scholarly journals Dimensional Synthesis of Wristed Binary Hands

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Neda Hassanzadeh ◽  
Alba Perez-Gracia
Keyword(s):  
Robot Manipulator ◽  
Dimensional Synthesis ◽  
Design Strategies ◽  
Robotic Hands ◽  
Kinematic Synthesis ◽  
Multifingered Hands ◽  
Position Task ◽  
Grasping And Manipulation ◽  
Manipulator Arm ◽  
Tree Topologies

The kinematic synthesis applied to tree topologies is a tool for the design of multifingered robotic hands, for a simultaneous task of all fingertips. Even though traditionally wrists and hands have been designed separately, the wrist usually being part of the robot manipulator arm, it makes sense to consider the wrist as a part of the hand, as many grasping and manipulation actions are a coordinated action of wrist and fingers. The manipulation capabilities of robotic hands may also be enhanced by considering more than one splitting stage, as opposed to the single-palm traditional hand. In this work, we present the dimensional synthesis for a family of multifingered hands, the binary hands, which have a 2R wrist and several splitting stages, each of them spanning two branches consisting of a revolute joint for each edge. For these topologies, it is proved that a three-position task can be defined for each fingertip, regardless of the number of fingers. One example is presented to show the possible design strategies and uses for this family of hands.

A Design Implementation Process for Robotic Hand Synthesis

2015 ◽  
Author(s):  
Neda Hassanzadeh ◽  
Xiangwei He ◽  
Alba Perez-Gracia
Keyword(s):  
Computer Aided Design ◽  
Implementation Process ◽  
Robotic Hand ◽  
Dimensional Synthesis ◽  
Robotic Hands ◽  
Detailed Design ◽  
Kinematic Synthesis ◽  
Friction Forces ◽  
Starting Point ◽  
Higher Derivatives

The design of multi-fingered robotic hands can follow a kinematic synthesis approach, in which a trajectory or set of points and higher derivatives are defined for each fingertip. The output of the dimensional synthesis is a set of joint axes, effectively defining the basic kinematic structure of the hand. In the case of spatial motion, there seems to be a big gap between the results of the dimensional synthesis and a real and effective detailed design of the robotic hand, this being one of the reasons why synthesis is not regularly used in the design of robotic hands. This work aims to reduce the gap from kinematic synthesis to detailed, computer-aided design of robotic hands. In order to do so, the output of the dimensional synthesis is first used as the input of a link-based optimization process, aim to bring to reasonable values requirements such as link lengths, internal friction forces and obstacle avoidance, including self-intersection. The optimized results are automatically imported to a popular solid modeling software, creating reference geometry for parts, and joint axes and anchor points for the final hand assembly. At the same time, a database of hand parts is presented to the user to select and adapt in order to create a first realistic assembly of the robotic hand. The output of the process is a first detailed design of the robotic hand, which can be a good starting point for the designer to implement transmission and actuation in further stages.

Geometric Design of Symmetric 3-RRS Constrained Parallel Platforms

2004 ◽  
Author(s):  
Eric Wolbrecht ◽  
Hai-Jun Su ◽  
Alba Perez ◽  
J. Michael McCarthy
Keyword(s):  
Geometric Design ◽  
Homotopy Continuation ◽  
Total Degree ◽  
Polynomial Equations ◽  
Dimensional Synthesis ◽  
Kinematic Synthesis ◽  
Real Solutions ◽  
Parallel Platform ◽  
Three Degree Of Freedom ◽  
Serial Chains

The paper presents the kinematic synthesis of a symmetric parallel platform supported by three RRS serial chains. The dimensional synthesis of this three degree-of-freedom system is obtained using design equations for each of three RRS chains obtained by requiring that they reach a specified set of task positions. The result is 10 polynomial equations in 10 unknowns, which is solved using polynomial homotopy continuation. An example is provided in which the direction of the first revolute joint (2 parameters) and the z component of the base and platform are specified as well as the two task positions. The system of polynomials has a total degree of 4096 which means that in theory it can have as many solutions. Our example has 70 real solutions that define 70 different symmetric platforms that can reach the specified positions.

Robotic location of underground chemical sources

Robotica ◽  
2004 ◽  
Vol 22 (1) ◽  
pp. 109-115 ◽  
Author(s):  
R. Andrew Russell
Keyword(s):  
Robot Manipulator ◽  
Search Algorithm ◽  
Chemical Vapour ◽  
Coarse Sand ◽  
Land Mines ◽  
Factors Affecting ◽  
Sensory Environment ◽  
Manipulator Arm ◽  
Unexploded Ordinance ◽  
Sensor Probe

This paper describes current progress in a project to develop robotic systems for locating underground chemical sources. There are a number of economic and humanitarian applications for this technology. Finding unexploded ordinance, land mines, and sources of leaks from pipes and tanks are some examples. Initial experiments were conducted using an ethanol chemical source buried in coarse sand. To gain an understanding of the sensory environment that would be experienced by a robot burrowing through the ground, the factors affecting transport of chemical vapour through soil were investigated. A robot search algorithrn was then developed for gathering chemical gradient inforrnation and using this to guide a robot towards the source. Experiments were performed using a chemical sensing probe positioned by a UMI RTX robot manipulator arm. The resulting system was successful in locating a source of ethanol vapour buried in sand. This paper includes details of experiments to characterise the sand used in this project, the robot search algorithm, sensor probe and results of source location trials.

Kinematic Synthesis of Spatial R-R Dyads for Path Following Revisited Using the Rotation Matrix Approach

1999 ◽  
Author(s):  
Venkat Krovi ◽  
G. K. Ananthasuresh ◽  
Vijay Kumar
Keyword(s):  
Linear System ◽  
Path Following ◽  
Rotation Matrix ◽  
Dimensional Synthesis ◽  
Kinematic Synthesis ◽  
End Effector ◽  
Serial Chain ◽  
Systematic Development ◽  
Matrix Vector ◽  
Selection Of

Abstract We revisit the dimensional synthesis of a spatial two-link, two revolute-jointed serial chain for path following applications, focussing on the systematic development of the design equations and their analytic solution for the three precision point synthesis problem. The kinematic design equations are obtained from the equations of loop-closure for end-effector position in rotation-matrix/vector form at the three precision points. These design equations form a rank-deficient linear system in the link-vector components. The nullspace of the rank deficient linear system is then deduced analytically and interpreted geometrically. Tools from linear algebra are applied to systematically create the auxiliary conditions required for synthesis and to verify consistency. An analytic procedure for obtaining the link-vector components is then developed after a suitable selection of free choices. Optimization over the free choices is possible to permit the matching of additional criteria and explored further. Examples of the design of optimal two-link coupled spatial R-R dyads are presented where the end-effector interpolates three positions exactly and closely approximates an entire desired path.

Conditions of Parametric Resonance in Periodically Time-Variant Systems With Distributed Parameters

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Yong-Kwan Lee ◽  
Leonid S. Chechurin
Keyword(s):  
Parametric Resonance ◽  
Robot Manipulator ◽  
Synchronous Generator ◽  
Constant Current ◽  
Time Varying ◽  
Distributed Parameters ◽  
Time Varying Parameter ◽  
Manipulator Arm ◽  
The Stability ◽  
Systems With Distributed Parameters

Theoretical analysis of the stability problem for the control systems with distributed parameters shall be given. The approach to the analysis of such systems can be composed of two parts. First, the distributed parameter element is modeled by a frequency response function. Second, approximate conditions of parametric resonance are derived by a method of stationarization (describing functions of time-variant elements). The approach is illustrated by two examples. One is a robot-manipulator arm (distributed mechanical parameter system) controlled by a controller with a modulator/demodulator cascade (time-varying element). Another is an electromechanical transformer that consists of a constant current motor and a synchronous generator. Inductance between stator windings and the rotor of the synchronous generator serves as a periodical time-varying parameter, and a long electrical line plays the role of an element with distributed parameters. In both examples, dangerous (in terms of the first parametric resonance) regions for time-varying parameter are obtained theoretically and compared with simulation experiment.

scholarly journals Kinematic Analysis and Dimensional Synthesis of a Meso-Gripper

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
Guochao Bai ◽  
Xianwen Kong ◽  
James Millar Ritchie
Keyword(s):  
Size Range ◽  
Dimensional Synthesis ◽  
Mesoscopic Scale ◽  
Robotic Hands ◽  
Modes Of Operation ◽  
Digital Multimedia ◽  
Dual Functional ◽  
Industrial Assembly ◽  
3D Printed ◽  
Constraint Method

Abstract In recent years, applications in industrial assemblies within a size range from 0.5 mm to 100 mm are increasing due to the large demands for new products, especially those associated with digital multimedia. Research on grippers or robotic hands within the mesoscopic scale of this range has not been explored in any great detail. This paper outlines the development of a gripper to bridge the gap between microgrippers and macrogrippers by extending the gripping range to the mesoscopic scale, particularly without the need to switch grippers during industrial assembly. The mesoscopic scale gripper (meso-gripper) researched in this work has two modes of operation: passive adjusting mode and angled gripping mode, adapting its configuration to the shape of object automatically. This form of gripping and the associated mechanism are both novel in their implementation and operation. First, the concept of mesoscopic scale in robotic gripping is presented and contextualized around the background of inefficient hand switching processes and applications for assembly. The passive adjusting and angled gripping modes are then analyzed and a dual functional mechanism design proposed. A geometric constraint method is then demonstrated which facilitates task-based dimensional synthesis after which the kinematics of synthesized mechanism is investigated. The modified synthesized mechanism gripper is then investigated according to stiffness and layout. Finally, a 3D printed prototype is successfully tested, and the two integrated gripping modes for universal gripping verified.

Kinematic Synthesis of a Spatial 3-RPS Parallel Manipulator

2003 ◽  
Vol 125 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Han Sung Kim ◽  
Lung-Wen Tsai
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Parallel Manipulators ◽  
Point Of View ◽  
Dimensional Synthesis ◽  
Kinematic Synthesis ◽  
End Effector ◽  
Solution Methods ◽  
Moving Platform ◽  
At Will

This paper presents the design of spatial 3-RPS parallel manipulators from dimensional synthesis point of view. Since a spatial 3-RPS manipulator has only 3 degrees of freedom, its end effector cannot be positioned arbitrarily in space. It is shown that at most six positions and orientations of the moving platform can be prescribed at will and, given six prescribed positions, there are at most ten RPS chains that can be used to construct up to 120 manipulators. Further, solution methods for fewer than six prescribed positions are also described.

A Frequency Domain Identification Scheme for Control and Fault Diagnosis

1997 ◽  
Vol 119 (1) ◽  
pp. 48-56 ◽  
Author(s):  
G. Mallory ◽  
R. Doraiswami
Keyword(s):  
Frequency Domain ◽  
Linear Time ◽  
Robot Manipulator ◽  
Physical Parameters ◽  
Linear Time Invariant ◽  
Domain Identification ◽  
Frequency Domain Identification ◽  
Identification Technique ◽  
Manipulator Arm ◽  
Linear Time Invariant System

A robust scheme to estimate a set of models for a linear time-invariant system, subject to perturbations in the physical parameters, from a frequency response data record is proposed. The true model as well as the disturbances affecting the system are assumed unknown. However, the physical parameters are assumed to enter the coefficients of the system transfer function multilinearly. A set of models is identified by perturbing the physical parameters one-at-time and using a frequency domain identification technique. Exploiting the assumed multilinearity, the estimated set of models is validated. The proposed scheme is evaluated on a number of simulated systems, and on a physical robot manipulator arm.

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