Optimal Design of a Six-Bar Linkage with One Degree of Freedom for an Anthropomorphic Three-Jointed Finger Mechanism

This research concerns the design of a three-jointed, anthropomorphic, finger mechanism for use as a prosthesis or robotic end-effector. Based on a study of finger configurations for the human hand, a six-bar linkage with one degree of freedom is proposed. A model of the fingertip displacement of the mechanism is derived by a vector analysis approach. The effects of joint friction on the transmission efficiency are analysed. By measuring the joint positions of a human finger, a mathematical model of the pinching and holding configurations are developed. Optimal parameters for the finger mechanism are obtained by non-linear programming based on an objective functional involving motion posture and locus, transmission efficiency and weight subject to geometric and bionic constraints. Simulation results indicate that the mechanism is useful for a variety of prosthetic and robotic applications.

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Optimal Design of a Six-Bar Linkage for an Anthropomorphic Three-Jointed Finger Mechanism

22nd Biennial Mechanisms Conference: Robotics, Spatial Mechanisms, and Mechanical Systems ◽

10.1115/detc1992-0227 ◽

1992 ◽

Author(s):

Jichuan Zhang ◽

Gongliang Guo ◽

William A. Gruver

Keyword(s):

Mathematical Model ◽

Nonlinear Programming ◽

Optimal Design ◽

Transmission Efficiency ◽

Degree Of Freedom ◽

Optimal Parameters ◽

Joint Friction ◽

Robotic Devices ◽

End Effectors ◽

Human Finger

Abstract We treat the design of a three-jointed, anthropomorphic, finger mechanism for prostheses and robotic end-effectors. Based on the study of configurations for the human finger, we propose a six-bar linkage with one degree of freedom for the finger mechanism. A model of the fingertip displacement of the mechanism is derived by a vector analysis approach. We study the effects of joint friction on the transmission efficiency. By measuring the joint positions of a human finger, we develop a mathematical model of the pinching and holding configurations for the human finger. Optimal parameters for the finger mechanism are obtained by nonlinear programming based on motion posture, locus, transmission efficiency, and weight subject to geometric and bionic constraints. Simulations indicate that the mechanism is useful in a variety of prosthetic and robotic devices.

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About an Experimental Approach Used to Determine the Kinematics of the Human Finger Movement

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.166-167.45 ◽

2010 ◽

Vol 166-167 ◽

pp. 45-50 ◽

Cited By ~ 12

Author(s):

Cosmin Berceanu ◽

Daniela Tarniţă ◽

Dumitru Filip

Keyword(s):

Video Processing ◽

Experimental Approach ◽

Color Temperature ◽

Human Hand ◽

Finger Movement ◽

Video Capture ◽

Kinematic Parameters ◽

End Effector ◽

Human Finger ◽

High Degree

Nowadays the robotic or prosthetic artificial hands strive to achieve a high degree of anthropomorphism, a concept which expresses the capability of a robotic end-effector to mimic the human hand, partly or totally, as far as shape, size, consistency, and general aspect (including color, temperature, and so on). This paper proposes a new experimental approach regarding the kinematics of the human finger movement. By using video capture of a particular finger movement and dedicated video processing software we have determined the laws of variation for the main joints in the human finger. Therefore, the experimental method presented in detail in this paper is useful to corroborate the kinematic parameters (displacements, velocities and accelerations, linear or rotary) of an artificial robotic finger movement with those of the human finger movement.

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Analytical Computation of the Actuator and Cartesian Workspace Boundaries for a Planar 2-Degree-of-Freedom Translational Tensegrity Mechanism

Journal of Mechanisms and Robotics ◽

10.1115/1.4005335 ◽

2012 ◽

Vol 4 (1) ◽

Cited By ~ 11

Author(s):

Samuel Chen ◽

Marc Arsenault

Keyword(s):

Translational Motion ◽

Inverse Kinematic ◽

Degree Of Freedom ◽

End Effector ◽

Optimal Mechanism ◽

High Acceleration ◽

Pick And Place ◽

Actuation Scheme ◽

Two Degree Of Freedom ◽

Robotic Applications

Tensegrity mechanisms are interesting candidates for high-acceleration robotic applications since their use of cables allows for a reduction in the weight and inertia of their mobile parts. In this work, a planar two-degree-of-freedom translational tensegrity mechanism that could be used for pick and place applications is introduced. The mechanism uses a strategic actuation scheme to generate the translational motion as well as to ensure that the cables remain taut at all times. Analytical solutions to the direct and inverse kinematic problems are developed, and the mechanism’s workspace boundaries are computed in both the actuator and Cartesian spaces. The influence of the mechanism’s geometry on the size and shape of the Cartesian workspace are then studied. Based on workspace size only, it is found that the optimal mechanism geometry corresponds to a relatively large ratio between the length of the struts and the width of the base and end-effector.

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Three-Degree-of-Freedom Parallel Robot Arm

Dynamic Systems and Control, Parts A and B ◽

10.1115/imece2006-14825 ◽

2006 ◽

Author(s):

Martin Hosek ◽

Michael Valasek ◽

Jairo Moura

Keyword(s):

Parallel Robot ◽

Degree Of Freedom ◽

Motion Path ◽

Angular Orientation ◽

Robot Arm ◽

Flat Panel Display ◽

End Effector ◽

Cluster Tools ◽

Manufacturing Applications ◽

Three Degree Of Freedom

This paper presents single- and dual-end-effector configurations of a planar three-degree of freedom parallel robot arm designed for automated pick-place operations in vacuum cluster tools for semiconductor and flat-panel-display manufacturing applications. The basic single end-effector configuration of the arm consists of a pivoting base platform, two elbow platforms and a wrist platform, which are connected through two symmetric pairs of parallelogram mechanisms. The wrist platform carries an end-effector, the position and angular orientation of which can be controlled independently by three motors located at the base of the robot. The joints and links of the mechanism are arranged in a unique geometric configuration which provides a sufficient range of motion for typical vacuum cluster tools. The geometric properties of the mechanism are further optimized for a given motion path of the robot. In addition to the basic symmetric single end-effector configuration, an asymmetric costeffective version of the mechanism is derived, and two dual-end-effector alternatives for improved throughput performance are described. In contrast to prior attempts to control angular orientation of the end-effector(s) of the conventional arms employed currently in vacuum cluster tools, all of the motors that drive the arm can be located at the stationary base of the robot with no need for joint actuators carried by the arm or complicated belt arrangements running through the arm. As a result, the motors do not contribute to the mass and inertia properties of the moving parts of the arm, no power and signal wires through the arm are necessary, the reliability and maintenance aspects of operation are improved, and the level of undesirable particle generation is reduced. This is particularly beneficial for high-throughput applications in vacuum and particlesensitive environments.

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Force Capabilities of Two-Degree-of-Freedom Serial Robots Equipped With Passive Isotropic Force Limiters

Volume 5B: 39th Mechanisms and Robotics Conference ◽

10.1115/detc2015-46486 ◽

2015 ◽

Author(s):

Meiying Zhang ◽

Thierry Laliberté ◽

Clément Gosselin

Keyword(s):

Human Robot Interaction ◽

Contact Forces ◽

Degree Of Freedom ◽

Practical Implementation ◽

Robot Interaction ◽

End Effector ◽

Serial Robots ◽

Serial Robot ◽

Maximum Contact ◽

Two Degree Of Freedom

This paper proposes the use of passive force and torque limiting devices to bound the maximum forces that can be applied at the end-effector or along the links of a robot, thereby ensuring the safety of human-robot interaction. Planar isotropic force limiting modules are proposed and used to analyze the force capabilities of a two-degree-of-freedom planar serial robot. The force capabilities at the end-effector are first analyzed. It is shown that, using isotropic force limiting modules, the performance to safety index remains excellent for all configurations of the robot. The maximum contact forces along the links of the robot are then analyzed. Force and torque limiters are distributed along the structure of the robot in order to ensure that the forces applied at any point of contact along the links are bounded. A power analysis is then presented in order to support the results. Finally, examples of mechanical designs of force/torque limiters are shown to illustrate a possible practical implementation of the concept.

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Seven-Position Synthesis of a Spatial Eight-Bar Linkage by Constraining a TRS Serial Chain

Volume 7: 33rd Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2009-87366 ◽

2009 ◽

Cited By ~ 1

Author(s):

Gim Song Soh ◽

J. Michael McCarthy

Keyword(s):

Degree Of Freedom ◽

Upper Arm ◽

End Effector ◽

Serial Chain ◽

Position Synthesis ◽

Two Degree Of Freedom ◽

Puma Robot

In this paper, we use seven-position synthesis to add four TS constraints to a TRS serial chain robot and obtain a two degree-of-freedom spatial eight-bar linkage. The TRS chain is an elbow manipulator, similar to a PUMA robot. We synthesize a TS dyad to connect the base of the robot to its forearm, and then we synthesize three TS dyads that connect the upper arm of the robot to its end-effector. The result is a two degree-of-freedom spatial eight-bar linkage that moves through seven prescribed positions. It consists of a TRST loop supporting a 3TS-RS platform, which we denote as a TS-TRS-3TS spatial linkage. We formulate and solve the design equations for the TS dyads, and analyze the resulting eight-bar linkage. An example demonstrates our results.

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Increasing ABB FlexPicker Robot’s Degree of Freedom (DOF) using Flexible End Effector

MATEC Web of Conferences ◽

10.1051/matecconf/20167801056 ◽

2016 ◽

Vol 78 ◽

pp. 01056

Author(s):

M. H. Nordin ◽

K. Selvaraju ◽

M. Fathullah

Keyword(s):

Degree Of Freedom ◽

End Effector

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Parametric Design of a Spherical Eight-Bar Linkage Based on a Spherical Parallel Manipulator

Journal of Mechanisms and Robotics ◽

10.1115/1.2959093 ◽

2008 ◽

Vol 1 (1) ◽

Cited By ~ 5

Author(s):

Gim Song Soh ◽

J. Michael McCarthy

Keyword(s):

Inverse Kinematics ◽

Parallel Manipulator ◽

Parametric Design ◽

Degree Of Freedom ◽

Kinematics Analysis ◽

End Effector ◽

Arbitrary Base ◽

Three Degree Of Freedom ◽

Spherical Parallel Manipulator

This paper presents a procedure that determines the dimensions of two constraining links to be added to a three degree-of-freedom spherical parallel manipulator so that it becomes a one degree-of-freedom spherical (8, 10) eight-bar linkage that guides its end-effector through five task poses. The dimensions of the spherical parallel manipulator are unconstrained, which provides the freedom to specify arbitrary base attachment points as well as the opportunity to shape the overall movement of the linkage. Inverse kinematics analysis of the spherical parallel manipulator provides a set of relative poses between all of the links, which are used to formulate the synthesis equations for spherical RR chains connecting any two of these links. The analysis of the resulting spherical eight-bar linkage verifies the movement of the system.

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Determination of the Singularity Loci of Spherical Three-Degree-of-Freedom Parallel Manipularors

22nd Biennial Mechanisms Conference: Robotics, Spatial Mechanisms, and Mechanical Systems ◽

10.1115/detc1992-0231 ◽

1992 ◽

Author(s):

Clément M. Gosselin ◽

Jaouad Sefrioui

Keyword(s):

Graphical Representation ◽

Jacobian Matrix ◽

Parallel Manipulators ◽

Degree Of Freedom ◽

End Effector ◽

Cartesian Space ◽

Singularity Locus ◽

Three Degree Of Freedom ◽

Analytical Expressions

Abstract In this paper, an algorithm for the determination of the singularity loci of spherical three-degree-of-freedom parallel manipulators with prismatic atuators is presented. These singularity loci, which are obtained as curves or surfaces in the Cartesian space, are of great interest in the context of kinematic design. Indeed, it has been shown elsewhere that parallel manipulators lead to a special type of singularity which is located inside the Cartesian workspace and for which the end-effector becomes uncontrollable. It is therfore important to be able to identify the configurations associated with theses singularities. The algorithm presented is based on analytical expressions of the determinant of a Jacobian matrix, a quantity that is known to vanish in the singular configurations. A general spherical three-degree-of-freedom parallel manipulator with prismatic actuators is first studied. Then, several particular designs are investigated. For each case, an analytical expression of the singularity locus is derived. A graphical representation in the Cartesian space is then obtained.

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