JPH04335437A - Fuzzy production rule adjusting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for adjusting fuzzy production rules in a fuzzy inference system that draws conclusions from ambiguous and uncertain information and knowledge.

0002

2. Description of the Related Art Fuzzy inference systems using fuzzy set theory have been proposed as inference systems for drawing conclusions from ambiguous and uncertain information and knowledge.

Fuzzy inference systems use an inference method that uses fuzzy sets to describe ambiguous values that cannot be clearly defined, such as ``large'' and ``small'' in production rules. Production rules that allow such descriptions are called fuzzy production rules. The description ``large'' can be written, for example, as shown in FIG. 2 using the membership function of fuzzy set theory. However, the horizontal axis is a value obtained by normalizing the physical quantity handled by the maximum value, and the vertical axis is a quantity (referred to as grade) representing the degree of "largeness". Next, an example of the fuzzy inference method will be explained using diagrams. FIG. 3 is a diagram illustrating an inference method when the number of rules is 2, 2 inputs, and 1 output. Rule 1 is “IF (
Input 1 is A) THEN (Output is B)
, Rule 2 is "IF (input 1 is C) and (input 2 is D) THEN (output is E)", and A
, B, C, D, and E are shown in Fig. 3(a), (b), (c), (d
), (e) are described by membership functions shown by solid lines. A case will be explained in which the output z is inferred when x is input to input 1 and y is input to input 2. A of x,
Find the grades α, β, and γ of C and y for D. For rule 1, B is weighted by α (degree of match of rule 1), and for rule 2, E is weighted by the smaller value of β and γ (degree of match of rule 2), and the membership function shown by the dotted line is Obtain B' and E'. B' and E' are shown in Figure 3.
The membership functions of the inference results are obtained by superimposing them as shown in (f), and the center of gravity, that is, the position where the left and right areas are equal, is set as the output Z of the inference results. In addition to weighting, there are other ways to obtain B' and E', such as truncating B and E (taking MIN) based on the matching degree of each rule, and
) has been proposed as a method of obtaining the inference result Z from the inference result by taking the position of the peak of the membership function of the inference result on the horizontal axis.

[0004] This fuzzy inference method makes it possible to
, it is possible to obtain inference results for input values from fuzzy production rules with vague descriptions that cannot be clearly defined, such as "small". However, in order to obtain favorable inference results for input values, fuzzy production The shape of the membership function in the rules needs to be adjusted. The present invention relates to a device for adjusting this fuzzy production rule. Conventionally, a method has been adopted in which the values of parameters (endpoint coordinate values, equations, etc.) that determine the shape of the membership function are directly input using a keyboard or mouse.

[0005] Fuzzy inference systems using fuzzy set theory are described in 14 of ``Introduction to Fuzzy Systems'' (co-authored by Terano, Asai, and Kanno) published by Ohmsha in 1987.
It is described on pages 9 to 155.

[0006]

[Problems to be Solved by the Invention] However, the fuzzy production rule adjustment device using such a method has the following problems to be solved.

[0007] In order to adjust the membership function, it is necessary to directly input values of parameters that determine the shape of the function, such as end point coordinate values and equations, which means that the production rule cannot be set to ``large'' or ``small''. This goes against the advantage of fuzzy inference systems in that they can be described using ambiguous values that cannot be clearly defined, such as, etc., and in the end, specific values must be manipulated for adjustment. An object of the present invention is to solve such conventional problems.

[0008]

[Means for Solving the Problems] A fuzzy production rule adjustment device according to the present invention includes an adjustment command input section into which adjustment commands in a notation format similar to natural language are inputted from an operator, and a control command input section that is set in advance for the adjustment commands. and a membership function adjustment unit that determines the adjustment amount of the output membership function by performing fuzzy inference based on the adjustment fuzzy production rules that have been set. It is preferable that the adjustment fuzzy production rule receives the shape of the current output membership function as an input and outputs an adjustment amount of the output membership function. It is also preferable that the adjustment fuzzy production rule receives the shape of the current output membership function and the previous adjustment command as input, and outputs the adjustment amount of the output membership function.

[0009]

[Operation] In the fuzzy production rule adjustment device of the present invention, the operator who performs the adjustment can input an adjustment command in a notation format similar to natural language (for example, "move it a little more to the right"), and the device will make the adjustment. Fuzzy production rules (referred to as adjustment fuzzy production rules) that have been set and stored in advance in order to adjust membership functions (referred to as output membership functions) in a fuzzy inference system that is Based on this, fuzzy inference is performed to determine the adjustment amount of the output membership function.

[0010] In the human sense, it is the same as "slightly shift to the right"
Even with this command, the amount of movement differs slightly depending on the current position. For example, the operator often intends to move a larger amount to the right when the object is currently on the left than when it is currently on the right. In order to approximate such a human feeling, the fuzzy production rule for adjustment in the fuzzy production rule adjustment device according to claim 2 uses the shape of the current output membership function as input and outputs the shape of the output membership function. Adjustment amount.

[0011]Furthermore, even with the same command ``slightly shift to the right'', the amount of movement will differ slightly depending on the previous command to the human sense. For example, if the command was the same last time, the operator often intends the amount of movement to be smaller than if it was not the same command. In order to approximate such a human feeling, the fuzzy production rule for adjustment in the fuzzy production rule adjustment device according to claim 3 inputs the shape of the current output membership function and the previous adjustment command, and outputs the output from the output. This is the adjustment amount for the membership function.

0012

Embodiments Examples of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the fuzzy production rule adjustment device and fuzzy inference system of the present invention. The fuzzy production rule adjustment unit 1 includes an adjustment command input unit 11, an adjustment fuzzy production rule storage unit 12, an adjustment fuzzy inference unit 13, a membership function transformation unit 14, and a previous adjustment command storage unit 15. . In addition, fuzzy inference system section 2
is composed of a membership function storage section 21, an adjusted membership function storage section 22, and a fuzzy inference section 23. This is a block diagram of the invention according to claim 3,
According to the second aspect of the invention, the previous adjustment instruction storage section 15 and its associated functions are removed from the fuzzy production rule adjustment section 1. Regarding the invention according to claim 3, the functions of each part will be explained. The functions of each part will be explained when the operator performing the adjustment inputs an adjustment command to "shift a little more to the right." It is assumed that the adjustment fuzzy production rule storage unit 12 stores fuzzy production rules for adjustment that are heuristically determined in advance and are close to human sensations.

The adjustment command input unit 11 sends adjustment commands input by an operator who adjusts rules to the fuzzy inference unit 13 and the previous adjustment command storage unit 15. The adjustment fuzzy inference unit 13 selects a plurality of fuzzy production rules for the input adjustment command “shift a little more to the right” from among the rules stored in the adjustment fuzzy production rule storage unit 12, and selects them. Using the rules, fuzzy inference is performed using the shape of the current output membership function stored in the membership function storage section 21 and the previous adjustment instruction stored in the previous adjustment instruction storage section 15 as input. Then, the adjustment amount of the output membership function is inferred and sent to the membership function transformation unit 14. The membership function transformation unit 14 transforms the shape of the membership function stored in the membership function storage unit 21 based on the received adjustment amount of the output membership function, and transforms the shape of the membership function stored in the membership function storage unit 21.
to be memorized. The fuzzy inference section 23 performs fuzzy inference using the membership functions in the adjusted membership function storage section 22 and outputs the inference results.

Although the fuzzy production rule adjustment device and fuzzy inference system according to the present invention have been described above based on embodiments, these descriptions are not intended to limit the present invention. There are many possible input means for the adjustment command input unit 11, such as a keyboard, a mouse, and voice. Further, although the adjustment command has been described using "shift a little to the right" as an example, it is obvious that other adjustment commands such as "tilt a lot to the left" or "extend a little to the right" can be used. Furthermore, in this embodiment, the adjustment fuzzy inference unit 13 and the fuzzy inference unit 23 are described as separate blocks, but if the same fuzzy inference method is adopted, the structure is simpler if they are represented by one block. Needless to say.

[0015]

[Effects of the Invention] As described above, according to the present invention,
The operator who performs the adjustment does not have to directly input the value of the parameter that determines the shape of the function, such as end point coordinate values or equations, but can input the adjustment command in a notation format similar to natural language, and the operator can create a shape that is similar to human senses. can provide a fuzzy production rule adjustment device that can adjust membership functions.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a fuzzy production rule adjustment device and a fuzzy inference system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a membership function representing "large".

FIG. 3 is a diagram for explaining conventional fuzzy inference.

[Explanation of symbols]

1 Fuzzy production rule adjustment section 2
Fuzzy inference system unit 11 Adjustment command input unit 12 Adjustment fuzzy production rule storage unit 13 Adjustment fuzzy inference unit 14 Membership function transformation unit 15 Previous adjustment command storage unit 21 Membership function storage unit 22 Adjustment membership function storage unit 23 Fuzzy Reasoning part

Claims (3)

[Claims] [Claim 1] An adjustment command input section into which adjustment commands in a notation format similar to natural language are input from an operator, and fuzzy inference based on fuzzy production rules for adjustment set in advance for the adjustment commands. 1. A fuzzy production rule adjustment device, comprising: a membership function adjustment section that determines an amount of adjustment of an output membership function by performing the following steps. 2. The adjustment fuzzy production rule according to claim 1, wherein the shape of the current output membership function is input and the output is the adjustment amount of the output membership function. Production rule adjustment device. 3. The adjustment fuzzy production rule is characterized in that the shape of the current output membership function and the previous adjustment command are input, and the output is the adjustment amount of the output membership function. 1. The fuzzy production rule adjustment device according to 1.