JPS6364587A - Motor speed controller - Google Patents

Abstract

PURPOSE:To exactly control a speed, by computing a time till data are read in a microcomputer after the data are produced at a latch, and by correcting a speed feedback value. CONSTITUTION:When the data of a first latch 28 are read by a micro-computer 29, then a second latch 32 holding the data of a first counter 22 and a second counter 33 is set. In the microcomputer 29, the values of the counters 22, 33 when the data of the first latch 28 are read are read. As a result, a time till the data of the first and second counters 22, 33 are read in the microcomputer 29 after the data are held at the first latch 28 with the rise of the output of a comparator 27 is computed, and a speed feedback value is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a motor speed control device used in industrial robots and NC machine tools.Background ArtIn recent years, motor control devices have been used in industrial robots and NC machine tools. As seen in the trajectory control of More reliable and resistant to adverse conditions, such as magnetic encoders and magnetic encoders, are required.

An example of the conventional motor speed control device mentioned above will be described below with reference to the drawings.

FIG. 3 shows the configuration of a conventional motor speed control device. In Figure 3, 1 is an oscillator that generates a clock pulse of 5 M) (z), 2 is a 10 bit counter that counts up to 0 or 1023, and 3 is a read-only memory (hereinafter referred to as ROM) into which the data shown in Figure 4 is written. ),
4 is a D/A converter, 5 is an amplifier composed of an operational amplifier and a power transistor, 6 is two windings on the excitation side,
The output side VC has one winding, and as shown in FIG. 5, two sine wave voltages a with a phase of 90 degrees are stacked on the excitation side.

When b is applied, the resolver outputs a sine wave voltage C whose phase is delayed from the rotation angle θ from the reference position and the voltage a. 7 is "H" if the output voltage of the resolver 6 is 07 or more, and "L" if it is OV or less. A comparator that outputs the level as shown in FIG. A driver 11 is a motor that causes a current corresponding to the output to flow through the motor.

The operation of the motor control device configured as described above will be explained below.

First, the 5MHz clock pulse generated by oscillator 1 is 1
It is counted by counter 2 with 0 bit.

When this counter reaches the maximum value of 1023, it starts counting again from 0. The 10-pin output of the counter 2 is converted into two 8-pin sine wave data according to the table shown in FIG. 4 written in the ROM 3, and converted into an analog signal by the D/A converter 4. The output of the D/A converter 4 at this time becomes two sine wave voltages with a phase difference of 90 degrees.

These two sine wave voltages are amplified by an amplifier 5 and a resolver 6
is applied to the two excitation windings. If the excitation voltage at this time is shown as a, b in FIG. 5, the output of the resolver 6 will be a rotation angle θ from the reference position, as shown in FIG. 5C, which is delayed in phase from a in FIG. 5a. The output of the resolver 6 is compared by a comparator 7 and converted into a digital signal as shown in FIG. 5d. At the rising edge of this signal, the latch 8 holds the data of the counter 2, and the microcomputer 9 reads it every 1 m5eC. This value represents the position when one rotation of the motor 11 is divided into 1024 equal parts, and the speed feedback value can be obtained by taking the difference between the value read this time and the value read last time. According to the flowchart shown in FIG. 6, the microcomputer a reads the 10 bit data of the ratte 8 in step 1, and in step 2 the data is sent from the host computer or stored in the memory of the microcomputer 9.
Obtain the speed command value. In step 3, the value read from the latch 8 last time and stored in the memo 1 is subtracted from the value of the latch 8 read this time to obtain the speed feed bank value.

If the value of the latch 8 changes from 0 to 1023 at this time, it means that the pulse has moved by 1023 pulses, although in reality it has only moved by 11 pulses. So 1 m5e
Time of C (maximum pulse 5 to move C) When motor speed is 3000 ram, 3000 (rpm) x 1024 (pulse) xo, ool
(sec)/6o(sec)=51.2(pulse 7'm
Equation) A value υ greater than this value, for example, 60 pulses, is set as the maximum pulse deviation, and if it is greater than this value, 1024 is added to the previous value and step 3 is repeated again.

If the velocity feedback value is positive in step 4, it is compared with 60 pulses in step 5, and if it is 60 pulses or more, 1024 is added to the previous velocity feedback value in step 6, and the velocity feedback value is returned to step 3. If is negative, compare with -eO pulse at the end of the step, and if less than 16 o pulses, subtract 1024 from the previous speed feedback value in step 8 and perform step 3 again. At step 9, the speed feedback value is subtracted from the speed command value to obtain the speed error value. At step 10, this speed error value is multiplied by V, the constant stored in the memory, and 1, and the speed error value. The sum of the cumulative value from the start and the same constant multiplied by 2 is calculated and used as the current command value. Step 11 is a wait timer set so that the program is executed at least once every 1 m5ec, and step 12 outputs a current command value to the driver 1C to rotate the motor 11.

Problems to be Solved by the Invention However, in the above configuration, the data in the latch 8 is transferred to the microcomputer 9 at the timing shown in FIG. 5e.
The data read by is the data when the output signal of the comparator 7 rises, and a time delay td occurs during this time. Now, the time delay when reading the data last time is t
d(n-1), and the current time delay is td(n), then 2
The interval between two data is td(n-1) td for one equation.
(n) and as a result, the speed feed puncture value also has an error, resulting in the problem that speed control cannot be performed accurately.

In view of the above-mentioned problems, the present invention provides a motor speed control system that enables accurate speed control by calculating the time from when the data of the counter 2 is latched to the latch 8 until it is read into the microcomputer and correcting the speed feedback value. A control device is provided.

Means for Solving the Problems In order to solve the above problems, in the motor speed control device of the present invention, a second counter is provided above the first counter, and when the comparator rises, the first counter and the second The data of both the counters are held in the first latch means, and when the microcomputer reads the data of the first latch means, the data of both the first counter and the second counter are held in the second latch means. It has a structure in which it is held by a latch means and read into a microcomputer.

Function The present invention has the above-described configuration, so that the first latch means
．． The above td is obtained by measuring the time from when the data of the second counter is held to when the microcomputer goes to read the data of the first latch means using the second latch means. By correcting the speed feedback value based on the value, an accurate speed feedback value can be obtained and the speed controllability of the motor can be improved.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a motor control device in an embodiment of the present invention. In Figure 1, 21 is 5M
22 is a 10 pit counter (first counter), 23 is a ROM 124 in which the data shown in FIG. 4 is written, is a D/A converter, 25 is an amplifier, 26 is a resolver, 2"i' 28 is the first latch, 29 is the microcomputer, 3o is the driver, and 31 is the motor.
These are the same as the configurations 1 to 11 of the conventional example shown in the figure. 32, the microcomputer 29 connects the first latch 28
A second latch holds the data of the first counter 22 when the data is read and sends it to the microcomputer 29. 33 is a latch connected to the most significant carry signal of the first counter 22. Bit counter (second counter)
It is.

The operation of the motor speed control device configured as described above will be explained below with reference to FIGS. 1 and 2.

First, a 5 MHz clock pulse generated by an oscillator 21 is counted by a first counter 22, and converted into two pieces of 8-bit data in a ROM 23 according to a table as shown in FIG. This 8-pit data is converted into analog data by a D/A converter 24, amplified by an amplifier 25, and sent to a resolver 2.
6 is excited. One force of resolver 26 is comparator 2
7, it is compared with Ov (reference voltage) and digitized. At the rising edge of this signal, the data of the first counter 22 and the second counter 33 are held in the first latch 28. The microcomputer 29 reads the contents of the first latch 28 every 1 mSec. At this time, the first counter 22
and the data of the second counter 33 to the second C'') latch 32
The microcomputer 29 then reads the data. The processing content of the microcomputer 29 is the same as that shown in FIG. 6, and before 6 calculates the speed error value in step 9, a speed correction program is executed. This flowchart is shown in FIG. In step 21 of FIG. 2, 11 pit data of the second latch 32 is first read. 1 of the first counter 22 of the data read in step 21
The value corresponding to 0 bit is DAl, the value of 1 pit corresponding to the second counter 33 is DA2, and the first latch 28
Of the 11-bit data, the value corresponding to 10 bits of the first counter 22 is DB1, and the value of 1 pint corresponding to the second counter 33 is DB2.
2 and DB2 are compared, and if n is not equal, the corrected pulse number Pn is set to P -1024+DA1-DB1 in step 23. If DA2 and DB2 are equal in step 22, DAl and DB1 are compared in step 24.

When DA1≧DB1, the corrected pulse number Pn P =DA1-DB1 is set in step 25. Further, when DA1 is smaller than DB1 in step 24, the number of corrected pulses Pn P =2048+DA1-DB1 is set in step 26. In step 27, the speed feedback value is corrected as follows from Pn obtained by the above method and Pn-1 previously obtained and stored in the memory.

Thereafter, the current command value is determined using the corrected psychokinetic feedback value and outputted to the driver 30 to rotate the motor 31 in the same manner as in the conventional method.

As described above, according to this embodiment, when the microcomputer 29 reads the data of the first latch 28, the second counter 22 and the second counter 33 hold the data of the first counter 22 and the second counter 33. 32 is provided, and the microcomputer 2
9 reads the value, and sets the first latch 28 to the first latch 28. By calculating the time from when the data of the second counters 22 and 33 are held at the rising edge of the output of the comparator 27 until the data is sent to the microcomputer 29 and correcting the speed feed bank value, positive (16 speed control is performed) be able to.

Effects of the Invention As described above, the present invention provides a motor speed control device that uses a resolver as a detector and a microcomputer for ia+j control calculations. A second latch means for holding the data of the second counter is provided, and the data is stored in the first latch by causing the microcomputer to read the counter value when the data of the first latch means is read. Accurate speed control can be performed by calculating the time it takes for the sword to be created and read into the microcomputer and correcting the speed feed bank value.

[Brief explanation of the drawing]

Figure 1 shows one embodiment of the present invention divided into motor speeds 1/1]
Fig. 2 is a flowchart for correcting the speed feedback value in the microphone computer program in C); Fig. 3 is a groove bottom diagram of a conventional motor speed control device; Figure 4 is a graph showing the contents of the ROM that converts the output data of the counter into two sine wave data, Figure 5 is a timing chart showing the input/output waveform of the resolver, the output of the comparator, and the read signal of the microcomputer. is a flowchart of a microcomputer program in a conventional example. 21...Oscillator, 22...First counter, 23...ROM124...D/A
Converter, 25...Additional 1f1m device, 26...
... Resolver, 27 ... Comparator, 28
...First latch, 29...Microcomputer, 30...Driver, 31...Motor, 32...Second latch, 33...・・・
Second counter. Name of agent Patent attorney Toshi Nakao and 1 other person Shi-de 28-Izuyuu, + 29--M17Ill controller 3o--B-rai, (-31-'-7 Figure 4 entry CfQ and 'tsugen (ha ex) 〕〕〖〖　　　　　　　　　　　　　　　　　　　　　　　　　　　　Figure 5

Claims (1)

[Claims] A motor, a resolver connected to the rotating shaft of this motor, an oscillator that generates pulses of a constant period, a first counter that counts the output pulses of this oscillator, and converts the output data of this first counter. A data conversion means and a D/A that converts the output of the data conversion means into an analog signal.
a converter, an amplifier that amplifies the output of the D/A converter and causes a current to flow through the excitation winding of the resolver, a comparator that compares the output voltage of the resolver with a reference voltage, and a a first latch means for holding the data of the counter; a microcomputer that reads the data of the first latch means, performs arithmetic operations, and outputs the result; and a driver that controls the current flowing from the output of the microcomputer to the motor. a second counter provided above the first counter; and a second latching means that receives data from the second counter and the first counter based on an output signal from the comparator. a second latch means for holding the outputs of the first counter and the second counter when the microcomputer reads the data of the first latch means; A motor speed control device characterized by being read.