JPH0675636A - Advance angle controller - Google Patents

Abstract

PURPOSE:To prevent the cost from being increased due to the increase of man- hours for adjustments by electrically adjusting the phase shift between an encoder and an excitation phase. CONSTITUTION:The encoder 2 outputs signals of phases A and B corresponding to the angle of rotation of a pulse motor 1 and a comparator 3 classifies cases corresponding to the signal levels of the phases A and B. Then the pulse motor 1 is rotated in microsteps and the phase shift quantity is detected from the microstep feed quantity up to the point of time of changes of the case-classified signals. On the basis of the phase shift quantity, a controller 4a calculates correction values for currents supplied to the respective phases of the pulse motor 1 and corrected current values are supplied to the pulse motor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an advance angle control device for accurately controlling the rotation angle of a pulse motor, such as a floppy disk drive device.

[0002]

2. Description of the Related Art For example, a hard disk drive device,
In a floppy disk device, a pulse motor having an encoder attached externally is used as an actuator for positioning a magnetic head. As described above, by adding the encoder to the pulse motor, the current position of the movable portion of the pulse motor can be fed back, and the seek operation can be performed at higher speed.

FIG. 4 is a block diagram showing an example of a conventional device. When a lead angle is designated from the controller 4 to the excitation phase selection circuit 5, the excitation phase selection circuit 5 designates an excitation phase and current amplification is performed. The pulse motor 1 is driven via the circuit 6.

An encoder 2 is attached to the shaft of the pulse motor 1, and the phase differs by 90 ° depending on the rotation angle of the pulse motor 1, as shown in FIG.
The phase and B phase signals are output. This signal is generated by the comparator 3 based on the signal levels of the A phase and the B phase to generate the signals shown in FIGS. 5B to 5E, which are supplied to the controller 4 to perform the feedback control.

Thus, in order to perform the advance angle control by knowing the rotation angle of the pulse motor 1 based on the output signal of the encoder 2 and performing feedback control thereof, the relative phase between the excitation phase of the pulse motor 1 and the encoder 2 is controlled. If the positions do not match exactly, the movement time will differ due to the difference in the movement direction,
It may not be possible to stop at the target step.

Therefore, conventionally, when the excitation phase of the pulse motor 1 and the position of the external encoder are displaced, the relative position of the movable part of the pulse motor 1 and the scale part of the encoder 2 can be monitored by the output signal of the encoder 2. By watching and adjusting mechanically, I was trying not to be affected by the deviation.

[0007]

However, such a conventional adjustment method has a problem that the adjustment man-hour is increased and the cost is significantly increased because the position adjustment of the micrometer order is required.

The present invention has been made in view of such a situation, and changes the balance of the currents supplied to the excitation phase in accordance with the electrically detected position shift amount and the moving direction to change the phase of the encoder and the excitation phase. By electrically adjusting the deviation, the influence of the positional deviation is eliminated, and the cost increase due to the increase of the adjustment man-hour is prevented.

[0009]

In order to solve such a problem, the advance control device according to the present invention determines the excitation phase of the pulse motor based on the signal sent from the encoder for detecting the rotor position of the pulse motor. In a lead angle control device that controls the rotation of a pulse motor by controlling the supplied current, a phase shift detection unit (controller 4a) that detects a phase shift between an encoder and an excitation phase, and a phase shift amount according to the amount of phase shift. And a current distribution amount calculating means (controller 4a) for calculating an optimum distribution amount of the current supplied to the excitation phase.

[0010]

The encoder 2 outputs A-phase and B-phase signals corresponding to the rotation angle of the pulse motor 1, and the encoder 3 separates the signals according to the states of the A-phase and B-phase.
After that, the pulse motor 1 is micro-step fed,
The amount of phase shift is detected from the micro-step feed amount up to the time when the signals are divided in the above case. Based on the phase shift amount, the controller 4a calculates the correction value of the current supplied to each phase of the pulse motor 1, and the corrected current value is supplied to the pulse motor 1.

[0011]

1 is a block diagram showing the construction of an embodiment of an advance angle control device according to the present invention, in which the same or corresponding parts as in the conventional example are designated by the same symbols and their explanations are omitted. In this device, the controller 4a serving as the phase shift detecting means is capable of correcting the current value of the A phase and the current value of the B phase with respect to the current amplifier circuit 6a.

By exciting a certain phase of the pulse motor 1, for example, the a phase, the pulse motor 1 rotates, a signal indicating the rotation angle is output from the encoder 2, the signal is judged by the comparator 3, and the judgment is made. Signal is supplied to the controller 4a.

The controller 4a monitors the output supplied from the comparator 3 and, while monitoring the output supplied from the comparator 3, drives the pulse motor 1 in a constant step width ΔX0 (for example, 1 phase) from the a phase to the b phase.
μm) for micro-step feed.

At this time, the controller 4a stores the microstep feed number n at the time when any of the outputs from the comparator 3 changes. Then, between the actual movement amount, that is, the phase shift amount ΔP and the step size ΔX0,
From the self-positioning characteristics of the pulse motor 1, ΔP = ΔX0
Since there is a relationship of n, the phase shift amount ΔP is obtained.

When the phase shift amount is obtained, the controller 4a then calculates the optimum current value based on the moving direction and the excitation phase. FIG. 2 is a graph showing a current table address and a current value corresponding to the address. When no signal is supplied from the controller 4a to the current amplifier circuit 6a, with respect to the rotation angle of the pulse motor 1 shown on the horizontal axis, Figure 2
The current of the value indicated by the black circle is supplied.

However, as described above, the phase shift amount ΔP
If there is, the current needs to be a value corrected by the amount of phase shift. Since the phase shift amount can be detected as described above, the controller 4a corrects the signal for correcting the address of the excitation phase designation signal supplied from the excitation phase selection circuit 5 to the current amplification circuit 6a by the phase shift amount ΔP.
It is output as an A-phase current value and a B-phase current value for a.

As a result, the current amplification circuit 6a corrects the address signal designating the excitation phase supplied from the excitation phase selection circuit 5 by the signal supplied from the controller 4a. That is, the address signal supplied from the excitation phase selection circuit 5 is corrected by ΔP as shown in FIG.
The corrected address signal is supplied to a current table (not shown) in the current amplifier circuit 6a.

Therefore, in the forward direction, the current having the value indicated by the white circle in FIG. 2 is supplied to the excitation phase of the pulse motor 1, and in the reverse direction, the current having the value indicated by the square is supplied to the excitation phase of the pulse motor 1. To be done.

In this way, the address signal supplied to the current table is corrected by the A-phase current value and the B-phase current value obtained by the controller 4a based on the phase shift amount. The corrected current value is aα and c-phase current values are iα, b-phase and d-phase current values are iβ, and when the forward direction is taken as an example, this value is iα = Imax · cos ( 45 ° + ΔP) iβ = Imax · sin (45 ° + ΔP)

FIG. 3 shows that Imax is 141 mA and ΔP = -1.
The current value obtained when 0 ° is shown. The current thus obtained is supplied to the pulse motor 1 from the current amplifier circuit 6a, so that the pulse motor 1
Even if the excitation phase and the position of the encoder 2 are deviated, it is electrically corrected.

[0021]

As described above, in the advance angle control device according to the present invention, the phase shift between the encoder and the excitation phase is detected, and the optimum current distribution is performed according to the phase shift amount.
Since the current is supplied to the pulse motor, there is no need to mechanically perform phase alignment between the encoder and the excitation phase, and there is an effect that the pulse motor can be rotated with a constant moving time and speed regardless of the moving direction.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a graph showing a relationship between an address signal supplied to a current table address and a current supplied to a pulse motor.

FIG. 3 is a diagram showing a current supplied to each excitation phase of a pulse motor.

FIG. 4 is a block diagram showing a configuration of a conventional example.

FIG. 5 is a waveform diagram showing an encoder output signal waveform and a comparator output signal waveform.

[Explanation of symbols]

 1 pulse motor 2 encoder 3 comparator 4, 4a controller 5 excitation phase selection circuit 6, 6a current amplification circuit

Claims (1)

[Claims] 1. An advance angle control device for controlling rotation of the pulse motor by controlling a current supplied to an excitation phase of the pulse motor based on a signal sent from an encoder for detecting a rotor position of the pulse motor. A phase shift detection unit that detects a phase shift between the encoder and the excitation phase, and a current distribution amount calculation unit that calculates an optimum distribution amount of the current supplied to the excitation phase according to the phase shift amount. An advance angle control device characterized by being provided.