JPH0156033B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improvement of a blade angle control device for a marine variable pitch propeller.

Conventionally, marine variable pitch propellers (hereinafter referred to as
A device that automatically controls the propeller blade angle to maintain the engine load at a certain set value is the so-called automatic load control device (hereinafter referred to as "CPP").
(referred to as "ALC"), an example of which is shown in Figure 1. In this example, by operating the control handle 1, a signal S1 is input to the propeller blade angle setting device 2, engine rack setting device 3, and engine speed setting device 4, and each setting device receives the setting blade angle signal S2, the setting rack, respectively. A signal S3 and a set rotation speed signal S4 are output. The rack signal is a fuel supply signal that adjusts the fuel supply amount by the rack, so it is abbreviated as the rack signal.

On the other hand, the speed governor 6 receives the deviation signal from the adder/subtractor 6-1 and the adder/subtractor 6-1, which calculates the deviation between the actual rotation speed signal S5 from the engine rotation system 5 and the set rotation speed signal S4. It has a proportional-integral (PI) controller 6-2 that outputs a signal S6, and waits for the action to adjust the amount of slack so that the engine speed is maintained at a set value.

The actual rack signal S6 from the speed governor 6 and the set rack signal S3 are sent to an adder/subtractor 7- of the blade angle correction device 7.
1, and a blade angle correction signal S7 corresponding to the difference between the two is outputted by the PI controller 7-2 of the blade angle correction device 7 as well. This wing angle correction signal S
7 and the above set blade angle signal S2 is added/subtracted by the adder/subtractor 8.
is calculated and becomes the corrected blade angle signal S8.
The signal is sent to the CPP9, where a blade angle adjustment operation (hereinafter referred to as "change") is performed. In this way, in the conventional ALC described above, the propeller blade angle is set in advance around the target value by the blade angle setting device 2, and the blade angle is corrected by feedback control based on the actual rotation speed of the engine rotation system 5. The format is to reset to the final target value. However, since the CPP 9 normally has the slowest response speed (change speed) among the components of the ALC control system, the responsiveness of the entire ALC control system is limited by the change speed of the CPP.

Therefore, when subject to periodic load fluctuations caused by waves, etc., if the deviation between the initial setting value and the target value is large and the fluctuations are rapid, the CPP's shifting speed cannot follow it, and ALC does not function effectively. Sometimes.

The present invention aims to improve this point by focusing on the correlation observed between changes in ship rocking motion and load fluctuations, and detecting changes in ship rocking motion to predict load fluctuations in advance. By doing this, we can provide a more appropriate initial setting value for the propeller blade angle and reduce the deviation between the initial setting value and the target value.
The purpose is to expand the effective range of ALC.

To explain the principle of the present invention using diagrams, Fig. 2 is a diagram showing the state of motion of the ship, where a is the vertical acceleration A at the stern, and c is the external force (torque) applied to the propeller, that is, the load Q applied to the engine. , b is the engine speed N
This is an example of the correlation that can be recognized between these. When a ship sails in waves and the engine rack and propeller blade angle are kept constant, the acceleration A at the stern and the engine speed N are as shown in Figures a and b with respect to time t.
In this case, the torque Q received by the propeller changes as shown in c in the figure.

The reason why there is such a correlation between the acceleration at the stern and the torque received by the propeller is that the torque received by the propeller is determined by the propeller rotation speed, blade angle, and the speed of water flowing into the propeller, as shown in Figure 3. As shown in (a) and (b), the water inflow velocity V changes periodically according to the rocking of the ship. That is, when the stern, where the propeller is installed, is near the crest of a wave, the inflow speed is minimum, and when it is near the trough of the wave, the speed is maximum.

The present invention is represented in the system diagram illustrated in FIG. In contrast to the conventional ALC shown in Fig. 1, an accelerometer 10 installed on the hull to detect the rocking of the hull receives an acceleration signal S10 from the accelerometer 10, predicts the load fluctuation after the present moment, and adjusts the propeller blade angle accordingly. A blade angle correction signal generator 1 outputting a correction signal S11 of
1 is added.

As shown in FIG. 5, the blade angle correction device 11 has an analog-to-digital converter 11-1, a digital arithmetic unit 11-2, a memory 11-3, and a digital-to-analog converter 11-4. The acceleration signal S10 is converted into a digital signal by an analog-digital converter 11-1, and then
The input time and the acceleration data are sequentially stored in the storage unit 11-3 via the digital arithmetic unit 11-2. These acceleration data accumulated after a certain period of time are taken out to the digital calculator 11-2 and analyzed to calculate the period, amplitude, and phase of the acceleration fluctuation. By knowing these quantities, load fluctuations from that point onwards can be predicted. On the other hand, according to a predetermined calculation procedure for these various quantities, a blade angle correction amount that minimizes the predicted load fluctuation is calculated, and the blade angle correction amount is calculated to minimize the predicted load fluctuation. is converted into a wing angle correction signal S11 and output.

With this configuration, the set blade angle signal S2 is corrected by the correction signal S11 in the adder/subtractor 8 to a more appropriate value, that is, a value closer to the target value. The deviation remaining between this corrected setting signal and the target value is also simultaneously sent to the adder/subtractor 8 as a blade angle correction signal S by feedback control based on the rotation speed of the engine rotation system 5, as in the conventional ALC.
7, and the last modified signal S8' is CPP
Sent to 9th. FIG. 6 is a system diagram showing another embodiment.

While conventional ALC is limited to feedback control that controls the propeller blade angle from changes in engine speed that occur as a result of load fluctuations, the present invention enables changes in external forces that cause load fluctuations to be detected in advance from ship motion. Since it incorporates so-called feed forward control, which predicts load fluctuations in advance by detecting them and uses them for blade angle control, the blade angle control of the variable pitch propeller can quickly follow the changes, making ALC effective. The range can be expanded.

[Brief explanation of drawings]

Figure 1 is a system diagram of a conventional blade angle control device.
Fig. 2 is a motion diagram of the ship, Fig. 3 A and B are side views showing the state of the ship, Fig. 4 is a system diagram showing an embodiment of the present invention, Fig. 5 is a partial system diagram of the same, and Fig. 6 is a system diagram showing another embodiment. 1... Control handle, 2... Blade angle setting device, 3... Rack setting device, 4... Rotation speed setting device, 5... Engine rotation system,
6... Speed governor, 7... Blade angle correction device, 6-1, 7-1
...adder/subtractor, 6-2, 7-2...PI controller,
8... Adder/subtractor as a calculation unit for corrected blade angle, 9... Variable pitch propeller, 10... Accelerometer, 11... Blade angle correction correction signal generator.

Claims (1)

[Claims] 1 Equipped with a blade angle setting device that outputs a set propeller blade angle signal in response to a signal from the control handle, a rack setting device that outputs a setting easy signal for the engine, and a rotation speed setting device that outputs a set engine speed signal. death,
The blade angle correction device is provided with a blade angle correction device that outputs a blade angle correction signal based on the actual speed or actual rotational speed of the engine and the set signal for these, and calculates the deviation between the blade angle correction signal and the set blade angle signal to correct the blade angle. A wing angle control device having a computing unit that computes the angle includes an accelerometer that detects the rocking motion of the ship, and a signal generator that outputs a wing angle correction signal according to the signal of the accelerometer. A blade angle control device for a variable pitch propeller, characterized in that the blade angle correction signal is additionally calculated in a variable pitch propeller.