航空矢量发动机试车台推力校准技术综述

简述了航空矢量发动机试车台推力校准的必要性,介绍了现有涡扇发动机轴向试车台推力测量系统的校准方法,结合矢量推力试车台的结构特点,对矢量推力试车台校准现状、校准步骤进行了分析说明,给出了矢量推力试车台现场校准程序,最后对航空矢量发动机试车台推力校准技术研究进行了展望。     

一种新型的推力标定装置

推力校准在推力测量中占有举足轻重的地位,其校准精度直接影响测量结果。传统的校准方式精度差,效率低,已经无法满足当前的测量要求。本文提出了一种新型的在线推力校准系统,通过汽缸配合伺服电机产生稳定拉力,由压力控制系统、拉力活塞系统以及标准力传感系统形成闭环PID控制系统,实现拉力的精确控制,数据采集系统采集被校力值在上位机完成最终计算。     

高g值加速计和压电式力传感器的动态校准

本提出一种高g值加速度计的动态校准方法和装置,其最大加速度峰值超过100000g。这套装置还可以对压电式力传感器进行动态校准。中给出两个加速度计加速度峰值的二十余次实验结果,以及加速度计与力传感器的冲击响应实验曲线。同时,还求出它们的动态数学模型（包括差分模型、传递函数、频率特性）和动态性能指标。此外,还讨论了本的4个创新点。     

压电式力传感器连续加载的校准方法

针对压电式力传感器连续加载的校准方法进行初步探索。使用高精度应变式力传感器作为标准力传感器,在叠加式力标准装置上对压电式力传感器施加类似三角波式的连续载荷,利用数据采集系统采集标准力传感器和被校压电式力传感器的输出,记录整个加载过程,对输出曲线进行分析处理。提出了在连续加载曲线上选择校准点的方法,通过实验数据验证该校准方法的可行性,并对影响校准结果的各种因素进行了初步的分析。     

力传感器动态标定及其精度分析研究

对一种压电晶体力传感器动态标定系统进行了研究。首先介绍了这种动态力传感器标定系统的原理和构成;然后用区间算法分析了标定系统的精度,推导出了标定精度的具体表达式;最后对标定系统进行了大量的实验研究,比较了对标准质量块进行有悬挂和无悬挂安装两种实验方案的效果,研究了系统附加质量随频率变化的特性以及其他安装过程对标定结果的影响。研究表明:有悬挂安装法的一致性较差,对实验结果影响较大,无悬挂安装法的一致性较好;在中低频段,系统的附加质量变化幅度很小,力传感器的灵敏度也较为稳定,在高频段,系统的附加质量随标定频率的增加有显著增加,力传感器的灵敏度也有一定增大。这表明,在较高频带上进行实验时,力传感器的灵敏度有必要进行适当修正。     

压电式动态力传感器校准方法的研究

针对智能制造行业里压电式传感器的动态性能校准问题,介绍了针对传感器动态力参数的相关方法和脉冲力法校准装置,在装置上完成了试验验证和分析。介绍了两种常规的动态力校准方法,针对不同的校准方法建立了运动方程,做出了差异性分析。然后介绍了一种基于绝对法测量的压电式传感器脉冲力法校准装置,装置的结构包括基于刚体碰撞的脉冲力发生装置和基于外差式迈克尔逊干涉仪的测量系统,说明了工作原理和解算方法。最后利用建立的校准装置对典型压电式传感器进行动态力校准,进行结果分析和可靠性验证。     

测力刀柄系统标定技术研究

测力刀柄系统可实时监测切削过程的轴向力和扭矩的变化,为测试自主设计的测力刀柄系统的使用性能,设计并研制了一套标定辅助工装,搭建了标定实验平台,完成了静、动态标定实验。采用逐级加、卸载法,确定了测力刀柄系统的线性度、重复性和滞后性等静态特性指标;通过脉冲激励法获得了测力刀柄系统的固有频率、阻尼比和最大工作频率等动态特性指标。最后,针对测力刀柄系统进行了钻、铣削对比切削实验,结果表明,该系统与Kistler测力仪相比,在轴向和扭矩方向上的测量偏差均小于2%,能够准确反映动态切削过程中轴向力和扭矩的变化。     

基于微小形变测量的旋翼天平高精度测力校准系统

旋翼天平原位校准中,校准力精确加载是提高校准精度的重要因素。校准装置结构形变会给校准力加载造成误差,影响校准精度。针对这一问题,设计了旋翼天平测力校准系统。该系统采用激光三角法实现微小位移测量,通过测量立方靶块空间位置变化,计算力加载点位移;建立数学模型,分析结构形变对校准力加载影响,测量校准力。经实验,该系统可以消除结构形变影响,准确测量校准力,提高校准力加载精度。     

Thrust force model for ultrasonic-assisted micro drilling of DD6 superalloy

As a typical refractory material, the DD6 nickel-based single-crystal superalloy has important applications in the aviation industry. Ultrasonic-assisted drilling is an advanced machining method that significantly improves machining of refractory materials. The drilling thrust force influences the hole surface quality, burr height, and bit wear. Therefore, it is necessary to predict the thrust force during ultrasonic-assisted drilling. However, there are few reports on the modeling of the thrust force in the ultrasonic-assisted drilling of micro-holes. A thrust force prediction model for ultrasonic-assisted micro-drilling is proposed in this study. Based on the basic cutting principle, the dynamic cutting speed, dynamic cutting thickness, and acoustic softening effect caused by ultrasonic vibrations are factored into this model. Through model calibration, the specific friction force and specific normal force coefficients were determined. The model was verified through ultrasonic-assisted drilling experiments conducted at different feed rates, spindle speeds, frequencies, and amplitudes. The maximum and minimum errors of the average thrust force were 10.5% and 2.3%, respectively. This model accurately predicts the thrust force based on the parameters used for ultrasonic-assisted micro-hole drilling and can assist in the analysis and modeling of DD6 superalloy processing.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00381-y     

压电加速度传感器Hn估计校准方法

针对压电加速度传感器灵敏度校准过程中噪声对校准结果的影响难以消除的问题,结合Hn估计方法,利用其多次求互相关函数并求平均值的特性对系统噪声进行抑制。用"半长法"进行互相关计算,对多组采样信号进行互相关计算后再用FFT法进行功率谱计算,可得到功率谱的无偏估计。实验结果证明,利用该方法可提高压电加速度传感器灵敏度校准结果的准确度。     

全机推力试车台推力测量和校准方法

以目前国内唯一可进行发机装机状态下推力测试的试验设备为研究对象,介绍了其全机推力试车台的台架总体结构及飞机装机推力测量方式,重点对推力测量系统及其校准方法进行了详细描述,分析了全机推力测量的影响因素、测量结果修正方法及目前校准方法存在的不足,提出了装机校准、左右平台联合校准、伺服加载校准和原位校准等多种改进措施,提高了全机推力测量系统的校准准确度以及发动机装机推力的测量准确度,对于其他同类设备的校准也具有重要的参考和借鉴价值。     

Radially composite piezoelectric ceramic tubular transducer in radial vibration

The radially composite piezoelectric tubular transducer is studied. It is composed of radially poled piezoelectric and a long metal tube. The electro-mechanical equivalent circuit of the radially poled piezoelectric and metal tube in radial vibration is obtained. Based on the force and velocity boundary conditions, the six-port electro-mechanical equivalent circuit for the composite tubular transducer is given and the resonance/anti-resonance frequency equations are obtained. The relationship between the resonance frequency and the dimensions is analyzed. Numerically simulated results obtained by the finite element method are compared with those from the analytical method. Composite piezoelectric tubular transducers are designed and manufactured. The resonance/anti-resonance frequencies are measured, and it is shown that the theoretical results are in good agreement with the simulated and experimental results. It is expected that radially composite piezoelectric tubular transducers can be used as high-power ultrasonic radiators in ultrasonic applications, such as ultrasonic liquid processing.     

压电式压力传感器动态特性补偿技术研究

针对近爆区冲击波压力测试中压电式压力传感器因动态特性不佳造成信号畸变之问题,通过激波管动态校准试验,分析传感器动态特性;对造成动态测试误差的主要因素,利用动态补偿技术设计数字补偿滤波器,对传感器爆炸信号进行补偿处理。结果表明,该方法能有效减小动态测试误差、提高近爆区冲击波压力测试精度。     

A self-running standing wave-type bidirectional slider for the ultrasonically levitated thin linear stage

A slider for a self-running standing wave-type, ultrasonically levitated, thin linear stage is discussed. The slider can be levitated and moved using acoustic radiation force and acoustic streaming. The slider has a simple configuration and consists of an aluminum vibrating plate and a piezoelectric zirconate titanate (PZT) element. The large asymmetric vibration distribution for the high thrust and levitation performance was obtained by adjusting the configuration determined by finite elemental analysis (FEA). As a preliminary step, the computed results of the sound pressure distribution in the 1-mm air gap by FEA was com pared with experimental results obtained using a fiber optic probe. The direction of the total driving force for the acoustic streaming in the small air gap was estimated by the sound pressure distribution calculated by FEA, and it was found that the direction of the acoustic streaming could be altered by controlling the vibration mode of the slider. The flexural standing wave could be generated along the vibrating plate near the frequencies predicted based on the FEA results. The slider could be levitated by the acoustic radiation force radiated from its own vibrating plate at several frequencies. The slider could be moved in the negative and positive directions at 68 kHz and 69 kHz, which correspond to the results computed by FEA, with the asymmetric vibration distribution of the slider's vibrating plate. Larger thrust could be obtained with the smaller levitation distance, and the maximum thrust was 19 mN.     

装甲车辆传动装置试验台无损连接制动系统研究

传动装置试验台无损连接制动系统是传动装置试验台大转矩原位校准系统的重要组成部分,可实现对装甲车辆大转矩传动轴的无损连接制动.为了在满足现场空间要求的前提下保证原位校准的准确性,本文设计了一套与现场大转矩动力输出装置相匹配的无损连接制动系统.该系统不仅适用于现场狭小空间,而且可根据传动装置试验台输出转矩的大小提供与之匹配...     

串联发射弹丸内弹道力学特性测试方法研究

针对小口径高射频串联发射弹丸的内弹道力学特性测试问题,提出了基于弹载存储测试技术的弹底压力、弹前压力同步测试方法。设计了模拟弹和小型聚偏二氟乙烯(polyvinylidene difluoride, PVDF)压电式力传感器,将力传感器作为底螺与头螺部件承受并测量弹底压力与弹前压力,在发射过载条件下进行了传感器力学分析并推导了受力与输出的关系方程;分析了传力块的质量、厚度,PVDF薄膜的厚度、面积对传感器动态特性和温升的影响;进行了力传感器灵敏度理论建模与分析并开展了标定试验。结果表明,PVDF薄膜预紧力越大,传感器灵敏度越小。开展了串联发射试验,测试结果和内弹道数值模拟计算结果吻合较好。     

MEMS矢量水听器声压通道封装技术研究

为了更全面地获取水下声场信息,微机电系统（Micro-Electro-Mechanical System,MEMS）矢量水听器常需集成声压敏感通道来提升单个换能器性能,MEMS矢量水听器的敏感芯片采用的是MEMS工艺制备完成,其封装必须与水隔离,传统的橡胶灌封方式会破坏MEMS敏感芯片的机电性能,故MEMS敏感芯片常采用油封的方式,如硅油/蓖麻油。相反,对于MEMS矢量水听器声压通道的封装技术却不尽相同。文章选择给定尺寸的沿径向极化的压电陶瓷圆环,针对低频5～2 000 Hz的探测频带需求,对比了两种不同封装形式,即聚氨酯密封和硅油作为耦合剂的聚氨酯密封,对声压通道接收灵敏度的影响规律。首先,建立了四种仿真模型,分析了不同形式下,接收灵敏度的变化规律。接着,设计了聚氨酯灌封和硅油耦合聚氨酯密封两种封装结构,并制备了实物。最后在驻波管中对两种封装形式的压电陶瓷圆环进行了接收灵敏度标定。结果显示,聚氨酯灌封和硅油耦合聚氨酯密封对声压通道的接收灵敏度特性影响不大,实操过程中要注意两种方式的工艺复杂度区别。     

矢量水听器性能参数测试及分析

随着声呐探测系统性能和稳定性的不断提高,矢量水听器因能同时共点测量声波的声压和振速信息,已开始应用于声呐探测系统。为保障海上实验,设计制作了胶囊形三维压电同振式矢量水听器。依据比较法测量原理,分别在驻波声管和消声水池中,对矢量水听器的x、y、z和p通道的低频段和高频段进行了灵敏度和指向性测试。测试结果表明,该型矢量水听器灵敏度较高、指向性较好,能够满足海上实验的需求。     

Minimizing Thrust Fluctuation in Moving-Magnet Permanent-Magnet Brushless Linear DC Motors

We present the results of our research on the factors that cause thrust fluctuation in moving-magnet-type permanent-magnet brushless DC linear motors (PMBLDCLM). We combined Fourier transforms and finite-element models to obtain the power spectra of three components of the detent force. We developed a method of optimizing magnet width to minimize the detent force on the basis of harmonic analysis. To verify this method, we designed several motor models with different magnet widths and analyzed them by finite-element methods. The calculations and experimental results prove that thrust fluctuation of the motor can be effectively reduced with our method     

Application of time-delay spectrometry for calibration of ultrasonic transducers

Time-delay spectrometry (TDS) can conveniently be used for calibration and performance evaluation of piezoelectric electroacoustic transducers. The main emphasis of the work reported here is an experimental evaluation of the TDS technique. The TDS concept is introduced through a theoretical analysis. The experimental evaluation is carried out using specially designed measurement methods and instrumentation which uses a spectrum analyzer as the central analog signal processing unit. The optimal performance of the TDS measurement systems is analyzed in terms of relevant instrumentation parameters. The advantages and disadvantages of TDS, including practical performance limitations, are discussed, along with the measurement uncertainties of the method. It is shown that TDS in the frequence range covering both underwater acoustics and medical ultrasonics applications offers a viable alternative to other calibration techniques, such as those based on a gated burst measurement system.