JP3095443B2 - Two-axis angular velocity / acceleration signal detector and output signal processing device for the detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detector for detecting angular velocity / acceleration by a two-axis angular velocity / acceleration sensor and converting it into an electric signal corresponding to the detected amount, and processing an output signal of the detector. To a device that The device according to the present invention is used, for example, as an inertial guidance device or attitude control device in an aircraft, a flying object, or the like.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show a configuration of an angular velocity / acceleration detector as an example of a conventional type and a configuration of a signal processing unit for processing an output signal thereof. The configuration illustrated is disclosed in Japanese Patent Laid-Open Publication No. 3-54476 (March 1991).
(Published on May 8) "Two-axis angular velocity / acceleration sensor signal processing device".

In FIG. 4, reference numerals 101a and 102a denote sensors for detecting an angular velocity and converting the detected angular velocity into an electric signal corresponding to the detected amount.
Reference numerals 1b and 102b denote sensors for detecting acceleration and converting it into an electric signal corresponding to the detected amount. In FIG. 5, 1a, 1
b denotes an angular velocity / acceleration signal which is an output of the sensor, and the sensor output signal is subjected to pre-filters 2a and 2b to remove extra high-frequency components, and further converted to a digital signal by an analog / digital (A / D) conversion circuit 4. After that, it is taken into the digital signal processor 6.

A digital signal processor 6 includes a sine wave signal (cos / sin signal) generating means 5 and rotational position reference signals 3a and 3a.
b, a digital PLL 61 for synchronizing the phase of the cos / sin signal generator 5, a digital input signal MD from the A / D converter 4, and a digital sine wave signal cos, sin from the cos / sin signal generator 5. Multiplication means 621 and 622, digital filters 631 and 632 for passing only low-frequency components of the output of the multiplication means 621 and 622, and digital temperature information TP obtained by digitizing the temperature information 8a and 8b by the A / D conversion circuit 4. A data calibration unit 9 for obtaining calibration data based on the calibration data; and adders 641, 642, 643 as data calibration means for calibrating the outputs of the digital PLL 61 and the digital filters 631, 632 based on the calibration data.
And

Next, signal processing will be described. The output from the sensor is A / D converted and expressed as an angular velocity / acceleration signal as follows: Ω ₁ = ω _X cos Nt + ω _Y sin Nt A ₁ = a _X cos Nt + a _Y sin Nt. Here, ω _{X and} ω _Y are input angular velocities around the X axis and Y axis, respectively, a _{X and} a _Y are input accelerations in the X axis and Y axis directions, N is a rotation speed of the spin axis, and t is time.
Since Ω ₁ and A ₁ are represented in the same manner, only the angular velocity will be described below.

The multiplication means 621 and 622 perform the following multiplication processing on the input signal MD of the angular velocity digitized by the A / D conversion circuit 4. V _X = Ω ₁ cos Nt = ω _X cos ² Nt + ω _Y sin Nt · cos Nt = ω _X / 2 + (ω _X cos 2Nt + ω _Y sin 2Nt) / 2 (1) V _Y = Ω ₁ sin Nt = ω _Y sin ² Nt + ω _X cos Nt · sin Nt = ω _Y / 2 + (ω _X sin 2Nt−ω _Y cos 2Nt) / 2 (2), and the input angular velocities ω _X / 2 and ω _Y / 2 are obtained. . Note that (ω _X cos 2Nt + ω _Y sin 2Nt) / 2 and (ω _X
sin 2Nt−ω _Y cos 2Nt) / 2 are attenuated through digital filters 631 and 632, respectively.

[0007]

In the above-described conventional angular velocity / acceleration detection and signal processing method, the outputs of the angular velocity / acceleration detectors are only Ω ₁ and A ₁ , respectively. Therefore, the flying object or the like on which the detector is mounted vibrates and the input angular velocity ω _X, ω _Y or the input acceleration a _X, a _Y becomes the rotation speed of 2 or more.
When the double frequency component is mixed, the conventional method has a problem that an error occurs in the output of the detector.

For example, input angular velocity ω _X = 0, ω _Y = Ksin
For (2Nt + φ), equations (1) and (2) are modified as follows. V _X = K / 2 · sin (2Nt + φ) · sin 2Nt = K / 4 · cos φ−K / 4 · cos (4Nt + φ) (1 ′) V _Y = K / 2 · sin (2Nt + φ) ) −K / 2 · sin (2Nt + φ) · cos 2Nt = −K / 4 · sin φ + K / 2 · sin (2Nt + φ) −K / 4 · sin (4Nt + φ) ……………………… (2 ') Of the components represented by equations (1') and (2 '), sin (2Nt +
φ), a term including sin (4Nt + φ), and a term including cos (4
Nt + φ) are digital filters 631,
Attenuated (substantially removed) through 632, but K / 4
The term including cos φ and the term including −K / 4 · sin φ remain without being removed, and the effect appears as a direct current (DC) error.

The present invention has been made in view of the above-mentioned problems in the prior art, and prevents the occurrence of a DC error even when a vibration component including a frequency component twice the rotation speed is mixed in an angular velocity / acceleration input. It is another object of the present invention to provide a two-axis angular velocity / acceleration signal detector capable of improving detection accuracy. Another object of the present invention is to provide a signal processing device capable of suppressing a high-frequency noise component generated when processing the output signal of the two-axis angular velocity / acceleration signal detector.

[0010]

According to an embodiment of the present invention, there is provided a first angular velocity sensor fixed to a rotating shaft rotating at a predetermined rotating speed; Relative to the first angular velocity sensor in a vertical plane
A second angular velocity sensor fixedly disposed at a position shifted by 90 °, detecting two-axis angular velocity and outputting first and second composite vector signals having a phase difference of 90 ° from each other. Is provided.

In the above configuration, the object to be detected is an angular velocity, but this may be configured so that acceleration is to be detected. According to another aspect of the present invention, there is provided an apparatus for processing first and second composite vector signals output from the two-axis angular velocity signal detector and the two-axis acceleration signal detector having the above-described configuration, respectively. Means for digitizing the composite vector signal and a reference signal having the same period as the composite vector signal, and
Means for generating first and second digital sinusoidal signals having a phase difference of .degree., The generated first and second digital sinusoidal signals and the digitized first and second composite vectors Means for multiplying by a signal, digital addition / subtraction means for adding and subtracting the multiplied digital signals, and digital filter means for passing a low-frequency component of the output of the digital addition / subtraction means. A signal processing device is provided.

[0012]

According to the configuration of one embodiment of the present invention described above, an output for instructing a two-axis angular velocity (acceleration) using two angular velocity (acceleration) sensors disposed at positions geometrically shifted by 90 °. (A composite vector signal that is electrically shifted by 90 °). Therefore, even if a vibration component including a frequency component twice as high as the rotation speed is mixed in the input of the angular velocity (acceleration), it is possible to prevent the occurrence of the DC error as described later in detail. This contributes to improving the detection accuracy.

According to another configuration of the present invention, as will be described in detail later, a first composite vector signal multiplied by a first digital sine wave signal (cos) and a second composite vector signal are used. The difference between the vector signal multiplied by the second digital sine wave signal (sin) was taken to produce an output for one axis, and the second composite vector signal was multiplied by the first digital sine wave signal (cos). And the first composite vector signal multiplied by the second digital sine wave signal (sin) can be summed to provide an output for one more axis, so that each output signal component is emphasized. High-frequency noise components are cancelled.

The details of the other structural features and operations of the present invention will be described with reference to the accompanying drawings and embodiments described below.

[0015]

1 shows the configuration of an angular velocity signal detector according to an embodiment of the present invention, together with its output waveform. In the figure, 10
1a, 102a and 103a, 104a are each configured to detect angular velocities in pairs and convert them into electric signals corresponding to the respective detected amounts.
And a second sensor. The first sensor 101a, 102a and the second sensor 103a, 104a are arranged such that their input axes are orthogonal to each other in a plane perpendicular to the rotation (spin) axis, and the rotational speed around the rotation axis is It is fixed so as to rotate at N. Each sensor is a pair of two sensors and outputs signals having different signs, so that they are electrically connected so that a difference can be obtained.

FIG. 2 shows the configuration of an acceleration signal detector according to one embodiment of the present invention, together with its output waveform. In the figure, reference numerals 101b, 102b and 103b, 104b denote first and second sensors, respectively, which detect acceleration in a pair configuration and convert the acceleration into an electric signal corresponding to each detected amount. First sensor 101b, 1
The second sensor 103b and the second sensor 103b are fixedly arranged so as to rotate at a rotation speed N around a rotation axis in the same arrangement as the above-described sensor for detecting angular velocity. Each sensor is a pair of two sensors. In this case, since the sensors output signals having the same sign, they are connected so that an electrical sum can be obtained.

FIG. 3 shows a configuration of a signal processing apparatus according to one embodiment of the present invention. The apparatus shown in FIGS. 1 and 2
2 shows a configuration for processing output signals of the angular velocity signal detector and the acceleration signal detector shown in FIG.
In the figure, reference numerals 11a and 12a denote angular velocity detection signals, 11b and 12b denote acceleration detection signals, and the angular velocity / acceleration detection signals are filtered by extra filters 2a and 2b to remove excess high frequency components. After being converted into a digital signal by the above, the digital signal is taken into the digital signal processor 6a.

The digital signal processor 6a includes a sine wave signal (cos / sin signal) generating means 5 and rotational position reference signals 3a, 3a.
b, a digital PLL 61 for synchronizing the phase of the cos / sin signal generator 5, a digital input signal MD from the A / D converter 4, and a digital sine wave signal cos, sin from the cos / sin signal generator 5. Multiplication means 621 and 622, digital addition and subtraction means 651 and 652 for adding or subtracting the outputs of the multiplication means 621 and 622, digital filters 631 and 632 for passing only low-frequency components of the output of the digital addition and subtraction means, and temperature information 8a. , 8b is A / D
A data calibrator 9 for obtaining calibration data based on the digital temperature information TP digitized by the conversion circuit 4, and adders 641, 642, 643 as data calibrating means for calibrating the outputs of the digital PLL 61 and the digital filters 631, 632 based on the calibration data. And

Next, the signal processing will be described. The output from the detector is A / D converted and converted into an angular velocity / acceleration signal Ω ₁ = ω _X cos Nt + ω _Y sin Nt Ω ₂ = −ω _X sin Nt + ω _Y cos Nt A ₁ = a _X cos Nt + a _Y sin Nt A ₂ = −a _X sin Nt + a _Y cos Nt Here, ω _{X and} ω _Y are input angular velocities around the X axis and Y axis, respectively, a _{X and} a _Y are input accelerations in the X axis and Y axis directions, N is a rotation speed of the spin axis, and t is time.
Since Ω _1, Ω ₂ and A _1, A ₂ are represented in the same form, only the angular velocity will be described below.

Multiplication means 621,622 and addition / subtraction means 651,652
Performs the following addition / subtraction processing on the input signal MD of the angular velocity digitized by the A / D conversion circuit 4. V _X = Ω ₁ cos Nt−Ω ₂ sin Nt = (ω _X cos ² Nt + ω _Y sin Nt · cos Nt) − (− ω _X sin ² Nt + ω _Y cos Nt · sin Nt) = ω _X ... (3) V _Y = Ω ₁ sin Nt + Ω ₂ cos Nt = (ω _X cos Nt · sin Nt + ω _Y sin ² Nt) + (− ω _X sin Nt · cos Nt + ω _Y cos ² Nt) = ω _Y ………………………………………………… (4) Only input angular velocity ω _X, ω _Y Is obtained.

That is, since a high-frequency component proportional to cos 2Nt or sin 2Nt does not appear, even when such a high-frequency component is mixed in the angular velocity / acceleration input, there is an advantage that no DC error occurs in the output of the detector. Can be This contributes to improvement in detection accuracy. Also, the formula
(3), and multiplied by the digital sine-wave signal (sin), in the composite vector signal Omega ₂ and multiplied by the digital sine wave signal (cos) the composite vector signal Omega ₁ as shown in (4) taking the difference between the output V _X of one axis, and multiplied by the complex vector signals Omega ₂ into a digital sinusoidal signal (cos) and multiplied by the complex vector signals Omega ₁ into a digital sinusoidal signal (sin) since the output V _Y of a further one axis taking the sum, each of the output signal component is emphasized, it is possible to cancel the noise component of high frequency.

In the embodiment described above, the signals (11a, 12a, 11b, 12b) from the detector are converted into digital signals by the A / D conversion circuit (4), and the signals are processed in the digital signal processor (6a). However, the signal processing form is not limited to this. For example, using an analog multiplier and an analog adder / subtractor, signal processing may be performed without changing the analog signal. In this case, a method of realizing the cos / sin signal generating means and the multiplying means is described in, for example, Japanese Patent Laid-Open No. 2-41.
No. 005 (Japanese Patent Application No. 63-189656).

[0023]

As described above, according to the present invention, the output after signal processing is configured so as not to include high-frequency components. Therefore, when a frequency component twice as high as the rotational speed is mixed in the angular velocity / acceleration input. However, a highly accurate signal can be obtained without causing a DC error. In addition, since the natural frequency of the low-pass filter for removing high-frequency components can be increased, there is an advantage that a sensor signal having better response characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an angular velocity signal detector as one embodiment of the present invention together with its output waveform.

FIG. 2 is a diagram showing a configuration of an acceleration signal detector as one embodiment of the present invention together with its output waveform.

FIG. 3 is a block diagram showing a configuration of a signal processing device as one embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of an angular velocity / acceleration detector as an example of a conventional type together with its output waveform.

FIG. 5 is a block diagram showing a configuration of a signal processing unit of a two-axis angular velocity / acceleration sensor as an example of a conventional type.

[Explanation of symbols]

11a, 12a ... angular velocity detection signals 11b, 12b ... acceleration detection signals 101a, 102a ... first angular velocity sensors 103a, 104a ... second angular velocity sensors 101b, 102b ... first acceleration sensors 103b, 104b ... second acceleration sensors 4 ... analog / digital (A / D) converter 5 ... sinusoidal signal (cos / sin signal) generating means 6a ... digital signal processors 621, 622 ... digital multiplying means 631, 632 ... digital filter 651, 652 ... digital adder means ω _X, ω _Y ... 2-axis input angular velocity Ω ₁ , Ω ₂ ... angular velocity detection composite vector signal a _X, a _Y ... 2-axis input acceleration A ₁ , A ₂ ... acceleration detection composite vector signal cos, sin ... digital sine wave signal MD ... A / D conversion Output signal of circuit 4 (digitized composite vector signal) REF ... reference signal (having the same period as the composite vector signal)

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-2515 (JP, A) JP-A-62-163915 (JP, A) JP-A-1-206263 (JP, A) JP-A-3-206 61814 (JP, A) JP-A-2-129513 (JP, A) JP-A-3-144308 (JP, A) JP-A-2-236458 (JP, A) JP-A-3-54476 (JP, A) 63-62020 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01P 15/14 G01C 19/02

Claims (3)

(57) [Claims] 1. A first angular velocity sensor (101a, 102a) fixedly mounted on a rotation shaft rotating at a predetermined rotation speed, and a first angular velocity sensor in a plane perpendicular to the rotation axis.
° second angular velocity sensor (103a, 10
4a) and detecting the two-axis angular velocity (ω _X, ω _Y ) and outputting the first and second composite vector signals (Ω ₁ , Ω ₂ ) having a phase difference of 90 ° from each other. Characteristic two-axis angular velocity signal detector. 2. A first acceleration sensor (101b, 102b) fixed to a rotation shaft rotating at a predetermined rotation speed, and a first acceleration sensor (90b) in a plane perpendicular to the rotation axis.
° second acceleration sensor (103b, 10
4b) and detecting the biaxial acceleration (a _X, a _Y ) and outputting the first and second composite vector signals (A ₁ , A ₂ ) having a phase difference of 90 ° from each other. Characteristic two-axis acceleration signal detector. 3. The first and second composite vector signals (Ω) output from the two-axis angular velocity signal detector according to claim 1 and the two-axis acceleration signal detector according to claim 2, respectively.
₁ , Ω ₂ , A ₁ , A ₂ ) which is responsive to a means (4) for digitizing the composite vector signal and a reference signal (REF) having the same period as the composite vector signal. Means for generating first and second digital sine-wave signals (cos, sin) having a phase difference of 90 ° with each other in phase with the reference signal, and the generated first and second digital sine-wave signals (cos, sin); Means for multiplying the digital sine wave signal by the digitalized first and second composite vector signals (MD) (621, 622)
Digital addition / subtraction means (651,652) for adding and subtracting the multiplied digital signals, and digital filter means (631,632) for passing low-frequency components of the output of the digital addition / subtraction means. Signal processing device.