33results about How to "Avoid nonlinear errors" patented technology

The invention relates to a five-axis linkage numerical control machining technology, in particular to a five-axis numerical control machining method based on interpolation of a vector of a cutting tool. The five-axis numerical control machining method comprises the following steps of cutting tool track planning: performing interpolation calculation on the vector of the cutting tool under a workpiece coordinate system while the point position of the cutting tool is planned so as to obtain a cutting tool track equation after the vector of the cutting tool is subjected to interpolation and a cutting tool nose point value and a cutting tool vector under the workpiece coordinate system; double-NURBS (non-uniform rational B-spline) curve fitting: performing fitting on a curve formed by a cutting tool nose point and a second point on the axis of the cutting tool by using a double-NURBS curve fitting method; interpolation calculation: performing interpolation on a formed NURBS curve according to a feeding speed so as to obtain corresponding various axis coordinate values in a machine tool coordinate system; and machine tool kinematical modeling and solving: establishing a corresponding machine tool kinematical equation for a specific machine tool mechanism and finishing conversion between two coordinate systems. The five-axis numerical control machining method based on interpolation of the vector of the cutting tool has the advantages of high machining precision and high surface machining quality.

The invention relates to a five-axis numerical control interpolation method based on smooth compression of tool vectors. The five-axis numerical control interpolation method comprises the following steps: judging whether any two adjacent tool vectors meet the conditions of continuous processing according to a read numerical control processing program; if the conditions of continuous processing are met, carrying out compression interpolation of the tool vectors and interpolation of tool nose position; transforming a tool path to transform the tool nose position and tool vector values under a workpiece coordinate system to each axis coordinate under a machine tool coordinate system by utilizing points obtained after compression interpolation of the tool vectors and interpolation of the tool nose position; and fitting two adjacent points after transformation to generate a smooth curve by utilizing a quintic polynomial curve with continuous second derivative. With the adoption of the five-axis numerical control interpolation method, second order continuity of each component of the tool vectors can be ensured, large change of the tool vectors is avoided, nonlinear error generated by dynamic change of a rotation axis in a linear interpolation method is avoided, and the processing precision is improved.

The invention relates to a device and a method for calibrating a flow-dividing vacuum leaking hole, in particular to the device and the method for calibrating the vacuum leaking hole, the leakage value of which is less than 1*10-8 Pa.m3/s by adopting flow-dividing technology, and belongs to the field of measuring technology. The device consists of the calibrated leaking hole, a valve, an ionization gauge, a small hole, a flow-dividing chamber, a non-evaporable getter pump, an ultrahigh vacuum calibrating chamber, a metering hole, a very high vacuum pumping chamber, an oil-free bi-turbo molecular pump air exhauster set, a quadrupole mass spectrometer, a flow meter, a super-high vacuum calibrating chamber, the metering hole, a super-high vacuum pumping chamber and a common molecular pump air exhauster set. The method adopts a fixed flow method gas micro-flow meter to provide a known gas flow rate, so the measuring range of the flow rate is wide and uncertainty of the measurement is low; and by adopting a flow-dividing method to calibrate the vacuum leaking hole, the method of the invention completely avoids a nonlinear error of the quadrupole mass spectrometer and can precisely calibrate the vacuum leaking hole the leakage value of which is less than 1*10-8 Pa.m3/s.

The invention provides a MINS/GPS ultra-tight integrated navigation system design method. The method comprises the following steps of carrying out time-space difference by using carrier phase measurement to obtain a measurement equation, calculating Doppler frequency shift, assisting a GPS carrier tracking loop PLL, smoothing a pseudo-range outputted by a GPS by using carrier phase measurement, and carrying out Taylor expansion of the pseudo-range; and taking the obtained pseudo-range difference and speed difference as measurement of a system model, designing a combined Kalman filter to estimate a system state, correcting inertial device errors and the strapdown inertial navigation calculation navigation information by utilizing a state estimation result outputted by the Kalman filter, andtaking the corrected strapdown inertial navigation calculation information as the navigation positioning result. The method is advantaged in that the Doppler auxiliary errors caused by low-precisionSINS are avoided, correlation between GPS measurement errors and SINS speed errors is avoided, dynamic performance, the anti-interference capability and the navigation positioning precision of the system are enhanced, and non-linear errors introduced by linear pseudo-range measurement are overcome.

The invention relates to a main board for a thermometer and a thermocouple precision correcting method; the main board comprises a main control circuit consisting of a microprocessor, a dial-up input circuit, an interface circuit with at least two slots and a thermocouple sampling circuit; the invention controls the line structure of the sampling circuit with an A/D conversion circuit, reduces the line interference between digital and analog circuits, adds a zero calibration compensation circuit on the front end of the A/D conversion circuit and improves the accuracy of temperature measurement; the invention has the benefits that a bus-type interface circuit is adopted, and a plurality of interface circuit sockets are arranged to realize the extendibility of functions; the A/D conversion circuit is connected with the control end of the analog circuit, thereby reducing the connecting lines between the digital and the analog circuits, reducing the interference of the analog circuit to the digital circuit, and improving the work reliability; and the invention adds the zero calibration compensation circuit, so that when a zero point tends to be negative, the adjustment is very convenient, thereby preventing nonlinear zero-crossing error, and improving the accuracy of temperature measurement.

The embodiment of the invention provides a measurement circuit, and the circuit comprises a first conversion circuit which amplifies an inputted current signal and carries out the current-voltage conversion; a second conversion circuit, connected to the output end of the first conversion circuit and used for carrying out single-ended-differential conversion on the input voltage signal; a third conversion circuit, connected to the output end of the second conversion circuit and used for carrying out analog-digital conversion on the input differential signal; a control circuit, connected to theoutput end of the third conversion circuit, controlling the measuring circuit and performs operation on the input digital signal; wherein the first conversion circuit comprises an amplifier and a feedback resistor bridged between the inverting input end and the inverting output end of the amplifier, and the feedback resistor enables the first conversion circuit to have a single amplification gain.By using the measurement circuit provided by the embodiment of the invention, a measurement result with higher linearity and accuracy can be obtained.

The invention belongs to the technical field of an internet of vehicles and discloses an internet-of-vehicle data transmission method and system. The internet-of-vehicle data transmission system comprises an image acquisition module, a vehicle speed acquisition module, an oil volume acquisition module, a power acquisition module, a main control module, a data filtering module, a network communication module, a positioning module and a display module. The travel data is filtered and modified through the data filtering module, thereby further improving the accuracy and stability of an algorithmand greatly improving the accuracy of the vehicle data; and meanwhile, through the positioning module, the track of a vehicle to be positioned is matched with the road, then, position deviation obtained through matching is utilized to correct location of nearby vehicles, path matching of the corrected nearby vehicle tracks is carried out again, and the obtained position deviation is utilized to correct the track of the vehicle to be positioned, thereby improving precision of the track of the vehicle to be positioned and improving positioning precision of the vehicle to be positioned on an electronic map. The method can be used for vehicle positioning of the electronic map.

The invention relates to a novel power distribution network capacitance and current measurement method and system. The method comprises the following steps that: S1, a capacitance and current tester receives a configured measurement mode; S2, the capacitance and current tester receives a control signal sent by a remote controller, and measures the capacitance and current according to the control signal to obtain a measurement result; and S3, the capacitive current tester displays and outputs the measurement result. According to the invention, a 10 kV voltage transformer is integrated in the tester, the capacitance and the current are measured through a neutral point, and thus the nonlinear error of the measurement result caused by the use of different voltage transformers is avoided. Meanwhile, the tester has an open triangulation function and a remote control measurement function, supports flexible selection of measurement modes, and is high in measurement efficiency and low in safetyrisk.

The invention belongs to the related technical field of precision displacement measurement, and discloses a suspension contact pin displacement sensor based on differential polarization interference and a detection method, the displacement sensor comprises a differential polarization interference device, a voice coil motor and a suspension contact pin mechanism which are arranged from top to bottom, and the suspension contact pin mechanism is connected to the voice coil motor; the voice coil motor comprises a voice coil motor stator and a voice coil motor rotor which are movably connected, andthe voice coil motor rotor is used for driving the suspension contact pin mechanism to move vertically; the suspension contact pin mechanism comprises a suspension bearing connected to the voice coilmotor rotor and a contact pin shaft movably connected to the suspension bearing; the differential polarization interference device is used for measuring the displacement of the contact pin shaft relative to the suspension bearing to obtain a first-stage displacement amount; the secondary displacement is obtained by measuring the displacement of the voice coil motor rotor relative to the voice coil motor stator, and the measurement result of the measured surface can be obtained by calculating and combining the primary displacement and the secondary displacement. According to the invention, thestability and the reliability are improved, and the measurement range is expanded.

The invention relates to an automatic test device for heating seat rings of toilet bowls. The automatic test device comprises a resistance detection circuit, a sensor detection circuit, a processor and a power circuit. The resistance detection circuit and the sensor detection circuit are independent from each other. External tested devices can be connected into input ends of the resistance detection circuit, output ends of the resistance detection circuit are connected into the processor, external tested sensing devices can be connected into input ends of the sensor detection circuit, and an output end of the sensor detection circuit is connected into the processor; whether the tested devices are normal or not can be judged by the processor according to input signals of the resistance detection circuit and signal input states of the sensor detection circuit; power output ends of the power circuit are electrically connected with power input ends of the resistance detection circuit, the sensor detection circuit and the processor. The automatic test device has the advantages that the heating seat rings of the toilet bowls can be quickly tested by the automatic test device, the test efficiency can be improved, the test complexity can be lowered, and the automatic test device is simple in structure and convenient to operate and is portable.