Abstract
This paper presents the kinematics analysis of a class of spherical PKMs Parallel Kinematics Machines exploiting a novel approach. The analysis takes advantage of the properties of the projective angles, which are a set of angular conventions of which their properties have only [...] Read more.
This paper presents the kinematics analysis of a class of spherical PKMs Parallel Kinematics Machines exploiting a novel approach. The analysis takes advantage of the properties of the projective angles, which are a set of angular conventions of which their properties have only recently been presented. Direct, inverse kinematics and singular configurations are discussed. The analysis, which results in the solution of easy equations, is developed at position, velocity and acceleration level. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Performance-Based Design of the CRS-RRC Schoenflies-Motion Generator
Robotics 2018, 7(3), 55; https://doi.org/10.3390/robotics7030055 - 15 Sep 2018
Cited by 4 | Viewed by 4204
Abstract
Rigid-body displacements obtained by combining spatial translations and rotations around axes whose direction is fixed in the space are named Shoenflies’ motions. They constitute a 4-dimensional (4-D) subgroup, named Shoenflies’ subgroup, of the 6-D displacement group. Since the set of rotation-axis’ directions is [...] Read more.
Rigid-body displacements obtained by combining spatial translations and rotations around axes whose direction is fixed in the space are named Shoenflies’ motions. They constitute a 4-dimensional (4-D) subgroup, named Shoenflies’ subgroup, of the 6-D displacement group. Since the set of rotation-axis’ directions is a bi-dimensional space, the set of Shoenflies’ subgroups is a bi-dimensional space, too. Many industrial manipulations (e.g., pick-and-place on a conveyor belt) require displacements that belong to only one Schoenflies’ subgroup and can be accomplished by particular 4-degrees-of-freedom (4-DOF) manipulators (Shoenflies-motion generators (SMGs)). The first author has recently proposed a novel parallel SMG of type CRS-RRC1. Such SMG features a single-loop architecture with actuators on the base and a simple decoupled kinematics. Here, firstly, an organic review of the previous results on this SMG is presented; then, its design is addressed by considering its kinetostatic performances. The adopted design procedure optimizes two objective functions, one (global conditioning index (GCI)) that measures the global performance and the other (CImin) that evaluates the worst local performance in the useful workspace. The results of this optimization procedure are the geometric parameters’ values that make the studied SMG have performances comparable with those of commercial SMGs. In addition, a realistic 3D model that solves all the manufacturing doubts with simple and cheap solutions is presented. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Design of a Lockable Spherical Joint for a Reconfigurable 3-URU Parallel Platform
Robotics 2018, 7(3), 42; https://doi.org/10.3390/robotics7030042 - 02 Aug 2018
Cited by 6 | Viewed by 4662
Abstract
This article deals with the functional and preliminary design of a reconfigurable joint for robotic applications. Such mechanism is a key element for a class of lower mobility parallel manipulators, allowing a local reconfiguration of the kinematic chain that enables a change in [...] Read more.
This article deals with the functional and preliminary design of a reconfigurable joint for robotic applications. Such mechanism is a key element for a class of lower mobility parallel manipulators, allowing a local reconfiguration of the kinematic chain that enables a change in platform’s mobility. The mechanism can be integrated in the kinematic structure of a 3-URU manipulator, which shall accordingly gain the ability to change mobility from pure translation to pure rotation. As a matter of fact, special kinematics conditions must be met for the accomplishment of this task. Such peculiar requirements are described and properly exploited for the design of an effective reconfigurable mechanism. A detailed description of the joint operational principle is provided, also showing how to design it when is physically located at the fixed base of the manipulator. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Viability and Feasibility of Constrained Kinematic Control of Manipulators
Robotics 2018, 7(3), 41; https://doi.org/10.3390/robotics7030041 - 23 Jul 2018
Cited by 6 | Viewed by 4383
Abstract
Recent advances in planning and control of robot manipulators make an increasing use of optimization-based techniques, such as model predictive control. In this framework, ensuring the feasibility of the online optimal control problem is a key issue. In the case of manipulators with [...] Read more.
Recent advances in planning and control of robot manipulators make an increasing use of optimization-based techniques, such as model predictive control. In this framework, ensuring the feasibility of the online optimal control problem is a key issue. In the case of manipulators with bounded joint positions, velocities, and accelerations, feasibility can be guaranteed by limiting the set of admissible velocities and positions to a viable set. However, this results in the imposition of nonlinear optimization constraints. In this paper, we analyze the feasibility of the optimal control problem and we propose a method to construct a viable convex polyhedral that ensures feasibility of the optimal control problem by means of a given number of linear constraints. Experimental and numerical results on an industrial manipulator show the validity of the proposed approach. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Fully Mechatronical Design of an HIL System for Floating Devices
Robotics 2018, 7(3), 39; https://doi.org/10.3390/robotics7030039 - 20 Jul 2018
Cited by 5 | Viewed by 4970
Abstract
Recent simulation developments in Computational Fluid Dynamics (CFD) have widely increased the knowledge of fluid–structure interaction. This has been particularly effective in the research field of floating bodies such as offshore wind turbines and sailboats, where air and sea are involved. Nevertheless, the [...] Read more.
Recent simulation developments in Computational Fluid Dynamics (CFD) have widely increased the knowledge of fluid–structure interaction. This has been particularly effective in the research field of floating bodies such as offshore wind turbines and sailboats, where air and sea are involved. Nevertheless, the models used in the CFD analysis require several experimental parameters in order to be completely calibrated and capable of accurately predicting the physical behaviour of the simulated system. To make up for the lack of experimental data, usually wind tunnel and ocean basin tests are carried out. This paper presents a fully mechatronical design of an Hardware In the Loop (HIL) system capable of simulating the effects of the sea on a physical scaled model positioned in a wind tunnel. This system allows one to obtain all the required information to characterize a model subject, and at the same time to assess the effects of the interaction between wind and sea waves. The focus of this work is on a complete overview of the procedural steps to be followed in order to reach a predefined performance. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Optimal Kinematic Design of a 6-UCU Kind Gough-Stewart Platform with a Guaranteed Given Accuracy
Robotics 2018, 7(2), 30; https://doi.org/10.3390/robotics7020030 - 18 Jun 2018
Cited by 2 | Viewed by 7384
Abstract
The 6-UCU (U-universal joint; C-cylinder joint) kind Gough-Stewart platform is extensively employed in motion simulators due to its high accuracy, large payload, and high-speed capability. However, because of the manufacturing and assembling errors, the real geometry may be different from the nominal one. [...] Read more.
The 6-UCU (U-universal joint; C-cylinder joint) kind Gough-Stewart platform is extensively employed in motion simulators due to its high accuracy, large payload, and high-speed capability. However, because of the manufacturing and assembling errors, the real geometry may be different from the nominal one. In the design process of the high-accuracy Gough-Stewart platform, one needs to consider these errors. The purpose of this paper is to propose an optimal design method for the 6-UCU kind Gough-Stewart platform with a guaranteed given accuracy. Accuracy analysis of the 6-UCU kind Gough-Stewart platform is presented by considering the limb length errors and joint position errors. An optimal design method is proposed by using a multi-objective evolutionary algorithm, the non-dominated sorting genetic algorithm II (NSGA-II). A set of Pareto-optimal parameters was found by applying the proposed optimal design method. An engineering design case was studied to verify the effectiveness of the proposed method. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Hexapods with Plane-Symmetric Self-Motions
Robotics 2018, 7(2), 27; https://doi.org/10.3390/robotics7020027 - 08 Jun 2018
Viewed by 4119
Abstract
A hexapod is a parallel manipulator where the platform is linked with the base by six legs, which are anchored via spherical joints. In general, such a mechanical device is rigid for fixed leg lengths, but, under particular conditions, it can perform a [...] Read more.
A hexapod is a parallel manipulator where the platform is linked with the base by six legs, which are anchored via spherical joints. In general, such a mechanical device is rigid for fixed leg lengths, but, under particular conditions, it can perform a so-called self-motion. In this paper, we determine all hexapods possessing self-motions of a special type. The motions under consideration are so-called plane-symmetric ones, which are the straight forward spatial counterpart of planar/spherical symmetric rollings. The full classification of hexapods with plane-symmetric self-motions is achieved by formulating the problem in terms of algebraic geometry by means of Study parameters. It turns out that besides the planar/spherical symmetric rollings with circular paths and two trivial cases (butterfly self-motion and two-dimensional spherical self-motion), only one further solution exists, which is the so-called Duporcq hexapod. This manipulator, which is studied in detail in the last part of the paper, may be of interest for the design of deployable structures due to its kinematotropic behavior and total flat branching singularities. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Motion Investigation of a Snake Robot with Different Scale Geometry and Coefficient of Friction
Robotics 2018, 7(2), 18; https://doi.org/10.3390/robotics7020018 - 28 Apr 2018
Cited by 7 | Viewed by 5937
Abstract
Most snakes in nature have scales at their ventral sides. The anisotropic frictional coefficient of the ventral side of the snakes, as well as snake robots, is considered to be responsible for their serpentine kind of locomotion. However, little work has been done [...] Read more.
Most snakes in nature have scales at their ventral sides. The anisotropic frictional coefficient of the ventral side of the snakes, as well as snake robots, is considered to be responsible for their serpentine kind of locomotion. However, little work has been done on snake scales so far to make any guidelines for designing snake robots. This paper presents an experimental investigation on the effects of artificial scale geometry on the motion of snake robots that move in a serpentine manner. The motion of a snake robot equipped with artificial scales with different geometries was recorded using a Kinect camera under different speeds of the actuating motors attached to the links of the robot. The results of the investigation showed that the portion of the scales along the central line of the robot did not contributed to the locomotion of the robot, rather, it is the parts of the scales along the lateral edges of the robot that contributed to the motion. It was also found that the lower frictional ratio at low slithering speeds made the snake robot motion unpredictable. The scales with ridges along the direction of the snake body gave better and more stable motion. However, to get the peg effect, the scales needed to have a very high lateral to forward friction ratio, otherwise, significant side slipping occurred, resulting in unpredictable motion. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Article
Cable Robot Performance Evaluation by Wrench Exertion Capability
Robotics 2018, 7(2), 15; https://doi.org/10.3390/robotics7020015 - 27 Mar 2018
Cited by 22 | Viewed by 5812
Abstract
Although cable driven robots are a type of parallel manipulators, the evaluation of their performances cannot be carried out using the performance indices already developed for parallel robots with rigid links. This is an obvious consequence of the peculiar features of flexible cables—a [...] Read more.
Although cable driven robots are a type of parallel manipulators, the evaluation of their performances cannot be carried out using the performance indices already developed for parallel robots with rigid links. This is an obvious consequence of the peculiar features of flexible cables—a cable can only exert a tensile and limited force in the direction of the cable itself. A comprehensive performance evaluation can certainly be attained by computing the maximum force (or torque) that can be exerted by the cables on the moving platform along a specific (or any) direction within the whole workspace. This is the idea behind the index—called the Wrench Exertion Capability (WEC)—which can be employed to evaluate the performance of any cable robot topology and is characterized by an efficient and simple formulation based on linear programming. By significantly improving a preliminary computation method for the WEC, this paper proposes an ultimate formulation suitable for any cable robot topology. Several numerical investigations on planar and spatial cable robots are presented to give evidence of the WEC usefulness, comparisons with popular performance indices are also provided. Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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Technical Note
Nominal Stiffness of GT-2 Rubber-Fiberglass Timing Belts for Dynamic System Modeling and Design
Robotics 2018, 7(4), 75; https://doi.org/10.3390/robotics7040075 - 21 Nov 2018
Viewed by 8079
Abstract
GT-style rubber-fiberglass (RF) timing belts are designed to effectively transfer rotational motion from pulleys to linear motion in robots, small machines, and other important mechatronic systems. One of the characteristics of belts under this type of loading condition is that the length between [...] Read more.
GT-style rubber-fiberglass (RF) timing belts are designed to effectively transfer rotational motion from pulleys to linear motion in robots, small machines, and other important mechatronic systems. One of the characteristics of belts under this type of loading condition is that the length between load and pulleys changes during operation, thereby changing their effective stiffness. It has been shown that the effective stiffness of such a belt is a function of a “nominal stiffness” and the real-time belt section lengths. However, this nominal stiffness is not necessarily constant; it is common to assume linear proportional stiffness, but this often results in system modeling error. This technical note describes a brief study where the nominal stiffness of two lengths ( 400 m m and 760 m m ) of GT-2 RF timing belt was tested up to breaking point; regression analysis was performed on the results to best model the observed stiffness. The experiments were performed three times, providing a total of six stiffness curves. It was found that cubic regression mod els ( R 2 > 0.999 ) were the best fit, but that quadratic and linear models still provided acceptable representations of the whole dataset with R 2 values above 0.940 . Full article
(This article belongs to the Special Issue Kinematics and Robot Design I, KaRD2018)
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