JPH0619302B2 - Collecting cylinder pressure control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a collecting cylinder pressure control device for a blow-out type wind tunnel, and particularly has a mechanism for controlling the Mach number of the air flow (hereinafter referred to as a Mach number control device). The present invention relates to a collecting cylinder pressure control device for a blow-out type wind tunnel.

[Conventional technology]

As shown in FIG. 3, the blow-out type wind tunnel guides the compressed air accumulated in the storage tank 1 through the high-pressure conduit 2, and reduces the pressure to a constant pressure by the pressure regulating valve 3 whose valve opening can be adjusted by a signal from the outside. After that, it has a schematic configuration of discharging to the atmosphere via a collecting cylinder (also called a rectifying cylinder) 4, a nozzle 5, and a measuring unit 6 that regulates the flow of the air flow. Aerodynamic measurements can be performed.

As described above, in the blow-out wind tunnel, ventilation is performed only by releasing the compressed air accumulated in the storage tank 1, and therefore the ventilation time is limited to an extremely short time (usually several seconds to several tens of seconds). During this time, the measurement must be completed.
Further, if the compressed air inside the storage tank 1 is discharged by ventilation, it takes a long time (typically several hours) to refill the storage tank 1 with the compressed air. Therefore, in the control device of the blow-out type wind tunnel, not only the accuracy for guaranteeing the reproducibility of the experiment but also the high-speed responsiveness of controlling the air flow inside the wind tunnel to a desired state within a short time is required.

FIG. 4 is a configuration block diagram of a conventional collecting cylinder pressure control device for a blow-out type wind tunnel. This device opens the pressure regulating valve 3 so that the total pressure (stagnation point pressure) of the collecting cylinder 4 becomes a predetermined value. It has a function of adjusting the degree.

In FIG. 4, a collecting cylinder pressure control device 10 takes a difference between a collecting cylinder pressure setting device 11 for setting the pressure in the collecting cylinder and an output of the collecting cylinder pressure setting device 11 and a collecting sinus pressure described later. A subtracter 12, a feedback control unit 13 that performs proportional and integral calculations on the output of the subtractor 12, and a gain converter 14 that adjusts the gain of the output of the feedback control unit 13 according to the pressure of the storage tank. I have it.

Such a conventional collecting cylinder pressure control device inputs the pressure signal in the collecting cylinder 4 detected by the collecting cylinder pressure transmitter 7, and deviates from the collecting cylinder pressure setting signal output from the collecting cylinder pressure setter 11. Is calculated by the subtracter 12, and the feedback controller 13 performs proportional and integral calculations on this deviation. The gain converter 1 performs gain conversion according to the pressure signal in the storage tank 1 output from the storage tank pressure transmitter 8 with respect to the feedback control signal output from the feedback control unit 13.
4 and outputs it to the pressure regulating valve 3 as a pressure regulating valve opening signal so that the stagnation pressure of the collecting cylinder 4 becomes a predetermined pressure.

In such a conventional device, the parameters of the pressure transfer characteristic of the collecting cylinder during the startup process and ventilation experiment during the test and verification of the pressure control system, the gain constant of the proportional integrator, and the parameter calculation of the integration constant were calculated.・ Setting work etc. depends on the manual work of the designer, and there is a drawback that workability and operability are poor.

In order to solve this, in the past, Japanese Patent Laid-Open No. 61-13830
4 has been proposed, and a method is disclosed in which the pressure transfer characteristic of the collecting cylinder of the wind tunnel is measured during ventilation and the integration time is determined online based on the measurement result. Thus, the parameter determination of the pressure conduction characteristic of the collecting cylinder and the calculation and setting of the gain constant and the integration constant of the comparative integrator are automatically performed.

Further, in the blow-out type wind tunnel, conventionally, it is sufficient if the collecting cylinder pressure control device can maintain the collecting cylinder pressure at a constant value under the condition that the Mach number is constant, that is, the air volume of the measuring unit is constant. It is considered that it is extremely rare to change the collecting cylinder pressure and Mach number during one ventilation due to the difficulty of control.

On the other hand, with the rapid progress of aircraft in recent years and the improvement of wind tunnel measurement technology using computers, the transient response was measured by changing the Mach number and the stagnation pressure of the collecting cylinder in the middle of one ventilation. Or, it has been desired to obtain more advanced data.

Generally, the pressure response of the collecting cylinder shows a characteristic of almost first-order lag, but when the Mach number is changed in this way, its time constant T must change according to the Mach number as shown in the graph of FIG. Has been found by the inventors' research as described later. Therefore, the time constant in the vicinity of Mach number M = 1,0 becomes the smallest and the response becomes the fastest, and becomes large at other values.

That is, if the integration time is adjusted to the optimum value when M = 1.0, the integration time is too small except for M = 1.0, and the pressure response becomes unstable.

[Problems to be Solved by the Invention]

The method according to the above-mentioned document has a problem that the configuration is complicated and that the optimum integration time cannot be known unless ventilation is actually performed.

The present invention is made in order to eliminate the drawbacks of the conventional collecting cylinder pressure control device by the feedback control, and simplifies the operation at the time of changing the Mach number setting value and the collecting cylinder pressure setting value, and An object of the present invention is to provide a collecting cylinder pressure control device capable of obtaining an appropriate control gain during ventilation.

[Means for Solving the Problems]

According to the present invention, the Mach number setting device for instructing the Mach number of the air flow, and the air flow by the compressed air stored in the air storage tank based on the Mach number setting signal output from the Mach number setting device With a control mechanism that controls by the opening degree,
In a collecting cylinder pressure control device for controlling the pressure in the collecting tunnel of a blowout type wind tunnel, a stagnation point of the collecting cylinder and a stagnation point of the collecting cylinder for outputting a collecting cylinder pressure setting signal for instructing a pressure set value. A collecting cylinder pressure transmitter that outputs a pressure detection value as a collecting cylinder pressure signal, and an integration time calculating unit that receives a Mach number setting signal output from a Mach number setting unit and calculates an optimum integration time according to the Mach number. , Receives the integration time setting signal output from the integration time calculation unit, and outputs the collection cylinder pressure setting signal output from the collection cylinder pressure setter and the collection cylinder pressure transmitter at the integration time corresponding to this signal. Feedback control that performs proportional and integral control calculation on the collecting cylinder pressure signal and calculates and outputs a feedback control signal for controlling the stagnation point pressure of the collecting cylinder to the value set by the collecting cylinder pressure setter. It is characterized by comprising and.

[Work]

The optimum integration time is determined based on the relationship between the known Mach number setting signal and the integration time from the Mach number setting signal by the Mach number setting device, and the integration operation in the feedback control unit is performed according to this value. That is, when the object to be controlled can be regarded as a first-order lag like the collecting cylinder pressure, the optimum control force is performed by making the integration time proportional to the time constant of the first-order lag of the control object.

Therefore, even when the Mach number of the collecting cylinder is changed, the operation can be simplified and optimum gain compensation can be obtained. Further, the set value of the proportional gain can be grasped before ventilation.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, in which the collecting cylinder pressure control device 20 sets a target value of the collecting cylinder pressure similarly to the conventional device and shows the setting value. A collecting cylinder pressure setter 21 that outputs a pressure setting signal, and a feedback control unit 23 that performs proportional and integral calculations on the output of the collecting cylinder pressure setter 21 and the stagnation pressure of the collecting cylinder to be described later, and outputs it as a feedback control signal. A gain converter 24 that adjusts the output gain of the feedback control unit 23 by the output Pt converted into an electric signal by the air storage tank pressure transmitter 8 that detects the pressure of the air storage tank 1 is provided.

On the other hand, the Mach number setting device 30 is provided outside the collecting cylinder pressure control device 20.
Is provided, and the Mach number setting signal Ms output from this is input to the integration time calculator 25 provided in the collecting cylinder pressure control device 20, and as will be described later, in this integration time calculator 25, there is The integration time is calculated according to the known relational expression of the stored Mach number and the integration time. Then, the feedback control unit 23 performs an operation according to the integration time T _i which is the calculation result.

Here, the time constant of the pressure response of the collecting cylinder described above is Mach number M.
It has been found by the research of the inventor that the relation changed by

Here, k is the specific heat ratio of air, that is, the ratio of the low pressure specific heat and the quantitative specific heat, and is usually k = 1.4.

Therefore, the integration time may be obtained using this relationship, and the integration time T _i is Can be calculated by Here, A is a constant determined by the wind tunnel, M _s is a set value given by the Mach number setting device 20, and k is a specific heat ratio of air.

Here, the Mach number setting signal is used instead of the Mach number setting signal used in the equation (1) because the Mach number setting signal is more stable than the Mach number setting signal.

The equation (2) is stored in the memory in the integration time calculator 25.

With such a control device, no matter how the Mach number is changed, an optimum response can be obtained, and it is not necessary to individually set the integration time. In addition, since the basic arithmetic expression is clear as described above, the optimum set value can be known in advance and stable operation can be performed without ventilation.

The collecting cylinder pressure control device according to the present invention can be configured by combining analog electronic circuits, and a part or all thereof can be realized by an electronic computer.

In the above embodiment, the differential fluid is air, but the present invention can obtain the same effect even when a gas other than air, such as nitrogen or helium, is used.

〔The invention's effect〕

As described above, according to the present invention, since the integration time of the feedback control device is changed according to the setting of the Mach number, a stable response is always possible and a stable collecting cylinder pressure can be obtained. .

In addition, since the integration time value can be angled before ventilation, drivability is improved and stable operation can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the collecting cylinder pressure control device according to the present invention, FIG. 2 is a graph showing the relationship between the Mach number M and the time constant T of the pressure response, and FIG. FIG. 4 is a block diagram of a conventional collecting cylinder pressure control device showing a typical blow-out type wind tunnel. 1 ... Storage tank, 2 ... High-pressure conduit, 3 ... Pressure regulating valve, 4 ...
Collecting cylinder, 7 ... Collecting cylinder pressure transmitter, 8 ... Storage tank pressure transmitter, 20 ... Collecting cylinder pressure control device, 21 ... Collecting cylinder pressure setting device, 23 ... Feedback control unit, 24 ... Gain converter, 25 ... Integral time calculation unit, 30 ... Mach number setting device.

Claims (2)

[Claims] 1. A Mach number setting device for instructing the Mach number of the air flow, and an air flow of compressed air stored in an air storage tank based on a Mach number setting signal output from the Mach number setting device to open a pressure regulating valve. In the collecting cylinder pressure control device for controlling the pressure in the collecting tunnel of the blow-out type wind tunnel, the collecting cylinder pressure setting signal for instructing the stagnation pressure setting value of the collecting cylinder is output. A cylinder pressure setting device, a collecting cylinder pressure transmitter that outputs a stagnation point pressure detection value of the collecting cylinder as a collecting cylinder pressure signal, and a Mach number setting signal output from the Mach number setting device, An integration time calculating unit for calculating an optimum integration time according to the integration time, and an integration time setting signal output from the integration time calculating unit, and an integration time output from the collecting cylinder pressure setting unit at an integration time corresponding to this signal. Proportional and integral control calculation is performed on the collective cylinder pressure setting signal and the collective cylinder pressure signal output from the collective cylinder pressure transmitter to control the stagnation pressure of the collective cylinder to the value set by the collective cylinder pressure setter. And a feedback control unit for calculating and outputting a feedback control signal for controlling the collecting cylinder pressure control device. 2. The feedback control unit receives a storage tank pressure signal output from the storage tank pressure transmitter, and based on this signal, a gain conversion for calculating a proportional gain with respect to an opening command signal of the pressure regulating valve. The collecting cylinder pressure control device according to claim 1, further comprising a container.