CN111765913A - Absolute measuring ring photoelectric encoder based on digital potentiometer - Google Patents
Absolute measuring ring photoelectric encoder based on digital potentiometer Download PDFInfo
- Publication number
- CN111765913A CN111765913A CN202010708227.7A CN202010708227A CN111765913A CN 111765913 A CN111765913 A CN 111765913A CN 202010708227 A CN202010708227 A CN 202010708227A CN 111765913 A CN111765913 A CN 111765913A
- Authority
- CN
- China
- Prior art keywords
- digital potentiometer
- absolute
- encoder
- main control
- control chip
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 claims abstract description 19
- 238000006073 displacement reaction Methods 0.000 claims abstract description 18
- 238000012545 processing Methods 0.000 claims description 15
- 238000005259 measurement Methods 0.000 claims description 5
- 238000001514 detection method Methods 0.000 claims description 4
- 238000004891 communication Methods 0.000 claims description 3
- 238000009434 installation Methods 0.000 abstract 2
- 238000012937 correction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
- G01D5/3473—Circular or rotary encoders
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optical Transform (AREA)
Abstract
An absolute measuring ring photoelectric encoder based on a digital potentiometer relates to the field of photoelectric encoders and solves the problems of large volume, limited rotating speed, complex installation and adjustment and the like of the existing absolute measuring ring photoelectric encoder; the MCU main control chip processes the signals acquired by the AD module to obtain the angular displacement of the encoder; the number of rotation turns of the encoder is converted into the resistance value of the digital potentiometer, and the resistance value of the digital potentiometer is calibrated through the compensation calibration circuit to obtain the corrected resistance value of the digital potentiometer; angular displacement and circle number information obtained by the MCU main control chip are transmitted to a superior system. The photoelectric encoder of the invention has small volume and simple installation and adjustment.
Description
Technical Field
The invention relates to the field of photoelectric encoders, in particular to an absolute measuring ring photoelectric encoder based on a digital potentiometer.
Background
The photoelectric encoder is a digital angle measuring device integrating light, machine and electricity into a whole. The measurement mechanism can be divided into: the present invention is directed to a moire fringe type photoelectric encoder. The coding method can be divided into: incremental, absolute and quasi-absolute. After the absolute photoelectric encoder is powered off, data is not lost, and the power-on is the absolute angular displacement position of one circle. Has the advantages of stable and reliable work and the like, thereby being widely used. However, in many cases, if the linear displacement of the motor needs to be powered down to store the rotation number of the current encoder, the current absolute linear displacement position can be determined only by knowing the rotation number of the last encoder and the absolute angular displacement after the motor is powered up. It is therefore necessary to obtain both an absolute angular displacement of one revolution and an absolute number of revolutions.
At present, the photoelectric encoder with the function of measuring the number of absolute rotating turns and the angle is realized by matching gear transmission with two absolute photoelectric encoding disks, the method needs a high-precision gear transmission mechanism, is large in size, is limited in rotating speed, needs to consider the correction relation between the two absolute photoelectric encoding disks, and is complex to assemble and adjust.
Disclosure of Invention
The invention provides an absolute type measuring ring photoelectric encoder based on a digital potentiometer, which aims to solve the problems of large volume, limited rotating speed, complex assembly and adjustment and the like of the existing absolute type measuring ring photoelectric encoder.
The absolute measuring ring photoelectric encoder based on the digital potentiometer comprises a grating system, a mechanical shaft system and a processing circuit; the processing circuit comprises a photoelectric receiving tube, an MCU main control chip, a digital potentiometer and a compensation calibration circuit;
light emitted by the light source passes through the indication grating and the main grating and is received by the photoelectric receiving tube, a coarse code signal obtained by detection of the photoelectric receiving tube is directly transmitted to the AD module of the MCU main control chip, and a fine code signal obtained by detection is amplified by the amplifying circuit and is transmitted to the AD module of the MCU main control chip;
the MCU main control chip processes the signals acquired by the AD module to obtain the angular displacement of the encoder; converting the number of rotation turns of the encoder into the resistance value of the digital potentiometer, and obtaining the corrected resistance value of the digital potentiometer after the resistance value of the digital potentiometer is calibrated by the compensation calibration circuit;
the invention has the beneficial effects that: the invention is realized by adding a digital potentiometer and a compensation calibration circuit thereof to measure the absolute rotation number and angle during electric signal processing. The method is based on the pure electric signal processing, only a plurality of components are added in the circuit, so that the complex mechanical design and adjustment are avoided, and the size of the encoder is effectively reduced; meanwhile, the output of the digital potentiometer is compensated through the precise voltage stabilization chip, and the counting error of the absolute rotation number caused by the drift of the resistance value of the digital potentiometer is prevented.
The invention adopts a digital potentiometer to realize the measurement of the rotation number of turns of an absolute photoelectric encoder from the angle of electric signal processing. The method does not need to add mechanical parts, and the mechanical structure of the method is consistent with that of a common absolute photoelectric encoder. The extra mechanical debugging process is not added, the requirements on debugging personnel are reduced, and the work efficiency of debugging is improved. Compared with the traditional absolute measuring ring photoelectric encoder based on the gear, the absolute measuring ring photoelectric encoder is small in size and simple to install and adjust.
Drawings
FIG. 1 is a schematic structural diagram of an absolute type measuring ring photoelectric encoder based on a digital potentiometer according to the present invention;
FIG. 2 is a schematic diagram of a processing circuit in the absolute type measuring coil photoelectric encoder based on the digital potentiometer according to the present invention;
FIG. 3 is a circuit diagram of a compensation calibration circuit in the absolute type measuring coil photoelectric encoder based on the digital potentiometer according to the present invention;
FIG. 4 is a flow chart of the application of the absolute type measuring ring photoelectric encoder based on the digital potentiometer.
Detailed Description
First embodiment, the present embodiment is described with reference to fig. 1 to 3, and an absolute type circle-measuring photoelectric encoder based on a digital potentiometer has a composition identical to that of the absolute type photoelectric encoder, as shown in fig. 1, that is, the absolute type photoelectric encoder includes: the grating system, the mechanical shaft system 2 and the processing circuit 3. The grating system and the mechanical axis system 3 are the same as the traditional non-measuring-ring absolute photoelectric encoder, and have no difference. The gear structure and the number of turns of the code wheel are not required to be increased like an absolute type ring measuring photoelectric encoder based on the gear.
The light emitted by the light source passes through the grating pair (the indication grating 4 and the main grating 5), when the main grating 5 rotates along with the mechanical axis 2, the photoelectric receiving tube 6 at the other end receives the light and shade alternate stripes, namely: the moire fringes and the subsequent processing circuit 3 process the moire fringes to obtain the angular position of rotation. Compared with a non-measuring-ring absolute photoelectric encoder processing circuit, the processing circuit 3 is additionally provided with the digital potentiometer and the compensation correction circuit 7 thereof, so that the absolute angle can be obtained when power is on, and the number of rotating rings in the last power failure can be obtained.
The embodiment is described with reference to fig. 2, and an MCU (ARM or DSP) is used as a main control chip, and a 10bit or 12bit analog-to-digital converter is generally provided therein, and is used for communicating with an SPI and a serial port, and the like, so as to meet the signal processing requirement of the absolute type circle measuring photoelectric encoder. The coarse code signal that photoelectric receiving tube 6 detected and obtained directly gives MCU's AD module, and the fine code signal needs to be enlargied, gives the AD module after improving the SNR, and MCU handles the signal that comes in to AD acquisition and obtains the angle displacement. And rotatory number of turns register then converts the resistance of digital potentiometer into, and its size accessible MCU's SPI bus sets up, and general digital potentiometer is 8 bits, if total resistance is 10K, then the resistance increases progressively from 0 ~ 10K omega according to resolution ratio (10K omega/256), if the number of turns is more to exceed 256, then can establish ties a plurality of digital potentiometers, if: after 2 8-bit digital potentiometers with 10K omega are connected in series, the resistance value is 0-20K omega, the resolution is (20K omega/65536), and 65536 circles can be counted at most. The MCU sends the processed angle and turn number information to a superior system through a built-in serial port communication module (UART). Besides, the MCU is also responsible for realizing algorithms such as correction and the like.
In order to ensure the accurate resistance of the digital potentiometer obtained by the MCU, the invention adds a compensation calibration circuit, as shown in FIG. 3: a constant current source is added at two ends of the digital potentiometer, the constant current source provides current I, and the voltage at two ends of the resistance AB which does not drift is VrefSince the resistance values of the resistors at the two ends of AB are fixed, VrefAre known constants; voltage V across resistor BCout. If the resistance drifts, the voltage at two ends of the AD acquisition resistor AB of the MCU is V'refVoltage V 'across resistor BC'outThe voltage V 'across BC collected at this time is required'outAnd calibrating to obtain the voltage at the two ends of the corresponding resistance BC without drifting as follows:
in a second embodiment, the present embodiment is described with reference to fig. 4, and the present embodiment is a method for performing measurement by using the absolute type circle-measuring photoelectric encoder based on the digital potentiometer described in the first embodiment, and the specific process is as follows:
the method comprises the following steps that firstly, after power is on, an MCU is initialized, and in the step, the MCU is required to collect coarse code and fine code signals and carry out processing such as coarse code decoding, fine code subdivision and the like to obtain absolute angular displacement;
and secondly, acquiring and correcting the resistance value of the digital potentiometer, wherein the resistance value is the number of turns of the rotation of the encoder when the power is down last time. The data of the two steps are combined to obtain the rotation angle and the number of turns of the encoder when the power is lost last time.
And thirdly, calculating the rotation angle after electrification, acquiring data in real time by the AD, and carrying out operations such as coarse code decoding, fine code subdivision and the like by the MCU to obtain absolute angular displacement.
And fourthly, judging whether the encoder rotates for a whole circle or not, if the encoder rotates for a whole circle in the forward direction, adding one to the number-of-turns counter, and otherwise, subtracting one, thus realizing the measurement of the number of the rotating turns. The data that the number of turns count obtained is sent for digital potentiometer through the SPI bus, converts resistance value into. Therefore, even if power is lost, the number of turns can be saved in the mode of resistance value. Both realized possessing the photoelectric encoder who measures absolute rotation number of turns and angle function simultaneously.
Finally, the data with the number of turns and angular displacement is sent out through the communication module for use by the superior system 7.
The MCU adopted in the invention is selected as DSP or ARM, and if the space of the circuit board allows the selection of the external AD form of the FPGA, the function can be realized in the same way. The circle measuring method in the invention can also be extended to an image type photoelectric encoder.
Claims (5)
1. The absolute measuring ring photoelectric encoder based on the digital potentiometer comprises a grating system, a mechanical shaft system and a processing circuit; the method is characterized in that: the processing circuit comprises a photoelectric receiving tube, an MCU main control chip, a digital potentiometer and a compensation calibration circuit;
light emitted by the light source passes through the indication grating and the main grating and is received by the photoelectric receiving tube, a coarse code signal obtained by detection of the photoelectric receiving tube is directly transmitted to the AD module of the MCU main control chip, and a fine code signal obtained by detection is amplified by the amplifying circuit and is transmitted to the AD module of the MCU main control chip;
the MCU main control chip processes the signals acquired by the AD module to obtain the angular displacement of the encoder; converting the number of rotation turns of the encoder into the resistance value of the digital potentiometer, and obtaining the corrected resistance value of the digital potentiometer after the resistance value of the digital potentiometer is calibrated by the compensation calibration circuit;
and the angular displacement and the circle number information obtained by the MCU main control chip are transmitted to a superior system.
2. The digital potentiometer-based absolute-type circle-measuring photoelectric encoder according to claim 1, wherein: the resistance value of the digital potentiometer is set through an SPI bus of the MCU main control chip.
3. The digital potentiometer-based absolute-type circle-measuring photoelectric encoder according to claim 1, wherein: the method for calibrating the resistance value of the digital potentiometer by the compensation calibration circuit comprises the following steps:
adding constant current source at two ends of the digital potentiometer, wherein the constant current source provides current I, and when the resistance drift does not occur, the voltage at two ends of the resistance AB is VrefSaid voltage V beingrefAre known constants; the voltage across the resistor BC is Vout(ii) a When resistance drift occurs, the voltage of the AD acquisition module of the MCU main control chip after the drift occurs at the two ends of the resistor AB is V'refVoltage V 'after drift of resistance BC'outAnd a voltage V 'after the drift of both ends of the BC'outAnd calibrating to obtain the voltage at the two ends of the corresponding resistance BC which does not drift as follows:
4. the method for measuring by an absolute type measuring ring photoelectric encoder based on a digital potentiometer according to claim 1, which is characterized in that: the method is realized by the following steps:
after power is on, the MCU main control chip initializes and then acquires coarse code and fine code signals, and performs coarse code decoding and fine code subdivision processing to obtain absolute angular displacement;
step two, the resistance value of the digital potentiometer is collected and corrected by the MCU main control chip, and the resistance value is counted by the number of turns of the encoder in last power failure; taking the absolute angular displacement obtained in the step one as the rotation angle of the encoder when the power is down last time;
calculating the rotation angle after power-on, acquiring data in real time by an AD module, and performing coarse code decoding and fine code subdivision operation by an MCU main control chip to obtain absolute angular displacement;
step four, judging whether the encoder rotates for a whole circle, if the encoder rotates for a whole circle in the forward direction, adding 1 to the number-of-turns counter, otherwise, subtracting 1, and realizing the measurement of the number of the rotating turns; sending the data of the number of rotation turns to a digital potentiometer through an SPI bus, and converting the data into resistance values; the resistance value of the resistor is the number of rotation turns; the photoelectric encoder has the function of measuring the absolute rotation number and the angle.
5. The method for measuring by a digital potentiometer absolute type ring measuring photoelectric encoder according to claim 4, further comprising the step of sending the data of the absolute angular displacement obtained in the step three and the rotation number obtained in the step four to a superior system through a communication module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010708227.7A CN111765913B (en) | 2020-07-22 | 2020-07-22 | Absolute measuring ring photoelectric encoder based on digital potentiometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010708227.7A CN111765913B (en) | 2020-07-22 | 2020-07-22 | Absolute measuring ring photoelectric encoder based on digital potentiometer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111765913A true CN111765913A (en) | 2020-10-13 |
| CN111765913B CN111765913B (en) | 2021-07-06 |
Family
ID=72727162
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010708227.7A Active CN111765913B (en) | 2020-07-22 | 2020-07-22 | Absolute measuring ring photoelectric encoder based on digital potentiometer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111765913B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113922924A (en) * | 2021-10-08 | 2022-01-11 | 中国兵器装备集团自动化研究所有限公司 | Spi-based absolute value encoder communication method and system |
| CN114543852A (en) * | 2021-12-30 | 2022-05-27 | 江苏集萃微纳自动化系统与装备技术研究所有限公司 | Grating signal conditioning circuit, system and method |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203177871U (en) * | 2013-01-31 | 2013-09-04 | 深圳市测力佳控制技术有限公司 | Photoelectric rotation position measurer |
| CN106404207A (en) * | 2016-11-08 | 2017-02-15 | 辽宁师范大学 | Platinum resistance-based wide-range high-precision temperature measuring instrument and measuring method thereof |
| CN208207635U (en) * | 2018-06-20 | 2018-12-07 | 河南驰诚电气股份有限公司 | Electric current self-checking device |
| CN109238177A (en) * | 2018-10-16 | 2019-01-18 | 大连探索者科技有限公司 | A kind of combined type angular transducer with measurement multi-turn angle function |
| CN209605840U (en) * | 2019-03-22 | 2019-11-08 | 扬州大学 | A kind of high-precision hall formula sensor volt age offset compensation device |
| CN111189482A (en) * | 2020-01-13 | 2020-05-22 | 珠海格力电器股份有限公司 | Broken line detection device, encoder and broken line detection method thereof |
| CN111238548A (en) * | 2020-03-05 | 2020-06-05 | 中国科学院长春光学精密机械与物理研究所 | Signal acquisition processing device and method of non-image absolute photoelectric encoder |
| CN111351512A (en) * | 2020-03-13 | 2020-06-30 | 中国科学院长春光学精密机械与物理研究所 | Incremental photoelectric encoder signal processing device and processing method |
-
2020
- 2020-07-22 CN CN202010708227.7A patent/CN111765913B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203177871U (en) * | 2013-01-31 | 2013-09-04 | 深圳市测力佳控制技术有限公司 | Photoelectric rotation position measurer |
| CN106404207A (en) * | 2016-11-08 | 2017-02-15 | 辽宁师范大学 | Platinum resistance-based wide-range high-precision temperature measuring instrument and measuring method thereof |
| CN208207635U (en) * | 2018-06-20 | 2018-12-07 | 河南驰诚电气股份有限公司 | Electric current self-checking device |
| CN109238177A (en) * | 2018-10-16 | 2019-01-18 | 大连探索者科技有限公司 | A kind of combined type angular transducer with measurement multi-turn angle function |
| CN209605840U (en) * | 2019-03-22 | 2019-11-08 | 扬州大学 | A kind of high-precision hall formula sensor volt age offset compensation device |
| CN111189482A (en) * | 2020-01-13 | 2020-05-22 | 珠海格力电器股份有限公司 | Broken line detection device, encoder and broken line detection method thereof |
| CN111238548A (en) * | 2020-03-05 | 2020-06-05 | 中国科学院长春光学精密机械与物理研究所 | Signal acquisition processing device and method of non-image absolute photoelectric encoder |
| CN111351512A (en) * | 2020-03-13 | 2020-06-30 | 中国科学院长春光学精密机械与物理研究所 | Incremental photoelectric encoder signal processing device and processing method |
Non-Patent Citations (1)
| Title |
|---|
| 韩庆阳等: "航天级反射式光电编码器信号处理系统设计", 《红外与激光工程》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113922924A (en) * | 2021-10-08 | 2022-01-11 | 中国兵器装备集团自动化研究所有限公司 | Spi-based absolute value encoder communication method and system |
| CN114543852A (en) * | 2021-12-30 | 2022-05-27 | 江苏集萃微纳自动化系统与装备技术研究所有限公司 | Grating signal conditioning circuit, system and method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111765913B (en) | 2021-07-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111765913B (en) | Absolute measuring ring photoelectric encoder based on digital potentiometer | |
| CN110736486B (en) | Compact dual-redundancy absolute encoder | |
| CN101210821A (en) | Coarse-fine data coupling method for double passage shaft angle conversion and measurement | |
| CN109238177B (en) | Combined type angle sensor with measure many rings of angle functions | |
| WO2003069270A1 (en) | Methods and apparatus for sensing angular position of a rotatable shaft | |
| CN112117079B (en) | Encoder magnet structure, encoder, motor, electrical equipment and vehicle | |
| CN110779556A (en) | Potentiometer full-range angle calibration device and method based on incremental encoder | |
| CN101534630A (en) | Multiturn rotational sensor | |
| Bahn et al. | Digital optoelectrical pulse method for Vernier-type rotary encoders | |
| EP3308107A1 (en) | Positional encoder | |
| CN111006696B (en) | Magnetic encoder and angle calculation method thereof | |
| CN102829714A (en) | Method for realizing absolute angle measurement based on round inductosyn | |
| CN110345976B (en) | Magneto-optical hybrid encoder system | |
| CN111238548B (en) | Signal acquisition processing device and method of non-image absolute photoelectric encoder | |
| CN101846529A (en) | Decoding circuit of spaceborne absolute type photoelectric axial angle encoder based on DSP (Digital Signal processor) | |
| US6950769B2 (en) | Encoder signal interpolation divider | |
| CN109708673B (en) | Separating magnetic encoder based on code pattern | |
| CN219265348U (en) | High-precision hybrid coding device | |
| CN110879408A (en) | CT rotary encoder, CT machine and method for detecting rotation angle of scanning frame | |
| CN111735482A (en) | Absolute value encoder, bit reading method thereof and electronic equipment | |
| CN111368584B (en) | High-resolution position information splicing method of sine and cosine encoder capable of self-correcting | |
| CN210625594U (en) | Quasi-absolute M-code split photoelectric encoder | |
| CN115900781A (en) | Code wheel rotation angle data reading method | |
| CN210774092U (en) | Potentiometer full-range angle calibration device based on incremental encoder | |
| CN114166255A (en) | Vernier absolute type encoder position reading method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |