JPS6055895A - stepping motor - Google Patents

Abstract

PURPOSE:To reduce an hysteresis error by similarly performing the similar exciting step of clockwise rotation also to the case of counterclockwise rotation. CONSTITUTION:When a pulse motor wich is stopped in the excitation of phases A and B is excited in phases B and C, one preceding phase BD from the phase to be stopped is excited, and the phase BC to be again stopped is excited in a range that does not exceed the position to be stopped at the position of the rotor of a stepping motor. Thus, an error due to the difference of the exciting steps owing to the difference of rotating directions can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reducing the difference in static position of a stepping motor depending on the driving direction (hereinafter referred to as hysteresis error).

Stepping motors are widely used as actuators for digital control because of their high positioning accuracy. On the other hand, in recent applications of stepping motors to 0 Atfi devices, miniaturization of the step angle is being sought as the number of positioning increases. However, due to the miniaturization of the step angle, the step angle shielding error and the hysteresis error have become relatively large and cannot be ignored. In particular, when it is necessary to repeatedly and precisely stop at the same field θ', such as in a magnetic recording device, it is desirable that the hysteresis error be as small as possible.

The causes of hysteresis errors are mainly due to frictional loads and due to differences in the excitation process even at the same stationary position depending on the driving direction.

Conventionally, attempts have been made to reduce these errors by improving the performance of the stepping motor itself. I haven't been able to come up with anything that satisfies me, including the cost.On the other hand, I can't think of any countermeasures to reduce the hysteresis error due to the drive method.

The present invention completely improves the method of driving a stamping motor in order to solve these problems.

An example of the present invention will be described below using two-phase excitation wY motion of a two-phase stepping motor.

The 11th line 1 is a +111 simple diagram of a two-phase stepping motor. 1 is a stator, 2 is a rotor, 3 is an excitation winding, 4
, 5, '6, and 7 are terminals of each winding.

Group 2 shows an example of normal excitation of the stepping motor shown in FIG. 2A, 2B, 20 and 2D are the terminal' voltages of FIG. 1, 4.5 and 6.7, respectively.

In section a, current flows in the direction from 4 to 5 and from 6 to 7, and the rotor moves to the position indicated by arrow 8 in FIG. In section 1, current flows in the directions 5 to 4 and 6 to 7, and the rotor moves to the position indicated by arrow 9 in FIG. Thereafter, similarly, in section IJIC, the rotor moves to the position indicated by arrow 10 in FIG. 1, and in section d, the rotor moves to the position indicated by arrow 11 in FIG. The stepping motor rotates clockwise by the above operations, and rotates counterclockwise by performing the entire opposite operation.

Considering the change in the excitation current when the rotor comes to rest due to the excitation of the section A, the current between 4 and 5 is reversed when the rotor reaches the section A from the section A clockwise. On the other hand, when going counterclockwise from section C to section C, the current between 6 and 7 is reversed. This difference in the excitation process is one of the causes of hysteresis error. Therefore, if the entire excitation process is affected in both the timewise and counterclockwise cases, the hysteresis error can be completely reduced.

FIG. 3 is an example of excitation by the driving method of the present invention. 3A
, 3B, 30.3D are the voltages at terminal 4°5.6.7 in FIG. The initial rotor position is indicated by arrow 8 in FIG. 1, and is driven to rest at arrow 9. Section θ in Figure 3
1, the current flows from 4 to 5 and from 6 to 7 in FIG. Next, by switching to the full excitation section f, the current changes from 5 to 4 and from 6 to 7, and the rotor starts moving in the same direction as the arrow 9. Immediately after that, cut to the excitation of section g of the arrow!
11, the rotor moves to the position indicated by the arrow 10. At this time, the rotor is excited as shown in section n in FIG. 3 so that the rotor comes to rest in the direction of arrow 9 at an appropriate time when the rotor position does not exceed the position of arrow 9. In the final excitation switching, the current direction changes from 7 to 6 to 6 to 7 29, which is a counterclockwise excitation switching, i.e.
This is the same as the switching from section C to section S in FIG. Therefore, it is possible to reduce errors caused by differences in the excitation process due to differences in rotational directions.

In addition, by performing this operation in both clockwise and counterclockwise directions, hysteresis errors caused by other causes can also be reduced.

Next, FIG. 4 shows the changes in torque due to this driving method. In this figure, the horizontal axis is the rotation angle, and the vertical axis is the torque, 12 is the torque corresponding to the excitation in section a in the figure, and 13 is the section IJ in the same figure.
The torque curve 14 corresponds to the excitation in section C in the same figure, and the torque curve increases by 6 with respect to the excitation of Ib.

During the excitation in section a, the rotor is at rest at a stable point 15 on the torque curve in FIG. In the case of the J drive, when the excitation of the section S is switched, the rotor torque becomes 16 points on the torque curve 16 in FIG. 4, and the rotor rotates in the forward direction and stops at a stable point 20.

On the other hand, in the driving method according to the present invention, the stable point 15 twisting section f
Due to the excitation vd, torque is applied at 16 points on the torque curve 13, and the rotor rotates in the forward direction. The rotor starts rotating
When the current is reached and the excitation is started in section g, the torque is 1 in Fig. 4.
The rotor torque reaches point 18 on the torque curve 13, and as the rotor rotates, it moves on the torque curve to point 19, and then when the section to be held still is fully excited, the rotor torque reaches point 19 on the torque curve 13. As it rotates, it decreases and comes to rest at a stable point 20.

According to this method, the torque applied to the rotor is smaller than in the normal method, so the acceleration of the rotor is slower. Therefore, the amplitude of the attenuation JHDrv that occurs near the stable point 20 becomes smaller, and the time it takes to stay at 1 becomes shorter.

Although the example of the two-phase excitation drive sound of a two-phase stepping motor has been described here, the same applies to other stepping motors and excitation methods.

As explained above, the present invention! If the oscillating force method is used, the hysteresis error of the stepping motor can be reduced by 1, and the time used for damping vibration during positioning is also shortened.Therefore, a good IEU is required. 11 The application of a stepping motor to the R9i cannot be fully realized.Also, since it can be realized only by switching the excitation phase, it is possible to do so by adding only the means to create the timing for switching all the excitation phases while maintaining the conventional oscillation circuit. ”: It can be easily achieved. Stepping motor 41,4j j
Even if iL is different, it can be handled by adjusting only the excitation phase switching timing.

If the present invention is used in the stepping motor for the actuator of the 24 city air recording device, the trunk density can be higher than that of the conventional drive method, and it is effective for increasing the thickness of the interiors 6 and 4.

[Brief explanation of the drawing]

Figure 1 (g, sil) Stepping Tanabata Simple Figure 2 is a diagram showing all of the following! IjJJ magnet'+t'J
The figure shows an example of excitation by the 1-drive 1flJ method of the present invention. Figure 4 shows an example of torque change by the 1-drive method of the present invention. 1. Stator 2. Rotary rotor... Vol. Lines 4, .5, 6.7... Winding terminals 8-11... Rotor rest positions 12-14... Torque curve 2A at each rest position,
2E, 2C! , 2D, 3A, 3B, 30° 3D...The voltage at each winding terminal or more

Claims (1)

[Claims] In positioning and sterilization of a stepping motor, the phase to be brought to a standstill is energized, and immediately after starting, the phase one ahead of the phase to be brought to a standstill is energized, and the position of the rotor of the stepping motor is brought to a standstill. A stepping motor characterized in that the phase to be brought to a standstill is once again excited by 1 mm within a range that does not exceed the position to be brought to a standstill, and then brought to a standstill.