JPH1151758A - Motion detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect not only heaving but also swaying and surging by containing a plurality of BPFs with different pass frequency bands in a calculation part for calculating speeds in horizontal and vertical directions of an object to be measured by integrating acceleration. SOLUTION: Horizontal acceleration Ax and Ay and vertical acceleration Az being outputted from an acceleration detector are supplied to a calculation part with the same configuration and function for integrating and horizontal speeds Vx and Vy, a vertical speed Vz, horizontal displacement Px and Py, and vertical displacement Pz are outputted. Each calculation part has a plurality of BPF/integration parts 211-213 and an output selection part 241. For example, a calculation part in an X-axis direction inputs the horizontal acceleration Ax and the speed Vx in the X-axis direction and the displacement Px are supplied to the output selection part 214. The output selection part 214 corresponds to the frequency of the motion of an object to be measured for selecting and outputting either of the output of three BPF/integration parts 211-213.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion detecting device for detecting a periodic motion of a ship, a floating structure on water, and the like, and more particularly, to a motion detecting device for detecting heaving, swaying and surging. About.

[0002]

2. Description of the Related Art In order to safely land or take off an aircraft, helicopter or the like on a ship or a floating structure above water, heaving (HEAVE: vertical movement) and swaying (SWAY: left and right movement) of takeoff and landing points are required. ) And surging (SURGE). In a navigation device mounted on a navigation body such as a ship, rolling, pitching and yawing are detected, but heaving, swaying and surging are not detected.

Referring to FIG. 6, an example of a conventional heaving motion detecting device for a ship will be described. This example is disclosed in Japanese Patent Application No. 53-27270 (Japanese Patent Application No. 58-42) filed on March 10, 1978 by the same applicant as the present applicant.
No. 414, Japanese Patent No. 12212467), for details, see the same application.

[0004] The heaving motion detecting device has an accelerometer 1 having an input axis extending in a vertical direction V, and roll shafts 2 and 2 'mounted on both sides thereof. Is equipped with roll bearings 3, 3 '(only 3' is shown). That is, the roll shafts 2, 2 'are mounted on the inner races of the roll bearings 3, 3'. Roll bearing 3,
3 'is attached to the supports 4 and 4' on both sides,
4 'is mounted on the base 6.

[0005] The roll shafts 2 and 2 'are arranged above the position of the center of gravity of the accelerometer 1. Therefore, the accelerometer 1 can perform a pendulum motion around the center axis of the roll axes 2, 2 '. A damper 5 for damping the pendulum motion of the accelerometer 1 is provided on one of the roll shafts 2 and 2 '.

[0006] The heaving motion detecting device is designed to absorb the roll motion (rolling) of the ship so that the roll shaft 2,
2 'is positioned so that it is located along the roll axis of the vessel. Therefore, even if the vessel rolls, the accelerometer 1 always keeps a posture in a predetermined direction so that its input axis is oriented vertically by its own weight.

The output signal of the accelerometer 1 is supplied via a cable 7 to a control device (not shown). The vertical acceleration output from the accelerometer 1 is integrated by the integrating device of the control device to obtain the vertical velocity and displacement. In this integrator, a high-pass filter is used to remove low-frequency drift components contained in the output signal of the accelerometer 1.

Referring to FIG. 7, an example of a conventional integrator will be described. An example of this integrator is disclosed in Japanese Patent Application No. 60-241608 (Japanese Patent Publication No. 6-80406) filed on Oct. 30, 1985 by the same applicant as the present applicant.
), For details, see the same application.

This integrator comprises two integrators 61 and 62, a first low-pass filter 51 and a high-pass filter 52.
, A second low-pass filter 53 and a high-pass filter 54, and a third low-pass filter 55 and a high-pass filter 56. This integrator is obtained by improving a conventional integrator using only a high-pass filter and combining a high-pass filter with a low-pass filter.

A signal input to the integrator, for example, an acceleration signal A ₀ is integrated by first and second integrators 61 and 62, and a velocity V and a displacement P are obtained. The acceleration signal A ₀ input to the integrator is output via the first low-pass filter 51 and the high-pass filter 52.
The speed V obtained by the first integrator 61 is output via the second low-pass filter 53 and the high-pass filter 54. The displacement P obtained by the second integrator 62 is output via a third low-pass filter 55 and a high-pass filter 56.

Referring to FIG. 8, a low-pass filter and a
The function of the pass filter will be described. FIG. 8A shows the pass frequency.
Band HP (ω ≧ ω_L) With high-pass filter
FIG. 8B is a Bode diagram showing the phase characteristic and the phase characteristic.
Pass frequency band LP (ω ≦ ω _H) With low pass
FIG. 4 is a Bode diagram showing gain and phase characteristics of the filter.
FIG. 8C shows a low pass filter and a high pass filter.
Bode showing gain and phase characteristics when connected to a row
FIG.

As shown in the phase characteristic curve of FIG. 8A, when the frequency is low in the high-pass filter, the output signal is advanced in phase with respect to the input signal, and as shown in the phase characteristic curve in FIG. 8B, the frequency is low in the low-pass filter. When high, the output signal tends to lag the phase of the input signal. FIG. 8C
As shown in FIG. 7, when the low-pass filter and the high-pass filter are combined, the pass frequency band BP (ω _L ≦ ω ≦ ω _H )
Has the same function as the band-pass filter having the above, and the phase characteristics are also improved.

[0013]

The conventional heaving motion detecting device described with reference to FIG. 6 is configured to detect only the heaving (vertical motion) of the ship, that is, only the motion in one axial direction. Therefore, when the horizontal motion is relatively large, such as a ship or a floating structure anchored at a wharf or the like, it is unsuitable when it is necessary to detect the horizontal motion.

The apparatus is installed so that the roll axis of the accelerometer coincides with the roll axis of the hull. If the accelerometer does not coincide with the roll axis, the accelerometer vibrates due to the natural period of its own pendulum. Although the pendulum motion of the accelerometer is configured to be attenuated by the damper, resonance may occur when the rolling cycle of the hull approaches the natural cycle of the pendulum, and it may take time to settle.

A conventional heaving motion detection device for a ship uses a high-pass filter when integrating the detected acceleration signal. As shown in FIG. 8A, the high-pass filter has a disadvantage that a large phase difference occurs between the input and the output, and the real-time property is lost.

Although the high-pass filter and the low-pass filter can be combined to improve the phase characteristic which is a drawback of the high-pass filter, the function becomes the same as that of the band-pass filter, and the frequency band to be used is limited.

In view of the above, the present invention provides a motion detecting device capable of detecting not only one-axis motion, ie, heaving (vertical motion), but also swaying (lateral motion) and surging (forward / backward motion). The purpose is to provide.

In view of the foregoing, it is an object of the present invention to provide a motion detection device which improves the phase characteristics of a high-pass filter and, at the same time, includes an integrator having a wide range of operating frequency bands.

[0019]

According to the present invention, there is provided a motion detecting apparatus, comprising: an acceleration detecting section for detecting horizontal and vertical accelerations of an object to be measured; and an acceleration output from the acceleration detecting section. A calculation unit for calculating the horizontal and vertical velocities and displacements of the DUT by integrating,
The calculation unit includes a plurality of bandpass filters having different pass frequency bands arranged in parallel, and is configured to output a signal of one bandpass filter selected from the plurality of bandpass filters. ing.

According to the present invention, in the motion detecting device,
One of a plurality of band-pass filters that receives an output of the acceleration detection unit and detects a main frequency of the horizontal and vertical motions and receives an output of the main frequency detection unit And an output selection unit for selecting the main frequency, and the main frequency is configured to be substantially at the center of the pass frequency band of the selected band-pass filter. still,
One of multiple bandpass filters is set by a manual setting signal.
One may be configured to be selected.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a motion detecting device according to the present invention will be described with reference to FIG. The motion detection device of the present example includes the acceleration detection device 10 and three calculation units, that is, an X calculation unit 21 and a Y calculation unit.
An operation unit 22 and a Z operation unit 23 are provided. The acceleration detecting device 10 detects horizontal accelerations A _X and A _Y and a vertical acceleration _AZ of the measured object. The object to be measured may be, for example, any navigating body such as a ship, a floating dock, a floating wharf, a water floating structure such as a sea floating airfield, or any other structure that periodically moves. Good.

An X axis and a Y axis are set so as to be orthogonal to each other on a horizontal plane passing through the acceleration detecting device 10, and a Z axis is set so as to be orthogonal to both the X axis and the Y axis, that is, the vertical direction. For example, in the case of a ship, the X axis is set in the direction of the bow on the horizontal plane, and the Y axis is set on the horizontal plane so as to be orthogonal to the X axis. The horizontal acceleration A _X , A _Y and the vertical acceleration _AZ are the X-, Y-, and Z-axis components of the acceleration of the measured object when the X, Y, and Z axes are set as described above. is there.

For example, a horizontal platform having a two-axis gimbal structure is mounted on a navigation body, and an X-axis accelerometer and a Y-axis accelerometer are mounted on the horizontal platform. The horizontal platform is mounted such that the two axes of the gimbal are located along the pitch and roll axes of the hull. Also, the X-axis accelerometer is mounted so that its input axis is aligned in the roll axis direction, and the Y-axis accelerometer is mounted so that its input axis is aligned in the pitch axis direction.
At this time, the output of the X-axis accelerometer and the output of the Y-axis accelerometer are horizontal accelerations A _X and A _Y.

As an example of the acceleration detecting device 10, for example,
A strap-down type posture detecting device disclosed in Japanese Patent Application No. 3-247603 filed on Sep. 26, 1991 by the same applicant as the present applicant may be used.

The horizontal accelerations A _X and A _Y and the vertical acceleration _AZ output from the acceleration detection device 10 are supplied to three calculation units 21, 22 and 23, respectively. The three calculation units 21, 22, and 23 respectively integrate the accelerations A _X , A _Y, and A _Z to obtain the horizontal velocities V _X , V _{Y, the} vertical velocities V _Z , the horizontal displacements P _X , P _Y, and the vertical velocities. Direction displacement P
_{Find Z.}

The configuration and operation of the first example of the X operation unit 21 will be described with reference to FIGS. The Y operation unit 22
The configuration and operation of the Z operation unit 23 are the same as the configuration and operation of the X operation unit 21, and a description thereof will be omitted. As shown in FIG. 2, the X operation unit 21 includes a plurality of
Band-pass filters / integrators 211, 212, 21
3 and an output selection unit 214. Each of the three bandpass filter / integrators 211, 212, and 213 has a bandpass filter function in addition to the integrator function described above.

Referring to FIG. 3, the band pass filter functions of three band pass filter / integrators 211, 212 and 213 will be described. 3 bandpass filters /
Each of the integration units 211, 212, and 213 includes a band-pass filter having a different pass frequency band. This bandpass filter may be a combination of a highpass filter and a lowpass filter as described with reference to FIG. 8C.

Curves C1, 2C, and C3 in FIG. 3 show the gain characteristics of each bandpass filter included in the three bandpass filter / integrators 211, 212, and 213, similar to the graph on the left side of FIG. 8C. It is a Bode diagram. The pass frequency bands Ω ₁ , Ω ₂ , Ω ₃ of the _three band-pass filters are set as follows.

[0029]

[Equation 1] Ω ₁ = ω _{1L to} ω _1H Ω ₂ = ω _{2L to} ω _2H Ω ₃ = ω _{3L to} ω _3H

In the example shown in FIG. 3A, the pass frequency bands Ω ₁ , Ω ₂ and Ω ₃ of the _three band-pass filters do not overlap. Therefore, there is the following relationship.

[0031]

[Equation 2] ω _1L <ω _1H <ω _2L <ω _2H <ω _3L <ω _3L

[0032] In the example shown in FIG. 3B, the pass frequency band Omega ₁ three band-pass filters, Omega _2, 2 two pass frequency band Omega ₁ adjacent Of Omega _3, Omega ₂ and Omega _2, Omega ₃ overlaps . Therefore, there is the following relationship.

[0033]

[Equation 3] ω _1L <ω _2L ≦ ω _1H <ω _3L ≦ ω _2H <ω _3H

Each band pass filter / integrator 211,2
The outputs of the outputs 12 and 213, that is, the speed and displacement in the X-axis direction are supplied to the output selection unit 214. Output selection unit 214
Selects one of the output signals of the three band-pass filter / integrators 211, 212, and 213 according to the manually input selection signal, and outputs it. For example, when the frequency of the motion of the device under test is relatively low, the first band-pass filter / integrator 211 having the pass frequency band Ω ₁ of a relatively low frequency is selected. Conversely, when the frequency of the motion of the device under test is relatively large, the third bandpass filter / integrator 213 having the relatively high frequency pass frequency band Ω ₃ is selected.

Preferably, the main frequency ω _M of the movement of the device under test is equal to the frequency band Ω of the selected bandpass filter.
_{One of} the bandpass filter / integrators 211, 212, 213 is selected so as to be near the center frequencies of ₁ , Ω ₂ , and Ω ₃ .

Thus, according to the present embodiment, three band-pass filters / integrators 2 corresponding to the frequency of the movement of the object to be measured.
Since one of the outputs 11, 212, and 213 is selected, therefore, it has the same function as selecting and using any of the three band-pass filters.

A description will be given with reference to FIG. FIG. 4 shows three band-pass filters / integrators 211 and 2 corresponding to FIG.
FIG. 13 is a Bode diagram showing the phase characteristics of each bandpass filter included in Nos. 12 and 213. The curves D1, D2, D3 are:
These are the phase characteristics of three bandpass filters, respectively.
Different from each other. However, as described above, one of the outputs of the three band-pass filter / integrators 211, 212, and 213 is selected and output, so that the X operation unit 21 has three mutually different phase characteristics. It has the same function as selecting and using any of the bandpass filters.

FIG. 5 shows a second example of the X operation unit 21 according to the present invention. The X operation unit 21 of this example is different from the first example shown in FIG. 2 in that the integrator 215 and the main frequency detection unit 216
And the other points are the same. Integrator 2
15 X-axis direction of displacement by integrating the horizontal acceleration A _X of the X-axis direction outputted from the acceleration detection unit 10, i.e., to generate a signal representative of the motion of the X-axis direction. Main frequency detector 216
It processes the signals representing the X-axis direction movement that is output from the integrator 215, detecting the main period components contained in the signal and its frequency omega _M.

The main periodic component is a main component or a basic component of the movement of the object to be measured in the X-axis direction, and is obtained by removing noise and sudden movement from the periodic movement caused by a wave or the like.

The main frequency detector 216 may be, for example, a fast Fourier transformer (FFT analyzer), a PLL (phase locked loop), or the like. Thus, the signal for instructing the main frequency omega _M output from the main frequency detector 216, the output selection section 214 is output as a selection signal.

The output selection unit 214 based on the signal indicating the principal frequency omega _M, selects one of the three band-pass filter / integrator 211, 212, 213. Also in this case, as described above, the band pass is set so that the main frequency ω _M of the motion of the DUT is close to the center frequencies of the pass frequency bands Ω ₁ , Ω ₂ , and Ω ₃ of the selected band pass filter. Filter / integrator 211, 212, 213-1
One is selected.

For example, the center frequencies of the pass frequency bands Ω ₁ , Ω ₂ , and Ω ₃ of the _three band-pass filters are respectively denoted by ω
_{C1, ω C1,} and ω _C1. Principal frequency ω of motion of DUT
_M three center frequency omega _C1, omega _C1, among the omega _C1, to determine closest to which the center frequency, the closest center frequency omega _C1 to the main frequency omega _M of motion of an object to be measured, omega _C1, omega Bandpass filters / integrators 211, 212, 212321, and 213 of pass frequency bands Ω ₁ , Ω ₂ , and Ω ₃ having _C1 may be selected.

Although the embodiments of the present invention have been described in detail, it will be apparent to those skilled in the art that the present invention is not limited to the above-described embodiments and can adopt various other configurations without departing from the gist of the present invention. It will be easily understood.

[0044]

According to the motion detecting apparatus of the present invention, there is an advantage that not only the heaving of the measured object but also the swaying and surging can be detected.

According to the motion detecting apparatus of the present invention, the output of the band-pass filter / integrator having the band-pass filters having different pass frequency bands can be selected, so that the band-pass filter having an extremely wide pass frequency band can be selected. There is an advantage that a function similar to that provided can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a motion detection device of the present invention.

FIG. 2 is a diagram illustrating a configuration example of an X, Y, and Z calculation unit of the motion detection device of the present invention.

FIG. 3 is a diagram illustrating gain characteristics of a band-pass filter of each operation unit of the motion detection device according to the present invention.

FIG. 4 is a diagram illustrating phase characteristics of a band-pass filter of each operation unit of the motion detection device according to the present invention.

FIG. 5 is a diagram illustrating a configuration example of a second example of the X, Y, and Z calculation units of the motion detection device of the present invention.

FIG. 6 is a diagram illustrating a configuration example of a conventional heaving motion detection device.

FIG. 7 is an explanatory diagram for describing a configuration example of a conventional integration device.

FIG. 8 is an explanatory diagram for explaining gain characteristics and phase characteristics of a band-pass filter and a low-pass filter of a conventional integrator.

[Explanation of symbols]

 10 Acceleration detector 21, 22, 23 Arithmetic unit 211, 212, 213 Bandpass filter / integrator 214 Output selector 215 Integrator 216 Main frequency detector

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01H 3/00 G01H 3/00 C G01P 7/00 G01P 7/00 (72) Inventor Yasuo Takada 2-chome Minami Kamata, Ota-ku, Tokyo No. 16-46 Inside Tokimec Co., Ltd.

Claims (3)

[Claims] An acceleration detecting unit for detecting horizontal and vertical accelerations of the device under test; integrating an acceleration output from the acceleration detecting unit to calculate an acceleration in the horizontal and vertical directions of the device under test. A computing unit for computing velocity and displacement, the computing unit includes a plurality of band-pass filters having different pass frequency bands arranged in parallel,
A motion detection device configured to output a signal of one band-pass filter selected from the plurality of band-pass filters. 2. The motion detection device according to claim 1, wherein a main frequency detection unit for receiving an output of the acceleration detection unit and detecting a main frequency of the horizontal and vertical motions, and the main frequency. An output selection unit that receives an output from the detection unit and selects one of the plurality of bandpass filters, wherein the main frequency is substantially at the center of a pass frequency band of the selected bandpass filter. A motion detection device characterized by being configured as described above. 3. The motion detection device according to claim 1, wherein one of the plurality of bandpass filters is selected by a manual setting signal.