56results about How to "Achieve precise compensation" patented technology

The invention discloses a synchronization and time delay compensation method between base band unit and radio system, wherein a high-speed chain between a base band unit BBU and a radio unit RRU realizes synchronization of BBU and RRU via ascending and descending time marks, at descending direction, via two stages of time delay of BBU and RRU, adjusting the compensation of chain time delay, at ascending direction, using data driving to generate base band receiving interruption to compensate chain time delay. The inventive method can realize the synchronization between base band and radio system, and realize the accurate compensation of time delay. The invention can apply the signals of GSM/EDGE between base band and radio for different transmission protocols, while the invention can be used for data transmission with fixed frame.

The invention relates to a method for head attitude compensation. The method comprises: according to display time of at least two rendered image frames, predicting rendering completion time t1 of a to-be-displayed image frame; according to the t1, calculating display start time t2 of the to-be-displayed image frame; according to the t2, calculating first time, predicting a first time head attitude Q, according to the head attitude Q, rendering the to-be-displayed image frame; according to start time a of any completed display cycle, calculating start time t of a to-be-displayed cycle; according to the t and the display cycle T, calculating second time, to obtain a second time head attitude Q', and according to the Q and the Q', calculating a head attitude compensation matrix; according to the attitude compensation matrix, performing attitude compensation calculation on the to-be-displayed image frame; according to vertex coordinates after attitude compensation and vertex coordinates of the to-be-displayed image frame, calculating a correction coefficient; and according to the correction coefficient, calculating a display image frame after the head attitude compensation. The method and the device accurately compensate head attitude of the to-be-displayed image frame, so that smear phenomenon and dizzy feeling in VR system use are reduced.

The invention discloses an inverter control system and method based on ACSF-MPC and PI dual-mode switching, belongs to the technical field of inverter current control, and the system control method employs dual-mode switching, can achieve the no-static-error adjustment of the system current in a steady state, and employs simple and effective dual-PI control. Meanwhile, a fixed-frequency model is adopted for prediction during dynamic adjustment, optimal switching sequence control is predicted for a grid-connected inverter, a traversal optimization mode is adopted for improvement, an ideal output voltage vector is compared with a module of the difference between center vectors of six sectors to obtain the minimum deviation, the calculation amount during traversal is reduced, and rapid response is achieved. Besides, in the control process, a virtual reference current error compensation value is obtained through improved fuzzy compensation and serves as the compensation amount of the current reference value output by the outer ring PI, and the problems of periodic disturbance and current ripples are solved.

The invention discloses a terahertz SAR high-frequency vibration error compensation method. Terahertz SAR imaging under high-frequency vibration has a pair of echo phenomena, firstly, according to a vibration geometric model of a terahertz SAR airborne platform, the influence of the platform vibration on the instantaneous slant distance of the SAR imaging is obtained, and a echo signal model underthe terahertz SAR high-frequency vibration is established; after the echo is subjected to the distance pulse pressure, the influence of the high-frequency vibration of the platform on the distance walking of the signal is analyzed, and the secondary phase position is introduced, and focusing of the pairing echo is completed by adopting the terahertz SAR high-frequency vibration imaging method based on doppler keystone transformation; and then a wavelet multi-resolution analysis is introduced to carry out platform vibration frequency estimation aiming at the relation between the phase of the imaging result and the vibration parameters of the platform, a vibration amplitude phase is estimated by combining a frequency estimation value with a parameter space projection method, and a phase compensation function is constructed to realize accurate compensation of the terahertz SAR high-frequency vibration error. According to the method, accurate compensation of the terahertz SAR high-frequency vibration error is realized, and the imaging quality of the actual terahertz SAR platform is improved.

The invention relates to a friction welding axial deformation precision control process. The friction welding axial deformation precision control process includes a rotating workpiece 1, a moving workpiece 2, a spindle system 3.1, a rotating member fixture 3.2, a moving sliding table system 4.1, a moving member fixture 4.2, a welding loading mechanism 5, a lathe bed 10.1, a guide rail moving pair10.2, a power-driven system 11, a hydraulic system and connecting line 12, a torque sensor 6, a displacement sensor 7, a pressure sensor 8 and a friction welding control system 9. Based on friction torque jump/axial welding pressure jump determination conditions, the problem of automatic measurement of workpiece axial dimensional precision in the welding preparation process and the problem of accurate compensation of the spacing generated by the rotating workpiece and the moving workpiece in the welding process are solved, the accurate control over the axial shortening amount of the friction welding is realized, and the axial dimensional precision of an axial friction welding workpiece and the quality of friction welding products are improved.

The invention proposes an SAR imaging method, and the method comprises the steps: carrying out the collection of SAR data, range direction compensation, azimuth frequency domain high-order term compensation, azimuth frequency domain high-order phase filtering, azimuth time domain high-order term compensation and azimuth inclination correction, and obtaining an image after focusing. The method is used for aperture data processing, gives consideration to the frequency modulation rate space variant caused by the range envelope and azimuth target position at the same time on the basis of the high-order approximate two-dimensional spectrum, employs a frequency domain high-order phase filtering method for solving, effectively improves the imaging speed, and can meet the requirements of real-timeimaging on the basis that the imaging precision is guaranteed.

The invention discloses a stepless compensating device which mainly comprises a filter, a signal collecting plate, an inversion plate, a control plate and a PWM pulse driving plate. Meanwhile, the invention discloses a stepless compensating method. An FPGA chip is used as a core element, a real-time data collecting technology and a dynamic tracking technology are used for monitoring the electric energy quality of a power distribution system in real time, through a monitoring system, a series of electric energy quality data such as system voltages, frequency, loading currents, THDi, THDu, voltage waveform, current waveform, stepless compensating device output current magnitude and waveform can be checked in real-time, the idle current magnitude output by the device is changed continuously through an inversion circuit, quick and continuous idle power compensating is achieved, through the method, idle currents are compensated timely, and the whole structure has the advantages of being scientific, reasonable, advanced in technology, timely in compensating, high in stability, high in cost performance and the like.

The invention relates to a modeling method for suppressing a hysteresis effect of a fiber-optic gyroscope scale factor model. The method is technically characterized by comprising the following steps of 1, building a relational model of the average wavelength and the temperature of a light source through a test of the model of the average wavelength and the temperature of the light source, and obtaining a normalization coefficient of an influence of the temperature of the light source on a fiber-optic gyroscope scale factor; 2, by a scale factor modeling method based on continuous rotation of a single-axis rate rotary table, performing a fiber-optic gyroscope scale factor modeling test; building a relational model of the fiber-optic gyroscope scale factor and the temperature of a coil; and 3, correcting the relational model of the fiber-optic gyroscope scale factor and the temperature of the coil. According to the method, the effect of suppressing the hysteresis effect of the model can be achieved, so that the modeling and compensation precision of the fiber-optic gyroscope scale factor are improved.

The invention discloses a high-rise fire-fighting unmanned aerial vehicle formation optimization control method and system with disturbance compensation. The method comprises the steps of collecting operation state information of an unmanned aerial vehicle formation; and inputting the collected operation state information of the unmanned aerial vehicle formation into an unmanned aerial vehicle formation optimization control model to obtain a cooperative control strategy of the unmanned aerial vehicle formation, wherein the unmanned aerial vehicle formation optimization control model comprises a distributed Hamilton-Jacobi-Bellman equation without disturbance and a disturbance observer model, the distributed Hamilton-Jacobi-Bellman equation without disturbance takes the minimum performance index as a target to obtain the optimal cooperative control strategy under the disturbance-free condition through solving, external disturbance is estimated through the disturbance observer model, and through the optimal cooperative control strategy under the disturbance-free condition and the estimated external disturbance, the cooperative control strategy of the unmanned aerial vehicle formation is obtained. According to the invention, the performance index is minimized while the formation pattern of the unmanned aerial vehicle formation is kept.

The invention discloses an augmented Kalman filter based satellite interference torque estimation method. The method includes steps: S1, extracting steady-state satellite flywheel rotating speed in anorbital period and satellite inertia angular speed measured by a gyroscope from satellite in-orbit data, converting the flywheel rotating speed into flywheel angular momentum, and subjecting the flywheel angular momentum to numerical difference calculation to obtain an approximate value of a flywheel output torque; S2, taking the approximate value of the flywheel output torque and the satellite inertia angular speed measured by the gyroscope as input of a Kalman filter, taking a satellite in-orbit environmental interference torque as a state quantity, and establishing a state updating equation and a measurement equation of an augmented system to obtain a Kalman filter algorithm of the environmental interference torque; S3, subjecting the augmented system to Kalman filter to obtain an estimated value of the environmental interference torque, and adding the estimated value of the environmental interference torque as a feed-forward signal of a satellite control system into a satellite attitude controller.

The invention belongs to the technical field of the digital image processing, and specifically relates to a SAR single-shot image internal brightness compensation method based on gamma correction. Thecompensation method specifically comprises the following steps: S1, finding a pixel point gray maximum value by traversing an image; S2, acquiring a normalized image; S3, performing gamma correction;S4, performing a difference image, performing the difference image on the normalized image and the corrected image; S5, adjusting the gray level, and multiplying the difference image with the pixel point gray maximum value to obtain the gray-level range of the difference image as [0-255], adjusting a result image of the gray-level, namely the final result image of the algorithm processing; and S6, outputting image: outputting the image after processing in S5. The SAR single-shot image internal brightness compensation method based on gamma correction disclosed by the invention has the featureof realizing the precise compensation of the image brightness, the color uniformity and the preserving information are better.

The present invention provides a two-dimensional coding synthetic aperture radar three-dimensional imaging array deformation error compensation method. The method comprises: performing forward rail direction-intersection rail direction space modulation of echo signals through two-dimensional MURA codes; in the condition that an intersection rail direction array has deformation error and performs slow time change along the forward rail direction, performing downward-looking three-dimensional imaging of two paths of echo signals after modulation; performing interference processing of two three-dimensional complex images, and removing a random initial phase and phase errors generated by the deformation errors; establishing an SAR complex image frequency domain coefficient relation after time-domain echo signal-interference; employing a l1 norm optimization criterion, and performing solution of the relation; and performing inverse transformation of the obtained frequency domain coefficients to a spatial domain, and obtaining a target scene three-dimensional image to equivalently realize array deformation error compensation. The three-dimensional imaging array deformation error compensation method obtains a three-dimensional image with good focusing when the precision of the array deformation measurement system is a wavelength magnitude so as to reduce the precision requirement of the array deformation measurement system.

A self-adaptive control method for reinforcement learning of a brush DC motor belongs to the technical field of motors. The invention aims to provide a non-linear control method for a rotational speedof the brush DC motor, the problems of dead regions, creeping and low-speed instability of the brush DC motor in the rotational speed control process are solved by parameter robustness self-adaptiveon-line identification cogging torque, a non-linear friction force model parameter and a reinforcement learning-based known disturbance estimation compensation strategy. The self-adaptive control method comprises the steps of building a mathematic model of the brush DC motor; performing the robustness self-adaptive control method of the brush DC motor. Differential flatness design-based feedforward and feedback two-degree of freedom control structure is employed. Compared with a traditional dual-ring PI control method, the method has the advantages that introduced feedforward control can act on a controlled object at the moment of a reference input rather than deviation occurring, a non-linear compensation signal is introduced into feedforward, the influence of disturbance on low-speed control of the motor can be prevented, and the rotational speed tracking accuracy is improved.

The invention discloses a method and a device for transmitting an analog electrical signal through an optical fiber and belongs to the field of electric power automation. The device for transmitting the analog electrical signal through the optical fiber comprises a signal sending unit (1) and a signal receiving unit (2) connected with the signal sending unit (1) through the optical fiber. The method for transmitting the analog electrical signal through the optical fiber includes steps that inputting the analog electrical signal to be transmitted and recording; generating a scale signal and sending out; coupling through a waveform mixing module to form a hybrid electrical signal; converting the hybrid electrical signal into a hybrid light signal; transmitting the hybrid light signal; receiving and converting the hybrid light signal; separating the hybrid electrical signal and sending out; measuring the attenuated scale signal and analog electrical signal and sending out; calculating and inspecting scale signal attenuation coefficients; compensating, amplifying and outputting the analog electrical signal. The device for transmitting the analog electrical signal through the optical fiber is capable of realizing the analog electrical signal transmission without attenuation through the optical fiber and is high in transmission precision; the method for transmitting the analog electrical signal through the optical fiber is capable of transmitting the analog electrical signal of an electrical power system without feedback through the optical fiber.

The invention relates to a fiber-optic gyroscope zero offset determination method. The method comprises the following steps: S1, obtaining a zero-bias temperature rise model table and a zero-bias temperature drop model table under a preset temperature change rate; s2, querying a zero-bias heating model table and a zero-bias cooling model table, and obtaining a heating zero-bias value and a cooling zero-bias value corresponding to the current environment temperature of the tested fiber-optic gyroscope; s3, calculating a zero-bias heating model weight and a zero-bias cooling model weight corresponding to the current temperature; and S4, carrying out weighted operation on the temperature rise zero-bias value and the temperature drop zero-bias value corresponding to the current temperature obtained in the step S2, and finally obtaining the gyroscope zero-bias value of the fiber-optic gyroscope at the current environment temperature and the temperature change rate. The weighted zero-bias compensation value can be calculated in real time according to the temperature, the temperature rising and falling trend and the temperature change rate, the problem that a traditional zero-bias compensation method is poor in environmental adaptability is solved, and the method is suitable for zero-bias modeling and compensation of fiber-optic gyroscopes of different models or precisions.

The invention discloses a fiber bragg grating hydrogen sensing system based on amorphous palladium-based alloy. The fiber bragg grating hydrogen sensing system is formed by welding a first fiber bragggrating and a second fiber bragg grating which have different central wavelengths in series, wherein the surface of the second fiber bragg grating is coated with a sensing film layer to form a hydrogen sensitive probe, and the sensing film layer is an amorphous palladium-based alloy film. Byutilizing the principle that the stress and the refractive index are changed after the sensing film layer absorbs hydrogen, the hydrogen concentration in the environment is converted into the offset of the central wavelength of a substrate, and the material has both the reversible hydrogen absorption performance of metal palladium and the excellent hydrogen permeability of amorphous alloy, so that the stability and sensitivity of a sensing system can be greatly improved. The surface of the first grating is exposed and used for temperature measurement and temperature compensation, and the inherent temperature cross sensitivity problem of the fiber grating sensor is eliminated. Aiming at the type ofthe second grating, the invention further provides two sensors loading the hydrogen sensing system based on reflection and transmission spectra respectively.

The invention provides a deformation error compensation and target detection method for a ship-borne radar array based on interference processing, and the method comprises the steps: S1, carrying outthe real aperture imaging of a ground object scene or a moving object through two pieces of echo data of the array at the same moment; S2, carrying out the interference processing of two two-dimensional complex images, and removing a deformation error phase of the array; S3, building a relation between echo signal-reference phase and the product of frequency domain coefficient vectors of the complex images; S4, solving a relation reconstruction image through an l1 norm optimization criterion; S5, carrying out the inverse transformation of the image into a space domain, and obtaining a two-dimensional image of the array after the compensation of a deformation error. In a ground imaging mode, the method can achieve the frequency domain low-pass filtering of the two-dimensional spectrums of the complex images after interference, achieve the inverse transformation of the image into the space domain, and obtain the three-dimensional image of the ground object scene. The method obtains the ground imaging result with the good focusing effect, can remove the defocusing effect caused by the movement of the target, and improves the target detection performance of a radar.

The invention relates to the technical field of motion navigation. One embodiment of the invention provides a zero calibration method and system for a three-axis gyroscope. The zero calibration methodfor the three-axis gyroscope comprises the following steps: obtaining the rotation control quantity relative to the three-axis gyroscope in a preset time period; determining a Z-axis angular velocitychange rate in a parallel gravity direction relative to the three-axis gyroscope in the preset time period; and compensating a zero offset in the parallel gravity direction based on the Z-axis angular velocity change rate and the rotation control quantity. Therefore, the zero offset in the parallel gravity direction is compensated by using the rotation control quantity and the Z-axis angular velocity change rate, the geomagnetic sensor in the traditional technology can be replaced, accurate compensation of the zero offset in the parallel gravity direction is realized, and the manufacturing cost of inertial navigation equipment is reduced.

The invention provides a method, a device and a system for modulating a zero sequence voltage pulse width of a three-phase four-legged APF (active power filter). The method comprises the following steps of solving a zero sequence component according to a reference value of a voltage of midpoints of legs A, B and C of the three-phase four-legged arm APF to a midpoint of a leg N of the three-phase four-legged arm APF; controlling a pulse duty ratio according to a reference value of a voltage of a calculating point N of the three-phase four-legged APF to a point O of a cathode of a direct-current bus capacitor and a switch tube of the leg N; and solving a voltage of the midpoints of the legs A, B and C of the three-phase four-legged APF to the point O of the cathode of the direct-current bus capacitor and a corresponding duty ratio. A zero sequence voltage linear control pulse width modulation strategy is applied to the three-phase four-legged APF. Compared with the traditional 3D-SVPWM (three-dimensional space vector pulse width modulation) strategy, the zero sequence voltage linear control pulse width modulation strategy is easy to implement and can reduce calculation delay and requirements on main frequency; and the response speed of the three-phase four-legged APF can be increased further, the harmonic compensation accuracy of the three-phase four-legged APF can be improved, hardware investment is saved, and the method has an important practical significance on practical degree of a project of the three-phase four-legged APF.