scholarly journals Development of a Compact Three-Degree-of-Freedom Laser Measurement System with Self-Wavelength Correction for Displacement Feedback of a Nanopositioning Stage

2018 ◽  
Vol 8 (11) ◽  
pp. 2209 ◽  
Author(s):  
Yindi Cai ◽  
Zhifeng Lou ◽  
Siying Ling ◽  
Bo-syun Liao ◽  
Kuang-chao Fan
Keyword(s):  
Laser Diode ◽  
Low Cost ◽  
Michelson Interferometer ◽  
Optical Path Difference ◽  
Path Difference ◽  
Degree Of Freedom ◽  
Laser Source ◽  
Laser Measurement ◽  
Length Unit ◽  
Three Degree Of Freedom

This paper presents a miniature three-degree-of-freedom laser measurement (3DOFLM) system for displacement feedback and error compensation of a nanopositioning stage. The 3DOFLM system is composed of a miniature Michelson interferometer (MMI) kit, a wavelength corrector kit, and a miniature autocollimator kit. A low-cost laser diode is employed as the laser source. The motion of the stage can cause an optical path difference in the MMI kit so as to produce interference fringes. The interference signals with a phase interval of 90° due to the phase control are detected by four photodetectors. The wavelength corrector kit, based on the grating diffraction principle and the autocollimation principle, provides real-time correction of the laser diode wavelength, which is the length unit of the MMI kit. The miniature autocollimator kit based on the autocollimation principle is employed to measure angular errors and compensate induced Abbe error of the moving table. The developed 3DOFLM system was constructed with dimensions of 80 mm (x) × 90 mm (y) × 20 mm (z) so that it could be embedded into the nanopositioning stage. A series of calibration and comparison experiments were carried out to test the performance of this system.

Design of a Teaching Robot with Three Degrees of Freedom

2012 ◽  
Vol 619 ◽  
pp. 325-328
Author(s):  
You Jun Huang ◽  
Ze Lun Li ◽  
Zhi Cheng Huang
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Degree Of Freedom ◽  
Good Repeatability ◽  
Main Components ◽  
Opening And Closing ◽  
Three Degree Of Freedom ◽  
Three Degrees Of Freedom ◽  
Application Prospects

A teaching robot with three degree of freedom is designed. The three degrees of freedom are: waist rotation, lifting and stretching of the arm and opening and closing of the gripper. The designs of the main components are: a mobile chassis, parallel rails, horizontal rails and manipulator. The teaching robot designed has the features of low cost, easy to regulation, good repeatability and it has good promotion and application prospects in the field of teaching.

Development of Near-Diffraction Limited, Low-Cost and High-Resolution CCD Camera System for Imaging Coulter Orifices

2014 ◽  
Vol 4 (2) ◽  
pp. 54-61
Author(s):  
Sami D. Alaruri
Keyword(s):  
Imaging System ◽  
Low Cost ◽  
Ccd Camera ◽  
Image Plane ◽  
Geometric Optic ◽  
Optical Path Difference ◽  
Path Difference ◽  
Modulation Transfer ◽  
Camera System ◽  
Micro Lens

A low-cost CCD camera system for imaging Coulter orifices ranging in diameter between 20 µm and 2 mm has been developed and tested. The imaging system incorporates a 6X magnifying lens for viewing the required range of Coulter orifices and LEDs (Light emitting diodes) lamp for back illuminating the orifices. Geometric optic calculations using Zemax® for the micro-lens interfaced with the camera suggest that the spot diameter and the MTF spatial frequency at field of view equal to 0 ° and at the image plane are 5.13 µm and 271.6 lines/mm (at contrast= 37.6%), respectively. Images captured with the camera system for 20 µm, 100 µm and 2 mm diameter orifices are provided. Furthermore, a discussion for the camera micro-lens modulation transfer function, spot diagram, root-mean-square wavefront error versus field and optical path difference plots is given.

scholarly journals THz Signal Generator Using a Single DFB Laser Diode and the Unbalanced Optical Fiber Interferometer

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4862
Author(s):  
Blaž Pongrac ◽  
Denis Đonlagic ◽  
Matej Njegovec ◽  
Dušan Gleich
Keyword(s):  
Optical Fiber ◽  
Laser Diode ◽  
Optical Signal ◽  
Optical Path Difference ◽  
Sweep Rate ◽  
Path Difference ◽  
Optical Path ◽  
Signal Generator ◽  
Optical Frequency ◽  
Frequency Sweep

This paper presents a frequency-modulated optical signal generator in the THz band. The proposed method is based on a fast optical frequency sweep of a single narrowband laser diode used together with an optical fiber interferometer. The optical frequency sweep using a single laser diode is achieved by generating short current pulses with a high amplitude, which are driving the laser diode. Theoretical analysis showed that the modulation frequency could be changed by the optical path difference of the interferometer or optical frequency sweep rate of a laser diode. The efficiency of the optical signal generator with Michelson and Fabry–Perot interferometers is theoretically analyzed and experimentally evaluated for three different scenarios. Interferometers with different optical path differences and a fixed optical frequency sweep rate were used in the first scenario. Different optical frequency sweep rates and fixed optical path differences of the interferometers were used in the second scenario. This paper presents a method for optical chirp generation using a programmable current pulse waveform, which drives a laser diode to achieve nonlinear optical sweep with a fixed optical path difference of the interferometer. The experimental results showed that the proposed signals could be generated within a microwave (1–30 GHz) and THz band (0.1–0.3 THz).

Improved Development Cycle of a Compliant Manipulator

2003 ◽  
Author(s):  
Stephen L. Canfield ◽  
Patrick V. Hull ◽  
James W. Beard
Keyword(s):  
Design Process ◽  
Design Methodology ◽  
Low Cost ◽  
Parallel Architecture ◽  
Degree Of Freedom ◽  
Modeling Tools ◽  
Multiple Features ◽  
Positioning Accuracy ◽  
Development Cycle ◽  
Three Degree Of Freedom

Application of the compliant design methodology to manipulators has held the promise of delivering manipulators with many significant advantages, including low cost, small size, low backlash and friction, and high positioning accuracy. This approach has been demonstrated in part by Canfield et. al., [1] to a class of three-degree-of-freedom manipulators based on a specific parallel architecture topology. In [1], the authors’ intent was to develop two compliant manipulators that exhibit several of the features associated with compliant devices. However, upon review of the manipulators resulting from this work it is observed that many of the benefits that were expected were lost at some point in the design process, resulting in manipulators that were large, expensive and suffered significantly from required assembly and inaccuracies in manufacture. This paper will revisit the problem addressed in [1], using the modeling tools demonstrated in that paper but will present several improved development measures that will result in manipulators that exhibit multiple features promised by compliant devices. The resulting manipulators will then be compared against the manipulators from [1] with a summary of the performance and characteristics of each given and evaluated.

scholarly journals Real-Time Correction and Stabilization of Laser Diode Wavelength in Miniature Homodyne Interferometer for Long-Stroke Micro/Nano Positioning Stage Metrology

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4587 ◽  
Author(s):  
Yindi Cai ◽  
Baokai Feng ◽  
Qi Sang ◽  
Kuang-Chao Fan
Keyword(s):  
Real Time ◽  
Laser Diode ◽  
Low Cost ◽  
Displacement Measurement ◽  
Laser Source ◽  
Wavelength Stabilization ◽  
Positioning Stage ◽  
Drift Compensation ◽  
Optical Configuration ◽  
Long Stroke

A low-cost miniature homodyne interferometer (MHI) with self-wavelength correction and self-wavelength stabilization is proposed for long-stroke micro/nano positioning stage metrology. In this interferometer, the displacement measurement is based on the analysis of homodyne interferometer fringe pattern. In order to miniaturize the interferometer size, a low-cost and small-sized laser diode is adopted as the laser source. The accuracy of the laser diode wavelength is real-time corrected by the proposed wavelength corrector using a modified wavelength calculation equation. The variation of the laser diode wavelength is suppressed by a real-time wavelength stabilizer, which is based on the principle of laser beam drift compensation and the principle of automatic temperature control. The optical configuration of the proposed MHI is proposed. The methods of displacement measurement, wavelength correction, and wavelength stabilization are depicted in detail. A laboratory-built prototype of the MHI is constructed, and experiments are carried out to demonstrate the feasibility of the proposed wavelength correction and stabilization methods.

Control System Design for AC-DC Three-Degree-of-Freedom Hybrid Magnetic Bearing

2012 ◽  
Vol 150 ◽  
pp. 144-147 ◽  
Author(s):  
Wei Yu Zhang ◽  
Ying Ruan ◽  
Xiao Yan Diao ◽  
Huang Qiu Zhu
Keyword(s):  
Control System ◽  
System Design ◽  
High Speed ◽  
Manufacturing Industry ◽  
Block Diagram ◽  
Low Cost ◽  
Magnetic Bearing ◽  
Degree Of Freedom ◽  
Control System Design ◽  
Three Degree Of Freedom

To fulfil the objective of high speed, high precision and intelligence in the modern equipment and advanced manufacturing industry, the magnetic bearing is requested to have small volume, low cost and low consumption. In this paper, an AC-DC three-degree-of-freedom hybrid magnetic bearing (AC-DC-3DOF-HMB) is studied, which integrates radial bearing and axial bearing in one of the magnetic bearing. The configuration and principle of AC-DC-3DOF-HMB are expounded, and the mathematical models of suspension forces are given. Then based on the function block diagram of AC-DC-3DOF-HMB control system, its hardware and software configuration are designed. The experiment results show that the rotor can be suspended stably with three degrees of freedom and has a good performance in anti- interference, and the feasibility of the control system design can be verified.

scholarly journals The Influence of Fiber Cross-Section on Fabric Far-Infrared Properties

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1147 ◽  
Author(s):  
Yifei Tao ◽  
Tenghao Li ◽  
Chenxiao Yang ◽  
Naixiang Wang ◽  
Feng Yan ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Far Infrared ◽  
Cost Effective ◽  
Optical Path Difference ◽  
Path Difference ◽  
Environmental Stability ◽  
Theoretical Simulation ◽  
Circular Fiber ◽  
Facile Fabrication

Far-infrared radiation (FIR) possesses various promising properties that are beneficial to an individuals’ health. Exploring the interaction between fiber shapes and FIR performance is thought to be a significant means to develop highly-efficient FIR textile products. In this study, a non-additive triangular polyamide (PA) fiber showed excellent FIR properties in both theoretical simulation and experimental verification aspects. The triangular PA fiber affords a higher probability to facilitate large optical path difference, improving both FIR absorption and emission. Textiles woven with the specific triangular PA fiber achieved a remarkable emissivity of 91.85% and temperature difference of 2.11 Celsius, which is obviously superior to the reference circular fiber (86.72%, 1.52 Celsius). Considering the low cost, environmental stability, facile fabrication, as well as being environmentally friendly, this non-additive triangular PA fiber has great potential for high-performance and cost-effective FIR textiles in the future.

Floor Vibration Control Using Three-Degree-of-Freedom Tuned Mass Dampers

2004 ◽  
Author(s):  
Khalid I. Al-Hulwah ◽  
Reza Kashani
Keyword(s):  
Building Materials ◽  
Low Cost ◽  
Heavy Traffic ◽  
High Strength ◽  
Degree Of Freedom ◽  
Tuned Mass Dampers ◽  
Floor Vibration ◽  
Normal Human ◽  
High Level ◽  
Three Degree Of Freedom

The use of high-strength material in buildings has resulted in the use of less building materials and, consequently, a high level of flexibility in buildings, making them vibration prone. For example, high-strength concrete has lowered the thickness of concrete slabs used in the floors of steel/concrete buildings, such as office buildings and shopping centers, resulting in excessive floor vibration stemming from heavy traffic and normal human activity. Although not dangerous, such vibration is highly annoying to the occupants of the building. The authors have been working on the use of three-degree-of-freedom (3-DOF) tuned mass dampers (TMD) to abate floor vibration. Such TMDs can provide improved effectiveness over a traditional one-degree-of-freedom TMD and yet possess all of the attractive features of a traditional TMD; namely, simplicity and low cost. As in a 1-DOF TMD, this device will be installed on a concrete floor slab, at an optimally designed/chosen location.

scholarly journals Megahertz scan rates enabled by optical sampling by repetition-rate tuning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
D. Bajek ◽  
M. A. Cataluna
Keyword(s):  
Real Time ◽  
Repetition Rate ◽  
Low Cost ◽  
Impedance Matching ◽  
Michelson Interferometer ◽  
Laser Source ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Optical Sampling ◽  
Probe Spectroscopy

AbstractWe demonstrate, for the first time, optical sampling by repetition-rate tuning (OSBERT) at record megahertz scan rates. A low-cost, tunable and extremely compact 2-section passively mode-locked laser diode (MLLD) is used as the pulsed laser source, whose repetition rate can be modulated electronically through biasing of the saturable absorber section. The pulsed output is split into two arms comparable to an imbalanced Michelson interferometer, where one arm is significantly longer than the other (a passive delay line, or PDL). The resulting electronic detuning of the repetition rate gives rise to a temporal delay between pulse pairs at a detector; the basis for time-resolved spectroscopy. Through impedance-matching, we developed a new system whereby a sinusoidal electrical bias could be applied to the absorber section of the MLLD via a signal generator, whose frequency could be instantly increased from sub-hertz through to megahertz modulation frequencies, corresponding to a ground-breaking megahertz optical sampling scan rate, which was experimentally demonstrated by the real-time acquisition of a cross-correlation trace of two ultrashort optical pulses within just 1 microsecond of real time. This represents scan rates which are three orders of magnitude greater than the recorded demonstrations of OSBERT to date, and paves the way for highly competitive scan rates across the field of time-resolved spectroscopy and applications therein which range from pump probe spectroscopy to metrology.

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