56results about How to "Reduce conversion error" patented technology

A amplitude adjustment device of degital optical circulator based on the FPGA is disclosed, the light come from the light source (S1) is incidengted into the coupler (S3), and two beams are obtained via the coupler (S3), one of the two beams is merotomized into two beams each of which is incidengted into the two ends of the fibre-optical ring (S5) via the optical waveguide modulator (S4), the two beams are synthesized into one beam and interference after one loop circulating the fibre-optical ring (S5) and passing through the optical waveguide modulator (S4); then the beam is incidengted into the detector (S2) via the coupler (S3), the electrical signal which expresses the optical power passes the front amplifying circuit (E1) to be enlarged and filted after the conversion in detector (S2), passes the A / D converter (E2) to complete the analogue / digital conversion to output the degital signal to the signal processing module (E3) which outputs the degital modulating signal to D / A converter (E4), the analog signal outputed is enlarged by the modulation amplifying circuit (E5) and is outputed to the optical waveguide modulator (S4). The invention makes the output voltage alignment circuit of the modulating step wave integrated just in one chip of FPGA processor, not getting involved in the simulation model. The attitude of the square wave uses the digital shift mode directly and is gained from the step wave resetting voltage. The square wave and the step wave is added directly in digital-sum in FPGA instead of adding in analog add circuit.

In an A / D converter circuit having a chopper comparator, only a small number of elements are additionally provided to impart a hysteresis characteristic to the comparator, thereby reducing the conversion errors caused by noise. In a successive approximation type A / D converter circuit having a chopper comparator, one or more amplifier stages are provided to the comparator circuit (CMP), and a feedback capacitor (Cf), which is connected to the input terminal of one of the amplifier stages, is also provided to the comparator circuit (CMP). In the A / D converter circuit, during a first interval, an input analog voltage is taken in, and during a second interval, a voltage, which is in accordance with a potential difference between the input analog voltage and the comparison voltage, is inputted and the input potential is amplified by the amplifier stages. When the output of the comparator circuit changes, a positive feedback is applied through the feedback capacitor to the input terminal of the corresponding amplifier stage, thereby providing a hysteresis of 1 LSB or less.

The invention relates to a shield-tunneling-machine shield-tail-gap visual measurement method. The method comprises the following steps of (1) installing a camera, wherein a height between the camera and a shield-tunneling-machine bottom shield shell is h; (2) shooting original image of a shield tunneling machine during a work process by the camera, wherein the original image include a pipe-sheet upper edge and a pipe-sheet lower edge, and the pipe-sheet lower edge is an upper edge of a shield tail gap; (3) taking a horizontal shaft where a center point of the original image is located as a segmentation line and dividing the original image into a first subimage and a second subimage, wherein the second subimage includes the pipe-sheet upper edge; (4) acquiring the pipe-sheet upper edge from the second subimage, and acquiring a distance between the pipe-sheet upper edge and the center point of the original image in the original image d2; (5) converting the d2 into an actual height h2; and (6) according to the following formula, acquiring the shield tail gap d, wherein the formula is d=h+h2-d3, and the d3 is an actual height of a pipe sheet. Compared to the prior art, by using the method of the invention, the method is simple and a measurement result is accurate and reliable.

The invention belongs to the spacecraft navigation and control field and particularly relates to a quaternion all-angle conversion Euler angle acquisition method facing large attitude maneuver. According to the method, an initial attitude matrix is calculated according to the initial alignment result, and an initial attitude quaternion is acquired; an attitude quaternion at the present time is acquired through update according to strapdown gyroscope output data after pre-processing and an attitude quaternion of a previous time; an attitude matrix of a spacecraft at the present time is calculated according to the attitude quaternion, and three Euler angles of the spacecraft are calculated according to the attitude matrix, namely a yaw angle, a roll angle and a pitch angle; an attitude quaternion of the next time is calculated, Euler angles of the spacecraft at the next time are calculated according to the attitude quaternion of the next time. The method is advantaged in that all-angle conversion is realized, switching among different conversion algorithms is not required, calculation of the quaternion conversion Euler angles is simplified, and the calculation time is further saved.

The invention provides a direct time domain processing method for transient electromagnetic sounding data. The direct time domain processing method comprises the following step of: deducing a large fixed-source loop and long grounding lead analytic expression by using time varying point charge as a basic microelement to obtain a large fixed source loop and long grounding lead analytic solution. The direct time domain processing method for the transient electromagnetic sounding data based on the time varying point charge is used for replacing the traditional processing method for the transientelectromagnetic sounding data based on dipoles, and therefore, errors generated in the process from frequency domain deduction to time domain switching in the traditional method can be reduced, the inherent characteristic of a time domain electromagnetic field is highlighted, and the surveying accuracy of a transient electromagnetic method is greatly improved.

The invention discloses a weak current detecting circuit of a nitrogen-oxygen sensor, which comprises a current-voltage conversion circuit, a differential low-pass filter and an instrument operationalamplifier, which are connected in sequence. The current-voltage conversion circuit is formed by connecting a sampling resistor to a signal loop; the current-voltage conversion circuit is used for converting a current signal collected by a nitrogen-oxygen sensor into a voltage signal of N times; after high-frequency interference is filtered by the differential low-pass filter, the voltage signal is output after being accurately and effectively amplified by an instrument operational amplifier, wherein the value of N is equal to the value of resistance of the sampling resistor. The weak currentdetecting circuit of a nitrogen-oxygen sensor in the invention can accurately amplify the weak voltage signal. Such an instrument amplification circuit has the characteristics of low offset, low output error, high signal-to-noise ratio, high common-mode rejection ratio, high gain and the like.

The invention discloses a time difference measuring method of a time different type ultrasonic flow meter. According to the method, on the basis of measuring the time difference through pulse counting, conversion measuring is performed on the error part of the pulse counting through a phase discriminator, an integrating circuit and an ADC, so that the time difference is measured accurately through the flow meter. According to the method, a clock signal which is output by a flow meter control unit MSP430 is adopted as a pulse counting signal. Counting errors exist in the pulse counting and are converted into voltage through the integrating circuit after being recognized by the phase discriminator. The voltage is transmitted to the ADC inside the flow meter control unit MSP430, and through the combination of an ADC conversion result and a pulse counting result, the time difference of the time difference type ultrasonic flow meter can be finally obtained. According to the method, by the utilization of the ADC inside the time difference type ultrasonic flow meter control unit MSP430 and the clock signal, a timing chip of an existing time difference type ultrasonic flow meter can be omitted, and therefore cost is well reduced.

A multifunctional integrated high-pressure metering device is used for improving metering precision, and the volume and cost of the device are reduced. The technical scheme is that the multifunctional integrated high-pressure metering device comprises a three-phase voltage mutual inductor, a three-phase current mutual inductor, a metering control circuit and a high-voltage switch controlled by anelectric operation mechanism; the three-phase voltage mutual inductor and the three-phase current mutual inductor respectively collect the voltage and current signals of a high-voltage power supply circuit; the metering signals outputted by the three-phase voltage mutual inductor and the three-phase current mutual inductor are connected to the signal input end of the metering control circuit; thehigh-voltage switch is serially connected in the high-voltage power supply circuit; the control end of the electric operation mechanism is connected to the control signal output end of the metering control circuit. The device of the invention is integrally designed; while the metering precision is improved, the repeated setting of functional elements is avoided, so that the volume of the meteringdevice is decreased, and the manufacture cost is reduced.

The invention belongs to the technical field of hydrological data measurement and relates to a three-dimensional attitude based intelligent fish lead dynamic water depth measuring circuit and method. The intelligent fish lead dynamic water depth measuring circuit comprises a water depth pressure sensor, an attitude sensor, a CPU (central processing unit) circuit, a ZIGBEE circuit, a control switch, an antenna and an upper computer. The method includes that the water depth pressure sensor acquires water pressure and water temperature data; the attitude sensor acquires underwater fish lead dynamic attitude data to further obtain a current pitch angle, a roll angle and a course angle of fish lead according to a data settlement fusion algorithm; the water pressure and water temperature data and three-dimensional attitude angle data are encapsulated into a data packet which is then stored in the CPU circuit; the control switch is switched on to send the data to the upper computer through the ZIGBEE circuit and the antenna; the water depth data are corrected in the upper computer through three-dimensional attitude angles under dynamic conditions. The three-dimensional attitude based intelligent fish lead dynamic water depth measuring circuit and method are used for intelligent fish lead dynamic water depth measurement, and the measured water depth data are corrected in real time according to dynamic angles so as to realize dynamic accurate water depth measurement.

The invention relates to an alternating current transformer. The alternating current transformer comprises a magnetic core, a primary winding, a first secondary winding, a second secondary winding, a gain amplification unit, a load element and an auxiliary direct current exciting circuit, wherein the primary winding, the first secondary winding and the second secondary winding are respectively arranged on the magnetic core; the primary winding is connected with a tested circuit; after being serially connected with the gain amplification unit, the first secondary winding is serially connected with the second secondary winding; the second secondary winding is also serially connected with the load element; the auxiliary direct current exciting circuit is used for providing direct current exciting current; and the direct current exciting current is used for generating a magnetic field, so that working magnetic induction intensity of the magnetic core is between one fifth and four fifths of saturation induction intensity of the magnetic core. By the alternating current transformer, the magnetic conductivity of the magnetic core is increased, the conversion errors of the alternating current transformer are reduced, and the precision of the alternating current transformer is improved.

The invention provides an adaptive low pass filter, which mainly comprises a shaping circuit, a frequency voltage conversion circuit and a low pass filter circuit; signals to be detected are divided into two paths, one path of signals are input to the shaping circuit, the input signals are converted into pulse signals, the pulse signals are input to the frequency voltage conversion circuit, the input pulse signals are converted into voltage signals, the voltage signals are input to one end of an analog multiplier of the low pass filter circuit, and the cutoff frequency of the filter is indirectly adjusted through the voltage signals; and the other path of signals are directly input to the other end of the analog multiplier of the low pass filter circuit, so that automatic adaption from the cutoff frequency to the input frequency is realized. The adaptive low pass filter is realized by using the principle of frequency voltage conversion and simultaneously combining the analog multiplier, is simple in circuit structure, good in instantaneity, low in cost and convenient to adjust, and meets the requirement of large-range change of the frequency of the signals processed in different application fields.

The invention provides a voltage time converter and method for reducing parasitic capacitance and power supply influence. The voltage time converter comprises a main sampling network, a compensation sampling network, a discharge network and an over-threshold detection unit; the influence of the traditional VTC parasitic capacitance on VTC output swing is reduced by adopting the compensation sampling network; compensation design is carried out on the sampling common-mode level of the compensation sampling network, thereby reducing the influence of low-frequency disturbance of the power supply voltage on the threshold of the traditional VTC threshold detection circuit. The output swing of the voltage time converter of the invention can reduce the influence of the parasitic capacitance; the voltage common-mode level of the VTC input end is related to the power supply voltage, which reduces the conversion error caused by the influence of the power supply voltage on the threshold, so that the threshold voltage is not affected by the power supply voltage, thereby improving the conversion accuracy and performance.

The invention discloses a geometric spline-based linear projectile model modeling solving method, which comprises the following steps of: expressing a boundary of a linear projectile problem as a geometric spline of a linear combination of a control vertex and a primary function with geometric significance by using parameters, and finishing modeling; taking a geometric spline primary function withthe same boundary representation model as a shape function of displacement and surface force in a boundary integral equation of the linear projectile problem, obtaining a linear equation set throughthe discrete boundary integral equation, building a stiffness matrix and solving to obtain the displacement and the surface force of a boundary control vertex; according to the method, the physical domain boundary of the 2D line projectile problem is modeled through the geometric spline, an accurate conversion method represented by a common model is provided, and the approximation error of the common boundary model in the modeling stage is avoided; a geometric spline basis function is adopted in a boundary integral equation to serve as a shape function for describing boundary physical quantity, and the model conversion time is saved.

The invention discloses an instrumental magnitude conversion method for a star sensor based on an infinite-dimension space. The method comprises the following steps: 1) using an infinite-dimensional vector in the infinite-dimensional space to describe a star spectral illuminance function and a band spectral response function; 2) obtaining the functional relation between the infinite-dimensional vector and the magnitude of each band through modeling analysis; 3) selecting the optimal band combination according to the band selection rule and establishing the corresponding redundant equations; 4) and solving the redundant equations by using the optimization algorithm with limited step size and direction and finally obtaining the instrument magnitude. The redundant equations of the multi-band magnitude data are solved to calculate the instrument magnitude so as to effectively reduce conversion error and improve conversion accuracy. As for the band selection rule, the optimal data source band combination can be automatically selected for different instrument bands so as to have good universality to a certain extent and be popularized for the conversion of other instrument stars of different bands.

The invention relates to an electromagnetic flow velocity flow rate measuring device based on real time attitudes and a measuring method thereof, and belongs to the hydrology data measuring technologyfield; the measuring device comprises a pressure sensor, an electromagnetic flow velocity meter, an attitude sensor, a CPU circuit, a control switch, a LoRa circuit, an antenna and a host computer; the electromagnetic flow velocity meter gathers real time single point current speed; the pressure sensor gathers real time air pressure, water pressure and water temperature data; the attitude sensorgathers real attitude data of an underwater lead fish; the CPU circuit stores real time attitude data, pressure data and flow velocity data, and sends the data to the host computer through the LoRa circuit and the antenna; the host computer parses and fuses to obtain three dimensional attitude angle data and water depth data, and the flow velocity data is combined, thus calculating to obtain the current flow rate data. The method and device employ the electromagnetic flow velocity meter to measure the flow velocity, select the flow velocity data under stable states according to real time altitudes, thus accurately measuring flow velocity and calculating current flow rate; the measuring method and device are suitable for various complex water area environments.

The invention discloses a self-adaptive high-speed SAR-ADC conversion time complete utilization circuit and method. According to the circuit and method for completely utilizing the ADC conversion time, when an ADC enters a maintaining mode, clk _ vcm rises, a trigger DFF1 outputs the sum of the last control bit of a resistor R1 and a control bit needing to be adjusted to the control bit of the current resistor R1, and it is guaranteed that the current comparison frequency is equal to n; the counter is reset after the rising edge of the clk _ vcm is delayed; After entering the comparison mode,the counter counts the current comparison times; For an nbit ADC with redundancy, n times of comparison needs to be carried out, and if m times of comparison are carried out in the previous time, thecurrently needed comparison frequency is Yn = Y (n-1) + m-n. According to the method, the comparison times are counted, and then the comparison times are adjusted in a self-adaptive mode, so that theADC carries out accurate n times of comparison in the whole conversion period, and the conversion error is reduced. Under the condition that the ADC conversion rate is changed, real-time tracking canbe realized, and the conversion rate is improved; In addition, the method is irrelevant to process, power supply voltage and temperature changes and is high in reliability.

A resistor string digital-to-analog converter includes a high-order resistor string, first high-order switches, a high-order decoder, a low-order decoder, and a conversion unit. The high-order resistor string includes a plurality of voltage acquisition points that are coupled through unit resistors. The high-order decoder generates a first high-order control signal in accordance with a high-order bit value, and operates in accordance with the first high-order control signal to bring into conduction a first high-order switch coupled to a pair of voltage acquisition points adjacent to each other through one or more voltage acquisition points. The low-order decoder generates a low-order control signal for controlling the conversion unit. The conversion unit divides a pair of high-order analog voltages output from a pair of voltage acquisition points.

The invention relates to the field of multi-detector coordinate system transformation, in particular to multi-detector coordinate system transformation and error correction methods. Aiming at problems existing in the prior art, the invention provides the multi-detector coordinate system transformation and error correction methods. Aiming at the fact that an FOD detection system mainly depends on a radar detection technology, an image detection technology and a laser detection technology, the invention provides a mutual transformation mathematical model of detector coordinates and a runway global coordinate system and provides a method for calculating the parameters of the transformation model. On such basis, aiming at errors of transformation results, the invention provides the error correction method, so that the coordinate transformation accuracy is improved further. According to the invention, corresponding position information under the detector coordinate system of test points is measured through detectors; the parameters in the coordinate transformation model are solved according to the corresponding relationship; after target coordinates are obtained in the detection, a simplified formula for mutual transformation of detection coordinates of multiple detectors and the standard runway coordinates is calculated out.

The invention discloses a large-span self-anchored steel box girder suspension bridge track lofting and measuring method. The method comprises the steps: controlling elevation with a tower column as the benchmark; conducting lofting along a girder surface to control a base mark, and conducting lofting along the center line of a track line to densify the base mark; obtaining the influence of the girder surface temperature on the elevation, determining a concrete pouring time period according to the influence, and formulating an elevation temperature fitting line; formulating an elevation load fitting line according to the load of later construction; correcting the actually measured surface line shape of the large bridge by using the elevation temperature fitting line, the elevation load fitting line and the track structure design height to obtain a track laying fitting line shape; calculating the structural thickness of the ballast bed according to the height difference between the railsurface and the girder surface, and then laying the ballast bed; erecting track panels section by section, and then laying a track. By arranging the encryption base mark, elevation measurement is facilitated, the stable line type of the bridge is conveniently determined, and measurement control in construction is facilitated; in the track arranging process, a relative elevation difference value fixed control method is used for correction again, and the problem that bridge deck track laying is affected due to the fact that the bridge deck elevation is dynamically changed all the time is effectively solved.

The invention discloses a channel conversion control method of a multi-channel SAR-ADC circuit. The channel conversion control method comprises the following steps that S1, the SAR-ADC circuit is controlled to enter a multi-channel sampling state; S2, controlling SAR (Synthetic Aperture Radar) The ADC circuit enters a sampling holding state; S3, controlling the SAR-ADC circuit to enter a global reset state; S4, controlling the first channel of the SAR-ADC circuit to sequentially enter a reset state and a holding state; S5, controlling the first channel of the SAR-ADC circuit to enter a data quantization state; S6, controlling the SAR-ADC circuit to enter a global reset state; S7, controlling the next channel of the SAR-ADC circuit to sequentially enter a reset state and a holding state; Step S8, controlling the next channel of the SAR-ADC circuit to enter a data quantization state; And repeating the steps S6 to S8 until the data quantification of all the channels is completed. Consistency of conversion time sequences of all channels can be guaranteed, and then conversion errors between the first channel and other channels are reduced.

The invention provides an oral cavity positioner, which includes a bracket, a clamp, a positioning ball and an infrared reflective ball. The connecting part of the fixed part and the positioning part; the clamp is arranged on the fixed part, including a fixed arm, a clamping arm, an adjusting arm and a set screw, and the clamping arm is rotatably installed on the fixed part, and is used to approach the fixed arm by turning Clamp molars or dental arches; the adjusting arm is connected with the clamping arm, and the adjusting arm is provided with a threaded hole; the set screw is threaded on the threaded hole, and one end of the set screw passes through the threaded hole to abut against the fixed part, It is used to drive the clamping arm to rotate by screwing in or out of the set screw; the positioning ball is installed on the fixed part to determine the relationship between the three-dimensional medical image coordinate system and the oral positioner coordinate system; the infrared reflective ball is installed on the positioning part , used to determine the position of the oral locator coordinate system in space.

The invention discloses a resistor type analogue signal processing circuit of a vehicle-mounted external sensor. The resistor type analogue signal processing circuit comprises a catching diode and a reverse connection protection diode which are connected in series between a power source and the ground, the negative electrode of the catching diode is connected with the power source, and the positive electrode of the reverse connection protection diode is grounded; one end of a voltage follower circuit is connected between the positive electrode of the catching diode and the negative electrode of the reverse connection protection diode, the other end of the voltage follower circuit is connected with a resistor type signal end through a first resistor, the first resistor is grounded through a first capacitor and outputs analog voltage through a resistor, and a second resistor is grounded through a second capacitor; the voltage follower circuit can provide a current path for power source short circuit, grounded short circuit and power source reverse connection, protect circuit signal processing safety, improve accuracy of an output power source and reduce conversion errors of analog quantity. The resistor type analogue signal processing circuit of the vehicle-mounted external sensor with existing automobile-level resistors is adopted, so that it is avoided that the resistors are burned because a pull-up resistor is overhigh in power when short circuit appears on a vehicle-mounted storage battery.

The invention provides a device for underwater sound velocity measurement and a use method thereof. The device comprises a sound velocity measuring device, a booster pump and a control device, the sound velocity measuring device comprises a sound velocity measuring container, and a sound wave transmitting transducer, a hydrophone, a temperature controller, a salinity indicator and a laser ranging device which are connected to the sound velocity measuring container; and the control device is connected with the sound wave transmitting transducer, the hydrophone, the temperature controller, the salinity indicator and the laser ranging device. According to the device for underwater sound velocity measurement and the use method thereof, sound velocity measurement under different water depths, different temperatures and different salinity in the ocean can be simulated through the device, the underwater sound velocity error measured in an indirect mode is corrected, and the measurement precision of CTD and other instruments is improved.

The embodiments of the invention provide an oral cavity positioner and a dental implant robot system. The oral cavity positioner comprises a support, a fixing device, a positioning ball and an infrared reflecting ball, wherein the support is of an integrated structure and comprises a fixing part and a first positioning part which are used for extending into an oral cavity and a second positioning part which is used for being exposed outside the oral cavity; the fixing device is arranged on the fixing part and comprises a fixing block, a sliding block, a first fastening piece, a second fastening piece and a positioning piece, a first mounting hole used for being matched with a first anchorage nail is formed in the fixing block, a second mounting hole used for being matched with a second anchorage nail is formed in the sliding block, and the sliding block can slide relative to the fixing block so as to adjust the distance between the first mounting hole and the second mounting hole; the first fastening piece partially extends into the first mounting hole and is used for fixing the first anchorage nail; and the second fastening piece partially extends into the second mounting hole and is used for fixing the second anchorage nail.

The invention provides a network feed-forward control method for thickness control system of a cold rolling mill, which is characterized in that: a thickness control equipment comprises an entrance thickness gauge, Ethernet, a controller and a hydraulic pressing device; wherein, the entrance thickness gauge measures the entrance thickness of strip to the cold rolling mill, and the thickness value is then transmitted to the Ethernet network by using a communication interface of the Ethernet; the controller receives the thickness value by using an Ethernet communicating interface from the Ethernet, after calculation of control algorithm, the controlled variable is then sent to a servo valve to drive the hydraulic pressing cylinder, and a calculation of the controller is finished; the thickness gauge sends entrance thickness values of the strip in sequence, meanwhile the controller receives the thickness data successively for calculation, and the thickness feed-forward control of the cold rolling mill is finished. The invention has the advantages that: as the invention changes the transmission method of a thickness feed-forward channel to digital transmission from analog transmission by utilizing the Ethernet, thus the control precision and anti-interference capability are greatly improved; the connecting cables are reduced; the connecting distance is lengthened, and the trouble diagnosis and restoration capability are obviously strengthened.

A amplitude adjustment device of degital optical circulator based on the FPGA is disclosed, the light come from the light source (S1) is incidengted into the coupler (S3), and two beams are obtained via the coupler (S3), one of the two beams is merotomized into two beams each of which is incidengted into the two ends of the fibre-optical ring (S5) via the optical waveguide modulator (S4), the twobeams are synthesized into one beam and interference after one loop circulating the fibre-optical ring (S5) and passing through the optical waveguide modulator (S4); then the beam is incidengted intothe detector (S2) via the coupler (S3), the electrical signal which expresses the optical power passes the front amplifying circuit (E1) to be enlarged and filted after the conversion in detector (S2), passes the A / D converter (E2) to complete the analogue / digital conversion to output the degital signal to the signal processing module (E3) which outputs the degital modulating signal to D / A converter (E4), the analog signal outputed is enlarged by the modulation amplifying circuit (E5) and is outputed to the optical waveguide modulator (S4). The invention makes the output voltage alignment circuit of the modulating step wave integrated just in one chip of FPGA processor, not getting involved in the simulation model. The attitude of the square wave uses the digital shift mode directly and is gained from the step wave resetting voltage. The square wave and the step wave is added directly in digital-sum in FPGA instead of adding in analog add circuit.

The invention provides a network feedback control method for a thickness control system of a cold rolling mill; a thickness tester sends the outlet thickness value of the belt material measured through the Ethernet communication interface to the Ethernet network; the controller receives the thickness value through the Ethernet communication interface from network, calculating the control algorithm, sending the controlled variable to the servo valve, driving the hydraulic pressure screw down the cylinder, completing a calculation of the control circuit; the thickness tester sends the outlet thickness value of the belt material in sequence, the controller receives the thickness value data in sequence, processing calculation, completing thickness controlling process of the cold rolling mill. The invention has the advantages of converting the analog transmission to the digital transmission of the thickness feedback channel through the Ethernet, greatly increasing the control precision and anti-interference capability, reducing the connection cables, extending the connection distance, significantly enhancing fault diagnosis and restoration capability.