scholarly journals Structural Synthesis of Multi-Fingered Hands

2002 ◽  
Vol 124 (2) ◽  
pp. 272-276 ◽  
Author(s):  
Jyh-Jone Lee ◽  
Lung-Wen Tsai
Keyword(s):  
Degrees Of Freedom ◽  
Structural Characteristics ◽  
Human Hand ◽  
Functional Requirements ◽  
Structural Synthesis ◽  
Constraint Equations ◽  
Mechanical Hand ◽  
Force Closure ◽  
Systematic Enumeration ◽  
Mechanical Hands

The kinematic structure of a mechanical hand typically resembles the skeleton of a human hand and it is usually designed to emulate a subset of the functions of a human hand. This paper analyzes the structural characteristics associated with the functional requirements of a mechanical hand. Using the mobility criterion and force closure concept, constraint equations for structural synthesis of multi-fingered mechanical hands are derived. A procedure for systematic enumeration of the kinematic structures of mechanical hands is established. An atlas of feasible kinematic structures of multi-fingered hands having a mobility number ranging from 3 to 6 and contact degrees of freedom ranging from 1 to 5 is developed. Further, two theorems concerning the structural characteristics of mechanical hands are presented.

scholarly journals On the Structural Synthesis of Multi-Fingered Hands

2000 ◽  
Author(s):  
Jyh-Jone Lee ◽  
Chun-Po Chen
Keyword(s):  
Contact Geometry ◽  
Human Hand ◽  
Robot Arm ◽  
Structural Synthesis ◽  
End Effector ◽  
New Approach ◽  
Mechanical Hand ◽  
Autonomous Manipulation ◽  
Force Closure ◽  
Human Hands

Abstract Compared to the serial type of six-freedom robot arm attached with an end-effector, the multi-fingered hand system can provide more dexterity and versatility in the field of autonomous manipulation tasks. Designs of multi-fingered hands can be found in the literature, to name a few, Mechanical Hand by Skinner [13], Multi-jointed Finger System by Okada [6], Stanford/JPL Hand (or Salisbury Hand) [11], Utah-MIT Hand [3], and NTU-1 Hand [5]. Generally, these mechanical hand systems have been designed to simulate a subset function of human hands. The structures of these systems basically resemble the skeleton of human hand and are constructed by designers’ intuition. Not much literature addressed about the structural synthesis of multi-fingered hands. This paper presents a new approach for the structural synthesis of multi-fingered hands. It takes into account both the total mobility and the force closure criterion of the system. Based upon the Grübler’s mobility equation, relations regarding the numbers of fingers, contact geometry, and object freedoms are established. Subsequently, by applying the force closure criterion, the total number of possible multi-fingered hands with given mobility are synthesized.

Structural Synthesis of Baranov Trusses With Up to 13 Links

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Peng Huang ◽  
Huafeng Ding
Keyword(s):  
Open Problem ◽  
Structural Characteristics ◽  
Detection Algorithm ◽  
Synthesis Methods ◽  
Structural Synthesis ◽  
Topological Graphs ◽  
Systematic Method ◽  
Constraint Equations ◽  
Complete Set ◽  
Graph Form

The structural synthesis of Baranov trusses is still an open problem, although Baranov trusses are widely used in the design and analysis of mechanisms and robots. This paper proposes a systematic method for the structural synthesis of Baranov trusses. First, the definition review and the graph-form representations of Baranov trusses are proposed. Second, seven propositions on structural characteristics of Baranov trusses are concluded. Then, based on the set of constraint equations and a rigid subchain detection algorithm, a systematic method is presented to synthesize the complete set of Baranov trusses with a specified number of links. Finally, the synthesis results of contracted graphs (including valid and rigid contracted graphs) and topological graphs of Baranov trusses with up to 13 links are provided, and the synthesis methods and results between ours and the ones in the existing literature are compared and discussed in detail.

Kinematic Analysis and Synthesis of the Knotting Mechanisms Can be Used in the Production of Handmade Carpet: A Case Study

2005 ◽  
Vol 219 (9) ◽  
pp. 987-1005 ◽  
Author(s):  
M Topalbekiroğlu
Keyword(s):  
Structural Characteristics ◽  
Complex Structure ◽  
Synthesis Method ◽  
Production Method ◽  
Human Hand ◽  
Functional Requirements ◽  
Dimensional Synthesis ◽  
New Production ◽  
Analysis And Synthesis

The weaving process in a handmade carpet contains independent knots, which have a complex structure. A new production method, mechanism, or machine for producing knots in handmade carpets has not been developed since thousands of years. They are still woven by human hand. Two different types of knots are used to form handmade carpets, which are called as the Turkish (Gördes knot) and the Persian (Sehna knot) knots. In this article, the conceptual design and dimensional synthesis for mechanisms used to produce these knots are studied. To generate all-acceptable one-degree of freedom (DOF) and two-DOF planar knotting mechanism, a systematic methodology is presented. First, the functional requirements of the knotting mechanism are established according to the problem statement. Some of the functional requirements of the knotting mechanism are then translated into the structural characteristics of mechanism. On the basis of the requirements and the structural considerations, the unwanted mechanism is screened out. Finally, two different mechanisms are developed for the knotting mechanism and their dimensions are determined by dimensional synthesis method.

The Structural Synthesis of Tendon-Driven Manipulators Having a Pseudotriangular Structure Matrix

1991 ◽  
Vol 10 (3) ◽  
pp. 255-262 ◽  
Author(s):  
Jyh-Jone Lee ◽  
Lung-Wen Tsai
Keyword(s):  
Degrees Of Freedom ◽  
Power Transmission ◽  
Structural Characteristics ◽  
Mechanical Systems ◽  
Structural Synthesis ◽  
Structure Matrix ◽  
Six Degrees Of Freedom ◽  
Structural Isomorphism

Tendons have been widely used for power transmission in the field of anthropomorphic manipulating systems. This article deals with the identification and enumeration of the kine matic structure of tendon-driven robotic mechanisms. The structural isomorphism of tendon-driven manipulators is defined, and the structural characteristics of such mechanical systems are described. Applying these structural characteris tics, a methodology for the enumeration of tendon-driven robotic mechanisms is developed. Mechanism structures with up to six degrees of freedom are enumerated.

Design and Analysis of Parallel Mechanism with Linear Drives Located on the Base at Specified Angles

2021 ◽  
pp. 41-48
Author(s):  
Y.V. Rodionov ◽  
A.N. Sukhostavskiy ◽  
A.A. Romanov ◽  
A.V. Dukhov ◽  
I.V. Pelin
Keyword(s):  
Coordinate System ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Chain ◽  
Relative Movement ◽  
Structural Synthesis ◽  
Output Link ◽  
Constraint Equations ◽  
Inverse Kinematics Problem

The article considers a novel parallel mechanism with drives located on the base at different angles to its plane. This arrangement allows performing a relative movement between objects under water or in space (in aggressive environments). The new mechanism topology is compact for transportation and efficient for operation in aggressive environments. Structural synthesis has been performed; the number of degrees of freedom of the output link was calculated. A general approach to solving the inverse kinematics problem of positions is proposed and an example for a kinematic chain is shown. Denavit — Hartenberg matrices are used to solve the problem of positions. The position of the output link described by this matrix is used to represent the points of this link in the base coordinate system. The constraint equations are applied, which are the distances between the points of the base and the output link.

scholarly journals Beyond Soft Hands: Efficient Grasping With Non-Anthropomorphic Soft Grippers

2021 ◽  
Vol 8 ◽  
Author(s):  
Yufei Hao ◽  
Yon Visell
Keyword(s):  
Degrees Of Freedom ◽  
Robotic Systems ◽  
Human Hand ◽  
Detailed Knowledge ◽  
New Techniques ◽  
Research Directions ◽  
Challenging Tasks ◽  
Force Closure ◽  
Grasping And Manipulation ◽  
And Control

Grasping and manipulation are challenging tasks that are nonetheless critical for many robotic systems and applications. A century ago, robots were conceived as humanoid automata. While conceptual at the time, this viewpoint remains influential today. Many robotic grippers have been inspired by the dexterity and functionality of the prehensile human hand. However, multi-fingered grippers that emulate the hand often integrate many kinematic degrees-of-freedom, and thus complex mechanisms, which must be controlled in order to grasp and manipulate objects. Soft fingers can facilitate grasping through intrinsic compliance, enabling them to conform to diverse objects. However, as with conventional fingered grippers, grasping via soft fingers involves challenges in perception, computation, and control, because fingers must be placed so as to achieve force closure, which depends on the shape and pose of the object. Emerging soft robotics research on non-anthropomorphic grippers has yielded new techniques that can circumvent fundamental challenges associated with grasping via fingered grippers. Common to many non-anthropomorphic soft grippers are mechanisms for morphological deformation or adhesion that simplify the grasping of diverse objects in different poses, without detailed knowledge of the object geometry. These advantages may allow robots to be used in challenging applications, such as logistics or rapid manufacturing, with lower cost and complexity. In this perspective, we examine challenges associated with grasping via anthropomorphic grippers. We describe emerging soft, non-anthropomorphic grasping methods, and how they may reduce grasping complexities. We conclude by proposing several research directions that could expand the capabilities of robotic systems utilizing non-anthropomorphic grippers.

scholarly journals Soft Exoskeletons: Development, Requirements, and Challenges of the Last Decade

Actuators ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 166
Author(s):  
Alan Francisco Pérez Vidal ◽  
Jesse Yoe Rumbo Morales ◽  
Gerardo Ortiz Torres ◽  
Felipe de Jesús Sorcia Vázquez ◽  
Alan Cruz Rojas ◽  
...  
Keyword(s):  
Control Systems ◽  
Degrees Of Freedom ◽  
Power Transmission ◽  
Structural Characteristics ◽  
Current Trend

In this article, various investigations on soft exoskeletons are presented and their functional and structural characteristics are analyzed. The present work is oriented to the studies of the last decade and covers the upper and lower joints, specifically the shoulder, elbow, wrist, hand, hip, knee, and ankle. Its functionality, applicability, and main characteristics are exposed, such as degrees of freedom, force, actuators, power transmission methods, control systems, and sensors. The purpose of this work is to show the current trend in the development of soft exoskeletons, in addition to specifying the essential characteristics that must be considered in its design and the challenges that its construction implies.

scholarly journals Human Hand Anatomy-Based Prosthetic Hand

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 137
Author(s):  
Larisa Dunai ◽  
Martin Novak ◽  
Carmen García Espert
Keyword(s):  
3D Printing ◽  
Degrees Of Freedom ◽  
Use Of Force ◽  
Hand Movements ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Object Surface ◽  
Hand Phalanges ◽  
High Level

The present paper describes the development of a prosthetic hand based on human hand anatomy. The hand phalanges are printed with 3D printing with Polylactic Acid material. One of the main contributions is the investigation on the prosthetic hand joins; the proposed design enables one to create personalized joins that provide the prosthetic hand a high level of movement by increasing the degrees of freedom of the fingers. Moreover, the driven wire tendons show a progressive grasping movement, being the friction of the tendons with the phalanges very low. Another important point is the use of force sensitive resistors (FSR) for simulating the hand touch pressure. These are used for the grasping stop simulating touch pressure of the fingers. Surface Electromyogram (EMG) sensors allow the user to control the prosthetic hand-grasping start. Their use may provide the prosthetic hand the possibility of the classification of the hand movements. The practical results included in the paper prove the importance of the soft joins for the object manipulation and to get adapted to the object surface. Finally, the force sensitive sensors allow the prosthesis to actuate more naturally by adding conditions and classifications to the Electromyogram sensor.

Miniaturized Pneumatic Artificial Muscles Actuating a Bio-Inspired Robot Hand

2013 ◽  
Author(s):  
Thomas E. Pillsbury ◽  
Ryan M. Robinson ◽  
Norman M. Wereley
Keyword(s):  
Degrees Of Freedom ◽  
Full Scale ◽  
Constitutive Relationship ◽  
Force Density ◽  
Human Hand ◽  
Artificial Muscles ◽  
Specific Work ◽  
Robotic Hand ◽  
Robot Hand ◽  
Pneumatic Artificial Muscles

Pneumatic artificial muscles (PAMs) are used in robotics applications for their light-weight design and superior static performance. Additional PAM benefits are high specific work, high force density, simple design, and long fatigue life. Previous use of PAMs in robotics research has focused on using “large,” full-scale PAMs as actuators. Large PAMs work well for applications with large working volumes that require high force and torque outputs, such as robotic arms. However, in the case of a compact robotic hand, a large number of degrees of freedom are required. A human hand has 35 muscles, so for similar functionality, a robot hand needs a similar number of actuators that must fit in a small volume. Therefore, using full scale PAMs to actuate a robot hand requires a large volume which for robotics and prosthetics applications is not feasible, and smaller actuators, such as miniature PAMs, must be used. In order to develop a miniature PAM capable of producing the forces and contractions needed in a robotic hand, different braid and bladder material combinations were characterized to determine the load stroke profiles. Through this characterization, miniature PAMs were shown to have comparably high force density with the benefit of reduced actuator volume when compared to full scale PAMs. Testing also showed that braid-bladder interactions have an important effect at this scale, which cannot be modeled sufficiently using existing methods without resorting to a higher-order constitutive relationship. Due to the model inaccuracies and the limited selection of commercially available materials at this scale, custom molded bladders were created. PAMs created with these thin, soft bladders exhibited greatly improved performance.

Architecture Optmization of a 3-DOF Parallel Mechanism

1998 ◽  
Author(s):  
J. A. Carretero ◽  
R. P. Podhorodeski ◽  
M. Nahon
Keyword(s):  
Parallel Mechanism ◽  
Architectural Design ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Design Parameters ◽  
Objective Functions ◽  
Constraint Equations ◽  
Three Degree Of Freedom ◽  
Architecture Optimization ◽  
Three Degrees Of Freedom

Abstract This paper presents a study of the architecture optimization of a three-degree-of-freedom parallel mechanism intended for use as a telescope mirror focussing device. The construction of the mechanism is first described. Since the mechanism has only three degrees of freedom, constraint equations describing the inter-relationship between the six Cartesian coordinates are given. These constraints allow us to define the parasitic motions and, if incorporated into the kinematics model, a constrained Jacobian matrix can be obtained. This Jacobian matrix is then used to define a dexterity measure. The parasitic motions and dexterity are then used as objective functions for the optimizations routines and from which the optimal architectural design parameters are obtained.

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