41results about How to "Small linear error" patented technology

The invention discloses a gradient coil of a nuclear magnetic resonance spectrometer. The gradient coil is composed of a main coil and a shielding coil coaxially arranged outside the gradient coil, wherein several groups of the main coil are symmetrically distributed up and down in the axial direction of the coil. Two sets of coil windings, the upper two sets of coils are opposite to the lower two sets of coils, the shielding coil is two sets of upper and lower symmetrically distributed coil windings with opposite winding directions, all winding coils are connected in series, the shielding coil and the main coil A distance of 4.3-5.3 mm is preferably maintained between them, and a heat insulating component is also provided in the inner space of the main coil. The gradient coil realized according to the present invention obviously improves the coil efficiency, and a gradient magnetic field with a strength greater than 50Gs / cm@10A and a linear error less than 0.5Gs@10A can be obtained with a simple algorithm and process, and it can ensure that the gradient field is stable when the temperature changes stability in the experiment.

The invention relates to a two-cantilever large-deformation strain measurement sensor. A left end holder is provided with a left end connecting rod, a right end holder is provided with a right end connecting rod, the right end of the left end connecting rod is provided with a fixing body mounted at the left end in a sleeve, the left end of the right end connecting rod is provided with a wedge-shaped body mounted at the right end in the sleeve, the right end of the fixing body in the sleeve is provided with a spring leaf and a centering / spacing slide rod positioned in the spring leaf, the centering / spacing slide rod is externally provided with a compensating spring, the right end of the centering / spacing slide rod is arranged on the wedge-shaped body, the spring leaf is provided with even-numbered (at least four) resistance strain gages, and all the resistance strain gages form a full bridge which uses a lead wire for output. By using the W-shaped spring leaf, the invention greatly improves the sensitivity; and as both ends of the spring leaf are fixed, the two-cantilever large-deformation strain measurement sensor can still have high antijamming capability and stability even if the external loading force changes a lot. The two-cantilever large-deformation strain measurement sensor provided by the invention has the advantages of high sensitivity, easy calibration process, less linearity error, high antijamming capability, good stability and the like, and can be used as a large-deformation displacement sensor.

The invention discloses a gradient coil design method based on the minimum VRMS error, which is characterized in that the design of the gradient coil satisfies the minimum functional function formed by the square of the VRMS linear error and the weighted sum of coil energy storage. The invention also provides an algorithm flow for designing gradient coils based on the minimum VRMS error. For the spherical imaging area, the present invention adopts harmonic coefficient expansion to calculate VRMS error, which has high efficiency and precision. The present invention is suitable for designing any type of existing gradient coils such as cylindrical gradient coils, flat plate gradient coils, and irregular-shaped gradient coils.

The invention provides a portable detection device and a portable detection method based on a neuromuscular electric stimulation device. The portable detection device comprises a housing, a circuit board, a software system, and a touch screen. The housing comprises a main housing body, key caps, and installation fixing members. The circuit board comprises a relay network, a resistor network, a signal conditioning circuit, a CPU single-chip microcomputer, and a power supply module. By adopting the automatic control, the safety protection, and the circuit conversion of the relay network, the switching of the load resistors having different resistance values of the resistor network, the amplification of the signals of the signal conditioning circuit, and by additionally providing a signal zero point circuit, sampling precision and sampling stability are improved, precision of detected electric parameters and waveforms is higher, and linear errors are reduced. The portable detection device has a simple structure, and is widely used in a medical device detection field and an industrial control field.

The invention discloses a self-shielding gradient coil of a nuclear magnetic resonance spectrometer and a design method thereof. The invention is characterized in that, the self-shielding gradient coil comprises a main coil and a shielding coil which is coaxially arranged on the outer side of the main coil. The windings of the main coil are composed of a plurality of stages of main coil upper windings and main coil lower windings which are symmetrically arranged up and down. The centers of winding wire troughs, the circle radiuses of winding coils and turns per coil, corresponding to the maincoil upper windings and the main coil lower windings, are symmetrically arranged up and down in the one-to-one mode. The windings of the main coil are wound in the winding wire troughs and are arranged in a single-layer winding mode in the axial direction. Each stage of main coil winding corresponds to an independent driving current channel. According to the self-shielding gradient coil and the design method thereof, the series single-channel circuit design is changed into the matrix multi-channel circuit design, and the coil structure is simplified. The optimization difficulty of a target field is reduced. The probability that the actually generated gradient field is deformed and the linearity is not pure due to the winding translation and the interlayer dislocation is reduced.

A plane strain measuring sensor has the characteristics: at least two bolt holes or locating slot holes are processed in top surface axial direction of multi-direction support, radial hole processed on the same plane with lateral face radial direction is corresponding and interconnected to the bolt holes or locating slot holes of top surface, at least two connecting rods has one end separately set in radial hole of multi-direction support and another end linked separately to the sensors on the same plane but different directions. Tested in laboratory and by bridge load test, the invention is proved to have the advantages: rational design, high sensitivity, easy standardization, small linear error, excellent interference killing and dampness feature, good stability, changeable standardization, wide use, apart from these, after linking to static strainometer or dynamic strainometer, it can measure strain on the same plane but different directions of building unit such as highway bridge and railroad bridge and that of metal unit as well.

The invention provides a high-precision dip angle measuring instrument based on an over-sampling technology. According to the high-precision dip angle measuring instrument, a microaccelerometer FXLN8361 is adopted as a measurement element, a high-performance low power-consumption single chip microcomputer MSP430F5529 is adopted as a controller, inclination of the measured face is detected through a biaxial measurement method, and constancy of sensitivity of the dip angle is achieved; through an over-sampling algorithm, the measured minimum angle can be improved to 0.05 degree from 0.8 degree.

Grating type lever structure stylus displacement sensor and measurement method 。 The stylus surface profile measuring instrument and surface shape measuring instrument are instruments that use the stylus scanning method to measure the distance, angle, arc radius and other parameters of the two-dimensional shape of the workpiece surface. The stylus sensor is a surface profile measuring instrument and surface shape measuring instrument. The instrument is an important part used to collect the profile information of the measured surface. The composition of this product includes: sensor substrate （ 1 ） , the sensor base is equipped with a rotary shaft （ 2 ） , sensor lever （3） , grating read head （4） and pen lift mechanism （5） , the front end of the sensor lever is connected to the stylus holder （7） , the arc surface of the tail of the sensor lever sticks the grating scale （6） , the rear end of the sensor lever is connected to the damper through the connecting piece （8） , the stylus holder passes through the stylus （9） Connect the stylus （10） , the measuring rod is equipped with force-measuring adjustment weights （11） 。 The invention is used for measuring workpieces.

The invention discloses a method for measuring the rotor speed of a turbo generator and a device thereof. The method comprises the following steps: converting the rotor speed into a pulse electrical signal through a sensor; carrying out F / V conversion on the pulse electrical signal, wherein U(f) refers to the converted voltage signal, f refers to the pulse electrical signal, f1 and f2 refer to two predetermined pulse electrical signal values, Umax refers to a predetermined voltage value; carrying digital-to-analogue conversion on the voltage signal after the F / V conversion; and converting the voltage signal after the F / V conversion into digital quantity through a data acquisition unit. In the method, F / V conversion is carried out on the pulse electrical signals by stages, with respect to the voltage signal which is converted according to the U(f) = f*k1 linear form in prior art 2, because k is more than k1, the frequency range corresponding to the converted voltage signal in the predetermined scope is small, and the caused linear error is also small, the measurement is insusceptible to interference wave, and the measurement error of the rotor speed is small.

The invention relates to narrowband filtering signal conditioning method and device of an electromagnetic flowmeter. In the prior art, a peak sampling and holding signal conditioning circuit is commonly adopted to amplify a flow signal, the interference noise is amplified together with the flow signal through a broadband signal amplification circuit, and a noise frequency spectrum is shifted or aliased into a frequency band of the flow signal, therefore, the problems of low signal-to-noise ratio, poor resolution ratio and difficult expansion of lower flow measurement limit are caused. In the invention, narrowband filtering signal conditioning is firstly carried out; when a signal reaches a stable state, the sampling is carried out, which just avoids the interference from differential noise, therefore, the differential noise is restricted; and a constant mean magnetizing current source which has constant current mean in each cycle generates a constant mean magnetic field required by a narrowband filter conditioning technology, that is to say, the closed loop feedback conditioning to the constant mean current source is realized by sampling and comparing. The invention is used for filtering the superposed interference noise of the flow signal and improves the performance of the electromagnetic flowmeter, thereby expanding the lower flow measurement limit and realizing the accurate micro-flow measurement.