42results about How to "Simple compensation process" patented technology

A sensing system including a sensor having an enclosure that defines a chamber, a fiber optic segment extending from outside the enclosure into the chamber, and a sequence of optical processing elements within the chamber. The elements include a fiber Bragg grating, a polarizer, a side hole fiber, and a mirror. A light source is arranged to direct light to the sensor(s). A spectral analyzer is arranged to detect light reflected back from the sensor(s). The fiber Bragg grating substantially reflects a first spectral envelope while transmitting the remainder of the optical spectrum to the polarizer and side hole fiber. The polarizer, side hole fiber, and mirror cooperate to return an optical signal within a second spectra! envelope. The characteristic wavelength of a peak in the first spectral envelope is highly sensitive to temperature and relatively weakly sensitive to pressure. The period of the optical signal within the second spectral envelope is highly sensitive to pressure and relatively weakly sensitive to temperature. The spectral analyzer measures these spectral components to simultaneously derive a measure of temperature and pressure that effectively compensates for temperature-pressure cross-sensitivity of the sensor(s).

An optical compensation method for a display device including a pixel is provided. The method includes: providing test data having a first grayscale value to the display device; measuring a luminance of the pixel which emits light based on the test data; and calculating a compensation grayscale value based on a second target luminance and the measured luminance of the pixel. The second target luminance is lower than a first target luminance which is set based on the first grayscale value.

The invention discloses a device and a method for compensating a composition error of a main shaft in real time. The device comprises a radial capacitance displacement sensor, an axial capacitance displacement sensor, a control computer, a two-degree of freedom sharp knife servo controller and a two-degree of freedom sharp knife servo unit, wherein the output end of the radial capacitance displacement sensor is connected with the first input end of the control computer; the output end of the axial capacitance displacement sensor is connected with the second input end of the control computer; the two-degree of freedom sharp knife servo controller is respectively connected with the control computer and the two-degree of freedom sharp knife servo unit; the two-degree of freedom sharp knife servo unit is connected with a processing cuter; the radial capacitance displacement sensor is arranged at one side of the processing cutter, and the axial line thereof is vertically intersected with the axial line of a work-piece; the axial capacitance displacement sensor is arranged on one end face of the work-piece, and the axial line thereof is vertical to the end face of the work-piece. The device and the method for compensating the composition error of the main shaft in real time can perform on-line and real-time measurement and compensation on the composition error simply, rapidly and comprehensively, and can be widely applied to the field of precision machine tool machining.

The invention discloses an error compensation method for a photoelectric encoder. Based on improved particle swarm optimization and a Fourier neural network principle, the method is used for improving the measurement accuracy of the photoelectric encoder, and is particularly suitable for an angle measuring system requiring low cost and high accuracy. According to the method, a compass error is modeled by a Fourier neural network, and the weight of the neural network is optimized by the improved particle swarm optimization, so that an accurate error model is obtained to compensate a measured value of the photoelectric encoder. The error model established by the method can realize accurate mapping of a sample space and has high nonlinear approximation capability; and by the method, local minimum is avoided, a defect that the neural network has ultralow convergence rate, oscillates and the like is overcome, measurement errors of the photoelectric encoder are effectively reduced, and the measurement accuracy of the photoelectric encoder is greatly improved.

The invention discloses a neural-network-based rapid compensation method for photoelectric encoder. The method can increase compensation precision and compensation speed, and can simplify compensation procedures and reduce requirements to a needed instrument. The method includes: first, randomly rotating the photoelectric encoder in a circle, and acquiring a training sample; then adopting a single input and single output three-layer feed-forward Fourier neural network to establish a photoelectric encoder error compensation model, and estimating the number of nodes in hidden layers based on the characteristics of an object function; at last based on the actual result, correcting the number of the nodes so as to prevent the inefficiency due to repeated and varied attempts in a trial-and-error method. According to the invention, directed to the problem of slow convergence of the iteration training method, the method, through mapping the errors to nodes in the hidden layers of orthogonal triangle function basis, rapidly solves a minimum norm solution from the hidden layers to a weight of an output layer, which substantially reduces the time required by solving the weight of the neural network and greatly reduces time complexity and space complexity in calculation.

The invention discloses a digital temperature compensation method of a crystal oscillator, wherein a closed-loop feedback compensation framework is adopted. According to the method, a binary coding B0i corresponding to a target frequency f0 is determined and stored in a microprocessor. When the temperature changes, the microprocessor conducts real-time measurement on the output frequency of a VCXO to generate a binary code B1i. Meanwhile, the microprocessor compares with the above binary code B1i with a binary code corresponding to the target frequency to obtain a binary code of the needed compensation information. Finally, the binary code of the needed compensation information is converted into a compensation voltage through a digital-to-analog converter to be input to a voltage-controlled adjusting end of the VCXO. Therefore, the target frequency is output, and the temperature compensation is achieved. Compared with a digital temperature compensation method of an existing crystal oscillator, the above digital temperature compensation method does not need any temperature sensor. Meanwhile, the frequency deviation related to the temperature in real time is directly converted into a binary code which is in one-to-one correspondence with the temperature. Moreover, the binary code is converted into a corresponding compensation voltage for temperature compensation. Therefore, the temperature hysteresis problem caused by the fact that the temperature change of a temperature sensor and the temperature change of a crystal resonator are not synchronous in an existing temperature compensation crystal oscillator (TCX0) is overcome.

The present invention relates to a device for compensating a radio frequency distortion caused by a sample/hold operation of a digital/analog converter in an orthogonal frequency division multiplexing (OFDM) transmission system, and a method thereof. In a digital transmission system, an edge frequency signal of a transmission signal band is distorted by a sample/hold operation of a digital/analog converter such that a signal attenuation is generated at a frequency domain by a sync function having a zero point at a sample frequency of a transmission signal. In the present invention, the signal distortion may be compensated by multiplying a coefficient of an inverse sync function by a signal weight value at the frequency domain, and it may be compensated by using a single multiplier and a lookup table storing the coefficient of the inverse sync function.

The invention discloses a stepping temperature compensation method of a crystal oscillator. The method adopts the closed-loop feedback compensation architecture, and comprises the following steps: firstly determining the binary coding B0i corresponding to a target frequency f0, and storing in a single chip microcomputer; when the temperature change is existent, sending a signal with a mode frequency of f(T) to an A/D converter to convert into the corresponding binary coding B1i, and inputting to the single chip microcomputer to compare with the binary coding B0i of the target frequency f0, setting the threshold range deltaB in the single chip microcomputer, comparing the B0i with the B1i, judging whether a comparison result B0i-B1i is in the threshold range; if the B0i-B1i is not in the threshold range, compensating by using the stepping binary coding B2i, and then sending into the single chip microcomputer to compare with the B0i after the compensation, cyclically compensating in this way until the comparison result B0i-B1i is in the threshold range, thereby finally realizing the temperature compensation. Compared with the existing temperature compensate crystal oscillator, the method disclosed by the invention is free from using a temperature sensor, a temperature hysteresis problem caused by asynchronous wafer temperature change of the temperature sensor and the crystal resonator in the existing TCXO is overcome.

The invention discloses an analog anti-vibration crystal oscillator compensation device and method. A voltage-controlled crystal oscillator, a power divider, a high-frequency frequency-voltage conversion circuit, a voltage comparison circuit, an adder and a filter are connected in sequence to form a closed-loop compensation framework, frequency is directly associated with compensation voltage through the high-frequency frequency-voltage conversion circuit, and real-time high-precision compensation is easier to achieve. An acceleration sensor is not needed, the frequency related to vibration inreal time is directly converted into the compensation voltage in one-to-one correspondence with the frequency for compensation, and the hysteresis problem caused by asynchronous acceleration when anacceleration sensor and a crystal resonator wafer are used in an existing anti-vibration crystal oscillator can be solved. The compensation process and the compensation structure are simple, integration and batch production are easy. The invention can be well suitable for crystal oscillators of various frequencies, and especially for high-frequency crystal oscillators poor in compensation effect..

The embodiment of the invention provides an encoder calibration system and a control method thereof, and relates to the field of encoder calibration. The invention aims to solve the problem that the precision of an existing encoder calibration system needs to be improved. According to the encoder calibration system, a motor is provided with an output shaft, an encoder to be calibrated and a standard encoder are both connected with the output shaft, the encoder to be calibrated is used for outputting a first rotating speed signal, the standard encoder is used for outputting a second rotating speed signal, and a controller is used for carrying out first-time precision compensation on the encoder to be calibrated according to the first rotating speed signal and the second rotating speed signal. The control method of the encoder calibration system is executed by the controller. The rotating speed can reflect the running state of the motor more directly, the encoder to be calibrated and thestandard encoder both output rotating speed signals, precision compensation is carried out through the rotating speed, the compensation precision is higher, meanwhile, the encoder to be calibrated and the standard encoder are connected through a shaft, the running variables of the motor are the same, and the calibration precision of the encoder to be calibrated is improved.

The present invention simplifies the processing for compensating an influence for a controlled quantity generated from shaping interference in motion control. A controller (10) as a model predictive control device computes an error between an actually measured value of a controlled quantity in a certain action cycle when shaping interfering is applied and a predictive value of the controlled quantity in the certain action cycle, i.e., the model predictive error, and corrects the predictive value in the action cycle after the certain action cycle by using the computed model predictive error.

The present invention provides a temperature-compensated crystal oscillator based on digital circuit, a closed-loop compensation architecture is employed to realize the high precision compensation of the crystal oscillator. The output frequency f(T) of the TCXO to be compensated is directly connected with the compensation voltage V_c(T) in real time, and the compensation voltage is fed back to the voltage control terminal of the VCXO to be compensated to compensate, so that the output frequency after compensation is equal to the target frequency signal, thus avoiding the frequency shift of output signal caused by temperature hysteresis, i.e. the discrepancy between the temperature acquired by a temperature senor and the real temperature of the resonant wafer in the prior art.

The invention discloses an optical zero compensation method and system for a laser tracking and aiming device. The method comprises the steps that: the laser tracking and aiming device is adjusted, so that target light spots are located right in front of a four-quadrant detector, and the areas of the target light spots distributed in four quadrants of the four-quadrant detector are the same; after the conditions are met, a feedback control loop is opened, a servo mechanism is locked, and the laser tracking and aiming device is continuously adjusted to rotate around the center axis by 180 degrees; output signals of the four quadrants of the four-quadrant detector after 180-degree rotation are obtained, the misalignment angle of the laser tracking and aiming device is calculated and determined according to the output signals, and the servo mechanism is adjusted according to the misalignment angle. According to the method and system of the invention, the error of the laser tracking and aiming device can be compensated simply and quickly, repeated disassembly and assembly can be avoided, and manpower is saved.

The invention discloses an anti-vibration crystal oscillator, and the crystal oscillator adopts a closed-loop compensation framework based on a digital circuit to realize high-precision compensation of the crystal oscillator. Firstly, an output signal of an acceleration compensation crystal oscillator is divided into two paths by a power divider: one path is outputted, and the other path is sent to a phase detector to extract a phase signal, is converted into a phase value in a binary coding form by an analog-to-digital converter, and then is transmitted into a microprocessor; a pre-stored phase value-compensation voltage value binary coding table is used for looking up a table to obtain a binary code of a required compensation voltage value, and then the binary code of the compensation voltage value is converted into a required compensation voltage by a digital-to-analog converter, and the required compensation voltage is inputted to the voltage control end of the voltage-controlled crystal oscillator, so the oscillator outputs a signal with a stable phase and finally acceleration compensation is realized, and the problem of phase error caused by inconsistency and asynchronism ofacceleration acquired by a sensor and real-time acceleration of a resonance wafer in the conventional acceleration compensation crystal oscillator is solved.