JPS63172037A - Method for controlling positive oscillation isolating supporter - Google Patents

Abstract

PURPOSE:To save power required for controlling the supporter in the caption, by detecting any force applied to a drive rod and feeding back only the extremely low frequency component of the force so that control for inhibiting generation of this force may be achieved. CONSTITUTION:A positive oscillation isolating device 1 is mounted on a hull stand 3 and a force sensor 37 is installed on a drive rod 16. Any signal detected by the sensor 37 is amplified through an amplifier 38 and fed in a low pass filter 39. Here, any oscillation caused by the swell of a wave or the like is filtrated so that high frequencies caused by the oscillation of a diesel engine 3 are removed from the detected signal. Then low frequency signals are fed in a subtracter circuit 40 to subtract those low frequency signals and fed in an adder/subtracter circuit 41. On the other hand, any signal detected by a residual oscillation detector 31 is input into a control unit 34 where a control signal for nullifying the residual oscillation is operated and the result of operation is fed in the adder/subtractor circuit 41 where the result is overlapped on the abovementioned low frequency signal to be fed in a surbo-valve. Therefore, no drive force can be generated by low frequency oscillation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an active vibration isolation control method for vibration isolation by oscillating vibrations that cancel out vibrations propagating from a vibrating body.

[Prior art]

Conventionally, elastic support using springs, rubber, etc. has been used to prevent vibrations from a vibration source from propagating to the surroundings. However, these vibration isolation means using elastic bodies have a vibration resistance of 5 to 500
It is difficult to significantly dampen low- and medium-wave vibrations on the order of Hz, and in recent years, active vibration damping devices have been developed that produce vibrations that cancel out the propagating vibrations.

In this active vibration isolator, if the vibration source is supported only by the vibration isolating vibration generating means, it will not be possible to support the vibrating body in the event of a failure of the vibration isolator, so a device in combination with a rubber elastic body was developed. has been done.

A conventional active vibration isolator combined with this rubber elastic body will be explained below with reference to the attached FIGS. 2 to 4.

In the figure, the active vibration isolator 11 is attached to the diesel engine 2 at four corners of the section 5 (only two corners are shown in the figure).
and the hull mount 3, and the engine is mounted in a hollow part in the center with an intermediate drive plate 8 between the upper plate 6 attached to the part 5 and the lower plate 7 on the side of the hull mount 3. It has a structure in which cylindrical rubber elastic bodies 9 and 10 are provided.

The vibration isolating vibration for canceling the vibration propagated from the engine 2 to the installation base 3 is achieved by fixing the tip of the drive rod 16 extending from the actuator 15 to the drive plate 8, and fixing the other end of the drive rod 16 to the drive plate 8. , as shown in FIG. 4, is fixed to a piston 18 fitted into a cylinder 17. Said piston 18 is controlled by a servo valve 19.

Next, the outline of the conventional control method will be explained. The fundamental frequency of vibration and noise of the diesel engine 2 corresponds to the rotational speed of the engine 2. Therefore, in the active vibration isolator 11 shown in FIG. 2, the rotational state of the engine 2 is detected by the rotation sensor 30, and the residual vibration sensor 31 sends a control signal to the rotation sensor 30 to zero the residual vibration propagated to the installation base 3. The relative position is kept constant by a detection signal from a control unit 32 that calculates a control operation for output in synchronization with the engine 2 and a displacement detector 33 that detects the relative position between the engine 2 and the installation base 3 using waves or the like. The control signal from the control unit 34 that calculates the control operation is transmitted to the active vibration isolator 11.
It provides vibration isolation by providing

By the way, in the vibration isolation control means shown in FIG. 2, the actuator operates so as to fix the relative position of the engine, which is a vibration source, with respect to the hull.

Therefore, when the hull is rocking due to wave swells, a large force is applied to the actuator, requiring a large capacity actuator. There is no practical value in doing it.

If fixed displacement control is performed for extremely low frequency vibrations of several Hz or less, such as the undulation of waves, the required power can be reduced, but such a control method has not yet been proposed. .

[Purpose of the invention]

The present invention has been made in view of the above problems, and aims to provide an effective control means for reducing the force generated by an actuator by omitting displacement control for extremely low frequency vibrations. .

[Structure of the invention]

To achieve the above object, the control method for an active vibration isolator of the present invention is a method for controlling an active vibration isolator in which an actuator generates vibrations that cancel out vibrations propagating from a vibrating body to prevent the propagation of vibrations. A force detection means for detecting the five loads applied to the drive rod of the actuator of the vibration device, a filtering means for extracting a low frequency signal from the detection signal of the nuclear force detection means, and a calculation means for calculating a control signal for active vibration isolation. and addition or subtraction means for superimposing the low frequency signal from the filtering means on the control signal given from the calculation means,
The present invention is characterized in that the control signal given from the addition or subtraction means is output to the actuator of the active vibration isolator.

As the control means for reducing the residual vibration to zero according to the present invention, conventional means can be used as is.

The force detecting means used when carrying out the present invention includes a load cell, a strain gauge, etc., but is not limited thereto.

The method of the present invention detects the force applied to the drive rod of an active vibration isolator, feeds back only the extremely low frequency component, and performs control to prevent this force from being generated, thereby reducing the vibration caused by the shaking of the ship due to waves. By eliminating the output of the actuator in response to low-frequency vibrations, the power required for the active vibration isolator is reduced.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail by way of an example with reference to the accompanying drawings.

FIG. 1 is a block diagram for explaining the configuration of a control device according to this embodiment, and shows an active vibration isolator 1 similar to that shown in FIG.
is attached to the hull frame 3, and the marine diesel engine 2 is attached to support the part 5. A force sensor 37 made of a strain gauge is attached to the drive rod 16 and is configured to detect the force applied to the drive rod 16. The force sensor 37 may be constructed by interposing a load cell between the drive rod 16 and the drive plate 8 instead of the strain gauge. Other members are given the same numbers as the same members as in FIGS. 2 and 3, and explanations thereof will be omitted.

The detection signal of the force sensor 37 is amplified by an amplifier 38 and given to a low-pass filter 39 .

In this embodiment, vibrations caused mainly by wave swells are filtered, and high frequencies caused by vibrations of the diesel engine 2 are removed from the detection signal. Then, this low frequency signal is applied to a subtraction circuit 40, this low frequency signal is subtracted from the signal A corresponding to the load when the active vibration isolator 1 is in a stationary state, and the result is applied to an addition circuit 41.

However, if the detection signal of the force sensor 37 is negative with respect to the positive output of the adding circuit 41, it is an adding circuit;
In the opposite case, the addition circuit 41 is replaced with a subtraction circuit.

On the other hand, the detection signal given from the residual vibration detector 31 consisting of a load cell is input to the control unit 34 in synchronization with the detection signal from the rotation encoder 30 provided on the output shaft of the diesel engine 2, as in the conventional technology. A control signal is calculated to make the residual vibration zero, and the result of the calculation is applied to the addition or subtraction circuit 31, superimposed on the low frequency signal, and applied to the servo valve 19 in FIG. 4.

Since the active vibration isolator 1 of this embodiment is given the control signal as described above, the direction in which the servo pulp 19 releases the force applied to the drive rod 16 due to vibrations caused by wave swells, etc. Therefore, it does not output driving force in response to low frequency vibrations. Also, diesel engine 2
For vibrations of about 5 to 500 Hz, control is performed to reduce residual vibrations to zero. Furthermore, since the active vibration isolator 1 used in this embodiment does not function against high frequency bones of 500 Hz or higher, the vibration isolating performance matches that of the rubber elastic bodies 7 and 8.

〔Effect of the invention〕

As explained above, the control method for the active vibration isolator of the present invention is configured to reduce the force applied to the actuator of the slowly vibrating extremely low frequency vibration component to zero, which is necessary to operate the active vibration isolator. It is possible to reduce the amount of power required for the engine, and it is possible to effectively and economically carry out marine engine active vibration isolation.

[Brief explanation of the drawing]

Fig. 1 is a block diagram for explaining a control method according to one embodiment, Fig. 2 is a conventional active vibration isolator using a rubber elastic body, and Fig. 3 is a vibration isolating support part of the device shown in Fig. 2. Configuration diagram,
FIG. 4 is a block diagram of the actuator of the device shown in FIG. 3. 1... Active vibration isolator, 2... Diesel engine,
3... Hull mount, 5... Engine mounting part, 15...
・Actuator, 16... Drive rod, 30...
Rotation sensor, 34... Control calculation means, 37... Force sensor, 39... Low pass filter (filtering means), 41
...Addition or subtraction means.

Claims (1)

[Claims] An active vibration isolator that prevents the propagation of vibration by generating vibrations using an actuator to cancel vibrations propagating from a vibrating body, comprising: a force detection means for detecting a load applied to a drive rod of an actuator of the active vibration isolator; a filtering means for extracting a low frequency signal from the detection signal of the detection means; a calculating means for calculating a control signal for active vibration isolation; and an addition for superimposing the low frequency signal from the filtering means on the control signal given from the calculating means. or subtraction means, and outputting a control signal given from the addition or subtraction means to an actuator of the active vibration isolator.