JPH05115188A - Servo motor controller - Google Patents

Abstract

PURPOSE:To obtain a servo motor controller in which control resolution is enhanced by providing a plurality of analog circuits having different gains and no discontinuation nor step occur in the joint region of split control characteristics. CONSTITUTION:The servo motor controller comprises a plurality Of analog circuits 1a, 1b for performing signal conversion of commonly inputted analog speed command voltages with different gains and offsets, a selector 12 and an A/D converter 2 for sequentially selecting the outputs from the plurality of analog circuits and quantizing thus selected outputs, and a fuzzy inference unit 13 for subjecting a plurality of data outputted from the A/D converter 2 to synthesis processing to produce a single speed command data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo motor control device, and more particularly to a servo motor control device having a plurality of analog signal conversion circuits and fuzzy inference means.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram of a conventional general servo motor controller. In the figure, 1 is an analog circuit for converting an analog speed command voltage, which is an input signal, into a voltage signal that can be supplied to the A / D converter 2 in the next stage. As the analog speed command voltage, the forward rotation command voltage range is 0V to + 10V, and the reverse rotation command voltage range is 0V to
-10V, the input range of A / D converter 2 is 0 to +5
Suppose that it is V. In this case, the reverse rotation command maximum voltage of −10 V is the input voltage of the A / D converter 2 of 0 V, and the rotation stop command voltage of 0 V is the input voltage of the A / D converter 2 of +2.
-10V so that the positive rotation command maximum voltage + 10V becomes 5V, which is the input voltage of the A / D converter 2 + 5V.
~ 0V ~ + 10V input voltage linearly corresponding to 0V ~
Converted to an output voltage of + 2.5V to + 5V. Specifically, the above voltage signal can be converted by an analog circuit that adds an offset voltage of +10 V and amplifies a gain of 0.25.

Reference numeral 2 in FIG. 9 is an A / D converter. In this example, an input voltage of 0 to +5 V is converted to 0 to 4 with a resolution of 12 bits.
The description will be given assuming that the data is converted into 096 digital data and is output. Reference numeral 3 is an input gain setting device that converts the output data of the A / D converter 2 into internal speed command data.
Since the output data of the D converter 2 are all positive number data, the positive rotation is converted into positive number data, and the reverse rotation is converted into negative number data. The output of the input gain setting device 3 becomes the internal speed command data V _ref . In FIG. 9, 4 is a speed control amplifier, 5 is a current control amplifier, 6 is a current detector, 7 is a servo motor, 8 is an encoder, 9 is a differentiator for calculating speed from an input signal from the encoder 8, 10a and 10b.
Is a subtracter for outputting the difference between the two input signal values, and 11B is a speed command input unit incorporating the above-mentioned devices 1 to 3.

The operation of FIG. 9 will be described. Now, the correspondence between the input analog speed command voltage and the rotation speed of the servo motor 7 is as follows. When the speed command voltage is + 10V, the positive rotation speed is 2000 rpm, and the speed command voltage is -10V. At this time, the reverse rotation speed shall be 2000 r / m. The number of output pulses of the encoder 8 is 3000 pulses / revolution (hereinafter referred to as p / r), and the differentiator 9 counts the number of pulses output from the encoder 8 every 20.48 milliseconds (hereinafter referred to as ms). , The difference between the current count value and the previous count value is calculated, and this calculated value is used as the rotation speed of the servo motor 7.

Now, the servomotor 7 has a positive rotation of 2000.
When r / m, the calculated value of the differentiator 9 becomes 2048 pulses (P) every 20.48 ms according to the following equation (1).

[0006]

[Equation 1]

FIG. 10 is a conversion characteristic diagram of the input voltage and the output data of the A / D converter 2 of FIG. 9, and the horizontal axis represents the input voltage of the A / D converter 2 and the analog speed corresponding thereto. The command voltage (inside the lower bracket) is shown. The analog circuit 1 inputs the analog speed command voltage -10V as described above.
After adding an offset voltage of + 10V to ˜0 to + 10V, the voltage is converted by amplifying with a gain of 0.25, and a voltage output of 0 to +2.5 to + 5V is supplied to the A / D converter 2. .. The A / D converter 2 has the input voltage 0 to +
The converted output data 0 to 2048 to 4096 shown in FIG. 10 are output for 2.5V to + 5V. Since all the output data of the A / D converter 2 are positive number data, the positive rotation is converted into positive number data, and the reverse rotation is converted into negative number data. Therefore, in the input gain setting unit 3 in the next stage, the offset value- Two
Only 048 is added, and the input / output gain is 1: 1. Therefore, from the output of the input gain setter 3, -2
Speed command data within the range of 048 to 0 to +2048 will be output. The speed command input unit 11B has the above 1 to
It is composed of 3 devices.

For the speed command input section 11B configured as described above, the analog speed command voltage is now +
When 10 V is input to the analog circuit 1, the speed command data V _ref output by the input gain setting unit 3 becomes +2048 and is supplied to the positive side input of the subtractor 10a. Subtractor 10a
The velocity feedback data V _fb output from the encoder 8 via the differentiator 9 is supplied to the negative side input of
The subtractor 10a supplies the deviation signal (V _ref -V _fb ) of both signals to the speed control amplifier 4.

The speed control amplifier 4 uses the deviation signal (V _ref
-V _fb ) is controlled so that it becomes zero, and the current control amplifier 5 supplies the deviation signal between the output of the speed control amplifier 4 and the output of the current detector 4 which is supplied from the subtractor 10b so as to become zero. Then, the torque of the servo motor 7 is controlled. And finally, the velocity feedback data V output from the differentiator 9
_fb is +2048, that is, the rotation speed of the servo motor 7 is 2000 r / m which is a positive rotation.

In the servo motor control device shown in FIG.
When an analog speed command voltage is input to control the speed of a servomotor, the speed of the A / D converter (that is, how many bits) is given because it is internally given as digital speed command data V _ref via the A / D converter. Will determine the speed resolution of the servo motor. Therefore, the use of a high resolution A / D converter in order to improve the control resolution of the servo motor has a drawback of increasing the cost of the apparatus. The "motor drive control device" disclosed in JP-A-2-23083 is a publicly known document relating to a technique for improving the above-mentioned drawbacks.

FIG. 11 is a block diagram showing the configuration of the motor drive control device disclosed in the above-mentioned publicly known document, and 21 is a CPU.
(Central signal processing device), 22 is a D / A converter, 23 is an amplifier, 24 is a motor, 25 is an electric detector, 26 is a filter, and 27 is an operational amplifier. And the operational amplifier 2
7 and the input resistor R ₁ to the operational amplifier 27, the feedback resistors R ₂ and R ₃ , and the analog switch 30 that short-circuits or opens the feedback resistor R ₂ , a variable gain amplifier having two large and small gains is provided. It is configured. 28 is S
/ H (sample and hold) circuit, and 29 is an A / D converter.

The operation of FIG. 11 will be described. Electric detector 25
Detects the value of the load current of the motor 24, and the filter 26 smoothes the detected load current value and supplies it to the operational amplifier 27 via the input resistor R ₁ . In this case, the CPU 21 controls the opening and closing of the contacts of the analog switch 30 to control the gain of the variable gain amplifier as follows. That is, CPU
21 is a predetermined load current value (for example, 4.6).
During the load region higher than A), the analog switch 30
And the gain of the variable gain amplifier is set to G ₁ =
Keep as small as R ₃ / R ₁ . The analog voltage output from the variable gain amplifier in this state and obtained through the S / H circuit 28 is supplied to the CPU 21 as quantized data by the A / D converter 29 with conventional resolution.

The CPU 21 recognizes the current value of the motor 24 from the input quantized data, and through the D / A converter 22 and the amplifier 23, the current value becomes a value according to the target load. The current supplied to the motor 24 is controlled. Then, the CPU 21 contacts the analog switch 30 when the current value of the motor 24 recognized from the continuously input quantized data is in a load region lower than the predetermined load current value (4.6 A described above). Is opened, and the gain of the variable gain amplifier is G ₂ = (R ₂ + R
₃ ) / R ₁ and increase. .

The A / D converter 29 supplies the analog voltage amplified by such a large gain to the CPU 21 as quantized data with the same resolution as described above. CPU
21 recognizes that the data in this case is data based on a large amplification gain and controls the current of the motor 24. A / D conversion of a voltage signal amplified with a large gain in the low load area is to A / D convert a signal in a narrower area than a signal in the entire area (full range) up to that point with the same resolution. And has a substantially high resolution A
This is equivalent to using the / D converter. Therefore, the control resolution in the low load region is improved.

[0015]

However, in the drive control device for a motor disclosed in Japanese Patent Laid-Open No. 23083/1990, the control resolution in the low load region is improved, but an analog operational amplifier is used. Since there are errors or drifts in the gain or offset values in the circuit, and these are not always completely compensated for, the control characteristics become discontinuous near the gain switching point at the boundary between the high load region and the low load region (Fig. However, there is a problem that the motor cannot be smoothly controlled.

The present invention has been made in order to solve the above problems, and a servo which improves the control resolution by providing an analog circuit having a plurality of gains and does not have a discontinuous control characteristic in the vicinity of the gain switching point. The purpose is to obtain a motor control device.

[0017]

A servo motor control device according to the present invention inputs a speed command voltage signal for instructing a rotation speed of a servo motor according to a polarity and a voltage value of an analog voltage in common, and responds to the input signal. A plurality of analog circuits that perform signal conversion by voltage amplification with different gains and addition of different offset voltages, and a plurality of converted signals that are respectively output from the plurality of analog circuits are sequentially selected. Selection and quantization means for sequentially converting to digital data, and fuzzy inference means for obtaining a single speed command data by subjecting a plurality of digital data sequentially output from the selection and quantization means to synthetic operation processing by fuzzy inference It is equipped with and.

[0018]

According to the present invention, the plurality of analog circuits are commonly input with the speed command voltage signals for instructing the rotation speed of the servo motor by the polarity and the voltage value of the analog voltage. Signal conversion is performed by voltage amplification and addition of different offset voltages. The selecting and quantizing means successively selects a plurality of converted signals respectively output from the plurality of analog circuits, and sequentially converts the selected signals into digital data. The fuzzy inference means performs a synthetic operation process by fuzzy inference on a plurality of digital data sequentially output from the selecting and quantizing means to obtain a single speed command data.

[0019]

EXAMPLES Example 1. 1 is a block diagram of the configuration of a servo motor control device according to a first embodiment of the present invention. In the figure, 2 to 10b are the same devices as the conventional device of FIG. Reference numerals 1a and 1b are # 1 and # 2 analog circuits that perform signal conversion on common input signals by amplification with different gains and addition of different offset values, and the signal conversion characteristics thereof will be described with reference to FIG. Reference numeral 12 is a selector which alternately selects the output of the # 1 analog circuit 1a and the output of the # 2 analog circuit 1b and supplies the output to the A / D converter 2. By performing the selection operation at all times by time division, The outputs of the analog circuits 1a and 1b converted into two different signals with respect to the input signal are always supplied to the A / D converter 2.

Reference numeral 13 in FIG. 1 is a fuzzy reasoner, which outputs A / D signals from the outputs of the two analog circuits 1a and 1b.
2 supplied via converter 2 and input gain setter 3
The composite arithmetic processing by fuzzy inference is performed from one input data, and a single speed command data V _ref is output. A smooth speed control characteristic can be obtained in the boundary area between the high speed area and the low speed area of the servo motor by the synthetic operation processing based on the above fuzzy inference. The details will be described with reference to FIGS. 3 and 4. The A / D converter 2 in FIG.
Input voltage of + 5V is 0-102 with 10-bit resolution.
4 will be described as being converted into digital data and output.

FIG. 2 is a signal conversion characteristic diagram of the two analog circuits shown in FIG. 2A shows the input / output signal conversion characteristic of the # 1 analog circuit 1a, which is the same as the signal conversion characteristic of the analog circuit 1 of FIG. That is, input voltage of speed command -10V to 0 to + 10V
Is linearly converted into the corresponding output voltage of 0V to + 2.5V to + 5V. FIG. 2B shows the input / output signal conversion characteristic of the # 2 analog circuit 1b, in which the range of the speed command input voltage is divided into (1) -10V.
~ -2V, (2) -2V ~ 0 + 2V, (3) + 2V ~
The signal voltage is converted in three ranges of + 10V. Therefore, first, it is determined which of the above three ranges the speed command input voltage belongs to, and the result of the determination
(1) Output voltage is always 0V in the input voltage range of -10V to -2V, and (2) Input voltage is -2V to 0 to + 2V.
In the range of, the output voltage linearly corresponds to 0V to +2.5
The signal voltage is converted to V to + 5V so that the output voltage is always + 5V in the range (3) where the input voltage is + 2V to + 10V.

In this example, since the A / D converter 2 has a resolution of 10 bits, the input voltage to the A / D converter 2 is 0 to 0.
+ 2.5V to + 5V is output data 0 to 512 to 1024
Is converted to. The vertical axis of (a) of FIG. 2 shows A / D converted output V _a corresponding to the output voltage of the # 1 analog circuit in parentheses, and similarly, the vertical axis of (b) of FIG. The output voltage of the analog circuit and the corresponding A / D conversion output V _b are shown in parentheses.

FIG. 3 is an explanatory diagram of the membership function in the fuzzy reasoner 13 of FIG. The vertical axis of the figure is the degree of certainty in the Fuzzy representation,
Shown as a number between 0 and 1. The horizontal axis shows the analog speed command voltage and the corresponding A / D conversion output data in the lower bracket. In FIG. 3, H
And L are membership functions, respectively, and the value of the membership function H (degree of certainty) when the analog speed command voltage is in the range of -10V to -2V and + 2V to + 10V.
Is 1. In addition, the value of the membership function L is 1 in the range of about 1V before and after the speed command voltage is 0V as the center.
Is. However, in the range of the speed command voltage from -2V to about 1V in the positive direction and from + 2V to about 1V in the negative direction, the values of the membership functions H and L follow a predetermined slope straight line,
It has changed from 1 to 0 or from 0 to 1.

FIG. 4 is a connection explanatory diagram of different speed control characteristics according to the first embodiment of the present invention. In the figure, V _a is # 1
Digital data converted from the output of the analog circuit 1a via the A / D converter 2, _Vb is # 2 analog circuit 1b
Is the digital data converted from the output of the same through the A / D converter 2. In FIG. 4, the vertical axis represents the rotation speed,
The horizontal axis is the analog speed command voltage, and the command voltage is -1.
In the range of 0V to -2V and + 2V to + 10V, the above V _a
The speed control characteristic by the command voltage from -2V to +
In the range of 2V, the speed control characteristic by _Vb is shown.

In a normal analog circuit, there are errors and drifts in the gain or offset value, and these are not completely compensated, so that a discontinuity or a step is generally generated at the switching point of the two control characteristics. is there. Figure 4
The discontinuous step is generated at the analog speed command voltage of -2V and + 2V, and the fuzzy reasoning of the present invention will be described later for smooth connection.

The operation of FIG. 1 will be described with reference to FIGS. Now analog speed command voltage -10V to 0 to +10
When V is commonly input to the # 1 analog circuit 1a and the # 2 analog circuit 1b, the # 1 analog circuit 1a follows 0V to +2.5 according to the signal conversion characteristic shown in FIG.
The converted voltage of V to +5 V is output, and the # 2 analog circuit 1
b indicates three ranges of the input voltage (1) -10V to -2V, according to the signal conversion characteristic shown in FIG.
(2) -2V to 0 to + 2V, (3) + 2V to + 10V, respectively, converted voltage (1) 0V, (2) 0
Outputs V to + 2.5V to + 5V, (3) + 5V.

The selector 12 always alternately selects the output of the # 1 analog circuit 1a and the output of the # 2 analog circuit 1b in a time-divisional manner and supplies the selected output to the A / D converter 2. 2 outputs digital data 0 to 512 to 1024 obtained by quantizing the input voltage 0 to +2.5 to + 5V. here#
The digital data obtained by quantizing the output of the first analog circuit 1a is V _a , and the digital data obtained by quantizing the output of the # 2 analog circuit 1b is V _b . The input gain setting unit 3 adds −512 as an offset value to the output data V _a or V _{b of the} A / D converter 2 to obtain V _a
−512 or V _b −512 (as a data value, −51
The output data of 2 to 0 to 512) is supplied to the fuzzy reasoner 13.

The fuzzy reasoner 13 performs the following fuzzy operation. (1) If the quantized data V _a output from the # 1 analog circuit 1 _a is a membership function H (hereinafter, if V _a =
H ten)), and speed command data V _ref1 based on V _a is calculated from the following equation (2).

[0029]

[Equation 2]

Here, the symbol * is a multiplication symbol, and is expressed by equation (2).
At the input data (V _a −
512) is multiplied by 4 for a 10-bit A / D converter 2
This is for the purpose of converting the output data of 1 to the output data of the 12-bit A / D converter.

(2) Next, if the quantized data V _a is a membership function L (if V _a = L then), then V
_The speed command data V _ref2 based on _b is calculated from the following formula (3).

[0032]

[Equation 3]

In the equation (3), the input data ( _Vb- 512) from the input gain setting unit 3 is multiplied by 4/5 because the speed command voltage range (-2V to + 2V) is the entire range (-). This is because it corresponds to 1/5 of (10 V to +10 V).

(3) Next, from the speed command data V _ref1 and V _ref2 based on the calculated V _a and V _b and the values of the corresponding membership functions H and L, respectively, fuzzy by the following equation (4). A single speed command data V _ref is obtained by performing a synthetic operation by inference.

[0035]

[Equation 4]

In this case, the denominator (H + L) of equation (4)
Has a value of 1.

As an example, the analog speed command voltage is +
At 10 V, V _a = 1024, V _b = 1024 from the signal conversion characteristics of FIGS. 2A and 2B, and the membership functions H and L shown in FIG. 3 have values of H = 1 and L =. Since 0 is obtained respectively, by substituting these values into the equation (4), the speed command data V _ref = 2048 can be obtained by the equation (5).

[0038]

[Equation 5]

The speed command data V _ref = 204
The rotation speed of the servo motor 7 corresponding to 8 is 2000 r / m of positive rotation.

The major features of using the speed command data V _ref obtained as a result of the synthetic operation processing by fuzzy inference in this way are (1) improvement of control resolution in the low speed region, and (2) high speed region and low speed region. This means that a smooth connection can be achieved without a discontinuous step in the control characteristics at the boundary between the and.

Explaining the first characteristic, the control resolution is 2000r / m / 512LS in the range of analog speed command voltage of -10V to -2V and + 2V to + 10V.
The approximate value of B is 3.91 r / m / LSB, but the control resolution is 400 r / m / in the range (low speed region) of the analog speed command voltage in which the stability of the servo motor 7 is particularly required from -2 V to 0 +2 V. 0.78 as an approximate value of 512 LSB
1r / m / LSB is obtained. The control resolution in the low speed region is 2000 r / m / 2048, which is the control resolution when a 12-bit A / D converter is used in the conventional device.
This is a value improved from the approximate value of LSB, 0.977 r / m / LSB.

Explaining the second characteristic, the values of the membership functions H and L are predetermined in a region near the analog speed command voltage of -2V and + 2V in FIG. 3 (that is, a boundary region between high speed and low speed). It is arranged to gradually change between 1 and 0 according to the inclined straight line. Therefore, equation (4)
V _ref calculated by means of membership functions H and L
Depending on the value of, for example, (1) when H = 1 and L = 0,
The value of V _ref1 becomes V _{ref as} it is, and (2) H = 0.
9. When L = 0.1, the sum of 90% of the value of V _ref1 and 10% of the value of V _ref2 is V _ref , and (3) H = 0.5, L
= 0.5, ₅₀ % of the value of V _ref1 and 5 of the value of V _ref2
The sum of the _divisions is V _ref , and: (4) H = 0.2, L =
When 0.8, the sum of 20% of the value of V _ref1 and 80% of the value of V _ref2 becomes V _ref . (5) When H = 0 and L = 1, the value of V _ref2 remains unchanged. It becomes V _ref .

Therefore, unlike the conventional method, the use of one control characteristic is not suddenly stopped at the boundary point of two different control characteristics, and the control characteristic is switched to the use of the other control characteristic at the same time. A region where control characteristics are used together is provided, and the membership function value to which one control characteristic is applied is gradually decreased, while at the same time the membership function value to which the other control characteristic is applied is gradually increased to make a transition. Since this is done, no discontinuity or step is generated in the boundary region between the high speed and the low speed, and a smooth connection as shown by the broken line in FIG. 4 is possible.

The input gain setting device 3 shown in FIG.
Since only the offset value correction operation is performed on the converted data, this operation operation is performed by the fuzzy reasoner 13
Remove the input gain setter 3 as shown in
The output of the / D converter 2 may be directly supplied to the fuzzy reasoner 13.

Example 2. FIG. 5 is a configuration block diagram of a speed command input unit according to the second embodiment of the present invention. 1a to 1e are # 1 to # 5 analog circuits, and 12A is # 1 to # 5.
A selector which sequentially selects the outputs of the analog circuits 1a to 1e and supplies them to the A / D converter 2, and 13A is a fuzzy reasoner which also includes the offset value correction function of the input gain setting device 3 of FIG. .. Further, 11A is a speed command input unit according to the second embodiment.

FIG. 6 is a signal conversion characteristic diagram of the # 1 to # 3 analog circuits 1a to 1c shown in FIG. 5, and FIG. 7 is a signal conversion characteristic of the # 4 and # 5 analog circuits 1d and 1e shown in FIG. FIG. However, the vertical axis in FIGS. 6 and 7 is shown as an A / D conversion output obtained by quantizing the output of each analog circuit through the A / D converter 2. 6A has the same signal conversion characteristic as that of FIG. 2A and linearly converts the entire range of the analog speed command voltage from -10V to 0 to + 10V. (B) and (c) of FIG. 7 and (a) and (b) of FIG. 7 are linear partial regions mainly for high speed, middle low speed and reverse rotation middle low speed and high speed of forward rotation at the speed command voltage, respectively. Is to be converted to. FIG. 8 is FIG.
FIG. 13B is an explanatory diagram of a membership function in the fuzzy reasoner 13A of FIG.
P and HP correspond to the signal conversion characteristics of (b) and (a) of FIG. 7 and (c) and (b) of FIG. 6, respectively.

The operation of FIG. 5 will be described with reference to FIGS. Now analog speed command voltage -10V ~ 0 + 10V
Is commonly supplied to the # 1 to # 5 analog circuits 1a to 1e.
Signal conversion is performed according to the signal conversion characteristics shown in (b), (c), and (a), (b) of FIG. Selector 12A
Selects the output of each analog circuit in sequence and A / D converter 2
Supply to. The A / D converter 2 outputs quantized digital data V _a , V _b , V _c , V _d and V _e , respectively, and supplies them to the fuzzy reasoner 13A.

The fuzzy reasoner 13A performs the following fuzzy operation. (1) The speed command data V _ref1 based on if V _a = HP then, V _b is calculated from the following equation (6).

[0049]

[Equation 6]

(2) if V _a = LP then, V _c
The speed command data V _ref2 based on is calculated from the following equation (7).

[0051]

[Equation 7]

(3) if V _a = LN then, V _d
The speed command data V _ref3 based on the above equation is calculated from the following equation (8).

[0053]

[Equation 8]

(4) if V _a = HN then, V _e
The speed command data V _ref4 based on the above equation is calculated from the following equation (9).

[0055]

[Equation 9]

In the above equations (6) to (9), FIG.
As in the case of, the comparison coefficient 6 is set in the first term so that the speed command data corresponding to the rotation speed of 2000 r / m becomes 2048.
14.4 / 512 = 1.2 multiplication and offset correction value addition in the second term.

(5) Next, from the speed command data V _{ref1 to} V _ref4 based on the calculated V _{b to} V _e and the corresponding membership functions HP, LP, LN and HN, the following equation ( A single speed command data V _ref is obtained by performing a synthetic operation by fuzzy inference according to 10).

[0058]

[Equation 10]

By using the speed command data V _ref obtained as a result of the synthetic operation processing by the fuzzy inference as described above, the control resolution is 1200 r / m / 1024 LSB even if a 10-bit A / D converter is used. Approximately 1.17r / m / LSB, which is almost 12 bits of A
A high resolution equivalent to that of a / D converter can be obtained, and a smooth connection can be achieved without causing discontinuity or step in the connection region of each control characteristic.

In FIG. 5, the selectors 12A and A /
An example in which the device is separate from the D converter 2 has been shown.
Since a single element called an A / D converter with a multiplexer is currently commercially available as a selector and quantizer, it can be used to reduce the number of constituent elements.

The synthetic operation processing based on fuzzy inference according to the present invention is not necessarily limited to the equation (4) or the equation (10) shown in the first or second embodiment, and other synthetic operation by fuzzy inference. May be performed. In this case, the characteristic of the connection curve in the connection area of each control characteristic divided into a plurality changes due to the difference of the synthetic arithmetic expression, and the fuzzy inference synthetic arithmetic expression that can obtain the connection curve with the desired characteristic is adopted. It should be done.

[0062]

As described above, according to the present invention, a plurality of analog circuits commonly input a speed command voltage signal for instructing the rotation speed of the servo motor according to the polarity and voltage value of the analog voltage. Signal conversion is performed by voltage amplification with different gains and addition of different offset voltages, and the selecting and quantizing means sequentially selects a plurality of converted signals output from the plurality of analog circuits, The selection signal is sequentially converted into digital data, and the fuzzy inference means performs a synthetic operation process by fuzzy inference on a plurality of digital data sequentially output from the selection and quantization means to obtain a single speed command data. As a result, high-resolution control characteristics can be obtained in each of the divided control areas, and the connection of each control characteristic can be achieved. Discontinuities or steps in the area becomes possible smooth connection without occurrence.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a servo motor control device according to a first embodiment of the present invention.

FIG. 2 is a signal conversion characteristic diagram of the two analog circuits shown in FIG.

3 is an explanatory diagram of a membership function in the fuzzy reasoner of FIG.

FIG. 4 is a connection explanatory diagram of different speed control characteristics according to the first embodiment of the present invention.

FIG. 5 is a configuration block diagram of a speed command input unit according to a second embodiment of the present invention.

6 is a signal conversion characteristic diagram of the # 1 to # 3 analog circuits shown in FIG.

7 is a signal conversion characteristic diagram of the # 4 and # 5 analog circuits shown in FIG.

8 is an explanatory diagram of a membership function in the fuzzy reasoner of FIG.

FIG. 9 is a configuration block diagram of a conventional general servo motor control device.

10 is a conversion characteristic diagram of an input voltage and output data of the A / D converter in FIG.

FIG. 11 is a configuration block diagram of a drive control device for a motor disclosed in a known document.

[Explanation of symbols]

 1, 1a to 1e Analog circuit 2 A / D converter 3 Input gain setting device 4 Speed control amplifier 5 Current control amplifier 6 Current detector 7 Servo motor 8 Encoder 9 Differentiator 10a, 10b Subtractor 11, 11A, 11B Speed command Input unit 12,12A selector 13,13A fuzzy reasoner

Claims (1)

[Claims] 1. A speed command voltage signal for commanding the rotation speed of a servo motor according to the polarity and voltage value of an analog voltage is commonly input, and voltage amplification by different gains and addition of different offset voltages are applied to the input signal. A plurality of analog circuits for performing signal conversion by means of, and a selecting and quantizing means for sequentially selecting a plurality of converted signals respectively output from the plurality of analog circuits and sequentially converting the selected signals into digital data, A servo motor control device, comprising: fuzzy inference means for performing a synthetic operation process by fuzzy inference on a plurality of digital data sequentially output from the selecting and quantizing means to obtain a single speed command data.