位移传感器仿真器设计

针对目前机载系统地面试验的要求,设计了一种简单、驱动能力强、通用性好的位移传感器仿真电路。运用模拟乘法器AD633完成基准载波信号幅度的调制,简化了硬件电路的复杂度;利用运算放大器的非线性反馈以及三极管的电流放大特性,大大提高了电路的带负载能力;使用基准电压和以及调节接口的设置提高了仿真电路的通用性。在某飞机飞行控制系统地面试验中的应用表明,该位移传感器仿真电路能够实现角位移传感器及线位移传感器信号的仿真,运行稳定、波形良好,有一定的推广意义。     

微小位移光纤传感器谐波分析解调法研究

本文从理论上阐述了微小位移光纤传感器的一种分频比较法解调方案,并利用全光纤干涉光路进行了实验,结果表明采用这种解调方法可提高光纤传感器的测试精度、稳定性和动态范围。     

多信息输出位移传感器

本文提出一种用于空间自由曲面测量的多信息输出位移传感器.该传感器结构简单,传感器的输出量与被测量成线性关系,不但能给出位移信息、倾斜角度,还能给出测量光的强弱信息.     

反射式光纤位移传感器应用设计实验

基于光的反射原理并结合光纤传感器的特点,设计了反射式光纤位移传感器应用设计性实验.利用反射式光纤传感器测量微小位移的原理,通过测量输出电压与位移的关系确定工作点,测得表面柤糙程度不同的真假钞的输出信号,从而实现对纸币的真假识别.     

多路CCD位移传感器用于路面纵断面检测研究

本文提出了一种运用多路电荷耦合器件(CCD)位移传感器快速检测路面纵断面的测量系统,介绍了测量原理,给出了数据处理方法和实验结果.此系统设计时速最高为60km/h,路面高度分辨率为0.5mm,检测范围为±120mm.实验证明,此系统用于路面纵断面快速检测是可行的.     

用光栅式位移传感器测金属丝的杨氏模量

本文介绍了用光栅式位移传感器测量金属丝微小伸长量的实验方法。     

一种高精度光学位移传感器的设计分析

利用晶体双折射和由散射偏振引起的光学干涉技术,设计出一种高精度光学位移传感器.该传感器采用同轴光学系统,测量精度约为4 μm,测量范围不小于28 mm,且测量时不需要使用相干光源,故结构紧凑、性能稳定.     

激光位移传感器的光学系统设计

针对目前国内自主研制的激光位移传感器精度低,测量范围小等问题,提出了一种采用光学设计软件预先仿真整个激光位移传感器光学系统的方法。在分析系统各部分的光学特性的基础上,结合具体要求设计了一个激光位移传感器的光学系统,其工作范围为（50±10）mm。采用系统分割的方法,将整个光学系统分为两部分进行设计,第一部分是激光束的整形透镜,要求在有效的工作范围内得到小而均匀的出射光斑,设计结果表明,在测量范围内,光斑大小能够控制在10-1mm量级;另一部分是被测面散射光接收的成像物镜,该系统的特点是物面和像面相对于光轴都有一定的角度,实验结果表明其成像满足Scbeimpflug条件。     

利用电涡流传感器测量位移

本简单介绍了电涡流传感器的原理,给出了利用电涡流传感器测量位移的方法。     

油-气-水三相流超声传感器持气率测量

为探索油-气-水三相流持气率测量难题,该文开展了脉冲透射式超声传感器持气率测量动态实验研究。首先,利用超声传感器与光纤传感器组合,测取了油-气-水三相流中段塞流、混状流、泡状流的响应信号;其次,提取了超声脉冲信号的最大值序列来反映不同流型时超声传感器响应特性,同时,借助双头光纤传感器与相关测速法,计算得到了流体中气泡弦长序列;最后,结合流型与泡径信息,利用超声传感器测量了不同流型下持气率,并分析了不同流型持气率预测的误差来源,为其他油-气-水三相流持气率测量传感器设计提供了借鉴。     

基于广义合成阻抗超声传感器电端匹配的研究

超声波测距具有非接触、高准确度、价格低和使用方便等优点,被广泛应用于工业生产、医学检查、日常生活,如无人驾驶汽车、机器人、液位计等。在这些应用中,超声波传感器是应用中的最关键部件之一。因此,本文在分析了超声波传感器在谐振频率点等效电路的基础上,分别采用无源电感和有源电感对超声换能器的发射探头和接收探头进行电端匹配,提高了收发探头的效率。实验表明,匹配方法是有效的。     

A nonrational B-spline profiled horn with high displacement amplification for ultrasonic welding

A new horn with high displacement amplification for ultrasonic welding is developed. The profile of the horn is a nonrational B-spline curve with an open uniform knot vector. The ultrasonic actuation of the horn exploits the first longitudinal displacement mode of the horn. The horn is designed by an optimization scheme and finite element analyses. Performances of the proposed horn have been evaluated by experiments. The displacement amplification of the proposed horn is 41.4% and 8.6% higher than that of the traditional catenoidal horn and a Bézier-profile horn, respectively, with the same length and end surface diameters. The developed horn has a lower displacement amplification than the nonuniform rational B-spline profiled horn but a much smoother stress distribution. The developed horn, the catenoidal horn, and the Bézier horn are fabricated and used for ultrasonic welding of lap-shear specimens. The bonding strength of the joints welded by the open uniform nonrational B-spline (OUNBS) horn is the highest among the three horns for the various welding parameters considered. The locations of the failure mode and the distribution of the voids of the specimens are investigated to explain the reason of the high bonding strength achieved by the OUNBS horn.     

Quadrature demodulation technique for self-mixing interferometry displacement sensor

A new, to the best of our knowledge, signal processing method based on quadrature demodulation technique is presented for laser diode self-mixing interferometry(LDSMI) displacement sensor. Phase modulation of the laser beam is obtained by an electro-optic modulator (EOM) in the external cavity. Detection of the target's displacement can be easily achieved by sampling the interference signal at those times which satisfied certain conditions. The major advantage of the technique is that it does not involve any complicated calculation and insensitive to the sampling error. Experimental results show that the proposed method can effectively improve the displacement measurement resolution of the laser diode self-mixing displacement sensor to a few nanometers.     

Design of an ultrasonic sensor for measuring distance and detecting obstacles

This paper introduces a novel method for designing the transducer of a highly directional ultrasonic range sensor for detecting obstacles in mobile robot applications. The transducer consists of wave generation, amplification, and radiation sections, and a countermass. The operating principle of this design is based on the parametric array method where the frequency difference between two ultrasonic waves is used to generate a highly directional low-frequency wave with a small aperture. The aim of this study was to design an optimal transducer to generate the two simultaneous longitudinal modes efficiently. We first derived an appropriate mathematical model by combining the continuum model of a bar and countermass with the compatibility condition between a piezoelectric actuator and a linear horn. Then we determined the optimal length of the aluminum horn and the piezoelectric actuator using a finite element method. The proposed sensor exhibited a half-power bandwidth of less than ±1.3° at 44.8 kHz, a much higher directivity than existing conventional ultrasonic range sensors.     

Fabry-Perot interference-based fiber-optic sensor for small displacement measurement

A simple fiber-optic sensor based on Fabry-Perot interference for small displacement measurement is investigated both theoretically and experimentally. A broadband light source is coupled into a Fabry-Perot cavity formed by the surfaces of a sensing fiber end and the measured object. The interference signals from the cavity are reflected back into the same fiber. A small displacement via changes in cavity length can be obtained by measuring the wavenumber spacing of the interference fringes. The experimental data meet with the theoretical values very well. Given the light source bandwidth of 40 nm and the initial distance of 30 μm, the proposed displacement sensing system could achieve high resolution measurement of 16 nm.     

Design and operation of a double-fiber displacement sensor

Design and operation of a double-fiber sensor for displacement measurements are reported in this study. In this arrangement, one fiber transmits the laser light to the target and the second one receives the light reflected off the target and transmits to a photodetector. Utilizing inexpensive plastic optical fibers offers advantages such as higher reflexability and more robustness at a reasonable cost, which are required for some applications. The novelties of the reported design are compactness of the fiber probe, flexibility, long dynamic range (22 mm), and it is possible to use the source and the detector at the same side. The displacement of the target causes the intensity modulation and such a power variation is the base of sensor operation. Measurements for the metallic and non-metallic surfaces are performed and the results for aluminum, copper, and bronze sheets are presented here. Our results indicate that the sensitivity is highest for the plane mirror (288.8 mV/mm), high for the shiny metallic surfaces (230.6 mV/mm), but it can be used for other surfaces with a reasonable sensitivity. Important parameters of the sensor such as reproducibility (1.0%) and hysteresis effect (1.8%) are also investigated for this device. The theoretical formulation of the sensor operation is also developed and the computed results are compared with the experimental ones. The obtained experimental respond curve agrees well with the theoretical one, which verifies the successful operation of the proposed sensor system for precise displacement measurements.     

Quasi-distributed displacement sensor for structural monitoring using a commercial OTDR

A quasi-distributed displacement sensor for structural monitoring using an optical time domain reflectometer is demonstrated. Four displacement sensing heads are placed along a standard single mode optical fibre in several locations with different intervals. Their configurations introduce power loss through the decrease of their fibre loop radius when displacement is applied. The decrease of the light intensity with displacement variation is reported. Losses of 9 dB for a 120 mm displacement with a sensitivity of 0.027 dB/mm are reported. The quasi-distributed configuration is able to address sensors with 1 m distance resolution between them.     

A new laser displacement sensor based on triangulation for gauge real-time measurement

A new laser displacement sensor has been designed, constructed, and used in a train running at a speed of 64 km/h. The laser displacement sensor is insensitive to ambient light and to temperature. The parameters of the laser displacement sensor are as follows: the measurement range is 20 mm, and the laser displacement sensor resolution is 0.3 mm. All the results show that this new displacement sensor meets the requirement for real-time gauge measurement.     

Design of a Bézier-profile horn for high displacement amplification

A new horn for high displacement amplification is developed. The profile of the horn is a cubic Bézier curve. The ultrasonic actuation of the horn exploits the first longitudinal displacement mode of the horn. A design method of the horn using an optimization scheme and finite element analyses is developed. Prototypes of the horns are manufactured by a numerical control machining process. Performances of the proposed horn have been evaluated by experiments. Experimental results of the harmonic response of the fabricated horn confirm the effectiveness of the design method. The displacement amplification of the proposed horn is 71% higher than that of the traditional catenoidal horn with the same length and end surface diameters.