RU2055367C1 - Device determining accelerations - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: device is inserted with quantizer 5 of output signal of angle transducer 2, scale factor correction unit 8 and divider 9 which dividend input is connected to output of scale factor multiplier 7 and divider input is linked to output of correction unit coupled by input to output of quantizer. Output of the latter is connected to input of double differentiation unit 6. Divider output is output of device. EFFECT: increased accuracy of determination of accelerations, for example of flying vehicles. 2 dwg

Description

 The invention relates to measuring technique and can be used to determine acceleration with increased accuracy, for example, aircraft.

Known pendulum positional accelerometers with various suspensions containing an inertial mass made in the form of a pendulum with an axis of rotation fixed relative to the housing, a feedback device consisting of an angle sensor, a power torque sensor, a feedback amplifier, and a flowing current (voltage) in the feedback circuit coupling is proportional to acceleration [1]
A common drawback of such accelerometers is the limited accuracy, sensitivity and ranges of measured accelerations.

Known pulse inertial accelerometers, sensitive elements (SE) which are made in the form of a ball placed in the cavity of the housing, containing a contactless suspension system, an electronic control unit to return the ball to the center of the cavity, a system of displacement sensors in the form of measuring coils and digital units for double signal differentiation with ball motion sensors [2]
The disadvantages of such devices are the complexity of manufacturing technology and the limited movement base.

Closest to the proposed device according to the principle of operation and design are pendulum sensing elements, called measuring transducer heads (IPG), operating in a pulse-inertial mode, including the mode of return and holding the CE in the initial position under the influence of power control and the measurement and transformation mode output signal from an angle sensor proportional to the angle of rotation of the pendulum by double differentiation and multiplication by a scale factor. Such a device comprises a pendulum sensing element, an angular position sensor and a power torque sensor mounted on the axis of rotation of the pendulum, an electronic control unit for returning the pendulum, an electronic control unit for returning the pendulum to its original position relative to the housing, a double differentiation unit, connected at the input to the output of the angle sensor, and the output to the block multiplication by a scale factor [3]
The disadvantages of this device are the small angle of rotation and the decrease in the accuracy of measuring acceleration with increasing angle of rotation of the pendulum.

 The aim of the invention is to increase the accuracy of determining acceleration while increasing the range of the angle of rotation of the pendulum.

 The goal is achieved by the fact that a quantizer of the output signal from the angle sensor, a scale factor correction block and a division block are introduced into the device, the dividend input of which is connected to the output of the multiplication unit by a scale factor, and the divider input is to the output of the correction block, by the input connected to the quantizer output, the output of which is connected to the input of the double differentiation unit, and the output of the device is the output of the division unit.

 In FIG. 1 shows a block diagram of a device; figure 2 is a structural diagram of a correction block.

 The device consists of a pendulum sensing element (SE) 1, a sensor 2 of the angle of rotation of the SE, a power sensor 3 of the moment, an electronic unit 4 for controlling the return of the SE to its original position, a time quantizer 5, a double differentiation unit 6, a scale factor multiplier unit 7, a unit 8 correction scale factor block 9 division.

 The sensor element 1 is an unbalanced pendulum with mass m located at a distance l from the axis of rotation mounted on suspensions with minimal friction. On the axis of rotation of the pendulum are installed, for example, a power electromagnetic sensor 3 of the moment, which provides control of the return of the pendulum to its original position when current flows through the winding, and a photosensor 2, from which the voltage U (current) is proportional to the angle of rotation of the pendulum.

 The electronic unit 4, according to the “Return” signal, generates, for example, relay control for returning the CE to its original position by connecting the power sensor 3 of the moment to the current source for a certain time, quantizer 5 performs amplitude-pulse modulation with a period T. The quantizer can also perform an analog digital converters.

U₁=

{U(KT)-2U[(K-1)T]+U[(K-2)T]

U(KT)
Блок 7 умножения обеспечивает получение
U₂ K₁U₁ (2) где К₁ масштабный коэффициент, например, равный J/ml,
J момент инерции;
ml маятниковость маятника.Block 6 double differentiation implements, for example, the dependence

U ₁ =

{U (KT) -2U [(K-1) T] + U [(K-2) T]

U (KT)
Block 7 multiplication provides
U ₂ K ₁ U ₁ (2) where K _{1 is a} scale factor, for example, equal to J / ml,
J moment of inertia;
ml pendulum pendulum.

Block 8 correction of the scale factor implements the dependence
K ₂ 2cos (U (K-1) T cos (U ([K-2) T]), (3) where U [(K-1) T] and U [(K-2) T] past discrete value signal from the 2 angle sensor.

In FIG. 2 shows a block diagram of a correction block corresponding to dependence (3). The correction block contains delay elements T (memory) by T _s , two blocks for calculating the cosine, a multiplier by a factor of two, and an adder with direct and inverse inputs.

Block 9 division produces the value of the acceleration acting on the SE by dividing the signal U ₂ by the signal K ₂ from the correction block.

 The device operates as follows.

By the “Return” command, the control unit 4 connects the power source to the moment sensor 3 and the pendulum, overcoming an external influence, rotates by a certain angle until it contacts the case and can be held in its original position until the “Return” command is removed. On the trailing edge of this command, quantizer 5 is launched with a short time delay necessary to eliminate the influence of the self-induction current on the movement of the pendulum that occurs in the winding of the torque sensor when the power is turned off. This is the delay time τ ₃ (3-4) τ, where τ L / R is a constant time due to the inductance L of the winding and the active resistance R of the self-induction current loop. The output of quantizer 5 is followed by pulses through each T _s , the amplitude of which is equal to the value of the output signal from the angle sensor.

Upon receipt from the quantizer of the first three and subsequent pulses in the form
U [(K-2) T] U [(K-1) T] U (KT),
U [(K + 1) T] U [(K + 2] T] the pulses equal to the double derivative in amplitude follow the input of block 6. These pulses are transmitted through the multiplication block 7 to the input of the divisible division block 9, and the input of the divider is a corrective impulse from block 8, which implements dependence (3). One or several pulses, equal in amplitude to the measured acceleration, follow from the output of the divider during the movement of the pendulum from the initial initial position to the final position.

Obviously, dependencies (1), (2), (3) and division can also be implemented with a digital special computer based on a microprocessor. In this case, during the movement of the pendulum, one can determine the acceleration several times, and to further increase the accuracy, calculate the average value. For this, it is necessary to increase the angle of rotation of the pendulum and reduce the discreteness period T to the minimum possible value. In this case, at first, as much information as possible about the values of the angle of rotation of the pendulum every T _s should be accumulated, and then it should be worked out according to dependences (1) (3) and averaged.

Claims (1)

 A DEVICE FOR DETERMINING ACCELERATION, comprising a pendulum sensing element, an angular position sensor and a power torque sensor mounted on the axis of rotation of the pendulum, an electronic control unit for returning the pendulum to its original position relative to the housing, a double differentiation unit, at the input connected to the output of the angle sensor, and at the output - to the unit of multiplication by a scale factor, characterized in that a time quantizer of the signal from the angle sensor, a scale factor correction unit and a div a dividend whose input is connected to the output of the multiplication unit by a scale factor, and the input of the divider to the output of the correction unit, at the input of a quantizer connected to the output, the output of which is connected to the input of the double differentiation unit, and the output of the device is the output of the division unit.

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