CN109990811A - Encoder discs and rotary encoders - Google Patents

Abstract

The embodiment of the present invention discloses an encoder disk and a rotary encoder, wherein the rotary encoder includes a light source, an optical fiber encoder disk, an optical signal detector and a signal processor. The optical fiber encoder disk includes a plurality of optical fibers distributed in a circular array, and the outer side walls of adjacent fibers are close to each other; the light source and the optical signal detector are located at both ends of the optical fiber encoder disk along the length direction of the optical fiber; the optical fiber encoder disk and the optical signal detector Coaxial rotation at the same frequency; the signal processor is connected to the optical signal detector; the optical signal detector is used to collect the optical signal carrying the pulse fluctuation information emitted by the light source signal through each optical fiber during the rotation of the optical fiber encoder disk with the measured machine; signal processing The device is used to calculate the rotation angle of the machine under test according to the total number of pulse fluctuation information received during the rotation process of the machine under test. The present application not only realizes the miniaturization of the rotary encoder while ensuring the accuracy of the rotary encoder, but also reduces the difficulty of the manufacturing process and makes the signal processing circuit simpler.

Description

Encoder discs and rotary encoders

technical field

Embodiments of the present invention relate to the technical field of angular position measurement, and in particular, to an encoder disk and a rotary encoder.

Background technique

With the leap-forward progress of industrial control, the corresponding factory equipment such as robotic arms and large-stroke displacement measurement and control devices have more stringent requirements on rotating equipment. The angle position measurement of rotating equipment is very important in the entire industrial control field. The encoder is used as a servo drive system. The application of position measurement sensors is more and more extensive, and the accuracy of the rotary encoder determines the integrity of the industrial control system.

In the production and development process of rotary encoders, it is not only necessary to improve the measurement performance of rotary encoders, but also to control costs and focus on product economy. At present, the most used type of rotary encoder is the photoelectric encoder.

Photoelectric encoders mostly use the encoder disc as the encoder counting component, that is, many concentric distribution code tracks with unequal or equal grating pitches need to be engraved on the disc according to a certain coding method (each circle becomes a code track), and the circle Between the circle and the circle is a disc for measuring angular displacement arranged in a certain rule. The engraving precision of this kind of encoder disk is very high, the manufacturing process is complicated, and the manufacturing cost is relatively high, and multi-turn concentric distribution code tracks are often used to improve the resolution, so it is difficult to achieve miniaturization. In addition, the photoelectric encoder requires more receiving elements for receiving photoelectricity, which makes the circuit more complicated and the circuit is more difficult to process signals.

SUMMARY OF THE INVENTION

The embodiments of the present disclosure provide an encoder disk and a rotary encoder, which not only ensure the accuracy of the rotary encoder, but also realize the miniaturization of the rotary encoder, reduce the difficulty of the manufacturing process, and simplify the signal processing circuit.

In order to solve the above-mentioned technical problems, the embodiments of the present invention provide the following technical solutions:

One aspect of the embodiments of the present invention provides an encoder disk, which is applied to a rotary encoder, and includes a plurality of optical fibers distributed in a circular array, and the outer side walls of adjacent optical fibers are in close contact with each other.

Optionally, the specifications and models of each optical fiber are the same.

Another aspect of the embodiments of the present invention provides a rotary encoder, including a light source, an optical fiber encoder disk, an optical signal detector, and a signal processor;

Wherein, the optical fiber encoding disk includes a plurality of optical fibers distributed in a circular array, and the outer side walls of adjacent optical fibers are in close contact with each other; the optical fiber encoder disk and the optical signal detector are coaxially rotated at the same frequency; the signal processor is connected to the optical signal detector;

The optical signal detector is used to collect the optical signal carrying pulse fluctuation information emitted by the light source signal through each optical fiber during the rotation of the optical fiber encoder disk with the machine under test;

The signal processor is configured to calculate the rotation angle of the machine under test according to the total number of pulse fluctuation information received during the rotation of the machine under test.

Optionally, the optical fiber encoding disk includes a ring-shaped fixing bracket and a plurality of optical fibers;

The annular fixing bracket is fixed on the rotating shaft of the machine under test; the optical fibers are arranged on the outer sidewall of the section perpendicular to the axis of the annular fixing bracket, and the optical axis of each optical fiber is fixed to the annular fixing bracket. The axes of the brackets are parallel.

Optionally, the end face of each optical fiber in the optical fiber encoding disk is flush with the end face of the annular fixing bracket.

Optionally, the light emitting area of the light source is not larger than the cross-sectional area of each optical fiber of the optical fiber encoder disk.

Optionally, the signal processor calculates the rotation angle α of the machine under test according to the following formula:

In the formula, N is the total number of optical fibers contained in the optical fiber encoder disk, and m is the number of pulse fluctuation information.

Optionally, the signal processor is an FPGA board including a first conversion circuit and a second conversion circuit;

Wherein, the first conversion circuit is used to convert the optical signal into a corresponding digital pulse signal;

The second conversion circuit is used to count the variation of the digital pulse signal, and calculate the rotation angle of the machine under test according to the variation of the digital pulse signal.

Optionally, the FPGA board includes a wireless communication module, and the first conversion circuit and the second conversion circuit perform data transmission through the wireless communication module. Optionally, it also includes an angle value feedback module connected to the signal processor;

The angle value feedback module is used for sending the rotation angle calculated by the signal processor to the control system of the machine under test.

The advantage of the technical solution provided by the present application is that the encoder disk of the traditional encoder is replaced by a plurality of optical fiber structures in a circular array and closely arranged adjacent optical fibers. When the shaft to be measured rotates, the light-emitting light source passes through the corresponding optical fiber, so that the optical signal detector receives the optical signal of the monitored target, and then uses the signal processor to calculate the total number of pulse fluctuation information received during the rotation of the measured machine. Calculate its exact rotation angle value. Since the size of the optical fiber can be made small and the manufacturing process is less difficult, the size and manufacturing process difficulty of the entire encoder disk can be reduced, and the encoder can be miniaturized while ensuring the measurement accuracy of the rotary encoder; The realization circuit only needs to calculate the total number of pulse fluctuation information carried by the optical signal, and then the measured mechanical rotation angle can be calculated according to the total number and the total number of optical fibers. The signal processing circuit is easy to implement and has a simpler structure. In addition, the rotary encoder does not need to find a reference origin, and can measure the position any time it is powered back up after it has been powered down.

It is to be understood that the foregoing general description and the following detailed description are exemplary only and do not limit the present disclosure.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention or related technologies more clearly, the following briefly introduces the accompanying drawings that are used in the description of the embodiments or related technologies. Obviously, the drawings in the following description are only the present invention. For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

1 is a schematic structural diagram of an embodiment of an encoding disk provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a rotary encoder according to an embodiment of the present invention.

Detailed ways

In order to make those skilled in the art better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The terms "first", "second", "third", "fourth", etc. in the description and claims of the present application and the above drawings are used to distinguish different objects, rather than to describe a specific order. . Furthermore, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or elements is not limited to the listed steps or elements, but may include unlisted steps or elements.

After introducing the technical solutions of the embodiments of the present invention, various non-limiting implementations of the present application are described in detail below.

Referring first to FIG. 1, FIG. 1 is a schematic structural diagram of an encoder disk provided by an embodiment of the present invention under a specific implementation manner. As an encoder disk of a rotary encoder, an embodiment of the present invention may include the following contents:

The encoder disc is composed of a plurality of optical fibers 1 distributed in a circular array, and the outer side walls of adjacent optical fibers 1 are in close contact with each other. That is, every two adjacent optical fibers 1 have a common cut plane.

In order to facilitate subsequent signal processing and reduce the difficulty of signal processing, the types and specifications of the optical fibers 1 constituting the encoder disk can be the same, that is, the encoder disk is composed of multiple optical fibers with identical parameters and in contact with each other.

It can be understood that the encoder disk should rotate with the rotation of the machine under test, that is, the encoder disk should be fixed on the machine under test, and its axis of rotation coincides with the axis of the machine under test. In one embodiment, a plurality of optical fibers can be distributed on the outer side wall of the ring-shaped fixing bracket 0 in a one-layer annular array, that is, they are attached and closely arranged on the outer side wall of the section perpendicular to the central axis of the annular fixing bracket 1 . The optical axis of each optical fiber 1 is parallel to the axis of the annular fixing bracket 0 .

Optionally, in order to make the optical signal pass through the optical fiber completely and accurately, the end face of each optical fiber 1 can be set to be flush with the end face of the annular fixing bracket 0 .

In this embodiment, the annular fixing bracket 0 can be fixed on the rotating shaft of the machine under test, so as to realize fixing the encoder disk on the rotating shaft of the machine under test. The annular fixing bracket 0 can be made of any material, and the structural parameters of the annular fixing bracket 0, such as radial length, inner ring radius, outer ring radius and other parameters can be set according to specific application scenarios and user needs. As the outer diameter of the fixing bracket of the optical fiber bundle increases, the resolution of the encoder will also increase accordingly. In the case that the outer diameter of the annular fixing bracket 0 is constant, the inner diameter of the annular fixing bracket 0 can be customized to achieve different sizes. 's shaft. That is to say, the outer diameter of the annular fixing bracket 0 can be determined according to the resolution required by the user, and then the inner diameter of the annular fixing bracket 0 can be determined according to the size of the rotating shaft of the machine under test, and finally according to the user's weight requirements for the encoder disk, production costs and various The cost of the optical fiber determines the material of the annular fixing bracket 0 .

It should be noted that all the optical fibers in this embodiment are attached to the ring-shaped fixing bracket 0 , and the "ring-shaped array distribution" specifically refers to that after all the optical fibers 1 The cross-section of the fixing bracket 0 in the direction perpendicular to the axis includes circular (or elliptical, or quasi-circular) cross-sections of a plurality of optical fibers distributed annularly with the center of the cross-section of the annular fixing bracket 0 as the center, and the cross-section of any optical fiber is It is in contact with the cross-sections of two adjacent optical fibers, as shown in Figure 1. In addition, each optical fiber 1 is parallel to the axis of the annular fixing bracket 0 .

In the technical solution provided by the embodiment of the present invention, the encoder disk of the traditional encoder is replaced by a plurality of optical fiber structures in a circular array and the adjacent optical fibers are closely arranged. Since the size of the optical fibers can be made small and the manufacturing process is less difficult, Therefore, the size and manufacturing process difficulty of the entire encoder disc can be reduced, and the miniaturization of the encoder can be realized while ensuring the measurement accuracy of the rotary encoder.

In addition, the present application also provides a rotary encoder. Please refer to FIG. 2 . FIG. 2 is a schematic structural diagram of a rotary encoder provided by an embodiment of the present invention in a specific implementation manner. An embodiment of the present invention may include the following contents:

A rotary encoder may include a light source 21 , an optical fiber encoder disk 22 , an optical signal detector 23 and a signal processor 24 .

Wherein, the light source 21 and the optical signal detector 23 are located at both ends of the optical fiber encoder disk 22 along the length direction of the optical fiber; the optical fiber encoder disk 22 and the optical signal detector 23 rotate coaxially at the same frequency; the signal processor 24 is connected to the optical signal detector 23 .

In this embodiment, the optical fiber encoder disk 22 may include a plurality of optical fibers distributed in a circular array, and the outer sidewalls of adjacent optical fibers are in close contact with each other. In one embodiment, the optical fiber encoder disc 22 may include a ring-shaped fixing bracket 0 and a plurality of optical fibers 1; The optical fibers 1 are closely arranged on the wall, and the optical axis of each optical fiber 1 is parallel to the axis of the annular fixing bracket. The functions of the optical fiber encoder disc 22 according to the embodiment of the present invention can be implemented according to the specific implementation of each functional module of the encoder disc in the above-mentioned embodiment, and the specific implementation process can refer to the relevant description of any one of the above-mentioned embodiments, which will not be repeated here.

It should be noted that the light emitted from the light source 21 enters the optical fiber aligned with it, and then emits an optical signal carrying pulse fluctuation information after being transmitted by the optical fiber. The number of pieces calculates the rotation angle of the machine under test, that is to say, the statistical accuracy of the total number of pulse fluctuation information determines the calculation accuracy of the final rotation angle. Therefore, the light-emitting area of the light source is not larger than the cross-sectional area of each optical fiber of the optical fiber encoder disk. That is, the light signal emitted by the light source can only enter the optical fiber aligned with it, and will not enter the adjacent optical fiber.

It can be understood that the optical signal detector 23 can be used to collect the optical signal carrying pulse fluctuation information emitted by the light source signal through each optical fiber when the optical fiber encoder disc 22 rotates with the machine under test.

Optionally, the optical signal detector 23 and the light source 21 can be fixed on both ends of the fixed annular fixing bracket 0 of the optical encoder disk 22 through a clamp, and the optical fiber encoder disk 22 and the optical signal detector 23 rotate with the rotation of the measured machine. Rotation, the rotation angle of the optical signal detector 23 is the rotation angle of the mechanical shaft to be measured.

The signal processor 24 can be used to calculate the rotation angle of the machine under test according to the total number of pulse fluctuation information received during the rotation process of the machine under test.

In order to improve the data processing operation speed and simplify the complexity of the signal processing circuit, the signal processor 24 may adopt an FPGA board supporting parallel computing, and the FPGA board may include a first conversion circuit and a second conversion circuit.

Wherein, the first conversion circuit is used to convert the optical signal into a corresponding digital pulse signal; the second conversion circuit is used to count the variation of the digital pulse signal, and calculate the measured mechanical Rotation angle. In this embodiment, by calculating the variation of the pulse signal and converting it into the rotation angle of the rotating shaft of the machine under test, the rotary encoder does not need to search for the reference origin, and the position can be directly measured when the power is turned off again.

It can be seen from the above that in the embodiment of the present invention, the encoder disk of the traditional encoder is replaced by a plurality of optical fibers in a circular array and the adjacent optical fibers are closely arranged. When the shaft to be measured rotates, the light-emitting light source passes through the corresponding optical fiber, so that the optical signal detector receives the optical signal of the monitored target, and then uses the signal processor to calculate the total number of pulse fluctuation information received during the rotation of the measured machine. Calculate its exact rotation angle value. Since the size of the optical fiber can be made small and the manufacturing process is less difficult, the size and manufacturing process difficulty of the entire encoder disk can be reduced, and the encoder can be miniaturized while ensuring the measurement accuracy of the rotary encoder; The realization circuit only needs to calculate the total number of pulse fluctuation information carried by the optical signal, and then the measured mechanical rotation angle can be calculated according to the total number and the total number of optical fibers. The signal processing circuit is easy to implement and has a simpler structure. In addition, the rotary encoder does not need to find a reference origin, and can measure the position any time it is powered back up after it has been powered down.

In a specific embodiment, the signal processor 24 can calculate the rotation angle α of the machine under test according to the following formula:

In the formula, N is the total number of optical fibers contained in the optical fiber encoder disk, m is the number of pulse fluctuation information, and m%N is the remainder.

Specifically, the optical fiber encoder disc 22 has N optical fibers, the optical signal detectors distributed along the circumferential direction rotate with the rotation of the rotating shaft, and the optical signal of the light-emitting light source passing through each optical fiber will have pulses when each optical fiber rotates Fluctuation, the pulse fluctuation information of the optical signal is received by the optical signal detector and transmitted to the FPGA processing circuit. The FPGA processing circuit converts the optical signal received by the optical signal detector into a digital pulse signal through the first conversion circuit, and then sends the digital pulse signal to the second processing circuit, counts the variation of the pulse signal and calculates the conversion into The angle of rotation of the shaft under test. Finally, the detection of the angular position of the rotating shaft is realized. For example, when the rotary encoder has turned m optical fibers, the optical signal detector will detect the pulse fluctuation information of m optical signals, and through the first and second conversion circuits, count the rotation number m at this time, and according to Formula (1) converts the exact rotation angle value.

Optionally, the FPGA board may further include a wireless communication module, and the first conversion circuit and the second conversion circuit perform data transmission through the wireless communication module. Of course, the first conversion circuit and the second conversion circuit can also be transmitted by wire, which does not affect the implementation of the present application.

In a specific embodiment, the rotary encoder may further include an angle value feedback module connected with the signal processor 23 . The angle value feedback module is used for sending the rotation angle calculated by the signal processor 22 to the control system of the machine under test. That is to say, the signal processor 3 can also output the actual angular position of the rotating shaft to the control system of the measured motor for feedback processing after calculating and converting it into the rotation angle of the rotating shaft of the measured machine according to the variation of the pulse signal obtained by statistics. Accurately control the rotational position and speed of the shaft.

In order to verify that this application can improve the measurement accuracy of the rotary encoder, this application can select a single-mode optical fiber with a core diameter of 8 μm and a cladding diameter of 125 μm to form an optical fiber code disc. The outer diameter of the ring-shaped fixing bracket can be 150 mm. The number of optical fibers distributed around the circumference is 150mm*3.1415926/125μm=3768. Therefore, the resolution of the encoder is at least 360/(3768)=343", and the unit of angle is arc second. Further, as the outer diameter of the fixing bracket of the fiber bundle increases, the resolution of the encoder will also correspond improve.

The absolute encoder in the related art generally has a resolution of 11 bits, which is 360/(2^11)=632" (angle unit: arc second). It can be seen from this that the rotary encoder of the present application and the rotation of the related art Compared with the encoder, the resolution can be greatly improved, which greatly reduces the manufacturing cost.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments may be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

Professionals may further realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two, in order to clearly illustrate the possibilities of hardware and software. Interchangeability, the above description has generally described the components and steps of each example in terms of functionality. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of the present invention.

The steps of a method or algorithm described in conjunction with the embodiments disclosed herein may be directly implemented in hardware, a software module executed by a processor, or a combination of the two. A software module can be placed in random access memory (RAM), internal memory, read only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other in the technical field. in any other known form of storage medium.

The rotary encoder provided by the present invention has been described in detail above. The principles and implementations of the present invention are described herein by using specific examples, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (10)

1. a kind of coding disk, which is characterized in that it is applied to rotary encoder, the optical fiber including the distribution of a plurality of circular array, and The lateral wall of adjacent fiber is mutually close to.

2. coding disk according to claim 2, which is characterized in that specification, the model of each optical fiber are all the same.

3. a kind of rotary encoder, which is characterized in that including light source, optical fiber code disk, optical signal detector and signal processor；

Wherein, the optical fiber code disk includes the optical fiber of a plurality of circular array distribution, and the lateral wall of adjacent fiber is mutually close to； The light source and the optical signal detector are located at the both ends that the optical fiber code disk prolongs fiber length；The optical fiber code Disk is coaxial with frequency rotation with the optical signal detector；The signal processor is connected with the optical signal detector；

The optical signal detector is for acquiring the optical fiber code disk with light signal described in tested mechanical rotation process Pass through the optical signal of the carrying pulse ripple information of each fiber exit；

The signal processor is based on according to the pulse ripple information total number received in the tested mechanical rotation process Calculate the rotational angle of the tested machinery.

4. rotary encoder according to claim 3, which is characterized in that the optical fiber code disk includes cyclic annular fixed bracket With a plurality of optical fiber；

The fixed bracket of annular is fixed in the shaft of the tested machinery；Perpendicular to the cyclic annular fixed bracket axis Fitting arranges each optical fiber on the lateral wall in section, and the optical axis of each optical fiber is parallel with the cyclic annular fixed bracket axis.

5. rotary encoder according to claim 4, which is characterized in that the end face of each optical fiber in the optical fiber code disk With the support bracket fastened end face flush of the annular.

6. according to rotary encoder described in claim 3-5 any one, which is characterized in that the light-emitting area of the light source is not Greater than the area of section of each optical fiber of the optical fiber code disk.

7. according to rotary encoder described in claim 3-5 any one, which is characterized in that the signal processor is under State the rotational angle α that formula calculates the tested machinery:

In formula, N is the total number that the optical fiber code disk includes optical fiber, and m is the number of pulse ripple information.

8. according to rotary encoder described in claim 3-5 any one, which is characterized in that the signal processor is to include The FPGA board of first conversion circuit and the second conversion circuit；

Wherein, first conversion circuit is used to convert corresponding digital pulse signal for the optical signal；

Second conversion circuit is used for the variable quantity of statistics pulse signal, and according to the variation of the digital pulse signal Amount calculates the rotational angle of the tested machinery.

9. rotary encoder according to claim 8, which is characterized in that the FPGA board includes wireless communication module, First conversion circuit and second conversion circuit are carried out data transmission by the wireless communication module.

10. rotary encoder according to claim 9, which is characterized in that further include being connected with the signal processor Angle value feedback module；

The angle value feedback module is used to the rotational angle that the signal processor is calculated being sent to the tested machine The control system of tool.