JPH0680406B2 - Integrator - Google Patents

Description

TECHNICAL FIELD The present invention relates to an integrating device, for example, an integrating device suitable for double integration that further integrates an integrated value of a target quantity. Is.

[Conventional technology]

As a case where the integration value of the target amount is further integrated, for example, acceleration may be integrated to obtain a velocity, and further velocity may be integrated to obtain a displacement amount.

An example of such a double integrator is shown in FIG. In the block diagram of Fig. 2, the high-pass filter is connected to the terminal Q1 to which the acceleration is input from the outside.
10 is connected to the high-pass filter 10 and integrators 12 and 14 are connected in series.

Of these, the high-pass filter 10 has a time constant TA, for example.
As opposed to Has a transfer function G1 represented by, and its Bode plot is as shown in FIG. 3, for example. In the above formula (1), S is a complex number in the Laplace transform,
The figure (A) shows a gain, and the figure (B) shows a phase. The same applies to FIGS. 4 to 9.

The integrators 12 and 14 are, for example, for the time constant TB, Has a transfer function G2 represented by, and their Bode plots are as shown in FIG. 4, for example.

Therefore, the characteristics of the entire double integrator shown in FIG.
As shown in the figure.

By the way, generally, in an integrating device, a drift due to a low frequency component becomes a problem. Therefore, as shown in FIG. 2, the high-pass filter 10 is added before the input of the integrator 12.

[Problems to be solved by the invention]

However, in the conventional device as described above, the integration constant is extremely long, especially for low-frequency acceleration input, so that there is a disadvantage that a long settling time is required. Further, although it follows a steady input, if a sudden change occurs, a drift occurs and a new long settling time is required, which makes the operation unstable.

In addition, as shown in FIG. 5, in the integration region of the gain of −20 dB / dec, there is a disadvantage that a phase difference occurs as shown in FIG.

The present invention has been made in view of the above points, and an object of the present invention is to provide an integrating device that has a reduced drift time, a short settling time, and operates stably.

[Means for solving problems]

In order to solve the above problems, the integrator of the present invention includes at least two integrators connected in cascade.
Filter means for reducing a low frequency component of a signal having a time constant larger than that of the integrator, and correction means for performing phase correction having a time constant smaller than that of the integrator, They are each connected to an integrator.

[Action]

According to the present invention, the low-frequency signal component that causes the drift is reduced and removed by the filter means, and the correction means also corrects the phase.

〔Example〕

Hereinafter, an integrator according to the present invention will be described in detail based on an embodiment shown in the accompanying drawings.

FIG. 1 shows an embodiment of the present invention. In this block diagram, a low-pass filter 16 and a high-pass filter 18 are connected to a terminal Q to which an acceleration signal is input from the outside.
Are connected in series. The output of the high pass filter 18 is output as an acceleration signal.

The high-pass filter 18 is connected to the first integrating circuit 20, and the output of the first integrating circuit 20 is output as a speed signal. The first integrator circuit 20 has a configuration in which a low-pass filter 22, an integrator 24, and a high-pass filter 26 are connected in series.

The first integrator circuit 20 is connected to the second integrator circuit 30,
The output of the second integration circuit 30 is output as a displacement signal. The second integrating circuit 30 has a configuration in which a low-pass filter 32, an integrator 34, and a high-pass filter 36 are connected in series.

Of these, the Lowpass Filter 16 is The transfer function G of the primary delay element type with the time constant TL1 represented by
It has A, and removes instantaneous noise. Highpass Filter 18 The transfer function G of the quadratic delay element type with the time constant TL1 represented by
It has B and removes low frequency noise and drift.

Next, the low-pass filters 22 and 32 included in the integrating circuits 20 and 30 are included.
The transfer function GC of is The Bode diagram of the entire low-pass filters 22 and 32 is shown in FIG. 6, for example.

The transfer function GE of the high pass filter 26, 36 is The board diagram of the entire high pass filter 26, 36 is shown in FIG. 7, for example. The transfer function
It is well known that the Bode plot changes depending on the value of GE because it is a quadratic lag element type.

The transfer function GD of the integrators 24 and 26 is The Bode diagram of the whole integrator 24, 26 is shown in FIG. 8, for example. When the graphs of FIGS. 6 to 8 are added together, a Bode diagram showing the overall characteristics of the integrating circuits 20 and 30 is shown, which is shown in FIG. The time constant TL2 of the low-pass filters 22 and 32 is set smaller than the time constant TI of the integrators 24 and 34, and the time constant TH2 of the high-pass filters 26 and 36 is set larger than the time constant TI of the integrators 24 and 34. To do. In addition, the time constant T of the low-pass filters 22 and 32
L2 is the phase advance by the high-pass filters 26, 36 (7th
(See FIG. 6B) is set. Integrator circuit
The characteristics of 20, 30 are determined so that the integral characteristic, that is, the gain has a slope of -20 dB / dec in a constant region with respect to the frequency determined by the time constant TI of the integrators 24, 34.
(See FIG. 9 (A)).

Next, the operation of the above embodiment will be described. First, the high-pass filters 26 and 36 that remove low-frequency components are integrated circuits 2
Since they are provided for 0 and 30, respectively, the low frequency component is satisfactorily reduced as shown in FIG. 9 (A). Therefore, the drift is suppressed, and the operation becomes stable even if the double integration is performed.

Also, as shown in FIG. 9 (B), the low-pass filter 2
By providing 2,32, the phase characteristics by the integrators 24,34 and the high-pass filters 26,36 are improved, and there is no phase shift in the integration region as shown by the double-dashed line arrow in the figure. Parts will be included.

Although the first and second integrating circuits 20 and 30 are provided with the low-pass filters 22 and 32 in the first stage and the high-pass filters 26 and 36 are provided in the latter stage in the above embodiment, the present invention is not limited to this. However, the order may be arbitrary. For example, the low-pass filters 22 and 32 may be the latter stage, and the high-pass filters 26 and 36 may be the first stage. Further, when the secondary pass element type is used as the high pass filters 26, 36, it is preferable to set the damping coefficient ζ to about 0.5 to 1. The high-pass filters 26, 36 may have a first-order lag element type transfer function.

A suitable application example of the integrating device according to the present invention is detection of vertical movement (heaving) of a ship. That is, a horizontal stabilizer is provided in the ship, an accelerometer is placed on the horizontal stabilizer to detect vertical acceleration, and double integration is performed from this acceleration to detect the vertical position.

〔The invention's effect〕

As described above, according to the integrating device of the present invention,
The drift is reduced, the settling time is shortened, and the operation is stabilized. Also, the problem of phase shift in the integration region is solved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an integrating device according to the present invention, FIG. 2 is a block diagram showing an example of a conventional device, and FIGS. 3 to 5 are views of respective parts in the conventional device shown in FIG. Bode diagrams showing characteristics, and FIGS. 6 to 9 are Bode diagrams showing characteristics of each portion in the embodiment of FIG. 20,30 ... Integrator, 22,32 ... Low pass filter, 24,34 ...
Integrator, 26,36 ... High-pass filter.

Claims (2)

[Claims] 1. An integrator comprising at least two integrators connected in cascade, the filter means having a time constant larger than that of the integrator and reducing low frequency components of a signal, and the integrator of the integrator. An integrator having a time constant smaller than the time constant and correction means for performing phase correction, each being connected to the integrator. 2. The integrating device according to claim 1, wherein the filter means is a high-pass filter, and the correcting means is a low-pass filter.