scholarly journals Impedance-Based Cable Force Monitoring in Tendon-Anchorage Using Portable PZT-Interface Technique

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Thanh-Canh Huynh ◽  
Jeong-Tae Kim
Keyword(s):  
Analytical Model ◽  
Frequency Band ◽  
Theoretical Background ◽  
Test Structure ◽  
Degree Of Freedom ◽  
Damage Evaluation ◽  
Electromechanical Impedance ◽  
Cable Force ◽  
Force Monitoring ◽  
Evaluation Approaches

In this paper, a portable PZT interface for tension force monitoring in the cable-anchorage subsystem is developed. Firstly, the theoretical background of the impedance-based method is presented. A few damage evaluation approaches are outlined to quantify the variation of impedance signatures. Secondly, a portable PZT interface is designed to monitor impedance signatures from the cable-anchorage subsystem. One degree-of-freedom analytical model of the PZT interface is established to explain how to represent the loss of cable force from the change in the electromechanical impedance of the PZT interface as well as reducing the sensitive frequency band by implementing the interface device. Finally, the applicability of the proposed PZT-interface technique is experimentally evaluated for cable force-loss monitoring in a lab-scaled test structure.

Application of optical fiber Bragg grating strain gauge to cable force monitoring of FAST

2015 ◽  
Vol 23 (4) ◽  
pp. 919-925 ◽  
Author(s):  
孙晓 SUN Xiao ◽  
王启明 WANG Qi-ming ◽  
朱明 ZHU Ming ◽  
吴明长 WU Ming-chang
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
Strain Gauge ◽  
Bragg Grating ◽  
Cable Force ◽  
Force Monitoring ◽  
Optical Fiber Bragg Grating

Flexure-Based Two Degree-of-Freedom Legs for Walking Microrobots

2006 ◽  
Author(s):  
Ankur M. Mehta ◽  
Kristofer S. J. Pister
Keyword(s):  
Analytical Model ◽  
Design Space ◽  
Beam Theory ◽  
Degree Of Freedom ◽  
Bernoulli Beam ◽  
Comb Drive ◽  
Walking Gait ◽  
Euler Bernoulli Beam ◽  
Force Displacement ◽  
Two Degree Of Freedom

This work examines the design of legs for a walking microrobot. The parameterized force-displacement relationships of planar serpentine flexure-based two degree-of-freedom legs are analyzed. An analytical model based on Euler-Bernoulli beam theory is developed to explore the design space, and is subsequently refined to include contact between adjacent beams. This is used to determine a successful leg geometry given dimensional constraints and actuator limitations. Standard comb drive actuators that output 100 μN of force over a 15 μm bi-directional throw are shown able to drive a walking gait with three legs on a 1 cm2 silicon die microrobot. If the comb drive suspensions cannot withstand the generated reaction moments, an alternate pivot-based leg linkage is proposed.

scholarly journals Models of stents – Comparison and applications

2007 ◽  
pp. S115-S121
Author(s):  
J Záhora ◽  
A Bezrouk ◽  
J Hanuš
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Analytical Model ◽  
Model Evaluation ◽  
Structural Mechanics ◽  
Theoretical Background ◽  
Measurement Equipment ◽  
The Finite Element Method ◽  
Basic Properties ◽  
New Models

The aim of this study was to analyze the possibilities of various types of stent modeling and to develop some new models. A brief survey of basic properties of stents and a list of basic designs of stents is presented. Two approaches to stent modeling were identified. Structural mechanics is the theoretical background of our analytical model of a spiral stent. The finite element method was also used. The measurement equipment for model evaluation was developed.

scholarly journals Dressing Tool Condition Monitoring through Impedance-Based Sensors: Part 2—Neural Networks and K-Nearest Neighbor Classifier Approach

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4453 ◽  
Author(s):  
Pedro Junior ◽  
Doriana D’Addona ◽  
Paulo Aguiar ◽  
Roberto Teti
Keyword(s):  
Neural Networks ◽  
Frequency Band ◽  
Nearest Neighbor ◽  
K Nearest Neighbor ◽  
Electromechanical Impedance ◽  
Nearest Neighbor Classifier ◽  
Tool Condition ◽  
Dressing Tool ◽  
Sensor Monitoring ◽  
Neighbor Classifier

This paper presents an approach for impedance-based sensor monitoring of dressing tool condition in grinding by using the electromechanical impedance (EMI) technique. This method was introduced in Part 1 of this work and the purpose of this paper (Part 2) is to achieve an optimal selection of the excitation frequency band based on multi-layer neural networks (MLNN) and k-nearest neighbor classifier (k-NN). The proposed approach was validated on the basis of dressing tool condition information obtained from the monitoring of experimental dressing tests with two industrial stationary single-point dressing tools. Moreover, representative damage indices for diverse damage cases, obtained from impedance signatures at different frequency bands, were taken into account for MLNN data processing. The intelligent system was able to select the most damage-sensitive features based on optimal frequency band. The best models showed a general overall error lower than 2%, thus robustly contributing to the efficient automation of grinding and dressing operations. The promising results of this study foster the EMI-based sensor monitoring approach to fault diagnosis in dressing operations and its effective implementation for industrial grinding process automation.

Force-monitoring ring based on white-light interferometry for bridge cable force monitoring and its temperature compensation

2018 ◽  
Vol 22 (6) ◽  
pp. 1444-1452
Author(s):  
Shengyuan Li ◽  
Haifeng Lv ◽  
Yachuan Kuang ◽  
Nianchun Deng ◽  
Changsen Sun ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
White Light ◽  
Temperature Compensation ◽  
Bragg Grating ◽  
White Light Interferometry ◽  
Comparison Results ◽  
Cable Force ◽  
Force Monitoring ◽  
Bridge Cable

This article proposes a novel white-light interference (WLI) force-monitoring ring for bridge cable force monitoring and temperature compensation. The WLI force-monitoring ring employs a sensing optical fiber wrapped around the outer surface of an elastomer to measure the expansion caused by applied load and temperature. By installing WLI force-monitoring ring between the anchor plate and the spherical plate of the cable, cable force can be captured by the sensing optical fiber and thus measured after temperature compensation. Based on white-light interferometry, two force-monitoring rings with resolution of 0.25 µ are designed. To find a route to temperature compensation, laboratory experiments are carried to study the effects of temperature on WLI force-monitoring ring both in free and forced states. Theoretical analysis and calibration experiments are implemented to verify the effectiveness of the proposed WLI force-testing ring, and the experiment results expose that the temperature-induced strain can be compensated using a WLI force-monitoring ring in free state. As a comparison, similar work is made for four fiber Bragg grating sensors attached to the elastomer evenly near the sensing optical fiber. The comparison results verify that the WLI method achieves better linear relation and repeatability than fiber Bragg grating. The WLI force-monitoring ring provides a high-precision and low-cost method for bridge cable force monitoring.

Analytical Model Development and Model Reduction for Electromechanical Brake System

2004 ◽  
Author(s):  
Jaeho Kwak ◽  
Bin Yao ◽  
Anil Bajaj
Keyword(s):  
Analytical Model ◽  
Model Development ◽  
Low Frequency ◽  
Degree Of Freedom ◽  
Design Stage ◽  
Simplified Models ◽  
Contact Mode ◽  
Early Design Stage ◽  
Invaluable Tool ◽  
Electromechanical Brake

This paper presents a detailed analytical model development which can describe the dynamic behavior of the electromechanical brake-by-wire (BBW) system over the entire operating range. The complete model has 10 degree-of-freedom (DOF) and includes essential nonlinearities such as gear backlashes, Coulomb frictions, and disk gap clearance. Such a full model is reduced to 6 degree-of-freedom model in SIMULINK for simulation study of the effectiveness and the achievable performance of different hardware and controller designs, an invaluable tool in the early design stage of a product. Simulation results show that the model is able to reproduce various nonlinear characteristics including typical structural hysteresis as shown in real brake assembly. The linearized version of the full nonlinear model is then obtained for its modal properties to understand the modes that are critical to the low frequency dynamics of the overall system. The results of the modal analyses are subsequently utilized to obtain two simplified models, one for non-contact mode and the other for the contact mode of operation. The concepts of two simplified models well capture the dynamic characteristics of the system over the frequencies of interest and are being used in the controller (e.g., clamping force control) and estimator (e.g., gap clearance estimation) designs that are under investigation.

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