JP2000083392A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain smooth speed command, current and torque with respect to the change in speed command input by converting speed command input to the speed command of trapezoid +S shape by adding restrictions with a trapezoidal accelerator command and controlling the current applied to a motor in response to the deviation from actual speed. SOLUTION: An interval of acceleration, where an acceleration command of an unit step is added for each sampling cycle becomes an S-shaped speed command, and an interval restricted by the maximum acceleration command becomes a trapezoidal leg portion speed command. Then the speed command pattern is output from a converter 5 as a speed command 1, a current applied to the motor is controlled, in response to the deviation from the true speed signal from a speed command signal 1 and speed measuring means 8 by motor control means 7 so as to obtain a speed pattern almost equal to that of the speed command 1. Also similarly, deceleration pattern is also abstained. In this way, smooth speed command, current and torque can be obtained with respect to changes in speed command input with simple configuration and calculations.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling the speed of a motor.

[0002]

2. Description of the Related Art In a conventional control device for controlling the speed of a motor, for example, when a start command is turned on / off and the speed command changes rapidly during acceleration or deceleration, the speed command is given without conversion. Alternatively, the acceleration current is limited by a constant acceleration command, converted into a so-called trapezoidal speed command and given, and the current supplied to the motor is controlled in accordance with a deviation from the actual speed of the motor.

[0003]

In the above-described conventional control device for controlling the speed of a motor, for example, when a speed command changes, a motor current corresponding to the change flows. In the case of a change, a maximum acceleration current or a deceleration current flows, and there is a problem that an excessive change in torque is caused to the load.

[0004]

SUMMARY OF THE INVENTION In order to solve this problem, a motor control device according to the present invention is a digital motor control system which performs processing at a constant sampling period, and is limited by a trapezoidal acceleration command. The present invention includes a conversion means for converting a speed command input into a trapezoidal + S-shaped speed command, and a motor control means for controlling a current supplied to the motor in accordance with a deviation from the actual speed. A smooth speed command, current, and torque can be obtained with respect to the change.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention provides an oscillator for outputting a sampling signal having a fixed period, and an A / D converter for converting an analog signal into a digital signal and outputting a speed command. Converter, a conversion means for converting a speed command to output a speed command 1, a rotation position detector for detecting a rotation position of a motor, and an actual speed measurement means for counting a rotation position detection signal and outputting an actual speed signal And the speed command 1
And a motor control means for controlling the current supplied to the motor by comparing the actual speed signal with the actual speed signal, wherein the converting means sets a change value of the acceleration command allowed per sampling cycle as a jerk of a unit step and sets the maximum acceleration command to The arrival speed command at the time when the acceleration command becomes 0 is calculated by defining the number of steps as a multiple of the jerk command, and the command acceleration during the next sampling cycle is determined by comparing the calculation result with the speed command. Since the speed command is converted into a trapezoidal + S-shaped waveform, the current change becomes smooth, so that the motor control with a smooth torque change becomes possible.

According to a second aspect of the present invention, the conversion means comprises an acceleration setting means and a speed command conversion means, and the acceleration setting means converts a change value of the acceleration command allowed per sampling period into a unit step. Jerk command ΔA
And outputs the maximum acceleration command during acceleration and the minimum acceleration command (negative) during deceleration as Qa and Qd.
The speed command converting means adds 0, +1 and -1 to the current acceleration step number Q0 under the limitation of the Qa and Qd for each sampling cycle to obtain a new acceleration step number Qk, and three types of Qk , The arrival speed command at the time when the acceleration command becomes 0 is calculated, a new acceleration step number Qk is determined by comparing each arrival speed command with the speed command 1 input, and the new speed command Vk is changed to the current speed command V0. It is configured to calculate and output the equation Vk = V0 + ΔA × Qk as a reference, so that a trapezoidal + S-shaped speed command waveform can be obtained based on a simple digital control algorithm.

According to a third aspect of the present invention, the acceleration setting means includes an S-shaped speed command time T1 and a sampling period T
For the s input, the maximum number of steps Qa during acceleration is given by Qa = T1 /
Ts, the jerk command ΔA is obtained by ΔA = Sm / (Ta × Qa) with respect to the speed difference Sm and the acceleration time Ta input, and further, the deceleration minimum step number Qd is obtained by the deceleration time Td input.
Is obtained by Qd = −Sm / (Td × ΔA), and ΔA, Qa,
This is a system in which Qd is output, and the system gives a trapezoidal + S-shaped speed command by instructing a time and a speed at which the operator is relatively easy to operate.

According to a fourth aspect of the present invention, the acceleration setting means includes a nonvolatile memory, and stores the jerk ΔA, the maximum step number Qa during acceleration, and the minimum step number Qd during deceleration. By setting three control parameters in a non-volatile memory, a predetermined trapezoid +
The system obtains an S-shaped speed command.

According to a fifth aspect of the present invention, the speed command converting means converts the arrival speed command Vd to Vd = (V0 + ΔA ×
Qk × (Qk + 1)) / 2, and it is possible to calculate the arrival speed command at the time when the acceleration becomes 0 in the shortest time by a simple calculation.

[0010]

Embodiments of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram showing an embodiment of the present invention. Reference numeral 1 denotes a volume for setting a speed command, and an A / D converter 2 controls a speed command voltage of 0 V to Vc.
To enter. Reference numeral 3 denotes a switch for instructing driving and stopping of the motor 4. When the switch 3 is turned on, the speed command voltage is fixed at 0 V and the stop is commanded. 5 is A
Upon receiving the digitally converted speed command from the / D converter, the speed command is converted into a speed command during the sampling period Ts in synchronization with a pulse-like sampling signal having a constant period Ts from the oscillator 6 and the speed command 1 7 is a motor control means for controlling a current supplied to the motor 4, and 8 is a pulse-shaped rotation position signal from a rotation position detector 9 for detecting the rotation position of the motor shaft. The figure shows a speed measuring means for counting the sampling period and outputting an actual speed signal of the motor. The converting means 5, the control unit of the motor control means 7 and the speed measuring means 8 are usually controlled by a microcomputer.

The operation of the present invention configured as described above will be described below with reference to the time chart of FIG.

First, when the switch 3 is turned off by the operator, the motor 4 operates at the speed Sm set by the potentiometer 1.
It is started toward. The converting means 5 compares the speed command input with the speed command input based on the acceleration command approximated by the trapezoidal acceleration command, converts the speed command into a speed command 1 for each sampling cycle, and outputs the speed command.
That is, the change value of the acceleration command allowed in each sampling cycle is defined as the jerk of the unit step, and the maximum acceleration command is defined as a step number that is a multiple of the jerk command, and the arrival speed command at the time when the acceleration command becomes 0 is defined. The acceleration command for the next sampling period is determined by comparing the calculation result with the speed command, and the speed command 1 is processed so as to be output. The jerk command in the unit step is added for each sampling period. The section of the applied acceleration is the S-shaped speed command, and the section limited by the maximum acceleration command is the trapezoidal leg speed command. In this way, S-shaped →
A speed command pattern in trapezoidal (leg) → S-shaped → trapezoidal (Sm) acceleration is output from the converter 5 as a speed command 1, and the motor control means 7 outputs the speed command signal 1 and an actual speed signal from the speed measuring means 8. The operation is performed so as to obtain a speed pattern substantially equal to the speed command 1 by controlling the current supplied to the motor in accordance with the deviation from. On the other hand, when the switch 1 is turned on, the speed command becomes 0, so that the acceleration becomes negative. In the same manner as described above, the S-shaped → trapezoidal (leg) → S-shaped →
A trapezoidal (speed 0) deceleration pattern is obtained.

Here, the converting means 5 comprises an acceleration setting means 10 and a speed command converting means 11 as shown in FIG. 3. First, the operation of the acceleration setting means 10 will be described with reference to the block diagram of FIG. I will describe.

If the smoothness is set as the speed command time T1 of the S-shaped section in accordance with the acceleration / deceleration characteristics of the load, the maximum number of steps Qa during acceleration in process 12 is given by Qa = T1 / It is calculated by Ts and output. Here, the maximum number of steps during acceleration Qa is rounded to an integer value as the number of steps of quantized jerk ΔA described later. On the other hand, if the acceleration time Ta of the speed difference Sm is set, the maximum acceleration during acceleration Aa is set to Aa = S
m / Ta, and the jerk ΔA is calculated and output by processing 14 as ΔA = Aa / Qa. When the deceleration time Td of the speed difference Sm is set, the processing 1
5, the minimum acceleration during deceleration Ad is calculated by Ad = −Sm / Td, and the minimum number of steps Qd during deceleration is calculated and output by processing 16 as Qd = Ad / ΔA. As described above, the minimum step number Qd during deceleration is rounded to an integer value.

As described above, the acceleration setting means 10 outputs the jerk ΔA, the maximum number of steps during acceleration Qa, and the minimum number of steps during deceleration Qd (negative). Although the above description has been given of the processing in the case where the S-shaped speed command time T1 during acceleration is set, the same processing can be performed in the case where the S-shaped speed command time during deceleration is set. However, it is effective as another embodiment of the present invention.

In the above, one embodiment of the acceleration setting means 10 has been described. However, as another embodiment, the acceleration setting means 10 is a non-volatile memory, and the maximum number of steps during acceleration Q
The present invention is effective (not shown) even if a, the jerk ΔA, and the minimum number of steps Qd during deceleration are stored in the memory.

Next, the detailed operation of the speed command converter 11 will be described with reference to FIGS. 5 (a), 5 (b) and 6.

FIGS. 5A and 5B are time charts showing a speed conversion process of the speed command conversion means 11, wherein FIG.
Indicates a time of deceleration, and FIG. 6 similarly shows a flowchart.

In FIG. 5, the acceleration command is represented by a quantized jerk command ΔA as a unit step.
It is updated every sampling period and its change is limited by a unit step, ie, jerk ΔA, and the current number of acceleration steps is Q0. On the other hand, the speed command is obtained by adding the acceleration command to the current speed command V0 every sampling period Ts. Here, the change in acceleration for each sampling cycle Ts is limited as the jerk ΔA of the unit step, so that the new acceleration step number Qk is calculated based on the current acceleration step number Q0.
Is any one of Q0 + 1, Q0, and Q0-1, and the new speed command Vk is as follows: Vk = V0 + ΔA × Qk (1). The command pattern is shown in FIG. Here, the reaching speed command Vd at the time when the acceleration command becomes 0 is obtained by adding the changing speed command Vc expressed as an integral value of the acceleration command to the current speed command V0, that is, the new acceleration step number is represented by Qk. Then, Vd = V0 + ΔA × Qk × (Qk + 1) / 2 (2)

Regarding the above three new accelerations (2)
Substituting into the equation, calculating the arrival speed command Vd and comparing it with the speed command input Vt, one new acceleration satisfying the condition of Vt ≧ Vd with the maximum acceleration command pattern during acceleration and the minimum acceleration command pattern during deceleration. To determine. The number of new acceleration command steps Qk determined in the embodiment of FIG. 5 is Qk = Q0 both during acceleration and deceleration.

The number of new acceleration steps Qk determined above
Into the equation (1) to calculate a new speed command Vk and output it as the speed command 1.

The above-described operation is described in the flowchart of FIG. 6 separately for acceleration and deceleration. As shown in the figure, an S-shaped + trapezoidal speed command pattern can be obtained by a simple calculation formula.

[0024]

As described above, according to the motor control device of the present invention, in a digital motor control system which performs processing at a fixed sampling period, a speed command input is restricted by a trapezoidal acceleration command so that a speed command input is trapezoidal + S-shaped. And a motor control means for controlling a current supplied to the motor in accordance with a deviation from the actual speed. According to the present invention, a change in the speed command input is obtained by a simple configuration and calculation. , A smooth speed command, current and torque can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a time chart showing the operation of the present invention.

FIG. 3 is a block diagram of a conversion unit 4;

FIG. 4 is a block diagram showing processing of an acceleration setting means 10;

5A is a time chart showing the operation of the speed command converter 11 during acceleration, and FIG. 5B is a time chart showing the operation of the speed command converter 11 during deceleration.

FIG. 6 is a flowchart showing the operation of the speed command converter 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Volume 2 A / D converter 3 Switch 4 Motor 5 Conversion means 6 Oscillator 7 Motor control means 8 Speed measurement means 9 Rotational position detector 10 Acceleration setting means 11 Speed command conversion means

Claims (5)

[Claims] An oscillator that outputs a sampling signal having a fixed period, an A / D converter that converts an analog signal into a digital signal and outputs a speed command, and converts a speed command and outputs a speed command 1 Converting means, a rotational position detector for detecting the rotational position of the motor, an actual speed measuring means for counting the rotational position detection signal and outputting an actual speed signal, and comparing the speed command 1 with the actual speed signal. A motor control means for controlling a current supplied to the motor, wherein the conversion means sets a change value of the acceleration command allowed per sampling cycle as a jerk of a unit step, and sets the maximum acceleration command to a step number which is a multiple of the jerk command. The arrival speed command at the time when the acceleration command becomes 0 is calculated, and the command acceleration during the next sampling cycle is determined by comparing the calculation result with the speed command. A motor control device that outputs a degree command 1. 2. The conversion means comprises acceleration setting means and speed command conversion means. The acceleration setting means quantizes and outputs a change value of the acceleration command allowed per sampling period as a jerk command ΔA in unit steps. The maximum acceleration command during acceleration and the minimum acceleration command (negative) during deceleration are output as Qa and Qd, and the speed command conversion means converts the current acceleration step number Q0 to Qa for each sampling cycle.
Under the restrictions of Qd and Qd, 0, +1 and -1 are added to obtain a new acceleration step number Qk, and the arrival speed commands at the time when the acceleration command becomes 0 for three types of Qk are calculated. 2. The new acceleration step number Qk is determined by comparing the command and the speed command 1 input, and the new speed command Vk is calculated and output based on a formula of Vk = V0 + ΔA × Qk based on the current speed command V0. Motor control device. 3. The acceleration setting means includes an S-shaped speed command time T1.
The maximum step number during acceleration Qa is obtained by Qa = T1 / Ts with respect to the input of the sampling period Ts and the input of the jerk command ΔA is given by ΔA = Sm / (T
a × Qa), and the minimum number of steps Qd during deceleration is given by Qd = −Sm / (Td × ΔA) in response to deceleration time Td input.
3. The motor control device according to claim 2, wherein ΔA, Qa, and Qd are output. 4. The motor control device according to claim 2, wherein the acceleration setting means includes a non-volatile memory, and stores the jerk ΔA, the maximum number of steps during acceleration Qa, and the minimum number of steps during deceleration Qd. 5. The motor control device according to claim 2, wherein the speed command converting means obtains the reached speed command Vd by Vd = (V0 + ΔA × Qk × (Qk + 1)) / 2.