JP2861091B2 - Motor control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a technique for judging an abnormality of a motor that repeats stop, start, and steady operation.

2. Description of the Related Art Conventionally, a control device for a motor that repeats stop, start, and steady operation by a motor driving unit, for example, a motor that is built in an electronic device and feeds an ink ribbon, tape, paper, or the like, is turned on by a computer. The motor is driven by open control without causing a field-back of the operating state of the motor, such as starting the motor by a signal and stopping the motor by an "off" signal from a computer.

Further, such a motor control device is provided with an overcurrent protection device such as a fuse or a breaker for protecting the motor and its driving means from an excessive current due to a short circuit of the motor winding or a motor lock.

[Problems to be Solved by the Invention] However, according to the conventional technology, it is possible to cut off an excessive current caused by a motor lock or the like so that damage to a motor or a motor driving unit is not expanded. It was not possible to detect an abnormality of each part related to the operation of the motor, such as occurrence, disconnection or short circuit of the motor winding, or failure of the motor driving means. For this reason, conventionally, there has been a problem that the function of an electronic device equipped with the motor is partially damaged or troublesome to find a place where the abnormality has occurred, since the operation of the motor is left undiscovered without any abnormality being detected. Was.

SUMMARY OF THE INVENTION It is an object of the present invention to determine the occurrence of an abnormality in each part related to the operation of a motor by solving the above problems.

[Means for Solving the Problems] As means for achieving the above object, a motor control device of the present invention repeats stop, start, and steady operation by motor drive means MA as illustrated in FIG. motor
In the control device of the MB, an energization state detecting means MC for detecting a value reflecting the energization current of the motor MB;
A time-measuring means MD for starting time measurement from the start of start-up of the motor MB, and an energizing current storage means ME for storing in advance a normal energizing current of the motor MB when the motor MB is stopped and a predetermined time has elapsed from the start. And comparing the value of the detected energizing current with the value of the stored energizing current when the motor MB is stopped and when the timing means MD has finished measuring the predetermined time, and Abnormality determination means MF that determines that an abnormality has occurred in any of the units involved in the operation of the MB
The gist is to provide

[Operation] The motor control device of the present invention is characterized in that the motor drive means MA stops the motor MB which repeats stop, start, and steady operation, and stops the motor MB. At the end of the lapse of time, the motor current is compared with a value reflecting the energizing current of the motor MB detected by the abnormality determining means MF by the energizing state detecting means MC and the energizing current stored in advance by the energizing current storage means ME. It is determined whether an abnormality has occurred in any of the units relating to the operation of the MB.

Accordingly, when a value reflecting the actually detected energizing current corresponds to the energizing current stored in advance, it is determined that no abnormality has occurred. On the other hand, when the value that reflects the actually detected energizing current does not correspond to the energizing current stored in advance, for example, when stopping, starting,
Alternatively, when the difference between the two values during the steady operation is equal to or more than a predetermined value, it is determined that there is an abnormality in any of the units related to the operation of the motor MB. In addition, based on the state of the stop, the start, or the steady operation, and the state of the deviation between the two values, the occurrence part or the content of the abnormality is specified.

[Embodiment] Next, an embodiment of a motor control device of the present invention will be described.

FIG. 2 is a configuration diagram showing a circuit configuration of the motor control device 1 of the present embodiment. FIG. 3 is a dot impact type printer 5 including the motor control device 1 for controlling the drive of the print ribbon feed motor 3. FIG.

As shown in FIG. 3, the printer 5 includes a platen 9 and
A carriage 13 on which the print head 11 is mounted, and a print head 11
And a printing ribbon 7 sent along the printing surface of the printer, and has a known configuration for printing on the paper 15 sent as the platen 9 moves. The print ribbon 7 is pulled out from the draw-out end 19 of the ribbon cartridge 17 by the ribbon feed operation of the print ribbon feed motor 3, passes through the ribbon guide 21 of the print head 11,
It is drawn into the drawing end 23 of 17.

The print ribbon feed motor 3 for sending the print ribbon 7 to the print head 11 is disposed near the retraction end 23 of the ribbon cartridge 17 as shown by a dotted line in FIG. 3, and as shown in FIG. After the rotation of the print ribbon feed motor 3 is reduced to a predetermined speed by the reduction gear 25, the capstan 27 is driven to rotate. The capstan 27 rotates while sandwiching the print ribbon 7 with a pinch roller (not shown), and draws the print ribbon 7 from the drawing end 23.

As the print ribbon feed motor 3 for feeding the print ribbon 7 according to the above-described configuration, a DC commutator motor whose conduction current increases during low-speed rotation such as startup is used. Not commutator through the second
The motor control device 1 shown in the figure is connected.

The motor control device 1 detects a power supply unit 31 that supplies DC power to the print ribbon feed motor 3 and a voltage value VT that reflects a current value of the power supplied to the print ribbon feed motor 3 by the power supply unit 31. A voltage detection unit 33,
The electronic control unit 35 controls the power supply unit 31 and reads the voltage value VT of the voltage detection unit 33.

The electronic control unit 35 includes a CP as a well-known arithmetic logic operation element.
A / D converter 47 for converting a voltage value VT, which is an analog value, into a digital value, and a signal from the CPU 37. And a display drive unit 46 for displaying predetermined information on the display 48. With this configuration, the electronic control unit 35
While controlling the power supply unit 31 via the output interface 43, the voltage value VT output from the voltage detection unit 33 is A / D
Input is performed via the converter 47 and the input interface 45.

The power supply unit 31 includes a DC power supply terminal Vcc1 (here, DC39
(V)) and the power system ground terminal PoV, a fuse 49, a power transistor 51, an armature winding 29 of the print ribbon feed motor 3, and a current detecting resistor 53 (here, 12 ( Ω)) in series in this order. The base of the power transistor 51 which switches the current flowing through this circuit is connected to the drive circuit 55.

The drive circuit 55 in the power supply unit 31 includes a latch that temporarily holds a state of a signal output from the output interface 43, and a power transistor based on the state of the latch.
A driver for outputting an “ON” signal or an “OFF” signal is provided at the base of the 51.

A protection diode 57 is connected in parallel to the print ribbon feed motor 3 to which power is supplied when the power transistor 51 is turned “ON”.
When the power transistor 51 is inverted to the “OFF” state or the like, the power transistor 51 and the like are protected by absorbing the reverse start generated from the print ribbon feed motor 3.

The voltage detection unit 33 includes a current detection resistor 53 and a conductor 59 that supplies an A / D converter 47 with a voltage value VT generated between the current detection resistor 53 and a power system ground terminal PoV due to the voltage drop. In addition, between the conductor 59 and the control voltage terminal Vcc2, a protection diode 61 for removing high-voltage noise entering the conductor 59 and protecting the A / D converter 47 is interposed. A capacitor 63 is interposed between the lead wire 59 and the control system ground terminal OV. The capacitor 63 temporarily increases the voltage level of the power system ground terminal PoV when the motor is turned on and off. And other noise signals,
Absorb the ground level difference that affects the voltage value VT.

Next, the present embodiment will be described based on a flowchart of an abnormality determination routine shown in FIG. 5 performed by the motor control device 1. The abnormality determination routine is a process repeatedly executed by the CPU 37 while power is supplied to the electronic control unit 35. When this abnormality determination routine is started,
First, it is determined whether or not a signal for turning on the print ribbon feed motor 3 is output to the drive circuit 55 via the output interface 43 of the electronic control unit 35. The determination is made based on whether or not the flag is set (Step 100, hereinafter, the step is simply referred to as S).

If it is determined that the print ribbon feed motor 3 is not "ON", the voltage value VT input through the A / D converter 47 and the input interface 45 is set to a predetermined value VA ( Here, it is determined whether or not the current is actually flowing through the print ribbon feed motor 3 by determining whether or not the current value is larger than 1 (V) (S110). If it is determined that the detected voltage value VT is equal to or less than the predetermined value VA,
It is determined that each unit is operating as instructed by the electronic control unit 35, and the process returns to the determination of the “ON” and “OFF” states of the print ribbon feed motor 3 (S100).

On the other hand, when it is determined that the voltage value VT is larger than the predetermined value VA, the electronic control unit 35 does not output a command to turn on the print ribbon feed motor 3, but the print ribbon feed motor 3 is not output. It is determined that there is an abnormal cause as shown below because the current is flowing through S3 (S12).
0). That is, the cause of the abnormality is the power transistor 5
It is determined that a short circuit of 1, a failure of the drive circuit 55, a failure of the electronic control unit 35, or an abnormal operation has occurred.

After the determination of the cause of the abnormality, the content of the determination is sent to the display drive unit 46 to be displayed on the display 48, and this routine ends. In this case, this routine is not restarted until the initialization process is performed by turning on the power again.

By the above processing of S100 to S130, after the power is turned on as shown in FIG. 6, before the time T0 at which the "ON" signal of the print ribbon feed motor 3 is output from the electronic control unit 35 to the drive circuit 55, It is determined whether or not the voltage value VT has become larger than the predetermined value VA, and based on the result, it is determined whether or not there is an abnormality in each of the related parts.

At time T0, the control of the print ribbon feed motor 3 is "OFF"
When the state changes from the “on” state to the “on” state, it is determined whether the print ribbon feed motor is “on” (S100).
It is determined that the “ON” state has been reached, and then a time counting process for a predetermined delay time (here, 20 (ms)) t1 (delay t1) is executed (S140). When the process of the delay t1 is completed and the time point T1 is reached, that is, the time point at which the starting current will reach the maximum value, the voltage value VT detected at this time point T1 and the predetermined value VB1 as shown in FIG. 2 (V)) and a predetermined value VB2 larger than the predetermined value VB1 (here, 2.3
(V)) is compared as shown below, and an abnormality determination of each unit when the print ribbon feed motor 3 is started is executed (S150).

That is, here, the voltage value VT is abnormally the predetermined value VB2, the voltage value VT is smaller than the predetermined value VB2 and the predetermined value VB1 is abnormal, or the voltage value VT is the predetermined value VB2.
It is determined whether it is less than one.

If the result of this determination is that the voltage value VT is smaller than the predetermined value VB1 as shown in (2), it is determined whether an appropriate current is flowing through the print ribbon feed motor 3 or the voltage value VT reflecting the current value. Are not detected, for example, disconnection of the fuse 43 due to short-circuit of the connector or internal wiring of the print ribbon feed motor 3 or short-circuit of the protection diode 57, failure of the power transistor 51 (disconnection or open), It is determined that an abnormality such as disconnection of the print ribbon feed motor 3 or connection at the end of the connector or short-circuit of the current detection resistor 53 has occurred (S160).

On the other hand, when it is determined that the voltage value VT is smaller than the predetermined value VB2 and is higher than the predetermined value VB1 by 3 as shown in (1), the starting current of the print ribbon feed motor 3 is flowing, Since it is smaller, it is determined that the load at the time of startup is small, that is, the case where the print ribbon 7 is not mounted (S170).

After the determination is made as described above or the abnormal content is specified, the abnormal content is displayed as described above (S130).

As a result of the determination of the voltage value VT at the time of starting, when the voltage value VT is determined to be equal to or more than the predetermined value VB2 as shown in FIG. In this way, the abnormality determination of each part during the steady rotation is executed.

First, a predetermined time t2 (for example, 500 (m) from time T0 as shown in FIG.
s) A process (delay t2) of timing until the time reaches (S180) is executed (S180).

Next, the voltage value VT detected at this time T2 is changed to the predetermined value VC.
By determining whether or not the voltage is greater than (1.5 (V) in this case), a voltage value at which an excessive current is flowing in the print ribbon feed motor 3 or a voltage value at which an excessive current is flowing is determined. It is determined whether or not VT has been detected (S190).

Here, when it is determined that the voltage value VT is larger than the predetermined value VC, it is determined that the content of the abnormality is a fixation of the print ribbon feed motor 3 or a defective ribbon feed, or a disconnection of the current detection resistor 53. (S200). Next, as described above, the content of the abnormality is displayed (S130).

On the other hand, if the voltage value VT is equal to or less than the predetermined value VC, that is, if no abnormality has occurred in all the components, the voltage value VT is maintained until the “OFF” command of the print ribbon feed motor 3 is output to the drive circuit 55. The comparison between VT and the predetermined value VC is repeatedly executed (S210).

Here, when a command to turn off the ribbon feed motor 3 is issued, after measuring a predetermined delay time t3 (delay t3) set for the following reason (S220), the process returns to the beginning of the abnormality determination routine. Then, the abnormality determination when the print ribbon feed motor 3 is "OFF" is performed again.

After the print ribbon feed motor 3 is turned off, it is turned off again
The delay t3 until the abnormality determination at the time (S110) is performed immediately after the print ribbon feed motor 3 is turned off, for example, even if the motor 3 and its drive circuit 55 are normal, the induction action of the armature winding 29 and The voltage value VT input to the A / D converter 47 is set so as to cope with the situation where the voltage value VT does not immediately become zero due to the wiring of each part of the motor control device 1 and the capacitance of the capacitor 63 and the like.

The motor control device 1 described above outputs a command to start the print ribbon feed motor 3 before output (before time T0),
Immediately after the start command is output (time T1) and in the case of the steady rotation state after the start (time T2), the voltage value VT reflecting the current supplied to the print ribbon feed motor 3 is set to a predetermined value. Based on the comparison result, the contents of the abnormality of each part relating to the operation of the print ribbon feed motor 3 are determined and displayed.

As a result, the operation of the print ribbon feed motor 3 does not continue for a long time without being detected, so that there is an extremely excellent effect that the print quality is not deteriorated. In addition, since the content of the operation abnormality is roughly specified, an excellent effect that the repair becomes easy and the time required for the repair is shortened is exerted.

Note that the present invention is not limited to the above embodiment,
As described below, the present invention can be applied to a device for determining various motor abnormalities without changing the gist of the present invention.

In addition to determining and displaying an error as in the present embodiment, based on the details of the determined error, if the printing is not possible, the printer operation can be stopped or printing can be performed. If there is any abnormality, a configuration for performing control such as printing as it is may be added.

A failure in which the power transistor 51 is always in the “ON” state and the print ribbon feed motor 3 constantly rotates does not directly reduce the print quality. Therefore, the voltage value VT for determining this abnormality and a predetermined value are determined. The comparison with VA (S110) may be omitted to simplify the abnormality determination routine. or,
Similarly, when the print ribbon 7 is not attached, since it is easy to find because no print is performed,
The voltage value VT for determining this abnormality is a predetermined value VB.
The determination of whether or not it is between 1 and VB2 (flow from S150 to S170) may be omitted.

As described above, the comparison between the voltage value VT and the predetermined value VA (S1
10) If both the determination of whether the voltage value VT is between the predetermined values VB1 and VB2 (the flow from S150 to S170) is omitted, the predetermined value for comparison with the voltage value VT V
(E.g., V = 1.5 (V)), (i)
When the print ribbon feed motor 3 is started, it is determined that there is an abnormality when the voltage value VT is smaller than the predetermined value V (VT <V). (Ii) When the voltage value VT is larger than the predetermined value V during steady rotation ( (VT> V), it can be determined that there is an abnormality, which can be further simplified.

When printing by the print head 11 is performed in both directions, that is, in both the forward direction (FWD direction) and the reverse direction (REV direction), the print ribbon 7 is fed in a fixed direction. Therefore, the load of the print ribbon feed motor 3 changes between the FWD direction and the REV direction, and as a result, the detected voltage value VT differs between the FWD direction and the REV direction.
Therefore, paying attention to this difference in the printing direction, the printing direction is provided with the predetermined values VB1, VB2 and Vc for the FWD direction and the predetermined values VB1, VB2, VC for the REV direction separately, and the accuracy of abnormality determination is improved. The configuration may be improved. Further, even when the feeding of the print ribbon 7 is stopped, the next few lines (at least 1
Line), the print quality does not deteriorate, so the FWD
The configuration may be such that the abnormality is determined only in one of the direction and the REV direction.

A predetermined value VC for judging abnormality of each part when the print ribbon feed motor 3 is rotating at a steady state is set to a predetermined value VC.
Is set to a value which is slightly larger than the voltage value VT in the case where the motor is operated properly, and the operation of the print ribbon feed motor 3 is performed when the number or frequency of the voltage value VT becomes larger than the predetermined value VC or the number of continuous times becomes large. May be determined to be abnormal. As a result, the sensitivity for detecting an abnormality can be increased, and the voltage value VT is temporarily changed by the fluctuation of the voltage value VT caused by the load fluctuation due to the printing state.
Will not be erroneously determined even if is larger than the predetermined value VC.

In the embodiment, the function of judging abnormality is provided by a power transistor.
Although it is configured to be integrated with the electronic control unit 35 that controls the drive of the 51, an A / D converter, a ROM, and the like are built in instead.
The chip type microcomputer may be configured to determine only the abnormality of each part related to the operation of the motor. In this way, by using a dedicated microcomputer, other than this microcomputer, it is possible to detect an abnormality of each part only by interposing a current detection resistor in series with the motor, so that the versatility is high. In addition, it is possible to provide an abnormality detection device having a small number of parts.

[Effects of the Invention] The motor control device according to the present invention obtains a model in which the motor is properly operated when the motor is stopped and when the motor is operating, and detects a previously stored energizing current and an actually detected current. Based on the deviation from the value reflecting the energizing current, it is determined that an abnormality has occurred in any of the units related to the operation of the motor. As a result, it is determined that the state of the motor is not appropriate by detecting a value reflecting the current supplied, and therefore, an abnormality occurs in each part related to the operation of the motor without actually detecting the operation state of the motor. Can be determined.

As a result, since there is no case where the abnormality of each part relating to the operation of the motor is not detected and left undetected, there is an extremely excellent effect that the reliability of the device driven by the motor is improved. In addition, compared to a case where the operation of the motor is actually monitored by the encoder and the state where the motor is not operating is detected, an excellent effect that the number of components can be reduced can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a basic configuration of a motor control device according to the present invention, FIG. 2 is a wiring diagram illustrating a configuration of an electric circuit of the motor control device according to the embodiment, and FIG. FIG. 4 is a block diagram showing the periphery of the print ribbon feed motor, FIG. 5 is a flowchart of the abnormality determination routine, and FIG. 6 is an explanatory diagram of the operation. MA: motor driving means MB: motor MC: energizing state detecting means MD: clocking means ME: energizing current storage means MF: abnormality judging means 1: motor control device 3: print ribbon feed motor 5 … Printer 7… Printing ribbon 31… Power supply unit 33… Voltage detection unit 35… Electronic control unit

Claims (1)

(57) [Claims] 1. A motor control device which repeats stop, start and steady operation by a motor drive means, comprising: an energization state detection means for detecting a value reflecting an energization current of the motor; Time-measuring means for starting; current-current storage means for storing in advance a normal current-flow of the motor when the motor is stopped and when a predetermined time has elapsed from the start; and when the motor is stopped and the time-measuring means A value reflecting the detected energizing current when the clocking of the predetermined time is completed,
A motor control device comprising: an abnormality determination unit configured to determine whether an abnormality has occurred in any of the units related to the operation of the motor by comparing the stored current value with the current value.