Feedback Controlled Optomechanical Force Sensor

2011 ◽  
Author(s):  
Jon R. Pratt ◽  
Paul Wilkinson ◽  
Gordon Shaw
Keyword(s):  
Dynamic Properties ◽  
Force Sensor ◽  
Low Noise ◽  
Atomic Scale ◽  
Photon Momentum ◽  
Cantilever Deflection ◽  
Power Intensity ◽  
Intensity Modulated ◽  
And Control ◽  
Excited Oscillator

We present a new servo controllable force sensor that exploits photon momentum forces for the identification, calibration, and control of its dynamic properties. The sensor comprises a millimeter-scale glass cantilever, a low-noise fiber interferometer for detection of the cantilever deflection, and a high-power, intensity-modulated fiber laser to apply optical actuation forces. Combined with appropriate digital and analog signal processing, the sensor has been operated as a feedback-cooled low-noise force sensor, and as a self-excited oscillator governed by the familiar Rayleigh equation. Operated in this self-excited Quber mode, it appears well suited for noncontact, frequency modulated force gradient detection such as in atom discrimination. Here, we briefly lay out the principles of the sensor and provide examples of its performance, including the demonstration of feedback cooling and the ability to induce controlled limit cycle oscillations with atomic scale amplitudes.

scholarly journals Simulation Verification of the Contact Parameter Influence on the Forces’ Course of Cereal Grain Impact against a Stiff Surface

2021 ◽  
Vol 11 (2) ◽  
pp. 466
Author(s):  
Włodzimierz Kęska ◽  
Jacek Marcinkiewicz ◽  
Łukasz Gierz ◽  
Żaneta Staszak ◽  
Jarosław Selech ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Decisive Role ◽  
Force Sensor ◽  
Contact Forces ◽  
Correct Selection ◽  
Contact Parameter ◽  
Cereal Grain ◽  
Wide Range ◽  
The Impact ◽  
Selection Of

The continuous development of computer technology has made it applicable in many scientific fields, including research into a wide range of processes in agricultural machines. It allows the simulation of very complex physical phenomena, including grain motion. A recently discovered discrete element method (DEM) is used for this purpose. It involves direct integration of equations of grain system motion under the action of various forces, the most important of which are contact forces. The method’s accuracy depends mainly on precisely developed mathematical models of contacts. The creation of such models requires empirical validation, an experiment that investigates the course of contact forces at the moment of the impact of the grains. To achieve this, specialised test stations equipped with force and speed sensors were developed. The correct selection of testing equipment and interpretation of results play a decisive role in this type of research. This paper focuses on the evaluation of the force sensor dynamic properties’ influence on the measurement accuracy of the course of the plant grain impact forces against a stiff surface. The issue was examined using the computer simulation method. A proprietary computer software with the main calculation module and data input procedures, which presents results in a graphic form, was used for calculations. From the simulation, graphs of the contact force and force signal from the sensor were obtained. This helped to clearly indicate the essence of the correct selection of parameters used in the tests of sensors, which should be characterised by high resonance frequency.

Active Compensation Control of Wind Force and Wire Roughness for Current Collector Using Optical Fiber Sensor

1999 ◽  
Author(s):  
Kazuo Yoshida ◽  
Masaaki Ukita ◽  
Toshiaki Makino
Keyword(s):  
Control System ◽  
Optical Fiber ◽  
Active Control ◽  
Contact Force ◽  
Optical Fiber Sensor ◽  
Current Collector ◽  
Low Noise ◽  
Fiber Sensor ◽  
Noise Current ◽  
And Control

Abstract For railways speed up such as 350km/h, it is particularly important to reduce noise caused by current collector for environmental problem. For a solution, a diamond shaped low-noise current collector has been developed. However, it becomes difficult for the current collector to maintain the predetermined contact force between the contact strip and the trolley-wire. Therefore, it is necessary to apply the active control to keep the contact force uniform. However, there is a serious problem for the active control that it is difficult to put sensors in high voltage region. In this paper, an application of plastic optical fiber sensor is devised and it is applied to the control system. In the experiment, the usefulness of the proposed sensor and control system is demonstrated.

Complex Sparse-Filled Mechanical Property Prediction Methods for Direct Digital Manufacturing

2013 ◽  
Author(s):  
David N. Kordonowy ◽  
Sydney A. Giblin
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Flexible Manufacturing ◽  
Test Methods ◽  
Low Noise ◽  
Digital Manufacturing ◽  
Cycle Times ◽  
Mechanical Property Prediction ◽  
Direct Digital Manufacturing ◽  
And Control

This paper describes how direct digital manufacturing mechanical properties can be analytically estimated for structural use and the associated analytical and test methods used in the design and fabrication of airframes manufactured using additive manufacturing. Complex shape structures, which are now possible using additive manufacturing, and their associated mechanical properties can be predicted in order to allow operationally safe and highly predictive structures to be fabricated. Direct digital manufacturing allows for much greater flexibility and control over the design of airframes, leading to more structurally efficient and capable airframes. These advantages are revealed by application of direct digital manufacturing methods on a series of fixed wing subsonic transport concept wind tunnel scale models that are carried out as a part of the NASA N+3 program, which is paving the way for next generation aircraft that are highly fuel efficient, low-noise, and low-emission. Verification of these methods through test shows excellent correlation that provides reliability in complex sparse filled additive manufacturing design. The outcome of this is a knowledge base, which can then be applied to a system in operation. The combined potential of a flexible manufacturing system and proven predictive analysis tools shorten development time and expand the opportunities for mass customization. These combined benefits enable industry to fabricate affordable highly optimized custom products while concurrently reducing the cycle times required to field new products.

Design and Analysis of a Multimodal Grasper Having Shape Conformity and Within-Hand Manipulation With Adjustable Contact Forces

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Nagamanikandan Govindan ◽  
Asokan Thondiyath
Keyword(s):  
Control Strategies ◽  
Low Cost ◽  
Active Surface ◽  
Force Sensor ◽  
Contact Forces ◽  
Geometrical Shape ◽  
Planning And Control ◽  
Control Scheme ◽  
And Control ◽  
Compact Mechanism

Abstract This paper presents the design, analysis, and testing of a novel multimodal grasper having the capabilities of shape conformation, within-hand manipulation, and a built-in compact mechanism to vary the forces at the contact surface. The proposed grasper has two important qualities: versatility and less complexity. The former refers to the ability to grasp a range of objects having different geometrical shape, size, and payload and perform in-hand manipulations such as rolling and sliding, and the latter refers to the uncomplicated design, and ease of planning and control strategies. Increasing the number of functions performed by the grasper to adapt to a variety of tasks in structured and unstructured environments without increasing the mechanical complexity is the main interest of this research. The proposed grasper consists of two hybrid jaws having a rigid inner structure encompassed by a flexible, active gripping surface. The flexibility of the active surface has been exploited to achieve shape conformation, and the same has been utilized with a compact mechanism, introduced in the jaws, to vary the contact forces while grasping and manipulating an object. Simple and scalable structure, compactness, low cost, and simple control scheme are the main features of the proposed design. Detailed kinematic and static analysis are presented to show the capability of the grasper to adjust and estimate the contact forces without using a force sensor. Experiments are conducted on the fabricated prototype to validate the different modes of operation and to evaluate the advantages of the proposed concept.

Bonding, Defects, And Defect Dynamics In The Sic-SiO2 System

2000 ◽  
Vol 640 ◽  
Author(s):  
S. T. Pantelides ◽  
R. Buczko ◽  
M. Di Ventra ◽  
S. Wang ◽  
S.-G. Kim ◽  
...  
Keyword(s):  
First Principles ◽  
Oxidation Process ◽  
Atomic Scale ◽  
Contrast Imaging ◽  
Interface Defects ◽  
Device Applications ◽  
Z Contrast ◽  
And Control ◽  
Electron Energy Loss ◽  
Ultimate Purpose

ABSTRACTThis paper presents a review of new results obtained by a combination of first-principles theory, Z-contrast imaging, and electron-energy-loss spectroscopy in the context of a broader experimental/theoretical program to understand and control the atomic-scale structure of SiCSiO2 interfaces. The ultimate purpose is to achieve low interface trap densities for device applications. Results are given for global bonding arrangements in comparison with those of the Si-SiO2 interface, the mechanism of the oxidation process, the nature of possible interface defects and their passivation by N and H, and the formation and dissolution of C clusters in SiO2 during oxidation and reoxidation.

Influence of the Supplementary Cementitious Materials on the Dynamic Properties of Concrete

2014 ◽  
Vol 660 ◽  
pp. 162-167
Author(s):  
Elbachir Elbahi ◽  
Sidi Mohammed El Amine Boukli Hacene
Keyword(s):  
Dynamic Modulus ◽  
Dynamic Properties ◽  
Construction Materials ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Natural Pozzolan ◽  
Frequency Method ◽  
Concrete Mixtures ◽  
And Control ◽  
Non Destructive

The resonance frequency method is one of many non-destructive tests which allow us to evaluate construction materials. It was used to determine the dynamic properties of concrete, required in structures design and control, also considered as the key elements for materials dynamic. In this study, we chose a non-destructive approach to quantify-in laboratory-, the influence of adding “crushed limestone” and “natural pozzolan” on local concrete’s dynamic characteristics. However, several concrete mixtures have been prepared with limestone aggregates. The experimental used plan, allowed us to determine the dynamic modulus of elasticity, the dynamic modulus of rigidity of different formulated concretes.

Tractor Electro-Hydraulic Hitch System Design Based on DSP

2013 ◽  
Vol 448-453 ◽  
pp. 3481-3484
Author(s):  
Huang Xu ◽  
Yan Dong Song ◽  
Zhi Xiong Lu ◽  
Hong Lei Pang
Keyword(s):  
System Design ◽  
Force Sensor ◽  
Position Sensor ◽  
Hydraulic Control ◽  
Work Requirements ◽  
Hardware System ◽  
Sensor Position ◽  
Sensor Signals ◽  
Signal Output ◽  
And Control

To achieve electro-hydraulic control requirements of tractor hitch system, TMS320F2812 was chosen as control chip, to collect sensor signals and control the hitch system. Hardware system was designed to finish the signal collections of force sensor, position sensor and PWM signal output. Through the simulation, the reliability of design was verified, meeting the work requirements of electrohydraulic hitch system.

RNA granules and cytoskeletal links

2014 ◽  
Vol 42 (4) ◽  
pp. 1206-1210 ◽  
Author(s):  
Dipen Rajgor ◽  
Catherine M. Shanahan
Keyword(s):  
Mammalian Cells ◽  
Dynamic Properties ◽  
Translational Repression ◽  
Processing Bodies ◽  
P Bodies ◽  
Rna Granules ◽  
Messenger Ribonucleoprotein ◽  
Cytoskeletal Networks ◽  
And Control ◽  
Lower Eukaryote

In eukaryotic cells, non-translating mRNAs can accumulate into cytoplasmic mRNP (messenger ribonucleoprotein) granules such as P-bodies (processing bodies) and SGs (stress granules). P-bodies contain the mRNA decay and translational repression machineries and are ubiquitously expressed in mammalian cells and lower eukaryote species including Saccharomyces cerevisiae, Drosophila melanogaster and Caenorhabditis elegans. In contrast, SGs are only detected during cellular stress when translation is inhibited and form from aggregates of stalled pre-initiation complexes. SGs and P-bodies are related to NGs (neuronal granules), which are essential in the localization and control of mRNAs in neurons. Importantly, RNA granules are linked to the cytoskeleton, which plays an important role in mediating many of their dynamic properties. In the present review, we discuss how P-bodies, SGs and NGs are linked to cytoskeletal networks and the importance of these linkages in maintaining localization of their RNA cargoes.

An Analytical and Modular Software Workbench for Solving Kinematics and Dynamics of Series-Parallel Hybrid Robots

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Shivesh Kumar ◽  
Kai Alexander von Szadkowski ◽  
Andreas Mueller ◽  
Frank Kirchner
Keyword(s):  
Dynamic Modeling ◽  
Dynamic Properties ◽  
Weight Ratio ◽  
Robot Dynamics ◽  
Parallel Mechanisms ◽  
Modeling Tools ◽  
Closed Loops ◽  
Modular Software ◽  
Parallel Hybrid ◽  
And Control

Abstract Parallel mechanisms are increasingly being used as modular subsystem units in various robots and man-machine interfaces for their superior stiffness, payload-to-weight ratio, and dynamic properties. This leads to series-parallel hybrid robotic systems that are challenging to model and control due to the presence of various closed loops. Most model-based kinematic and dynamic modeling tools resolve loop closure constraints numerically and hence suffer from inefficiency and accuracy issues. Additionally, they do not exploit the modularity in robot design. In this paper, we present a modular and analytical approach toward kinematic and dynamic modeling of series-parallel hybrid robots. This approach has been implemented in a software framework called hybrid robot dynamics (hyrodyn) and its application is demonstrated with the help of a series-parallel hybrid humanoid robot recently developed at DFKI-RIC.

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