JP2000139099A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a motor controller capable of sufficiently controlling change of acceleration with small operation error while using a simple operation expression. SOLUTION: By using a simple recurrence formula Ri=Ri-1+αu/Ri-1, where Ri is the i-th velocity and αu is the gradient of a line (acceleration), a velocity pattern composed of a plurality of lines is operated. At an acceleration change point, the acceleration αu which is to be substituted in the recurrence formula is made the acceleration (αu+1 of the next line or the acceleration (αu-1 of a precedent line, thereby restraining the change of acceleration. Further operation error is estimated, and the αu value is corrected and substituted in the formula. From an acceleration (gradient) and a velocity range, the error direction/quantity of the formula is previously studied, and correction is performed from the command range. When the operation result becomes higher than or equal to a high speed constant velocity command value or lower than or equal to a low speed constant velocity command value, correction is performed by preventing the velocity from exceeding the command value on account of accumulation of operation errors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motor control device controlled by a pulse calculation.

[0002]

2. Description of the Related Art Pulse motors (stepping motors)
Is driven by a pulse signal generated from a pulse generator, and rotates by an angle corresponding to the number of pulses of the pulse signal at a rotation speed corresponding to the frequency of the pulse signal. Therefore, in order to control the speed of the pulse motor, it is necessary to control the frequency and the number of pulses of the pulse signal. Further, as in the DC / AC servomotor pack, it is necessary to control the pulse signal for speed control by inputting the pulse signal.

Usually, in a pulse motor, as shown in FIG. 14, speed control with respect to time is set to trapezoidal control.
In other words, when the pulse motor is started, the frequency of the pulse signal is gradually increased to gradually increase the rotation speed. When the rotation speed of the pulse motor reaches a predetermined speed, the frequency of the pulse signal is fixed to keep the rotation speed constant. When the pulse motor is stopped, the frequency of the pulse signal is gradually decreased to gradually decrease the rotation speed. As an example of this operation,
There is a simple calculation as disclosed in Japanese Patent Application Laid-Open No. 7-163195, and speed control can be performed by the simple calculation.

In order to change a pulse signal into various acceleration / deceleration patterns, an acceleration / deceleration pulse generator using a pattern memory for storing acceleration / deceleration pattern data of various speed curves has been considered. This acceleration / deceleration pulse generator sequentially reads acceleration / deceleration pattern data stored in a pattern memory, converts the data into serial data by a parallel / serial conversion circuit, and outputs the serial data as a pulse signal.

A pulse motor control device using a memory for storing count value data corresponding to a pulse interval and bit data indicating whether the mode is an acceleration / deceleration mode or a constant speed mode has been considered. This pulse motor control device reads out count value data and bit data from a memory, and outputs a pulse signal from a counter based on the count value data and bit data.

On the other hand, a speed control device for a step motor using a memory that stores a frequency and the number of pulses as an acceleration / deceleration table has been considered. This speed control device has a CP
U (central processing unit) sequentially reads the frequency and pulse number stored in the memory, and generates a pulse signal by a frequency divider and a counter based on the read frequency and pulse number.

As another method of suppressing the acceleration change in the trapezoidal control, a pulse generation circuit (for example, Japanese Unexamined Patent Application Publication No. Heisei 2 No. -10672) is known.

In addition, a pulse generation circuit for changing with a curve acceleration / deceleration characteristic using a trigonometric function (SIN, COS) instead of a quadratic function pattern has been considered.

[0009]

However, in the case of speed control by the above-described simple calculation, there is a problem that a large amount of time is required for suppressing a rapid change in acceleration and suppressing vibration. In other words, if the change from the speed increase to a constant speed is abrupt, vibration occurs, so the acceleration at the speed increase must be reduced, and much time is required to reach the constant speed. .

In the method of storing the acceleration / deceleration pattern data in a memory, the required memory capacity increases as the acceleration / deceleration pattern increases. However, there is a limit to the amount of the acceleration / deceleration pattern to be stored, so that it is impossible to cope with an increase in the acceleration / deceleration pattern.
Of course, it is impossible to cope with an increase in the number of pulses due to long-distance movement.

The method using the two-dimensional function pattern and the trigonometric function is complicated and time-consuming,
There is a problem that it becomes difficult to appropriately respond to high-speed operation. Further, if a slow operation at low speed is not required, if a complicated operation is performed, the operation time is increased and the throughput of the entire system may be reduced.

Therefore, it is necessary to improve the response at high speed and to reduce the size of the hardware by adopting a simple operation method without using the memory access reference method. However, according to the simple method, a calculation error may occur.
It is desirable to reduce the load on the device.

In addition to this, it is necessary to reduce the waiting time until the systematic vibration stops by suppressing the change in acceleration. However, the change in the acceleration varies depending on the size of the system or the like, so that it is desirable that the change can be selected for each system without unnecessary low acceleration change.

An object of the present invention is to realize a motor control device which uses a simple calculation formula, has a small calculation error, and can sufficiently suppress a change in acceleration.

[0015]

In order to achieve the above object, the present invention is configured as follows. (1) The operation of a control pulse calculation unit for calculating a control pulse signal to be output to a motor, the phase output calculation unit for calculating the phase output of a control pulse output to a motor, and the operations of the control pulse calculation unit and the phase output calculation unit A motor control device having a control unit for controlling a speed line composed of a period and an acceleration by a predetermined simple calculation, and a control calculation unit for calculating a motor speed pattern by combining the calculated plurality of speed lines. And a control operation unit that suppresses a change in acceleration at a connection portion between adjacent speed straight lines.

A speed pattern is calculated by combining a plurality of speed straight lines calculated by a simple calculation formula, and a change in acceleration at a connection portion between adjacent speed straight lines is suppressed, so that a complicated calculation is not performed, and Thus, the change in acceleration is suppressed.

(2) Preferably, in the above (1),
The control calculation unit sets Ri as the speed of the i-th speed straight line,
If αu is the acceleration of the i-th speed line and Ri-1 is the slope of the i-1th speed line, Ri = Ri-1 + αu / Ri
According to the recurrence formula, the speed Ri of the i-th speed straight line is
And if the period of the i-th speed straight line is ti,
The period ti of the i-th speed straight line is calculated by the equation ti = 1 / Ri.

(3) Preferably, in the above (2), the control operation unit calculates a speed Ri at a connection portion between the speed straight lines adjacent to each other, αu + 1 to an acceleration of the (i + 1) th speed straight line. Then, Ri = Ri-1 + αu + 1 / Ri-
The change in the acceleration at the connection portion between the speed lines adjacent to each other is suppressed by performing the calculation according to the formula (1).

(4) Preferably, in the above (1), a communication function for communicating control information to another motor control device is further provided.

Since the motor control device calculates the speed pattern by a simple calculation, the load for calculating the speed pattern is reduced, thereby providing a communication function. By providing the communication function, a plurality of motors can be distributedly controlled by a plurality of motor control devices.

(5) Preferably, in the above (1) to (4), the control operation unit is an LSI.

(6) Preferably, in the above (1) to (5), learning of calculating an error of the acceleration of the velocity line calculated by the control calculation unit and calculating a correction value based on the calculated error. Provide functions.

The error learning function corrects the calculation error of the speed straight line, and enables more accurate speed control.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A motor control device according to an embodiment of the present invention will be described with reference to the accompanying drawings. As an example of performing the motor acceleration / deceleration pattern by combining a plurality of straight lines (speed straight lines), a linear acceleration pattern as shown in FIG. 1 is shown. In this example, the acceleration / deceleration pattern is composed of eight straight lines including the acceleration / deceleration and the constant speed.

In FIG. 1, a straight line represents an acceleration pattern (; slow start, acceleration, acceleration landing), a high speed constant speed, and a deceleration pattern (;
Slowdown, slowdown, slowdown landing),
Plays the role of low speed constant speed.

If the trapezoidal control is represented by this method, that is, if it is represented by a plurality of linear patterns, the pattern is composed of In addition to the trapezoidal control, the eight straight lines in FIG. 1 are the above-mentioned straight lines. In addition to the straight lines, a slow start straight line effective for suppressing a change in acceleration is added before the straight line, and after the straight line, a high-speed constant speed. A straight line that is effective to suppress the change in acceleration to is added. Furthermore, after the straight line,
Add an effective straight line to smooth the start of deceleration change,
A straight line effective for suppressing the vibration before stopping is added between the straight line and the straight line.

FIG. 2 shows an example of an output waveform of a pulse signal output for controlling the speed of the motor. Pulse signal 1
In order to calculate the cycle time for each cycle, it is necessary to first calculate a speed that is the reciprocal of the cycle from the viewpoint of constantly accelerating the motor speed. As an example, the following equation (1) is shown as a recurrence equation for calculating the speed, and the following equation (2) is shown as an equation for calculating the time (period) ti. Ri = Ri-1 + αu / Ri-1 (1) ti = 1 / Ri (2) where Ri is the speed of the i-th straight line, and αu is i
The inclination (acceleration) of the second straight line.

As can be seen from the above equations (1) and (2), the next speed information (Ri-1) is obtained from the previous speed information (Ri-1).
i) can be calculated. Further, αu in the equation (1) represents acceleration, that is, a gradient of speed, and is represented by a straight line in FIG.
And have three slopes of α1, α2 and α3. Of course, the inclination α1 does not change in a straight line. Further, since the straight lines 、 and 〜 can be calculated by the same arithmetic expression (1) simply by changing the coefficient of αu, the motor control device can be reduced in size by sharing hardware. This makes the hardware LSI particularly effective.

Next, an example of an instruction method of an acceleration / deceleration pattern composed of a plurality of straight lines will be described with reference to FIG. When the portion where the motor torque is large or the object to be loaded is lightweight, the starting (starting) speed is usually started from a high speed, and a slow-up (linear portion) is unnecessary. Therefore, as an example of a command method when a straight line is not required and a straight line or later is required, a register needs to indicate whether or not it is necessary,
If "0" is unnecessary and a command value is given in a command format at the time of starting the motor, it can be selected. That is, as shown in FIG. 3, if “11111110”, the straight line is “0” and the straight line is “1”, so that a straight line is unnecessary and a straight line is necessary. . FIG. 5 shows an example of a speed pattern in which a straight line is unnecessary, a straight line, and are required.

FIG. 4 shows an example of a motor speed pattern emphasizing slow-up on the start, in contrast to the example of FIG. 3 where the start speed is high. In FIG. 4, in addition to requiring a straight line to make all of these accelerations effective, by gradually accelerating the slow-up in two steps with a straight line and two, a smoother rising acceleration can be achieved. It is possible.

Of course, the example of FIG. 4 is an example of a speed pattern based on a total of eight straight lines. However, by increasing the number of divisions of this speed pattern, smoother acceleration can be performed at a portion required for the system. Needless to say.

The examples shown in FIGS. 3 and 4 are examples in which the number of divisions of the speed pattern is fixed. FIG. 6 shows an example of a speed command method in the case where the number of divisions is not fixed and can be varied. Will be explained.

In FIG. 6, first, "00"; acceleration, "01"; high speed constant speed, "10" by the first 2 bits;
Deceleration, "11"; divided into four types so as to indicate a constant low speed. Then, for each type, the acceleration α
Set u. That is, when the acceleration is “00”, the acceleration is α1 to
αm, constant speed RH, deceleration “1” at high speed constant speed “01”
0 ”, acceleration (deceleration) α1 to αn, low speed constant speed“ 1 ”
At 1 ", a constant speed RL is set.

As a result, among the acceleration "00", the high speed constant speed "01", the deceleration "10", and the low speed constant speed "11",
An arbitrary number of arbitrary accelerations or constant speeds are selected to switch the hardware operation unit. The switching timing from a certain acceleration to another acceleration, for example, the switching timing from α1 to α2, can be easily made generally by managing the number of output pulses.

As another method for making the number of divisions of the speed pattern variable, the upper two bits in the example shown in FIG. 6 are omitted, and the number of divisions of acceleration and deceleration is instructed in advance. Alternatively, a method of omitting the upper two bits by sequentially selecting the deceleration from the top in FIG.

Next, an example will be described in which a change in acceleration at a connecting portion between straight lines constituting a speed pattern is suppressed. FIG. 7 is an enlarged view of a portion A shown in FIG.
Focusing on the pulse signal outputs (e) to (e), the calculation is performed based on the initial speed, and the time when the inclination (acceleration) changes from the linear acceleration (α1) to the linear acceleration (α2) is (c). According to the usual calculation and the idea of switching the acceleration, the time point (c) is located at the intersection of the straight lines.

However, in this case, the speed change at the time (c) becomes abrupt, and vibration and other problems occur. Therefore, as shown in FIG. 8, the acceleration calculation at the time (c) is considered as an extension of the straight line, not as the start point of the straight line, and the switching is started with the inclination as the linear acceleration (α2), and the calculation is performed.

That is, when the speed at the time point (b) is Rb and the speed at the time point (c) is Rc, the following expression (3) is obtained. Rc = Rb + α2 / Rb (3) By calculating as in the above equation (3), as shown in FIG.
Compared to the case where the acceleration is calculated as α1, a change in the speed between the straight line and the connecting portion with the straight line is suppressed, and the occurrence of vibration and the like is suppressed.

As another example of a method for further suppressing the change between two straight lines, a straight line and a straight line, the acceleration is not switched from time (c) to time (α 2),
Alternatively, by replacing the acceleration with (α2) from the time (a), it is possible to ensure the smoothness of the connecting portion between the straight lines.

As a reverse method, as shown in FIG.
It is also possible to suppress the change in acceleration by calculating the time (d) at the acceleration (α1) and switching from the time (e) to the acceleration (α2) (the solid line in FIG. 9 indicates the time (d1)). ) Is calculated using acceleration (α2)). The above-described method of suppressing a change in acceleration is similarly applicable to deceleration pattern calculation.

FIG. 1B is a graph showing the acceleration change in FIG. 1A. As shown in FIG. 1B, the acceleration change is large in a portion where the acceleration changes from a straight line to a straight line. However, it is possible to suppress the rapid acceleration change by the above-described method.

Next, a description will be given of a method of correcting an error of the recurrence formula by the linear method. The recurrence equation shown in the above equation (1) is simple in terms of hardware operation, the operation time is short, and C
There is an advantage that the load on the PU can be extremely reduced. However, due to the recurrence formula, errors may occur due to an increase in speed and acceleration.

Therefore, as a method of suppressing the above error,
The following (1), (2), and (3) can be considered. (1) A pre-operation is performed in advance using a command value,
A method that estimates the error and changes the timing of correction of αu value or calculation switching. (2) Without performing a pre-calculation, an error direction / amount of a recurrence formula is calculated from a certain acceleration (inclination) and a speed range, and a correction value is previously learned from the calculated error, and the learned correction value is used. A method for performing the same correction as in (1). (3) When the calculation result is higher than the high-speed constant speed command value or lower than the low-speed constant speed command value, a correction system is provided with these comparison circuits to prevent the calculation value from exceeding the command value due to accumulation of calculation errors.

In the above methods (1) and (2), FIG.
In the example shown in (a), when the calculation result (α′u) has an error as indicated by the dotted line with respect to the ideal curve (αu), the value of the magnitude relation of (α′u)> (αu) , It is possible to approximate an ideal curve (solid line (αu)). Also, as the method of the above (3),
As shown in FIG. 10B, a limiter can be provided as the upper limit of the speed. Accurate speed control is possible with these error correction methods.

FIG. 11 shows an example of the configuration of the control section of the motor speed control device described above. The control unit in the example of FIG. 11 includes a control CPU 1 for starting a motor, a calculation unit 2 for performing an initial calculation and a correction calculation, and a multi-line approximate pulse calculation unit 3
(Control operation unit) and a motor phase output operation unit 4.

FIG. 12 shows an example of the configuration of the pulse calculator 3. This pulse calculation unit 3 can be implemented as an LSI,
Acceleration / deceleration calculation unit 31 for calculating equation (1), inclination switching unit 32 for switching and supplying inclination αu required for calculation to acceleration / deceleration calculation unit 31, constant speed calculation unit 34, acceleration / deceleration calculation unit 31 A switching circuit 35 for switching between the speed calculated by the above and a constant speed by the constant speed calculating unit 34, a switching timing instructing unit 33 for instructing the switching timing of the inclination switching unit 32 and the switching timing of the switching circuit 35, A period calculating unit 36 for calculating a period based on (2).

The acceleration / deceleration calculation section 31 has a mechanism for calculating the speed (Ri-1) one pulse before the speed Ri as an input for the calculation. That is, once activation is started, the processing can be shifted to another processing until an end report is received (interrupt or the like), and the CPU load is reduced.

According to the motor control apparatus according to the above-described embodiment of the present invention, the speed pattern composed of a plurality of straight lines is calculated using the simple recurrence formula (1), and the speed change point at the acceleration change point is calculated. Since the acceleration substituted into the recurrence formula (1) is the acceleration of the next straight line or the previous straight line, the change in the acceleration is suppressed, and the calculation error is also corrected.
It is possible to realize a motor control device that has a small calculation error and can sufficiently suppress a change in acceleration while using a simple calculation expression.

According to the motor control device of the present invention,
Since a simple arithmetic expression can be used, the load on the CPU can be significantly reduced. As a result, when controlling a plurality of motors, the communication function can be provided in the CPU as much as the load on the CPU is reduced, and the motors can be distributed and controlled by the plurality of CPUs with the communication function. Can be.

In this case, one CP having no communication function
The distance between the CPU and each motor can be reduced as compared with the case where all motors are controlled by U. Usually CPU
Since the control signal line between the motor and the motor is more complicated than the communication signal line between the CPUs, wiring of the signal line can be reduced. Further, the flexibility in constructing a hardware and software system by modularizing the motor can be increased.

That is, in the conventional case, (a) of FIG.
As shown in FIG. 1, a CPU 1 having a high function and a high processing capability
0 must be selected, and one CPU 10 needs to centrally control the plurality of motors 11-1, 11-1... 11-8. In this case, the load on the CPU 10 is not only increased due to the overlap, but also complicates the control method.
In terms of system construction, the larger and larger the system, the more complicated and difficult to change.

On the other hand, according to the motor control device of the present invention, since the load on the CPU is reduced, the motor control device has a communication function as shown in FIG. ... 1-n are respectively connected to a plurality of motors (11-1, 11-2), (11-3, 11-4),
(11-5, 11-6) can be controlled in a distributed manner.

As a result, the flexibility of system construction of hardware and software by reducing the number of control signal lines and modularizing the motor is increased, and the merit of so-called decentralization can be applied to the field of motor control.

[0054]

According to the motor control device of the present invention, while using a simple operation expression, the operation error is small, and
A motor control device capable of sufficiently suppressing a change in acceleration can be realized.

According to the motor control device of the present invention,
Since a simple arithmetic expression can be used, the load on the CPU can be significantly reduced. As a result, when controlling a plurality of motors, a communication function can be provided in the CPU as much as the load on the CPU is reduced, and each motor can be distributed and controlled by a plurality of CPUs with a communication function. In addition, it is possible to increase the flexibility of hardware and software system construction by reducing the number of control signal lines and modularizing the motor.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of an acceleration pattern based on a straight line.

FIG. 2 is a diagram illustrating an example of an output waveform of a pulse signal for controlling the speed of a motor.

FIG. 3 is a diagram showing an example of an acceleration / deceleration pattern composed of seven straight lines.

FIG. 4 is a diagram showing an example of an acceleration / deceleration pattern composed of eight straight lines.

FIG. 5 is a diagram showing another example of an acceleration / deceleration pattern composed of seven straight lines.

FIG. 6 is an explanatory diagram of a speed command method when the number of divisions of the speed pattern is variable.

FIG. 7 is an explanatory diagram of an example of suppressing a change in acceleration of a speed pattern.

FIG. 8 is an explanatory diagram of an example of a speed pattern in which a change in acceleration is suppressed.

FIG. 9 is an explanatory diagram of another example of a speed pattern in which a change in acceleration is suppressed.

FIG. 10 is a diagram showing an example of correction for a calculation error of a straight line.

FIG. 11 is a configuration diagram of a control unit of the motor speed control device.

FIG. 12 is an internal configuration diagram of a pulse calculation unit shown in FIG.

FIG. 13 is an explanatory diagram of an example in the case of controlling a plurality of motors.

FIG. 14 is an explanatory diagram of an example in which trapezoidal control is performed for motor speed control.

FIG. 15 is an explanatory diagram of an example in which motor speed control is controlled by an S-shaped curve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control CPU 2 Initial calculation and correction calculation part 3 Polylinear approximation pulse calculation part 4 Phase output calculation part 11-1 to 11-n Motor 31 Addition / subtraction calculation part 32 Inclination switching part 33 Switching timing part 34 Constant speed calculation part 35 Switching Circuit 36 Period calculation unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junichi Numata 882 Ma, Hitachinaka-shi, Ibaraki Pref.Measurement Division, Hitachi, Ltd. (72) Inventor Akira Inagaki 882 Ma, Hitachinaka City, Ibaraki Prefecture Incorporated Hitachi Machinery Division (72) Inventor Hiroshi Kikuchi 832 Nagakubo Horiguchi, Hitachinaka City, Ibaraki 2 Hitachi Measurement Engineering Stock In-house F-term (reference) 5H572 DD08 JJ03 5H580 FA14 FA29 FB05 FC09 FD09

Claims (6)

[Claims] A control pulse calculator for calculating a control pulse signal to be output to the motor; a phase output calculator for calculating a phase output of a control pulse output to the motor; and a control pulse calculator and a phase output calculator. A motor control device having a control unit for controlling an operation, wherein a speed straight line composed of a period and an acceleration is calculated by a predetermined simple calculation, and the calculated speed straight line is combined to calculate a motor speed pattern. A motor control device, comprising: a control operation unit that suppresses a change in acceleration at a connection portion between speed lines adjacent to each other. 2. The motor control device according to claim 1, wherein
The control calculation unit sets Ri as the speed of the i-th speed straight line,
If αu is the acceleration of the i-th speed line and Ri-1 is the slope of the i-1th speed line, Ri = Ri-1 + αu / Ri
According to the recurrence formula, the speed Ri of the i-th speed straight line is
And if the period of the i-th speed straight line is ti,
A motor control device, wherein a period ti of the i-th speed straight line is calculated by the following equation: ti = 1 / Ri. 3. The motor control device according to claim 2, wherein
The control calculation unit calculates Ri = Ri-1 + αu + 1 / Ri-1, where αi + 1 is the acceleration of the (i + 1) th speed line at the connection part between the adjacent speed lines, and A motor control device that suppresses a change in acceleration at a connection portion between speed lines adjacent to each other by performing calculation using the following expression. 4. The motor control device according to claim 1, wherein
A motor control device further comprising a communication function of communicating control information to another motor control device. 5. The motor control device according to claim 1, wherein the control operation unit includes an LS control unit.
I. A motor control device, wherein 6. The motor control device according to claim 1, wherein an error in the acceleration of the speed line calculated by the control calculation unit is calculated, and a correction value is calculated based on the calculated error. A motor control device comprising a learning function for calculating.