JPH01243893A - Step motor controller - Google Patents

Abstract

PURPOSE:To start a step motor properly and quickly, by changing the starting method corresponding to whether stop hold current is flowing or not. CONSTITUTION:When a drive signal based on an input from an external machine is inputted within an interval for holding a stopped mover at a stopping position through a step position holding means M3, driving of the mover is executed immediately through a mover drive means M1. When the drive signal is inputted upon elapse of the holding interval of the stop position holding means M3, an exciting means M2 excites the stop phase of the mover for a predetermined exciting interval before the mover is driven through the mover drive means M1. Thereafter, driving of the mover is executed through the mover drive means M1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stepping motor control device that performs drive control of a stepping motor based on a drive signal.

[Prior Art] In a conventional stepping motor control device, the excitation phases are sequentially excited in a predetermined order to drive the mover by a predetermined amount, and then the stopped excitation phase (stop phase) of the mover is held and excited to stop. The movable element is stopped and held at a position facing the phase. The stopped movable element is activated based on a drive signal created by decoding the keystrokes of an external device such as a keyboard for driving the movable element.

When the mover is started, the stop phase in which the mover has been stopped is once excited for a predetermined period (hereinafter referred to as pre-excitation period) before the excitation phases are sequentially excited, which is called pre-excitation. are being carried out. By this pre-excitation, the movable element is forcibly held in a position facing the stop phase, and then it is sequentially excited in a predetermined order starting from a predetermined excitation phase.

By performing pre-excitation in this way, smooth startup is achieved by preventing uneven rotation during startup and loss of synchronization due to misalignment between the stopped position of the mover and the newly excited excitation phase. are doing. - [Problems to be Solved by the Invention] However, the above-described stepping motor control device is still not sufficient, and the following problems have been pointed out.

If pre-excitation is performed, it is possible to prevent the above-mentioned step-out and the like and obtain a suitable start-up, but a delay corresponding to the pre-movement period m occurs each time the mover is started.

For example, in a stepping motor for carriage feeding in a printing device, each time printing is performed, pre-excitation is performed to maintain the stop position of the carriage (stepping motor), excitation is performed to move the carriage (stepping motor drive), etc.
Carriage (stepping motor) when hitting the printing hammer
Holding and excitation is performed sequentially to hold the stop position. Therefore, when performing continuous printing, each of the above (ii)
I] Magnetism is repeated sequentially, so pre-excitation is performed subsequent to holding excitation. In this way, the holding excitation and pre-excitation for maintaining the carriage stop position are performed successively, so that during continuous printing, the printing speed is slowed down by the amount of pre-excitation.

The present invention has been made to solve the above problems, and its purpose is to provide a stepping motor control device that can suitably and quickly start a stopped stepping motor.

Structure of the Invention [Means for Solving the Problems] In order to solve the above-mentioned problems, the means adopted by the present invention is as shown in the basic schematic diagram of FIG. a movable element driving means M1 for driving the movable element to a predetermined stop position by sequentially exciting the excitation phases of the movable element in a predetermined order; pre-excitation means M2 for exciting the stop phase at the stop position for a predetermined pre-excitation period; and after the mover is stopped at the stop position by the mover driving means M1, the stop phase at the stop position is a stop position holding means M3 for exciting the movable element and holding the movable element at the stop position; and when a drive signal is input within the holding period of the stop position holding means M3, the movable element driving means M1 is immediately executed. and a driving procedure setting means M4 for causing the movable element driving means M3 to be executed subsequent to the pre-excitation means M2 when the driving signal is input after the elapse of the holding period. The gist is the device.

[Function] The stepping motor control device according to the present invention controls a plurality of excitation phases by the movable element driving means M1 in a predetermined procedure over the driving period of the movable element, for example, a one-phase excitation method, 1-2
The movable element is driven by sequential excitation according to a phase excitation method, a two-phase excitation method, etc., and is stopped at a predetermined stop position.

When the movable element is activated, a drive procedure is set by the drive procedure setting means M4. That is, when a drive signal based on an input from an external device or the like is input within the holding period during which the stopped movable element is held at the stopped position by the stopped position holding means M3, the movable element is immediately moved by the movable element driving means M1. Execute the drive.

When a drive signal is input after the holding period of the stop position holding means M3 has elapsed, before the mover driving means M1 drives the mover, the pre-excitation means M2 changes the stop phase in which the mover has been stopped until then. Energize for a predetermined pre-excitation period. Thereafter, the movable element driving means M1 drives the movable element.

Note that the excitation by the mover driving means M1, the pre-excitation means M2, and the stop position holding means M3 may be carried out using currents suitable for excitation of each means, and the currents do not have to have the same value.

[Embodiment] Next, an embodiment in which a stepping motor control device according to the present invention is applied to a typewriter will be described with reference to the drawings. The present invention is not limited to this, but includes various embodiments without departing from the gist thereof.

FIG. 2 is a diagram showing the configuration of a typewriter to which the present invention is applied.

The typewriter 10 prints on paper 40 set on a platen 30 using a print head 20 consisting of a daisy wheel and a print hammer.

The print head 20 is attached to a carriage 70 which is supported by a guide shaft 60 so as to be able to occupy one position along with the print ribbon 50, and characters are selected by a stepping motor 55 for character selection which rotates a daisy wheel. The carriage 70 is driven by a carriage stepping motor 90 via a belt 80, and moves the print head 20 to a predetermined position along the longitudinal direction of the platen 30. or,
The platen 30 is driven by a line feed stepping motor 100 connected via a gear,
0 to a predetermined position. Furthermore, the printing ribbon 50 is
The stepping motors 55, 90, 100, etc. for the printing ribbon winding stellar (not shown) are all four-phase stepping motors, and FIG. 3 illustrates a schematic configuration of the carriage stepping motor 90. As shown in the figure, the stepping motor 90 consists of four excitation phases 90A, 90B, 90C and 90D, and a transistor 90H is connected between each excitation phase and a high voltage terminal VH and a low voltage terminal VL.
, 90L are connected to each other. The base of each transistor is connected to an input/output port 230 of the electronic control circuit 110, which will be described later. Further, the transistors 90a, 90b, 90c and 90d have their collector emitters connected between each of the excitation phases and the ground,
Each base is connected to an input/output port 230.

The above-mentioned stepping motors 55, 90, 100, etc. are driven based on 0N10FF of each transistor controlled by the electronic control circuit 110.

When the transistor 90H is in the ON state and the transistor 9OL is in the OFF state, and the transistors 90a to 90d are controlled to 0N10FF according to a predetermined procedure, each excitation phase is excited by the drive current 1 from the high voltage terminal VH according to the predetermined procedure. , the rotor rotates. Transistor 90H
tfi is in the OFF state, the transistor 90L7') is in the ON state, and when a predetermined transistor of the transistors 9Qa to 90d is turned on, a predetermined excitation phase is excited by the holding current I from the low voltage terminal VL, and the rotor's stop position is Retained.

In addition, signals such as data from the keyboard 105 and signals from various switches, such as a cover open signal and a cover close signal from a cover open/close sensor 140 provided on the power switch 120 and the cover 130, are input to the electronic control unit 110. be done.

The electronic control device 110 described above includes a well-known CPU 200,
ROM210. In addition to the RAM 220, it is comprised of an input/output port 230 that converts input/output signals from the motors, switches, and sensors into signals that can be processed by the CPU 200, and a common bus 240 that connects these.

Next, processing according to the program stored in the ROM 210 of the electronic control unit 110 will be explained based on the flowchart shown in FIG. 4 and subsequent figures.

The flowchart in FIG. 4 is a control routine that schematically shows processing related to printing among the various functions executed by the typewriter 10. First, when the power is turned on, a step 81 (hereinafter simply referred to as Sl) is performed. In the same way for other steps), the initial settings when the power is turned on, that is, the origin detection of the carriage 70 and daisy wheel, the process of setting other stepping motors, etc. to the initial phase, and the resetting of the counter described later, etc. are performed. be exposed. Next, in S2, it is determined whether the counter value of a counter CCA set in a CA operation control routine to be described later is O or not. If 0CA=O is determined to be negative, the process moves to step 84, and if determined to be affirmative, the excitation of all stepping motors is turned off in step 83. Then S4
It is determined whether or not there is a key force from the keyboard 105, and if there is no key force, special operations are performed until the key force is available. If there is key human power, it is determined in S5 whether the key human power is a character/symbol key, and if it is other than a character/symbol key, S5 is performed.
At step 6, processing according to the input key is executed, and the process returns to S2.

If the key is a character/symbol key, the stepper motor 55 for character selection is driven in S7 to set the character corresponding to the character/symbol on the daisy wheel at the striking position of the printing hammer.

After setting the type, the stepping motor 55 is stopped and held by the stop phase holding and excitation. Next, in S8, the printing hammer hits the Digiwheel to complete printing. The completion of the striking of the printing hammer is used as a drive signal S, and at S9, the carriage is fed by a CA operation control routine to be described later. When the carriage feeding is completed, the CA stepping motor 90 is stopped and held by excitation of the stop phase at 814, which will be described later. In the SIO performed in parallel with these S steps, the printing ribbon 50 is wound by driving a stepping motor (not shown), and the stepping motor is stopped and held in the same manner as the CA stepping motor 90. When the process of 310 is completed, the process returns to S2 again. In addition, during the continuous printing period in which the above-described process is continued, a new character selection in S7 is performed even while the carriage is being fed in S9. Immediately after the carriage stops, a new printing hammer of S8 is struck. The period required to hit this printing hammer is 25
Since m5ec is sufficient, when performing the above-described continuous printing, a new drive signal S is issued 25 m5ec after the carriage stops.

FIG. 5(a) is a flowchart of a CA operation control routine that is executed every time the drive signal S of the CA stepping motor 90 is output, and FIG. 5(B) is a counter subtraction that is interrupted every 1 m5ec. The flowchart of the routine, FIG. 6, is a time chart showing the excitation state of each excitation phase (changes in voltage applied to each excitation phase) of the CA stepping motor 90 based on the drive signal S and the processing of each flowchart. .

First, at the time when the drive signal S is issued, it is determined in step 811 of the CA operation control routine whether or not each excitation phase is excited. If it is determined that the current is being energized (maintaining and energizing), it is the continuous printing period described above (time t1 or t3 in FIG. 6), and the process proceeds to S13 without performing the next process of S12.

If it is a continuous printing execution period, in the next step 813, after printing is completed by hitting the printing hammer (88), a predetermined number of pulses, ie, 4 pulses, are outputted to move the carriage 70 by one character. Specifically, the transistor 90L is switched from the ON state to the OFF state, the transistor 90H is switched from the OFF state to the ON state, and the transistors 90a,
90b.

90c and 90d are turned on using a one-phase excitation procedure from transistor 90b. In this way, each excitation phase 90A, 9
08.90C and 90D are sequentially excited by the drive current i for 4 m5ec each, and after the rotor rotates once, it stops at the excitation phase 90Δ (from time t1 to time t2 or from time t3 to time t4 in FIG. 6). In the process of S13, the carriage 70 moves to one character distribution force and stops. Next, at 814, the excitation phase 90A, that is, the stop phase 90A, is held and excited by the holding current IL so that the carriage 70 does not move during printing (next time 88) by hitting the printing hammer, and the rotor is reliably moved to the stop phase 90A. Stop it by facing it. Specifically, the transistor 90H is turned from the ON state to the OFF state, and the transistor 90L is turned OFF.
Switch from F state to ON state (time t2 or t in Figure 6).
4). Note that when the CA stepping motor is held and excited in S14, the type selection stepping motor 55,
Line field stepping motor 100. The chipping motor for winding the printing ribbon is also held and energized.
The wheels, paper 40, and print ribbon are also held stationary. Also, during the process of S13, the next 87 type characters are selected. Thereafter, in S15, a counter CCA for measuring the elapsed time since the stop phase 90A is held and excited is set to 50O, and then in 316, the stop phase 90A is set to 50O.
0A excitation data and the like are written and stored in a predetermined address of the RAM 220. Note that the memory in 316 is updated and retained from the previous one. When the processes up to 816 are completed, the process moves to the next process of the main routine.

On the other hand, if it is determined that each excitation phase is not excited,
This is a case where printing is executed sporadically (time t in Figure 6).
6) In S12, the previous stop phase determined from the excitation data stored in the RAM 220 is pre-excited with the holding current I for a period of 10 m5ec, and the rotor is stopped facing the determined stop phase (the 6 from time t6 to time t7).

Specifically, if the stop phase is the excitation phase 90A, a base voltage is applied to the transistor 90L and the transistor 90a to turn on the transistors 90L and 90a.

Next, the process from 313 to S16 is executed in the same manner as in the case of continuous printing described above, and the process moves to the next process.

The counter subtraction routine shown in Figure 5(b) is 1m5ec.
First, in step 820 of the flowchart, it is determined whether the counter value of the counter CCA set to 500 in S15 is O or not. If 0CA=O is affirmatively determined, the process is temporarily terminated without performing any processing, and the process waits until the counter 1 shift is newly set in OCA in the CA operation control routine described above. On the other hand, 0 in S20
When CA=O is determined to be negative, the counter value of CCA is decremented by 1 in S21 (the counter value of CCA is decremented by 1).
Set to CA. Through the processing of this counter subtraction routine, the elapsed time since the stop phase 90A was held and excited is counted, and when 0CA=O, that is, 5°Q m5
When eC elapses, in step 83 of the main routine described above, the holding excitation that has been continued up to that point is turned off (time t5 in FIG. 6).

As explained above, the typewriter 1° of the embodiment has a CA
When starting a stepping motor, if the stopped phase of the rotor of the motor is held and excited, that is, if the rotor is stopped opposite the stopped phase due to holding excitation, the drive signal Immediately excite each excitation phase according to a predetermined procedure. On the other hand, if the stopped phase is not excited, the stopped phase is once pre-excited to force the rotor to face the stopped phase, and then each excitation phase is excited.

Therefore, when starting the rotor, the rotor starts rotating after the correspondence between the rotor and the stopped phase is reliably secured. Further, when performing continuous printing, pre-excitation is not performed every time the rotor is started, so the time required for the stopped rotor to start rotating can be shortened. That is,
The time it takes to print one character is 59m5ec (6msec)
49 m from cx4+25m5eC+10m5eC)
5ec (6m5ecx 4 + 25m5ec). Therefore, the time required for moving the carriage 70 of the typewriter 10 is shortened, and printing speed can be increased. In other words, in this embodiment, processing other than carriage movement during continuous printing is performed within a period of 25 n5ec (from time t1 to t3 in Figure 6) after the carriage starts moving and stops, so the carriage movement The printing speed is determined by the printing speed, and that speed is increasing. Furthermore, in this embodiment, the current is cut off after a predetermined time (500 m5ec) has elapsed since the CA stepping motor 90 has stopped, so it is possible to prevent the motor from generating heat and to save energy.

In this embodiment, the case where the stepping motor control device according to the present invention is applied to control the CA stepping motor of a typewriter has been described.
It goes without saying that the present invention can be applied to control not only a stepping motor for winding up a printing ribbon, but also various stepping motors used in various devices other than printing devices.

Effects of the Invention As described above in detail including the embodiments, the stepping motor control device of the present invention prevents uneven rotation, step-out, etc. when starting a stopped stepping motor, and reduces the time required for starting. This makes it possible to shorten the time required to achieve a smooth and quick start-up.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the structure of the present invention, FIG. 2 is a block diagram showing the structure of a typewriter according to an embodiment of the present invention, and FIG. 3 is a schematic structure of a stepping motor used in the typewriter. Figures 4 to 5(a) and 5
Figure (b) is a flowchart processed in the same embodiment, the sixth
The figure is an explanatory diagram for explaining the processing content based on the above flowchart. 10... Typewriter 90... Carriage stepping motor 110...
・Electronic control device agent Patent attorney Tsutomu Sadatsu (2 idiots) Figure 1 Figure 3 Figure 4 (a) (b)

Claims (1)

[Claims] 1. a movable element driving means for driving the movable element to a predetermined stop position by sequentially exciting a plurality of excitation phases in a predetermined order based on a drive signal; prior to driving the movable element by the movable element driving means; pre-excitation means for exciting the stop phase in which the movable element is stopped over a predetermined pre-excitation period; and after the movable element is stopped at the stop position by the movable element drive means, the movable element is moved to the stop position for a predetermined holding period. stop position holding means for exciting a stop phase of the movable element to hold the movable element at the stopped position; and when the drive signal is input within the holding period of the stop position holding means, the movable element driving means is immediately executed. and drive procedure setting means for causing the pre-excitation means to subsequently execute the movable element drive means when the drive signal is input after the elapse of the holding period.