JP2603164B2 - Defuzzifier circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defuzzifier circuit for converting a fuzzy quantity into a definite value in hardware for performing fuzzy inference.

[0002]

2. Description of the Related Art Fuzzy information appears as electric signals distributed on a plurality of lines. Therefore, in order to operate an actuator or the like using these signals, it is necessary to convert an electric signal into an operation amount. This conversion mechanism is called a defuzzifier, and is usually performed by calculating the center of gravity of the fuzzy amount (special operation). Kaihei 2-54301). Hereinafter, the prior art will be described based on the above description. An example of the fuzzy information will be described with reference to FIG. First, elements of fuzzy information are represented by X, and discrete values x ₁ , x ₂ ,..., X _n−1 , x _n
Shall be taken. These elements comprise a plurality of signal lines l
_1, l _2, ..., l output on _n, grade corresponding to each element (function value corresponding to the _{variable) μ 1, μ 2, ...} , μ
_n is represented by the analog voltage or current signal represented on the signal line.

In this case, grades μ ₁ , μ ₂ ,..., Μ _n
Is represented by a voltage. In FIG.
The center of gravity (the position on the x-axis) of the fuzzy information is given by equation (1). (1) As shown in the equation, multiplication,
Addition and division are required. Therefore, in order to obtain the center of gravity only by easy addition of the calculation, the following modification is performed to obtain equation (2), and (2)
The division is omitted so that the denominator in the equation is 1. In short, if you adjust K so that the denominator becomes 1, the center of gravity will be
It can be obtained by equation (3).

[0004] Figure 4 is a specific circuit example, n signal lines l ₁ of the present, l _2, ..., the voltage mu ₁ representing fuzzy information on _{l n, μ 2, ...,} μ n is derived Indicates a state in which Each of these pieces of information is calculated by the graded inference engine 1 by an operation Kμ ₁ , Kμ ₂ ,.
μ _n is calculated, and a weighted addition circuit 2 and a simple addition circuit 3
Is input to Here, in the weighted addition circuit 2, (3)
The equation is calculated and a voltage signal representing the center of gravity is output. On the other hand, the simple addition circuit 3 executes the calculation of the denominator of the equation (2),
The result is input to the voltage adjustment circuit 4. A voltage corresponding to grade 1 is applied to the other input of the voltage adjustment circuit. Therefore, according to the output signal of the voltage adjustment circuit 4,
The coefficient K in the variable grade inference engine 1 is adjusted so that the output of the simple addition circuit 3 is always 1.

[0005]

The prior art described above is
The circuit portion of the fuzzy inference circuit related to the electric signal is controlled so that the output signal of the simple adder circuit to which the electric signals distributed on a plurality of lines are input corresponds to 1. In this case, a grade control means is provided in the membership function circuit to adjust the grade of the membership function. In the case of this type of scheme, the conversion factor is 2
If there are more than one, the membership function circuit cannot be shared and must be provided for each individual conversion element. This is because the grade control signals from all the defuzzifiers cannot be the same. Further, when adjusting the gain of the weighted addition circuit and the gain of the simple addition circuit so that the output of the simple addition circuit corresponds to 1, in the conventional device, an FET is used as a feedback resistor of the operation amplifier.
Is used. However, in this case, the linearity of the FET is insufficient, so that accuracy cannot be obtained, and an expensive variable gain amplifier is actually required. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a defuzzifier circuit that can share a membership function with a plurality of defuzzifiers with a simple circuit configuration.

[0006]

In order to achieve the above object, the present invention multiplies each of electric signals representing fuzzy information distributed on a plurality of lines by a value corresponding to the order of the lines and adds them. Weighted addition circuit, a simple addition circuit that adds the electric signals without weighting, a constant current source connected to the simple addition circuit, a voltage downstream of an addition resistor of the simple addition circuit, and a weight of the weighted addition circuit. And means for setting the voltage downstream of the addition resistor to the same level.

[0007]

An embodiment will be described below with reference to the drawings. FIG.
FIG. 1 is a configuration diagram of an embodiment of a defuzzifier circuit according to the present invention. 1, 2 weighted summing resistor R ₁ a weighted addition circuit, R _2, ..., R _i, ... it is connected between the fuzzy buses 5 through R _N. Of the operational amplifier 7 - The terminal is connected to the common terminal of the weighted summing resistor, + terminal is connected to the common terminal of the simple summing resistor via the resistor R _c. The resistance _Rf is the operation amplifier 7
Is connected between the negative terminal and the output terminal of
_f is output as the conversion current. As can be understood from the above description, the downstream of the weighted addition resistor R _i is connected to the downstream P of the simple addition resistor by the operation amplifier 7. Here, it is imaginarily short-circuited with the downstream P of the simple addition resistor.

[0008] To explain the detail of FIG 2, weighted in the weighted addition circuit 2 adds resistance R ₁ to R _N is the resistance between the fuzzy buses 5 respectively via the transistor QW R _f
In the simple addition circuit 3, the resistor R is connected to the fuzzy bus 5 and the constant current source 6 via the transistor QC.

Next, the operation will be described. First, since the constant current source 6 is connected to the junction P of the simple addition circuit, only a constant current flows through the simple addition circuit. In addition, since the base potential of the transistor QC on the simple addition circuit side and the base potential of the transistor QW on the weighting addition circuit side are imaginarily short due to the circuit configuration, the P-point potential is reflected on the weighted addition circuit side. . For example, when the potential at the point P rises, it acts to limit the current taken into the weighted adder circuit, and when the potential at the point P falls, it acts as a flow of more current. Moreover, since the current flowing to the simple addition circuit side is controlled at a constant current source to be 1, the current l _f flowing to the weighted addition circuit side is the current result of the de-fuzzy fire.

[0010]

As described above, according to the present invention, a constant current source is connected to the simple addition circuit side to supply a constant current, and the potential at the junction on the simple addition circuit side is weighted by the constant current value. Since the configuration is reflected on the adder circuit side, the configuration is simple and the membership function can be shared with a plurality of conversion mechanisms.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a defuzzifier circuit according to the present invention.

FIG. 2 is a detailed view of FIG. 1;

FIG. 3 is a diagram showing an example of fuzzy information.

FIG. 4 is a diagram illustrating a conventional defuzzifier circuit.

[Explanation of symbols]

 1 Variable Grade Inference Engine 2 Weighted Addition Circuit 3 Simple Addition Circuit 4 Voltage Adjustment Circuit 5 Fuzzy Bus 6 Constant Current Source 7 Operational Amplifier

Claims (1)

(57) [Claims] 1. A weighted addition circuit for multiplying each of electric signals representing fuzzy information distributed on a plurality of lines by a value corresponding to the rank of a line and adding them, and without weighting the electric signals. A simple addition circuit for adding
A constant current source connected to the simple addition circuit, and means for setting a voltage downstream of the addition resistance of the simple addition circuit and a voltage downstream of the weighted addition resistance of the weighted addition circuit to the same level. Fuzzy fire circuit.