JPH02302643A - Apparatus for controlling pressure in collecting drum - Google Patents

Abstract

PURPOSE:To simplify the changing operation of preset values and to obtain a suitable control gain by providing a collecting-drum-pressure setting device, its transmitter, an output-operation control part, a bladder pressure transmitter, and a gain converter for operating the output of the setting device. CONSTITUTION:The following parts are provided: a collecting-drum-pressure setting device 21; a feedback control part 23 for operating proportion/integration for the output from the device 21 and the pressure at a stagnating point; and a gain operating part 24 for regulating the output gain of the control part 23 from the output of a bladder pressure transmitter 8 for detecting the pressure in a bladder 1. The total pressure in the collecting drum 4 is transmitted to the control part 23 through a collecting-drum pressure transmitter 7. The output of the setting device 21 is also imparted into a converter 24 directly. Gain conversion is performed with the two signals from the transmitter 8 and the setting device 21 as parameters. Then, the result of the operation in the operating part 24 is sent to a regulating valve 3, and the valve opening degree is regulated. In this way, the operation can be simplified and the optimum gain compensation can be obtained even if the design values are changed and the bladder pressure is strikingly decreased at the end of ventilation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pressure transmitter for a collection shell of a blow-out type wind tunnel, and in particular a mechanism for controlling the Matsuha number of airflow (hereinafter referred to as a Matsuha number transmitter). This invention relates to a collecting shell pressure transmitter for a blow-out type wind tunnel.

[Conventional technology]

As shown in Figure 2, in the blow-out type wind tunnel, compressed air accumulated in an air storage tank 1 is guided through a high-pressure conduit 2, and the pressure is reduced to a constant pressure by a pressure regulating valve 3 whose opening degree can be adjusted by an external signal. After that, the airflow is discharged into the atmosphere via a collecting cylinder (also called f!! flow cylinder) 4, a nozzle 5, and an aFJ constant part 6, which adjusts the flow of the airflow. The desired aerodynamic measurements 71111 can be implemented.

In this way, in the blow-out type wind tunnel, ventilation is achieved only by releasing the compressed air accumulated in the air storage tank 1, so the ventilation time is limited to an extremely short period of time (usually several seconds to several tens of seconds). Total A during this time? 1 must be completed. Moreover, if the compressed air inside the air storage tank 1 is released by ventilation, it will take a long time (usually several hours) to refill the air storage tank 1 with compressed air. For this reason, a blowout type wind tunnel transmitter is required to have not only accuracy to ensure reproducibility of experiments, but also high-speed response to control the airflow inside the wind tunnel to a desired state within a short period of time.

FIG. 3 is a block diagram of a conventional blow-out type wind tunnel collecting shell pressure transmitter. This device operates by opening the pressure regulating valve 3 so that the pressure (stagnation point pressure) in the collecting shell 4 becomes a predetermined value. The function to adjust the degree is H.

In FIG. 3, a collecting barrel pressure transmitter 10 includes a collecting barrel pressure setting device 11 for setting the pressure inside the collecting barrel, and calculates the difference between the output of this collecting barrel pressure setting device 11 and the collecting cavern pressure described later. a subtracter 12, proportional to the output of this subtracter 12;
3 and a gain converter 14 that performs gain adjustment on the output of the feed/<tsk control section 13 in accordance with the air storage tank pressure. - Such a conventional collecting shell pressure transmitter inputs the pressure signal inside the collecting shell 4 detected by the collecting shell pressure transmitter 7 and outputs the collecting shell pressure setting signal from the collecting shell pressure setting device 11. The deviation is calculated by the subtractor 12, and the feedback control unit 13 performs proportional and integral calculations on this deviation. The gain converter 14 performs gain conversion according to the pressure signal in the air storage tank 1 output from the air storage tank pressure transmitter 8 in response to the feedback control 1c outputted from the feedback control unit 13. It is output to the pressure regulating valve 3 as a pressure valve opening signal so that the stagnation point pressure of the collection cylinder 3 becomes a predetermined pressure.

Various proposals have been made regarding collecting barrel pressure transmitters in the Aerospace Technology Research Institute report TR-647, Japanese Patent Application Laid-open No. 61-138304, Japanese Patent Application Laid-open No. 63-256835, and the like.

In all of these, the pressure regulating valve 3 is controlled only by the feed and droplet control section 13 as described above, but in Aerospace Technology Research Institute report TR-647 and Japanese Patent Application Laid-Open No. 63-256835, the gain The converter 14 performs a gain conversion of 1/PT (P and r indicate the pressure signal of the reservoir tank) to compensate for changes in the characteristics of the pressure regulating valve due to a decrease in the pressure of the reservoir tank. In 61-138304, the pressure transmission characteristics of the collecting shell in the wind tunnel were determined by a total of Δ-1 during ventilation.
Then, the gain and integration time are set online based on the results.

In such conventional blow-out type wind tunnels, it is thought that it is sufficient for the collecting shell pressure transmitter to be able to maintain the collecting shell pressure at a constant value under a constant Matsuha number, that is, a fixed constant of allllllll, - Collecting shell pressure during ventilation times,
It was extremely rare to change the number of pine trees due to the difficulty of control.

On the other hand, with the rapid progress of aircraft in recent years and the improvement of computer-based wind barrel needle A11l technology, the Matsuha number and collecting shell pressure were changed during the - ventilation period to obtain a total of 11111 transient responses. It has become desirable to obtain more sophisticated data.

[Problem to be solved by the invention]

However, if the conventional collecting shell pressure transmitter simply uses a proportional gain according to 1/PT, it is necessary to reset the proportional gain each time the collecting shell pressure setting value is changed. However, there is a problem that the operation becomes complicated.

In addition, the amount of air passing through the pressure regulating valve changes depending on the pressure upstream and downstream of the pressure regulating valve, but in general, the pressure in the air storage tank gradually decreases with ventilation, so the pressures on the upstream and downstream sides of the pressure regulating valve become close to each other. , the air volume decreases at the same valve opening. In other words, the flow rate gain of the pressure regulating valve will decrease, but if the gain compensation based on the air storage tank pressure is set to 1/P1, the control gain will decrease near the end of ventilation, where the air storage tank pressure will drop significantly. cannot be adequately compensated.

Furthermore, according to Japanese Patent Application Laid-Open No. 138304/1983, if the proportional gain is set based on the measurement results during ventilation, an appropriate setting can be made, but the configuration of the control device becomes complicated.
In addition to lacking reproducibility, there are problems in that the optimal proportional gain cannot be determined unless ventilation is performed.

The present invention was made in order to eliminate the drawbacks of the conventional collecting barrel pressure transmitter using feedback control, and it simplifies the operation when changing the Matsuhachi set value or the collecting barrel pressure set value, Moreover, it is an object of the present invention to provide a collecting barrel pressure transmitter that can obtain an appropriate control gain at the end of ventilation.

[Means to solve the problem]

According to the present invention, there is a Matsuha number setting device that commands the Matsuha number of airflow, and a control that controls the airflow by compressed air stored in an air storage tank based on a Matsuha number setting signal output from the Matsuha number setting device. A collecting shell pressure transmitter for controlling the pressure in a collecting tunnel of a blow-out type wind tunnel, comprising: a collecting shell pressure setting device that outputs a collecting shell pressure setting signal that commands a stagnation point pressure setting value of the collecting shell; A collecting barrel pressure transmitter that outputs the detected stagnation point pressure value of the collecting barrel as a collecting barrel pressure signal, an air storage tank pressure transmitter that detects the pressure of the air storage tank and outputs it as an air storage tank pressure signal, Control calculations are performed on the collecting shell pressure setting signal output from the pressure setting device and the collecting shell pressure signal output from the collecting shell pressure transmitter, and the detected value of the pressure at the stagnation point of the collecting shell is determined by the collecting shell pressure setting device. A feedback control unit that calculates a feedback control signal for controlling to a set value and outputs a valve opening command signal for the pressure regulating valve, and an air storage tank pressure signal and collecting barrel pressure that are output from an air storage tank pressure transmitter. The present invention is characterized by comprising a gain converter that receives the collecting barrel pressure setting signal output from the setting device and calculates a proportional gain for the valve opening command signal based on these signals.

[For production]

According to the present invention, the proportional gain is increased to compensate for the decrease in air volume due to ventilation. That is, the decrease in flow rate gain of the pressure regulating valve is compensated for by increasing the proportional gain. Therefore, it is possible to simplify the operation and obtain optimal gain compensation even when the pressure set value of the collecting barrel is changed or when the air storage tank pressure decreases significantly at the end of ventilation.

Moreover, the value of the set proportional gain can be grasped before ventilation.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. 1, which is a block diagram showing the configuration of an embodiment of the present invention.

The collecting shell pressure transmitter 20 shown in FIG. a feedback control unit 23 that performs proportional and integral calculations on the output of the sinus pressure setting device 21 and the stagnation point pressure of the collecting cylinder, which will be described later, and outputs the result as feedback control No. 1g;
A gain calculation section 24 is provided that adjusts the output gain of the feedback control section 23 based on the output Pt converted into electrical No. 15 by the air storage tank pressure transmitter 8 that detects the pressure of the air storage tank 1. On the other hand, the total pressure (stagnation point pressure) of the collecting shell 4 is converted into an electrical signal by the collecting shell pressure transmitter 7,
The signal is transmitted to the subtracter 22 described above. Also, unlike the conventional device, the setting signal P of the collecting barrel pressure setting device 20 is different from the conventional device. is also directly applied to the gain converter 24, and gain conversion is performed using two signals, Pt and PO, as parameters. As the output of the collecting barrel pressure transmitter 20, a signal of the calculation result of the gain calculation section 24 is transmitted to the pressure regulating valve 3,
The valve opening degree is adjusted.

Here, the reason why the storage tank pressure and the collection barrel pressure set value are used to control the valve opening is as follows.

Originally, in order to control the pressure regulating valve, it is desirable to perform control using the pressure on the upstream side and the pressure on the downstream side of the pressure regulating valve. first,
Looking at the upstream side, the pressure is unstable in the high pressure conduit section upstream of the pressure regulating valve, so the pressure in the storage tank, where the pressure is more stable than here, is estimated as the pressure upstream of the pressure regulating valve. did.

Note that, since the pressure loss due to the high-pressure conduit is small, even if the air storage tank pressure is used, the difference is small and there is no particular problem.

On the other hand, regarding the pressure on the downstream side of the pressure regulating valve, the downstream side of the pressure regulating valve is the collecting shell, but for this pressure, a more stable collecting shell pressure set value is used instead of the collecting shell pressure detected by the collecting shell pressure transmitter. do. This is because the blow-out type wind tunnel is a precision machine manufactured with extremely high precision and it is possible to control the collecting shell pressure according to the set value, so the set value of the collecting shell pressure is used instead.

Next, the relationship between the pressure regulating valve opening degree and the air volume when using the storage tank pressure and collecting shell pressure set values will be described.

A relational expression between the pressure regulating valve opening and air volume is determined according to the characteristics of the pressure regulating valve, but in order to optimally control the pressure regulating valve, an inverse relational expression is created based on this relation, that is, the pressure regulating valve opening is proportional to the air volume. By setting it as a gain, it becomes possible to cancel out the relational expression between the opening degree of the pressure regulating valve and the air volume.

Now, the upstream pressure of the pressure regulating valve is the storage tank pressure P7, and the downstream pressure is the collection barrel pressure set value P. , if the pressure regulating valve opening is θ, then
The air volume X6 determined by these is given by the following formula.

...(1) XG mat C1'・PT・θ ...(2
) Here, k is the specific heat ratio of air, usually -1,4, C1゜0
1' is a constant determined by the pressure regulating valve.

Conventional collecting cylinder pressure side 8 devices, such as the above-mentioned literature, Aerospace Technology Research Institute report TR-647 and JP-A-63-2
The gain compensation performed in 56835 is related to the above choked condition.

Based on this relationship, the gain calculating section 24 described above calculates the storage tank pressure signal P□ sent from the storage tank pressure transmitter 'rA8 and the collecting barrel pressure sent from the collecting barrel pressure setting device 21. Transmitter P. Then, the following calculation is performed which is the inverse relational expression of the above calculation, and the coefficient (■) representing the variable gain in the gain converter 21 is obtained. seek.

PTk+1...(3) However, C2, 02' is a constant.These conditional expressions and gain calculation expressions are calculated by the gain calculation section 24.
stored in memory within.

According to the collecting barrel pressure transmitter as described above, the collecting barrel pressure setting value P. Also, it is determined whether it is a choked state or a non-choked state according to the air storage tank pressure P□, and an equation corresponding to each state is selected and calculated. therefore,
In a choked state where the air storage tank pressures P and r are sufficiently high, performance similar to that of the prior art is achieved using the gain obtained from equation (4), and when the tank is in a non-choked state, the gain is obtained using equation (3).

The collecting barrel pressure transmitter according to the present invention can be configured by combining analog electronic circuits, and can also be realized in part or in whole by an electronic computer.The above embodiments use air as the working fluid, but the present invention Similar effects can be obtained even when using a gas other than air, such as nitrogen or helium.

〔Effect of the invention〕

As described above, according to the present invention, the proportional gain is increased in order to compensate for the decrease in air volume due to ventilation, so when the pressure setting value of the collection barrel is changed or when the ventilation ends, there is a significant decrease in the pressure in the storage tank. Operation can be simplified and optimal gain compensation can be obtained even when in mode mode. Furthermore, since the set value of the proportional gain can be checked before ventilating, drivability is improved and stable operation is possible.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of one embodiment of the collecting shell pressure transmitter according to the present invention, Fig. 2 is a schematic explanatory diagram showing a typical blow-out type wind tunnel, and Fig. 3 is a conventional collecting shell pressure transmitter. FIG. 1... Air storage tank, 2... High pressure conduit, 3... Pressure regulating valve,
4... Collecting cylinder, 7... Collecting cylinder pressure transmitter, 8...
Storage tank pressure transmitter, 20... Collection barrel pressure transmitter, 21
. . . Collection barrel pressure setting device, 23 . . . Feedback control unit, 24 . . . Gain calculator.

Claims (1)

[Claims] A Mach number setter that commands the Mach number of airflow, and control that controls the airflow by compressed air stored in an air storage tank based on a Mach number setting signal output from the Mach number setter. A collecting shell pressure control device for controlling the pressure in a collecting tunnel of a blow-off type wind tunnel, comprising: a collecting shell pressure setting device that outputs a collecting shell pressure setting signal that commands a stagnation point pressure setting value of the collecting shell; , a collecting shell pressure transmitter that outputs a detected stagnation point pressure value of the collecting shell as a collecting shell pressure signal; and an air storage tank pressure transmitter that detects the pressure of the air storage tank and outputs it as an air storage tank pressure signal. , Performing control calculations on the collecting barrel pressure setting signal output from the collecting barrel pressure setting device and the collecting barrel pressure signal output from the collecting barrel pressure transmitter, and determining the detected value of the stagnation point pressure of the collecting barrel. a feedback control unit that calculates a feedback control signal for controlling to the value set by the collecting barrel pressure setting device and outputs a valve opening command signal of the pressure regulating valve; A gain converter receives a tank pressure signal and a collecting barrel pressure setting signal output from the collecting barrel pressure setting device, and calculates a proportional gain for the valve opening command signal based on these signals. Collection barrel pressure control device.