JPH02130017A - Membership function generation circuit - Google Patents

Abstract

PURPOSE:To facilitate the designation of a membership function, and in addition, to simplify the interface with a binary computer as well by designating the type of the shape (shape of voltage distribution) and the label (language information to designate membership function) of the membership function by a binary code signal. CONSTITUTION:The binary code signals C4C3C2C1C0 of five bits is supplied to a voltage distribution setting circuit 1. A code C4C3 designate the type of the membership function, and the code C2C1C0 designate the label. When the code C4-C0 is provided to the voltage distribution setting circuit 1, it outputs a control signal which controls all analog switches AS so that the voltage distribution to express the membership function of the type designated by the code C4C3 and of the label designated by the code C2-C0 appear to output terminals OT0 to OT24. Thus, the type of the membership function to be generated and the label in each type can be easily designated by the binary code.

Description

DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention By providing a 5-bit pinary fist hood signal of 04 to co, A,
Four types of membership function shapes, S, Z, and π, and NL for each.

A membership function generation circuit that generates a total of 32 voltage distributions with eight labels: NM, NS, ZR, PS, PM, PL, and NG on multiple output lines.

Background of the invention The present invention relates to a membership function generation circuit.

The membership function generation circuit outputs a predetermined membership function signal, and is a fuzzy controller that performs fuzzy inference according to Ifthen rules (Modus Bonens).

It is used in devices called fuzzy computers, fuzzy inference calculation devices, etc. In fuzzy inference, multiple rules are set, and generally each rule uses a different membership function. Therefore, the membership function generation circuit must be configured such that any membership function can be set, and it is preferable that the membership function to be set is also expressed in a form that can be easily specified. Particularly when considering an interface between a digital computer and a membership function generation circuit, it is desirable to be able to specify the membership function to be set using a binary code.

SUMMARY OF THE INVENTION This invention provides two types of membership functions that occur:
An object of the present invention is to provide a membership function generation circuit that can specify a label for each type using a binary code.

The present invention is applied to a membership function generation circuit that expresses a membership function as a distribution of voltage signals appearing on a plurality of output lines. Therefore, each output line corresponds to a variable in the membership function,
Variables are discrete values. The generated membership function is also quantized in multiple stages, so it becomes a discrete value.

A membership function generation circuit according to the present invention includes a reference voltage generation circuit that outputs reference voltages at a plurality of different levels;
A switch including a plurality of analog switches each provided at each intersection of a plurality of reference voltage lines through which the output reference voltages of this reference voltage generation circuit are respectively guided and a plurality of output lines respectively connected to a plurality of output terminals. - Given an array and a multi-bit binary code signal representing the type of membership function and the label of the membership function, the voltage distribution representing the membership function of the type and label specified by this code signal is defined as above. The present invention is characterized in that it includes a voltage distribution setting circuit that controls on/off the analog switch so as to output to the output terminal.

The voltage distribution setting circuit decodes the code signal and
A decoder that outputs signals representing membership function types on different output lines for each type and outputs signals representing membership function labels on different output lines for each label; , and a combinatorial logic circuit for converting each analog-switch into a signal for controlling it to output at its output terminal a voltage distribution of the type represented by it and representing the membership function of the label.

According to this invention, by using two or more configurations, binary
By specifying the type (type) of the shape (voltage distribution shape) of the membership function and the label (linguistic information specifying the membership function) using the code signal, the type specified for multiple output terminals can be specified. The membership function of the given label will be output. Therefore, it becomes easy to specify the membership function to be generated, and the interface with the pinary Φ computer is also simplified.

DESCRIPTION OF THE EMBODIMENTS Figure 1 shows an overview of the configuration of the membership function generation circuit and 1.
This shows the membership functions that occur.

The membership function generation circuit includes a voltage distribution setting circuit 1, a reference voltage generation circuit 2, and a switch array 3. A switch array 3 is connected to the output terminal OT of the membership function generation circuit. Since 25 output terminals OT are provided in this embodiment, numbers from θ to 24 are assigned to these output terminals OT. OTO, OTI when referring to a specific output terminal
.

OT2. . . . The numbers assigned to the output terminals are used.

The membership function is expressed by the voltage distribution appearing at the output terminal OT. Each output terminal will correspond to a discrete variable. In this example, the membership function value is El (OV).

E2 (1,25V), E3 (2,5V)
, E4 (3,75V) and E5 (5V
) is quantized into 5 levels.

The type of membership function is A depending on the shape (voltage distribution shape) of the membership function.

There are four types: S, Z, and π. The function is triangular. The S function increases from a certain position toward the larger variable, and then maintains a constant value. The Z function is the inverse of the S function. The π function has a trapezoidal shape.

Label means the linguistic information that specifies the membership function in each type, here the label represents the eight symbols N
L, NM, NS, ZR, PS.

It is expressed using PM and PL, and NG. N
represents negative, P represents positive, L represents large, N represents medium, and S represents small. Thus, for example, NL represents a large negative value and PS represents a small positive value. Z
R means approximately zero. NG means a function that has a value of zero for any variable.

The lower half of Figure 1 shows a total of 28 types of membership functions (voltage distributions), including four types of Δ, S, Z, and π and seven labels of NL-PL for each type. There is. Here, in order to clarify the shape of each type of membership function, only the membership function of label NL is shown as a solid line.

The reference voltage generation circuit 2 generates voltages at the five levels E1 to E5 described above, and connects the reference voltage lines vL1 to VL5, respectively.
Output to. This reference voltage line VLI-VL5 extends continuously within the switch array 3.

Output terminals OTO to 0T24 in switch array 3
Output lines ELO to EL2 extend continuously from
4 is provided. And the reference voltage line VLL~
Analog switches AS are provided at the intersections (not electrically connected) between VL5 and the output lines ELO to EL24, respectively. These analog switches AS are controlled on and off by control signals output from the voltage distribution setting circuit 1.

An example of the configuration of analog switch AS is shown in FIG. Here, the reference voltage line is VL.

The output line is shown as EL, and the control line that guides the control signal given from the voltage distribution setting circuit 1 is shown as C. The analog switch AS is connected between the reference voltage line VL and the output line EL, and has nMOSFET6 and 9MO8FET7 connected in parallel with each other.
and a NOT circuit 8 for inverting the control signal on the control line C.

The control signal is directly connected to the gate of nMOsFET6.
A control signal inverted by a NOT circuit 8 is applied to the gate of the O8FET 7. When the control signal is at H level, this analog switch AS is turned on.

The voltage distribution setting circuit 1 is supplied with a 5-bit binary equal code signal C4C3C2CIco. As shown in FIG. 3, code C4C5 specifies the type of membership function and code C2C1Co specifies the label. The voltage distribution setting circuit 1 has codes 04 to co
all analog switches such that, when given, a voltage distribution of the type specified by code C4C5 and representing the membership function of the label specified by codes 02 to co appears at the output terminals OTO to 0T24. Outputs a control signal to control the AS.

Therefore, voltage distributions representing a total of 32 types of membership functions of 4 types and 8 labels are generated from this membership function circuit according to codes 04 to co. Strictly speaking, all types of labels NG have the same shape, so 29 voltage distributions occur. This fixes the type by code C4°C and code 02
This is because eight types of labels can be set using the three bits of ~C0.

FIG. 4 shows a part of a configuration example of a voltage distribution setting circuit and a part of a membership function to be output. Here, the membership function of label NL is output. Since the label is fixed to NL (C2C1Co-00
0), the circuit of FIG. 4 will not work for other labels. That is, this circuit shows a simplified specific example that is applied only when the label is NL.

The voltage distribution setting circuit 1 is composed of a decoder 4 and a combinational logic circuit 5. Decoder 4 has code 04~co
is given. The decoder 4 decodes the input code C4C5 and outputs the result by setting one of four output lines provided according to the type of membership function to H level. Similarly, the decoder 4 has eight output lines corresponding to the labels, and outputs an H level signal to one of the output lines depending on the input code C2CIco.

The combinational logic circuit 5 is constituted by a combination of an AND circuit and an OR circuit, and the output run of the decoder 4 is connected as an input line. This circuit 5 then outputs a signal for controlling the analog switch AS in accordance with the output of the decoder 4.

For example, if the label NL of the function is specified (C4C
3C2CIco-00000), the state of the analog switch AS will be explained. Each analog switch AS
In order to distinguish between 10~17.20~2
7.30 to 36.41 to 45.5 (numbered 1 to 57. At the output line ELO, the analogue switch A S 20 is turned on, and the output terminal OTO has a value of 1.2
A voltage of 5V appears. In the next output line ELL, A
S31 turns on and 2.5V appears on OTI. Similarly, AS42 is on output line EL2, AS53 is on output line EL3, and AS is on output line EL4.
44, A S 85 on output line EL5, A32B on output line EL8, and A S on output line EL7.
S17 is turned on, and the output terminals OT2 and O
T3, OT4, OT5.

OT6. 5. OT7 has a voltage of 3.75V, respectively. O
V, 3.75V, 2.5V, 1.25V,
OV appears.

In the case of label NG, that is, C2CIc.

-111, the analog switch A S 10°A S 11. A S 12. A S 13.
A S 14. A S 15゜ASlB, AS
17 are respectively turned on and all output terminals OT are Ov.
The voltage will be .

[Brief explanation of the drawing]

Figure 1 shows the membership function generation circuit and its output signals in relation to each other, Figure 2 is a circuit diagram showing an example of the configuration of an analog switch, and Figure 3 shows the types and types of codes and membership functions. FIG. 4 is a diagram showing the relationship between the voltage distribution setting circuit and the output membership function. 1... Voltage distribution setting circuit. 2...Reference voltage generation circuit. 3...Switch array. 4...Decoder. 5... Combinational logic circuit. VL, VLI -VL5-...Reference voltage line. EL, ELO~EL24...Output line. OTO~0T24...Output terminal. AS: Analog switch. that's all

Claims (2)

[Claims] (1) A reference voltage generation circuit that outputs a plurality of reference voltages at different levels, a plurality of reference voltage lines to which the output reference voltages of this reference voltage generation circuit are respectively guided, and a plurality of outputs each connected to a plurality of output terminals. A switch array including a plurality of analog switches, one at each intersection with a line, and a multi-bit binary code signal representing a membership function type and a membership function label; A membership function generation circuit comprising: a voltage distribution setting circuit that controls on/off the analog switch so as to output a voltage distribution of a type specified by and representing a label membership function to the output terminal. (2) The voltage distribution setting circuit decodes the code signal and outputs a signal representing the type of membership function on a different output line for each type, and a signal representing the label of the membership function for each label. a decoder for outputting on different output lines; each analog,
The membership function generation circuit according to claim 1, comprising: a combinational logic circuit that converts the signal into a signal for controlling a switch;