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Stealth performance evaluation of helicopter against airborne early warning radar considering trimming control

Chinese Journal of Aeronautics 2023年第11期36卷 204-220页

作者： Zhongyang FEI Xiangwen JIANG Qijun ZHAO Zhuangzhuang CUI Yan YANG National Key Laboratory of Rotorcraft Aeromechanics College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

Airborne pulse Doppler radar is a key threat to the military helicopter,and assessing the stealth performance of helicopter against airborne early warning radar is helpful to the helicopter’s stealth design and operational planning.In this paper,the Shooting and Bouncing Ray(SBR)and Uniform Theory of Diffraction(UTD)based high-frequency algorithms are used to calculate the Radar Cross Section(RCS)of helicopter,and the radar range equations are used to evaluate the stealth performance.In order to account for the effects of rotor flapping motions during actual flight,the aerodynamics model of whole helicopter is established and the attitudes and controls of helicopter at different flight states are trimmed and input into the RCS calculation module.The effects of helicopter flight speed,flying direction and operational environment on radar stealth performance are studied in focus.It is demonstrated by the results that the trimming control does have a great influence of more than 5 dB on the RCS of helicopter,and the introduction of the trim calculation brings the helicopter’s returns calculation closer to the reality.Variations in flight speed lead to the changes in the stealth performance of helicopter against Early Warning Aircraft(EWA),and the helicopter flight speed can be planned according to the operational requirements to minimize exposure distance or exposure time.Variations in flying direction mainly affect the detection properties of helicopter returns,and flying in the same direction with EWA usually gives the helicopter better low-observability than flying head-on.Variations in operational environment mainly affect the radar detection performance and the sensitivity of the detection performance to external factors;the same amount of change in some external factor causes a different amount of change in the helicopter’s detectability in different environments.

关键词： Helicopters trimming Airborne early warning radar Stealth performance High-frequency algorithm Radar range equation

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Precision Balance Method for Cupped Wave Gyro Based on Cup-bottom trimming

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Chinese Journal of Mechanical Engineering 2012年第1期25卷 63-70页

作者： TAO Yi XI Xiang XIAO Dingbang TAN Yingqi CUI Hongjuan WU Xuezhong College of Mecha tronics Engineering and Automation National University of Defense TechnologyChangsha 410073China Wuhan Ordnance N.C.O.Academy Wuhan 430075China Department of Mechatronics Engineering Zhuhai CollegeJilin UniversityZhuhai 519041China

The mechanical balance process is the key process to eliminate the quadrature error and improve the performance of the cupped wave gyro. The conventional mechanical balance method for cupped wave gyro based on cup-wall trimming requires high control accuracy of trimming quantity, which increases the production cost and decreases the fabrication efficiency in large extent. However, it is hard to reach the high balance accuracy with the natural frequency split of mHz grade by using the conventional method. In this paper, the lumped mass dynamic model of the cupped wave gyro is built by discretization method, and the effects of different position trimming on the natural frequency are analyzed. It is pointed out that trimming off a tiny quantity of material from cup-wall causes large variation of the natural frequency is the main reason for the low accuracy of the conventional mechanical balance method. Then, a precision balance method for cupped wave gyro based on cup-bottom trimming is presented and the entire procedures of this method are given. The static balance process and dynamic balance process of the precision balance method are simulated by the finite element software. The simulation result shows that the precision balance method based on cup-bottom trimming brings less additional natural frequency split in the static balance process, minimizes the natural frequency split to mHz grade and rectify the angle of mode offset to 0.1° grade in the dynamic balance process, furthermore, the method decreases the requirement for control accuracy of trimming quantity evidently. The research work provides references for structure optimization design and balance process plan of the cupped wave gyro.

关键词： cupped wave gyro precision balance trimming modal analysis natural frequency split

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A trimming technique for capacitive SAR ADC as sensor interface

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Journal of Semiconductors 2015年第12期36卷 128-134页

作者：刘珂杜占坤邵莉马骁 Institute of Microelectronics Chinese Academy of Sciences

This work presented a trimming technique and algorithm applied in a capacitive successive approximation register（SAR） analog to digital converter（ADC） for a sensor interface, which can be integrated with the preceding sensor and the following controlling circuit. Without spending a special calibration phase or adding complicated functions, this circuit keeps a 12-bit resolution by trimming the capacitor array. Its merits of low power and small area make it suitable to be embedded in a power and cost sensitive system such as a battery-supplied sensor network node. The prototype 12-bit ADC is implemented by 0.5 m 2P3M CMOS technology, with the wide supply range of 2–5 V, its power consumption is only 300 A at a sampling speed of 200 kHz.

关键词： SAR ADC trimming sensor CMOS

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A hybrid method for product low-end disruptive innovation

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Frontiers of Mechanical Engineering 2022年第3期17卷 159-176页

作者： Yu WANG Runhua TAN Qingjin PENG Jianguang SUN Haoyu LI Fei YU School of Mechanical Engineering Hebei University of TechnologyTianjin300401China National Engineering Research Center for Technological Innovation Method and Tool Hebei University of TechnologyTianjin300401China Department of Mechanical Engineering University of ManitobaWinnipegMBR3T 2N2Canada

Product innovation is often a process for improving existing products.Low-end disruptive innovation(LDI)enables a product to meet the most price-sensitive customers in the low-end market.The existing LDI methods are mainly based on unnecessary characteristics of disruptive innovations.Thus,they cannot easily identify and respond to the LDI design needs.This study proposes a hybrid method for the product LDI in two levels of the product design based on the summarized definition and essential characteristics of LDI.Feasible areas of the product LDI are determined using a hybrid relational function model to identify the maturity of dominant technologies.The technologies are identified through the technical search and evaluation of the feasible area for innovation to form an initial LDI scheme.Then,the product function is optimized using the trimming concept of theory of inventive problem solving based on the characteristics of LDI.The final LDI scheme is formed and evaluated based on the essential characteristics of the product LDI.The feasibility of the proposed method is verified in the design of a new dropping pill machine.

关键词： low-end disruptive innovation product design design improvement theory of inventive problem solving TRIZ trimming

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Laser trimming of the operating wavelength of silicon nitride racetrack resonators

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Photonics Research 2020年第5期8卷 677-683页

作者： GRETA DE PAOLI SENTA L.JANTZEN THALIA DOMINGUEZ BUCIO ILIAS SKANDALOS CHRISTOPHER HOLMES PETER G.R.SMITH MILAN M.MILOSEVIC FREDERIC Y.GARDES Department of Information Engineering Universitàdegli Studi di PadovaVia Giovanni Gradenigo 635131 PadovaItaly Optoelectronics Research Centre University of SouthamptonSouthampton S0171BJUK

We demonstrate the possibility of post-fabrication trimming of the response of nitrogen-rich silicon nitride racetrack resonators by using an ultraviolet laser.The results revealed the possibility to efficiently tune the operating wavelength of fabricated racetrack resonators to any point within the full free spectral range.This process is much faster than similar,previously presented methods(in the order of seconds,compared to hours).This technique can also be applied to accurately trim the optical performance of any other silicon photonic device based on nitrogen-rich silicon nitride.

关键词： trimming track faster

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Dynamic response analysis under atmospheric disturbances for helicopters based on elastic blades

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Chinese Journal of Aeronautics 2017年第2期30卷 628-637页

作者： Tong Liu Yuting Dai Guanxin Hong Linpeng Wang School of Aeronautic Science and Engineering Beihang University Beijing 100083 China

A flight dynamics model based on elastic blades for helicopters is developed.Modal shape analysis is used to describe the rotating elastic blades for the purpose of reducing the elastic degrees of freedom for blades.The analytical result is employed to predict the rotor forces and moments.The equilibrium equation of the flight dynamics model is then constructed for the elastic motion for blades and the rigid motion for other parts.The nonlinear equation is further simplified,and the gradient descent algorithm is adopted to implement the trim simulation.The trim analysis shows that the effect of blade elasticity on the accuracy of rotor forces and moments is apparent at high speed,and the proposed method presents good accuracy for trim performance.The timedomain response is realized by a combination of the Newmark method and the adaptive RungeKutta method.The helicopter control responses of collective pitch show that the response accuracy of the model at a yaw-and-pitch attitude is improved.Finally,the influence of blade elasticity on the helicopter dynamic response in low-altitude wind shear is investigated.An increase in blade elasticity reduces the oscillation amplitude of the yaw angle and the vertical speed by more than 70%.Compared with a rigid blade,an elastic blade reduces the vibration frequency of the angular velocity and results in a fast return of the helicopter to its stable flight.

关键词： Dynamic model Elastic Helicopter Time domain analysis trimming Wind shear

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New Hybrid AD Methodology for Minimizing the Total Amount of Information Content:A Case Study of Rehabilitation Robot Design

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Chinese Journal of Mechanical Engineering 2020年第6期33卷 177-186页

作者： Tao Yang Xueshan Gao Fuquan Dai School of Design Fujian University of TechnologyFuzhou350118China School of Mechatronical Engineering Beijing Institute of TechnologyBeijing100118China Department of Mechanical and Automotive Engineering Fujian University of TechnologyFuzhou350118China Fujian Haiyuan Composite Materials Technology Co. Ltd.FuzhouChina

Converting customer needs into specific forms and providing consumers with services are crucial in product design.Currently,conversion is no longer difficult due to the development of modern technology,and various measures can be applied for product realization,thus increasing the complexity of analysis and evaluation in the design process.The focus of the design process has thus shifted from problem solving to minimizing the total amount of information content.This paper presents a New Hybrid Axiomatic Design(AD)Methodology based on iteratively matching and merging design parameters that meet the independence axiom and attribute constraints by applying trimming technology,the ideal final results,and technology evolution theory.The proposed method minimizes the total amount of information content and improves the design quality.Finally,a case study of a rehabilitation robot design for hemiplegic patients is presented.The results indicate that the iterative matching and merging of related attributes can minimize the total amount of information content,reduce the cost,and improve design efficiency.Additionally,evolutionary technology prediction can ensure product novelty and improve market competitiveness.The methodology provides an excellent way to design a new(or improved)product.

关键词： Axiomatic design Amount of information content trimming Rehabilitation robot

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trimming在自行车锁创新设计中的应用研究

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北京印刷学院学报 2016年第4期24卷 59-62页

作者：刘富李艳张彦辉北京印刷学院数字化印刷装备北京市重点实验室北京102600

为了得到一种新型自行车锁,采用TRIZ理论进行自行车的一系列功能分析,了解自行车锁的有用功能,得出自行车各个主要组件的功能得分,再运用trimming得出其他组件执行阻止自行车锁转动功能的方案,最终设计出一种新型自行车脚蹬子锁。选取... 详细信息

为了得到一种新型自行车锁,采用TRIZ理论进行自行车的一系列功能分析,了解自行车锁的有用功能,得出自行车各个主要组件的功能得分,再运用trimming得出其他组件执行阻止自行车锁转动功能的方案,最终设计出一种新型自行车脚蹬子锁。选取一款普通自行车作为实验对象,通过测量现有自行车的脚蹬子来确定所设计的新型脚蹬子锁的结构,加工出模型装配在该自行车上。经过实践分析,证明该脚蹬子锁能实现锁车的功能。

关键词：自行车 trimming 脚蹬子锁创新设计

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基于TRIZ理论的trimming裁剪方法的产品优化设计

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起重运输机械 2014年第3期 15-17页

作者：梁长佳田红周高静轩安徽合力股份有限公司合肥230601

创新方法 TRIZ理论中的trimming裁剪方法是按照功能分析的结果,对技术系统中各组件进行价值分析,找出价值最低的组件,实施系统裁剪,以达到降低成本、提高技术系统理想度的目的。通过掌握trimming的几种裁剪方法,工程师可较容易地在产品... 详细信息

创新方法 TRIZ理论中的trimming裁剪方法是按照功能分析的结果,对技术系统中各组件进行价值分析,找出价值最低的组件,实施系统裁剪,以达到降低成本、提高技术系统理想度的目的。通过掌握trimming的几种裁剪方法,工程师可较容易地在产品优化设计上找到明确的方向。文中以实际测试中提高转速传感器支架的安置效率为例,介绍trimming对工程师在思路创新上的启发。

关键词：叉车 TRIZ trimming 价值分析优化设计

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A Histogram-Based Static-Error Correction Technique for Flash ADCs

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ZTE Communications 2011年第4期9卷 35-41页

作者： Armin Jalili J Jacob Wikner Sayed Masoud Sayedi Rasoul Dehghani Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156-83111 Iran Department of Electrical Engineering Linkping University SE-581 83 Linkping Sweden

High-speed, high-accuracy data converters are attractive for use in most RF applications. Such converters allow direct conversion to occur between the digital baseband and the antenna. However, high speed and high accuracy make the analog components in a converter more complex, and this complexity causes more power to be dissipated than if a traditional approach were taken. A static calibration technique for flash analog-to-digital converters （ADCs） is discussed in this paper. The calibration is based onhistogram test methods, and equivalent errors in the flash ADC comparators are estimated in the digital domain without any significant changes being made to the ADC comparators. In the trimming process, reference voltages are adjusted to compensate for static errors. Behavioral-level simulations of a moderate-resolution 8-bit flash ADC show that, for typical errors, ADC performance is considerably improved by the proposed technique. As a result of calibration, the differential no.nlinearities （DNLs） are reduced on average from 4 LSB to 0.5 LSB, and the integral nonlinearities （INLs） are reduced on average from 4.2 LSB to 0.35 LSB. Implementation issues for this proposed technique are discussed in our subsequent paper, “A Histogram-Based Static-Error Correction Technique for Flash ADCs： Implementation Aspects. ”

关键词： Calibration flash ADC offset trimming uniform distribution

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