JP2918742B2 - Drive control device for stepping motor - Google Patents

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.

[0002]

2. Description of the Related Art FIG. 5 shows a general configuration of a drive control device for a stepping motor. In FIG.
A predetermined number of drive pulse signals (Pi)
When the driver 20 outputs the rotation direction designating signal (forward direction FW, reverse direction RV), the driver 20 outputs a phase switching excitation signal to the stepping motor 30, and drives the stepping motor 30 to rotate in the designated direction. The rotation speed is determined by the drive pulse signal (P
The frequency is determined by the frequency i), and the rotation speed (angle) is determined by the number Pi of the drive pulse signals.

The use of the stepping motor 30 and the drive control devices (10, 20) makes it possible to move and position various loads with a predetermined speed diagram and with high accuracy. Because of the open loop, the device can be simplified.

For example, when the load is a carrier of a printer, if the load is moved in the forward direction FW from the rotational drive start position ST to the rotational drive end position SP shown in FIG. Clear printing can be performed in the effective area L. The same applies to the reverse direction RV. At this time, the number of drive pulse signals input from the control device 10 to the driver 20 is Pi.

If the load or power supply voltage fluctuates, for example, the correspondence between the number Pi of the input drive pulse signals and the rotation speed (angle) of the stepping motor 30 may be lost, that is, the motor may lose synchronism. . Therefore, overrun detectors 1 and 2 are provided outside the print effective area L to automatically detect a step-out phenomenon. Therefore, forward FW (reverse RV)
If the overrun detector 2 (1) is turned ON despite the addition of the set number Pi of the drive pulse signals for the movement, the step-out on the overrun side can be detected. Incidentally, the step-out of tio over <br/> Trang side can be detected on the opposite side of the overrun detector 1 (2) at the next turning movement.

[0006]

However, according to the above-mentioned conventional structure, the arrangement positions of the overrun detectors 1 and 2 have some restrictions on the layout. It is very difficult to detect the key. In addition, when used in the above-mentioned printer, it is very difficult to determine them from the printing state during operation.
In addition, overruns and short runs increase cumulatively. Therefore, there is an inconvenience that the user notices the condition only after picking up the printed paper. On the other hand, there is a case where there is no problem even if a few lines out of all the lines are displaced a little in the left-right direction. When there is
Since the printer is automatically stopped, the printing work efficiency is reduced. These problems cannot be solved even if the overrun detectors 1 and 2 are carefully set with great effort and time.

An object of the present invention is to provide a drive control device for a stepping motor capable of automatically detecting a step-out phenomenon during a previous drive, and automatically correcting an overrun or a short run after the current drive to accurately rotate the drive. Is to provide.

[0008]

A drive control device for a stepping motor according to the present invention includes a control device for outputting a drive pulse signal, and a driver for controlling the rotation of the stepping motor by inputting the drive pulse signal. A stepping motor drive control device, wherein the encoder outputs a rotation angle equivalent signal connected to the stepping motor, a start position detecting means for detecting a drive start position based on the output signal of the encoder, and an output signal of the encoder. Actual drive end position detecting means for detecting an actual drive end position based on the drive start position detected by the start position detecting means from the number of drive pulse signals output from the control device to the driver and the output signal of the encoder. A target end position calculating means for calculating a target drive end position as a reference; Determining means for comparing the actual drive end position with the calculated target drive end position to determine the presence or absence of step-out; and determining that the actual drive end position is detected when step-out is determined to be the drive start position. The number of correction pulses is calculated from the previous actual drive end position and the target drive end position to calculate the number of correction pulses to be added to or subtracted from the set number of drive pulse signals for current drive that controls the stepping motor to rotate in a different rotation direction from the previous time. Means are provided.

[0009]

According to the present invention having the above-described structure, at the time of starting the rotation drive, the start position detecting means detects the drive start position from the output signal of the encoder. When the rotation drive with the set number of drive pulse signals is completed, the actual end position detecting means detects the actual drive end position from the output signal of the encoder.
Before or after this, the target end position calculating means detects the start position from the set number of drive pulse signals and the output signal of the encoder.
To calculate a target driving end position relative to the detected driving start position above the unit.

Here, the correction pulse number calculating means determines that there is step-out from the comparison between the actual drive end position detected by the determination means and the calculated target drive end position, and determines the next set drive pulse number. The number of correction pulses to be added to or subtracted from is calculated. Therefore, the rotation drive control after this time can be performed properly and accurately without accumulating the overrun or the short run due to the previous step-out.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, this drive control device has the same basic configuration as that of the conventional example (FIG. 5), and has an encoder 35, start position detecting means (11, 12), and actual end position detecting means (11, 12). And target end position calculating means (11, 12)
And determination means (11, 12) and correction pulse number calculation means (1
1, 12) are provided, and the presence / absence of step-out during the previous drive is automatically determined. Then, it is configured so that the rotation drive after this time can be accurately performed.

First, the encoder 35 is connected to the stepping motor 30 as shown in FIG. 1, detects the rotation angle (or the number of rotations), and outputs a signal corresponding to the rotation angle. In this embodiment, one step of the stepping motor 30 generates 16 (0 to 15) 4-bit output signals.

In this embodiment, the stepping motor 30 reciprocates on the carrier of the printer. The printing effective area (width) of the printer is set to L shown in FIG. 2, and the carrier (print head) is moved just by the distance (L) by adding the set number Pi of the driving pulse signal from the control device 10 to the driver 20. Is formed. ST in FIG. 2 is a driving start position and SP
Is a target drive end position. In addition, left in Fig. 2 →
The right side is the forward direction FW.

Next, the start position detecting means includes an encoder 3
2 (FIG. 3), that is, means for detecting the drive start position ST shown in FIG. 2 (FIG. 3), that is, the value FNa1 (RNa2) at the start of drive.
OM12 and ST11 (ST16) in FIG.
Executed in

On the other hand, the actual end position detecting means detects the actual drive end position SP shown in FIG. 2 (FIG. 3) after the actual rotation driving based on the output signal of the encoder 35, that is, the value FNa2 (RNa1) at the end of the actual drive. ), Which also comprises a CPU 11 and a ROM 12 and ST11 (ST1
Executed in 6).

The target end position calculating means calculates the number Pi of drive pulse signals required for moving the carrier by the effective printing width L, the output signal of the encoder 35, that is, the form of the output signal (the above 4 bits). From the target drive end position SP based on the drive start value FNa1 (RNa2) detected earlier, that is, the target drive end value FNc.
2 (RNc1) ｛FNc2 = FNa1 + (Pi ×
16) [RNc1 = RNa2- (Pi × 16)]}, which comprises the CPU 11 and the ROM 12,
This is executed in T12 (ST17). This calculation is
Since the set number (Pi) of the drive pulse signals is predetermined, the value FN at the start of driving in ST11 (16) is determined.
It may be executed immediately after detecting a1 (RNa2).

The above values FNa1, FNc2, FNa2
(RNa2, RNc1, RNal) are temporarily stored in the RAM 13.

Here, the determination means determines the detected actual drive end position [actual end value FNa2 (RNa1)] and the calculated target drive end position [target end value FNc2.
(RNc1)] to automatically determine whether or not the stepping motor 30 has stepped out based on the same isomer.
CPU 11 and ROM 12 executing T13 (ST18)
Consists of In ST13 (ST18), if a YES determination is made, there is no step-out, and if a NO determination is made, it is determined that there is step-out.

The means for calculating the number of correction pulses includes a CPU 1
1 and the ROM 12, and when it is determined by the determination means that there is step-out, the detected actual drive end position [F in FIG.
Na2 (RNa1 in FIG. 3)] as the current rotational drive start position, and a rotational direction RV different from the previous drive [FW (RV)].
In (FW), the number of correction pulses △ FPn (ｎRPn) to be added to or subtracted from the set number Pi (Pi) of the current drive pulse signal for rotationally driving and controlling the stepping motor 30 is obtained [ST
15 (ST20)]. When no step-out occurs, the number of correction pulses △ F
Pn (△ RPn) is zero (0) [ST14 (ST1
9)].

That is, in FIG. 2, the value at the time of the target end when the previous drive in the forward direction FW shown in FIG.
Although it should be c2, the value at the time of actual termination due to overrun due to step-out is FNa2 as shown by the solid line in FIG.
In this case, if the drive pulse signal of the set number Pi is added this time from the actual end position (FNa2) and the current drive is performed in the reverse direction RV, it is not possible to return to the initial drive start position ST. Therefore, by adding the number of correction pulses △ FPn shown in (B), it is possible to accurately return to the initial drive start position ST as shown by the two-dot chain line in (C). (B) and dotted line (C)
The same applies to a seat run indicated by a dashed line. Further, the same applies to the case where the previous time shown in FIGS. 3A to 3C is the reverse direction RV and the current time is the forward direction FW.

Each of the above means corresponds to the R
The correction program shown in FIG. 4 stored in the OM 12 is executed by the CPU 11 in a timely manner.

Next, the operation will be described. Drive start position ST
When driving in the forward direction FW from [FIG. 2A], FIG.
YES is determined in ST10. At the same time, the control device 1
From 0, the set number Pi of the drive pulse signal is output to the driver 20 at a predetermined frequency, and the driver 20 starts rotating the stepping motor 30.

Here, the start position detecting means (11, 12)
Detects the drive start position (starting value FNa1) in FIG. 2 from the output of the encoder 35, that is, reads the value FNa1 and temporarily stores it in the RAM 13 (ST11). When the driving is completed, the actual end position detecting means (11, 12)
An actual driving end position (actual end value FNa2) is detected (ST11). In FIG. 2B, a solid line indicates an overrun, and a dotted line indicates a short run.

The target end position calculating means (11, 1)
2) In ST12, a target drive end position (value FNc2 at the time of target end) is calculated. Then, the determination means (1
1, 12) is, the value of the FN a fact at the end of this value FNc2
Then, the presence or absence of step-out is determined by comparing with Step 2 (ST13).

If the determination in ST13 is YES, there is no step-out, so the number of correction pulses ΔFPn is set to zero (0).
When the determination is O, the correction pulse number calculation means (11, 12) automatically calculates the correction pulse number △ FPn (ST15). The value of the number of correction pulses △ FPn becomes a positive value in the case of overrun shown by a solid line in FIG.
In the case of the short run indicated by the dotted line, the value is negative.

Thus, the current reverse direction R shown in FIG.
At the time of driving at V, the control device 10 sets the set number Pi of the driving pulse signal to the number of correction pulses 時 に FPn obtained at the previous driving.
Is added and subtracted and output to the driver 20. Therefore, it is possible to reliably return to the return position (ST) as shown in FIG.

The same applies to the case where the previous time is the reverse RV drive and the current time is the forward FW drive shown in FIG.

According to this embodiment, the encoder 35, the start position detecting means (11, 12), the actual end position detecting means (11, 12), and the target end position calculating means (1)
1, 12), determination means (11, 12) and correction pulse number calculation means (11, 12), and compares the target drive end position with the actual drive end position during the previous drive to determine if there is a step-out. The number of correction pulses for the current drive is automatically determined, and the set number of drive pulse signals for the current drive (Pi) is calculated.
Since the number of correction pulses is adjusted to
Even if there is a step-out during the previous drive, the overrun or short run is not carried over after the current drive, and the drive after this time can be performed accurately.

Further, since the encoder 35 is configured to output a 4-bit divided signal for one step of the stepping motor 30, it is possible to accurately detect whether or not the step-out occurs.

The values FNc2 and RNc1 at the end of the target
Is calculated on the basis of the actual drive start position (FNa1, RNa2) detected from the output signal of the encoder 35, and therefore has a wide adaptability that matches actual driving.

Since the step-out determination is performed based on the drive pulse signal and the output signal of the encoder 35, there is no need to provide the conventional overrun detector (1, 2). Therefore, the size of the printer can be further reduced.

[0032]

According to the present invention, the encoder, the start position detecting means, the actual end position detecting means, the target end position calculating means, the determining means and the correction pulse number calculating means are provided, and the target driving end position is determined during the previous driving. And the actual drive end position are compared to automatically determine the presence or absence of step-out, calculate the number of correction pulses for the current drive, and add or subtract the number of correction pulses to the set number of drive pulse signals for the current drive Therefore, even if there is a step-out during the previous drive, the overrun or short run is not carried over after the current drive, and the drive after this time can be performed accurately.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is also a diagram for explaining an operation (1).

FIG. 3 is a diagram for explaining the operation (2).

FIG. 4 is a flowchart for explaining operations (1) and (2).

FIG. 5 is a block diagram showing a conventional example.

FIG. 6 is a diagram for explaining the operation and problems of the conventional example.

[Explanation of symbols]

1, 2 overrun detector 10 control device 11 CPU (start position detecting means, actual end position detecting means, target end position calculating means, discriminating means, correction pulse number calculating means) 12 ROM (start position detecting means, actual end position) Detection means, target end position calculation means, determination means, correction pulse number calculation means) 13 RAM 20 driver 30 stepping motor 35 encoder

Claims (1)

(57) [Claims] A control device for outputting a drive pulse signal;
A driver for controlling the rotation of the stepping motor by inputting a drive pulse signal; and an encoder for outputting a signal corresponding to a rotation angle coupled to the stepping motor; and an output signal of the encoder Start position detection means for detecting a drive start position based on the following: an actual end position detection means for detecting an actual drive end position based on an output signal of an encoder; and the number of drive pulse signals output from the control device to a driver. From the start signal and the output signal of the encoder .
Whether a target end position calculating means for calculating, by comparing the detected actual driving end position and calculated target driving end position of the step-out target drive end position relative to the detected driving start position I Determining means for determining whether a step-out has occurred, and using the detected actual drive end position as the drive start position as a drive start position to control the stepping motor to rotate in a different direction from the previous drive pulse signal for the current drive. A drive control device for a stepping motor, comprising: correction pulse number calculation means for calculating a correction pulse number to be added or subtracted from a set number from a previous actual drive end position and a target drive end position.