RU2028001C1 - Method of compensation of temperature error of slope of characteristic of accelerometer - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: method is designed for compensating accelerometers with magnetoelectric converter with disc permanent magnet. Method of compensation of temperature error of slope of characteristic of accelerometer incorporating magnetoelectric power converter with disc permanent magnet magnetized in diametrical direction consists in compensation of temperature change of magnetic flux in working gap of power converter with the use of thermomagnetic shunt inserted into magnetic system of power converter. Thermomagnetic shunt inserted into magnetic system of power converter. Thermomagnetic shunt is placed with direction of its layers along neutral axis of magnet, slope of characteristic of accelerometer is measured at two values of ambient temperature, thermomagnetic shunt is set at angle of 90 deg to neutral axis of magnet and slope of its characteristic is measured at same values of ambient temperature, thermomagnetic shunt is turned through angle found by means of calculated relation. EFFECT: improved efficiency of compensation of temperature error. 1 dwg

Description

 The invention relates to measuring equipment, namely to compensation accelerometers with a magnetoelectric power transducer with a disk permanent magnet.

 There is a method of compensating for the temperature error of the steepness of the accelerometer characteristics, which consists in changing the magnetic flux in the working gap of the power converter by changing the magnetic resistance of the working gap due to deformation of the magnetic circuit [1].

 When implementing this method, it is difficult to compensate for the individual temperature error of the slope of the characteristics of an individual device due to the absence of temperature compensation elements that take into account the individual temperature error of the accelerometer.

 Individual compensation of the temperature error of the steepness of the characteristics of an individual device is ensured by the method, which consists in compensating for the temperature change in the magnetic flux in the working gap of the power converter by selecting the cross-sectional area of a thermomagnetic shunt, drawn from several bars of different sections and set by the direction of its layers in the direction of magnetization of the magnet [2].

 But even in this way, it is not possible to precisely compensate for the temperature error due to the finite discreteness of the cross-section of thermal shunts. In addition, the implementation of this method is difficult in relation to power converters with a flat disk-shaped magnet due to the inability to mount a set of thermal shunts.

 The aim of the invention is to expand the application of the method of thermal compensation using thermal shunts and to improve the accuracy of thermal compensation.

, где α_а - температурный коэффициент характеристики акселерометра без термошунта;
α_ш - температурный коэффициент крутизны, вносимый термошунтом;
α_а =

;
Δ Т = Т₂ - Т₁;
α_ш =

.This goal is achieved by using a method of compensating for the temperature error of the steepness of the characteristics of an accelerometer containing a magnetoelectric power transducer with a disk permanent magnet with magnetization in the diametrical direction, which consists in compensating for the temperature change in the magnetic flux in the working gap of the power transducer using a thermomagnetic shunt introduced into the magnetic power converter system by having a thermo-shunt disposed in a neutral direction th axis of the magnet, measured slope of characteristic accelerometer at ambient temperature T _1, the slope of characteristic 'at a second ambient temperature _T2 is set termoshunt direction of the layers 90 ^of to the neutral axis of the magnet, measured by the slope of characteristic _one accelerometer at a first ambient temperature T ₁ , the steepness of the characteristic K ₁ 'at ambient temperature T ₂ , deploy a thermal shunt by the direction of the layers at an angle φ relative to the neutral axis of the magnet, determined by the ratio vision
φ = arcsin

where α _a is the temperature coefficient of the characteristics of the accelerometer without a thermal shunt;
α _W - the temperature coefficient of steepness introduced by the thermal shunt;
α _a =

;
Δ T = T ₂ - T ₁ ;
α _w =

.

 In the position of the thermal shunt, when the direction of its layers coincides with the neutral axis of the magnet, the induction in the working gap of the power transducer at the location of the thermal shunt is zero, therefore, the magnetic flux from the magnet does not pass along the cross section of the thermal shunt. Consequently, the temperature change in the steepness of the accelerometer characteristic is determined only by a change in the magnetic flux caused by changes in the magnet energy and magnetic resistances in the magnetic circuit of the power converter depending on the ambient temperature. Therefore, from the values of the steepness of the accelerometer characteristics at two ambient temperatures, the temperature coefficient of the steepness of the accelerometer characteristics is determined due to a change in the parameters of the accelerometer itself.

When the layers of the thermal shunt are directed at an angle of 90 ^° to the neutral axis of the magnet, the induction in the working gap of the magnet at the location of the thermal shunt is maximum. In this case, the maximum possible magnetic flux for a given cross section of the thermal shunt closes through the thermal shunt, the magnitude of which depends on the ambient temperature. Since, with increasing temperature, the thermo-shunt returns part of the flow to the working gap of the power converter, and the magnetic system of the magnet decreases the magnitude of the magnetic flux, the temperature coefficients of the steepness of the accelerometer characteristics due to changes in the parameters of the accelerometer and thermo-shunt have different signs. Therefore, the difference temperature coefficient of the steepness of the accelerometer characteristic is determined from the values of the steepness of the accelerometer characteristics at two values of the ambient temperature. And since the temperature coefficient of the steepness of the characteristic due to temperature changes in the parameters of the accelerometer is determined by previous changes, the temperature coefficient of the steepness of the characteristics of the accelerometer is determined by the changes in the parameters of the thermal shunt.

From the above it is clear that the temperature coefficient transconductance characteristic of the accelerometer due to temperature changes termoshunta parameter is zero when the direction termoshunta layers of the neutral axis of the magnet and maximum when the direction of the layers 90 ^of to the neutral axis of the magnet. Therefore, within the angle (90 ^o ≅φ≅ ⁰ °) between the direction of the layers and the neutral axis termoshunta magnet has a temperature coefficient transconductance characteristic of the accelerometer, temperature changes termoshuntov defined parameters, which is equal to the temperature coefficient transconductance characteristic caused by temperature changes accelerometer parameters.

 In this case, the total temperature coefficient of the steepness of the accelerometer is zero, and the magnetic flux in the working gap of the power converter is constant and does not depend on the ambient temperature. Therefore, the claimed method eliminates the temperature error of the slope of the characteristic for accelerometers with a magnetoelectric power converter with a disk permanent magnet with a diametrical direction of magnetization, which expands the possibilities of using the method of thermal compensation using thermal shunts.

 Using the calculated ratio, the angle between the direction of the layers of the thermal shunt and the neutral axis of the magnet is determined, at which full thermal compensation is carried out, which increases the accuracy of thermal compensation.

 Elimination of temperature error increases the accuracy of acceleration measurements using an accelerometer.

 The drawing shows a structural diagram of thermal compensation. The direction of the layers of thermal compensator 1, coinciding with its axis 2, is oriented at an angle φ relative to the neutral axis 3 of the disk permanent magnet 4 with a diametrical direction of magnetization. In the working gap of the magnet is a compensation coil 5.

 The operations of the claimed method are as follows.

.At a single value of the ambient temperature T ₁ , a thermo-shunt is placed with the direction of its layers along the neutral axis of the magnet and the steepness K of the accelerometer is measured. To eliminate the additive errors of the accelerometer, the slope is determined by the readings of the accelerometer at two values of acceleration of the opposite sign. For example, to measure K, an accelerometer is installed with the measuring axis in the direction of the gravitational acceleration vector, and the output signal of the accelerometer I 'is measured. Then, the accelerometer is turned so that its measuring axis is directed opposite to the gravitational acceleration vector, and the output signal of the accelerometer I is measured. '' The steepness of the characteristic K is determined from the expression
K =

.

At a different temperature T ₂ , which differs from T ₁ by ΔT, without changing the position of the direction of the thermal shunt layers, measure the steepness K 'of the accelerometer characteristic. The temperature coefficient of slope of characteristic K. is determined.

Again set the ambient temperature T _1, a termoshunt direction of its fibers at an angle ^of 90 to the neutral axis of the magnet, the steepness of characteristics is measured K _1. Then again set the ambient temperature T ₂ and measure the steepness of the characteristics of the accelerometer K ₁ '. The temperature coefficient of slope of the accelerometer characteristic α _{w is} determined. After this, a thermo-shunt is placed by the direction of its layers at an angle φ to the neutral axis of the magnet.

Claims (1)

METHOD FOR COMPENSATING THE TEMPERATURE ERROR OF CRISIS OF THE ACCELEROMETER CHARACTERISTICS, comprising a magnetoelectric power transducer with a disk permanent magnet with magnetization in the diametrical direction, which consists in compensating for the temperature change in the magnetic flux in the working gap of the power transducer using a thermomagnetic input system the fact that they have a thermal shunt with the direction of the layers along the neutral axis of the magnet, measure the steepness K of the characteristic at ambient temperature T ₁ , and then measure the steepness K 'of the characteristic at ambient temperature T ₂ , set the thermal shunt by directing the layers at an angle of 90 ^° to the neutral axis of the magnet, measure the steepness K _{1 of the} accelerometer's characteristic at ambient temperature T ₁ , the steepness K _{1 of the} characteristic at ambient temperature T ₂ and deploy a temperature shunt with the direction of the layers at an angle φ relative to the neutral axis of the magnet, determined by the ratio

Where

the temperature coefficient of steepness of the accelerometer characteristic without a thermal shunt ΔT = T ₂ -T ₁ ;

temperature coefficient of slope introduced by the thermal shunt.

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