A phase difference-based non-hollow encoder and encoding method

Abstract

The application provides a phase difference based non-hollow encoder and an encoding method, an encoder code disc is averagely divided into N baffle sectors and N-1 or N+1 infrared receiving lamp sectors; one baffle is arranged in each of the N-1 or N+1 baffle sectors, and the other baffle sector is an empty sector; a plurality of infrared receiving lamps are sequentially arranged along the outer periphery of the arc of any infrared receiving lamp sector, an infrared emitting lamp is arranged at the position of the rotating shaft of the encoder code disc corresponding to any infrared receiving lamp sector; the baffle is located between the infrared receiving lamp and the infrared emitting lamp; the method combining the infrared emitting lamp, the infrared receiving lamp and the baffle has the advantages of simple structure, low preparation cost and easy maintenance. The encoder code disc is averagely divided into N baffle sectors and N-1 or N+1 infrared receiving lamp sectors, so that high-precision positioning and detection can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of encoder design, in particular to a non-hollow encoder based on phase difference and an encoding method. BACKGROUND

[0002] As a mainstream form of optical encoder, the glass code disc is positioned by identifying the track on the glass code disc through laser light, and has high precision and stability. However, the track (also known as grating or two-dimensional code) on the code disc needs to be prepared by precise machining technology, including photoetching, etching, coating and polishing, etc. These processes require to be carried out in a dust-free room environment to ensure that the size and surface quality of the track meet the high-precision requirements. Therefore, the manufacturing process of the code disc is complex, the manufacturing cost is relatively high, and the code disc is made of glass material, which is easy to damage and has high maintenance cost. SUMMARY

[0003] The present application relates to the technical field of encoder design, in particular to a non-hollow encoder based on phase difference and an encoding method.

[0004] The present application provides a non-hollow encoder based on phase difference, comprising: N sector, N-1 or N+1 infrared receiving lamp sector, sector, infrared receiving lamp group and infrared emitting lamp.

[0005] The encoder disc is evenly divided into N sector and N-1 or N+1 infrared receiving lamp sector.

[0006] N-1 sector is provided with a sector, and the Nth sector is an empty sector.

[0007] The infrared receiving lamp group is provided along the outer periphery of any infrared receiving lamp sector; the infrared receiving lamp group is provided with a plurality of infrared receiving lamps arranged at equal intervals.

[0008] Any infrared receiving lamp sector corresponds to the position of the rotating shaft of the encoder disc, and an infrared emitting lamp is arranged at the position; the sector is located between the infrared receiving lamp and the infrared emitting lamp.

[0009] Further, one end of the sector is located inside the sector, and the other end is located on the edge of the sector.

[0010] Further, the distance between any two sectors is greater than the width of the light emitted by the infrared emitting lamp.

[0011] Further, the arc length of the sector is less than or equal to half of the arc length of the sector.

[0012] Further, the number of infrared receiving lamps in any of the infrared receiving lamp sectors is greater than or equal to 3.

[0013] Further, the angle difference between one of the infrared receiving lamps and another of the infrared receiving lamps in any of the infrared receiving lamp groups is 360 / (N-1)°-360 / N° or 360 / N-360 / (N+1)°.

[0014] Further, a virtual infrared lamp is provided between any two of the infrared receiving lamps.

[0015] Further, the virtual infrared lamp is provided by at least one algorithm tool including analog software, algorithm library, and embedded system.

[0016] Further, the minimum angle change size that can be distinguished by the encoder is (360 / N-360 / (N-1)°) / w or (360 / N-360 / (N+1)°) / w.

[0017] wherein w is the change range of each of the virtual infrared lamps on the analog signal.

[0018] The application also provides an encoding method of the non-hollow encoder based on phase difference, which adopts the non-hollow encoder based on phase difference.

[0019] Compared with the prior art, the application has at least the following technical effects:

[0020] The application combines the infrared emitting lamp, the infrared receiving lamp, and the baffle, has simple structure, low preparation cost, and is easy to maintain, further, by dividing the encoder code disc into N baffle sectors and N-1 infrared receiving lamp sectors, high-precision positioning and detection can be realized, the N-1 infrared receiving lamp sectors provide the transition between adjacent baffle sectors, which helps to reduce errors and improve reading stability.

[0021] Further, the application combines the virtual infrared lamp, which can realize more uniform and dense position detection coverage without increasing the number of actual receiving lamps, thereby improving the reliability and stability of the system, obtaining more fine position detection, and not needing to arrange the receiving lamps more densely in physics, thereby saving the cost. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 FIG. 1 is a structural schematic diagram of the non-hollow encoder based on phase difference in an embodiment of the application;

[0023] Figure 2 FIG. 2 is another structural schematic diagram of the non-hollow encoder based on phase difference in an embodiment of the application. DETAILED DESCRIPTION

[0024] The application will now be described by way of example with reference to the accompanying drawings in which:

[0025] The application will now be described by way of example with reference to the accompanying drawings in which:

[0026] The application will now be described by way of example with reference to the accompanying drawings in which:

[0027] The encoder disc is evenly divided into N sectors and N-1 or N+1 infrared receiving lamp sectors.

[0028] N-1 sectors are provided with a baffle respectively, and the Nth sector is an empty sector; the infrared receiving lamp group is arranged along the outer periphery of the infrared receiving lamp sector; the infrared receiving lamp group is provided with a plurality of infrared receiving lamps arranged at equal intervals; the infrared emitting lamp is arranged at the position of the rotating shaft of the encoder disc corresponding to any infrared receiving lamp sector; and the baffle is located between the infrared receiving lamp and the infrared emitting lamp.

[0029] The application provides an encoder with simple structure, low cost and easy maintenance, and further realizes high-precision positioning and detection by evenly dividing the encoder disc into N sectors and N-1 or N+1 infrared receiving lamp sectors.

[0030] Further, the working principle of the encoder disclosed in the embodiment is as follows: when the code disc rotates, the infrared emitter continuously emits infrared light, and the blocking piece alternately blocks and exposes the light source, so that the light intensity detected by the infrared receiving lamp changes, thereby generating high pulse signals and low pulse signals (when the blocking piece blocks the light source that can be received by the infrared receiving lamp, a low pulse signal is generated, and when the blocking piece moves away, a high pulse signal is generated), and the pulse signals are processed by using a high-precision signal processing algorithm to determine the time interval between the blocking piece passing through any infrared receiving lamp sector and the two adjacent infrared receiving lamps, thereby calculating the rotating speed of the code disc. In combination with the rotating speed of the code disc and the time interval passed by the blocking piece, the angle of rotation of the code disc can be calculated.

[0031] In the embodiment, the number of infrared receiving lamp sectors and blocking piece sectors has a direct impact on the resolution and accuracy of the encoder. In theory, the more the number of the two kinds of sectors, the higher the resolution, however, too many sectors will increase the complexity of the system, affecting the accuracy and stability of the code disc. In addition, too many sectors may increase the manufacturing cost, therefore, in the actual preparation process, the appropriate number of sectors needs to be selected according to the actual demand.

[0032] In a specific embodiment, the number of blocking piece sectors is 16, and the number of infrared receiving lamp sectors is 15, or 17.

[0033] In another specific embodiment, the number of blocking piece sectors is 14, and the number of infrared receiving lamp sectors is 16.

[0034] In the embodiment, one of the infrared receiving lamps in the infrared receiving lamp group is arranged close to the edge of the sector, and the remaining infrared receiving lamps are arranged close to each other in turn, and the two infrared receiving lamps are equidistantly arranged. The different infrared receiving lamp groups are also equidistantly arranged. The uniform and equidistant arrangement of the infrared receiving lamp groups, especially the arrangement of one receiving lamp close to the edge of the sector, provides an accurate starting reference point, thereby improving the resolution, reliability and robustness of the system, and simplifying the calibration process.

[0035] In the embodiment, the infrared receiving lamp is a photodiode. Those skilled in the art can select different types of infrared receiving lamps according to actual conditions.

[0036] Further, the specific number of infrared receiving lamps also has a direct impact on the resolution and accuracy of the encoder. In theory, increasing the number of infrared receiving lamps can improve measurement accuracy, as more infrared receiving lamps can provide more detailed angular resolution, allowing the encoder to detect smaller position changes. Multiple infrared receiving lamps can also provide more light sources for detection, improving the uniformity and intensity of system illumination. However, too many infrared receiving lamps can result in a dense arrangement of infrared receiving lamps, affecting signal reception. In addition, too many infrared receiving lamps can also increase design costs. Therefore, during actual production, the appropriate number of infrared receiving lamps needs to be selected based on factors such as sector size and production cost.

[0037] In one embodiment, three infrared receiving lamps are provided in one infrared receiving lamp group.

[0038] The role of the shutter in the code disc is to modulate the light beam emitted by the infrared emitting lamp. By setting the shutter in the light beam path, a specific light pulse pattern can be created.

[0039] In this embodiment, one end of the shutter is located inside the shutter sector, and the other end is located on the edge of the shutter sector. The specific arc length of the shutter should match the arc length of the code disc sector, that is, the longer the arc length of the code disc sector, the longer the specific arc length of the shutter, or the arc length of the code disc sector is proportional to the arc length of the shutter, to improve the accuracy and resolution of the code disc. However, the shutter should not be too large, as a large shutter may cause the infrared receiving lamps of adjacent sectors to detect the shutter at the same time, thereby reducing accuracy.

[0040] In one specific example, the arc length of the shutter is less than or equal to one-half of the arc length of any of the shutter sectors and greater than one-third of the arc length. For example, assuming there are 16 shutter sectors, after determining the radius of the shutter sector, the angle of each shutter sector is 22.5° (this angle refers to the angle between the two radii of the sector and the center point of the code disc is 22.5°), the angle range of each shutter can also be set to 7.5°-12.25° (this angle range refers to the angle between the two ends of the shutter arc and the center point of the code disc is 7.5°-12.25°), and the arc length of the shutter is set according to the angle of the shutter and the radius of the shutter sector.

[0041] In addition, the arc lengths of all shutters in the code disc are generally set to be equal, so that each shutter modulates the light beam uniformly, which helps to generate consistent and predictable pulse signals. Further, the spacing distance between each pair of shutters needs to be greater than the width of the light emitted by the infrared emitting lamp. If the spacing between the shutters is less than the width of the light beam of the infrared emitting lamp, the light beam may overlap between adjacent shutters, causing the signal received at the receiving end to be unclear, affecting the accuracy and resolution of the signal.

[0042] Further, in the embodiment, the infrared emitting lamps are arranged around the position of the code disc rotating shaft to emit infrared light.

[0043] In the embodiment, the number of the infrared emitting lamps is equal to the number of the infrared lamp receiving sectors, one infrared receiving lamp is arranged in one infrared lamp receiving sector, so that each infrared receiving lamp area on the code disc can receive infrared light, thereby improving the reading accuracy.

[0044] In a specific embodiment, the number of the infrared lamp receiving sectors is 16, and the number of the infrared emitting lamps is also 16.

[0045] Further, in the embodiment, the distance between two infrared emitting lamps is equal, and the distance between the infrared emitting lamps refers to the center distance between two infrared emitting lamps.

[0046] In addition, an empty sector is also arranged in the embodiment, due to the existence of the empty sector, by monitoring the scanning signals (the scanning signals are the changes of the light intensity detected by the receiving lamp when the shutter blocks and exposes the infrared light source) generated by the infrared emitting lamps and the infrared receiving lamps in a circle (i.e. a complete rotation period), the position of the shutter adjacent to the position of the empty sector can be roughly identified, so as to improve the accuracy and reliability of the angle measurement.

[0047] By using the existence of the empty sector and the scanning signals between the infrared emitting and receiving, the position of the shutter can be effectively identified, and the measurement accuracy of the code disc rotating angle can be improved.

[0048] In the embodiment, since the number of infrared receiving lamp sectors on the code disc is one more than the number of the sectors of the baffle, there is an angle difference x° between the two adjacent infrared lamps or between any infrared receiving lamp sector and the sector of the baffle adjacent thereto, the size of the angle difference x° is 360 / N-360 / (N+1)° or 360 / (N-1)°-360 / N°, that is, the angle difference between one of the infrared receiving lamps in any infrared receiving lamp group and the other infrared receiving lamp is 360 / (N-1)°-360 / N° or 360 / N-360 / (N+1)°. Due to the limitation of the actual physical space, more infrared lamps cannot be placed in the actual device to improve the resolution, therefore, the angle difference x° can be used to virtually increase the number of infrared receiving lamps, specifically, a virtual infrared receiving lamp is virtually placed at a position every x° around each infrared lamp, for example, an actual infrared receiving lamp is arranged at any position outside the sector arc of the infrared receiving lamp, and a virtual infrared receiving lamp is placed at a position x° to the left of the infrared receiving lamp, and a virtual infrared receiving lamp is also placed at a position x° to the right of the infrared receiving lamp. In this way, two virtual infrared receiving lamps are placed around each actual infrared receiving lamp. It can be understood that the virtual receiving infrared lamp can be a set of virtual positions obtained by calculation method (that is, positions x° away from the actual infrared receiving lamp). These virtual positions simulate the function of the actual infrared receiving lamp, and measurement or detection can be performed at these positions.

[0049] In a specific embodiment, when the sector of the baffle is 16 and the sector of the infrared receiving lamp is 15, the angle difference between one of the infrared receiving lamps in any infrared receiving lamp group and the other infrared receiving lamp is 1.5°, then a virtual receiving infrared lamp is arranged at a position of 1.5°.

[0050] The virtual infrared receiving lamp is generated by an algorithm tool, which includes but is not limited to simulation software, algorithm library and embedded system.

[0051] Further, if the AD signal (analog-to-digital converter output signal) variation range of each infrared receiving lamp in the x° range is w (the resolution of ADC, that is, the minimum voltage change that can be distinguished by the ADC), then the theoretical design accuracy is x° / w (the design accuracy refers to the closeness between the position measurement value and the true value of the position), if the AD signal variation range w is smaller, then the theoretical accuracy is higher. That is, the angle corresponding to each AD signal variation unit. For example, if the AD signal variation range of each infrared lamp in the x° range is 1 mV, and x° is 1°, then the theoretical design accuracy is 1° / mv.

[0052] By virtually combining infrared lamps, more uniform and denser position detection coverage can be achieved without increasing the number of actual receiving lamps, thereby improving the reliability and stability of the system and obtaining more precise position detection, without the need for overly dense arrangement of actual infrared receiving lamps, thereby saving costs.

[0053] Please refer to Figure 1 , the following will be introduced as an example of the possible specific structure of the encoder: N = 16, any of the infrared receiving lamp sectors is arranged with 3 infrared receiving lamps in sequence on the outer periphery of the arc, and any of the infrared receiving lamp sectors is provided with 1 infrared emitting lamp at the position of the code disc rotating shaft.

[0054] The number of baffle sectors is 16, and each sector is 22.5° wide; the number of infrared receiving lamp sectors is 15, and each sector is 24° wide. Among the 16 baffle sectors, 15 sectors are provided with a baffle with an arc length of 11.25°, which is half of the arc length of the baffle. Every 6° in each infrared receiving lamp sector (the angle difference between the centers of two infrared receiving lamps is 6°) is arranged with an infrared receiving lamp. The outer periphery of each infrared receiving lamp sector is arranged with 3 infrared receiving lamps in sequence, and any of the infrared receiving lamp sectors is provided with 1 infrared emitting lamp at the position of the code disc rotating shaft. There is an angle difference of 1.5° between any two adjacent infrared receiving lamps or any infrared receiving lamp sector and the baffle sector adjacent thereto. Assuming that the 8-bit 255 range of the intensity change of 1.5° of each infrared lamp region passed by the baffle is 8, then the accuracy of the final scheme is 1.5° / 255, which is approximately equal to 0.0059°.

[0055] Please refer to Figure 2 , the following will be introduced as an example of the possible specific structure of the encoder: N = 14, any of the infrared receiving lamp sectors is arranged with 3 infrared receiving lamps in sequence on the outer periphery of the arc, and any of the infrared receiving lamp sectors is provided with 1 infrared emitting lamp at the position of the code disc rotating shaft.

[0056] The number of the baffle sectors is 14, each sector is 25.714° wide; the number of the infrared receiving lamp sectors is 15, each sector is 24° wide, 13 sectors of the 14 baffle sectors are provided with a baffle with an arc length of 12.875°, which is half of the arc length of the baffle, every 6° (the angle difference between the midpoints of two infrared receiving lamps is 6°) in each infrared receiving lamp sector is arranged with an infrared receiving lamp, the outer periphery of each infrared receiving lamp sector is sequentially arranged with 3 infrared receiving lamps, the infrared emitting lamp corresponding to any infrared receiving lamp sector is arranged at the position of the code disc rotating shaft, the angle difference between two adjacent infrared receiving lamps or any infrared receiving lamp sector and the adjacent baffle sector is 1.714°, assuming that the 1.714° intensity change range of each infrared lamp region is 8 bits 255, then the accuracy of the final scheme is 1.714° / 255, which is about 0.0067°.

[0057] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A non-hollow encoder based on phase difference, characterized in that, include: N baffle sectors, N-1 or N+1 infrared receiving lamp sectors, baffles, infrared receiving lamp groups and infrared emitting lamps; The encoder disk is divided into N baffle sectors and N-1 or N+1 infrared receiving lamp sectors. Each of the N-1 baffle sectors is provided with a baffle, and the Nth baffle sector is an empty sector; An infrared receiving lamp group is provided along the outer periphery of the arc of any of the infrared receiving lamp sectors; the infrared receiving lamp group is provided with multiple infrared receiving lamps arranged at equal intervals; An infrared emitting lamp is provided at the rotation shaft position of the encoder disk corresponding to any of the infrared receiving lamp sectors; the baffle is located between the infrared receiving lamp and the infrared emitting lamp.

2. The phase difference-based non-hollow encoder as described in claim 1, characterized in that, One end of the baffle is located inside the baffle sector, and the other end is located on the edge of the baffle sector.

3. The phase difference-based non-hollow encoder as described in claim 2, characterized in that, The distance between any two of the baffles is greater than the width of the light emitted by the infrared emitting lamp.

4. The phase difference-based non-hollow encoder as described in claim 3, characterized in that, The arc length of the baffle is less than or equal to one-half of the arc length of the baffle sector.

5. The phase difference-based non-hollow encoder as described in claim 1, characterized in that, The number of infrared receiving lamps set in any of the infrared receiving lamp sectors is greater than or equal to 3.

6. The phase difference-based non-hollow encoder as described in claim 1, characterized in that, The angular difference between one infrared receiving lamp and the other infrared receiving lamp in any infrared receiving lamp group is 360 / (N-1)°-360 / N° or 360 / N-360 / (N+1)°.

7. The phase difference-based non-hollow encoder as described in claim 1, characterized in that, A virtual infrared light is placed between each pair of infrared receiving lights.

8. The phase difference-based non-hollow encoder as described in claim 7, characterized in that, The virtual infrared light is configured using at least one algorithm tool, including simulation software, algorithm libraries, and embedded systems.

9. The phase difference-based non-hollow encoder as described in claim 8, characterized in that, The encoder can distinguish the smallest angle change size as (360 / N-360 / (N-1)°) / w, or (360 / N-360 / (N+1)°) / w; Where w is the range of variation of each virtual infrared lamp in the analog-to-digital signal.

10. An encoding method for a non-hollow encoder based on phase difference, characterized in that, The non-hollow encoder based on phase difference is used as described in any one of claims 1-9.

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