CN114500863A - Motor drive control method for P-IRIS aperture of camera - Google Patents
Motor drive control method for P-IRIS aperture of camera Download PDFInfo
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- CN114500863A CN114500863A CN202210077265.6A CN202210077265A CN114500863A CN 114500863 A CN114500863 A CN 114500863A CN 202210077265 A CN202210077265 A CN 202210077265A CN 114500863 A CN114500863 A CN 114500863A
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- 238000000034 method Methods 0.000 title claims abstract description 14
- 230000005284 excitation Effects 0.000 claims abstract description 22
- 238000004891 communication Methods 0.000 claims description 3
- 230000002093 peripheral effect Effects 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 abstract description 3
- 230000007547 defect Effects 0.000 description 2
- 230000010363 phase shift Effects 0.000 description 2
- 206010037660 Pyrexia Diseases 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/70—Circuitry for compensating brightness variation in the scene
- H04N23/73—Circuitry for compensating brightness variation in the scene by influencing the exposure time
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- Diaphragms For Cameras (AREA)
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Abstract
The invention relates to the technical field of camera diaphragm control, in particular to a motor drive control method of a camera P-IRIS diaphragm, which adopts a half-step phase shifting mode to solve the problems of excitation zero point and heating caused by overlarge motor excitation current in the existing mode, uses the existing main control and micro-step drive chips to control a motor of the P-IRIS diaphragm, performs half-step phase shifting on the initial state of the chip, and leads sine waves and cosine waves output by the chip to take pi/4 as the starting point of the control motor and take pi/2 as the stepping length in each step. According to the invention, the P-IRIS aperture is driven by the micro-step driving chip, so that the circuit complexity is reduced, the cost is reduced, the occupied area of the PCB is reduced, the excitation zero point can be avoided, the excitation voltage is reduced, the motor position is kept, meanwhile, the heating of the motor is reduced, and the burning of the module is avoided.
Description
Technical Field
The invention relates to the technical field of camera aperture control, in particular to a motor drive control method of a camera P-IRIS aperture.
Background
The existing lens with the accurate aperture (P-IRIS) needs to be driven (bipolar drive) by a full-bridge motor driving circuit, as shown in the following figure, one MCU, two pre-driving modules and two MOS bridges are needed to generate the current and time sequence relation required by the rotation of the motor, so as to drive the motor to rotate. The defects of complex circuit, high cost, large PCB area occupation and the like exist.
After the P-IRIS aperture motor is driven, excitation is needed to keep the position of the motor, otherwise, the motor rebounds, and the fault of large and small steps occurs. The excitation keeping of the bipolar driving mode can enable the current of the motor to be always in the maximum state in the whole life cycle, and the motor is easy to overheat and even burn.
Disclosure of Invention
In order to solve the problems, the invention provides a motor drive control method of the P-IRIS aperture of the camera, which adopts a half-step phase shifting mode and avoids excitation zero and overheating burnout.
In order to achieve the purpose, the invention adopts the following technical scheme:
the motor drive control method of the P-IRIS aperture of the camera comprises a main control chip, a micro-step drive chip, the P-IRIS aperture and an aperture motor, wherein the initial state of the micro-step drive chip is subjected to half-step phase shifting;
the master control chip is in communication connection with the micro-step driving chip through an SPI (serial peripheral interface), sends a command of motor driving control to the micro-step driving chip, analyzes a frame synchronization signal and sends the frame synchronization signal to the micro-step driving chip so as to trigger an aperture motor to act;
the micro-step driving chip controls an internal full-bridge motor driving circuit according to a motor driving control instruction and a frame synchronization signal, the diaphragm motor rotates through an A-phase coil and a B-phase coil in the diaphragm motor to open and close the P-IRIS diaphragm, the P-IRIS diaphragm can adopt a diaphragm in the prior art, main components comprise a diaphragm motor, a gear box and blades, the diaphragm motor rotates and is driven to the blades through the gear box, and the blades move in opposite directions/opposite directions to realize opening and closing of the diaphragm.
Optionally, in an embodiment of the present invention, the frame synchronization signal frequency is 40Hz, and the frame synchronization signal is obtained by analyzing the image data provided by the image sensor in the camera by the main control chip.
Optionally, in an embodiment of the present invention, the half-step phase shift driving mode is specifically that pi/4 of sine waves and cosine waves output by the micro-step driving chip is used as a starting point of the control motor, and pi/2 of the aperture motor is used as a step length.
Optionally, in an embodiment of the present invention, when the aperture motor is in the initial state, the magnitudes of the excitation currents of the phase a coil and the phase B coil are:
|IA0|＝Imax*sin(π/4)＝0.707*Imax
|IB0|＝Imax*cos(π/4)＝0.707*Imax。
optionally, in an embodiment of the present invention, the aperture motor starts from an initial state, stops driving after the nth step is completed, and keeps excitation in a state where driving is completed, where the magnitudes of the excitation currents of the a-phase coil and the B-phase coil are:
the value of the current step number n is substituted into the above formula, and the excitation current of the current step number is 0.707 × ImaxThe size of exciting current has been reduced, when the diaphragm motor does not act, can keep diaphragm motor position, reduces the calorific capacity of diaphragm motor coil, avoids the motor because the risk of generating heat and damage.
The invention has the beneficial effects
1. The motor drive control method of the camera P-IRIS aperture can adopt the existing main control chip and micro-step drive chip, thereby saving the technical research and development cost;
2. the same micro-step driving chip is used together with the focusing motor and the zooming, so that the circuit cost and the complexity are reduced, the installation space of a circuit board is reduced, and the volume of the camera is conveniently reduced;
3. the initial state of the micro-step driving chip is subjected to half-step phase shifting, so that the excitation voltage is kept at 0.707 times of the maximum voltage, the excitation zero point can be avoided, the excitation voltage is reduced, the heating of the diaphragm motor is reduced while the position of the diaphragm motor is kept, and the burning of the module is avoided.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic view of a diaphragm motor according to embodiment 1 of the present invention;
FIG. 2 shows a truth table of driving the aperture motor according to embodiment 1 of the present invention;
FIG. 3 is a schematic view of a bipolar driving mode according to embodiment 1 of the present invention;
FIG. 4 is a schematic waveform diagram of a half-step phase-shifting driving method according to embodiment 1 of the present invention;
Detailed Description
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout, which are exemplary and are intended to be illustrative only and not to be construed as limiting the invention, and, therefore, the description is for the purpose of illustration only and, therefore, the practice of the inventive concepts herein is not limited solely to the exemplary embodiments described herein and the illustrations in the drawings, and, further, the drawings are not intended to be limiting.
Example 1
As shown in FIG. 1, A + is the positive pole of the phase A coil, A-is the negative pole of the phase A coil, B + is the positive pole of the phase B coil, B-is the negative pole of the phase B coil, and H, L is the English abbreviation for current height.
As shown in fig. 2, the initial state of the aperture motor (step 0): the current of the A-phase coil flows from A + to A-, the current of the B-phase coil flows from B + to B-,
the first step is as follows: the current of the A-phase coil flows to A + from A-, and the current of the B-phase coil flows to B-from B +, and the rotor rotates anticlockwise by a fixed angle under the action of magnetic field force.
The second step is that: the current of the A-phase coil flows to A + from A-, and the current of the B-phase coil flows to B + from B-, and the rotor rotates anticlockwise by a fixed angle under the action of magnetic field force.
The third step: the current of the A-phase coil flows to A + from A +, the current of the B-phase coil flows to B + from B +, and the rotor rotates anticlockwise by a fixed angle under the action of magnetic field force.
As shown in fig. 3, where light color indicates the current of the a-phase coil and dark color indicates the current of the B-phase coil. The round dots represent the excitation currents of the phase A and the phase B after each step, the driving mode has the defects of complex circuit, high cost, large occupied area of a PCB and the like, and the excitation current can be always kept at the maximum current Imax. This can cause the motor to be in the maximum state all the time in the whole life cycle, and the result that the fever is serious even burns out the motor is produced.
Therefore, aiming at the existing problems, the existing motor drive control mode is optimized, and the scheme is as follows:
the motor drive control method of the camera P-IRIS aperture comprises a main control chip, a micro-step drive chip, a P-IRIS aperture and an aperture motor, wherein the initial state of the micro-step drive chip is subjected to half-step phase shifting, and the change of the drive mode is realized by writing a program of the half-step phase shifting drive mode into the micro-step drive chip;
the main control chip is in communication connection with the micro-step driving chip through an SPI (serial peripheral interface), sends a motor driving control instruction to the micro-step driving chip and analyzes a frame synchronization signal, wherein the frequency of the frame synchronization signal is consistent with the image frame rate, in the embodiment, the frequency of the frame synchronization signal is 40Hz, the frame synchronization signal is obtained by analyzing the main control chip according to image data provided by an image sensor in a camera, and the frame synchronization signal is used for triggering an aperture motor to act;
the micro-step driving chip controls an internal full-bridge motor driving circuit according to a motor driving control instruction and a frame synchronization signal, the diaphragm motor rotates through an A-phase coil and a B-phase coil in the diaphragm motor to open and close the P-IRIS diaphragm, the P-IRIS diaphragm can adopt a diaphragm in the prior art, main components comprise a diaphragm motor, a gear box and blades, the diaphragm motor rotates and is driven to the blades through the gear box, and the blades move in opposite directions/opposite directions to realize opening and closing of the diaphragm.
As shown in the figure, the half-step phase-shift driving mode: the sine wave and the cosine wave output by the micro-step driving chip take pi/4 as the starting point of the control motor, and the aperture motor takes pi/2 as the stepping length.
When the diaphragm motor is in an initial state, the exciting currents of the A-phase coil and the B-phase coil are as follows:
|IA0|＝Imax*sin(π/4)＝0.707*Imax
|IB0|＝Imax*cos(π/4)＝0.707*Imax。
the diaphragm motor starts from an initial state, stops driving after the first step is finished, the excitation is kept in a driving finished state, and the excitation current of the A-phase coil and the B-phase coil is as follows:
|IA1|＝Imax*sin(3π/4)＝0.707*Imax
|IB1|＝Imax*cos(3π/4)＝0.707*Imax。
the diaphragm motor starts from an initial state, stops driving after the second step is completed, the excitation is kept in a driving end state, and the excitation currents of the A-phase coil and the B-phase coil are as follows:
|IA2|＝Imax*sin(5π/4)＝0.707*Imax
|IB2|＝Imax*cos(5π/4)＝0.707*Imax。
by analogy, the exciting currents of the A-phase coil and the B-phase coil are both 0.707 × ImaxThe size of exciting current has been reduced, when the diaphragm motor does not act, can keep diaphragm motor position, reduces the calorific capacity of diaphragm motor coil, avoids the motor because the risk of generating heat and damage.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (5)
1. The motor drive control method of the camera P-IRIS aperture is characterized by comprising the following steps: the system comprises a main control chip, a micro-step driving chip, a P-IRIS aperture and an aperture motor, wherein the initial state of the micro-step driving chip is subjected to half-step phase shifting;
the main control chip is in communication connection with the micro-step driving chip through an SPI (serial peripheral interface), sends a motor driving control instruction to the micro-step driving chip and analyzes a frame synchronization signal so as to trigger an aperture motor to act;
the micro-step driving chip controls an internal full-bridge motor driving circuit according to a motor driving control instruction and a frame synchronization signal, and the aperture motor rotates through an A-phase coil and a B-phase coil in the aperture motor so as to open and close the P-IRIS aperture.
2. The motor driving control method of the camera P-IRIS diaphragm according to claim 1, characterized in that: the frame synchronization signal frequency is the same as the frequency of a Bayer array original image, and the frame synchronization signal frequency is obtained by analyzing the main control chip according to image data provided by an image sensor in the camera.
3. The motor driving control method of the camera P-IRIS diaphragm according to claim 1, characterized in that: the half-step phase shifting is that the sine wave and the cosine wave output by the micro-step driving chip take pi/4 as the starting point of the control motor, and the aperture motor takes pi/2 as the stepping length.
4. The motor driving control method of the camera P-IRIS diaphragm according to claim 1, characterized in that: when the diaphragm motor is in an initial state, the exciting currents of the A-phase coil and the B-phase coil are as follows:
|IA0|＝Imax*sin(π/4)＝0.707*Imax
|IB0|＝Imax*cos(π/4)＝0.707*Imax。
5. the motor driving control method of the camera P-IRIS diaphragm according to claim 1, characterized in that: the diaphragm motor starts from an initial state, stops driving after the nth step is completed, keeps the excitation in a driving end state, and the excitation currents of the A-phase coil and the B-phase coil are as follows:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202210077265.6A CN114500863A (en) | 2022-01-24 | 2022-01-24 | Motor drive control method for P-IRIS aperture of camera |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210077265.6A CN114500863A (en) | 2022-01-24 | 2022-01-24 | Motor drive control method for P-IRIS aperture of camera |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101236347A (en) * | 2007-02-02 | 2008-08-06 | 佳能株式会社 | Camera system and lens apparatus |
| JP2010102085A (en) * | 2008-10-23 | 2010-05-06 | Acutelogic Corp | Iris controller and iris control method |
| CN202602794U (en) * | 2012-05-17 | 2012-12-12 | 杭州本立道科技有限公司 | Automatic focus integrated camera device |
| JP2014006536A (en) * | 2013-08-08 | 2014-01-16 | Canon Inc | Lens device and method of controlling the same |
| CN104038686A (en) * | 2013-03-05 | 2014-09-10 | 株式会社日立制作所 | Imaging Device, Motor Driving Device And Imaging Method |
| CN106534660A (en) * | 2015-09-11 | 2017-03-22 | 深圳中集天达空港设备有限公司 | Self-adaptive image shooting method and self-adaptive image shooting device |
| RU2707714C1 (en) * | 2019-01-28 | 2019-11-28 | федеральное государственное бюджетное образовательное учреждение высшего образования "Южно-Российский государственный политехнический университет (НПИ) имени М.И. Платова" | Device for automatic acquisition and processing of images |
-
2022
- 2022-01-24 CN CN202210077265.6A patent/CN114500863A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101236347A (en) * | 2007-02-02 | 2008-08-06 | 佳能株式会社 | Camera system and lens apparatus |
| JP2010102085A (en) * | 2008-10-23 | 2010-05-06 | Acutelogic Corp | Iris controller and iris control method |
| CN202602794U (en) * | 2012-05-17 | 2012-12-12 | 杭州本立道科技有限公司 | Automatic focus integrated camera device |
| CN104038686A (en) * | 2013-03-05 | 2014-09-10 | 株式会社日立制作所 | Imaging Device, Motor Driving Device And Imaging Method |
| US20140253788A1 (en) * | 2013-03-05 | 2014-09-11 | Hitachi, Ltd. | Imaging device, motor driving device and imaging method |
| JP2014006536A (en) * | 2013-08-08 | 2014-01-16 | Canon Inc | Lens device and method of controlling the same |
| CN106534660A (en) * | 2015-09-11 | 2017-03-22 | 深圳中集天达空港设备有限公司 | Self-adaptive image shooting method and self-adaptive image shooting device |
| RU2707714C1 (en) * | 2019-01-28 | 2019-11-28 | федеральное государственное бюджетное образовательное учреждение высшего образования "Южно-Российский государственный политехнический университет (НПИ) имени М.И. Платова" | Device for automatic acquisition and processing of images |
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