JPH0423043A - Fuzzy arithmetic circuit - Google Patents

Abstract

PURPOSE:To obtain a new fuzzy arithmetic circuit with the high responsiveness by providing two operational amplifiers, a comparison signal, a control part, and a function generating circuit and actuating the operational amplifiers only in a linear area of the arithmetic circuit. CONSTITUTION:When an input signal V1 is inputted to the operational amplifiers OP1 and OP2 respectively, the outputs P1 and P4 of the amplifiers OP1 and OP2 cross the voltage of 0 level at the positions decided by the comparison voltage levels VR and VL respectively. Thus both outputs P1 and P4 rise or fall. These output characteristics are turned into the outputs P2 and P5 having the changed slopes by the regulators VR1 and VR2. The comparators DC1 and DC2 are set at a contact voltage level -VBE and then turned into the outputs P3 and P6 at the negative and positive sides centering on the cross positions decided by the comparison voltage levels VR and VL respectively. At a function generating part FG, the outputs P3, P6 and P7 are inputted to the bases of transistors 5 - 7 respectively and synthesized. Thus the trapezoidal output characteristic VOUT is obtained. Therefore a fuzzy arithmetic circuit using the amplifiers OP1 and OP2 can maintain high speed responsiveness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuzzy arithmetic circuit, and particularly to an arithmetic circuit for generating a trapezoidal membership function in the first half of a fuzzy arithmetic operation.

[Background Art] Recently, control methods using fuzzy inference, so-called fuzzy control, have been considered for application in a wide range of fields and are being put into practical use. For example, the skill of a skilled operator is reflected in the control of a certain controlled device.

Even an unskilled person can easily operate it. Alternatively, attempts are being made to put it into practical use as a method to enable autonomous driving. Along with this, research has progressed into hardware that specifically executes fuzzy operations, and both digital and analog systems are beginning to be provided. A fuzzy arithmetic circuit generally includes an inference section and a conclusion section.

The inference section is divided into antecedent part processing and consequent part processing, and consequent part processing is performed based on the membership function obtained by the antecedent part processing.

[Problems to be Solved by the Invention] Up until now, for example, in the case of digital systems, due to their discrete nature, the continuity of the signal is limited over time.
There is a problem that the level is not maintained. On the other hand, in the case of an analog system, there is a problem in that the circuit is complicated because it is entirely composed of transistors.

Among fuzzy arithmetic circuits, the present invention focuses on arithmetic circuits that generate membership functions in the antecedent part, and has developed an analog arithmetic circuit that contributes to high-speed fuzzy arithmetic operations with a simple configuration by combining operational amplifiers and transistors. This is what we are trying to provide.

[Means to solve the problem] According to the invention, an input signal and a first comparison signal.

a first signal receiving the input signal and the second comparison signal as inputs;
．． the first . The first one shows the second output characteristic. a second differential amplification section, and the first. A fuzzy arithmetic circuit is obtained that includes an adjustment section that makes the gain of the second operational amplifier variable, and a circuit that generates a trapezoidal function using the output of the adjustment section and the third comparison signal manually.

[Work] In the above configuration, first. The second operational amplifier is.

Given two diagonal lines in a trapezoidal function, the first and second comparison signals determine the intersection of the two diagonal lines and the voltage zero level. The adjustment unit also determines the slopes of the two diagonal lines. The function generation circuit generates a trapezoidal function by combining the two outputs from the adjustment section and the third comparison signal.

[Example] The invention will now be described in detail with reference to one drawing.

FIG. 1 shows a membership function generating section which is a main part of an analog type fuzzy arithmetic circuit according to the present invention.

This membership function generating section is for generating a trapezoidal membership function as shown by the thick line in FIG.

This circuit consists of a first operational amplifier OPI which exhibits a first output characteristic such as a straight line a constituting a trapezoidal member pump function shown in FIG. 2, and whose rising position VR is variable;
A second operational amplifier OP2 exhibiting a second output characteristic as shown in FIG. Regulator VR2 and transistors Tri and Tr
2 and a transistor Tr3,
It consists of a second comparator DC2 based on Tr4 and a function generator FG. The function generator FG includes three transistors Tr5.
~ Consists of Tr7. Comparators DC1, DC2 and function generator FG are connected to straight line a and straight line C, as well as straight line b indicating the zero voltage level (FIG. 2).

Straight lines d (FIG. 2) defining the upper side of the trapezoid are combined to output a trapezoidal membership function.

Next, the operation will be explained.

In Fig. 1, when the input signal V1 is input, the operational amplifiers OPI and OP2 are of differential amplification type, so their output characteristics are the output P1 (operational amplifier 0PI) in Fig. 3(a).
, is represented by the output P4 (operational amplifier 0P2) in FIG. 3(b). The output P1 is.

It crosses the voltage zero level and rises at a position determined by the other comparison voltage VR of the operational amplifier OPI. on the other hand.

The output P4 crosses the voltage zero level and falls at a position determined by the other comparison voltage VL of the operational amplifier OP2.

Next, each of the above output characteristics can be changed to the output P2 in FIG. 3(a) by adjusting the regulators VRI and VR2. The slope can be changed as shown by output P5 in FIG. 3(b). At this stage, the intersection position with the voltage zero level does not change.

In the comparator DCI, by setting the base of the transistor Tr2 to the ground potential, the output P2 in FIG. 3(a) is shifted in the decreasing direction by the base-emitter voltage VBE of the transistor Trl, and is determined by the comparison voltage VR. On the negative side of the intersection position, the voltage becomes constant -VBE. As a result, the output is P
It will be expressed as 3. For the same reason, the comparator DC
2, the output P5 in FIG. 3(b) is shifted in the decreasing direction by the voltage VBE, and becomes a constant voltage -VBE on the positive side of the crossing position determined by the comparison voltage 2. As a result, the output is P
It will be expressed as 6.

In the function generator FG, the output P3 is applied to the base of the transistor Tr5, the output P6 is applied to the base of the transistor Tr6, and the third comparison voltage P7 is applied to the base of the transistor Tr7.
(VP VBE) (However.

■, is the voltage value on the upper side of the trapezoidal function)
7 are inputted and combined, the combined output of outputs P3 and P6 becomes voltage VBI, as shown in FIG.
1 synthesis result output V is shifted upward by E. As UT, a trapezoidal output characteristic shown by a dashed line is obtained.

As can be understood from the above description, the arithmetic circuit according to the present invention is characterized in that the operational amplifier operates only in the linear region. Usually, when trying to generate a trapezoidal function as shown in FIG.

It is realized by a combination of an operational amplifier and a diode, but in the conventional ones, the operational amplifier operates not only in the linear region but also in the saturation region. in this case.

The frequency band in which the operational amplifier can respond becomes about one order of magnitude lower than the frequency band when used in the linear region.

On the other hand, the arithmetic circuit of the present invention does not impair the high frequency band of the operational amplifier due to the above-mentioned reasons, and therefore can realize high-speed response.

In the description of the embodiment, a variable resistor is used as a means for adjusting the slope of the outputs PL and P4, but it may also be configured to allow remote setting using digital values using a digital potentiometer or an analog multiplexer. .

[Effects of the Invention] As explained above, the present invention is a new type of fuzzy arithmetic circuit using an operational amplifier.

A simple configuration can provide high-speed response.

Moreover, the slope of the characteristic corresponding to the hatched portion of the trapezoidal function and the intersection position with the voltage zero level can be easily adjusted.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a membership function generating section which is a main part of a fuzzy arithmetic circuit according to the present invention, and FIG. 2 is a diagram showing an example of a membership function generated by the circuit shown in FIG. 1. 3 and 4 are output characteristic diagrams for explaining the generation process of the membership functions shown in FIG. 2, respectively. In the figure, OPI and OF2 are operational amplifiers, and FG is a function generator. Figure 1 Figure 2 Figure 3 (a) (b) Figure 4

Claims (1)

[Claims] 1) First and second operational amplifiers that include first and second operational amplifiers that receive the input signal and the first comparison signal, and the input signal and the second comparison signal, respectively, and exhibit first and second output characteristics. a circuit that generates a trapezoidal function using the output of the adjustment section and a third comparison signal as input; A fuzzy arithmetic circuit comprising: