【作者】 刘敏；

【导师】 崔俊宁；

【作者基本信息】 哈尔滨工业大学 ， 仪器科学与技术， 2019， 硕士

【摘要】 高精度电感位移传感器凭借其测量精度高、结构简单、线性度好等优势被广泛应用于精密零件尺寸与形位测量中。在以压缩机涡旋盘为代表的复杂沟槽、内腔等结构的精密测量中对电感位移传感器提出了双向测量与纳米分辨力要求。传统的旁向电感位移传感器测头测量精度已经可以达到纳米量级,但是大多数只能实现单向测量;在信号处理方面,开关式相敏检波方案中存在较大的高频噪声,数字相敏检波对控制时序要求严格,容易产生漂移;此外,环境温度变化使传感器测头产生温度漂移,是制约电感位移传感器精度提高的关键因素之一。本论文面向以涡旋盘为代表的复杂沟槽、内腔等结构的尺寸及形位精密测量的需求,提出了一种能兼顾纳米分辨力和一维双向测量的电感微位移传感器测头结构,设计并研制了高精度信号处理电路,设计了基于测头恒温控制的漂移抑制系统设计。论文主要工作如下:首先,提出了一种能兼顾双向测量与纳米分辨力的双向电感位移传感器测头结构。采用双片簧交叉柔性铰链作为传感器测头的弹性支撑元件,分析了铰链轴漂、迟滞等引起的测量误差。针对测头机械零件的加工误差、安装定位误差引起测量非线性问题,分析了加工误差和安装误差的非线性误差模型。针对环境温度波动对测头稳定性的影响,分析了测头机械结构热变形对测量结果的影响。其次,针对数字相敏检波对电路时序要求严格,容易产生非线性误差和漂移,常用的模拟相敏检波方法噪声较大等问题,设计了基于乘法器相敏检波的信号处理方案。采用电阻平衡臂电桥作为调制电路,减小了信号电路体积,提高了电路的抗干扰能力;通过乘法器相敏检波电路对调幅调制信号进行解调,有效地减小了开关信号引入的高频干扰,降低了对电路的时序要求,减小了信号处理电路的非线性;建立了信号处理电路的完整噪声模型,定量分析了电路参数对信号处理电路输出噪声的影响,根据噪声模型对电路主要参数进行了优化设计,减小了信号处理电路的噪声。针对电感位移传感器测头结构和信号处理电路存在的各种非线性误差,设计了补偿环节,减小了电感位移传感器测量结果的非线性。然后,针对传感器测头内部温度变化引起传感器输出信号漂移问题,设计了基于测头恒温控制的传感器漂移抑制系统。分析了传感器测头恒温控制系统的控制模型,通过系统辨识确定了其开环传递函数,根据辨识结果确定了PID控制器的主要参数。实验结果表明,测头恒温控制系统的温度稳定性优于0.1℃/1h,电感位移传感器输出信号的漂移由加入恒温控制系统前的80nm/30min提升到加入恒温控制系统后的40nm/1h。最后,搭建实验测试平台,对本论文研制的高精度双向电感位移传感器进行了实验测试。实验测试结果表明,传感器在±100μm量程内的测量分辨力为5nm,稳定性为40nm/1h,非线性为0.4%,测量重复性优于60nm,回程差小于50nm。本论文设计的双向电感位移传感器实现了双向测量与纳米分辨力。更多还原

【Abstract】 High precision inductive displacement sensor is widely used in the measurement of the size and surface topography of precision parts because of its advantages of high accuracy,simple structure and good linearity.Bidirectional measurement and nanoresolution are required for inductance displacement sensor in measuring the dimensions and surface topography of grooves and cavities of complex parts represented by scroll compressors.Traditional inductive displacement sensor probes can only realize one-way measurement,but can not take both nano-resolution and bidirectional measurement into account.The signal processing circuits of inductive sensor is very sensitive to noise,and there are large high-frequency noises in commonly used digital phase-sensitive detection and switched phase-sensitive detection schemes.The mechanical structure of sensor probes is sensitive to temperature changes.the change of ambient temperature will cause the thermal drift of sensor probe,but there are few studies on the drift suppression of sensor probe.In this paper,aiming at the requirement of measuring the surface size and shape of special parts such as scroll compressor,and the existing problems of inductance displacement sensor,a structure of inductance displacement sensor which can realize bidirectional measurement and effectively suppress temperature drift is proposed.The high precision signal processing scheme of inductance displacement sensor is designed,and the constant temperature control system of the probe is designed.The main contents of this paper are as follows:Firstly,a new type of bi-directional inductance displacement sensor probe structure is designed,which expands the measurement direction of inductance displacement sensor so that it can be used as bi-directional measurement.The cross flexible hinge of double leaf spring is used as the elastic support element of the sensor probe.The measurement errors caused by the drift and hysteresis of the hinge shaft are analyzed in detail.Aiming at the measurement non-linearity caused by the machining error and installation positioning error of the probe mechanical parts,the non-linearity error model of the processing error and installation error is analyzed.In view of the influence of ambient temperature fluctuation on the stability of the probe,the influence of thermal deformation of the mechanical structure of the probe on the measurement results is analyzed.Secondly,in view of the strict requirements of digital phase-sensitive detection on ADC sampling timing,the introduction of non-linear errors,and the low detection accuracy of commonly used analog phase-sensitive detection methods,this paper designs a signal processing scheme based on multiplier phase-sensitive detection.Using resistance balance arm bridge as modulation circuit reduces the volume of signal circuit and electromagnetic radiation,and improves the anti-interference ability of the circuit;demodulating the AM modulation signal by multiplier phase sensitive detection circuit effectively reduces the high frequency interference introduced by switching signal in the circuit,reduces the timing requirements of ADC sampling circuit,and reduces the nonlinearity of signal processing circuit.The complete noise model of signal processing circuit is established,the influence of circuit parameters on the total output noise of signal processing circuit is quantitatively analyzed,and the main parameters of the circuit are optimized according to the circuit noise model.According to the non-linear error model of machining error and installation error,the compensation link of sensing characteristic is designed,which reduces the measurement non-linearity caused by the machining and installation error of the probe’s mechanical structure.Then,a constant temperature control unit of sensor based on PID control is designed.The system model of constant temperature control system of inductive displacement sensor probe is analyzed.The open-loop transfer function of constant temperature control system is determined by system identification,and the main parameters of PID controller are determined according to system identification results.Under the set working temperature,the temperature control stability is better than 0.1℃/1h.The stability of inductive displacement sensor system is improved from 80nm/30 min before adding temperature control unit to 40nm/1h.Finally,an experimental platform is built to test the performance of the highprecision bi-directional inductance displacement sensor probe and signal processing board.The experimental results show that the measurement resolution of the two-way inductive displacement sensor system is 5nm,the stability is 40nm/1h,the system nonlinearity is 0.4%,and the measurement repeatability is 60 nm in the measurement range of ±100μm.The measurement system of bi-directional inductance displacement sensor designed in this paper has good performance.更多还原