RU2042955C1 - Compensation-type accelerometer - Google Patents

Abstract

FIELD: inertial navigation instruments. SUBSTANCE: accelerometer has sensing element 2 with coil of force sensor 3, feedback amplifier 1, and scaling factor temperature variation compensator made in the form of active one-port 4 with negative input resistance. EFFECT: improved measurement accuracy. 1 dwg

Description

 The invention relates to precision engineering and instrumentation and can be used in all sectors of the economy associated with the development and manufacture of compensation type meters.

 Known accelerometer type compensation, in the feedback link which are introduced compensators for temperature changes in the scale factor of the accelerometer [1] To reduce temperature errors include an electric or magnetic shunt. When using an electric shunt, a shunt electrical resistance of a material with a large positive temperature coefficient is included in parallel with the coil of the force sensor. The scheme of using an electric shunt allows you to more accurately select the compensation for the temperature change of the scale factor due to the simpler installation and dismantling of the thermoresistive shunt compared to a thermomagnetic shunt.

 The known compensator circuit with the inclusion of an electric shunt parallel to the winding of the force sensor has significant non-linearity and, with relatively large changes in temperature, does not give an accurate measurement result.

 The aim of the present invention is to increase the accuracy of compensating for temperature changes in the scale factor of the accelerometer with significant changes in ambient temperature.

 To achieve this goal, in the well-known compensation scheme, an electric shunt made in the form of a resistor with a large temperature coefficient of resistance change is replaced by an active two-terminal device with a negative resistance input, the input of which shunts the winding of the force sensor.

 An active resistance converter built on an operational amplifier can be used as an active two-terminal with a negative input resistance. The use of an active two-terminal device with a negative input resistance as an electric shunt is a significant distinguishing feature, which can significantly increase the accuracy of the accelerometer compensation in comparison with the known schemes.

 The drawing shows a block diagram of an accelerometer with a compensator made in the form of an active two-terminal device with a negative input resistance.

 The compensation type accelerometer includes a feedback amplifier 1, a sensing element 2 with a winding of the force sensor 3, an active two-terminal 4 with a negative input resistance equal to the resistance of the resistor R, shunting the output of the two-terminal 4, current meter 5.

1-

где i ток обратной связи, протекающий в обмотке датчика силы;
i_k ток обратной связи, протекающий в измерительной цепи акселерометра;
r сопротивление обмотки датчика силы;
R сопротивление отрицательного резистора (входное сопротивление двухполюсника). Преобразуем зависимость с учетом того, что
i i_o(1+K θ); r r_o(1+ α˙θ); R const,
i_к= i

1-

(1+Kθ)

1-

При компенсации с точностью до линейных членов имеем:
K

·α
i_к= i

1-

(1-K²θ²) Величина температурной погрешности акселерометра
δi_к=

K²θ² где i_o ток обратной связи в обмотке датчика силы при начальной температуре;
K коэффициент температурного изменения масштабного коэффициента акселерометра;
r_o сопротивление обмотки датчика силы при нормальной температуре;
α- коэффициент температурного изменения сопротивления обмотки датчика силы;
θ- отклонение текучего значения температуры от начального значения.Let us describe the operation of the compensator for the change in the feedback current I from the temperature T. The current in the measuring circuit of the accelerometer
i _k = i

1-

where i is the feedback current flowing in the winding of the force sensor;
i _k feedback current flowing in the measuring circuit of the accelerometer;
r winding resistance of the force sensor;
R is the resistance of the negative resistor (input resistance of a two-terminal device). We transform the dependency taking into account that
ii _o (1 + K θ); rr _o (1+ α˙θ); R const
i _k = i

1-

(1 + Kθ)

1-

When compensating up to linear terms, we have:
K

Α
i _k = i

1-

(1-K ² θ ² ) The value of the temperature error of the accelerometer
δi _k =

K ² θ ² where i _o feedback current in the winding of the force sensor at the initial temperature;
K is the coefficient of temperature change of the scale factor of the accelerometer;
r _o resistance of the winding of the force sensor at normal temperature;
α is the coefficient of temperature change in the resistance of the winding of the force sensor;
θ is the deviation of the fluid temperature from the initial value.

 The use of an accelerometer with the proposed compensator construction scheme will significantly reduce the requirements for changes in the ambient temperature while maintaining accuracy or significantly improve the measurement accuracy with the same changes in the ambient temperature.

Claims (1)

 ACCELEROMETER OF COMPENSATION TYPE, containing a sensing element with a winding of the force sensor, a feedback amplifier, the outputs of which through the current meter are connected to the winding of the force sensor, a temperature coefficient scaler compensator connected in parallel with the force sensor winding, characterized in that, in order to increase accuracy, the compensator made in the form of an active two-terminal with negative input resistance.