Synthesizing Parallel Flexure Concepts That Mimic the Complex Kinematics of Serial Flexures Using Displaced Screw Systems

2011 ◽  
Author(s):  
Jonathan B. Hopkins
Keyword(s):  
Case Studies ◽  
Degrees Of Freedom ◽  
General Purpose ◽  
Geometric Shapes ◽  
New Type ◽  
Motion Stage ◽  
Precision Motion

The aim of this paper is to introduce the theory necessary to synthesize a new type of parallel flexure system that mimics the complex kinematics of serial flexure systems using a comprehensive library of geometric shapes that represent systems of screws. By displacing these shapes far from the system’s motion stage, designers may rapidly visualize every parallel flexure concept that possesses degrees of freedom (DOFs), which approximate DOFs only achievable by serial flexure systems for small motions. In this way, designers may generate every flexure concept that utilizes the advantages of both parallel and serial flexure systems. This paper’s impact is most significant to the design of precision motion stages, optical mounts, microscopy stages, and general purpose flexure bearings. Two case studies are provided to demonstrate the utility of this theory.

Synthesizing Parallel Flexures That Mimic the Kinematics of Serial Flexures Using Freedom and Constraint Topologies

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Jonathan B. Hopkins
Keyword(s):  
Case Studies ◽  
Degrees Of Freedom ◽  
General Purpose ◽  
Complete List ◽  
Geometric Shapes ◽  
Point Of Interest ◽  
Precision Motion ◽  
Constraint Topologies ◽  
Synthesis Approach

The principles of the freedom and constraint topologies (FACT) synthesis approach are adapted and applied to the design of parallel flexure systems that mimic degrees of freedom (DOFs) primarily achievable by serial flexure systems. FACT provides designers with a comprehensive library of geometric shapes. These shapes enable designers to visualize the regions wherein compliant flexure elements may be placed for achieving desired DOFs. By displacing these shapes far from the point of interest of the stage of a flexure system, designers can compare a multiplicity of concepts that utilizes the advantages of both parallel and serial systems. A complete list of which FACT shapes mimic which DOFs when displaced far from the point of interest of the flexure system's stage is provided as well as an intuitive approach for verifying the completeness of this list. The proposed work intends to cater to the design of precision motion stages, optical mounts, microscopy stages, and general purpose flexure bearings. Two case studies are provided to demonstrate the application of the developed procedure.

Synthesizing Soft Parallel Robots Comprised of Active Constraints

2014 ◽  
Author(s):  
Jordan Rivera ◽  
Jonathan B. Hopkins ◽  
Charles Kim
Keyword(s):  
Case Studies ◽  
Degrees Of Freedom ◽  
Parallel Systems ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Soft Robot ◽  
Active Constraints ◽  
New Type ◽  
Constraint Topologies ◽  
Synthesis Approach

In this paper, we introduce a new type of spatial parallel robot that is comprised of soft inflatable constraints called Tri-Chamber Actuators (TCAs). We extend the principles of the Freedom and Constraint Topologies (FACT) synthesis approach to enable the synthesis and analysis of this new type of soft robot. The concepts of passive and active freedom spaces are introduced and applied to the design of general parallel systems that consist of active constraints (i.e., constraint that can be actuated to impart various loads onto the system’s stage) that both drive desired motions and guide the system’s desired degrees of freedom (DOFs). We provide the fabrication details of the TCA constraints introduced in this paper and experimentally validate their FACT-predicted kinematics. Examples are provided as case studies.

Analyzing and Designing Serial Flexure Elements

2013 ◽  
Author(s):  
Jonathan B. Hopkins
Keyword(s):  
Case Studies ◽  
Degrees Of Freedom ◽  
Compliant Mechanisms ◽  
Rigid Bodies ◽  
The Other ◽  
Geometric Shapes ◽  
Other Hand ◽  
Constraint Topologies ◽  
Synthesis Approach

In this paper we introduce the principles necessary to analyze and design serial flexure elements, which may be used to synthesize advanced compliant mechanisms (CMs). The most commonly used flexure elements (e.g., wire, blade, or living hinge flexures) are often parallel and thus impose constraining forces directly through all parts of their geometry to the rigid bodies that they join within the CM. Serial flexure elements, on the other hand, constrain rigid bodies with a larger variety of forces and moments and thus enable CMs to achieve (i) more degrees of freedom (DOFs), (ii) larger dynamic and elastomechanic versatility, and (iii) greater ranges of motion than parallel elements. In this paper, we extend the principles of the Freedom and Constraint Topologies (FACT) synthesis approach such that it enables the synthesis of CMs that are not only constrained by parallel flexure elements, but also by serial elements. FACT utilizes geometric shapes to intuitively guide designers in visualizing compliant element geometries that achieve any desired set of DOFs. In this way, designers can rapidly generate a host of new serial flexure elements for various CM applications. Such elements are provided here as case studies.

scholarly journals Designing hybrid flexure systems and elements using Freedom and Constraint Topologies

2013 ◽  
Vol 4 (2) ◽  
pp. 319-331 ◽  
Author(s):  
J. B. Hopkins
Keyword(s):  
Hybrid Systems ◽  
Case Studies ◽  
Degrees Of Freedom ◽  
Rigid Bodies ◽  
Geometric Shapes ◽  
Design Requirements ◽  
Constraint Topologies ◽  
Exact Constraint ◽  
Synthesis Approach

Abstract. In this paper we introduce the principles necessary to synthesize hybrid flexure systems and elements. Flexure systems consist of rigid bodies that are joined together by flexure elements that elastically deform to guide the system's rigid bodies with desired degrees of freedom (DOFs). The principles introduced here for synthesizing hybrid flexure systems and elements are extensions of the Freedom and Constraint Topologies (FACT) synthesis approach. FACT utilizes a comprehensive library of geometric shapes from which designers can rapidly consider and compare a multiplicity of flexure concepts that achieve any desired set of DOFs. Prior to this paper, designers primarily used these shapes to synthesize parallel and serial flexure systems and elements. With this paper, designers may now use these same shapes to synthesize more general flexures that consist of various combinations of parallel and serial systems and elements (i.e., hybrid configurations). As such, designers can access a larger body of flexure solutions that satisfy demanding design requirements. Instructions for helping designers utilize or avoid the advantages and challenges of over-, under-, and exact-constraint are also provided. Hybrid systems and elements are analysed and designed as case studies.

Identification of a precision motion stage based on the Hammerstein-Wiener model

2019 ◽  
Author(s):  
Zhu Zhang ◽  
Delong Zhang ◽  
Haiyang Zheng ◽  
Tao Huang ◽  
Yangqiu Xie
Keyword(s):  
Wiener Model ◽  
Motion Stage ◽  
Precision Motion

scholarly journals Using Wearable Sensors and a Convolutional Neural Network for Catch Detection in American Football

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6722
Author(s):  
Bernhard Hollaus ◽  
Sebastian Stabinger ◽  
Andreas Mehrle ◽  
Christian Raschner
Keyword(s):  
Neural Network ◽  
Degrees Of Freedom ◽  
Wearable Sensors ◽  
Professional Sports ◽  
American Football ◽  
Data Logging ◽  
Sensor Platform ◽  
Magnetometer Data ◽  
Audio Data ◽  
New Type

Highly efficient training is a must in professional sports. Presently, this means doing exercises in high number and quality with some sort of data logging. In American football many things are logged, but there is no wearable sensor that logs a catch or a drop. Therefore, the goal of this paper was to develop and verify a sensor that is able to do exactly that. In a first step a sensor platform was used to gather nine degrees of freedom motion and audio data of both hands in 759 attempts to catch a pass. After preprocessing, the gathered data was used to train a neural network to classify all attempts, resulting in a classification accuracy of 93%. Additionally, the significance of each sensor signal was analysed. It turned out that the network relies most on acceleration and magnetometer data, neglecting most of the audio and gyroscope data. Besides the results, the paper introduces a new type of dataset and the possibility of autonomous training in American football to the research community.

Selection of Degrees of Freedom for Dynamic Analysis

1987 ◽  
Vol 109 (1) ◽  
pp. 65-69 ◽  
Author(s):  
K. W. Matta
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
General Purpose ◽  
Component Mode Synthesis ◽  
Complex Structures ◽  
Large Complex ◽  
Static Condensation ◽  
Basis Vectors ◽  
Selection Of

A technique for the selection of dynamic degrees of freedom (DDOF) of large, complex structures for dynamic analysis is described and the formulation of Ritz basis vectors for static condensation and component mode synthesis is presented. Generally, the selection of DDOF is left to the judgment of engineers. For large, complex structures, however, a danger of poor or improper selection of DDOF exists. An improper selection may result in singularity of the eigenvalue problem, or in missing some of the lower frequencies. This technique can be used to select the DDOF to reduce the size of large eigenproblems and to select the DDOF to eliminate the singularities of the assembled eigenproblem of component mode synthesis. The execution of this technique is discussed in this paper. Examples are given for using this technique in conjunction with a general purpose finite element computer program GENSAM[1].

scholarly journals Dark Photon Searches at BESIII

2018 ◽  
Vol 46 ◽  
pp. 1860046 ◽  
Author(s):  
Dayong Wang
Keyword(s):  
Degrees Of Freedom ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Gauge Bosons ◽  
Data Set ◽  
Decay Modes ◽  
Dark Photon ◽  
The Standard Model ◽  
New Type ◽  
Low Mass

Many models beyond the Standard Model, motivated by the recent astrophysical anomalies, predict a new type of weak-interacting degrees of freedom. Typical models include the possibility of the low-mass dark gauge bosons of a few GeV and thus making them accessible at the BESIII experiment running at the tau-charm region. The BESIII has recently searched such dark bosons in several decay modes using the high statistics data set collected at charmonium resonaces. This talk will summarize the recent BESIII results of these dark photon searches and related new physics studies.

Design of a Novel Parallel Mechanism for Haptic Device

2021 ◽  
pp. 1-63
Author(s):  
Jin Lixing ◽  
Duan Xingguang ◽  
Li Changsheng ◽  
Shi Qingxin ◽  
Wen Hao ◽  
...  
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Force Feedback ◽  
Parallel Architecture ◽  
General Purpose ◽  
Haptic Device ◽  
Haptic Devices ◽  
Modeling And Optimization ◽  
Teleoperation Systems

Abstract This paper presents a novel parallel architecture with seven active degrees of freedom (DOFs) for general-purpose haptic devices. The prime features of the proposed mechanism are partial decoupling, large dexterous working area, and fixed actuators. The detailed processes of design, modeling, and optimization are introduced and the performance is simulated. After that, a mechanical prototype is fabricated and tested. Results of the simulations and experiments reveal that the proposed mechanism possesses excellent performances on motion flexibility and force feedback. This paper aims to provide a remarkable solution of the general-purpose haptic device for teleoperation systems with uncertain mission in complex applications.

New Type of Hydraulic Rotary Actuator; Development and Application in a Large Telerobotic Manipulator System

2001 ◽  
Author(s):  
John R. Haas
Keyword(s):  
Modular Design ◽  
Large Diameter ◽  
Stick Slip ◽  
Precision Motion Control ◽  
Constant Torque ◽  
Rotary Actuator ◽  
Continuous Rotation ◽  
Potential Applications ◽  
New Type ◽  
Precision Motion

Abstract This paper describes a new type of hydraulic rotary actuator specifically developed to provide precision motion control in a very large, man rated, underwater telerobotic manipulator system. The high pressure, high torque rotary actuators are hydrostatically balanced, provide continuous rotation, constant torque output, exhibit minimal “stick-slip” and zero backlash. It is believed that the combination of features and the performance exhibited by these actuators represent an improvement in actuator technology to such an extent as to make projects previously determined unfeasible, now practical. Features of particular design value are a very large diameter through bore, and a truly modular design permitting use as an integral structural member. This paper will address design rationale, operating principles, key design features, product development highlights, an astronaut trainer case study, future development and potential applications.

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