JPH06296381A - Drive control device - Google Patents

Abstract

PURPOSE:To make it possible to prevent a failure in starting and occurrence of an unstable speed control even when a load torque changes sharply, by a method wherein an actuating level is increased gradually at the time of starting of a motor and, when a drive is detected, switchover is made to a control of adjusting the actuating level by a feedback control. CONSTITUTION:A program timer 150 and a motor driver 200 are controlled by a microcomputer and a PWM control of an electric motor M7 is executed. At the time when a starting processing is commenced, a generated torque of the electric motor M7 is smaller than a load torque and the motor M7 is not started. As the time width of electrification is made long with the passage of time, the generated torque of the motor M7 exceeds the load torque and the motor M7 is started then. When the motor M7 is started, a pulse is generated from a rotary encoder ENC, the starting processing is ended when the pulse is detected, and switchover is made to an ordinary speed control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor start-up control device and can be used for controlling an electric motor for driving a scanner of a copying machine.

[0002]

2. Description of the Related Art For example, in the case of a DC electric motor for driving a scanner of a copying machine, the voltage applied to the electric motor is adjusted by PWM (pulse width modulation) control, and thereby the drive torque is controlled. In the case of starting an electric motor in this type of control, conventionally, a predetermined starting voltage is applied to the electric motor.

However, it is very difficult to set the starting voltage. That is, the load torque of the motor is
It changes according to changes over time, changes in temperature and humidity, and the starting torque can also change due to changes in the power supply voltage. When the voltage applied to the electric motor at the time of starting is relatively small and the starting torque is small, the starting of the motor may fail.
Conversely, if the motor applied voltage at start-up is large and the start-up torque is far larger than the load torque, the start-up speed is too fast, speed control will not be in time, and an overshoot etc. will occur. The control operation may become unstable. Even if the starting voltage is set to the optimum value by design, the starting failure or unstable speed control may occur depending on variations in mechanical characteristics between devices and conditions at that time. Therefore, it is necessary to reduce variations in driving torque and load torque, and high precision is required for the parts used. In addition, adjustment may be required for each device.

[0004]

SUMMARY OF THE INVENTION According to the present invention, in a start control device for a motor, even if the load torque of the motor can change significantly, it is possible to prevent the start failure or the occurrence of unstable speed control. The purpose is to do.

[0005]

In order to achieve the above object, in the present invention, the energizing level (for example, applied voltage) of the electric motor is controlled until the electric motor is started.
It gradually increases with time.

[0006]

By doing so, it is possible to prevent the start-up failure and the occurrence of unstable speed control. That is, when the load torque is small, the drive torque becomes larger than the load torque at a relatively early time after the start of the start-up, the motor starts up, and the start-up control ends at that point. It does not become much larger, and the start-up speed does not rise sharply. Further, when the load torque is large, the drive torque increases with time. Therefore, the drive torque becomes larger than the load torque and the motor starts at a relatively late time after the start of the start. In other words, although the motor starts up a little later, the motor does not fail to start up.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 3 and 4 show the structure of a mechanical section of an optical scanning system of one type for carrying out the present invention. This will be described with reference to FIGS. 3 and 4. The original placed on the contact glass 1 is exposed by the exposure lamp 2a located below the original. The reflected light from the document is the first mirror 2c, the second mirror 2d, the third mirror 2e, the lens 2f, and the fourth mirror 2g.
And, it is guided to the photoconductor drum 3 through the dustproof glass 2h.

The exposure lamp 2a and the first mirror 2c are the first
It is mounted on the carriage 51, and the second mirror 2d and the third mirror 2e are mounted on the second carriage 52. In order to scan the document, the first carriage 51 and the second carriage 51
The carriage 52 is reciprocally driven and scanned in the left-right direction in FIG. The first carriage 51 and the second carriage 52 are arranged so that the optical path length from the document to the photosensitive drum does not change.
And are driven at a speed ratio of 2: 1.

This optical scanning system is driven by a DC electric motor M7 shown in FIG. A home position sensor HP1 and a return position sensor RP1 are provided to detect the home position and the return position in the scanning range, respectively.

An electric circuit for controlling the driving of the optical scanning system shown in FIGS. 3 and 4 is shown separately in FIGS. With reference to FIGS. 1 and 2, the main components include a microcomputer 100, a programmable timer 150, a motor driver 200, an oscillator 310, and a flip-flop 320.

Microcomputer 1 used here
00 is μPD7811G manufactured by NEC Corporation. The programmable timer 150 is 8253. It has three independent timers inside and clock input terminal C
LKn, gate control terminal GATEn and output terminal OUT
Although n (n = 0, 1, 2) are provided, in this example two timers are used to generate the signal. A clock pulse signal having a constant period is applied from the oscillator 310 to the two timers.

The motor driver 200 is provided with four switching transistors Tr ₁ , Tr ₂ , Tr ₃ and Tr ₄ and is capable of supplying current to the electric motor M7 in both forward and reverse directions. The programmable timer 150 and the motor driver 200 are controlled by the microcomputer 100.

A rotary encoder ENC is connected to the drive shaft of the electric motor M7. This rotary encoder ENC has two-phase electric pulse signals ENCA and ENCB each time the drive shaft of the electric motor M7 moves a minute amount.
Is output as a feedback signal. These feedback signals are input to the input port C1 and PC7 of the microcomputer 100.

Next, the control of the electric motor M7 will be specifically described. In the motor driver 200, when the transistors Tr ₁ and Tr ₃ are turned on, the electric motor M7
A current flows in the forward direction and rotates clockwise. On the contrary, when the transistors Tr ₂ and Tr ₄ are turned on, the electric motor M
An electric current flows in the opposite direction to 7 and rotates counterclockwise. The microcomputer 100 has output ports PF6 and PF.
7 controls the transistors Tr ₁ and Tr ₂ and thereby determines the direction of rotation of the electric motor M7.

The on / off of the actual energization of the electric motor M7 is controlled by the electric signals output from the gate circuits G5 and G6. This electric signal is generated by the programmable timer 150. An outline of the operation of the timer 150 is shown in FIG. As will be described later, the timer 150
The 0th set of counters inside the
The counters in the set are set to mode 1. The operation of each mode in the timer 150 is as follows.

Mode 1: The output goes low (low level) on the count following the rising edge of the gate input and goes high (high level) after the terminal count.

Mode 3: It operates as an n frequency divider corresponding to the set value, and a repetitive pulse signal obtained by dividing the clock pulse appears at the output terminal. H and L duty is 50%
Is.

Therefore, depending on the value set in the 0th counter of the timer 150, the repetition period Ton shown in FIG.
+ Toff is determined, and the on-time (energization time) Ton is determined by the value set in the first set of counters. By the signal obtained at the output terminal OUT1 of the timer 150,
The transistors Tr ₃ and Tr ₄ are turned on / off, and the electric motor M7 is energized. That is, the electric motor M7 is intermittently energized, and so-called PWM control is performed. Timer 15
By updating the value set in the first set of counters of 0, the energizing pulse width Ton changes and the drive torque generated by the electric motor M7 changes.

FIG. 6 shows an outline of the speed change of the electric motor M7. In this example, when the electric motor M7 is driven clockwise, the optical scanning system moves forward, and when the electric motor M7 is driven counterclockwise, the optical scanning system moves backward. The speed is higher in the backward movement than in the forward movement, and the time required for movement is shorter.

The microcomputer 1 shown in FIGS. 1 and 2.
FIG. 7 shows an outline of the motor starting operation of No. 00. The operation of the microcomputer 100 will be described with reference to FIG.
First, the 0th set of counters of the timer 150 is set to mode 3, and a predetermined value CNTCO is set as its count value. Thus, the 0th set of counters of the timer 150 outputs a square wave whose period is determined by the value of CNTCO and the period of the clock pulse. This square wave
0 to the gate terminal GATE1 of the first set of counters.

Next, the first set of counters of the timer 150 is set to mode 1, and CNT1ST is set as its count value. As a result, the first set of counters has gate terminals (GA
Immediately after the signal of TE1) becomes H, L is synchronized with the falling edge of the clock signal for the time Ton corresponding to CNT1ST.
become. Since the initial value of CNT1ST is set to a relatively small value, the initial value of Ton is relatively small.

Next, the output port PF6 is set to L.
That is, the driving direction of the electric motor M7 is set clockwise. The electric motor M7 is now ready for activation. Although not shown, an internal timer used for detecting abnormality is started here. Then, the presence or absence of the signal ENCA from the rotary encoder ENC is checked by the input port C1. If there is no signal, ie electric motor M
If 7 is not activated, the minute value Δ is added to the energization time data CNT1ST, thereby updating the set value of the first set of counters. And again, check for the signal ENCA,
This operation is repeated until the signal ENCA is detected.
However, the count value of the internal timer is the maximum value Tmax set in advance.
When it becomes larger, it is considered that an abnormality has occurred and the predetermined abnormality processing is performed. When the signal ENCA is detected, the starting process is ended and the process proceeds to the speed control process.

That is, in this example, since the value CNT1ST that determines the energization time Ton gradually increases after the start-up process is started, the drive torque of the electric motor M7 increases with time.

Driving torque Tm generated by the electric motor M7
Is Kt: motor torque constant Vmm: motor applied voltage R: motor armature resistance Tpwm: PWM control cycle Ton: PWM on time N: motor speed Ke: motor induced voltage coefficient It is represented by.

Tm = Kt (Vmm−Ke · N) Ton / (R · Tpwm) (1) Considering the case of starting, the motor rotation speed is 0. Therefore, the generated torque Tms is It is expressed by equation (2).

Tms = (Kt · Vmm / R) · (Ton / Tpwm) (2) That is, the generated torque Tms increases as the duty of the PWM control energization time increases.

FIG. 8 shows the operation of the apparatus shown in FIGS. 1 and 2 when the load torque is relatively small. The load torque is relatively small, but when the start process is started, that is, the electric motor M
When the energization of No. 7 is started, the motor generated torque is smaller than the load torque, so the motor does not start. However, since the energization time Ton becomes longer as time passes,
The torque generated by the motor increases in proportion to time, and the torque generated by the motor exceeds the load torque within a relatively short time, and the motor starts at that time. When the motor is activated, a pulse (ENCA) is output from the rotary encoder, so that when it is detected, the activation process ends and the normal speed control is started.

FIG. 9 shows an operation example in the case of performing the conventional control, that is, in the case of keeping the energizing level of the motor constant. The load torque is the same as in the case of FIG. Referring to FIG. 9, it can be seen that the motor is normally started. However, in FIG. 8, it can be seen that the rotation speed of the motor rises smoothly, whereas in FIG. 9, an overshoot occurs in the change of the rotation speed of the motor. That is, FIG. 1 and FIG.
In this device, the rotation speed does not rise sharply and the operation is stable.

FIG. 10 shows the operation of the apparatus shown in FIGS. 1 and 2 when the load torque is relatively large. When the starting process is started, that is, when the energization of the electric motor M7 is started, the motor generated torque is smaller than the load torque as in the case where the load torque is small, and therefore the motor is not started.
However, since the energization time Ton becomes longer with the passage of time, the motor-generated torque increases in proportion to the time, and after a lapse of a predetermined time, the motor-generated torque exceeds the load torque and the motor is started at that time. When the motor starts,
Since a pulse (ENCA) is output from the rotary encoder, when it is detected, the start-up process ends and the normal speed control is started.

FIG. 11 shows an operation example in the case of performing the conventional control, that is, in the case of keeping the energizing level of the motor constant.
The load torque is the same as in the case of FIG. Referring to FIG. 11, it can be seen that the load torque is larger than the drive torque preset as the motor starting torque, so that the motor does not start at any time.

Referring to FIGS. 8 and 10, in the devices shown in FIGS. 1 and 2, the time required from the start of energization to the actual start of the motor varies somewhat depending on the magnitude of the load torque. Even if there is a large change, the motor is surely started, and the starting characteristics do not become unstable.

The speed control after the motor is started is the same as the conventional control. That is, the microcomputer 100
Measures the period of the feedback signal applied to the input port C1 to detect the rotation speed of the motor, and a voltage corresponding to the difference between the detected rotation speed and a preset target speed is applied to the motor M7. As described above, the energization time Ton is updated. The signal applied to the input port PC7 indicates the rotation direction of the electric motor M7.

In the above embodiment, the signal from the rotary encoder is monitored to detect whether or not the electric motor is started. However, if the presence or absence of the electric motor can be detected, another detection is performed. The signal from the means may be monitored.

[0035]

As described above, according to the present invention, even when the load torque or the power supply voltage fluctuates or the characteristics of the individual motors have a relatively large variation, a start-up failure occurs or the operation is not performed. There is no instability and no adjustment is required.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control circuit of an electric motor M7.

FIG. 2 is a block diagram showing a configuration of a control circuit of an electric motor M7.

FIG. 3 is a front view showing a configuration of a mechanical section of an optical scanning system of a copying machine.

FIG. 4 is a perspective view showing a configuration of a mechanical section of an optical scanning system of a copying machine.

5 is a timing chart showing the operation of the timer 150 shown in FIGS. 1 and 2. FIG.

FIG. 6 is a timing chart showing a change in speed of the apparatus shown in FIGS.

FIG. 7 is a flowchart showing a motor starting process of the microcomputer 100 of FIGS.

FIG. 8 is a timing chart showing a starting characteristic of the electric motor in the apparatus of FIGS. 1 and 2.

FIG. 9 is a timing chart showing a starting characteristic of an electric motor in an apparatus having a constant starting torque.

10 is a timing chart showing a starting characteristic of the electric motor in the apparatus of FIGS. 1 and 2. FIG.

FIG. 11 is a timing chart showing a starting characteristic of an electric motor in an apparatus having a constant starting torque.

[Explanation of symbols]

1: Contact Glass 2: Optical Scanning System 3: Photosensitive Drum 51: First Carriage 52: Second Carriage 100: Microcomputer (Electronic Control Means) 150: Programmable Timer 200: Motor Driver (Biasing Means) 310: Oscillator 320 : Flip-flop M7: DC electric motor (electric motor) ENC: Rotary encoder (motion detecting means) HP1: Home position sensor RP1: Return position sensor G1, G2: Gate circuit

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 13, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Drive control device

[Claims]

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 example, drive control of an electric motor that moves a scanner of a copying machine.
You can use it .

[0002]

2. Description of the Related Art For example, a direct current for moving a scanner of a copying machine.
In the case of an electric motor, PWM (pulse width modulation) control
Adjust the voltage applied to the electric motor, which
Drive torque is controlled. For this kind of control
When starting the electric motor with a
The starting voltage is applied to the electric motor.
It

However, it is very difficult to set the starting voltage.
Yes. That is, the load torque of the motor is
It changes according to changes with time, temperature and humidity, etc.
The driving torque of the power source can also be changed by the fluctuation of the power supply voltage. Beginning
The voltage applied to the electric motor during operation is relatively small
If the torque is small, the motor may fail to start.
There is. On the contrary, the motor applied voltage at the start is large,
If the drive torque is much larger than the load torque,
The speed at the time of starting was too fast, and the speed control was not in time.
The motor control operation becomes unstable due to the occurrence of bar chute etc.
Sometimes. By design, the starting voltage was set to the optimum value.
As a result, variations in mechanical characteristics between devices and
Depending on the situation, startup failure or unstable speed control may occur.
It is possible. Therefore, drive torque and load torque
It is necessary to reduce the variation and it is expensive for the parts used.
Precision is required. Also, adjustments may be required for each device.
There is also. As a result, the choice of motor is also
It was difficult.

In this document, whether the moving body is stationary
The fact that the robot actually starts moving is defined as "start"
The motor or load speed has been
Accelerating motion to reach the target speed is defined as "start"
It

[0005]

SUMMARY OF THE INVENTION The present invention is a drive control device.
If the load torque of the motor can change significantly during
Even if it is a failure, start failure or unstable speed control
The purpose is to prevent
The purpose is to simplify machine selection.

[0006]

Was to achieve the above object, there is provided a means for solving]
Therefore, in the present invention, until the electric motor is started
During which the energizing level (eg applied voltage) of the electric motor is
It gradually increases with time.

[0007]

[Operation] If this is done, startup failure or unstable speed
The occurrence of frequency control can be prevented. That is, the load torque is small
In some cases, the drive
Luku becomes larger than the load torque, the motor starts,
At that point, the start control ends, so the drive torque is
It does not become much larger than the torque, and the drive speed
No sharp rise occurs. When the load torque is large
, The driving torque increases with time,
Drive torque is loaded at a relatively late time after the start control is started.
When it becomes larger than the torque, the motor starts. That is,
It takes a while for the motor to start, but
You won't lose.

Other objects and features of the present invention are as follows.
It will be apparent from the description of the embodiments with reference to the surface.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG . 3 and FIG. 4 show one form of implementing the present invention.
The structure of the mechanical part of an optical scanning system is shown. Please refer to FIG. 3 and FIG.
And explain. Document placed on contact glass 1
Is exposed by the exposure lamp 2a located below it.
Be done. The reflected light from the document is reflected by the first mirror 2c and the second mirror.
-2d, third mirror 2e, lens 2f, fourth mirror 2g
And through the dustproof glass 2h to the photoconductor drum 3
Be done.

The exposure lamp 2a and the first mirror 2c are the first
It is mounted on the carriage 51 and has a second mirror 2d and
The third mirror 2e is mounted on the second carriage 52.
It In order to scan the document, the first carriage 51 and the second carriage 51
The carriage 52 is reciprocally driven and scanned in the left-right direction in FIG.
It Note that the optical path length from the document to the photosensitive drum has changed.
The first carriage 51 and the second carriage 52
And move at a speed ratio of 2: 1.

This optical scanning system is a DC electric motor shown in FIG.
Driven by the motor M7. Home position within scan range
To detect the home position and return position respectively.
Sensor HP1 and return position sensor RP1
It

The movement of the optical scanning system shown in FIGS.
The electric circuit to be controlled is shown separately in FIGS. Figure 1 and
2 and FIG. 2, the main components are micro
Computer 100, programmable timer 150, model
Data driver 200, oscillator 310, and flip-flop
Equipped with a 320.

Microcomputer 1 used here
00 is μPD7811G manufactured by NEC Corporation. The
The programmable timer 150 is 8253. This is
The clock input terminal C has three independent sets of timers
LKn, gate control terminal GATEn and output terminal OUT
n (n = 0, 1, 2), but two in this example
Timer is used to generate the signal. Two
The timer has a fixed frequency clock pulse from the oscillator 310.
Signal is applied.

The motor driver 200 has four switches.
With transistors Tr ₁ , Tr ₂ , Tr ₃ and Tr ₄
The electric motor M7 with a current flowing in both directions.
You can Programmable timer 150 and
The driver 200 is based on the microcomputer 100.
Is controlled.

A rotary shaft is provided on the drive shaft of the electric motor M7.
The encoder ENC is connected. This rotary
In the encoder ENC, the drive shaft of the electric motor M7 is slightly moved.
Every two phase electrical pulse signals ENCA and ENCB
Is output as a feedback signal. These fi
The feedback signal is input to the microcomputer 100.
Input to port C1 and PC7.

Next, the control of the electric motor M7 will be described in detail.
To explain. In the motor driver 200,
When the transistors Tr ₁ and Tr ₃ turn on, the electric motor M7
A current flows in the forward direction and rotates clockwise. On the contrary,
When the transistors Tr ₂ and Tr ₄ are turned on, the electric motor M
An electric current flows in the opposite direction to 7 and rotates counterclockwise. My
The black computer 100 has output ports PF6 and PF.
The transistors Tr ₁ and Tr ₂ are controlled via
This determines the rotation direction of the electric motor M7.

Turning on / off the actual energization of the electric motor M7
Is the electrical signal output from the gate circuits G5 and G6.
Therefore, it is controlled. This electrical signal is programmable
Generated by the imager 150. The operation of this timer 150
The outline of the work is shown in FIG. As will be described later, the timer 150
The 0th set of counters inside the
The counters in the set are set to mode 1. On timer 150
The operation of each mode is as follows.

Mode 1: The output is the rising edge of the gate input.
It becomes L (low level) in the count following J, and the terminal
It goes to H (high level) after counting.

Mode 3: As n frequency divider corresponding to the set value
It operates as a clock pulse and divides the clock pulse
Signal appears on the output terminal. H and L duty is 50%
Is.

Therefore, the 0th set of counters of the timer 150
Depending on the value set in, the repetition period Ton shown in FIG.
+ Toff is determined and the value to be set in the first set of counters
ON time (energization time) Ton is determined by. Thailand
According to the signal obtained at the output terminal OUT1 of the controller 150,
Transistors Tr ₃ and Tr ₄ are turned on / off and the electric motor
Energize M7. That is, the electric motor M7 is intermittently
It is energized and so-called PWM control is performed. Timer 15
To update the value set to the first set of counters of 0
Therefore, the energizing pulse width Ton changes and the electric motor M7
The generated drive torque changes.

FIG. 6 shows an outline of the speed change of the electric motor M7.
Show. In this example, the electric motor M7 is driven clockwise.
The optical scanning system moves in the forward direction and drives M7 counterclockwise.
The optical scanning system is moved back when the temperature rises. When returning, than when moving forward
However, the speed is high and the time required to move is short.

The microcomputer 1 shown in FIGS. 1 and 2.
FIG. 7 shows an outline of the motor starting operation of No. 00. See Figure 7
The operation of the microcomputer 100 will be described below.
First, the 0th set of counters of the timer 150 is set to the mode.
3 and set the predetermined value CNTCO as the count value.
To put. This completes the 0th set of counters of timer 150.
Is the cycle of the CNTCO value and the clock pulse cycle.
Outputs a square wave that determines. This square wave
0 to the gate terminal GATE1 of the first set of counters.
Be done.

Next, the first set of counters of the timer 150
Set to mode 1 and set CNT1ST as the count value
It As a result, the first set of counters has gate terminals (GA
The rising edge of the clock signal immediately after the TE1) signal goes high.
In synchronization with the falling, L for the time Ton corresponding to CNT1ST
become. The initial value of CNT1ST is set to a relatively small value.
Therefore, the initial value of Ton is relatively small.

Next, the output port PF6 is set to L.
That is, the driving direction of the electric motor M7 is set clockwise.
To do. Now the electric motor M7 can be started.
It Although not shown, it is used here to detect an abnormality.
Start the internal timer. Next, Rotary Enco
Whether the signal ENCA from the encoder ENC is present or not is determined by the input port C1.
I will check. If there is no signal, ie electric motor M
If 7 is not activated, the energization time data CNT1ST is a minute value
Δ is added, whereby the set value of the first set of counters is obtained.
Update. And again, check for the signal ENCA,
This operation is repeated until the signal ENCA is detected.
However, the count value of the internal timer is the maximum value Tmax set in advance.
If it becomes larger, it is considered that an abnormality has occurred and the prescribed
Go to abnormal processing. When the signal ENCA is detected, the startup process
The process ends, and the process proceeds to the speed control process.

That is, in this example, the starting process is started.
After that, the value CNT1ST that determines the energization time Ton
As it increases gradually, the drive torque of the electric motor M7 increases.
Luk grows over time.

Driving torque Tm generated by the electric motor M7
Is, Kt: motor torque constant Vmm: voltage applied to the motor R: motor armature resistance Tpwm: PWM control period Ton: PWM on-time N: Motor rotation speed Ke: if motor induced voltage coefficient, the following equation (1) It is represented by.

[0027] Tm = Kt (Vmm-KeN) Ton / (RTpwm) (1) Considering the case of startup, is the motor speed 0?
The generated torque Tms is expressed by the following equation (2).

[0028] Tms = (Kt · Vmm / R) · (Ton / Tpwm) (2) That is, the duty of the energization time of the PWM control is increased.
As it increases, the generated torque Tms increases.

FIG . 8 shows the case where the load torque is relatively small.
The operation of the apparatus shown in FIGS. Load torque comparison
Small, but when the start-up process is started, that is, the electric motor M
When energization of 7 is started, the torque generated by the motor is negative.
Since it is less than the load torque, the motor will not start. Only
However, since the energization time Ton becomes longer as time passes,
Motor generated torque increases in proportion to time and is relatively short
Within the time, the motor generated torque exceeds the load torque,
Sometimes the motor starts. When the motor starts, the rotary
-A pulse (ENCA) is output from the encoder
Then, when it is detected, the startup process ends and
Degree control.

FIG . 9 shows a case where conventional control is performed, that is,
An operation example when the bias level of the data is constant will be described. negative
The load torque is the same as in the case of FIG. Refer to FIG.
It turns out that the motor has started normally. However
However, in FIG. 8, the rotation speed of the motor is smoothly increasing.
On the other hand, in Fig. 9, the change in the motor speed is exceeded.
You can see that a shoot is occurring. That is, FIG. 1 and FIG.
With the device, the rotation speed does not rise sharply
Is stable.

FIG . 10 shows that the load torque is relatively large.
The operation of the apparatus shown in FIGS. Start the boot process
When the electric motor M7 is turned on,
As in the case where the load torque is small, the torque generated by the motor
Is less than the load torque, the motor will not start.
However, the energization time Ton becomes longer as time passes.
, The torque generated by the motor increases in proportion to time,
As time passes, the torque generated by the motor exceeds the load torque.
Well, at that time the motor starts. When the motor starts,
A pulse (ENCA) is output from the rotary encoder.
The startup process ends when it is detected, and
Move to normal speed control.

FIG . 11 shows a case where conventional control is performed, that is,
An example of the operation when the energizing level of the motor is made constant will be shown.
The load torque is the same as in the case of FIG. See Figure 11
Then, the drive torque preset as the starting torque of the motor is
Since the load torque is larger than Luk,
It can be seen that the motor does not start.

Referring to FIGS. 8 and 10, FIGS.
In the device shown, the motor is actually started from the start of energization.
The time required for changes slightly depending on the magnitude of the load torque.
However, even if the load torque changes greatly,
The motor will start and the starting characteristics will not become unstable.
Therefore, it turns out that it is very excellent.

The speed control after the motor is started is the same as the conventional speed control.
Similar to control. That is, the microcomputer 100
Is a feedback signal applied to the input port C1.
Measures the period and thereby detects the motor rotation speed
The difference between the detected rotation speed and the preset target speed.
Energizing time so that the corresponding voltage is applied to the motor M7
Update Ton. It is applied to the input port PC7
The signal indicates the direction of rotation of the electric motor M7.

In the above embodiment, the motor is started.
From the rotary encoder to detect the presence or absence of motion.
I am monitoring the signal but I want to detect if the motor is rotating
If the signal from other detection means is monitored,
Good.

[0036]

As described above, according to the present invention, the load
Fluctuations in the power supply voltage and the characteristics of individual motors.
Even if the wobble is relatively large, a start-up failure occurs
And the operation does not become unstable, and
No need for adjustment. Also, as a result of these
You don't have to think about choosing an electric motor
The selection of machine can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control circuit of an electric motor M7.

FIG. 2 is a block diagram showing a configuration of a control circuit of an electric motor M7.

FIG. 3 is a front view showing a configuration of a mechanical section of an optical scanning system of a copying machine.

FIG. 4 is a perspective view showing a configuration of a mechanical section of an optical scanning system of a copying machine.

5 is a timing chart showing the operation of the timer 150 shown in FIGS. 1 and 2. FIG.

FIG. 6 is a timing chart showing a change in speed of the apparatus shown in FIGS.

FIG. 7 is a flowchart showing a motor starting process of the microcomputer 100 of FIGS.

FIG. 8 is a timing chart showing a starting characteristic of the electric motor in the apparatus of FIGS. 1 and 2.

FIG. 9 is a timing chart showing a starting characteristic of an electric motor in an apparatus having a constant starting torque.

10 is a timing chart showing a starting characteristic of the electric motor in the apparatus of FIGS. 1 and 2. FIG.

FIG. 11 is a timing chart showing a starting characteristic of an electric motor in an apparatus having a constant starting torque.

[Description of Reference Signs] 1: Contact glass 2: Optical scanning system 3: Photosensitive drum 51: First carriage 52: Second carriage 100: Microcomputer (electronic control means) 150: Programmable timer 200: Motor driver (biasing means) ) 310: Oscillator 320: Flip-flop M7: DC electric motor (electric motor) ENC: Rotary encoder (motion detecting means) HP1: Home position sensor RP1: Return position sensor G1, G2: Gate circuit

Claims (1)

[Claims] 1. A start-up control device for an electric motor that drives a moving body according to an urging level, the operation detecting means detecting whether or not the electric motor is driven, and the operation detecting means for driving when the electric motor is started. Until the detection, the urging level is gradually increased, and when the operation detecting means detects driving, the urging is performed by feedback control according to a preset target value and the detected driving amount. An electric motor starting control device comprising: an electronic control unit for adjusting a level.