84results about How to "Eliminate nonlinear errors" patented technology

The invention discloses a six-dimensional force and torque sensor for measuring large force and small torque of a large mechanical arm. The six-dimensional force and torque sensor comprises a center shaft, a force sensitive element, a base and a strain gage component, wherein the force sensitive element is fixedly connected to the base; the center shaft penetrates through the force sensitive element and the base; the center shaft is in interference fit with the force sensitive element; the strain gage component is attached to the force sensitive element; the force sensitive element comprises four elastic main beams, four elastic auxiliary beams, a regularly octagonal center shaft platform, four fixing platforms, four main floating beams and four auxiliary floating beams; the strain gage component comprises a first strain gage group and a second strain gage group; two opposite elastic main beams in the four elastic main beams are respectively coated with the first strain gage group, and the other two elastic main beams are respectively coated with the second strain gage group; and the center shaft is in interference fit with a through hole of the center shaft platform. The six-dimensional force and torque sensor can improve the rigidity of measuring the force, and can also slightly improve the rigidity of measuring torque.

The invention belongs to the field of tunnel engineering, and particularly relates to an indoor model experience device with an existing tunnel affected by double subway construction. The experience device mainly comprises a subway excavation simulating device, a tunnel model, a strainometer, a displacement support frame, a displacement meter, and the like. A hollow aluminum pipe is arranged in the middle of the tunnel excavation simulating device, a rubber membrane filled with water is arranged on the periphery of the tunnel excavation simulating device, and soil deformation which is caused by the tunnel excavation is simulated by drainage of water with a certain size. The tunnel model is simulated by aluminum alloy pipes, and the outer wall of the tunnel model is pasted with the strainometer in a full-bridge mode to achieve strain measurement on the existing tunnel. The displacement meter is fixed on the displacement support frame, and measurement on longitudinal settlement of the existing tunnel can be achieved. The indoor model experience device with the existing tunnel affected by the double subway construction can conveniently and effectively simulate the existing tunnel deformation caused by the double subway construction of a city, and has important reference value for establishing a tunnel construction security traversing technology standard and an adjacent structure security protective measurement.

The invention discloses a distributed optical fiber temperature sensor which mainly comprises a machine casing and a pulse laser source, a wavelength division multiplexer and an optical switch which are arranged in the machine casing. The optical switch is further connected with an optical fiber box, a reference optical fiber ring is arranged in the optical fiber box, a temperature probe is further arranged on the optical fiber box, and the tail end of the optical fiber ring is connected with an external sensing optical fiber through an optical terminal arranged on the machine casing. The wavelength division multiplexer is further sequentially connected with a photoelectric detection module, a high speed collection card and an industrial personal computer board card. The sensor is low in cost, simple in structure, good in signal to noise ratio, good in stability, reliable and high in temperature resolution. A method for removing a nonlinear error of the distributed optical fiber temperature sensor by utilizing a subsection loss difference compensation method to remove the nonlinear error caused by Raman Stokes and anti-Strokes optical loss difference is further provided. By means of the method, a temperature curve demodulated by the system accords with the actual condition, and temperature measuring accuracy and reliability of the system are improved.

The invention discloses a phase delay extraction and compensation method for PGC phase demodulation. A sinusoidal phase modulation interferometric signal is converted into a digital interferometric signal through an analog-to-digital converter after amplifying and filtering, first-order, second-order and fourth-order harmonics of the digital interferometric signal are subjected to orthogonal downmixing simultaneously, and three pairs of orthogonal harmonic amplitude signals are obtained. Phase delays are extracted from the three pairs of orthogonal harmonic amplitude signals, and corresponding phase delay correction coefficients are calculated out by using the phase delays. The phase delay correction coefficients are multiplied by the absolute harmonic amplitude signal equal to the sum ofthe absolute values of the orthogonal harmonic amplitude signals to obtain new harmonic amplitude signals which are not affected by the phase delays, and then a to-be-measured phase is obtained through antitangent operation. The problems are solved that in the PGC phase demodulation technology, phase delay is difficult to measure and non-linear errors caused by the phase delay are difficult to compensate for in real time, the phase measurement accuracy is improved, and the method is widely applied to the technical field of sinusoidal modulation interference.

The invention belongs to the technical field of optical detection, and particularly relates to a wide-range high-precision facial contour detection device and a detection method of the wide-range high-precision facial contour detection device. The problems of 2 pi blur and leading of non-linear errors occur in the prior art, and in order to solve the problems in the prior art, the wide-range high-precision facial contour detection device is characterized by comprising a laser light source, a bean expanding mirror, a collimating lens, a spectroscope, a standard reference mirror, a charge coupled device (CCD) camera, an image collecting system and a computer. The laser light source is a frequency conversion laser capable of frequency conversion. The wide-range high-precision facial contour detection device is simple, high in reliability and large in measuring range.

The invention discloses a rotating platform supported by air flotation. The rotating platform comprises a workbench, a base plate, a vertical air floatation support mechanism, a rotating centre location mechanism and a driving mechanism. The vertical air flotation support mechanism is used for supporting the workbench on the base plate. The rotating centre location mechanism is used for driving the workbench to rotate along a vertical direction, and determining a rotation centre. The driving mechanism is used for converting the linear motion of a linear motor into the rotary motion. The rotating platform provided by the invention is less in intermediate links, fast in response speed and high in location accuracy, and simultaneously the vertical air flotation support mechanism can eliminate nonlinear error of guide mechanisms like an idler wheel, so that the system location accuracy can be further improved.

The invention discloses a device for testing the torsion and the vibration of a rotor of a revolution vane minitype compressor and a test method. A brush type conducting ring is connected with an armature of the compressor through an installation pan; the armature of the compressor is in spline fit with the rotation shaft of the compressor; the armature and the rotation shaft are axially positioned by a press screw bolt with an axial through hole; the brush type conducting ring is respectively connected two sets of resistance type strain sheets through lead wires; the two sets of resistance type strain sheets are symmetrically bonded on the rotation shaft of the compressor at intervals of 180 degrees along the circumference of the rotation shaft to form in to a four-arm differential bridge to be taken as a sensor for the torsion and the vibration of the rotor of the induction compressor; the change characteristic of the shear force of the torsion and the vibration of the rotation shaft is computed and analyzed by measuring the strain change quantity of the resistance type strain sheets when the rotator rotates; an output linear relation between the strain change quantity of a voltage signal by loading excitation voltage; an outputted torsion and vibration voltage signal is amplified through the adjustment of a dynamic strain amplifier; and change data of the voltage signal is acquired, monitored and analyzed by a data acquisition processor, i.e. the data of the torsion and the vibration of the rotation shaft of the compressor can by obtained by a computer.

The invention discloses a wide-load range, high-precision and low-power consumption current detection circuit. The current detection circuit comprises a cascade current mirror, a power stage output circuit, a detection circuit and a switching circuit and also comprises five metal-oxide semiconductor (MOS) transistors M6 to M10, wherein the cascade current mirror consists of M2 to M5; the power stage output circuit consists of MN1, L and C; the detection circuit consists of MP1 and MP2; and the switching circuit consists of MS1 and MS2. By using the current detection circuit, a nonlinear errorcaused by a bias current is eliminated on the basis of properly increasing circuit complexity and ensuing low power consumption, so that the detection precision is improved on the premise of low power consumption of an improved current detection circuit; therefore, the aim of improving the performance of an overall direct current-direct current (DC-DC) system is fulfilled.

The invention discloses a flexible gyro digital rebalancing device based on DSP. The device comprises a gyro assembly and a digital signal processor; wherein the gyro assembly comprises a gyro, a motor, an X torquer, an X sensor, a Y torquer and a Y sensor; the digital signal processor comprises an A / D convertor, an X-PWM generator and a Y-PWM generator; the gyro is connected with an input circuit, the X sensor and the Y sensor are respectively connected with the A / D convertor inside the digital signal processor through an X error identification circuit and a Y identification circuit; the X-PWM generator and Y-PWM generator inside the digital signal processor are respectively the X torquer and the Y torquer through an X pulse current control circuit and a Y pulse current control circuit; the digital signal processor is connected with the motor in the gyro assembly through a motor power supply control circuit; the digital signal processor is provided with a communication interface. In the invention, signal error of the gyro sensor is directly acquired, thus fundamentally removing non-linear error of the gyro torquer.

The invention relates to a light path compensation based laser heterodyne interference measurement method and a light path compensation based laser heterodyne interference measurement device, belonging to the technical field of laser application. The invention adopts reference light and measurement light which are spatially separated from each other, and a light path compensation design is carried out; meanwhile, the method generates two interference measurement signals with opposite Doppler frequency shifts, and selectively uses the two measurement signals for carrying out interference measurement according to the movement direction and speed of a measured target. The method and the device provided by the invention not only reduces the influence of temperature change on the measurement, but also eliminates the frequency aliasing phenomenon in an interferometer, thus improving the measurement accuracy of heterodyne interference measurement; and furthermore, the problem of the limitation of laser source frequency difference to the measurement speed can be solved.

The invention belongs to the technical field of semiconductors and integrated circuits, and in particular relates to a slope conversion circuit applied to a two-step type integral analog-to-digital converter. The slope conversion circuit comprises an operational amplifier, a pair of sampling capacitors, a pair of parasitic balance capacitors and six switches. During high-level analog-to-digital conversion in the first step, an input slope signal is directly output, and is sampled and held by the operational amplifier and the first sampling capacitor; during low-level analog-to-digital conversion in the second step, the input slope signal is input to the positive input end of the operational amplifier, the operational amplifier transfers the voltage change of the positive input end to a floating pole plate of the second sampling capacitor in a mode that the gain is 1, and the voltage is superposed to the holding voltage in the first step and serves as the output of the slope conversion circuit. According to the slope conversion circuit, gain errors caused by parasitic capacitors in a process of transferring the voltage change of the two-step type integral analog-to-digital converter can be effectively eliminated, and the accuracy and the speed are improved.

The invention discloses a gapped core-type Rogowski coil transformer based on magnetic potentiometer compensation. The gapped core-type Rogowski coil transformer comprises a gapped closed-loop core, a primary coil, a secondary coil, a magnetic potentiometer framework, a magnetic potentiometer coil, an inner-loop-grooved annular shielding box, a first bilateral voltage-regulator tube, a second bilateral voltage-regulator tube, a first operational amplifier, a second operational amplifier, a signal conditioning circuit, a first resistor, a second resistor, a third resistor, an integrating capacitor, a third operational amplifier, an analog-digital converter, a microprocessor and a communication interface. According to the transformer, the sensing error of a gapped core-type Rogowski coil is compensated with a magnetic potentiometer, so that a voltage analog quantity and a digital quantity which are in linear proportional relations with primary current containing harmonic waves can be output. Through adoption of the gapped core-type Rogowski coil transformer, the problems of small output signal and low accuracy in a hollow Rogowski coil are solved; the problem of non-linear errors generated by a core in the gapped core-type Rogowski coil transformer is solved; and accurate sensing of primary current fundamental waves and harmonic components is realized.

The invention discloses a clamp-type dc sensor, which comprises: a clamp-type magnetic core with an exciting winding W1 connected to the output end of an excitation circuit contained a triangular-wave generator and a power amplification push circuit A1, a measurement winding W2 and a feedback winding W4 electric connected with the input / output end of a detection circuit, respectively; and a detection circuit with a signal modulating circuit, a SCM 8051, a DAC, and a power amplification push circuit A2. This invention realizes non-contact online measurement for dc with high accuracy and large range.

The invention discloses a PGC phase demodulation method for compensating carrier phase delay nonlinear errors. A high-frequency sine and low-frequency sine scanning composite modulation method is adopted. The first-order and second-order orthogonal down-mixing is carried out on the sampled composite sinusoidal modulation digital interference signal; two pairs of orthogonal amplitude signals are obtained; a first-order orthogonal amplitude signal and a first-order orthogonal differential signal are used to accurately extract phase delay and compensate the phase delay; the first-order orthogonalamplitude signal and the second-order orthogonal amplitude signal are optimized according to the phase delay to obtain two paths of new amplitude signals which are not influenced by the phase delay,a composite phase is obtained through arc tangent and phase unwrapping operation, and finally a to-be-measured phase is obtained through moving average calculation. According to the method, the problems that the phase delay is difficult to accurately measure and the nonlinear error caused by the phase delay is difficult to compensate in real time in the PGC phase demodulation technology are solved, the phase measurement precision is improved, and the method can be widely applied to the technical field of sinusoidal phase modulation interference.

The invention provides a reference current compensation method for a DAC. The reference current compensation method comprises the following steps: arranging a current compensation unit and the DAC between a reference voltage source and a ground wire in parallel; acquiring an input signal, and determining dynamic reference current of the DAC according to the acquired input signal; generating dynamic compensation current corresponding to the dynamic reference current by the current compensation unit so as to combine the dynamic compensation current with the dynamic reference current into constant current. The invention further provides a reference current compensation circuit for the DAC. The reference current compensation circuit comprises the current compensation unit and a logic control module. According to the method and the circuit which are provided by the invention, the reference current flowing through an internal resistor of the reference voltage source can be compensated, so that a pressure drop generated on the internal resistor is fixed, thereby eliminating an error caused by the change of the reference current.

Characters of the method are that using random action of switch to turn on / off the switching capacitors in DAC with multiple bits so as to introduce random noise to smooth nonlinear distortion caused by mismatch of capacitive component; next, introduced random noise raises background noise in signal bandwidth; then, carrying out noise shaping based on the raised background noise to push noise inside signal bandwidth to outside signal bandwidth so as to raise SNR of system effectively. The invention disclosed whole digit method is in use for correcting non-linear error caused by mismatch of capacitive in order to raise stability of modulator and SNR of converter, which use Sigma-Delta A / D and D / A converters in quantification mode with multiple bits.

The invention provides a hyperboloid lens-based angle sensor and a measuring method thereof. The angle sensor comprises a first photoelectric detector, a second photoelectric detector, a first hyperboloid lens and a second hyperboloid lens, and the first hyperboloid lens is arranged between the first photoelectric detector and a transmitting part. In the process of measurement in which a light beam is transmitted to the same photoelectric detector via a light-transmitting hole, the light beam which emerges from the light-transmitting hole enters the first hyperboloid lens, is transmitted by the first hyperboloid lens, and then enters the first photoelectric detector; and a processing system obtains the rotational angle value of a measured object by processing according to the incident position change value of the light beam received by the first photoelectric detector and / or the second photoelectric detector. The novel angle sensor can continuously measure angle, moreover, the precision is high, and the speed of computation is high.

The invention provides a high-precision magnetic modulation type direct current measuring method. By means of the measuring method, the magnetic flux of a measured coil, the cross section area, the magnetic induction intensity or magnetic flux density of the coil and the magnetic conductivity of annular skeleton magnetic materials are measured. Phi is set to be the magnetic flux of one turn of coil, Psi=Nphi is set to be the total magnetic flux of N turns of coils, S is set to be the cross section area of the coil, B is set to be the magnetic induction intensity or magnetic flux density and mu is set to be the magnetic conductivity of the annular skeleton magnetic materials, a segment of working section is selected in a mu-H curve of the magnetic core material through a formula by selecting configuration parameters, and the inductance of the measured coil and the measured direct current are made to form a linear relation. The non-contact direct current transformer is used to conduct measuring. By means of the high-precision magnetic modulation type direct current measuring method, the linear relation between the magnetic core inductance value and the measured direct current can be achieved, so that the moment for reaching the reference voltage and the measured direct current are made from the linear relation, the nonlinear errors in the existing direct current measuring result are eliminated, and measuring accuracy is improved.

The invention discloses a small flow ultrasonic flow system and a measuring method and belongs to the field of flow detecting and calculating. An MCU module is used for controlling all modules, receiving data of all the modules and carrying out operation. The LCD module is connected with the MCU module and used for displaying data produced by the MCU module. A memorizer is connected with the MCU module and used for conducting bi-directional communication with the MCU module and saving the produced data. The upper computer communication module is connected with the MCU module and used for carrying out bi-directional data exchanging with the MCU module. The GP2 module is connected with the MCU module and used for sending measuring data to the MCU module and receiving an instruction from the MCU module. A time-difference method ultrasonic flowmeter and a compensating measure are adopted, and the effect of the temperature on the sound speed and the water density and the nonlinear errors are eliminated. An arc-shaped sound wedge structure and a manufacturing technology are adopted, and the sound wedge performance is stabilized and is not affected by the temperature or vibration.

The invention belongs to the field of optical heterodyne interference, and discloses an optical heterodyne interference method for removing a non-linear error based on a square wave mean value method. The method comprises the steps that at least three paths of signals are obtained from an optical path where non-linear error interference elements exist, phase angles, on signal frequency elements to be removed, of the periodic non-linear error interference elements of the at least three paths of signals are made to be different in a corresponding circumference angle range or in a corresponding circumference angle range after integral multiples of circumference angles are removed, meanwhile, signals are filtered through a filter in an analog electrical signal channel, a phase difference between each path of measuring signals and a reference signal is computed by the adoption of the square wave mean value method, and then analog-digital conversion, displacement calculation, weighting and iterative processing are conducted so as to remove or restrain the interference elements conveniently. The optical heterodyne interference method for removing the non-linear error based on the square wave mean value method can remove specific harmonic elements of the non-linear error or the interference, the regulation process is very easy, system performance is improved, and cost is reduced.

The invention provides a capacitance compensation circuit for an NMOS input transistor of an operational amplifier. The capacitance compensation circuit is a deep N-well NMOS transistor. The invention further provides an analog-digital converter. A differential signal of the operational amplifier of the analog-digital converter uses the NMOS transistor as an input transistor. The capacitance compensation circuits are arranged at two input ends of the operational amplifier. The structure of the NMOS input transistor of the operational amplifier is the same as that of the deep N-well NMOS transistor. The gate of the deep N-well NMOS transistor is connected with the gate of the NMOS input transistor of the operational amplifier to be used as an input end VP / VN of an input signal of the operational amplifier. The source and the drain of NM1 of the deep N-well NMOS transistor are connected with a P-well and is connected with a positive voltage V1 which is more than a threshold voltage VTHN of the deep N-well NMOS transistor, and the substrate of the NMOS input transistor of the operational amplifier is grounded. The capacitance compensation circuit provided by the invention could enable stray capacitances CCP and CCN of the two input ends of the operational amplifier to be equal and to maintain a relative constant value, thereby improving performance of the operational amplifier or the analog-digital converter.

The embodiment of the invention relates to an AC-DC (Alternating Current-Direct Current) regulator and a regulating method. The AC-DC regulator comprises a transformer and a power tube connected to the main winding side of the transformer, wherein when a voltage corresponding to the current of a main winding is higher than a reference voltage, the grid electrode of the power tube is controlled to be switched off. The AC-DC regulator is characterized by also comprising an integrator, a delay lock ring and a reference voltage regulating circuit, wherein the integrator is used for carrying out first integration on a first auxiliary current coupled by the current of the main winding to obtain a first integration increment, carrying out secondary integration on a second auxiliary current coupled by the current of the main winding within a third duration corresponding to a reference current to obtain a second integration increment, and obtaining a second duration of expecting to raise the current of the main winding to a target current peak on the basis of the first integration increment and the second integration increment; the delay lock ring is used for comparing the first duration of raising the current of the main winding to the peak with the second duration of expecting to raise the current of the winding to the target current peak; and the reference voltage regulating circuit is used for regulating the reference voltage by using a comparing result. According to the invention, the time difference is zero, parasitic switching-off delay errors are eliminated and high-precision constant-current output among products is realized.

The invention discloses a method for eliminating a periodic non-linear error or interference in a signal transmission process, and belongs to the field of signal transmission. According to the method, on signal paths with periodic non-linear errors or interference elements, at least signals on three paths are obtained and phase angles of signal frequency elements to be eliminated, of the periodic non-linear errors or the interference elements on the paths are made to be different in one corresponding circumferential angle range or a corresponding circumferential angle range after integer multiples of circumferential angles are eliminated, and the periodic non-linear errors or the interference elements are eliminated or restrained through a subsequent electronic processing method. The method is capable of eliminating specific harmonic wave elements of the non-linear errors or the interference, the adjustment process is very easy, the performance of a system is improved, and cost is lowered.

The invention belongs to the field of optical heterodyne interference, and discloses an optical heterodyne interference method for removing a non-linear error based on a capacitance charging timing method. The method comprises the steps that at least three paths of signals are obtained from an optical path where non-linear error interference elements exist, phase angles, on signal frequency elements to be removed, of the periodic non-linear error interference elements of the at least three paths of signals are made to be different in a corresponding circumference angle range or in a corresponding circumference angle range after integral multiples of circumference angles are removed, meanwhile, signals are filtered through a filter in an analog electrical signal channel, a phase difference between each path of measuring signals and a reference signal is computed by the adoption of the capacitance charging timing method, and then displacement calculation, weighting and iterative calculation are conducted through analog-digital conversion so as to remove or restrain the interference elements conveniently. The optical heterodyne interference method for removing the non-linear error based on the capacitance charging timing method can remove specific harmonic elements of the non-linear error or the interference, the regulation process is very easy, system performance is improved, and cost is reduced.

The invention relates to a light path balanced type high-speed and high-resolution laser heterodyne interference measurement method and a light path balanced type high-speed and high-resolution laser heterodyne interference measurement device, belonging to the technical field of laser application. The invention adopts reference light and measurement light which are spatially separated from each other, and a light path balance design is carried out; meanwhile, the method generates two interference measurement signals with opposite Doppler frequency shifts, and selectively uses the two measurement signals for carrying out interference measurement according to the movement direction and speed of a measured target. The method and the device provided by invention not only reduce the influence of temperature change on the measurement, but also eliminate the frequency aliasing phenomenon in an interferometer, thus improving the measurement accuracy of heterodyne interference measurement; and furthermore, the problem of the limitation of laser source frequency difference to the measurement speed can be solved.

The invention provides a straightness measurement interferometer system without nonlinear errors and a measurement method. A heterodyne light source adopts light emitted by a monostable frequency laser light source, and a polarization direction is divided into two beams of light through a spectroscope, and the two beams of light pass through two acoustic optical modulators respectively and then are changed into two beams of spatially separated light with different frequencies. The two beams of light pass through a Koesters prism and then are divided into four light beams which are propagated in parallel and are symmetrical in space. The four light beams pass through an interferometer system consisting of a half-wave plate, a combined polarization beam splitting prism, a quarter-wave plate,a wedge angle prism and a wedge surface reflector; when the wedge-angle prism generates straightness displacement in a horizontal direction, optical path information (or phase information) of the twobeams of measurement light is changed, and the straightness error of the wedge-angle prism can be obtained by comparing phase difference changes of the two beams of measurement light signals. According to the method provided by the invention, high-precision measurement of a micro straightness error can be realized.

Disclosed is a synchronous method of a distributed device. The distributed device contains a main control unit and a plurality of signal acquisition units connected with the main control unit. The synchronous method contains the following steps: Step S100, the plurality of signal acquisition unit and the main control unit are controlled for timing and synchronization according to an IEEE1588 clock synchronization protocol; Step S200, the main control unit sends a sampled signal at the beginning of each second, a signal acquired by each signal acquisition unit within each second is respectively numbered, and data acquired by each signal acquisition unit is packaged according to a preset format; and Step S300, the main control unit receives data of the signal acquisition units and controls alignment of data with the same number in different signal acquisition units according to a format, and data packets of the same signal acquisition unit are stored according to the number sequence. By the technical scheme, non-linear errors and fixed errors in the synchronization process are eliminated, and synchronization precision of the distributed device is raised effectively.

The invention discloses a distributed optical fiber temperature sensor, which mainly includes a casing and a pulse laser source arranged in the casing, a wavelength division multiplexer and an optical switch, and an optical fiber box is connected to the optical switch, and a Referring to the optical fiber ring, there is also a temperature probe on the optical fiber box, and the tail end of the optical fiber ring is connected to the external sensing optical fiber through the optical fiber terminal arranged on the casing; the photoelectric detection module, high-speed Acquisition card and industrial computer board, the sensor is low in cost, simple in structure, good in signal-to-noise ratio, good in stability, reliable and high in temperature resolution; the invention also designs a method for eliminating Raman The non-linear error caused by the difference of Stokes and anti-Stokes optical loss achieves the method of eliminating the non-linear error of the distributed optical fiber temperature sensor. This method can make the temperature curve demodulated by the system consistent with the actual situation, thus Improve the temperature measurement accuracy and reliability of the system.