472 results about "Zero drift" patented technology

A zero-drift analog memory (ZDAM) cell that indefinitely maintains an output signal at a discrete voltage while the memory circuit is powered, wherein the memory circuit receives an input signal, passes the input signal to a storage element upon receiving an assertion signal, maintains an output signal at a level of the input signal when the assertion signal is removed, and utilizes a zero-drift transfer function feedback loop on the output signal to maintain the output signal. A memory array including a plurality of ZDAM cells and method of operation are also disclosed.

The invention discloses a determined method for an initial gesture on the basis of Doppler optical fiber gyro strapdown inertial navigation system, which comprises continuously collecting data which is output by an optical fiber gyro and a quartz flexible accelerometer after being preheated, processing the data of the gyroscope and the accelerometer which are collected, finishing a rough alignment of the strapdown inertial navigation system, entering into an extractive alignment after the rough alignment is finished, establishing a dynamic base error equation of a marine strapdown inertial navigation system, employing an optimal control filtering theory to design an electric filter, and doing a filtering estimation, extracting information of ship hull gesture misalignment angle to correct the ship hull gesture when a combined extractive alignment is finished, finishing extractive initial alignment, simultaneously obtaining shift estimated value of the gyroscope, and realizing a drift course of the initial alignment. The method of the invention can realize accurate estimation to a zero drift of the optical fiber gyro when the requirement of accuracy and rapidity is guaranteed.

The invention discloses a manifold pre-integration-based visual inertial milemeter posture estimation method and device. After finishing the initialization of the visual inertial milemeter system, themethod comprises: visual inertial data alignment, visual optical flow position posture calculation, inertial pre-integration, visual and inertial joint optimization, window marginalization and aboveprocess repetition so that continuous estimation of camera postures is realized. Compared with the single visual milemeter system, the manifold pre-integration-based visual inertial milemeter system has a higher positioning precision, effectively utilizes inertial information in the milemeter system based on the manifold pre-integration algorithm, inhibits noise propagation of the system and reduces the influence of the inertial zero drift on the positioning accuracy of the milemeter.

The invention discloses a pressure sensor calibration method with a temperature compensation function. According to the method, a zero drifting value and a sensitivity drifting value of a pressure sensor are measured at normal temperature and other temperature points, different pressures at the normal temperature and AD values corresponding to the pressures are stored in a pressure parameter table of the pressure sensor, then a zero drifting value and a sensitivity drifting value of the pressure sensor in a full-temperature range are obtained through a curve fitting method when the pressure sensor works, through calculation, the pressure AD values of the sensor at any temperature are converted into AD values at normal temperature, and finally compensated pressure measuring values are obtained according to the parameter table. According to the method, important parameters, namely the zero drifting values and the sensitivity drifting values of the pressure sensor are directly used, and the calibrated pressure sensor is high in precision and is easy to operate.

The invention relates to a speaker identification method based on neutralization and sound-groove model conversion, the steps comprises (1) extracting voice feature, firstly conducting voice frequency pre-treating which is divided into three parts of sample-taking quantification, zero drift elimination, then extracting reverse spectrum signature MFCC, (2) building emotion model library, conducting Gaussian compound model training, training neutral model according to the neutral voice training of the users, conducting neutralization-emotion model conversion and obtaining emotion voice model by algorithm approach of neutralization-emotion voice conversion and (3) scoring for the voice test to identify the speakers. The invention has the advantages that the technique uses the algorithm approach of neutralization-emotion model conversion to increase the identification rate of the emotive speaker identifying. The technique trains out emotion voice model of the users according to the neutralization voice model of the users and increases the identification rate of the system.

The invention provides a synchronization control method of stern hydraulic work platform lifting for shipping manufacturing technique field, which includes steps: establishing close loop control of hydraulic jacking oil cylinder lifting by rope stretching type displacement sensor and proportion servo valve, constructing hydraulic multi-cylinder close loop synchronization control technique based on Master / Slave control strategy, carrying zero drift control of hydraulic multi-cylinder synchronization lifting system, and realizing self-adapting on-line self-setting of PID parameter based on fuzzy reasoning. The invention realizes high precision synchronization for the hydraulic multi-cylinder of the stern hydraulic work platform, synchronization precision of the hydraulic multi-cylinder is controlled in +-3 mm, character of dynamic control is high, robustness is strong, synchronization lifting of the platform is basically not influenced by environment, production cycle of fixing propeller and rudder blade of shipping can be shortened from one week to one day by using the method, and safety of operation is greatly increased.

The invention discloses a zero-crossing-point accurate detection method for AC voltage signals. The method includes the following steps: firstly selecting a comparatively large hardware filtering time constant to ensure that harmonic waves and random noises which may be included in the AC voltage signals can be filtered comparatively well; using large-time-constant software PQ filtering to extract and eliminate DC drift generated by software and hardware; setting a software judgment advancing quantity so as to offset zero-crossing-point delay caused by hardware filtering; accurately calculating random errors t caused by sampling intervals; and at last, using capture and comparison functions of an embedded microcontroller to realize accurate information of an AC voltage frequency and phase so that accurate phase locking of the AC signals can be realized. The detection method solves a problem of zero drift and phase delay caused by a hardware detection circuit and a software algorithm when zero-crossing-point detection is carried out on the AC voltage signals.

The invention relates to an integrated temperature thin film pressure sensor, which consists of a suction pressure connecting pipe with threads and a seal ring, a sensitive component, an external circuit board, a shell and a socket connector. A sensitive elastomer is provided with a transition layer, an insulating layer, resistive layers (including a strain resistive layer and a temperature sensitive resistive layer), a welding layer and a passivation protective layer, wherein the resistive layers are connected with the external circuit board through conducting wires. The insulating layer of the sensor is formed by superimposing SiO2 and Ta2O5 or superimposing the SiO2 and Al2O3, the strain resistive layer is formed by photoetching a NiCr alloy layer, the temperature sensitive layer is formed by photoetching Ni metal, and the temperature sensitive layer not only can solve the problem of actual temperature measurement, but also can compensate the temperature sensitivity more precisely so that the pressure measurement is more accurate. The integrated temperature thin film pressure sensor adopts an ion beam sputtering process, thus the long-term stability of the sensor is good, the temperature zero drift is minimum and the comprehensive precision is high.

The embodiment of the invention provides a compensation method and device for holder drift, a holder and an unmanned aerial vehicle, and is applied to the technical field of the unmanned aerial vehicle. The compensation method comprises the following steps: through a first image and a second image collected by an image acquisition device on the holder, obtaining a holder drift angle, and controlling the holder to move to compensate the drift angle. According to the compensation method, the technical problem that the estimation and the compensation of the holder drift cannot be accurately carried out when the zero drift of a gyroscope is compensated is solved.

The invention relates to an exoskeleton walking mode identification method based on electromyographic signals. The exoskeleton walking mode identification method based on the electromyographic signal comprises the steps of (1) electromyographic signal collection, wherein an electromyographic electrode is attached to the muscle belly along the selected muscle group muscle fibers, an electromyographic signal sensor is connected with the electromyographic electrode through an electrode buckle, and a single-chip microcomputer fixed to the exoskeleton is connected with the electromyographic signal sensor through a wire and used for collecting the electromyographic signals; (2) electromyographic signal conditioning, wherein after the step (1), surface electromyographic signals collected by the electromyographic electrode are input to the electromyographic signal sensor for signal conditioning; (3) exoskeleton walking mode identification through an SVM-KNN classification algorithm based on threshold segmentation, wherein the surface electromyographic signals processed in the step (2) are input to the single-chip microcomputer for A / D conversion, preprocessing for elimination of zero drift, detection feature extraction initial time, feature extraction and classification through the SVM-KNN classification algorithm based on threshold segmentation, and finally the exoskeleton walking mode is identified.

The invention provides a calibration method, a testing method and a manufacturing method for an optical sensor of a mobile terminal. The calibration method for the optical sensor of the mobile terminal includes the steps of concurrently downloading a calibration plug-in when system software is downloaded through the mobile terminal, then installing the system software on the mobile terminal, providing a testing light source which is provided with a preset light intensity value and correspondingly irradiates the optical sensor, running the calibration plug-in to detect an induction signal generated by the fact that the optical sensor is irradiated by the testing light source, obtaining an induction light intensity value of the induction signal, calculating a calibration parameter according to the induction light intensity value and the preset light intensity value, and accordingly writing the calibration parameter into the mobile terminal. The calibration method is applied to the testing or manufacturing process of each mobile terminal, automatic detection is carried out without peripheral equipment, cost is low, efficiency is high, and as the zero-drift optical sensor and the special light source are adopted, the accuracy is high.

The invention provides a numeral PID controlling method. After scaling, differentiation, and integration are applied to signals collected, the signals are superposed, wherein, the differentiated signals are low-pass filtered and then superposed, one part of the integrated signals are directly extracted and the other part are super low-pass filtered at first and then extracted, and the integrated signals extracted are superposed. Concerning about the requirements of servo system on long time stable working, by reconstructing conventional sections of integration and differentiation, the method can assure the sections of integration and differentiation of validity only within a system working frequency band, meanwhile, by a proper discrete processing, the adoption of Butterworth algorithm designs a low-pass filter and further provides a new numeral PID controller, thus effectively solving the zero drifting problem of PID controller and guaranteeing the long time stable working of the system.

The invention discloses an intelligent pressure transmitter, which is provided with a digital temperature sensor and a pressure sensor. Temperature signals and pressure data can be acquired in real time, the pressure data are converted by an A / D (analog / digital) conversion module and then transmitted to a microcontroller for processing together with the temperature signals, so that temperature compensation, zero drift compensation and nonlinear rectification are realized for the pressure sensor. The intelligent pressure transmitter can overcome the shortcoming of zero drift of a traditional pressure transmitter, and has an excellent zero drift compensation characteristic and a fine time drift suppression characteristic.

The invention relates to an unmanned ship movement control system and method. In the control system, a control module comprises a central controller, a heading controller, a rudder angle controller, a backing controller, a speed controller and an accelerator controller, an information collection module comprises a rudder angle sensor, a speed sensor, a heading sensor, a minigyro, a radar detector and a rudder angel compensator, a power module comprises an engine, a rudder pump device, a water-jet propulsor and a backing pump, and the control system can achieve the functions of trajectory tracking, turning rollover prevention, obstacle avoidance and backing and solves the rudder angle zero drift problem. In the control method, the heading controller is driven to continuously adjust the rudder angle of the rudder pump device through heading angle errors, and operation control of the whole navigation process is achieved; meanwhile, a speed control ring is introduced to assist in long distance target tracking, a rudder angle compensation ring is introduced to overcome rudder angle zero drift in ocean currents, and the minigyro monitors inclination of a hull so as to cooperate with the control module and the power module to achieve safe turn.

The invention relates to a method for calibrating the measuring range of an electronic balance. The method comprises the following steps: a) weighing and recording a first unloaded read number of theelectronic balance; b) weighing and recording the read number of the electronic balance loaded with weights in known mass; c) weighing and recording a second unloaded read number of the electronic balance; d) calculating a new sensitivity coefficient and a zero correction coefficient according to the first and second unloaded read numbers and the loaded read number; and e) updating the sensitivitycoefficient and the zero correction coefficient of the electronic balance. The method for calibrating the measuring range of the electronic balance can simultaneously solve the problems of measuringrange drift and zero drift, and improve the calibration accuracy.

The invention discloses a high-voltage alternating-current circuit breaker arc burning time measuring system and method. A measuring collection system composed of a voltage divider, a current transformer, a transient waveform recorder and the like is utilized, post optimization processing is carried out on the waveform data through data analysis software, the error interference level caused by a ratio error, a zero drift and electronic digital noise is eliminated or substantially reduced, and the distinguishability of an arc voltage component of only tens of volts is substantially improved; in addition, the step characteristic of the arc voltage component before and after arc burning is utilized, starting and ending moments of the jumping of the arc voltage component are calibrated on a voltage waveform, and the purpose of precisely measuring the arc burning time is realized.

The invention discloses a capacitance type sensor with a liquid electrode for measuring the liquid holdup of a multiphase flow, which comprises more than one metal plate with an insulating material coating surface, wherein each metal plate is in contact with the conductive liquid of the measured multiphase flow, and simultaneously, is connected with a measurement circuit by a cathode connector consisting of metal conductors; and the conductive liquid in the multiphase flow serves as the cathode of the capacitance type sensor, and the metal plates with the insulating material coatings form an anode. Therefore, the capacitance and sensitivity of the capacitance type sensor for measuring the liquid holdup of the multiphase flow are greatly improved, the problems of zero drift and ant-interference of the sensor are solved, simultaneously the sensor can be applied to the measurement of the multiphase flows of various flow patterns with flow pattern and size factor-independent measurement results, and is also applied to high-temperature high-pressure occasions.

The invention discloses a subway location method based on an inertial sensor. The location method comprises the steps: (1) collecting starting acceleration of a train through an acceleration sensor of a mobile terminal; (2) determining an initial state of the mobile terminal relative to the train according to gravity acceleration and the starting acceleration, and resolving the acceleration of the train according to the initial state; (3) calculating out a zero-drift vector of an acceleration sensor of the train and a zero-drift vector of a gyroscope sensor of the train; (4) correcting an acceleration component in a train rail direction and calculating out displacement of the train according to the corrected acceleration component in the trail rail direction. According to the location method, high-precision location in a subway can be achieved through a gyroscope of the mobile terminal, an accelerometer of the mobile terminal, an off-line map and an id of a base station cell. The method has the characteristics of being low in cost and high in accuracy, has good application prospect and can solve the problems that an existing mobile terminal map base station is large in location mode error and slow in switch.

The invention discloses an NOx analyzer comprising an infrared light source, a chopper, a detection chamber, optical filters and photoelectric sensor. A separator is arranged between the infrared light source and the chopper; a sealed reference chamber parallel to the detection chamber is arranged between the chopper and the optical filter; infrared light emitted by the infrared light source is divided equally into two bundles of light beams which respectively pass through the detection chamber and the reference chamber through the separator; the optical filters are respectively arranged at light path outlets of the detection chamber and the reference chamber; a sealed optical coupler is arranged at the light path outlet of the optical filter, through which the reference chamber passes; and the light path outlet of the optical coupler leads to the photoelectric sensor which is electrically connected with a processor capable of amplifying and processing an electric signal transmitted by the photoelectric sensor. The invention has the advantages that the influence of water molecule on the measurement is effectively overcome, remarkable zero drift does not exist and a gas detection chamber has stronger corrosion resistance.

The invention provides a monocular vision based IMU (inertial measurement unit) drift compensation method aiming at the problem of failure in application to long-time direction estimation due to error accumulation in direction estimation of an existing IMU. The method includes steps of IMU direction estimation, monocular camera direction estimation and vision assisted IMU error compensation. In a feature point pair set of two adjacent frames of images, a vision-based direction estimation value is obtained according to an epipolar constraint method and led into IMU calibration compensation, so that the problem of IMU long-time error accumulation is solved. The monocular vision based IMU drift compensation method is applicable to static and dynamic error compensation and has advantages of accuracy, stability and zero drift.

The invention relates to a giant magnetoresistance current sensor and relates to a device for measuring currents. The giant magnetoresistance current sensor is composed of an electromagnetic conversion module, a signal amplification module and a feedback compensation module, wherein the electromagnetic conversion module comprises a magnetic core of a magnetism accumulation ring, a primary winding and a giant magnetoresistance chip, the signal amplification module comprises an operational amplifier and a push-pull power amplifier, and the feedback compensation module is a feedback winding. The whole measurement circuit forms a closed loop system, and the giant magnetoresistance chip and the magnetic core of the magnetism accumulation ring form a closed structure. The giant magnetoresistance current sensor overcomes the defects that a giant magnetoresistance current sensor in the prior art is very prone to interference of an external stray magnetic field, temperature drift and zero drift cannot be eliminated completely, and the measurement accuracy is affected by intrinsic magnetic hysteresis existing in a magnetic device.

The disclosed embodiments include a method, apparatus, and computer program product for providing a self-validating mass flow controller or mass flow meter. For example, in one embodiment, a self-validating mass flow controller is disclosed that does not require any software modification to a tool / tool controller in which the mass flow controller is being utilized. In other embodiments, a self-validating mass flow controller is disclosed that does not require any hardware or mechanical changes to an existing mass flow controller. Still, the disclosed embodiments further include a self-validating mass flow controller that is configured to determine valve leak and sensor offset simultaneously for performing real time in-situ correction of a mass flow controller's output for zero offset or zero drift in the presence of valve leak.

The invention discloses a force control method for robotic abrasive belt grinding machining for a blade. The force control method for robotic abrasive belt grinding machining for the blade comprises the following steps: modulation and processing for voltage signals; compensation for a converted force; and a force control strategy. The modulation and processing for the voltage signals comprises thefollowing steps: acquiring the voltage signals of six channels of a sensor; carrying out software filtering on the acquired voltage signals; and converting the filtered voltage signals to force signals. The compensation for the converted force comprises the own zero drift compensation of the sensor and gravity compensation for a robotic end load. The force control strategy comprises hybrid force-position control and PI / PD control. The force control method for robotic abrasive belt grinding machining for the blade is capable of increasing the efficiency of the grinding machining, avoiding thecase of low consistency of manual grinding machining, realizing constant-force grinding machining, and keeping a uniform and consistent removal amount of a surface material, thereby improving the surface consistency of the blade while improving the machining accuracy and surface quality.

The invention relates to a differential capacitance displacement conversion and subdivision method and a capacitive linear displacement measuring system. First, the displacement is solved with the use of a conversion reference of differential capacitance displacement, no modulation, demodulation, amplifier or A / D is needed, and measurement and subdivision are simple and accurate; second, differential capacitance variation is converted into pulse width, a circuit needs no zeroing, no noise, parasitic or zero drift interference exists, and the range is not limited and is only related with the series resistance; third, the capacitive linear displacement measuring system is provided by the use of the method and the circuit, the system is large in range and can be used for performing absolute position measurement, a sensor and a circuit of the system are simple, and the system is fully digital, high in precision and good in stability, can be used in harsh environments with water, oil or dust pollution and is better than an optical grating, a ball grid or the like; and fourth, the sensor, the circuit, a display and the like are integrated into a micro (MEMS) device, the precision is at the nanometer level, motion parameters of the MEMS such as mechanical position, displacement, velocity, amplitude and frequency can be accurately measured, and parameter transformation is remotely controlled.

The invention discloses a piezoresistive sensor for internal pressure detection of an expressway road bed. The sensor comprises a zero temperature compensating circuit (101), a sensitivity temperature compensating circuit (102), a ratio-voltage converting circuit (103) and a zero calibration value storage circuit (104), wherein the zero temperature compensating circuit (101) is used for compensating zero drift caused by temperature, the sensitivity temperature compensating circuit (102) is used for compensating the decreased sensitivity caused by temperature, and the ratio-voltage converting circuit (103) is used for providing a constant current source for a circuit, reducing the decreased sensitivity caused by temperature and magnifying difference-mode voltage output by a piezoresistive sensor bridge. By the aid of the sensor, the defect of a prior piezoresistive sensor in application is overcome, an actual use environment is combined, and output values of the sensor can be corrected.

The invention provides a zero drift self-adaption method for a pressure sensor of an engine. By means of the method, the zero drift problem of the pressure sensor can be effectively solved, and the control reliability is improved. The method comprises steps as follows: whether the rotating speed of the engine is zero is detected; if yes, a detecting value of zero-point voltage of the pressure sensor is acquired; a difference value between the detecting value of the zero-point voltage of the pressure sensor and the theoretical value is acquired; the voltage value detected by the pressure sensor during operation of the engine is corrected by means of the difference value. Self-adaption of zero drift can be realized, influences of zero drift on electrical control of the engine are eliminated, the engine is accurately controlled, and the performance of the engine is optimized. The influences of zero drift on the detecting result can be effectively reduced by means of a simple control program, so that the service life of the pressure sensor is prolonged. Compared with a mode of circuit hardware modification, the method has the advantages that the cost for hardware purchase and time required for circuit modification are saved, and the method is more economical and efficient.

The invention discloses a torque limiting system of a folding-arm type lorry-mounted crane. The torque limiting system comprises a sensor part, a processor part and a performer part, wherein the sensor part consists of a weight sensor, a length measuring sensor and two angle sensors, the processor part calculates the rated lifting capacity under the current working condition according to sensor signals and compares the rated lifting capacity with an actually-measured lifting capacity, and the performer part sends out alarm signals or limits dangerous operations when alarming or limiting conditions are reached. The torque limiting system of the folding-arm type lorry-mounted crane has the advantages that the inconvenience in the input of a rated working curve and incompleteness of curve expression are avoided; the torque limitation under any working condition of lifting from the tail end of a lifting arm can be performed, and the functions are comprehensive; and as the weight sensor is adopted to directly measure weight, the calculation error caused by factors such as zero drift and delay when a pressure sensor is adopted is avoided, and the accuracy is high.

The invention discloses an automatic zero drift-correction ultrasound water meter and a correction method. The apparatus comprises a zero flow auxiliary correction transducer set. The zero flow auxiliary correction transducer set can detect ultrasound wave spreading time difference without the interference of flow, is connected with a signal receiving-sending conversion device via a signal and send data to a signal processing and displaying device. The correction method works in a way that according to time difference detected by a measuring transducer set and an auxiliary transducer set via the signal processing and displaying device. Compared with the prior art, zero drift influence quantity in the measuring result can be eliminated, so ultrasound water meter measuring accuracy can be maintained.

The invention discloses a method for improving the weighing precision of a charging system and a device thereof. The method comprises the following steps of: additionally installing a preset compensation module on a weighing hopper to generate an original weighting value, wherein the standard weight of the preset compensation module is larger than the maximum positive zero drift value and the maximum negative zero drift value of the weighing hopper; computing to obtain the current practical value of the material on the weighing hopper according to the original weighting value and the weighing detection value of the weighing hopper; stopping vibrating a high-level stock bin when the current practical value is near to a set material adding value; and discharging the material out of the weighing hopper after the weighing detection value is stable and invariable. The device corresponds to the method. By being additionally provided with the compensation module, the invention simply and skillfully overcomes the problem that the weighing is inaccurate caused by the zero drift, improves the weighing precision of the charging system, and can not increase the production cost.

Disclosed is a digital signal conditioning chip of a full-bridge and piezoresistive pressure sensor, which mainly comprises a bandgap reference voltage module, an adjustable gain calculation amplifier module and a digital control unit module. The invention is characterized in that a positive temperature coefficient voltage is generated in the bandgap reference voltage module to provide an energizing voltage for the full-bridge and piezoresistive pressure sensor, the digital control unit module is equipped with a memory and an inner clock circuit, the gain in the adjustable gain switch capacity calculation amplifier is confirmed by the digital control unit module according to the parameter of positive temperature coefficient, zero temperature coefficient and zero output value. The digital signal conditioning chip of a full-bridge and piezoresistive pressure sensor has the advantages that the conditioning chip realizes effect compensation of sensitivity, zero drift compensation and adjustment of zero output, and is high in conditioning accuracy and low in cost.