Chinese Version Light学术出版中心
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Issue 2 ， 2002
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Design on the athermal infrared diffractive/refractive optical system in 3.2～4.5μm
Abstract：Based on the investigation on the thermal properties of the diffractive lens, the paper introduces a method and some examples for designing the athermal diffractive/refractive optical system in the infrared region. An optical system at 3.2～4.5μm with 100% cold shield efficiency, 5-degree field of view was designed, associated with high optical quality at the temperature ranging from -40℃ to 80℃. With this designing scheme, there is decrease in the number of optical components for a conventional optical system by one piece, and the weight can be reduced by 1/4, and expensive Se-Zn IR material is saved. Furthermore, the image quality approaching the diffraction limit in a larger spatial field view and wider thermal range can be obtained.Keywords：infrared optical systems;diffractive optics;athermal systems- 51
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Published：2020-08-12 -
Design on a fly lens array illumination system applied in LC rear projective TV
Abstract：Based on analyzing the LC rear projective TV system, a fly-eye lens array illumination system has been designed, which can magnificently improve the optical performance. The modeled result by means of the Light Tools software shows that the uniformity can reach +5.07%, -8.62%, and the effective energy can be above 70%. This paper also explicates the computer modeling based on the actual light source, and presents the design method and cases.Keywords：liquid crystal rear projective TV;fly-eye lens arrays;light source modeling;optical design- 92
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Published：2020-08-12 -
Investigation on a laser Doppler velocimetry signal processor based on PC
Abstract：A new Doppler signal processor used in a LDA system is introduced, where the photoelectric signals are processed on the basis of the power spectrum method by a personal computer(PC). The hardware of the processor is mainly composed of filters, a burst detector, an A/D converter, a RAM and the arriving-moment recorder of burst. The effective Doppler voltage giving the moving velocity of scatter can be extracted from the photoelectrical signal and digitized with the hardware. A PC gathers the digital data through the interface and carries out FFT to get the flowing information of the field. In order to optimize the noise rejection properties of the processor, such techniques as zero-filling, adding windows and zooming were employed. A practical application shows the ability of tracing the turbulent velocities. The processor has the advantages of fine performance, simple structure and low cost. With the development of PC, this kind of LDA signal processing method is sure to have better prospects in the future.Keywords：laser Doppler velocimetry;average periodic diagrams;Doppler signal processing- 49
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Published：2020-08-12 -
Load detection and fuzzy control in the power ultrasonic system
Abstract：To acquire approved ultrasonic emulsification effects while using the power ultrasonic medical treatment instrument to cure patients, an ultrasonic vibration system is always needed to operate at a high vibration amplitude under different load conditions and to work in the electormechanical matching state under all load conditions. Firstly, the paper focuses on the equivalent electromechanical model to the power ultrasonic vibration system made up of a longitudinal composite-bar high-power transducer, a horn and a scalpel. Secondly, depending on the model, it analyzes the fundamental principles of dynamic impendence matching in the power ultrasonic vibration system. At the same time, according to the operating characteristics of the system, an approach to dynamic impedance on-line detecting has been devised and the parameters reflecting load state and change trend are obtained. Based on the identified dynamic load, the input and output parameters of the fuzzy controller can be determined.Finally, it presents an applied fuzzy control algorithm, which can be used as a dynamic impedance matching approach for the power ultrasonic vibration system. The experiment results show that when the power ultrasonic vibration system operates at the state of dynamic impedance matching by using the fuzzy control technique, the system can always have high electric power and good effects of the ultrasonic emulsification under the changing load.Keywords：Fuzzy control;Detection;electric power;impedance matching- 44
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- 2
Published：2020-08-12 -
Hindle testing of the off-axis convex ashpere surface
Abstract：Hindle testing of the convex aspherical surface is one of the classical methods, which has the advantages of high accuracy and easy operation. In order to avoid the large aperture of Hindle ball when an off-axis convex aspherical surface is under testing, the authors suggest that it be done with off-axis Hindle ball. Hindle ball is used in off-axis configuration, at the same time it can be rotated so that the whole area can be tested. The size of Hindle ball can be reduced, thus the area in the aspherical surface to be tested is increased. The accuracy of the method is also analyzed theoretically.Keywords：aspherical surface testing;off-axis;Hindle testing- 55
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Published：2020-08-12 -
Dynamic analysis on a novel nanopositioning stage driven by PZT
Abstract：A novel nanometric precision two-degrees-of-freedom positioner driven by PZT was designed and fabricated.The theoretical and experimental analyses of the stage performance were also done.The nanopositioning stage consists of a right-angle flexure parallel hinge to realize the motion along X and Y directions and the flexure pivoted lever arm to achieve piezoactuator displacement amplification. The differential equation of motion was established by Lagrange equation, and the expression of the two mode nature frequencies were derived. The model analysis of the stage was carried out by means of ANSYS, a Finite Element Method (FEM) code. Experiments were conducted to measure the modal frequencies of the stage. The results obtained from formulation, Finite Element Method(FEM) and experiments were analyzed. The numerical and experimental results prove the accuracy of the theoretical model and the validity of the FEM analysis.Keywords：Nano-positioning;flexure hinges;finite element analysis- 47
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Published：2020-08-12 -
Multi-robot path planning-oriented and fuzzy model-based reinforcement function structures
Abstract：As a newly rising intelligent learning mode, reinforcement learning is being applied more and more in a learning system with unknown environment model because of its simple learning mechanism and no need of knowledge of the system or sample data in advance. However, one of the problems of the reinforcement learning method is that its learning speed is too low to ensure the real-time system. Researchers have studied to speed up learning by improving learning algorithm and adopting intelligent exploration policy or applying the hierarchical reinforcement learning method, etc. However, how to describe the reinforcement function and how the reinforcement function affects the learning speed are seldom studied. In the existing reinforcement learning system, the model-free reinforcement function artificially defined is usually used. Its simple and rough expression is one of the causes of the low efficiency of learning. In this article, a new fuzzy model-based reinforcement function structure is presented. It is described according to the actual application in the conflict-free path planning problem of a cooperative multiple mobile robot system. In this system, the robot behaviors are divided into three basic kinds moving to the goal, avoiding obstacles and other robots. Then, the subfunctions reflecting these basic behaviors of robots are hierarchically and fuzzily modeled, and the final reinforcement function is expressed by the sum of fuzzy weighted sub-functions. The fuzzy model based reinforcement function has more accurate expression of the influence of each robot’s action on the environment. The simulation shows that using the fuzzy model based reinforcement functions in reinforcement learning algorithm can further speed up the convergence than using model-free reinforcement functions.- 61
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Published：2020-08-12 -
Key technologies and applications of micromechanical inertial measurement units
Abstract：The development of the micromechanical inertial measurement unit and its applications are briefly overviewed in this paper. Based on its current technological development status in China, the main problems and key techniques are discussed from an applicable viewpoint. Finally, a suitable way of developing the micro-mechanical inertial measurement system is suggested.Keywords：micromechanical gyroscopes;micromechanical accelerometers;micromachanical inertial measurement units- 43
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Published：2020-08-12 -
Motion characteristics of earthworm-based miniature robotic components
Abstract：In this paper an earthworm-based miniature robotic endoscope prototype is put forward, and the structure and driving principles of the robot are introduced, and still the motion characteristics of each component are discussed as well. The motion of the miniature robot can be controlled effectively by adjusting the driving waveform. The relationship between driving time of the component and the displacement, velocity and acceleration is illustrated in detail, and thus the maximum driving frequency is determined. The velocity of the miniature robot can be adjusted by adjusting the driving frequency and the heat generation is reduced by shortening the driving time. The research has laid foundation for the application of the miniature robotic endoscope.Keywords：miniature robots;endoscopes;driving principles;motion characteristics- 50
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- 2
Published：2020-08-12 -
Research on three reliability distribution methods of an industrial robot system
Abstract：The prospect and quality of industrial robots depend on their reliability. However, the reliability of industrial robots in China needs improving. In this paper, three ways of making reliable distribution are put forward for industrial robot systems. The least effort and proportion distribution method is suitable for the industrial robot system that has been newly made, and it has been put in use and put in production to enhance its reliability. The mixed distribution method is a simple way of reliability distribution of an industrial robot system. It is fit for making system reliability distribution in the development of new industrial robots and without restrictions to achieve high reliability. The two-level optimizing distribution method is a reliability optimizing distribution method with restriction. Researches on these three reliability distribution methods of industrial robot systems as a critical part in the reliability design not only has a theoretical research value, but also has an important and practical value.Keywords：industrial robots;two-layer strategies;two-level optimizing distribution method- 54
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Published：2020-08-12 -
Some issues on the micro-vision system for a micromanipulation robot
Abstract：The micro-vision system is an important part of a micromanipulation robot. In recent years, with the development of micro-techniques, the study of micro-vision has become a focus. This paper introduces its significance and status in research fields at home and abroad, and discusses some key problems to be solved immediately and their solutions. It also predicts the outlook and trends of the micro-vision system.Keywords：robots;Micromanipulation;micro-vision;microscopes- 79
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Published：2020-08-12 -
Application of the 6K6 serial multi-axis-movement-controller in laser resistance trimmers
Abstract：The movement-controlling system in the micro-electronic equipment is one of the most important units, which influences its manufacturing quality and efficiency. It has many characteristics such as high precisioin, high speed, high efficiency and reliability. Especially, when its hardwares encounter any breakdowns or wrong operation, the self-examination and self-diagnosis of the system become more important. 6K6 multi-axis controller is the movement-controlling system kernel of a laser trimming system, which can control 8 axes at most through agility programmers. This paper introduces the design and control of the speed and location precision of the linear servo motor, alternative-current servo motor, directive-current servo motor by adopting 6K6 multi-task real-time controller according to the way of event-drive-response, control of on/off of the electric valve of the pneumatic kits to make the mechanical arms run smoothly through the export interface module, and supervision of many kinds of sensors through the import interface module, which endows the movement system with more reliability, higher precision and super high speed, and realizes auto-feeding of products and finishes all relative movements in production. The technology is useful for reducing the cost, enhancing the equipment efficiency and competition power, and promises large-scale production. It has filled the gap domestically.Keywords：laser trimmers;multi-task real-time controllers;motor drivers- 44
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Published：2020-08-12 -
Study of the MSB information-hiding technique in a carrier image
Abstract：Encryption technique is an important method to ensure safe communication, but it has a shortcoming. Because the files encrypted are vulnerable to attackers, they may be destroyed.To solve the problem, the authors take advantages of the encryption technique and information-hiding technique, i.e. concealing the information encrypted into a carrier file. The authors adopts color image files being used in the Internet. If human eyes can not observe the diversifications of the carrier image before and after hiding, the method can be very safe.As far as the authors know, there are two kinds of encryption techniques. One is based on frequency region, such as expanding frequency hiding, DCT hiding and sub-wave hiding, etc. By these methods the information is concealed into the high frequency heft of the carrier image code, which can not be observed by human eyes. Generally speaking, not much data can be concealed into a carrier image. The other is based on space region, a typical method to conceal information in the least significance bits (LSB); however, due to their unsafety, they are not important to the carrier image. This paper provides a method that can create redundant space in a color image by color quantization and hiding information in the MSB of the image. The method is better than that in LSB since the MSB is very important to the visual effect of the image.Keywords：information hiding;color quantization;carrier image- 63
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Published：2020-08-12 -
MHMM-based computed radiography image-denoising method
Abstract：In the process of computed radiography imaging, a lot of noises will be brought into the system. Therefore, only by knowing their resources, characteristics and relationship with signals, can the authors smooth them. On the basis of analyzing the computed radiography system in detail, the authors point out that there are two kinds of noises affecting the quality of a computed radiography image: Gaussian white noise and Poisson noise. Firstly, the statistical characteristics of wavelet coefficients and Gaussian white noise are summarized. Then, they are described with the mixture Gaussian model and hidden Markov model (HMM), which can fit the dependency of wavelet coefficients between scales. Finally, the novel algorithm developed by the authors is compared with other wavelet-based denoising methods.Keywords：medical images;wavelet transform;hidden Markov model;denoising- 43
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Published：2020-08-12 -
Research on image enhancing for aerial photographs
Abstract：One of the necessary detecting measures in military use is aerial photoreconnaissance. Some upper process is needed for getting accurate information. The digital image processing technique becomes very important when further information can be obtained by the optically enlarging method.The algorithms of enhancement and edge extraction are both common methods.Normally,the system consists of sampling hardware and processing software. A practicable model of the digital image processing system is given and some corresponding algorithms are discussed in this paper.Keywords：aerial photography;digital image processing;image interpretation- 59
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Published：2020-08-12 -
Micro-move devices for supporting and adjusting large membrane mirrors
Abstract：Along with the development of space optics, the lightweighting of an optical system becomes more and more important. Membrane with active rigid support(MARTS) was first made at the University of Arizona. The mirror features lightweight and fine surface accuracy, and its surface can be adjusted by many actuators. The thickness of the membrane mirror is 2.1mm, diameter, 530mm, and mass, 1.25kg. The actuator designed on the principle of piezoelectricity has the micro-moving of 20nm. During the trial manufacture, the author made an actuator by the method of mechanism. Its principle of micro-moving is based on leverage and changing of height of arc in the spherical surface. It can realize 20nm micro-moving, too. This device is characterized by simple structure, high sensitivity and easy manufacturing.Keywords：reflection mirrors;lightweighting;micro-mechanism- 58
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Published：2020-08-12 -
Thermal analysis for a space optical remote sensor
Abstract：The thermal-controlling of a space optical remote sensor (SORS) is aimed at maintaining work temperature requirements to obtain images with high quality and resolution. A thermal analysis model of the optical remote sensor is built according to its structure characteristics and its thermal optics performance. The thermal performance of SORS is simulated by means of softwares Nevada and MSC/Patran. The analyzed results are also presented.Keywords：optical remote sensors;thermal controlling systems;temperature fields;thermal flux- 59
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Published：2020-08-12 -
Finite element analysis of the parallel girder load sensor
Abstract：The elastomer of a parallel girder load sensor affects the measuring precision directly. According to the structure and feature of the elastomer of a parallel girder load sensor, the rational finite element model of the elastomer was built, and in the course of exploiting Auto CAD of the sensor, a method of the automatic generation of the finite element mesh was founded. Dealing with three instances of line intersecting, the relationship between the out-stain and the dimension of the structure was also founded. Finally, by means of ViziCAD , the stress and strain of the finite element were analyzed.Compared the calculated value with the measured one of the output sensitivity,it is proved that they are nearly identical.Therefore, the finite element method can improve the precision and efficiency of the manufacture.Keywords：sensors;elastomers;finite element;ViziCAD- 55
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Published：2020-08-12 -
Applied investigation on the effects of bending stiffness of machine bed's simulating parts on its thermal geometrical precision
Abstract：In this paper, thermal analysis is narrated for two kinds of machine beds' simulating parts whose bending stiffnesses are not obviously equal under the condition of the thermal source similar to the environmental temperature or frictional heat. 3-D thermal conduction characteristics are discussed, and corresponding functional expression is also deduced. Moreover, temperature field distribution values are calculated by FEM program. The results show that they are near to the experimental values. Comparing machine beds’ simulating parts of small bending stiffness with those of large bending stiffness, the experimental results show that the former one's thermal geometrical precision is obviously better than the latter one′s. Therefore, in order to improve the structures of machine beds , for the first time ,this paper puts forward the idea that the gravity deformation of the simulating parts of machine beds can automatically compensate the thermal deformation caused by variable environmental temperature or frictional heat by means of properly decreasing the curving stiffness of the simulating parts and eliminating the bondage of other parts to the deformation of the machine beds’ simulating parts. This principle provides a new method of eliminating basically thermal deformation of large-scale and precision machine tools.Keywords：machine tools;machine beds’ simulating parts;bending stiffness;thermal geometrical precision;heat deformation- 62
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Published：2020-08-12 -
Research on the flexural hinge-based bender in a synchrotron radiation instrument
Abstract：A flexural hinge-based mechanical bender is a very promising dynamical one for synchrotron optics, which is driven by two PZT actuators. It is cheap and energy-tunable, and the precision of the mitrofigure produced by this elastic bender is high. This paper analyses and discusses its working principles classically and systematically, and derives the driving equation, i.e., the relationship between the mirror shape and driving forces. The finite element method is employed to verify the correctness of the equation based on the classical mechanical analysis. The article focuses on the effect on the mirror curvature radius produced by the derivation between the rotational axes and the neutral plane of the mirror, and the role of the flexure hinge in this elastic bender. It concludes that the bender driving equation can offer academic basis for designing the elastic bender.Keywords：synchrotron radiation;reflective mirrors;flexural hinges- 66
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Published：2020-08-12 -
Research on the application of subdivision modeling in CAD systems
Abstract：In existing CAD systems, classical NURBS patch method is used to build solids of irregular topology with some drawbacks: difficult patching-up and trimming, expensive computing and hard exact representing. However, in practical engineering application, there are many solids with complex shape, which require smooth ness and are difficult to be combined with basic elements. Subdivision modeling is a new and easily computing method, and can represent arbitrary topology, which has been widely researched in CAD. In this paper, the principles and methods of surface subdivision are described, and the kernel technologies for subdivision including mesh creation, boundary control, normal control, transformation from subdivision mesh to NURBS patch , Boolean calculation, etc., are studied. A scheme of using subdivision modeling in existing CAD system is presented, and a prototyping system of subdivision modeling is constructed. The experiment proves that by using this scheme, the modeling time is shortened and the efficiency is improved.Keywords：computer aided testing;subdivision surface;NURBS patches;boundary control- 53
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Published：2020-08-12
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