JPS62171498A - Exciting system for stepping motor - Google Patents

Abstract

PURPOSE:To improve the positioning accuracy and to reduce a backlash of a step motor by superposing a stopping pulse with a stopping constant voltage and applying it to an exciting winding. CONSTITUTION:A controller 1 receives an external input, decides an exciting phase by the input, and turns ON a driving transistor corresponding to the phase. The transistor is continued to be ON at stopping time. A sub-controller 6 receives an external input to obtain the stopping position of a stepping motor 3. It outputs a pulse for turning a stopping pulse driving transistor 7 at the moment that the motor is stepped at the obtained stopping position. Accordingly, the constant voltage applied from a driving transistor 2 and the stopping pulse applied from the transistor 7 are superposed to be applied to the winding 4 of a target exciting phase.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an excitation method for a step motor, and more particularly to various positioning methods for magnetic disk drives and the like in which positioning accuracy during stoppage is important.

[Prior art]

In the conventional step motor excitation method, as shown in Fig. 3, the controller (1) receives an instruction signal from the outside,
An excitation phase is determined and a driving transistor (2) connected to the excitation phase is made conductive. As a result, when an excitation current flows through the excitation winding of the step motor (,?), the rotor (5) rotates so as to be attracted to this excitation phase.

The stopping operation is performed by fixing the excitation phase, that is, by continuing to allow current to flow through the drive transistor (2), and is basically the same method as when driving. This state continues until the excitation phase drive transistor is turned off and the other excitation phase drive transistors are switched on.

[Problem that the invention seeks to solve]

As described above, in the conventional step motor drive system, the rotor is stopped by the excitation current used when driving the rotor, so when there is a load, the following problems may occur.

l) Vibration at the target step position due to the inertia of the load, as shown in Figure 7.

2) Punch crash in the stopping position due to friction, etc. (variation in position when rotating in the opposite direction and stopping at the same position).

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to reduce pan crashes when the step motor is stopped.

[Means for solving problems]

In addition to the conventional excitation method when stopping a step motor, the present invention also superimposes a stop pulse of a higher voltage on the fixed excitation voltage for stopping, and if necessary, applies the pulse multiple times. This is to stop the step motor.

[Effect]

In the present invention, the stop pulse applied superimposed on the normal constant voltage for stopping uses a voltage higher than the constant voltage, so that the rotor can be more strongly attracted to the target step position. Also, if necessary, by adding multiple pulses,
Corresponding to the photographing at the step position, it is possible to further shorten the time it takes for damage to settle and improve positional accuracy.

〔Example〕

Hereinafter, the present invention will be explained along with examples thereof.

In FIG. 1, a sub-controller (6) and a stop pulse drive transistor (7) are provided in parallel with a conventional controller (1) and a drive transistor (2). The sub-controller (6) is connected to the external input like the controller (1), and if necessary, the controller (
1) is also connected. Further, the stop bus/l/bus driving transistor (wa) is connected to the stop pulse power source v'. The emitter outputs of both transistors (2) and (7) are superimposed in a mixer (7) and the excitation winding #(
(Hiroshi).

Next, the operation will be described. As in the conventional case, the controller (1) receives an external input, determines the excitation phase accordingly, and turns on the driving transistor corresponding to the excitation phase. and,
When stopped, the driving transistor is kept on.

The sub-controller (6) also receives an external input (and a signal from the controller (1) if necessary) to determine the stop position of the step motor (3). Then, at the moment of stepping to the determined stop position, a pulse is output that turns on the stop pulse driving transistor (7).

Therefore, the constant voltage applied from the drive transistor (2) and the stop pulse applied from the stop pulse drive transistor (7) are superimposed, and the target excitation phase winding (l
I). In this case, a pulse waveform diagram taking the first phase as an example is shown in FIG.

As described above, in the excitation voltage applied to the excitation winding (lI), a stop pulse is additionally superimposed on the constant voltage for stopping at the moment of stopping, which improves positional accuracy and contributes to reducing backlash and the like. Further, if necessary, the sub-controller (6) may output a pulse multiple times in order to cope with the "vibration at the target step position" shown in FIG. This further reduces the time required for vibration convergence and improves position accuracy.

In the above embodiment, the stop pulse is applied at the leading edge of the constant voltage for stopping of each phase of the step motor, but the power supply
A stop pulse may be placed directly on the .

Further, the superimposition effect in the mixer may be such that the higher level meat input is output, or the meat input may be added.

Further, although the embodiment is an open loop, it can also be applied to a closed loop.

〔Effect of the invention〕

As described above, in the present invention, since the stop pulse is applied to the excitation winding superimposed on the constant stop voltage, it is possible to improve the positioning n degree and reduce backlash and the like.

Therefore, it is extremely effective for open loop systems where puncture crash is a problem, such as carriage positioning of FDD.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of the excitation method of a step motor according to the present invention, Fig. 2 is a waveform diagram of an excitation pulse used in the excitation method of Fig. 1, and Fig. 3 is a configuration diagram of a conventional excitation method of a step motor. Figure 9 is a waveform diagram showing the vibration situation when the step position is stopped.
It is. (1)...Controller, -)...Drive transistor, (3)...Step motor, (G)...Excitation winding,
(j)・Rotor, (A)・Sub controller, (7)・stop pulse drive transistor, (za)・
・Mixer. In each figure, the same reference numerals indicate the same or corresponding parts. Atsushi 1 figure W-) 2 figure Fang 388.

Claims (3)

[Claims] (1) In an excitation method for a step motor in which a constant voltage is fixedly applied to the excitation winding in order to stop the step at a target step position under a load, a step motor is characterized in that a stopping pulse is superimposed when the constant voltage is applied. Motor excitation method. (2) The step motor excitation method according to claim 1, wherein the stopping pulse is applied a plurality of times. (3) The step motor excitation method according to claim 1 or 2, wherein the stopping pulse has a voltage higher than the constant voltage.