Absolute value encoder with high decoding speed and method of operation thereof

Abstract

The application relates to an absolute value encoder with high decoding speed and a working method thereof. The absolute value encoder comprises an encoding disc provided with a plurality of independent and uniformly distributed code areas on a code track; the code area comprises an identification code and is located at the front end or the rear end of the code area. The absolute value encoder and the corresponding encoding and decoding method provided by the application have simple encoding mode, are easy to realize, reduce the manufacturing difficulty of the code disc, decode in the code area unit, greatly improve the decoding speed, and the use of adjustment code and check code improves the error correction capability, so that the whole decoding process is fast and accurate.

Description

Technical Field

[0001] This invention relates to an absolute encoder and its operating method. Background Technology

[0002] Rotary encoders are important sensors in industry for providing feedback on mechanical position, angle, length, and speed, and are involved in control. Based on the angle detection principle, they can be divided into optical, magnetic, inductive, and capacitive types. Based on their scaling method and signal output form, they can be divided into incremental encoders, absolute encoders, and absolute multi-turn encoders.

[0003] Incremental encoders calculate changes in relative position information, specifically the increase or decrease of a signal from one point to another. Also known as "relative," they require continuous counting by subsequent equipment. Since each data point is not independent but depends on previous readings, errors caused by power outages or interference cannot be assessed, leading to accumulated errors. In summary, the main issues are: 1. Power outage problems; 2. Signal interference resistance problems; 3. Resource utilization problems for subsequent equipment, especially for high-resolution encoders where continuous tracking and sampling by the subsequent equipment is required.

[0004] Based on the aforementioned shortcomings of incremental methods, people invented the "absolute working mode". This means that after the device is initialized, a zero point is determined. All subsequent position information is the absolute position relative to this "zero point". It does not require continuous counting by subsequent devices, but directly reads the current position value. As each reading is independent and unaffected by previous readings, it does not cause error accumulation. This is called the "absolute working mode" of the receiving device.

[0005] In fact, confusing the "absolute working mode" of the receiving device with the "absolute" of the absolute encoder is completely different from the "absolute encoding" of the absolute encoder. It may have counting errors and accumulation errors, power supply failure of the counting device, and failure to respond to counting at high speeds.

[0006] An absolute encoder, on the other hand, means that after the encoding is generated, all positions within its range are "absolutely" determined within the encoder. Each position is independent and unique. Each data read, both internally and externally, does not depend on the previous data read. There is no "counting" or accumulation of previous readings, whether inside or outside the encoder. Therefore, the true definition of an absolute encoder is the absolute correspondence between the encoded position and all positions within the range, an independent and unique absolute encoding that does not rely on the accumulation of internal or external counts.

[0007] In summary, for applications requiring high speed and security, it is best to use a true absolute encoder, where all positions are independent, unique, and absolute to ensure absolute data reliability and high-speed accuracy. Therefore, this invention presents an absolute encoding and decoding method with fast decoding speed and strong anti-interference capabilities. Summary of the Invention

[0008] The purpose of this invention is to provide an absolute encoder and its working method.

[0009] To solve the above-mentioned technical problems, the present invention provides an absolute encoder, comprising: an encoding disk having a plurality of independent and uniformly distributed code areas on a code track; the code areas include an identification code and are located at the front or rear end of the code area.

[0010] Furthermore, the identification code includes a single code or a combination of barcode sequences.

[0011] Furthermore, each of the code regions has the same length, which is suitable for mutual code recognition; and each code region is independent and unique, which is suitable for directly locating and identifying the current position.

[0012] Furthermore, the code area also includes a data code located behind the identification code, several check bits, and adjustment bits.

[0013] Furthermore, the data code is independent and unique, and suitable for directly locating the current position; and the data code consists of a continuous code of fixed length, or the data code is divided into two groups by a check code; wherein the check code is suitable for verifying part or all of the data code.

[0014] Furthermore, the adjustment bit is adapted to adjust the consistency of the light-transmitting or opaque properties of the identification code.

[0015] Furthermore, the check code is suitable for use in two's complement form.

[0016] In another aspect, the present invention also provides a method for operating an absolute encoder, including an encoding method and a decoding method.

[0017] Furthermore, the encoding method includes: The encoding disk is configured with several code zones sequentially according to a certain pattern, and the starting position of the first code zone is set; among them... The code area includes an identification code and a data code, with the identification code located at the front or back of the data code; The data code is divided into multiple sets of data codes by at least one check code or adjustment code, and the encoding conversion base corresponding to the binary in each set of data codes is determined. The data codes are then sequentially encoded on the encoding disk in consecutive cycles.

[0018] Furthermore, the decoding method includes: Locate all the identification codes in the image signal, convert the binary data in multiple sets of data codes in a code area into corresponding decimal numbers, and convert the corresponding decimal numbers into code area numbers through the corresponding encoding conversion base; The approximate angle of the code zone is obtained based on the code zone number and the code disk resolution; Then, based on the center position of the captured image, the length of the code area, and the positions of the identification code and the check code, the precise angle of the code area is determined.

[0019] The beneficial effects of this invention are that the absolute encoder and its corresponding encoding and decoding methods provided by this invention have simple encoding methods that are easy to implement, reducing the manufacturing difficulty of the code disk. Decoding is based on code areas, which greatly improves the decoding speed. The use of adjustment codes and check codes improves the error correction capability, making the entire decoding process fast and accurate. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a schematic diagram illustrating the working principle of the absolute encoder of the present invention; Figure 2(a) is a schematic diagram of the encoding method of the absolute encoder of the present invention, in units of code regions. Figure 1 ; Figure 2(b) is a schematic diagram of the encoding method of the absolute encoder of the present invention, with code regions as the unit; Figure 3 This is a schematic diagram of the encoding method of the absolute encoder of the present invention, using code regions as the unit. Figure 3 .

[0022] In the diagram, there is a light source 1, a code disk 2, a CCD 3, and lenses 41 and 42. Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0024] Example 1 like Figure 1 As shown, this embodiment provides an absolute encoder that is relatively simple to operate, has a small computational load, a fast measurement speed, low hardware cost, and strong anti-interference capability. It includes: an encoder disk that sequentially sets transparent codes and opaque codes according to a certain rule, and the transparent codes and opaque codes have multiple widths; wherein, a single code (or a combination of barcode sequences) with a fixed width is used as an identification code, and the space between two identification codes is a code area, each code area has an equal length, and the barcode combination method in each code area is unique.

[0025] The identification code can be located at the front end or the back end of the data code. In the embodiments of this application, the front end is used as an example.

[0026] In this embodiment, each code area is independent and unique, with the same length, and its width data bits (which can be simply referred to as width) can be limited to 20.

[0027] In this embodiment, the code area includes an identifier code, a data code, several check bits, and several adjustment bits, and has a lot of mutual information, which increases the error correction capability.

[0028] In this embodiment, the identification code can be a single code with a unique width or a combination of several specific code sequences, thereby improving the uniqueness of the identification code and reducing the difficulty of identification.

[0029] In this embodiment, the check bit is used to verify part or all of the data code, thereby improving error correction capability.

[0030] In this embodiment, the adjustment bit is used to adjust the consistency of the light transmission or opacity attribute of the identification code.

[0031] In this embodiment, adjacent code areas can help each other identify codes, improving error correction capabilities; and they can also identify codes across code areas, improving identification speed and efficiency.

[0032] In this embodiment, the check bit is in two's complement form to control the width of the data code and reduce the difficulty of reading the code.

[0033] Example 2 Based on Embodiment 1, Embodiment 2 also provides a working method for an absolute encoder, including an encoding method and a decoding method.

[0034] The encoding method includes: setting several code areas sequentially on the encoding disk according to a certain rule and setting the starting position of the first code area; wherein the code area includes an identifier code and a data code, the identifier code is located at the front or back of the data code; the data code is divided in the middle by at least one check code or adjustment code to obtain multiple sets of data codes, and the encoding conversion base corresponding to the binary in each set of data codes is determined, and the consecutive cycles are sequentially encoded on the encoding disk to achieve encoding.

[0035] In this embodiment, two groups are used as an example. The data code is divided into two groups by a check code. The encoding conversion base of the binary code in the first group is determined, and the encoding conversion base of the binary code in the second group is determined. The encoding is performed sequentially on the encoding disk for consecutive cycles to achieve encoding.

[0036] Specifically, as shown in Figures 2(a) and 2(b), the encoding method of an absolute encoder provided in this embodiment includes: the encoder disk is set with transparent codes and opaque codes in sequence according to a certain rule, and the transparent codes and opaque codes have multiple widths; wherein, a single code (or a combination of barcode sequences) with a fixed width is used as an identification code, and the area between two identification codes is a code area, each code area has the same length, and the barcode combination method in each code area is unique.

[0037] The width ratios of the translucent and opaque barcodes, after adjustment by the check and adjustment codes, are 1:2:3:6. The identification code is a combination of 1+6 light and dark barcodes. To control the width of the data code, it is divided into two groups with a check code in between. The widths of the two groups of data codes are 1+4 and 4 bits respectively. To control the width of the data bits, the binary encoding conversion base ranges corresponding to the data are selected as 2-14 and 1-14 respectively. The total width of the light and dark barcodes in each code area is 20. On a 360-degree encoding disk, the above method can produce 13×14=182 cycles, a total of 182 cycles. Here, 180 consecutive cycles are selected. If more refinement is needed, simply increase the number of bits in the data code combination (that is, increase the binary encoding conversion base range).

[0038] This decoding method includes: locating all the identifier codes in the image signal measured by the CCD; determining the current code region based on the center position of the image signal; calculating the actual position directly based on the data code combination of the current code region without signal matching; and determining the precise current position based on the center position of the identifier codes.

[0039] Specifically, the decoding method includes: locating all the identification codes in the image signal; converting the binary data in multiple sets of data codes in a code area into corresponding decimal numbers; converting the corresponding decimal numbers into code area numbers through corresponding encoding conversion bases; obtaining the approximate angle of the code area based on the code area number and the code disk resolution; and then determining the precise angle of the code area based on the center position of the image captured by the CCD, combined with the code area length, and the positions of the identification code and the check code.

[0040] by Figure 3 For example, a decoding method for an absolute encoder in this embodiment includes: from Figure 3See, the binary data bits of the first code area (left code area) are converted to decimal as 5 and 10 respectively; the binary data bits of the second code area (right code area) are converted to decimal as 10 and 4 respectively (and the two code areas are consecutive code areas, omitted here). Then, the corresponding decimal numbers are converted to code area numbers through the corresponding encoding conversion base. Here, a calculation formula is defined as (AX)×N+B=F, taking the code areas with data code decimal values ​​of 2 and 1 as the starting positions of all code areas. Then, the code area number can be calculated by the formula; where in this formula, A represents the decimal number corresponding to the first group of data codes, B represents the decimal number corresponding to the second group of data codes, X represents the decimal starting value corresponding to data code A, and B represents the value of the encoding conversion base. Figure 3 For example, the first code region is (5-2)×14 +10 = 52, and the second code region is (10-2)×14 +4 = 116. Since 180 cycles are selected, each cycle represents 2 degrees (resolution), so the approximate positions of the two code regions are 104 and 232 degrees. Then, based on the center position of the captured image, combined with the code region length of 20, and the positions of the identifier and check bits, the current relative precise positions can be derived. Finally, the calculated relative precise positions are combined to obtain the final result.

[0041] The encoding and decoding method of the absolute encoder of this invention features a simple, clear, and easy-to-implement encoding method, reducing the manufacturing difficulty of the code disk. During decoding, the use of a single code of a unique specific width or a combination of several specific code sequences significantly improves the accuracy of identification code recognition. Furthermore, the barcodes within each code area have only a fixed number of types and a certain proportional relationship with the identification code, which increases the efficiency of barcode recognition and reduces the probability of erroneous barcodes. Finally, since the combination of bright and dark barcodes in each code area is unique, the position on the code disk can be directly located by correctly identifying the barcode arrangement within the target area, eliminating the need for barcode matching. This greatly reduces the computational load when searching for target point positions, lowers chip CPU utilization, and improves measurement speed. Moreover, the use of check bits and adjustment bits significantly increases the barcode's error correction capability.

[0042] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for operating an absolute encoder, comprising an encoding method and a decoding method; The encoding method includes: The coding disk is set with transparent and opaque codes in sequence according to a certain pattern. The transparent and opaque codes have various widths. Among them, a combination of light and dark barcodes with a fixed total width is used as the identification code. The space between two identification codes is a code area. Each code area has an equal length, and the barcode combination method in each code area is unique. The width ratios of the translucent and opaque barcodes, after adjustment by the check and adjustment codes, are 1:2:3:

6. The identification code is a combination of light and dark barcodes with a width ratio of 1 and a width ratio of 6. To control the width of the data code, the data code is divided into two groups with a check code in between. The width data bits of the two groups of data codes are 1+4 and 4. "1+4" means that the first group of data codes consists of a barcode with a width ratio of 1 and a barcode with a width ratio of 4. The second "4" in "1+4, 4" means that the second group of data codes consists of a barcode with a width ratio of 4. The binary encoding conversion bases corresponding to the data to be selected are 2-14 and 1-14 respectively. The total width of the bright and dark barcodes in each code area is 20. On a 360-degree encoding disk, the above method can produce 13×14=182 cycles in total. The decoding method includes: converting the binary data bits of the first code area into decimal values ​​of 5 and 10; converting the binary data bits of the second code area into decimal values ​​of 10 and 4, with the two code areas being consecutive. Then, converting the corresponding decimal numbers into code area numbers using the corresponding encoding conversion base, defining the calculation formula (AX)×N+B=F, taking the code areas with decimal values ​​of 2 and 1 as the starting positions of all code areas, and calculating the code area numbers using the formula; where in this formula, A represents the decimal number corresponding to the first group of data codes, B represents the decimal number corresponding to the second group of data codes, X represents the decimal starting value corresponding to the first group of data codes, and N represents the value of the encoding conversion base corresponding to the second group of data codes, then the first code area (5-2)×14 +10 = 52, the second code area (10-2)×14 +4 = 116; Select 180 cycles, each cycle representing 2 degrees, to obtain the approximate positions of the two code areas at 104 and 232 degrees; Then, based on the center position of the captured image and the code area length of 20, as well as the positions of the identifier and check bits, deduce the current relative precise positions respectively, and then combine the calculated relative precise positions to obtain the final result.

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