Research On Error Separation And Suppression Method Of Magnetic Field Type Time Grating Displacement Sensor

Field type time-grating displacement sensor is a displacement sensor based on the space-time conversion of ideas a,with magnetic field as medium transformation space displacement is the amount of time,so as to realize the measurement of angular displacement or linear displacement.Field type time-grating displacement sensor as a precision displacement measurement sensor,the measurement accuracy is an important index of performance evaluation of the sensor,how to improve the measurement accuracy has been a focus of research of this type of sensor.Therefore,in this paper,the research on the error separation and the various error suppression methods of the magnetic field type time-grating displacement sensor is suitable for the displacement sensor.At home and abroad,the error analysis and suppression of displacement sensor has a certain research foundation,the error is mainly divided into three aspects: mechanical,electrical and installation.Mechanical error due to machining and processing parameters are not reasonable,can be divided into tooth shape,tooth pitch,pole number,number of rotor teeth;electrical error due to the signal processing circuit,the signal processing error can be divided into incentive and weak induction signal processing error;installation error due to the installation of the mechanical structure is not ideal,mainly focus on the sensing unit installation.The error suppression method is mainly divided into hardware processing method and software processing method.The hardware processing method to improve the precision of measurement by changing the parameters of mechanical or electrical sensor,such as grating precision reticle,rotary transformer optimization tooth shape,tooth pitch,the number of poles,stator and rotor tooth number ratio;software processing method is implemented to reduce the measurement error by software method,so as to improve the measurement accuracy,such as harmonic correction method and point by point correction chart etc..The hardware processing method is mainly restrain the measurement error from the sensing source,so when is priority method of the magnetic field grating displacement sensor improve the measurement accuracy,but need to make more accurate judgments the sources of measurement error;software processing method not only the error suppression effect,and has the advantages of simple operation and low cost.Because the two have their own advantages and disadvantages,we should consider and reasonably apply the two methods.The measurement error of field type time-grating displacement sensor includes 0,1,2,3 and higher harmonic components,the author believes that the strong regularity and the fixed error exists,most can be attributed to a link of sensors in the system,so this article as a starting point,combined with the research status of this topic for each other,research time-grating measurement error mainly from the following four aspects.(1)The excitation signal source error is separated.The amplitude and phase error of the excitation signal source directly affect the linearity of the phase change of the signal.For this reason,a high precision excitation signal source is designed based on FPGA.The experimental results show that the accuracy of the signal source is improved and the measurement error is reduced.(2)In this paper,the error caused by the measurement of the tooth unevenness isseparated from the theory,and the mathematical model is established.Then,by comparing the measurement performance of the sensors with different processing technology,the influence of the nonuniformity of the stator and rotor teeth on the measurement accuracy of the sensor is verified.(3)The error of square wave forming module is separated,and the improved weak signal processing method is applied.To solve the problem of the measurement error brought by absolute zero offset,the technology of differential technology is proposed,the differential comparison experiments show that this way inhibited the random errors in the measurement of the gate;(4)according to the experimental results and the theoretical data are different problems,namely solving module and error bring new error,time-grating module the error of system is analyzed,the overall suppression means is proposed,such as weak signal processing method research,calibration method,compensation algorithm,etc.The subject of this paper research the applicability of the variable reluctance magnetic field time-grating displacement sensor,also apply to other magnetic field,electric field and light field type time-grating.