JPS6278614A - Servo amplifier - 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] [Industrial Application Field] The present invention relates to a servo amplifier for controlling the drive speed of an actuator to a predetermined speed, and more specifically, to a servo amplifier for controlling the drive speed of an actuator to a predetermined speed. The present invention relates to a servo amplifier including a speed control means for feedback controlling the drive speed of an actuator based on a comparison result with a speed command value.

[Conventional technology]

This type of servo amplifier described above performs feedback control of the drive speed of the actuator by modulating the power supply voltage to the actuator, such as the motor, using the PWM method based on the deviation between the speed command value and the detected speed.・
It is structured as follows.

Conventionally, the servo amplifier described in - has been configured with an analog circuit, and when controlling the operation of the servo amplifier with this analog circuit configuration, for example, as shown in FIG. 8, an actuator ( The main processor (a) commands information such as the target stop position and driving direction of the
) and a counter (f) that counts the stop position command value (Xl) given from the encoder (e) and its output pulse number.
), the servo processor (b) calculates the drive speed command value (ω*) of the actuator (M), and the speed command value (ω*) is transferred to the D/A.
The converter (c) converts it into an analog voltage, and the deviation (ε) from the speed (ω) detected by the speed detection means (d) such as a tacho generator is calculated in analog form. Based on the deviation (ε), the servo amplifier ( g) was configured to modulate the voltage supplied to the actuator (formerly) using the PWM method. As a means for modulating the voltage supplied to the actuator (M) using the PWM method, for example, the analog calculation described above can be used. By comparing the value of the deviation (ε) thus obtained with a triangular wave oscillated at a predetermined period using a comparator or the like, a pulse width modulated PWM wave is obtained.

[Problem that the invention seeks to solve]

However, in the conventional servo amplifiers mentioned above, the power supply for adjusting the drive speed of the actuator is controlled by a device configuration using an analog circuit, so there are many adjustment parts and there are also changes in the temperature of the usage environment and changes over time. It is desirable to digitize this servo amplifier because it is susceptible to the effects of However, the disadvantage is that the device configuration is complicated and expensive.

Therefore, the hardware of the entire servo amplifier is configured by providing digitalized hardware for parts that need to be provided as hardware, such as power control, and by configuring arithmetic functions that can be realized with software using a microcomputer. However, in this case, the calculation of the deviation between the command value and the detected value may involve four arithmetic operations on real numbers (for example, floating point operations), and in a small general-purpose microcomputer, The calculation execution speed is a problem, and there is a disadvantage that a control response as a servo amplifier that requires real-time processing cannot be obtained.

One way to improve the execution speed of the above calculations is to calculate the deviation between the command value and the detected value in advance and create a table of that value.In this case, in order to maintain control accuracy, it is necessary to This has the disadvantage that the memory capacity for storing the converted deviation values becomes large, and the device configuration cannot be simplified.

The present invention has been made in view of the above-mentioned circumstances, and has the object of simplifying the device configuration when digitizing a servo amplifier while not slowing down its processing speed.

[Means for solving problems]

The characteristic configuration of the servo amplifier according to the present invention includes: a deviation calculating means for converting the deviation between the speed command value and the detected speed into an integer and calculating it; a PWM wave generating means for generating a PWM wave corresponding to the deviation; and a PWM wave generating means for generating a PWM wave corresponding to the deviation. Output PWM from generation means
Each of the power amplifiers is provided to amplify the power of the wave and drive the actuator, and the functions and effects thereof are as follows.

[For production]

That is, by calculating the deviation between the speed command value and the detected speed by converting it into an integer, the calculation of the deviation can be performed by simple addition/subtraction processing of integers. Then, a PWM wave corresponding to the determined deviation is generated, the power of the PWM wave is amplified, and the power is supplied to the actuator, thereby controlling its driving speed.

〔Effect of the invention〕

In other words, since the deviation calculation between the command value and the detected value is executed as a simple addition/subtraction process of integer values, for example, even if this deviation calculation means is configured using a general-purpose microcomputer, the calculation execution speed will be a problem. It will never be. Further, the calculated deviation is also an integer value, and the means for generating a PWM wave corresponding to the calculated deviation can be realized as a small-scale digital circuit such as a timer or a counter. Therefore, the power amplifier that drives the actuator is
It is sufficient to provide the function of simply power amplifying the waves, and the overall configuration of the servo amplifier can be simplified without slowing down its processing speed.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing the overall configuration of a servo amplifier, and includes an incremental encoder (1) that detects rotational speed and position information in conjunction with the rotation of a servo motor (M) as an actuator, and this encoder. (1
) to calculate the current position information of the controlled device (not shown) driven by the motor (M), that is, the detected position f
A counter (2) that outputs the value of f(X), an F/V converter (3) that converts the output frequency, that is, the driving speed, of the encoder (1) into a voltage, and this F/V converter (3).
A gain adjuster (4
), an A/D converter (5) that converts the voltage corresponding to the detected speed (ω) outputted through the gain adjuster (4) into a digital value and outputs the detected speed (ω) as an integer.
, the detected position (X) from the counter (2) and the target stop position given from the main processor (6)! (X”
), the command value (ω*) of the drive speed of the motor (M) is calculated, and the speed command value (ω”)
A servo processor (7) that calculates the deviation (ε) between the detected speed (ω) and the detected speed (ω), a programmable timer (8) as a PWM wave generation means that generates a PWM wave corresponding to the deviation (ε), and this programmable A power amplifier (9) is provided which amplifies the power of the PWM wave generated by the timer (8) and drives the motor (M). Thus, the encoder (1) and the counter (2) constitute a position detecting means, and the encoder (1) and the F/V converter (3) constitute a position detecting means.
) constitutes a speed detection means (100), and the gain adjuster (4) and A/D converter (5) constitute a detected speed integer conversion means.

By the way, the gain adjuster (4) originally
This is necessary to A/D convert the output of the V converter (3) so that the speed command value (ω") and the detected speed (ω) are on the same scale, and this function can be used as is. Since the detected speed (ω) is converted into an integer, the device configuration does not become complicated.

Next, the basic operation of the servo amplifier having the above configuration will be explained based on the block diagram shown in FIG.

That is, in the speed command value calculation unit (7a) of the servo processor (7), which serves as a speed command means that commands the speed command value (ω*') as an integer value, the target stop given from the main processor (6) is determined. position (X'″) and
Based on the detection position (X) output from the counter (2), the command value (
ω*) is the period (TI) of the PWM wave (V) output from the programmable timer (8) and its pulse width (T
2), the drive voltage (V9) with respect to the rated voltage (VR) of the motor (M) and its rotational speed (ω)
) is converted into an integer based on the following equation (i).

VR 0 house - 1・T, (6)") ...... (i) ν4 On the other hand, the detected speed (ω) of the motor (M) is determined by the encoder (1) and F゛/V/V It is detected as a voltage value by the converter, and the rated voltage (ν) and rated rotational speed (ω
The duty ratio of the output PWM wave (V) from the programmable timer (8) is converted into a function of the actual drive voltage (Vf) and rotational speed (ω) based on the relationship between the A signal of an integer value corresponding to the ratio (h/TI), that is, a command speed (
It is adjusted to have a value on the same scale as ω*'), and is digitized by the A/D converter (5).

Then, the deviation calculation section (7) of the servo processor (7)
In b), the deviation (ε) is calculated by adding and subtracting the integer command speed (ω1) and the detected speed (ω) as integers, and the gain setting unit (7c) calculates the deviation (ε). Acceleration gain (Kp) (However, in this example, Kp・1)
The occurrence P in the programmable timer (8) is multiplied by
The generated pulse width of the PWM wave (V) is set so that the duty ratio (Tz/y+) of the WM wave (V) corresponds to the power supplied to rotate the motor (M) at the command speed (ω*). (TE10) and the motor drive voltage (ν). Therefore, the programmable timer (TE10) is determined as a function of the motor drive voltage (ν).
8> is P of a predetermined pulse width (T214) corresponding to the deviation (ε) outputted via the gain setting section (7c).
A WM wave (V) is generated, and the power amplifier (9) generates a generated PWM wave (V) determined from the relationship between the drive voltage (V8) and rotational speed (ωR) of the motor (M). The power is amplified to become driving power.

In other words, both the speed command value (ω") and the detected speed (ω) are given as integer values, and the deviation (ε) is the PWM wave (V) output from the programmable timer (8).
By converting the servo processor (7) into an integer corresponding to the duty ratio, that is, the generated pulse width (T2M),
This makes it possible to simplify the device configuration while making the processing speed practical.

Hereinafter, the operation of the servo amplifier having the above configuration will be described in detail based on the flowcharts shown in FIGS. 3 to 5.

That is, as shown in FIG. 3, the speed command value calculation section (7a) of the servo processor (7) calculates the detected position (X) with respect to the target stop position (X'') given from the main processor (6). The deviation is calculated, and the speed command value (ω*) is calculated based on the position deviation (ε).

As shown in FIG. 4, the positional deviation (εX) is determined by reading the count value of the number of output pulses from the encoder (1) counted by the counter (2), that is, the detected position (X), and by reading the detected position (X) by the main processor ( 6) Target position i from
'! It is obtained by reading (X″') and calculating its deviation (εX).

Then, as shown in FIG. 5, based on the calculated positional deviation (εX), the speed command value (ω*) is calculated as an integer value U2. In other words, check whether the movement flag indicating whether or not the motor (M) is being driven is set to "1" (step #1); if it is not set to "1", then , the state of the rule flag indicating whether the speed control method is a normal proportional control method or a square root method, which will be described in detail later, is checked (step #2).

The movement flag checked in step #1 above is “1”
If the acceleration gain (Kp) is set in advance, the acceleration gain (Kp) is set to a predetermined value (step #3).
, set the root flag to 1″ (step #4
), it is checked whether the detected position (X) has reached the target stop position (X'') (step #5).

Then, when the detected position (X) has reached the target stop position (X''), the movement flag is reset to "0" (
Step #6).

The root flag checked in step #2 above is 1.
”, the acceleration gain (Kp
) to the predetermined gain at servo lock step #
7), the speed command value (ω*) is converted to the position deviation (εX)
is updated to a value obtained by multiplying by the acceleration gain (Kp) (step #8).

On the other hand, if the route flag is set to "1", check whether the detected position (X) approaches the target stopping position (X'') within a predetermined deviation or not.Step #9 ), the deviation (ε, ) of the position is the set value (A)
If the acceleration gain (Kp) is below, the acceleration gain (Kp) is changed to the normal proportional control method so as to stop smoothly.
to the set deceleration gain in the proportional control method (step #10), and reset the route flag to "O" (step #10).
Step #11).

If the detected position (X) checked in step #9 is more than a predetermined deviation (A) from the target stop position (X'''), the pulse width (T) of the PWM wave (V) engineering)
is proportional to the square root (8-) of the positional deviation (ε8), the pulse width (TZ) is set based on the following formula (i), and speed control is performed by the square root method (step # 12).Therefore, the above-mentioned steps
At t12, the deviation calculation means (7h) is configured.

7,,ocωI-・hdirectJ″vx) ・= −(ii
) In other words, in a region where the target stopping position (X") G and the pair of position deviations (ε) are large, speed control is performed using the square root method 6.'2 using a control gain proportional to the square root (,5'-) of the pair of position deviations (ε). Then, with a small control gain, L] mark stop position i(x”
) position, and the detected position is 11W (X
) is close to the target stop position (X''), the control is switched to the normal proportional control method to maintain the control gain appropriately, thereby stabilizing the control.

[Another example]

In the above embodiment, the case where the speed command value (ω*) is converted into an integer is calculated in the servo processor (7) is illustrated, but the main processor (6)
It is also possible to convert it into an integer in advance and give it. Furthermore,
As shown in FIG. 6, the function of the gain adjuster (4) is provided in the servo processor (7) as a gain adjustment section (4a), and the deviation ( ε) without converting it into an integer and directly converting it to the servo processor (7
) is calculated by the deviation calculation unit (7b) of the motor (M
), the motor drive voltage (VW) corresponding to the deviation (ε), the period (Tt) of the PWM wave (V), and the pulse width (Tt) corresponding to the motor drive voltage (V).
The gain g may be set to an integer based on the standard deviation (6M) that gives z, 4).

Further, as shown in FIG. 7, similarly to the other embodiment illustrated in FIG.
7) The rated voltage (VR) of the motor 01)
, the motor drive voltage (VW) corresponding to the deviation (ε), and the period (T1) of the PWM wave (ν), calculate the pulse width (T□) with the gain adjusted, and Then, the calculated pulse width (T0n)
The PWM wave (v) may be generated so that the supplied power corresponds to the .

In addition, 1.- In each of the above embodiments, the servo processor (
7), the acceleration gain (K
The case where the IQ is set is shown as an example, but this gain (
Hp) may be any other value. In this case, if the gain (Kp) is set to an exponent times 2 so that it becomes Kp·21, the arithmetic processing of the gain setting by the microcomputer can be performed at high speed by using an internal register shift command or the like.

Further, in the above embodiment, the speed detecting means is constituted by the encoder (1) and the F/V converter (3), but for example, other types of speed detecting means such as a tacho generator may be used. Good too.

[Brief explanation of drawings]

1 to 7 show embodiments of the servo amplifier according to the present invention, FIG. 1 is a block diagram showing the overall configuration of the servo amplifier, FIG. 2 is a block diagram showing its functions, and FIGS. FIG. 5 is a flowchart showing the operation of the servo processor;
FIGS. 6 and 7 are block diagrams showing the configuration of another embodiment. FIG. 8 is a block diagram showing the configuration of a conventional example. (7b)... Deviation calculation means, (8)...
・PWM wave generation means, (9)...power amplifier,
(200)...Speed detection means, (M)...
...actuator, (V) ...PWM wave,
(ω)...Detected speed, (ω")...Speed command value, (ε)...Deviation.

Claims (1)

[Claims] A servo amplifier equipped with a speed control means for feedback controlling the drive speed of the actuator (M) based on a comparison result between the speed (ω) detected by the speed detection means (100) and the given speed command value (ω^*). a deviation calculating means (7b) for converting the deviation (ε) between the speed command value (ω^*) and the detected speed (ω) into an integer and calculating the deviation (ε);
), and an output P of the PWM wave generating means (8).
The actuator (M) is powered by amplifying the power of the WM wave (V).
and a power amplifier (9) for driving the servo amplifier.