CN114993356B - Absolute value encoder and position detection method thereof - Google Patents
Absolute value encoder and position detection method thereof Download PDFInfo
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- CN114993356B CN114993356B CN202210421897.XA CN202210421897A CN114993356B CN 114993356 B CN114993356 B CN 114993356B CN 202210421897 A CN202210421897 A CN 202210421897A CN 114993356 B CN114993356 B CN 114993356B
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- 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
- G01D5/12—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 using electric or magnetic means
- G01D5/244—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 using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
- G01D5/245—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 using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains using a variable number of pulses in a train
- G01D5/2451—Incremental encoders
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/003—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring position, not involving coordinate determination
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- 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
- G01D5/353—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 influencing the transmission properties of an optical fibre
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Abstract
The application relates to the field of encoders, in particular to an absolute value encoder, which comprises an installation base body, a magnetic grating and a grating which rotate relative to the installation base body, are arranged on a shaft disc and surround an output shaft of a motor, a magnetic sensing component which is arranged on the installation base body and is used for detecting the position of the magnetic grating and outputting a magnetic increment analog signal, a light sensing component which is arranged on the installation base body and is used for detecting the position of the grating and outputting a light increment analog signal, and a signal processing unit which is arranged on the installation base body and is used for receiving and processing the magnetic increment analog signal and the light increment analog signal and outputting absolute position information, wherein the number of periods of the magnetic increment analog signal output by the magnetic sensing component after the magnetic grating rotates once is N, the number of periods of the light increment analog signal output by the light sensing component after the grating rotates once is M, the N and the M are integers and the numbers of the light increment analog signal are mutually equal to each other, and the M is greater than N, and the N is greater than or equal to 2.
Description
Technical Field
The present application relates to the field of encoders, and more particularly, to an absolute value encoder and a position detection method of the encoder.
Background
Encoders are often used in precision devices provided on automatic equipment such as machine tools for detecting the angle of a correspondingly connected motor output shaft to obtain the state of the component connected to the motor output shaft at that time. The encoder is divided into an absolute value encoder and an incremental encoder, wherein the absolute value encoder has a numerical value corresponding to each angle in the rotation angles corresponding to 360 degrees in one circle, namely, only one period exists, and when the numerical value is detected, the current position of the motor output shaft in the corresponding circle can be obtained. The incremental encoder is used for detecting that the motor output shaft rotates from the zero point through a plurality of pulse periods by setting a plurality of pulse periods, and the position of the motor output shaft in a corresponding circle can be obtained.
The existing absolute value encoder has various realization methods, namely a precise magnetic sensing component can be directly used together with a precise magnetic grating, the magnetic grating can be a magnetic drum which is arranged around an output shaft of a motor, and a precise absolute signal reflecting the angle of the output shaft of the motor can be obtained.
In addition, a coarser magnetic sensing component can be directly used for matching a magnetic grating to obtain a coarser absolute signal, and then a relatively finer grating and a light sensing component are used as assistance, wherein the grating is an array of increment patterns arranged around an output shaft of a motor, each group of increment patterns corresponds to a period, each period can correspond to 1 degree or 0.1 degree, when the light sensing component passes through one group of increment patterns, a corresponding precise increment signal of one period is output, a signal processing unit receives and processes the coarser absolute signal and the precise increment signal, and outputs absolute position information, the absolute position information is divided into a high position and a low position, for example, 10 degrees in 10.55 degrees are the high position, 0.55 degrees are the low position, and the high position in the absolute position information is the position of the magnetic grating at the moment.
For the related art, the inventor considers that the cost of using the precise magnetic sensing component is high, and the coarse magnetic sensing component is further assisted by the optical sensing component, so that in order to reduce errors, two coarse and precise gratings need to be set, one group of increment patterns in the coarse grating corresponds to the array increment patterns in the precise grating, which results in the increase of the number of gratings and the increase of the cost, and has the defect that the cost of the high-precision encoder is high.
Disclosure of Invention
In order to reduce the cost of a high-precision encoder, the application provides an absolute value encoder and a position detection method of the encoder.
In a first aspect, the present application provides an absolute value encoder adopting the following technical scheme.
An absolute value encoder comprising a mounting base; the shaft disc rotates relative to the mounting base body; the magnetic grid is arranged on the shaft disc around the rotation axis of the shaft disc and rotates along with the rotation of the shaft disc; the magnetic sensing component is arranged on the installation base body corresponding to the magnetic grid, and magnetically senses when the magnetic grid rotates and obtains a magnetic increment analog signal; the grating is arranged on the shaft disc around the rotation axis of the shaft disc and rotates along with the rotation of the shaft disc; the optical sensing component is arranged on the mounting substrate corresponding to the grating, and is used for optical sensing when the grating rotates and obtaining optical increment analog signals; and the signal processing unit is used for receiving and integrating the magnetic increment analog signal and the optical increment analog signal so as to obtain absolute position information. The magnetic grating circumferentially rotates along the magnetic grating to be sensed by a circle of magnetic induction detection component and obtains N periods of magnetic increment analog signals; the grating circumferentially rotates a circle of light sensing component to sense and obtain light increment analog signals of M periods; n and M are integers and are mutually prime, M is greater than N, wherein N is greater than or equal to 2; the signal processing unit combines the optical incremental analog signal and the magnetic incremental analog signal to determine a period number of the optical incremental analog signal to obtain absolute position information.
Optionally, the signal processing unit pre-stores values ψn of magnetic incremental analog signals corresponding to the start points of all periods of the optical incremental analog signals, wherein the values ψn are uniformly distributed at equal intervals on all periods of the magnetic incremental analog signals; the signal processing unit obtains a starting point of a period of the optical incremental analog signal and a value psi x of the magnetic incremental analog signal corresponding to the starting point through the optical incremental analog signal and the magnetic incremental analog signal acquired at any time, obtains the psi n equal to the psi x through comparison, namely, determines the period sequence number x of the optical incremental analog signal, the value range of x is 1-M, and then obtains absolute position information.
Optionally, the signal processing unit calculates the optical incremental analog signal to obtain a digital angle θ2, and an absolute position angle θ= (x-1) 360 degrees/m+θ2/M.
By adopting the technical scheme, according to the unique group of optical increment analog signals and magnetic increment analog signals corresponding to each position, the starting point of the period of the optical increment analog signals and the value ψx of the magnetic increment analog signals corresponding to the starting point can be obtained, the period serial number of the optical increment analog signals corresponding to precise absolute position information can be obtained, then the period serial number of the optical increment analog signals is converted into the high position of the absolute position information, namely (x-1) by 360 degrees/M, the position corresponding to the optical increment analog signals in one period is converted into the low position of the absolute position information, namely the digital angle range value (2 pi) of one period of the theta 2/optical increment analog signals, namely theta 2/M, the high position and the low position are added, and then the absolute position information theta is output, so that the output absolute position information is more precise, a plurality of groups of gratings are not needed for achieving absolute value solution, and a magnetic sensing part and a grid with higher absolute position output are not needed.
Optionally, the light sensing component includes a light emitting component disposed on the mounting substrate and emitting stable light toward the grating, and a light receiving component disposed on the mounting substrate and receiving the light periodically changing after passing through the grating and outputting a light increment analog signal.
By adopting the technical scheme, the luminous component does not need to periodically change, and only needs to periodically set on the grating, so that the light passing through the grating periodically changes, the acquisition and output of the light increment analog signal can be realized, and the corresponding manufacturing cost of the luminous component is reduced.
Optionally, the grating includes the printing opacity code wheel of locating the axle dish, locates the array sensitization stripe of printing opacity code wheel, and every group sensitization stripe all at least one light transmission district that supplies light to pass through and at least one non-printing opacity district that prevents light transmission, and the printing opacity district sets up M group around printing opacity code wheel axis of rotation, and every group printing opacity district's setting form is unanimous, and the close sideline coincidence of two adjacent groups printing opacity district, and light receiving subassembly and light emitting component are located the both sides of printing opacity code wheel respectively in order to make the light that light emitting component launched pass the printing opacity district and shine to light receiving subassembly.
Optionally, the light transmission area is rectangular hole or trapezoidal hole that the length direction set up along the radial of printing opacity code wheel, and the printing opacity district is evenly setting around printing opacity code wheel axis of rotation, and the central angle that printing opacity district and non-printing opacity district correspond respectively equals, and the quantity of printing opacity district is M.
By adopting the technical scheme, by means of slit diffraction, after the arrangement of the light transmission area is simplified, a high-quality light increment analog signal with sine and cosine period can be formed.
Optionally, the grating includes the reflection code wheel of locating the axle dish, locates the reflection code wheel and reflects the light that the luminous subassembly launched to the light sense pattern on the receipts optical subassembly, and the light sense pattern sets up M group around reflection code wheel axis of rotation, and every group light sense pattern's setting is unanimous, and adjacent two groups light sense pattern's close sideline coincidence, every group light sense pattern all includes a high reflectance district and a low reflectance district, and the reflection light intensity that receives of receipts optical subassembly is continuous periodic variation from high reflectance district to low reflectance district.
Through adopting above-mentioned technical scheme, rely on the reflection of light to make luminous subassembly and receipts optical subassembly can set up in the same side department of grating, need not to set up luminous subassembly and receipts optical subassembly separately to can take off luminous subassembly or receipts optical subassembly in the lump when the maintenance and examine and repair, it is comparatively convenient.
Optionally, the magnetic grid is formed by splicing a plurality of concentric arc magnets, and the arrangement form of each arc magnet is the same, or the magnetic grid is a magnet formed by magnetizing a whole multipole.
Optionally, the magnetic grid is formed by uniformly distributing a plurality of strip magnets around the rotation axis of the shaft disc, and the magnetic poles at the close ends of two adjacent strip magnets are different.
By adopting the technical scheme, one arc magnet corresponds to one magnetic increment analog signal period, and two adjacent strip magnets correspond to half of the magnetic increment analog signal period, so that the magnetic increment analog signals continuously and periodically change.
Optionally, the magnetic sensing component includes a magnetic sensing device for detecting a change of a magnetic field, and the magnetic sensing device is any one of a magnetic induction chip, a hall element, a magnetoresistance effect sensor, and a giant magnetoresistance sensor.
By adopting the technical scheme, the magnetic sensing component can be used for detecting the magnetic field change so as to output periodic magnetic increment analog signals aiming at the periodically changed magnetic field intensity.
In a second aspect, the present application provides a method for detecting a position of an absolute value encoder, which adopts the following technical scheme.
A position detection method of absolute value encoder, provide an absolute value encoder, including a magnetic grating, a magnetic sensing part, a light sensing part, a grating and a signal processing unit; the magnetic sensing component performs magnetic sensing and obtains a magnetic increment analog signal when the magnetic grid rotates relatively, and the magnetic grid rotates circumferentially for one circle, and the magnetic sensing component senses and obtains N periods of magnetic increment analog signals; the optical sensing component senses light and obtains optical increment analog signals when the grating rotates relatively, and the grating rotates circumferentially for one circle to sense and obtain optical increment analog signals of M periods; wherein N and M are integers and are mutually equal, M is greater than N, and N is greater than or equal to 2; the signal processing unit combines the optical incremental analog signal and the magnetic incremental analog signal to determine a period sequence number x of the optical incremental analog signal to obtain absolute position information.
Optionally, the signal processing unit pre-stores a value ψn of an incremental magnetic analog signal corresponding to the start point of each period of the optical incremental analog signal, and the ψn is uniformly distributed at equal intervals on all periods of the magnetic incremental analog signal; the signal processing unit obtains a corresponding period starting point of the optical increment analog signal and a value psi x of the magnetic increment analog signal corresponding to the starting point through the optical increment analog signal and the magnetic increment analog signal acquired at any time, obtains the psi n equal to the psi x through comparison, namely, determines the period sequence number x of the optical increment analog signal, the value range of x is 1-M, and then obtains an absolute position signal.
Optionally, the signal processing unit calculates the optical incremental analog signal to obtain a digital angle θ2, and an absolute position angle θ= (x-1) 360 degrees/m+θ2/M.
Optionally, the signal processing unit calculates the magnetic increment analog signal to obtain a digital angle θ1; the signal processing unit is used for calculating the optical increment analog signal to obtain a digital angle theta 2; the signal processing unit pre-stores a group of theta 1 and theta 2 corresponding to each absolute position angle theta; the signal processing unit is used for calculating the magnetic increment analog signals acquired at the moment to obtain a data angle theta x and calculating the optical increment analog signals acquired at the moment to obtain a data angle theta y; the signal processing unit retrieves and outputs absolute positions corresponding to θ1 and θ2 which are the same as θx and θy.
By adopting the technical scheme, the absolute position information can be detected by using one magnetic grating and one grating, so that the cost is reduced, and meanwhile, the detection precision can be better ensured.
In summary, the present application includes at least one of the following beneficial effects:
1. The precision of the whole encoder is improved without arranging a plurality of groups of gratings or using a precise magnetic sensing component and a magnetic grating with high manufacturing cost, so that the manufacturing cost of the encoder is relatively low while the whole encoder achieves higher precision;
2. The light emitting component does not need to be periodically changed, and only needs to be periodically arranged on the grating, so that the light passing through the grating is periodically changed, the acquisition and output of the light increment analog signal can be realized, and the corresponding manufacturing cost of the light emitting component is reduced.
Drawings
FIG. 1 is a schematic view of a first embodiment of the present application;
FIG. 2 is a schematic diagram of a magnetic grid according to an embodiment;
FIG. 3 is a schematic diagram of a grating structure according to an embodiment;
FIG. 4 is a schematic diagram of an embodiment in which M is set to 9,N to 2 to assist in determining absolute position information in conjunction with optical and magnetic incremental analog signals;
Fig. 5 is a schematic structural view of a second embodiment;
FIG. 6 is a schematic diagram of a second embodiment of a grating structure;
fig. 7 is a schematic diagram of a structure of a three-magnetic grid according to an embodiment.
Reference numerals illustrate: 1. a shaft disc; 2. a magnetic grid; 21. an arc-shaped magnet; 22. a bar magnet; 3. a grating; 31. a light-transmitting code disc; 32. a light transmission region; 33. a reflective code wheel; 34. light sensitive patterns; 35. a high reflectance region; 36. a low reflectance region; 37. a photosensitive stripe; 38. a non-light-transmitting region; 4. a mounting substrate; 5. a magnetic sensing component; 51. a magnetic induction device; 6. a light sensing part; 61. a light emitting assembly; 62. a light receiving assembly; 7. a signal processing unit; 8. an input shaft.
Detailed Description
The present application will be described in further detail with reference to the accompanying drawings.
Embodiment one:
Referring to fig. 1, the absolute value encoder according to the embodiment of the present application includes a mounting base 4 detachably connected to a side of a motor where an output shaft is disposed, where the mounting base 4 may be a closed casing or a PCBA circuit board, and in this embodiment, the mounting base 4 is a closed casing. The connection mode between the installation base body 4 and the motor can be bolt connection or buckle connection, the installation base body 4 is cylindrical, the installation base body 4 is coaxially connected with an input shaft 8 in a rotating mode, and the input shaft 8 is connected with an output shaft of the motor through a coupler or a gear set. The input shaft 8 is fixedly connected to the shaft disk 1 coaxially at one end in the mounting base 4 such that the shaft disk 1 rotates along with the rotation of the input shaft 8.
Referring to fig. 1, a magnetic grating 2 is fixedly connected to a shaft disc 1 near an axis of the shaft disc, a magnetic sensing component 5 is detachably connected to a position, opposite to the magnetic grating 2, inside a mounting base 4, of the magnetic sensing component 5, the magnetic sensing component 5 comprises a magnetic induction device 51 capable of detecting magnetic field transformation, the magnetic induction device 51 is any one of a magnetic induction chip, a hall element, a magneto-resistance effect sensor, a giant magneto-resistance sensor and a fluxgate sensor, the magnetic induction device 51 faces to the periphery of the magnetic grating 2, the magnetic induction device 51 is electrically connected to an external power supply to detect the periodically transformed magnetic field intensity at the periphery of the rotating magnetic grating 2, and a periodically changed magnetic increment analog signal is output. After the hub 1 rotates one revolution in the circumferential direction thereof, the magnetism sensing device 51 outputs a magnetic increment analog signal of N cycles.
Referring to fig. 1 and 2, the magnetic grating 2 includes a plurality of arc magnets 21 having the same axis as the axis of the spindle disk 1, the arc magnets 21 may be natural magnets or magnetic substances magnetized, the magnetic substances may be ferrite, and each arc magnet 21 is spliced with each other and adhered and fixed by a magnet structural adhesive, such as an acrylic structural adhesive, so that the magnetic grating 2 is in a ring shape. In order to facilitate magnetizing the arc magnets, the adjacent ends of the two adjacent arc magnets 21 are opposite poles, so that when each arc magnet 21 rotates to pass through the magnetic induction device 51, the magnetic induction device 51 can output a magnetic increment analog signal with a period range of sine and cosine periods, namely, the value range of the magnetic increment analog signal with a period is 0-2 pi. In another implementation of this embodiment, the magnetic grid 2 may be formed by magnetizing the entire ring-shaped magnetic material with multiple poles.
Referring to fig. 1, a grating 3 is fixedly connected to an end surface of a spindle disk 1 where a magnetic grating 2 is disposed, the grating 3 is close to a periphery of the spindle disk 1, a light sensing component 6 is detachably connected to an inside of a mounting base 4 facing the inside of the grating 3, the light sensing component 6 includes a light emitting component 61 capable of stably emitting light toward the grating 3, and the light emitting component 61 may be a light emitting diode or a laser diode. The light receiving component 62 is arranged in the mounting substrate 4, the light receiving component 62 can be a photoelectric imaging device, light rays emitted by the light emitting component 61 become periodically-changed light rays after passing through the rotating grating 3 and are received by the light receiving component 62, so that the light receiving component 62 can correspondingly output periodically-changed light increment analog signals, and after the spindle disk 1 rotates for one circle along the circumferential direction of the spindle disk 1, the light receiving component 62 outputs M periodic light increment analog signals.
Referring to fig. 1 and 3, the grating 3 includes a light-transmitting code disc 31 coaxially and fixedly connected to the periphery of the end surface of the shaft disc 1, the diameter of the light-transmitting code disc 31 is larger than that of the shaft disc 1, M groups of photosensitive stripes 37 are arranged around the axis of the light-transmitting code disc 31 beyond the end surface of the shaft disc 1, the light-emitting component 61 and the light-receiving component 62 are respectively positioned at two sides of the light-transmitting code disc 31, and the side lines of two adjacent groups of photosensitive stripes 37 are overlapped, so that no space exists between the output light increment analog signal bands of two adjacent periods. Each set of photosensitive stripes 37 includes at least one light-transmitting region 32 and at least one light-non-transmitting region 38, and light emitted from the light-emitting component 61 can partially pass through the light-transmitting region 32 and be received by the light-receiving component 62. Each group of light-transmitting areas 32 comprises a rectangular or trapezoid light-transmitting area 32, M groups of light-transmitting areas 32 are uniformly distributed around the axis of the light-transmitting code disc 31, the length direction of the light-transmitting areas 32 is parallel to the radial direction of the light-transmitting code disc 31, and the width of each light-transmitting area 32 is the same as the central angle corresponding to the non-light-transmitting area 38. When passing through each light-transmitting region 32, the light-emitting component 61 forms slit diffraction, so that the light-receiving component outputs a light increment analog signal with a period range of sine and cosine, that is, the light increment analog signal with a period ranges from 0 pi to 2 pi.
Referring to fig. 1, a signal processing unit 7 is detachably connected to the outside of the installation base 4, and the signal processing unit 7 receives and processes the magnetic increment analog signal and the optical increment analog signal and outputs absolute position information capable of reflecting the angular position of the motor output shaft. After the output shaft of the motor rotates once, that is, after the input shaft 8 rotates once, the output M and N are mutually equal, M is greater than N, and N is greater than or equal to 2.
Referring to fig. 4, a set of corresponding values are set on each position of 360 degrees of the spindle disk 1 in the periodic magnetic increment analog signal and the optical increment analog signal, the position of the magnetic increment analog signal corresponding to each set of values in one period and the position of the optical increment analog signal in one period are necessarily different, according to the unique set of the optical increment analog signal and the magnetic increment analog signal corresponding to each position, the starting point of the period of the optical increment analog signal and the value ψx of the magnetic increment analog signal corresponding to the starting point can be obtained, the period sequence number x, x of the optical increment analog signal corresponding to the precise absolute position information can be obtained, the value range 1-M is obtained, then the period sequence number of the optical increment analog signal is converted into the high position of the absolute position information, namely (x-1) < 360 degrees/M, the position θ2 corresponding to the optical increment analog signal in one period is converted into the low position of the absolute position information, namely, the digital angle range value of θ2/optical increment analog signal in one period (pi/M), namely, the high position 2 x/M is added, and then the absolute position is added to the high position of the absolute position information (2 x/M), namely, the absolute position is added by 360 x/M.
The implementation principle of the absolute value encoder in the first embodiment of the application is as follows: the absolute position information is determined by using the magnetic grating 2 and the grating 3 which are mutually equal in the period number of the output signal, so that the precise absolute position information can be obtained, and meanwhile, the overall cost of the encoder can be reduced better.
The first embodiment of the application also discloses a position detection method of the absolute value encoder, which uses the absolute value encoder to detect.
Referring to fig. 4, the spindle disk 1 rotates one turn in the circumferential direction, the magnetic sensing part 5 senses and obtains the magnetic increment analog signals of N periods, and the optical sensing part 6 senses and obtains the optical increment analog signals of M periods, N and M are integers and mutually equal, and M is greater than N, N is greater than or equal to 2. In this embodiment, n=2 and m=9 are selected for illustration.
The signal processing unit 7 pre-stores the value ψn of the incremental magnetic analog signal corresponding to each period starting point of the optical incremental analog signal, wherein the value ψn is uniformly distributed at equal intervals on all periods of the magnetic incremental analog signal, the signal processing unit 7 obtains the corresponding period starting point of the optical incremental analog signal and the value ψx of the magnetic incremental analog signal corresponding to the starting point through the optical incremental analog signal and the magnetic incremental analog signal acquired at any time, the value ψn equal to the ψx is obtained through comparison, namely the period sequence number x of the optical incremental analog signal is determined, then the signal processing unit 7 calculates the optical incremental analog signal, and calculates the digital angle theta 2 of y bits, and the absolute position angle theta= (x-1) 360 degrees/9+theta 2/9.
In other implementations of the position detecting method of the absolute value encoder of the first embodiment, the signal processing unit 7 may calculate the magnetic incremental analog signals and calculate the digital angle θ1 of x bits, that is, the number of specific position information that can be resolved by the magnetic sensing unit 5 in one period of the magnetic incremental analog signals is 2x, where 2x is greater than or equal to M, so as to ensure that there is enough ψn in each period of the magnetic incremental analog signals to determine ψx. The signal processing unit 7 is used for resolving the optical incremental analog signals and resolving a digital angle theta 2 of y bits, y is larger than or equal to 2, the signal processing unit 7 is pre-stored with a group of theta 1 and theta 2 corresponding to each absolute position angle theta, the signal processing unit 7 is used for resolving the magnetic incremental analog signals acquired at the moment to obtain a data angle theta x and resolving the optical incremental analog signals acquired at the moment to obtain a data angle theta y, and the signal processing unit 7 is used for calling and outputting absolute positions corresponding to the theta 1 and the theta 2 which are identical to the theta x and the theta y.
The implementation principle of the position detection method of the absolute value encoder in the first embodiment of the application is as follows: the absolute position information is determined by using the magnetic grating 2 and the grating 3 which are mutually equal in the period number of the output signal, so that the precise absolute position information can be obtained, and meanwhile, the overall cost of the encoder can be reduced better.
Embodiment two:
Referring to fig. 5 and 6, the second embodiment of the present application discloses an absolute value encoder, which is different from the first embodiment in that the grating 3 includes a reflective code disc 33 coaxially and fixedly connected to the periphery of the end surface of the shaft disc 1, a light emitting component 61 and a light receiving component 62 are located on the same side of the reflective code disc 33, M groups of light sensing patterns 34 are disposed around the axis of the reflective code disc 33 facing the end surface of the light emitting component 61, the light emitting component 61 emits light onto the light sensing patterns 34, the light sensing patterns 34 reflect the light with consistent incident intensity to form reflected light with inconsistent intensity, and the light receiving component 62 receives the reflected light and outputs the same light increment analog signal in one period corresponding to each group of light sensing patterns 34. The adjacent edges of the two adjacent sets of light sensing patterns 34 coincide, so that no space exists between the two adjacent periodic light increment analog signals output by the light receiving assembly 62.
Referring to fig. 6, each set of light sensing patterns 34 includes a high reflection coefficient region 35 and a low reflection coefficient region 36, and the reflection capability of the high reflection coefficient region 35 to the low reflection coefficient region 36 on light periodically varies in sine and cosine, so that the light receiving component 62 outputs a light increment analog signal with a period range of sine and cosine, i.e. the value range of the light increment analog signal with a period is 0 pi to 2 pi.
An absolute value encoder implementation principle of the second embodiment of the present application is different from that of the first embodiment: the periodic output of the light increment analog signal is realized by utilizing the difference of the reflection intensity of the light rays, so that the light receiving component 62 and the light emitting component 61 are arranged on the same inner wall of the mounting base body 4.
Embodiment III:
referring to fig. 7, the difference between the third embodiment of the present application and the second embodiment is that the magnetic grating 2 includes a plurality of groups of bar magnets 22 uniformly adhered to the end surface of the shaft disk 1 around the axis of the shaft disk 1, the connection direction of two poles of the bar magnets 22 is the same as the axis direction of the shaft disk 1, each group of bar magnets 22 can be provided with one bar magnet, and the magnetic poles of the adjacent two bar magnets 22 are opposite, so that after the two adjacent bar magnets 22 pass through the magnetic sensing component 5, the magnetic sensing component 5 outputs a half-period magnetic increment analog signal, one period range of the magnetic increment analog signal is a sine and cosine period range, that is, the value range of the magnetic increment analog signal of one period is 0-2 pi.
An absolute value encoder implementation principle of the third embodiment of the present application is different from that of the first and second embodiments: the arrangement of the bar magnet 22 is simpler and more convenient, and the cost of the bar magnet 22 is also relatively lower.
The above embodiments are not intended to limit the scope of the present application, so: all equivalent changes in structure, shape and principle of the application should be covered in the scope of protection of the application.
Claims (9)
1. An absolute value encoder, comprising:
A mounting base (4);
A hub (1) which rotates relative to the mounting base (4);
The magnetic grid (2) is arranged on the shaft disc (1) around the rotation axis of the shaft disc (1) and rotates along with the rotation of the shaft disc (1);
The magnetic sensing component (5) is arranged on the installation base body (4) corresponding to the magnetic grid (2), and the magnetic sensing component (5) performs magnetic sensing when the magnetic grid (2) rotates and obtains a magnetic increment analog signal;
a grating (3) which is arranged around the rotation axis of the shaft disk (1) on the shaft disk (1) and rotates along with the rotation of the shaft disk (1);
The optical sensing component (6) is arranged on the mounting base body (4) corresponding to the grating (3), and the optical sensing component (6) senses light and obtains an optical increment analog signal when the grating (3) rotates;
a signal processing unit (7) that receives and integrates the magnetic incremental analog signal and the optical incremental analog signal to obtain absolute position information;
The magnetic grating (2) circumferentially rotates along the magnetic grating to be sensed by a magnetic sensing component (5) for a circle, and N periods of magnetic increment analog signals are obtained; the grating (3) circumferentially rotates a circle of light sensing component (6) to sense and obtain light increment analog signals of M periods; n and M are integers and are mutually prime, M is greater than N, wherein N is greater than or equal to 2; the signal processing unit (7) is used for determining the period sequence number of the optical incremental analog signal by combining the optical incremental analog signal and the magnetic incremental analog signal so as to obtain absolute position information;
The signal processing unit (7) pre-stores the values psi n of the magnetic increment analog signals corresponding to the start points of all periods of the optical increment analog signals, wherein the psi n is uniformly distributed at equal intervals on all periods of the magnetic increment analog signals;
the signal processing unit (7) obtains a starting point of a period of the optical incremental analog signal and a value psi x of the magnetic incremental analog signal corresponding to the starting point through the optical incremental analog signal and the magnetic incremental analog signal acquired at any time, obtains a psi n equal to the psi x through comparison, namely, determines the period sequence number x of the optical incremental analog signal, the value range of the x is 1-M, and then obtains absolute position information;
the signal processing unit (7) is used for resolving the optical increment analog signal to obtain a digital angle theta 2, and an absolute position angle theta= (x-1) is 360 degrees/M+theta 2/M.
2. An absolute value encoder according to claim 1, wherein: the light sensing component (6) comprises a light emitting component (61) which is arranged on the mounting base body (4) and emits stable light towards the grating (3), and a light receiving component (62) which is arranged on the mounting base body (4) and receives light which periodically changes after passing through the grating (3) and outputs light increment analog signals.
3. An absolute value encoder according to claim 2, characterized in that: the grating (3) comprises a light-transmitting code disc (31) arranged on the shaft disc (1), a plurality of groups of photosensitive stripes (37) arranged on the light-transmitting code disc (31), at least one light-transmitting area (32) for transmitting light and at least one non-light-transmitting area (38) for preventing light from transmitting, wherein the light-transmitting areas (32) are arranged in M groups around the rotation axis of the light-transmitting code disc (31), the arrangement modes of the light-transmitting areas (32) are consistent, the similar side lines of the two adjacent groups of light-transmitting areas (32) coincide, and the light receiving assembly (62) and the light emitting assembly (61) are respectively arranged on two sides of the light-transmitting code disc (31) so that light emitted by the light emitting assembly (62) passes through the light-transmitting areas (32) and irradiates the light receiving assembly (62).
4. An absolute value encoder according to claim 3, characterized in that: the light-transmitting areas (32) are rectangular holes or trapezoid holes which are arranged along the radial direction of the light-transmitting code disc (31) in the length direction, the light-transmitting areas (32) are uniformly arranged around the rotation axis of the light-transmitting code disc (31), the central angles corresponding to the light-transmitting areas (32) and the non-light-transmitting areas (38) are equal, and the number of the light-transmitting areas (32) is M.
5. An absolute value encoder according to claim 2, characterized in that: the optical grating (3) comprises a reflection code disc (33) arranged on the shaft disc (1), light sense patterns (34) arranged on the reflection code disc (33) and used for reflecting light emitted by the light emitting component (61) to the light receiving component (62), M groups of the light sense patterns (34) are arranged around the rotation axis of the reflection code disc (33), the arrangement of each group of the light sense patterns (34) is consistent, the similar side lines of two adjacent groups of the light sense patterns (34) coincide, each group of the light sense patterns (34) comprises a high reflection coefficient region (35) and a low reflection coefficient region (36), and the intensity of reflected light received by the light receiving component (62) continuously and periodically changes from the high reflection coefficient region (35) to the low reflection coefficient region (36).
6. An absolute value encoder according to claim 1, wherein: the magnetic grid (2) is formed by splicing a plurality of concentric arc magnets (21), and the arrangement form of each arc magnet (21) is the same;
or the magnetic grid (2) is a magnet formed by magnetizing a whole multipole.
7. An absolute value encoder according to claim 1, wherein: the magnetic grid (2) is formed by uniformly distributing a plurality of strip magnets (22) around the rotation axis of the shaft disc (1), and the magnetic poles at the close ends of the two adjacent strip magnets (22) are different.
8. An absolute value encoder according to claim 1, wherein: the magnetic sensing component (5) comprises a magnetic induction device (51) for detecting magnetic field change, wherein the magnetic induction device (51) is any one of a magnetic induction chip, a Hall element, a magneto-resistance effect sensor and a giant magneto-resistance sensor.
9. A method for detecting the position of an absolute value encoder, characterized by: an absolute value encoder is provided, comprising a magnetic grating (2), a magnetic sensing component (5), a light sensing component (6), a grating (3) and a signal processing unit (7);
The magnetic sensing component (5) performs magnetic sensing and obtains magnetic increment analog signals when the magnetic grid (2) rotates relatively, and the magnetic grid (2) rotates along the circumferential direction for one circle, and the magnetic sensing component (5) senses and obtains N periods of magnetic increment analog signals;
The optical sensing component (6) senses light and obtains optical increment analog signals when the grating (3) rotates relatively, and the grating (3) rotates one circle of optical sensing component (6) along the circumferential direction to sense and obtain optical increment analog signals of M periods;
Wherein N and M are integers and are mutually equal, M is greater than N, and N is greater than or equal to 2;
The signal processing unit (7) combines the optical increment analog signal and the magnetic increment analog signal to determine the period sequence number x of the optical increment analog signal so as to obtain absolute position information;
The signal processing unit (7) pre-stores the value psi n of the incremental magnetic analog signal corresponding to the starting point of each period of the optical incremental analog signal, and the psi n is uniformly distributed at equal intervals on all periods of the magnetic incremental analog signal;
The signal processing unit (7) obtains a corresponding period starting point of the optical increment analog signal and a value ψx of the magnetic increment analog signal corresponding to the starting point through the optical increment analog signal and the magnetic increment analog signal acquired at any time, obtains a value ψn equal to the value ψx through comparison, namely, determines the period sequence number x of the optical increment analog signal, the value range of x is 1-M, and then obtains an absolute position signal;
The signal processing unit (7) is used for resolving the optical increment analog signal to obtain a digital angle theta 2;
Absolute position angle θ= (x-1) 360 degrees/m+θ 2/M;
The signal processing unit (7) is used for resolving the magnetic increment analog signal to obtain a digital angle theta 1;
The signal processing unit (7) is used for calculating the optical increment analog signal to obtain a digital angle theta 2;
The signal processing unit (7) pre-stores a group of theta 1 and theta 2 corresponding to each absolute position angle theta;
The signal processing unit (7) is used for calculating the magnetic increment analog signal acquired at the moment to obtain a data angle theta x and calculating the optical increment analog signal acquired at the moment to obtain a data angle theta y;
The signal processing unit (7) retrieves and outputs absolute positions corresponding to θ 1 and θ 2 which are the same as θ x and θ y.
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| JP2005172696A (en) * | 2003-12-12 | 2005-06-30 | Seiko Epson Corp | Absolute encoder |
| CN201438117U (en) * | 2009-05-04 | 2010-04-14 | 上海积致电子科技有限公司 | Coder |
| CN201471207U (en) * | 2009-08-20 | 2010-05-19 | 宁波海天精工机械有限公司 | Dual-direct-connection encoder detecting mechanism |
| JP5956207B2 (en) * | 2012-03-19 | 2016-07-27 | 山洋電気株式会社 | Encoder |
| CN107796419A (en) * | 2016-08-31 | 2018-03-13 | 青岛农业大学 | Low-cost and high-precision digital composite shaft angle detector |
| CN107941247A (en) * | 2017-12-18 | 2018-04-20 | 嘉兴市锐鹰传感技术有限公司 | A kind of passive wake-up formula encoder and method of work |
| CN108827352B (en) * | 2018-06-29 | 2021-08-27 | 广东工业大学 | Encoder and coded disc thereof |
| CN110864711B (en) * | 2018-08-27 | 2022-03-11 | 台达电子工业股份有限公司 | Encoder and position detection method thereof |
| CN110986746B (en) * | 2019-12-27 | 2020-09-22 | 上海舞肌科技有限公司 | Output side absolute position detection method, output side absolute position detection device, speed reduction motor and storage medium |
| CN111193357B (en) * | 2020-01-14 | 2022-06-28 | 连云港杰瑞电子有限公司 | Induction type absolute angle sensor |
| CN112880712A (en) * | 2021-01-18 | 2021-06-01 | 珠海格力电器股份有限公司 | Magneto-optical absolute encoder, and method and device for determining position of moving equipment |
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