JP2642224B2 - Stepping motor phase matching control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] Rotating a rotor to a required position from a stopped state 1.2
A phase matching control method for a stepping motor that performs phase alternation excitation is intended to ensure that the rotor can be rotated to a target position reliably and quickly during phase matching. One phase and two phases that match are repeatedly and alternately excited in a short cycle, and when the rotor sufficiently approaches those phases, the desired one or two phases are excited to stop the rotor. .

[Industrial applications]

The present invention relates to control of motor combination (rotor pull-in) at the time of power-on or the like in an apparatus using a stepping motor as a driving means, and particularly to reliably rotate a rotor to a required position from a stopped state. The present invention relates to a phase matching control method for a stepping motor.

A stepping motor is used as a driving means in a field requiring high-precision positioning, and when used in an open loop, it is necessary to particularly control the rotation of the rotor.

[Conventional technology]

Conventionally, phase matching control of a stepping motor has been performed by exciting a target phase (for example, A phase) for a certain period of time to rotate the rotor to a required position.

However, in this method, when the rotor is initially stopped at a position 180 ° out of phase with respect to the phase to be excited, the rotor receives exactly the same rotational torque in the forward and reverse rotation directions. As a result, it is not possible to perform normal rotation or reverse rotation, and the motor may remain stopped.

FIG. 3 is a diagram for explaining the problem of the prior art. In FIG.
The stator 10 and the rotor 11 are shown in a form extended in the lateral direction.

When the rotor 11 is stopped by rotating to the position of R0 in the left direction or the position of R0 'in the right direction, the excitation to the A phase is performed.
In this case, first, when the rotor 11 is at the position of R1 of the B phase,
Since the leftward force acts stronger than the rightward direction, the rotor 11 moves leftward.

However, if the rotor 11 is at the position of the C phase, that is, R2 when the A phase is excited, the rotational torques acting in the left direction and the right direction are the same, and the rotor 11 may not be able to move to either smoothly.

Further, the prior art has the following problems. As shown in FIG. 4, in the matching, if the moving distance of the rotor is large, a larger rotational torque is generated in the rotor,
It will vibrate due to overshoot. That is, the vibration converges relatively quickly at the rotor movement distance X1 of 1 step or 0.5 step, but when the rotor is rotated by the phase matching control, the movement distance of the rotor may be longer like X2. Because of the large rotational torque, the vibration becomes large, and it may take a long time for the vibration to converge.

In particular, when the rotational torque is large, the motor is not returned to the target position, and the next stable point (for example, when the phase difference is 360 degrees ahead A
Phase).

[Problems to be solved by the invention]

As described above, according to the conventional control method, the rotor may not be able to move smoothly to the target phase during the retraction operation. However, there is a problem that a response cannot be made to a normal rotation command (step out).

Further, if one phase is excited continuously for a long time to stop a large vibration due to the movement distance X2 as shown in FIG. 4, excessive heat generation may occur, which may cause a failure.

The present invention seeks to solve the above problems, and at the time of matching,
It is an object of the present invention to be able to rotate a rotor to a target position reliably and quickly.

[Means for solving the problem]

 FIG. 1 is a diagram illustrating the principle of the present invention.

In the phase matching control method for a stepping motor according to the present invention, two adjacent phases including the target phase are repeatedly and alternately excited in a short cycle, and the target phase is set when the rotor sufficiently approaches those phases. Excitation stops the rotor.

For example, in a four-phase motor of A to D phases that performs 1-2 phase alternating excitation, when performing phase adjustment to the A phase, the DA phase is made much shorter than the conventional excitation time by step S21 shown in FIG. Excite only for a time. Next, in step S22, the target A phase is similarly excited for a short time. Step above
Repeated a predetermined number of times by the determination in S23, and if the rotor has sufficiently approached the vicinity of the target A-phase,
The A phase is finally excited by S24, and the rotor is stopped at the A phase position.

[Action]

By exciting adjacent phases in sequence, even if the rotor is initially stopped at a phase difference of 180 °, the rotor cannot be rotated and the rotor can be reliably rotated to the target phase position. .

At this time, by exciting the adjacent phases repeatedly and alternately with a very short cycle, the rotor can be gradually brought closer to the target position, so that overshoot and vibration are prevented, and The rotor can be reliably stopped at the position.

〔Example〕

FIG. 2 is a diagram showing the phase excitation timing and the movement of the rotor according to the embodiment of the present invention.

Hereinafter, an example of a four-phase stepping motor of A to D phases that performs 1-2 phase alternating excitation will be described. When the rotor is first stopped at the BC phase position, the A phase matching is performed.

As shown in FIG. 2, first, the DA phase, which is the next phase to the A phase, is excited for a short time. Since the rotor is in the BC phase,
Both receive the same rotational torque and remain in the BC phase. next,
When the target A-phase is excited for a short time, the rotor is attracted to the A-phase having the smaller phase difference. After that, DA again
The phases are excited, and similarly, the excitation of the DA phase and the excitation of the A phase are alternately repeated in a short cycle. As a result, the rotor is gradually drawn to the phase A, and reaches the position of the phase A without any vibration due to inertia and stops.

Here, the excitation timing and the like are determined by the load of the device. For example, a conventional device that performs phase matching with continuous excitation of less than 100 ms
Excitation on the order of s or 1 ms is repeated alternately in adjacent phases. Of course, the present invention can provide a sufficient effect even if the value is not this value. To determine how many rotations are repeated, conduct a test or the like in an environment suitable for the usage conditions, determine the worst number of times required for the rotor to sufficiently approach the target position, and take an appropriate The design value may be obtained by adding a margin. In this example, the excitation was repeated 50 to 60 times.

〔The invention's effect〕

As described above, according to the present invention, the rotor can be reliably rotated to the target position when the stepping motors are aligned, so that the displacement can be prevented particularly when used in an open loop. And the reliability of the device can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention, FIG. 2 is a diagram illustrating the phase excitation timing and the movement of the rotor according to the embodiment of the present invention, and FIG. 3 and FIG. is there. In the figure, reference numeral 10 denotes a stator, and 11 denotes a rotor.

Claims (1)

(57) [Claims] In a phase matching control method for a stepping motor for performing one- or two-phase alternating excitation for rotating a rotor to a required position from a stopped state, an adjacent one-phase and a two-phase including a target phase are short-cycle. A step of exciting a desired phase or two phases and stopping the rotor when the rotor sufficiently approaches those phases.