Optical Control System Research Articles

Design of PCB Automatic Optical Defect Detection and Control System Based on PLC

This paper introduces the automatic optical defect detection and control system of the array camera PCB with PLC as the core and gives the PID control of the PCB motion device, the area camera and the Kalman filter. According to the set process conditions of the industrial assembly line, the whole system is controlled to acquire the defect detection image of the PCB. Compared with the scanning of the line camera, the image acquisition time is reduced, and the detection efficiency is improved.

Design of a multiband near-infrared sky brightness monitor using an InSb detector.

Infrared sky background level is an important parameter of infrared astronomy observations from the ground, particularly for a candidate site of an infrared capable observatory since low background level is required for such a site. The Chinese astronomical community is looking for a suitable site for a future 12 m telescope, which is designed for working in both optical and infrared wavelengths. However, none of the proposed sites has been tested for infrared observations. Nevertheless, infrared sky background measurements are also important during the design of infrared observing instruments. Based on the requirement, in order to supplement the current site survey data and guide the design of future infrared instruments, a multiband near-infrared sky brightness monitor (MNISBM) based on an InSb sensor is designed in this paper. The MNISBM consists of an optical system, mechanical structure and control system, detector and cooler, high gain readout electronics, and operational software. It is completed and tested in the laboratory. The results show that the sensitivity of the MNISBM meets the requirements of the measurement of near-infrared sky background level of several well-known astronomical infrared observing sites.

高精度大范围的光学晶体温度控制系统

高精度大范围的光学晶体温度控制系统

Enhanced intrinsic CYP3A4 activity in human hepatic C3A cells with optically controlled CRISPR/dCas9 activator complex.

Human hepatic C3A cells have been applied in bioartificial liver development, although these cells display low intrinsic cytochrome P450 3A4 (CYP3A4) enzyme activity. We aimed to enhance CYP3A4 enzyme activity of C3A cells utilizing CRISPR gene editing technology. We designed two CYP3A4 expression enhanced systems applying clustered regularly interspaced short palindromic repeats (CRISPR) gene technology: a CRISPR-on activation system including dCas9-VP64-GFP and two U6-sgRNA-mCherry elements, and a light-controlled CRISPR-on activation system combining our CRISPR-on activation system with an optical control system to facilitate regulation of CYP3A4 expression for various applications. Results of enzymatic activity assays displayed increased CYP3A4 activity in C3A cells expressing the CRISPR-on activation system compared with C3A cells. In addition, CYP3A4 activity increased in C3A cells expressing the light-controlled CRISPR-on activation system under blue light radiation compared with C3A cells. Notably, there was no statistical difference in the increase of CYP3A4 protein amounts induced by these two methods. After expansion in culture, C3A cells with the light-controlled CRISPR-on activation system exhibited no statistical difference in CYP3A4 mRNA levels between generations. Our findings provide a method to stably enhance functional gene expression in bioartificial liver cells with the potential for large-scale cell expansion.

Virtual velocity loop based on MEMS accelerometers for optical stabilization control system

In the optical stabilization control system (OSCS) control system based on a charge-coupled device (CCD), stabilization performance of the line-of-sight is severely limited by the mechanical resonance and the low sampling rate of the CCD. An approach to improve the stabilization performance of the OSCS control system with load restriction based on three loops, including an acceleration loop, a virtual velocity loop, and a position loop, by using MEMS accelerometers and a CCD is proposed. The velocity signal is obtained by accelerators instead of gyro sensors. Its advantages are low power, low cost, small size, and wide measuring range. A detailed analysis is provided to show how to design the virtual velocity loop and correct virtual velocity loop drift. Experimental results show that the proposed multiloop feedback control method with virtual velocity loop in which the disturbance suppression performance is better than that of the dual loop control with only an acceleration loop and a position loop at low frequency.

Real Time Film Inspection

OCS Optical Control Systems is manufacturing production-integrated film inspection systems. Machine vision components from Stemmer Imaging make up the optical solution.

Effect of magnetic fields on green color formation in frog skin

The present work is focused on a dynamic and efficient optical control system that is made possible by investigation of the body surfaces of various animals. Specifically, we expect Japanese tree frog (Hyla japonica) skin to provide a model for a flexible display device actuator mechanism. Tree frogs change body color from their original green to other colors in response to background colors. The color formation is controlled not only by chromatophores, but also by guanine microcrystals in iridophores. We collected sample microcrystals from the frog’s dorsal skin and made a model display sheet using the green skin layers. The transparent chamber that contained the crystal suspension was layered to enhance light reflection. Sheet color was observed while the angle of light incidence was varied, with and without magnetic field exposure at 0.3 T. A slight increase in red and green intensity was detected. Additionally, reflected intensity increased with increasing angle of incidence. These results indicate that the guanine crystal platelets in frog skin can efficiently switch the reflected light direction under application of a magnetic field. This in turn suggests that a several-micron-sized microcrystal of this type is a candidate material for development of flexible optical chips for ambient light control.

Mechanical means for controlling the geometry of optical spacecraft attitude control systems and the necessary accuracy of these means

The accuracy of modern spacecraft attitude sensors has recently come to exceed the accuracy provided by the rigidity of the mechanical designs of spacecraft. One possible solution to this problem is to introduce additional sensors measuring the mutual orientation of the attitude sensors into the design of attitude control systems. In this paper we consider the questions of whether the simplest and most reliable mechanical distance measurement sensors can be used and whether their accuracy is sufficient for this purpose.

Adaptive Integrated Optical Bragg Grating in Semiconductor Waveguide Suitable for Optical Signal Processing

ABSTRACTThis article presents a methodology for an integrated Bragg grating using an alloy of GaAs, AlGaAs, and InGaAs with a controllable refractive index to obtain an adaptive Bragg grating suitable for many applications on optical processing and adaptive control systems, such as limitation and filtering. The refractive index of a Bragg grating is controlled by using an external electric field for controlling periodic modulation of the refractive index of the active waveguide region. The designed Bragg grating has refractive indices programmed by using that external electric field. This article presents two approaches for designing the controllable refractive indices active region of a Bragg grating. The first approach is based on the modification of a planar micro-strip structure of the iGaAs traveling wave as the active region, and the second is based on the modification of self-assembled InAs/GaAs quantum dots of an alloy from GaAs and InGaAs with a GaP traveling wave. The overall design and results are discussed through numerical simulation by using the finite-difference time-domain, plane wave expansion, and opto-wave simulation methods to confirm its operation and feasibility.

The cost optimal control system based on the Kermack–Mckendrick worm propagation model

Although the network worm propagation models are able to predict trends in the spread of the worm, these papers did not consider the economic losses caused by the worm propagation. This paper uses the Hamiltonian approach of the optimal control theory and proposes the cost optical control system based on the Kermack–Mckendrick worm propagation model. In the cost optical control system, we control and process the infectious hosts. In this paper, we present an optimization model that takes into account infection cost and treatment cost. The simulation on the cost optical control system is carried out, and then the results of the analysis are given. In conclusion, the cost optical control system of the Kermack–Mckendrick model can provide the optical control of the worm propagating and effectively reduce the worm propagation with minimum cost.

Automatic alignment and testing system for wafer with ball grid array

In order to develop automatic testing system for wafer with ball grid array, a method of pattern matching using the feature of ball grid array is proposed, and a new testing system with optical system and motion control system is integrated. It was found that the accurate position of wafer can be found before wafer probe testing, and the relative position between probe array and every chip can be calculated. The wafer can be aligned precisely by image process and motion control. Results show that the automatic testing of wafer can be carried out, and the electrical properties of the chip can be effectively evaluated.

Holographic fiber bundle system for patterned optogenetic activation of large-scale neuronal networks.

Optogenetic perturbation has become a fundamental tool in controlling activity in neurons. Used to control activity in cell cultures, slice preparations, anesthetized and awake behaving animals, optical control of cell-type specific activity enables the interrogation of complex systems. A remaining challenge in developing optical control tools is the ability to produce defined light patterns such that power-efficient, precise control of neuronal populations is obtained. Here, we describe a system for patterned stimulation that enables the generation of structured activity in neurons by transmitting optical patterns from computer-generated holograms through an optical fiber bundle. The system couples the optical system to versatile fiber bundle configurations, including coherent or incoherent bundles composed of hundreds of up to several meters long fibers. We describe the components of the system, a method for calibration, and a detailed power efficiency and spatial specificity quantification. Next, we use the system to precisely control single-cell activity as measured by extracellular electrophysiological recordings in ChR2-expressing cortical cell cultures. The described system complements recent descriptions of optical control systems, presenting a system suitable for high-resolution spatiotemporal optical control of wide-area neural networks in vitro and in vivo, yielding a tool for precise neural system interrogation.

The optical control system of dispersed phase properties in thermal spray process

The models of measuring the velocity and temperature of particles using the processing of their track images are introduced. The method of brightness pyrometry of moving objects uses the calibration procedure based on the static temperature standard. Performance of the statistical analysis of thermal data by means of optical control system of the particles properties in gas-thermal spraying flow equals to 2200-2700 particles per second. Investigation of stationary plasma spraying process allowed to obtain the distributions of velocity and temperature of particles over the volume of spraying jet. The error in determining the velocity of the particles was 1%, and the error in determining the temperature is 3%.

Graphene/Phase Change Material Nanocomposites: Light-Driven, Reversible Electrical Resistivity Regulation via Form-Stable Phase Transitions

Innovative photoresponsive materials are needed to address the complexity of optical control systems. Here, we report a new type of photoresponsive nanomaterial composed of graphene and a form-stable phase change material (PCM) that exhibited a 3 orders of magnitude change in electrical resistivity upon light illumination while retaining its overall original solid form at the macroscopic level. This dramatic change in electrical resistivity also occurred reversibly through the on/off control of light illumination. This was attributed to the reversible phase transition (i.e., melting/recrystallization) behavior of the microscopic crystalline domains present in the form-stable PCM. The reversible phase transition observed in the graphene/PCM nanocomposite was induced by a reversible temperature change through the on/off control of light illumination because graphene can effectively absorb light energy and convert it to thermal energy. In addition, this graphene/PCM nanocomposite also possessed excellent mechanical properties. Such photoresponsive materials have many potential applications, including flexible electronics.

Design of Electronic Control System for HCCI Optical Engine and Optical Testing

An optical engine system have been designed which can realize the goal of spark ignition and homogeneous charge compression ignition. This system consists of an optical engine and an electric control system. We have measured temperature in cylinder and molar coefficient of the main material (CO2, O2, N2, H2O, fuel) which has a resolution of nanosecond level and millimeter level. To realize the visualization in cylinder, extended pistons, extended cylinder liner and extended cylinder body have been designed and all of them have optical window. To realize the path of laser, a ring gasket of the laser window has been added between the original cylinder head and the extended cylinder body. An optical engine electronic control system based on SCM 80C196 has been designed to make the optical engine work in different testing strategies. The experimental results show the optical engine work well under the control of electric control system and we can detect optical Raman spectroscopy in the optical engine.

Nanosecond transient electric field measurement system using an integrated electro-optic sensor

A lithium niobate optical waveguide-based integrated electro-optic (EO) electric field ( E -field) sensor dedicated to the measurement of intense nanosecond transient electromagnetic pulse (EMP) signals has been developed and calibrated. The time domain calibration system for measurement of intense nanosecond EMP signals has been established. A pure optical bias phase angle control system based on wavelength tuning has been developed and implemented to ensure that the sensor has a linear transfer function. The fluctuations of the sensor static output optical power are with the proposed bias control system while without bias control. The time domain characteristics of the detected pulsed E -fields have been compared with those of the input EMP signals. For the first type nanosecond level (ns-level) EMP signal, the relative errors of the detected E -fields on rise time, fall time, and pulse width are 0.38%, 0.69%, and 0.79%, respectively. Also, for the second type ns-level EMP signal, the relative errors of the measured E -fields on rise time, fall time, and pulse width are 0.40%, 0.31%, and 0.01%, respectively. All these results demonstrate that the developed integrated EO E -field sensing system has the potential to be used to accurately extract the information of transient E -fields.

The Optical Path Closed-Loop Control System

The optical path closed-loop control system mainly applies to large high power equipment that makes the optical path adjust automatically. The paper introduces the principle of optical path closed-loop system. In addition, it introduces the laser spot recognition algorithm and the PC real-time monitoring system. After the test, the system not only can accurately calculate the position of spot, but also realize the monitoring and adjustment of spot.

High-resolution fiber-fed echelle spectrograph for the 6-m telescope. I. Optical scheme, arrangement, and control system

We propose a project of a high-resolution (R = 100 000) fiber-fed spectrograph for comprehensive studies of stellar atmospheres, exoplanet searches, asteroseismological studies, studies of stellar magnetism, active nuclei of bright galaxies, interstellar medium, etc. We present the optical scheme of the instrument. The operating wavelength region spans from 4000 to 7500 A. We also present the optical scheme of the pre-fiber optic unit of the spectrograph. The unit supports four main modes of spectroscopic observations: the mode of traditional spectroscopy with the spectrum of the studied object taken along with the background spectrum in the immediate vicinity of the object; the mode of the simultaneous recording of the spectrum of the object and that of the wavelength standard; the mode of high-precision spectroscopy with an iodine cell, and the mode of spectropolarimetric observations with the measurement of all the Stokes parameters.

Three biomimetic flight control sensors

Purpose– Insects depend on the spatial, temporal and spectral distribution of light in the environment for navigation, collision avoidance and flight control. The principles of insect vision have been gradually revealed over the course of decades by biological scientists. The purpose of this paper is to report on bioinspired implementations and flight tests of these sensors and reflexes on unmanned aerial vehicles (UAVs). The devices are used for the stabilization of UAVs in attitude, heading and position. The implementations were developed to test the hypothesis that current understanding of insect optical flight control systems is feasible in real systems.Design/methodology/approach– Design was based on behavioral and anatomical studies of insects. The approach taken was to test the designs in flight on a UAV.Findings– The research showed that stabilization in attitude, heading and position is possible using the developed sensors.Practical implications– Partial alternatives to magnetic, inertial and GPS sensing have been demonstrated. Optical flow and polarization compassing are particularly relevant to flight in urban environments and in planetary exploration.Originality/value– For the first time the use of multispectral horizon sensing, polarization compassing and optical flow-based heading control have been demonstrated in flight.

High-performance optical modulators bias control system without dither

A software-based bias control system of push–pull Mach–Zehnder modulators (MZMs) without dither tone is described in this paper. The slope of the average optical output power respect to the bias voltage is used to control the operating bias points in the automatic control system. The paper analyses the theory of automatic bias control intensively and verifies the effectiveness of the proposed technique which is a modulation-format-free method under the RF signal through testing and contrasting the BER (bit error rate) between the new technique and manual measure on the experimental platform. Based on this, an automatic bias control system set up by an optical QPSK composed by double MZMS on the LabVIEW platform is described.