33results about How to "Avoid nonlinear errors" patented technology

The invention provides a displacement measuring device, a displacement measuring method and photoetching equipment. The displacement measuring device comprises a light source module, a diffraction element, a reading head assembly, an optical detection module and a signal analysis module; the reading head assembly is used for receiving two input light beams generated by the light source module andguiding the light beams to parallelly contact with the diffraction element and to be diffracted, and guiding and combining the diffracted input beams to form at least one output beam, wherein each output light beam comprises diffracted light signals which are emitted from the same light spot position of the diffraction element, are consistent in direction and respectively correspond to the two input light beams; and the displacement information of the diffraction element can be obtained according to the phase change information of interference signals of each output light beam. According to the displacement measurement device and the displacement measurement method, independent displacement measurement in different directions can be realized, wide-angle adaptive displacement measurement can be realized, and nonlinear errors can be reduced. The photoetching equipment comprises the displacement measuring device.

The invention relates to a device and a method for calibrating a flow-dividing vacuum leaking hole, in particular to the device and the method for calibrating the vacuum leaking hole, the leakage value of which is less than 1*10-8 Pa.m3 / s by adopting flow-dividing technology, and belongs to the field of measuring technology. The device consists of the calibrated leaking hole, a valve, an ionization gauge, a small hole, a flow-dividing chamber, a non-evaporable getter pump, an ultrahigh vacuum calibrating chamber, a metering hole, a very high vacuum pumping chamber, an oil-free bi-turbo molecular pump air exhauster set, a quadrupole mass spectrometer, a flow meter, a super-high vacuum calibrating chamber, the metering hole, a super-high vacuum pumping chamber and a common molecular pump air exhauster set. The method adopts a fixed flow method gas micro-flow meter to provide a known gas flow rate, so the measuring range of the flow rate is wide and uncertainty of the measurement is low;and by adopting a flow-dividing method to calibrate the vacuum leaking hole, the method of the invention completely avoids a nonlinear error of the quadrupole mass spectrometer and can precisely calibrate the vacuum leaking hole the leakage value of which is less than 1*10-8 Pa.m3 / s.

The invention relates to a five-axis numerical control interpolation method based on smooth compression of tool vectors. The five-axis numerical control interpolation method comprises the following steps: judging whether any two adjacent tool vectors meet the conditions of continuous processing according to a read numerical control processing program; if the conditions of continuous processing are met, carrying out compression interpolation of the tool vectors and interpolation of tool nose position; transforming a tool path to transform the tool nose position and tool vector values under a workpiece coordinate system to each axis coordinate under a machine tool coordinate system by utilizing points obtained after compression interpolation of the tool vectors and interpolation of the tool nose position; and fitting two adjacent points after transformation to generate a smooth curve by utilizing a quintic polynomial curve with continuous second derivative. With the adoption of the five-axis numerical control interpolation method, second order continuity of each component of the tool vectors can be ensured, large change of the tool vectors is avoided, nonlinear error generated by dynamic change of a rotation axis in a linear interpolation method is avoided, and the processing precision is improved.

The invention belongs to the technical field of precision displacement measurement, and discloses a displacement sensor and detection method of a suspension stylus based on differential polarization interference. The needle mechanism and the suspension stylus mechanism are connected to the voice coil motor; the voice coil motor includes a movably connected voice coil motor stator and a voice coil motor mover, and the voice coil motor mover is used to drive the suspension stylus mechanism to move vertically; The suspension stylus mechanism includes a suspension bearing connected to the voice coil motor mover and a stylus shaft movably connected to the suspension bearing; the differential polarization interferometer is used to measure the displacement of the stylus shaft relative to the suspension bearing to obtain the primary displacement; through Measure the displacement of the voice coil motor mover relative to the voice coil motor stator to obtain the secondary displacement, and combine the primary displacement and secondary displacement to obtain the measurement result of the surface to be measured. The invention improves the stability and reliability, and expands the measurement range.

The invention discloses a PVC (polyvinyl chloride) calender roller deflection signal processing device which comprises an X displacement signal acquisition circuit, a Y displacement signal acquisition circuit, a displacement signal processing circuit and a time delay circuit. Transverse and longitudinal displacement signals of PVC calender rollers can be acquired by laser sensors X1 and Y1 in the X displacement signal acquisition circuit and the Y displacement signal acquisition circuit, amplitude can be adjusted by a high-voltage step-down circuit and a low-voltage compensation circuit, then the transverse and longitudinal displacement signals can be filtered by an LC circuit, and voltages of the transverse and longitudinal displacement signals can be stabilized by a voltage stabilizer tube to be in the ranges of +5 V and +10 V. The PVC calender roller deflection signal processing device has the advantages that the shortcoming of nonlinear errors due to external disturbance can be overcome, the measurement accuracy can be improved, reliable on or off of MOS (metal oxide semiconductor) tubes T1-T4 can be guaranteed by the amplitude, and the accuracy of control signals can be improved; only simple logic judgment is carried out on the availability of transverse and longitudinal displacement deviation signals by a NAND gate circuit with the MOS tubes T1-T4 in the displacement signal processing circuit, the time is delayed by 5 S, determined high or low level can be outputted to a controller, accordingly, the PVC calender roller deflection signal processing device is fast in response and high in efficiency, deflection can be timely discovered and controlled, calendering effects can be guaranteed, and the work efficiency can be improved.

The invention relates to a neural network-based piezoelectric ceramic driver output control method, belonging to the field of wind tunnel model test vibration suppression, and relates to a neural network-based piezoelectric ceramic driver output control method suitable for wind tunnel active vibration suppression struts. The method first installs the piezoelectric ceramic driver data acquisition hardware system, collects the experimental data of the input voltage and output force of the piezoelectric ceramic driver, establishes the neural network model of the piezoelectric ceramic driver, uses the experimental data as the input and output of the neural network model, and selects Appropriate initial parameters are used to train the neural network model of the system, and finally the trained neural network model is called for application in the project. Compared with the traditional linear control method, this method avoids the nonlinear error on the control model, and makes the control result more accurate and with higher precision. In addition, this method is highly adaptable and can be applied to all systems containing piezoelectric ceramic actuators.

The invention relates to a main board for a thermometer and a thermocouple precision correcting method; the main board comprises a main control circuit consisting of a microprocessor, a dial-up input circuit, an interface circuit with at least two slots and a thermocouple sampling circuit; the invention controls the line structure of the sampling circuit with an A / D conversion circuit, reduces the line interference between digital and analog circuits, adds a zero calibration compensation circuit on the front end of the A / D conversion circuit and improves the accuracy of temperature measurement; the invention has the benefits that a bus-type interface circuit is adopted, and a plurality of interface circuit sockets are arranged to realize the extendibility of functions; the A / D conversion circuit is connected with the control end of the analog circuit, thereby reducing the connecting lines between the digital and the analog circuits, reducing the interference of the analog circuit to the digital circuit, and improving the work reliability; and the invention adds the zero calibration compensation circuit, so that when a zero point tends to be negative, the adjustment is very convenient, thereby preventing nonlinear zero-crossing error, and improving the accuracy of temperature measurement.

The invention provides a five-axis numerical control machining instruction point interpolation method based on tool attitude control, and relates to the field of numerical control machining. Including: obtaining tool tip position set P and tool axis vector set Q; obtaining parameter spline curve P(u); establishing local rotating coordinate system Q 0 ‑N‑V; get the tool axis vector curve Q(u); determine the included angle ψ k The parameter value u corresponding to the included angle k ; Determine parameter value u k The first and second order derivatives at the corresponding points; construct the curve ψ(u) that satisfies the second order continuity and determine the corresponding parameter values ​​of the kth interpolation cycle interpolation point; obtain the interpolation point and the corresponding tool axis vector of the next interpolation cycle . The present invention provides a five-axis numerical control machining command point interpolation method based on tool attitude control, which avoids the nonlinear error caused by the change of the rotation axis in the linear interpolation method, improves the machining accuracy, and avoids the distortion of the rotation axis of the machine tool. Great changes to improve the smoothness of the machined surface.

The invention discloses a method for measuring the frequency response of a photoelectric detector based on dual-tone modulation. Two channels with different frequencies ω 1 , ω 2 The microwave signal is modulated on the same optical carrier to generate an optical double-sideband signal of suppressed carrier; use the photodetector to be tested to convert the optical double-band signal of suppressed carrier into an electrical signal, and extract the up-converted and down-converted frequency Signal components, and calculate the amplitude-phase response of the photodetector to be tested accordingly. The invention also discloses a photodetector frequency response measuring device based on dual-tone modulation. Compared with the prior art, the invention can effectively reduce the measurement error introduced in the measurement process, improve the measurement accuracy and improve the dynamic range.

The invention discloses a PGC-DCDM demodulation method insensitive to phase delay and modulation depth. The sinusoidal phase modulation digital interference signal is multiplied with the first-order and second-order reference signals respectively and low-pass filtered to obtain a pair of quadrature signals about the phase to be measured; the quadrature signals are passed through the operation of differential cross division and multiplication The absolute value of the phase derivative to be measured is obtained by taking the absolute value and the square root operation, and the sign of the phase derivative to be measured is obtained according to the result of differential cross multiplication and division, and the derivative of the phase to be measured is obtained by combining the two. High-pass filtering operation to obtain the phase to be measured. The method of the invention solves the influence of the error factors introduced by the phase delay and modulation depth in the PGC demodulation on the demodulation result, effectively improves the phase demodulation accuracy, and can be widely used in fields such as interference optical fiber sensors, sinusoidal phase modulation interferometers, etc. .

The invention provides a polarization and birefringence measuring system in which measuring accuracy of polarization and stress birefringence is increased by using a multi-wave plate combination. The measuring system comprises a light source module, a light signal modulation module and a data collecting and processing module, wherein the light source module comprises a light source, a collimation and expansion system and a polarizer; the light signal modulation module comprises a multilevel phase difference coaxial wave plate, an analyzer, a stepping motor driving device and a stepping motor; and the data collecting and processing module comprises an image capture card, an luminous intensity detector and a computer. According to the polarization and birefringence measuring system, influences of changes of environments and measurement conditions such as air movement, temperature variation and uncertain vibration modes are effectively avoided; more than one independent phase modulation element is used for suppressing noises and averaging main error sources; and three wave plates are used for measuring the polarization and the birefringence, so that non-linear errors caused by non-linear influence of the system are effectively avoided, and the measuring accuracy is greatly improved.

The invention belongs to the technical field of antennas, and relates to a liquid metal reconfigurable array antenna based on a two-dimensional stretchable flexible cavity and a reconfiguration method thereof. The invention utilizes the fluidity of the liquid metal to construct a frequency reconfigurable microstrip antenna, the liquid metal is filled in the sealed flexible medium cavity, the flexible medium cavity can achieve 400% stretching and elongation, and the liquid metal radiator can be changed by stretching the flexible medium cavity The size can realize the continuous adjustment of the working frequency within 5~18GHz. Compared with the reconfigurable antenna using radio frequency devices, the antenna of the present invention can realize continuous tuning in a large frequency range. The elongation of the radiator is realized by automatic stretching equipment, which is more stable and practical than the injection-type reconfigurable liquid metal antenna.