JPH06189598A - Drive controller for stepping motor - Google Patents

Abstract

(57) [Abstract] [Purpose] In a stepping motor drive controller that divides the basic step angle of a stepping motor into n steps and drives in a microstep, there is a difference between the excitation position and the rotor position due to loss such as rotor friction. (EN) Provided is a drive control device for a stepping motor, which alleviates a hysteresis phenomenon that a phase difference occurs at a position and the stop position is slightly displaced. [Arrangement] An up / down counter 1 for counting clock pulses, and a selector 6 for switching correction data by a counting direction signal (UP / DOWN) of the up / down counter.
An adder 5 for performing an addition operation on the count output of the up / down counter and the output data of the selector; and data read out using the output data from the adder as address data to obtain amplitude data of sine wave and cosine wave. It is provided with ROMs 2a and 2b stored in memory addresses, and exciting current control units 3a and 3b for converting amplitude data of sine wave and cosine wave read from the ROM into exciting currents of the motor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a stepping motor in which the basic step angle of the stepping motor is divided into n steps for microstep driving. And a rotor position, a phase difference is generated, and the hysteresis phenomenon that the stop position is slightly displaced is characterized.

[0002]

2. Description of the Related Art In recent years, micro-step drive of a stepping motor has been frequently used as a magnetic head drive source for a magnetic disk drive.

A conventional drive control device for a stepping motor will be described below. FIG. 7 shows the configuration of a conventional drive control device for a stepping motor. In FIG. 7, 1 is an up / down counter that counts up or down the clock pulse CP by the rotation direction signal UP / DOWN, 2a and 2b are ROMs storing amplitude data of sine wave and cosine wave, and 31a and 31b are up and down. The output of the counter 1 is used as address data for each ROM 2
D / A converters that convert the amplitude data read from a and 2b into analog signals, and 32a and 32b are the D / A converters.
A drive circuit for driving a stepping motor in accordance with an analog signal output from the A converter, 3a and 3b are excitation current control units including the D / A converters 31a and 31b and drive circuits 32a and 32b, 4 is a stepping motor, 4a,
4b is a stator coil of the stepping motor 4.

The operation of the drive control device for the stepping motor configured as described above will be described with reference to FIG. FIG. 8 shows the rotation direction signal UP / DOW from the state in which the initial state of the stepping motor is stationary in the reverse direction.
The state of each part when N is turned up (H) and the rotation direction signal UP / DOWN is turned down (L) after rotating by four basic steps in the forward rotation direction to switch the rotation in the reverse rotation direction is shown. First, when the counting direction of the up / down counter 1 is set by the rotation direction signal UP / DOWN and the clock pulse CP is input, the up / down counter 1 starts counting operation. Using the count value of the up / down counter 1 as address data, the amplitude data of the sine wave and the cosine wave are sequentially read from the ROMs 2a and 2b, and the D / A converters 31a and 31b of the exciting current control units 3a and 3b are read.
Is converted into an analog signal and input to the drive circuits 32a and 32b as an excitation signal. The drive circuit drives the stator coils 4a and 4b of the stepping motor 4 by constant current drive, for example. When the clock pulse CP is input and the up-down counter 1 starts the counting-up operation, the rotation angle of the excitation position moves in the positive direction, a phase difference occurs between the rotation position and the rotor position, and torque is generated. When the torque generated by the motor becomes large enough to reach the equilibrium state with the maximum positive friction torque, the rotor of the motor starts moving and follows the excitation position. Rotation direction signal UP / DO
When WN is reversed and the up / down counter 1 counts down, the rotation angle of the excitation position moves in the opposite direction, the phase difference between the excitation position and the rotor position becomes opposite, and the maximum friction torque in the opposite direction increases. When the torque generated in the opposite direction increases until the equilibrium state is reached, the rotor follows the excitation position.

[0005]

However, in the above-mentioned conventional structure, a phase difference occurs between the excitation position and the rotor position due to a loss such as friction of the stepping motor, and the stop position is slightly displaced. That is, there is a problem that accurate positioning cannot be performed because of the hysteresis phenomenon.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a drive control device for a stepping motor capable of reducing the hysteresis phenomenon.

[0007]

In order to achieve this object, the apparatus of the present invention selects two kinds of correction data according to the rotation direction of the excitation position designation data of the stator coil, and selects the correction data as the excitation position designation data. The configuration is such that correction data is added.

[0008]

With this configuration, when the rotation direction of the excitation position designation data is switched so as to reverse the rotation direction of the stepping motor, the correction data added to the excitation position designation data is also switched. By setting this correction data to the phase difference of the excitation position corresponding to the loss such as friction, when the rotation direction of the stepping motor is reversed, the torque for the loss caused by friction can be immediately generated, and the stepping The hysteresis phenomenon of the motor can be reduced.

[0009]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a rotation direction signal UP / D.
An up / down counter for counting up or down the clock pulse CP by OWN, 6 is a forward rotation direction correction data (DATA) by the rotation direction signal UP / DOWN.
The selector 5 for selecting either 1) or the reverse rotation direction correction data (DATA2) adds the correction data output from the selector 6 to the excitation position designation data output from the up / down counter 1 Adders 2a and 2b are ROMs storing amplitude data of sine wave and cosine wave, 31
a and 31b are D / A converters for converting the amplitude data read from the ROMs 2a and 2b into analog signals by using the output of the adder 5 as address data, and 32a and 32b are according to the output signals of the D / A converters. Driving circuits for driving the stepping motors, 3a and 3b are excitation current control units composed of the D / A converters 31a and 31b and driving circuits 32a and 32b, 4 is a stepping motor, 4a,
4b is a stator coil of the stepping motor 4. An up / down counter of 1 and R of 2a and 2b
The OM, 3a, 3b excitation current control units, 31a, 31b D / A converters, 32a, 32b drive circuits, 4 stepping motors, 4a, 4b stator coils have the same configurations as in the conventional example.

The operation of the drive control device for the stepping motor configured as described above will be described with reference to FIG. FIG. 2 shows the rotation direction signal UP / DOW from the state in which the initial state of the stepping motor is stationary in the reverse direction.
The state of each part when N is turned up (H) and the rotation direction signal UP / DOWN is turned down (L) after rotating by four basic steps in the forward rotation direction to switch the rotation in the reverse rotation direction is shown. The ROMs 2a, 2b, 3a, 3
The exciting current controller b, the D / A converters 31a and 31b, the drive circuits 32a and 32b, the stepping motors 4 and the stator coils 4a and 4b operate in the same manner as in the conventional example, and the ROMs 2a and 2b adders. The output data of 5 is input as address data, the amplitude data of the sine wave and the cosine wave corresponding to the address data is read, and converted into analog signals by the D / A converters 31a and 31b of the excitation current control units 3a and 3b. Drive circuit 32 as an excitation signal
a, 32b. The drive circuit uses, for example, a constant current drive to drive the stator coil 4 of the stepping motor 4.
Drive a and 4b.

First, the rotation direction signal UP / DOW
Since N is in the down (L) state, the selector 6 outputs the reverse rotation direction correction data (DATA2). Here, the reverse rotation direction correction data is a negative value, which is slightly smaller than the value of the phase difference corresponding to the maximum friction torque in the reverse rotation direction. At this time, the torque generated by the stepping motor is in equilibrium with the maximum friction torque in the reverse rotation direction, and the excitation position of the stator coil with respect to the rotor position of the stepping motor is
The phase is advanced in the negative direction, which is the reverse direction.

When the rotation direction signal UP / DOWN is turned up (H), the output of the selector 6 is switched to the normal rotation direction correction data (DATA1), and the output data of the adder 5 is also switched. Here, the normal direction correction data is a positive value,
The value is slightly smaller than the value of the phase difference corresponding to the maximum friction torque in the forward direction. As a result, the excitation position of the stator coil advances in phase in the positive direction, which is the forward rotation direction, with respect to the rotor position, and the torque generated by the stepping motor is also generated in the forward rotation direction. However, since this generated torque is smaller than the maximum friction torque in the normal rotation direction, the rotor remains stationary. In this state, when the clock pulse CP is input and the up / down counter 1 counts up, the excitation position advances in the positive direction, and the torque generated by the stepping motor increases in the forward direction. When the generated torque reaches the maximum friction torque in the forward rotation direction, the rotor of the stepping motor rotates in the forward rotation direction so as to follow the excitation position so that the generated torque and the maximum friction torque are in equilibrium.

Next, when the rotation direction signal UP / DOWN is turned down (L), the output of the selector 6 is switched to the reverse rotation direction correction data (DATA2), and the output data of the adder 5 is also switched. As a result, the excitation position of the stator coil advances in phase in the negative direction, which is the reverse direction with respect to the rotor position, and the torque generated by the stepping motor is also generated in the reverse direction. However, since this generated torque is smaller than the maximum friction torque in the reverse rotation direction, the rotor remains stationary.
In this state, when the clock pulse CP is further input, the up / down counter 1 starts counting down, so that the excitation position advances in the negative direction and the torque generated by the stepping motor increases in the reverse direction. When the generated torque reaches the maximum friction torque in the reverse rotation direction, the rotor of the stepping motor follows the excitation position and rotates in the reverse rotation direction so that the generated torque and the maximum friction torque are in equilibrium.

The reason why the values of the correction data in the normal rotation direction and the reverse rotation direction in this embodiment are slightly smaller than the value of the phase difference corresponding to the maximum friction torque is that the maximum friction torque varies, and if the rotation This is because, if the torque generated by the stepping motor generated by the correction data when the direction is reversed becomes larger than the maximum friction torque, the rotor position will operate discontinuously.

As described above, according to this embodiment, when the rotation direction of the excitation position designation data is switched so as to reverse the rotation direction of the stepping motor, the correction data added to the excitation position designation data is also switched. By setting this correction data to a value that is slightly smaller than the phase difference of the excitation position corresponding to the loss such as friction, when the rotation direction of the stepping motor is reversed, most of the torque for the loss caused by friction is immediately generated. Therefore, the hysteresis phenomenon of the stepping motor can be reduced.

In this embodiment, the selector 6 selects the correction data (DATA1) in the forward rotation direction and the correction data (DATA2) in the reverse rotation direction.
However, if the absolute values of the correction data in the forward rotation direction and the correction data in the reverse rotation direction may be the same, the correction data to be input is set to one type and the rotation direction signal UP is used instead of the selector 6. A circuit for inverting the sign by / DOWN may be used. In this case, the input data can be reduced and the circuit configuration can be simplified. In addition, the configuration of the exciting current control units 3a and 3b may be replaced with the D / A converters 31a and 31b, and a PWM control circuit that modulates input data in a pulse width time may be used.

(Embodiment 2) A second embodiment of the present invention will be described below with reference to FIGS. The difference between the second embodiment and the first embodiment described above is that in the first embodiment, the correction data to be added to the adder 5 is preset and the selector is selected according to the rotation direction. However, in the present embodiment, the second clock pulse is counted by the second up-down counter 63 for a predetermined period according to the rotation direction at the start of driving, The count value is applied to the adder 5 as correction data.

FIG. 4 shows that the stepping motor of the second embodiment has an initial state in which it is stationary in the reverse rotation direction, and then the rotation direction signal UP / DOWN is turned up (H) to 4 steps at the basic step angle in the forward rotation direction. The state of each part when the rotation direction signal UP / DOWN is turned down (L) and the rotation in the reverse direction is switched after the angular rotation is shown.

First, the rotation direction signal UP / DOW
N is in the down (L) state. At this time, the torque generated by the stepping motor is in equilibrium with the maximum friction torque in the reverse rotation direction, and the excitation position of the stator coil has its phase advanced in the negative direction, which is the reverse rotation direction, with respect to the rotor position of the stepping motor. Is in a state.

When the rotation direction signal UP / DOWN is turned up (H), the monostable multivibrator 61 outputs the signal (H) for a preset time by the input of the rising edge. The monostable multivibrator 61
Is outputting the signal (H), the output of the and gate circuit passes the second clock pulse CLK, and the second up / down counter 63 performs the counting up operation. At this time, the frequency of the second clock pulse CLK is set higher than the frequency of the first clock pulse CP. By the count-up operation of the second up-down counter 63, the excitation position of the stator coil advances in phase in the positive direction, which is the forward direction with respect to the rotor position, and the torque generated by the stepping motor is also generated in the forward direction. Come to do.

While the generated torque is smaller than the maximum friction torque in the normal direction, the rotor remains stationary, but the second clock pulse CLK is the first clock pulse CP.
Since the frequency is higher, the stationary time is shorter. In this state, when the clock pulse CP is input and the up / down counter 1 counts up, the excitation position further advances in the positive direction, and the torque generated by the stepping motor increases in the forward direction. When the generated torque reaches the maximum friction torque in the forward rotation direction, the rotor of the stepping motor rotates in the forward rotation direction so as to follow the excitation position so that the generated torque and the maximum friction torque are in equilibrium.

Next, when the rotation direction signal UP / DOWN is turned down (L), the monostable multivibrator 61 outputs the signal (H) for a preset time by the input of the falling edge. The monostable multivibrator 6
While 1 is outputting the signal (H), the output of the and gate circuit passes the second clock pulse CLK, and the second up / down counter 63 performs the counting down operation. At this time, the frequency of the second clock pulse CLK is set higher than the frequency of the first clock pulse CP. By the counting down operation of the second up / down counter 63, the excitation position of the stator coil advances in phase in the negative direction which is the reverse direction with respect to the rotor position, and the torque generated by the stepping motor is also generated in the reverse direction. become.

While the generated torque is smaller than the maximum friction torque in the reverse rotation direction, the rotor remains stationary, but the second clock pulse CLK changes to the first clock pulse CP.
Since the frequency is higher, the stationary time is shorter. In this state, when the clock pulse CP is further input and the up / down counter 1 counts down, the excitation position further advances in the negative direction, and the torque generated by the stepping motor increases in the reverse direction. When the generated torque reaches the maximum friction torque in the reverse rotation direction, the rotor of the stepping motor follows the excitation position and rotates in the reverse rotation direction so that the generated torque and the maximum friction torque are in equilibrium.

As described above, according to this embodiment, the rotation direction signal UP is set so as to reverse the rotation direction of the stepping motor.
When the / DOWN is switched, the second up / down counter performs counting operation for a preset time, and when the rotation direction of the stepping motor is reversed, the loss torque caused by friction or the like can be corrected at high speed. The hysteresis phenomenon of the stepping motor can be reduced. Further, by setting the time at which the monostable multivibrator generates an output signal and the frequency of the second clock pulse CLK, it is possible to freely correspond to the torque corresponding to the loss caused by friction that changes variously depending on the load of the stepping motor. it can.

(Third Embodiment) A third embodiment of the present invention will be described below with reference to FIGS. The difference between the third embodiment and the second embodiment described above is that in the second embodiment, the second clock pulse is applied for a predetermined period according to the rotation direction at the start of driving. The count value is counted by the up / down counter 63 of No. 2, and the count value is applied to the adder 5 as the correction data. However, in the present embodiment, at the start of driving, only the predetermined period is determined depending on the rotation direction. The clock pulse applied to the up / down counter 1 of 1 is switched to the second clock pulse,
The count value of the first up / down counter 1 is corrected.

FIG. 6 shows that the stepping motor of the third embodiment has an initial state in which it is stationary in the reverse rotation direction, the rotation direction signal UP / DOWN is turned up (H), and the basic step angle is 4 steps in the forward rotation direction. The state of each part when the rotation direction signal UP / DOWN is turned down (L) and the rotation in the reverse direction is switched after the angular rotation is shown.

First, the rotation direction signal UP / DOW
N is in the down (L) state. At this time, the torque generated by the stepping motor is in equilibrium with the maximum friction torque in the reverse rotation direction, and the excitation position of the stator coil has its phase advanced in the negative direction, which is the reverse rotation direction, with respect to the rotor position of the stepping motor. Is in a state.

When the rotation direction signal UP / DOWN is turned up (H), the monostable multivibrator 61 outputs the signal (H) for a preset time by the input of the rising edge. The monostable multivibrator 61
While the signal is outputting the signal (H), the selector 64 selects and outputs the second clock pulse CLK having a high frequency.
Here, the second clock pulse CLK is always input. While the selector 64 is outputting the second clock pulse CLK, the up / down counter 1 performs a counting up operation at high speed. By the counting-up operation of the up / down counter 1, the excitation position of the stator coil advances in phase in the positive direction which is the forward rotation direction with respect to the rotor position,
The torque generated by the stepping motor is also generated in the forward rotation direction.

While the generated torque is smaller than the maximum friction torque in the forward direction, the rotor remains stationary, but the second clock pulse CLK has a high frequency, so the stationary state is for a short period of time. . In this state, when the output signal of the monostable multivibrator 61 returns to the initial state signal (L) and the first clock pulse CP is input, the selector 64 selects and outputs the first clock pulse CP. To do. When the up / down counter 1 counts up by the first clock pulse CP output from the selector 64, the excitation position further advances in the positive direction, and the torque generated by the stepping motor increases in the normal direction. When the generated torque reaches the maximum friction torque in the forward rotation direction, the rotor of the stepping motor rotates in the forward rotation direction so as to follow the excitation position so that the generated torque and the maximum friction torque are in equilibrium.

Next, when the rotation direction signal UP / DOWN is turned down (L), the monostable multivibrator 61 outputs the signal (H) for a preset time by the input of the falling edge. The monostable multivibrator 6
While 1 is outputting the signal (H), the selector 64 selects and outputs the second clock pulse CLK having a high frequency. While the selector 64 is outputting the second clock pulse CLK, the up / down counter 1 performs counting down operation at high speed. Due to the counting down operation of the up / down counter 1, the excitation position of the stator coil advances in phase in the negative direction, which is the reverse direction with respect to the rotor position, and the torque generated by the stepping motor is also generated in the reverse direction.

While the generated torque is smaller than the maximum friction torque in the reverse rotation direction, the rotor is in a stationary state, but the stationary state is a short period because the second clock pulse CLK has a high frequency. In this state, the output signal of the monostable multivibrator 61 returns to the initial state signal (L), and the selector 64 also outputs the first clock pulse C.
When P is selected and returned to the output state, the up / down counter 1 further counts down, the excitation position further advances in the negative direction, and the torque generated by the stepping motor increases in the reverse direction. When the generated torque reaches the maximum friction torque in the reverse rotation direction, the rotor of the stepping motor follows the excitation position and rotates in the reverse rotation direction so that the generated torque and the maximum friction torque are in equilibrium.

[0033]

As described above, according to the present invention, when the rotation direction of the excitation position designation data is switched so as to reverse the rotation direction of the stepping motor, the correction data added to the excitation position designation data is also switched, and the friction data causes friction. It is possible to realize an excellent drive control device for a stepping motor that can immediately generate a torque corresponding to the generated loss and reduce the hysteresis phenomenon of the stepping motor.

[Brief description of drawings]

FIG. 1 is a block diagram of a drive control device for a stepping motor according to a first embodiment of the present invention.

FIG. 2 is a time chart for explaining the operation of the drive control device for the stepping motor in the first embodiment.

FIG. 3 is a block diagram of a drive control device for a stepping motor according to a second embodiment of the present invention.

FIG. 4 is a time chart for explaining the operation of the drive control device for the stepping motor in the second embodiment.

FIG. 5 is a block diagram of a drive control device for a stepping motor according to a third embodiment of the present invention.

FIG. 6 is a time chart for explaining the operation of the drive control device for the stepping motor in the third embodiment.

FIG. 7 is a block diagram of a conventional drive control device for a stepping motor.

FIG. 8 is a time chart for explaining the operation of a conventional stepping motor drive control device.

[Explanation of symbols]

 1 Up-down counter 2a ROM 2b ROM 3a Excitation current control unit 3b Excitation current control unit 31a D / A converter 31b D / A converter 32a Drive circuit 32b Drive circuit 4 Stepping motor 4a Stator coil 4b Stator coil 5 Adder 6 Selector 61 Monostable multivibrator 62 and gate circuit 63 Up-down counter 64 Selector

Claims (3)

[Claims] 1. A current having an amplitude for exciting an exciting position according to a count value of a first up / down counter that counts up or counts down a first clock pulse according to a rotation direction is created, and the current is generated by a stator. In a drive control device for a stepping motor that applies a micro step by applying to a coil, one of two types of first correction data values is selected according to the rotation direction, and the selected correction data is the count value of the up / down counter. And a current having an amplitude for exciting an exciting position according to the added value is created. 2. A current having an amplitude for exciting an exciting position corresponding to a count value of a first up / down counter that counts up or counts down a first clock pulse according to a rotation direction is created, and the current is generated by a stator. In a drive control device of a stepping motor that applies a micro step by applying to a coil, a second up / down counter counts up or counts down a second clock pulse according to a rotation direction for a predetermined period at the start of driving. A stepping motor drive control device, wherein the count value is added to the count value of the first up / down counter, and a current having an amplitude for exciting an exciting position according to the added value is created. 3. A current having an amplitude for exciting an exciting position according to a count value of a first up / down counter that counts up or counts down a first clock pulse according to a rotation direction is created, and the current is generated by a stator. In a drive control device for a stepping motor which applies a micro step to a coil and drives the coil, the first step is performed for a predetermined period at the start of driving.
Second clock pulse whose repetition period is smaller than that of the first clock pulse is counted up or down according to the rotation direction, and then the first clock pulse is continuously counted, and the excitation position corresponding to the counted value is excited. A drive control device for a stepping motor, which is characterized by creating a current having an amplitude.