JP2003262904A - Motor driving controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor driving controller which avoids an increase in driving time during speed reduction control when a movable unit moved by a motor is brought under driving control. <P>SOLUTION: As an embodiment of the present invention, the motor driving controller is provided with the movable unit which can be moved by the motor, a pulse generating means, a speed detecting means, a position detecting means, a setting means, a motor driving mode selecting means, a braking frequency counting means, and a motor driving voltage determining means, and is characterized in that, when a motor-on mode is selected by the motor driving mode detecting means, the motor driving voltage determining means applies a 1st voltage to the motor if the braking frequency counted by the braking frequency counting means is less than a specified frequency and applies a 2nd voltage lower than the 1st voltage to the motor when the braking frequency is large than a specific frequency. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION [0001] The present invention relates to a motor drive control device.
Movable unit, especially movable by motor
For example, lens drive of zoom camera, fill
Used for drive control of the zoom drive unit, etc.
The present invention relates to a motor drive control device. 2. Description of the Related Art Conventionally, a movable unit
As a motor drive control device for controlling the drive of
In JP-A-63-153526, the motor is stopped at a target position.
Prepare the deceleration curve data to stop
The data of the deceleration curve and the actual shooting lens
Compare motor speed with motor on / off / brake mode.
Technology that determines the drive mode of the
The art is disclosed. [0003] In addition, a movable unit movable by a motor.
As a motor drive control device for controlling the drive of
Japanese Patent Application Laid-Open No. 4-88412 discloses that a photographic lens is located near an in-focus position.
If the motor is on at the point when
Limit the motor-on time to prevent
Prior art is disclosed. [0004] In addition, a movable unit movable by a motor.
As a motor drive control device for controlling the driving of the
Japanese Patent Publication No.-282213 discloses a mobile device using fuzzy control.
When driving the unit, it stops just before the target position
Apply a predetermined voltage to the motor or turn on the motor for a predetermined time.
Prior art that restarts by doing
Is disclosed. SUMMARY OF THE INVENTION [0005]
In the technology disclosed in JP-A-63-153526,
As the deceleration curve data used for motor control,
Stops when braking at maximum speed
Data of the relationship between motor speed and pulse up to
Ideally, However, in this prior art, the mode under control is controlled.
The motor drive voltage is decelerated to stop at the target position.
When the motor is running and accelerating
During deceleration control, the deceleration curve
Reduces the current motor speed, and selects motor-on
If you do, the motor speed will increase too much,
Increase the deceleration curve area to absorb the speed change.
And the actual driving time becomes longer.
Problem. In this prior art, the acceleration control is reduced.
If the driving voltage is divided into two during speed control, actual driving
When the number of pulses is less than the number of pulses required for deceleration control
Selected the drive voltage for deceleration control from the beginning,
There is a problem that the running time becomes longer. [0008] These problems are described in Japanese Patent Application Laid-Open No.
4-88412 and JP-A-2-282213
Exist as similar issues in the prior art disclosed in
are doing. The present invention has been made in view of the above circumstances.
Therefore, drive control of the movable unit that is movable by the motor
The drive time during deceleration control becomes longer.
In order to avoid
The number of checks determines whether the motor is in acceleration or deceleration control.
The first drive voltage in the acceleration region, and the first drive voltage during the deceleration control.
Driving with a second driving voltage lower than the voltage of
Deceleration curve without high voltage during deceleration control
Driving time until target stop due to reduced speed fluctuation
Motor drive control that makes it possible to reduce power consumption
It is intended to provide a device. According to the present invention, the above section
To solve the problem, (1) move by motor
The movable unit and the pallet according to the movement of the movable unit
Pulse generating means for outputting a pulse
The moving speed of the above movable unit is determined by the pulse output from
Output from the speed detection means for detecting the
Count the number of pulses applied
Position detecting means for detecting a position;
Setting means for setting a movement target position;
Mode according to the output from the step, speed detecting means and setting means.
Multiple drives including ta on, motor off, motor brake
A motor that selects one of the forces and outputs it to the motor
A driving mode selecting unit, and the movable unit among the plurality of driving forces
The number of times the brake has been selected since the unit started
Means for counting the number of brakes to start
Less when motor-on is selected by dynamic bear selection means
The voltage applied to the motor from two or more voltage values
And a motor drive voltage determining means for selecting.
The motor drive voltage determining means is the motor drive mode selecting means.
If motor-on is selected, the brake count
The number of brakes counted by the
At the time of lowering, the first voltage is applied to the motor,
When the number of rakes is equal to or greater than a predetermined number, the first voltage
Applying a lower second voltage to the motor.
A motor drive control device is provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.
The embodiment will be described. FIG. 1 shows a motor according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a conceptual configuration of a drive control device. In FIG. 1, reference numeral 1 denotes a motor.
The pin of the zoom camera as a movable unit
This is a photographic lens optical system that adjusts the shooting position. Reference numeral 2 denotes the above-mentioned photographing lens optics.
A motor that drives the system 1 and rotates the motor 2 forward
And the taking lens optical system 1 performs the extension operation, and
When the motor 2 is driven in reverse, the photographing optical system 1
Perform the operation. Reference numeral 3 indicates the drive of the motor 2
This is a motor drive means for causing Reference numeral 4 denotes a drive of the motor 2.
Pulse generating means for outputting a pulse signal according to the amount
You. Further, reference numeral 5 denotes the photographing optical system 1.
Output from the pulse generating means 4 according to the driving direction
By subtracting or adding pulse signals,
The position of the photographing optical system 1 is detected, and the remaining pulses to the target position are detected.
This is a position detecting means for calculating the number of pulses. Reference numeral 6 denotes the pulse generating means.
Detecting the pulse width of the pulse signal output from 4.
Speed detection for detecting the moving speed of the photographing optical system 1
It is an exit means. Reference numeral 7 denotes the speed detecting means 6.
From the speed of the photographing optical system 1 obtained in
Number of brake overrun pulses required to stop
Is calculated, and the distance to the target position calculated by the position detecting means 5 is calculated.
By comparing with the number of remaining pulses, the motor 2
Either ON, OFF, or brake drive
It is a motor drive mode determining means for determining the mode. Reference numeral 8 denotes a drive of the motor 2.
From the start, the motor drive mode
The number of brakes that counts the number of times the rake is selected
Und means. Reference numeral 9 denotes the motor driving mode.
When the motor-on is selected by the determination means 7,
Motor drive for determining a drive voltage for driving the motor 2
Voltage determining means, wherein the motor drive voltage is at least
Has two or more voltage values
Accelerated by the number of brakes counted by step 8
By judging whether it is in the area or under deceleration control,
The driving voltage applied to the data 2 is determined. FIG. 2 shows the photographing optical system 1, motor 2 and
FIG. 3 is a perspective view showing a configuration of a pulse generation unit 4. In the vicinity of the motor 2, a photo interrupter
(Hereinafter abbreviated as PI) Configuration having 25 and light blocking member 26
Is provided. The rotational force of the motor 2 is transmitted through the reduction gear train 11a.
Gear section 1a provided on the outer periphery of the photographing optical system 1
Is transmitted to When the motor 2 is driven to rotate, the pulse
The light-shielding member 26 that constitutes the source generating means 4 rotates, and PI2
5 outputs a pulse. Then, the photographing optical system 1 rotates around the optical axis O.
1, the lens group holding frame 1 b in the photographing optical system 1
Move back and forth along the optical axis O. FIG. 3 shows a motor drive control device according to the present invention.
Block diagram showing the conceptual configuration of a zoom camera to which
FIG. The CPU 101 corresponds to the control means.
Microcomputer that controls the operation of the entire camera
Sequence control of the zoom camera, auto focus
Cas / Auto Exposure (abbreviated as AF / AE)
Computing), analog-digital (AD) conversion, liquid crystal display
(LCD) panel control, light emitting diode display (L
ED) Control and switch control. The LCD panel 102 displays the number of film frames,
The camera mode, time, battery check result, etc.
Each is a liquid crystal display device for displaying. The switch (SW) operation unit 103 is
Activates when the button is pressed halfway and locks AF and AE.
1st stage switch 1RSW and release button fully pressed
Second-stage switch for shutter release
2RSW, a zoom-up switch ZUPSW,
Zoom down switch ZDNSW and camera
A flash SW for changing the light emitting state of the
Remote controller and self-timer function can be used.
To switch the display between self-swap and date
Mode SW, set S to correct date time
W and power S for switching on / off the power of the camera
W and rewind for forced rewind to rewind during shooting
Switch RWSW and the camera's back cover is closed.
Back cover open / closed state detection switch BKS that detects and performs idle feeding
W. The AF-IC 104 is an IC for AF distance measurement.
And an image is taken based on a control signal from the CPU 101.
Find the distance to the body, and use the serial data bus to
Transfer to U101. The EEPROM 105 is electrically erasable.
The number of frames on the film and the zoom lens change
Position pulse, flash charging voltage information, battery
Various adjustment values such as terror check information are stored. The flash unit 106 is provided with the CPU 1
When a charge signal is given from 01, charging is started. The charging voltage is sent to the CPU 101.
After being sequentially sent and AD changed, it is stored in the EEPROM 105.
It is compared with the stored charging voltage information to determine whether charging is complete.
Is checked. The LED display unit 107 displays a flash emission warning,
Light emitting diode display to notify photographer of AF lock etc.
Place. The IF-IC 109 is an interface I
C, LED drive circuit, photometric element (SPD) 108
Metering circuit, motor drive circuit, reference voltage
It is composed of a pressure circuit and the like. The motor driving IC 110 is the motor of FIG.
It corresponds to the driving means 3. The motor drive sent from the CPU 101
The motion signal is decoded once in the IF-IC 109.
After that, it is supplied to the driving IC. Then, according to the signal of the CPU 101,
Winding / zoom (W / Z) mode corresponding to motor 2
Motor 111, LD motor 112,
Winding the drive of the W / Z motor 111
Switching plunge 114 for switching between lifting and zooming
Is selected and driven. In the vicinity of the LD motor 112, the LD
A forge that generates an output signal in conjunction with the rotation of the motor 112
The interrupter 115 is provided, and its output signal is
Input to the CPU 101 through the IF-IC 109
And controls the LD motor 112 based on the input signal.
I do. Photo interrupter for shutter (AEP
I) 116 is when the power is supplied to the shutter plunger 113.
Thus, a signal synchronized with the opening and closing of the sector is output. The clutch PI 117 is connected to the W / Z motor 11
1 is transmitted to a position where zoom up / down is possible.
If it is turned on, it becomes transparent and outputs an ON signal.
The film is transferred to a position where film winding / rewinding is possible.
If so, the light is shielded and an off signal is output. In the vicinity of the W / Z motor 111, the W / Z
/ Z motor 111 generates an output signal in conjunction with rotation
Photo interrupter (hereinafter abbreviated as motor PI) 34
And the output signal passes through the IF-IC 109.
And input to the CPU 101, based on the input signal.
And controls the motor PI34. The driving force of the W / Z motor 111 is on the feeding side.
Is transmitted to the motor PI34 and the film
Perforation of the film
Photoreflector (WPR) 120 that outputs a signal
Controls the W / Z motor 111. The driving force of the W / Z motor 111 is zoomed.
To the motor PI34 and the motor PI34.
Based on the ZPR119 output signal that outputs the absolute position of the
It is controlled by the CPU 101. The DX code 117 of the film corresponds to the CPU 1
01 directly, and the calculated value to determine the exposure value
It is used as FIGS. 4 and 5 show the zoom camera shown in FIG.
Power of the main CPU 101 when the power is turned on
It is shown to explain the on-reset subroutine procedure.
FIG. That is, the power of the zoom camera shown in FIG.
When the power source (battery) is turned on, the CPU 101 is reset.
Then, the operation of the zoom camera is started. In the initial setting of step S101, the CPU
Initial setting of each board and RAM in 101 is performed. In the battery check in step S102,
Indicates the status of the battery (battery) in the zoom camera.
Is clicked. Here, when the battery voltage is insufficient,
Shows a state without a battery on the LCD panel 102 for a predetermined time.
After that, the operation of the camera is prohibited. In step S103, the EEPROM 10
5, the data stored in the CPU 101 is read out.
In the RAM. In step S104, the inside of the zoom camera
To initialize the mechanic state of the W / Z motor 11
Switch the driving force of 1 to the zoom side and move the lens frame to the retracted position
Move. In step S105, the state of the power SW
Is checked. Here, in the case of power off, step
Jump to S109. If the power is on, the S step
At 106, the number of frames and the state of the mode are displayed on the LCD panel 102.
Let me show you. In step S107, the mirror frame is moved to the collapsed position.
Drive to a wide position where shooting is possible. In step S108, the flash charging is completed.
If not, charge the strobe. In step S109, each SW state is read.
Be included. Hereinafter, S read in step S109
The zoom camera is operated based on the state of W. In step S110, the state of the power SW
When the power is off, the zoom camera
Jumps to step S127 because it is locked
Let it. In step S111, 1RSW is pressed.
Is checked. Here, when 1RSW is pressed, the switch is pressed.
A release sequence after step S112 is performed. In step S112, a battery check is performed.
Is performed and the battery voltage remains until the release sequence ends.
Is checked. Here, when the battery voltage is lower than a predetermined voltage,
In this case, the zoom camera is locked. In step S113, photometry is performed, and
The luminance of the object and the peripheral luminance are measured. In step S114, the current strobe
The charging voltage is checked to see if the flash can be used.
Is clicked. In step S115, the distance to the subject
Is measured. In step S116, step S113
Luminance information, charging voltage information, to the subject up to S115
Shutter opening time, strobe emission,
LDP for light emission time and moving distance of focus lens
It is converted as the number of delivery pulses at I. In step S117, 2RSW is pressed.
A hard check is performed. Here, when 2RSW is not pressed,
Or it is not ready for exposure (for strobe
Nevertheless, if the charging voltage has not reached
Indicates that the subject is too close to focus.
In the case of, the process jumps to step S118. In step S118, 1RSW is checked.
Release shutter if 1RSW is released
After passing through the cans, return to step S109 and continue to be pressed
If so, the process returns to step S117, where 2RSW
Is detected. Here, 2RSW is pressed in the state where exposure is possible.
If it is determined in step S119 that the
Adjust the AF lens by the amount that the focus is adjusted.
Let out. In step S120, the shutter plunge
The shutter 113 is turned on to expose the film. In step S121, step S119
The AF lens is extended and the lens is extended and reset.
The work is done. In step S122, one frame of the film is
After winding, the process returns to step S109. In step S123, the zoom-up switch
Or check if the zoom down switch is pressed
It is. Here, the zoom up switch or the zoom
If the down switch is operated, the process proceeds to step S124.
Zoom operation is performed, and after the zoom operation ends,
In step S125, which returns to step S109, the flash
Checks whether the menu switch or mode switch has been pressed
It is. Here, when any switch is pressed,
In this case, the process proceeds to step S126, and
After the mode of the camera is switched in step S10,
Return to 9. In step S127, rewind (R
W) It is checked whether the SW has been pressed, and the RWSW
If pressed, the film is wound in step S128.
A return operation is performed. In step S129, the change in BKSW is
A check is made to see if there is any. Here, when there is a change in BKSW,
Proceeds to step S130, and detects that the back cover is open
In step S131, the process of opening the back cover is performed. When the back cover is closed, the step
In step S132, an idle feeding operation of the film is performed. In step S133, the power SW is turned off.
Is checked and the power switch is off
In step S134, the collapsing process is performed.
Thereafter, the process jumps to step S136. In step S135, various switches are operated.
The camera has been operated for a predetermined time.
If not, the process proceeds to step S136,
If the time has not elapsed, the process returns to step S109
Thus, the above operation is repeated. In step S136, the display on the LCD is turned off.
Off. In step S137, power SW, BK
SW, rewind SW only interrupts are enabled,
Enter the backup state. Here, power SW, BKSW, RWSW
If there is a change in the stop state, the process exits the stop state and proceeds to step S1
From 02, the operation of the zoom camera is started. FIGS. 6 and 7 show steps S119 and S119.
Flow shown to explain the AF lens extension procedure
It is a chart. FIGS. 8 and 9 show steps S119 and S119.
The timing shown to explain the AF lens extension procedure
FIG. FIG. 8 shows that the actual number of delivered pulses is reduced.
Time when driving more pulses than required for speed control
It is a chart. FIG. 9 shows that the actual number of delivered pulses is decelerated.
Time chart when the number of pulses required for control is less than
It is. That is, in the initial setting of step S150,
Is for LDPI on and LDPI threshold level setting
Start, start of pulse width measurement timer, pulse width limit
CP for counting the LDPI pulses
The hard counter of U101 is started. In step S151, the drive power to the target is
The Luth number is calculated. In step S152, a predetermined first drive
The voltage is set, and the motor 111 is turned off in step S153.
And extend the taking lens. As a result, as shown in FIG. 8 and FIG.
LDPI pulse is output according to the amount of rotation of
As a result, the feeding speed of the taking lens is accelerated. In step S154, the change in LDPI is
A check is made to see if there is any. Here, when there is no change in LDPI,
Jumps to step S155. In step S155, LD
If no change in the PI signal is obtained,
Restart to gradually increase pressure and increase motor torque
Processing is performed. In step S156, restart processing is performed.
If no change in LDPI is obtained for
In step S157, the camera is locked as damage. If the predetermined time has not elapsed,
Returning to step S154, the LDPI change is checked.
It is. In step S154, a change in LDPI is obtained.
If so, the LDPI is counted in step S158.
Is performed. In step S159, the movable unit is moved.
The pulse width of the LDPI indicating the dynamic speed is measured. In step S160, step S158
The number of remaining drive pulses is greater than the actual number of drive pulses read in
Is calculated. In step S161, the remaining drive pulses
Check that the number has reached the number of pulses required for deceleration control.
It is. Here, the remaining pulse is the pulse of the deceleration control.
If the number of shooting lenses is more than
Since there is no need, driving of the photographing lens is started in step S162
Is applied to the motor 111, and
Returning to S154, the count of LDPI is continued (FIG. 8).
A region). The number of remaining pulses is the number of pulses in the deceleration control area.
If the following occurs (line B in FIG. 8),
When the output pulse is less than the deceleration control area pulse (Fig.
In 9), the process proceeds to step S163. In step S163, the target number of pulses is driven.
A check is made to see if it has been done. Here, when driving to the target position,
In step S164, the motor brake is applied and the process ends.
You. When the motor is not driven to the target position,
Proceeds to step S165. In step S165, step S159
The motor 111 from the speed of the taking lens
The number of brake overrun pulses when the
Can be The number of overrun pulses of the brake is
The number of brake overrun pulses at each speed is EE
PROM115 or ROM on CPU101
The number of overrun pulses to be obtained is E
Data on the ROM of the EPROM 115 or the CPU 101
Is calculated by performing an operation such as linear interpolation on the data. In step S166, step S165
And the number of brake overrun pulses calculated in
The number of remaining pulses calculated in step S160 is compared. Here, the number of remaining pulses is
If there are more than two
Jump to step S169 because there is no
The determination of the data drive mode is performed. When the number of remaining pulses is larger than the brake
If the number is less than the number of ramp pulses,
In step S167, the
Brake on the data 111. In step S168, a brake is selected.
The process returns to step S154 to continue the process.
I can. In step S169, the number of remaining pulses and the
The difference from the number of overrun pulses is checked. Here, the remaining pulse number and the overrun
If the difference in the number of motors is within the specified
Stop at the target pulse until
In step S170, the motor is turned off, and the process returns to step S154.
You. Also, the number of remaining pulses and the overrun pulse
If the difference between the numbers is equal to or greater than the predetermined value,
The motor may stop just before the mark position.
The process proceeds to step S171 in order to turn 111 on. In step S171, step S1
Check the number of brakes counted at 68
Is Here, the brake rotation from the start of motor driving is performed.
If the number is less than the specified value, the remaining
The number of pulses has not been reached, or the drive pulse has been decelerated.
Less than pulses and still accelerating motor 111
In the state (FIG. 8), the startup is started in step S172.
After turning on the motor 111 with the first drive voltage at the start,
It returns to step S154 and continues processing. Further, when the brake count number is equal to or larger than a predetermined value.
If the motor is turned on during deceleration control,
In step S172, the first power
Motor 111 was turned on at a second drive voltage lower than the pressure
Thereafter, the process returns to step S154 to continue the above processing. According to the present invention, the brake from the start of driving
Judgment of motor acceleration state and deceleration control by number of times
However, the first drive voltage is used in the acceleration region, and the first drive voltage is used during the deceleration control.
By driving with a second drive voltage lower than the voltage of
High voltage is not applied during deceleration control and the
To reduce the speed fluctuation and shorten the drive time until the target stop.
It becomes possible to reduce. Therefore, as described above, the present invention
According to the system, the movable unit driven by the motor
Control time is long during deceleration control.
In order to avoid the
Whether the motor is in acceleration or deceleration control is determined by the number of rakes.
Judgment is made at the first drive voltage in the acceleration region, and during the deceleration control.
By driving with a second drive voltage lower than the first voltage,
Deceleration curve without high voltage during deceleration control
Driving time until target stop due to reduced speed fluctuation
Motor drive control that makes it possible to reduce power consumption
An apparatus can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a conceptual configuration of a motor drive control device according to an embodiment of the present invention. FIG. 2 is a perspective view showing a configuration of a photographing optical system 1, a motor 2, and a pulse generator 4 of FIG. FIG. 3 is a block diagram showing a conceptual configuration of a zoom camera to which the motor drive control device according to the present invention is applied; FIG. 4 is a flowchart for explaining a procedure of a power-on reset subroutine of a main CPU 101 when power is supplied to the zoom camera shown in FIG. 3; FIG. 5 is a flowchart illustrating a procedure of a power-on reset subroutine of a main CPU 101 when power is applied to the zoom camera illustrated in FIG. 3; FIG. 6 is a flowchart illustrating a procedure of extending an AF lens in step S119 of FIG. 4; FIG. 7 is a flowchart illustrating a procedure of extending an AF lens in step S119 of FIG. 4; FIG. 8 is a timing chart for explaining a procedure of extending an AF lens in step S119 in FIG. 4, and is a time chart when the actual number of pulses to be extended is greater than the number of pulses required for deceleration control; It is a chart. FIG. 9 is a timing chart for explaining a procedure of extending an AF lens in step S119 in FIG. 4, and is a time chart in a case where the actual number of pulses to be extended is smaller than the number of pulses required for deceleration control. is there. [Explanation of Signs] 1 ... photographing lens optical system (movable unit), 2 ... motor, 3 ... motor drive means, 4 ... pulse generation means, 5 ... position detection means, 6 ... speed detection means, 7 ... motor drive mode determination Means 8 ... Brake frequency counting means 9 ... Motor drive voltage determining means

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 7/08 G02B 7/08 Z G05D 3/12 305 G05D 3/12 305V H02P 3/06 H02P 3/06 CF term (reference) 2H020 MA02 MA05 MC22 MC59 MC62 MC71 MC77 ME12 ME15 ME16 ME17 ME38 2H044 DA01 DC08 5H303 AA30 BB02 BB06 CC04 DD01 EE03 EE07 FF09 HH07 JJ02 KK22 LL03 MM02 5H530 AA01 BB40 CC13 CD10

Claims (1)

Claims: 1. A movable unit movable by a motor, pulse generating means for outputting a pulse in accordance with the movement of the movable unit, and a pulse output from the pulse generating means for controlling the movable unit. Speed detecting means for detecting a moving speed; position detecting means for counting the number of pulses output from the pulse generating means to detect the position of the movable unit; and setting for setting a movement target position for the movable unit. Means for selecting one of a plurality of driving forces including a motor on, a motor off, and a motor brake in accordance with outputs from the position detecting means, speed detecting means, and setting means, and outputting the selected driving force to the motor. Counting the number of times a brake has been selected from the start of driving of the movable unit among the plurality of driving forces. Rake number counting means, and motor drive voltage determination means for selecting a voltage to be applied to the motor from at least two or more voltage values when motor-on is selected by the motor drive type bear selection means, The drive voltage determining means applies a first voltage to the motor when the number of brakes counted by the brake number counting means is equal to or less than a predetermined number when the motor-on is selected by the motor drive mode selecting means. A motor drive control device, wherein a second voltage lower than the first voltage is applied to the motor when the number of times of braking is equal to or more than a predetermined number of times.