JPH032911A - Buoyancy controller - Google Patents

Abstract

PURPOSE:To quickly obtain the target altitude or depth based on the present altitude or depth and furthermore to secure the smooth change of buoyancy by deciding the controlled variable of buoyancy with a fuzzy inference based on the deviation between the present altitude or depth and the target one and the time differential value of the deviation. CONSTITUTION:A target value setting means 1 sets the target altitude or depth, and a present value measuring means 3 measures the present altitude or depth to obtain the deviation between the measured present value and the set target value. A time differential value extracting means 4 obtains the time differential value of the deviation, and a buoyancy control means 6 controls the level of buoyancy in response to the given control signal. Then a fuzzy inference means 5 decides the controlled variable of buoyancy from the deviation and the time differential value. Thus the fuzzy inference is carried out. Consequently, the smooth and proper control is secured for the buoyancy. Then the target altitude or depth is attained and kept.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a buoyancy control device for controlling the buoyancy of a balloon, airship, submarine, or the like.

(b) Prior Art Conventionally, when changing the altitude of a balloon or airship, or when changing the depth of a submarine, buoyancy control has been used.

For example, in a hot air balloon, buoyancy is controlled by changing the temperature and volume inside the gas bag by controlling the output of a burner and the exhaust of hot air, and changing the buoyancy of the gas bag. Furthermore, in airships, buoyancy is controlled by controlling the concentration of helium gas in the gas bag and controlling the exhaust gas.

Furthermore, in submarines, buoyancy is controlled by controlling the inflow and discharge of seawater into ballast tanks. In either case, buoyancy control is performed to maintain or shift a predetermined altitude or depth depending on the balance between buoyancy (buoyancy) and own weight.

(C) Problem to be solved by the invention However, in order to move to a target altitude or depth by buoyancy control and further maintain that altitude or depth, it is necessary to set a set (target) altitude or depth (target value). Depending on the deviation between the current altitude or depth (current value) and the changing state of the altitude or depth, appropriate neutral control (tl) must be performed.

However, modeling of the controlled object was difficult, and accurate automatic control was not possible. As a result,) the control becomes inappropriate, and the target altitude or depth is exceeded.
The problem was that it took too long to reach the target altitude or target depth.

The purpose of this invention is to determine appropriate buoyancy according to the deviation between the target altitude or depth (target value) and the current altitude or depth (current value) and the time differential value of the deviation? 1) By converting ffl into fuzzy rules and performing fuzzy inference,
To provide a buoyancy control device that enables smooth and appropriate buoyancy control to quickly reach and maintain a target altitude or depth.

(Means for Solving Problem d1) The buoyancy control device of the present invention comprises a target value setting means for setting a target altitude or depth, a current value measuring means for measuring the current altitude or depth, and a target value and a current value. a deviation extracting means for obtaining a deviation from the deviation, a time derivative extracting means for obtaining a time derivative of the deviation, a buoyancy control means for controlling the magnitude of buoyancy, and a buoyancy control amount determined from the deviation and the time derivative. It is characterized by the provision of fuzzy inference means.

(e) Effect In the buoyancy side i'llll device of the present invention, the target value setting means sets the target altitude or depth, and the current value measuring means measures the current altitude or depth.

The deviation extracting means obtains the deviation between the target value and the current value, the time differential value extracting means obtains the time differential value of the deviation, and the buoyancy control means controls the magnitude of buoyancy according to the applied control signal. Further, the fuzzy inference means determines the buoyancy control amount from the deviation and the time differential value.

As is well known, the fuzzy inference means is composed of a fuzzy operation section that performs fuzzy operations and a defuzzify section that performs definite value operations.The fuzzy operation section is equipped with a membership function generator that follows predetermined fuzzy rules, and It calculates the membership value (belonging value) for the variable to be used, and outputs the inference value calculated based on the result to the defuzzifier. The fuzzy rule is 1
f(x+=^and xz=B...) Lhen(y
= Z), (x+・A and Xff1
・B...) is called the antecedent part, and (y=Z) is called the consequent part. This fuzzy rule is determined empirically based on the deviation between the target value and the current value, the time differential value of the deviation, the buoyancy control amount, and the actual target value response characteristic.

FIG. 8 is a diagram for explaining one known method of outputting inference results according to the above-mentioned fuzzy rules.

Figures (A) and (B) show the two variables (Xl,
The membership function corresponding to X2) is shown, and the same figure (C
) represents the membership function corresponding to the consequent. Here, two membership functions for the antecedent part are shown, but as the types of variables in the antecedent part increase, the number of membership functions increases accordingly. In each figure, the horizontal axis represents the value of the variable, and the vertical axis represents the membership value (degree of belonging).

Now, if the value of the variable x1 of the first item of the antecedent part is xl, then the degree of affiliation is 0.5 (see (A) in the same figure). Also, the value of the variable x2 of the second item of the antecedent part is χ2
°, then the degree of membership is 0.3 (see figure (
See B). In such a case, the fuzzy calculation unit takes the smallest value among the degrees of membership. That is, in the above example, a degree of affiliation of 0.3 is selected. Next, the membership function corresponding to Z is cut off at the above degree of membership of 0.3, and the center of gravity position y° of the lower trapezoidal portion S is determined. The above-mentioned inference is performed for one rule that outputs this y' as an inference result, but generally a plurality of rules are set. In this case, the inference result shown in FIG. 8(C) is output for each rule. Then, the trapezoid parts output for each rule are logically summed, and the logically summed part (Fig. 8 (
The center of gravity y of the shaded area in D) is output as the determined value of the inference.

In the above inference method, the logical product operation rule of the degree of belonging to the antecedent part (operation to select the smaller degree of membership) and the logical sum operation rule of the trapezoidal part to the consequent part are
It is called the ax rule.

In this invention, by executing the above-mentioned inference method using a fuzzy inference means, the motion state of an airship, submarine, etc. can be determined from the deviation between the target value and the current value, and the time derivative of the deviation, and appropriate measures can be taken accordingly. It becomes possible to determine the appropriate buoyancy control amount, and it becomes possible to quickly reach and stabilize the target altitude or depth.

(f) Example The configuration of a buoyancy control device for an airship to which this invention is applied is shown in the first example.
As shown in the figure. In FIG. 1, a target altitude setting device 1 is a device for setting a target altitude, and an altitude measuring device 2 is a device for measuring the current altitude based on atmospheric pressure or the like. The subtraction circuit 3 calculates the measured value of the altitude measuring device 2 from the target value set by the target altitude setting device 1. This circuit calculates the deviation X1 of the current value from the target value by calculating :Ii. The differentiating circuit 4 converts the change in the deviation X1 every predetermined time into a time differential value X2.
This is the circuit required as . Fuzzy inference device 5 has deviation X
1 and the time differential value X2 of the deviation as input variables to perform fuzzy inference and output buoyancy control NY. The buoyancy adjustment device 6 is a device that controls the magnitude of buoyancy according to the given buoyancy control iY.

FIG. 2 shows an inference rule in which the deviation X1 and its time derivative X2 are input variables and the buoyancy control IY is the output deviation in this embodiment.

In Fig. 2, the symbols for deviation The current altitude is a little low compared to the target value. The current altitude is almost the target value. The current altitude is a little high compared to the target value. The current altitude is high compared to the target value. The current altitude is very high compared to the target value. It means.

Regarding the time differential value of deviation A certain PS: The altitude is currently increasing slowly.PM: The altitude is currently increasing. PL: The altitude is currently increasing rapidly.

Furthermore, regarding the buoyancy control amount (Y), which is the content of the matrix, each symbol is as follows: NL: buoyancy is significantly reduced NM: buoyancy is moderately reduced NS: buoyancy is slightly reduced ZR; buoyancy is hardly changed PS : Slightly increases buoyancy PM: Moderately increases buoyancy PL: Significantly increases buoyancy.

In addition, NL, NM, NS expressing the above ambiguous linguistic values
, ZR, PS, PM, and PL are each called a label.

ambiguous linguistic value, i.e. the above label N L = PL
The membership function shown in FIG. 3 is used to express .

FIG. 4 is a block diagram of the fuzzy inference device.

As mentioned above, the fuzzy inference device includes the fuzzy operation section 40.
and a defuzzify section 41. In order to output the inference result Vi for each rule according to each inference rule shown in FIG. It has a membership function generator to output the results. Since each fuzzy operation unit is provided for each rule, a total of 15 fuzzy operation units are used, and the inference results Vi of each fuzzy operation unit are output to the defuzzify unit 41 in parallel.

The fuzzy calculation section has a configuration as shown in FIG. 5(A). Note that this figure shows the configuration of the fuzzy calculation section shown at the top of FIG. 4.

Three general membership function generators 51 as shown
~53, and each membership function generator has deviation ×
A label NL corresponding to 1, a label NL corresponding to time derivative of deviation x 2, and a label PL corresponding to buoyancy control ff1(Y) are input. When this label is input, a general-purpose membership function generator generates a membership function corresponding to the label.

The outputs of the membership function generators 51 and 52, that is, the degree of membership of each term in the antecedent part, are output to the antecedent part AND circuit 54,
Here, the smaller degree of affiliation is selected by the m1ni rule of the mini-max rule described above. The result is sent to the consequent AND circuit 55. The consequent AND circuit 55 applies the inference result from the antecedent AND circuit 54 to the membership function output from the membership function generator 53 to generate a head as shown in FIG. 8(C). A cut is made (a logical product is taken) and a trapezoidal part is output as the inference result.

The defuzzifier 41 has the configuration shown in FIG. 5(B). As shown in the figure, the defuzzifier 41 is composed of an OR circuit 60 and a definite value calculation circuit 61. The OR circuit 60 is a part that calculates the max rule of the mini-max rule, and ORs the trapezoidal outputs (inference results) from each of the 21 fuzzy calculation units, and calculates the result shown by hatching in FIG. 8(D). form an area like this. The determined value calculation circuit 61 determines the center of gravity position from this area and outputs the determined value of the buoyancy control IY.

Next, a specific example of the configuration of the buoyancy adjustment device is shown in FIG. 6th
In the figure, 10 is a comparator that compares the buoyancy control signal Y and the output of the potentiometer 13, and 15 is a comparator that compares the buoyancy control signal Y and the output of the potentiometer 18. The motor 1) rotates forward or reverse depending on the output of the comparator 10. The flow rate adjustment valve 12 is a valve that controls the flow rate of helium gas to the gas bag 14,
It is driven by a motor 1). Potentiometer 13 generates a voltage signal depending on the flow rate. The motor 16 rotates forward or reverse depending on the output of the comparator 15, and the flow rate adjustment valve 17 is a valve that controls the flow rate of exhaust gas from the gas bag 14 to the atmosphere, and is driven by the motor 16. Potentiometer 18 generates a voltage signal depending on the flow rate. With this configuration, if the buoyancy control signal Y is a positive voltage, the servo system consisting of the comparator 10, the motor 1), the flow rate adjustment valve 12, and the potentiometer 13 controls the gas flow rate according to the magnitude of the signal Y. Helium gas is introduced into the bag 14. Furthermore, if the buoyancy control signal Y is a negative voltage, the servo system consisting of the comparator 15, motor 16, flow rate adjustment valve 17, and potentiometer 18 is activated, and the gas in the gas bag 14 is pumped at a flow rate corresponding to the absolute value of the voltage. Exhausted. Therefore, the more positive the signal Y is, the greater the buoyancy is obtained, and the more negative the signal Y is, the lower the buoyancy is.

If Y is 0, no gas flows into or out of the gas bag 14, and the buoyancy remains constant.

Although the buoyancy adjustment device shown in the above embodiment was applied to an airship, it can also be applied to a submarine in the same way. An example of the structure of the buoyancy adjustment device in this case is shown in FIG. In FIG. 7, 20 and 26 are rectifier circuits, which output signals to the amplifier circuit 21 when the buoyancy control signal Y is positive,
When Y is negative, a signal is output to the amplifier circuit 27. The amplifier circuit 21 drives the electromagnetic servo valve 22 according to the magnitude of the positive value of the signal Y. The electromagnetic/swivel valve 22 drives a hydraulic actuator 23 . Hydraulic actuator 23 controls flow rate regulating valve 24 to control the flow rate of high pressure air to ballast tank 25 . On the other hand, the amplifier circuit 27 receives the signal Y
The electric Tjtl servo valve 28 is driven according to the negative magnitude of Tjtl. The electromagnetic servo valve 28 drives a hydraulic actuator 29, and the hydraulic actuator 29 controls a flow rate adjustment valve 30 to control the exhaust flow rate of air from the ballast tank 25.

With this configuration, if the buoyancy control signal Y has a large positive value, high-pressure air is rapidly blown into the ballast tank 25 via the flow adjustment valve 24, and the seawater in the ballast tank is drained. . This provides great buoyancy. Furthermore, if the signal Y has a large negative value, the air in the ballast tank is rapidly exhausted via the flow rate adjustment valve 30, and at the same time, seawater is injected into the ballast tank, reducing the buoyancy. If the signal Y is 0, high-pressure air is not injected and exhausted from the ballast tank 25 and seawater is not injected and drained, and a constant buoyancy is maintained.

Further, when the present invention is applied to a hot air balloon, fuel injection to the burner and hot air exhaust control may be performed in accordance with the buoyancy control signal.

(g) Effects of the Invention According to this invention, the buoyancy control amount is determined by fuzzy inference based on the deviation between the current altitude or depth and the target altitude or depth, and the time derivative of the deviation. The target altitude or depth can be quickly reached from the desired altitude or depth, and there is no excessive increase or decrease in buoyancy (overshoot), resulting in smooth buoyancy changes, which improves the ride comfort for passengers.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a buoyancy control device according to an embodiment of the present invention, FIG. 2 is a diagram showing inference rules set in the embodiment, and FIG. 3 is a diagram showing membership functions. Figure 4 is a block diagram of the fuzzy inference device, Figure 5 (A), CB
) are block diagrams of a fuzzy operation section and a defuzzify section, respectively. FIG. 6 is a configuration diagram of the buoyancy adjustment device when applied to an airship, and FIG. 7 is a configuration diagram of the buoyancy adjustment device when applied to a submarine. Further, FIGS. 8(A) to 8(D) are diagrams for explaining a method of outputting inference results according to fuzzy inference rules. Diagram

Claims (1)

[Claims] (1) A target value setting means for setting a target altitude or depth, a current value measuring means for measuring the current altitude or depth, a deviation extraction means for calculating the deviation between the target value and the current value, and the time of said deviation. A buoyancy control device comprising: a time differential value extracting means for obtaining a differential value; a buoyancy control means for controlling the magnitude of buoyancy; and a fuzzy inference means for determining a buoyancy control amount from the deviation and the time differential value. .