Grating code disc capable of realizing directional zero searching and incremental encoder
By adding a zero-finding code track to the incremental encoder, directional zero-finding can be completed within 180 degrees, solving the problem of position information loss after power failure in incremental encoders, improving start-up speed and avoiding mechanical collisions.
Patent Information
- Application Number
- CN202423252995.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2034-12-27
AI Technical Summary
Incremental encoders cannot provide absolute position information after power failure, requiring a long time to complete a full rotation to find zero, and may cause mechanical collisions.
A zero-finding code channel is added to the existing incremental code channel and zero-position pulse code channel. The relative position of the incremental count reading head and the zero-position pulse code channel is determined by the output signal of the zero-finding code channel, so as to achieve directional zero finding within 180 degrees.
It shortens the encoder zero-finding time, avoids mechanical collisions, improves design flexibility, and facilitates integration and miniaturization.
Smart Images
Figure CN223538331U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of encoder technology, specifically providing a grating code disk and incremental encoder capable of directional zero finding. Background Technology
[0002] Encoders can be classified into two types based on their signal principle: absolute and incremental. An absolute encoder is a sensor that can accurately represent the position of an object in digital form. They typically include a fixed component and a rotatable or movable component, and use optical, magnetic, or acoustic technologies to capture position information. In an absolute encoder, each position can be defined as an absolute zero point, so the device does not need to find a zero point during startup, and the position information is not lost even when power is off.
[0003] Incremental encoders convert displacement into periodic electrical signals, which are then converted into counting pulses. The magnitude of the displacement is represented by the number of pulses. This type of encoder has a unique zero-point position within its cycle. For example... Figure 1 As shown, the grating disk of an incremental encoder typically contains A / B incremental code tracks and a Z code track. When the grating disk rotates, the incremental code tracks generate A and B signals with a 90° phase difference. By simultaneously acquiring these two signals, the speed and direction of the device's movement can be calculated. If both phase B and phase A initially read high (1,1), then B remains high while A becomes low (1,0), it indicates that the device is rotating clockwise; if both phase B and phase A initially read low (0,0), then B becomes high while A remains low (1,0), it indicates that the device is rotating counter-clockwise. In addition to the A and B channels, there is an additional Z channel signal, which indicates the encoder's specific reference position. Each time the sensor rotates, the Z-axis signal outputs a pulse, at which point the absolute position of the grating disk can be calculated by resetting the counts of the A and B channels.
[0004] However, incremental encoders can only provide information on the device's position change and direction of movement, not absolute position information, and therefore lose their zero position after power failure. Each time the device starts up, a long full-turn zeroing process is required, which is not only time-consuming but may also lead to mechanical collisions if the encoder's mechanical structure has limitations. Utility Model Content
[0005] In view of this, the present invention aims to provide a grating code disk and incremental encoder that can realize directional zero finding. Based on the existing incremental code track (A / B code track) and zero pulse code track (Z code track), a zero finding code track is added. When the encoder is powered on, the zero finding signal is output through the zero finding code track to determine the relative position of the incremental counting head and the zero pulse code track. By rotating in a preset direction, zero finding can be completed within 180 degrees, which shortens the encoder zero finding time and avoids encoder mechanical collision.
[0006] To achieve the above objectives, the technical solution created by this utility model is implemented as follows:
[0007] This invention provides a grating code disk capable of directional zero finding, comprising: an incremental code track and a zero-position pulse code track for reading via an incremental counting head. The invention is characterized by further comprising: a zero-finding code track for reading via a zero-finding reading head, the zero-finding code track including a light-transmitting area of 0 to 180 degrees and a non-light-transmitting area of 0 to -180 degrees. The light-transmitting and non-light-transmitting areas are used to output zero-finding signals with opposite levels. The zero-finding signals are used to determine the relative position of the incremental counting head and the zero-position pulse code track. Based on the zero-finding signals, the grating code disk is driven to rotate in the preset increment or decrement direction of the incremental code track, achieving directional zero finding within 180 degrees.
[0008] Preferably, the radial width of the zero-finding track is greater than or equal to 0.2 mm.
[0009] Preferably, the boundary between the light-transmitting area and the non-light-transmitting area can be set at any angle around the entire circumference of the grating code disk.
[0010] In another aspect, this invention provides an incremental encoder, comprising: an incremental counting read head, a zero-finding read head, and a grating code disk capable of directional zero-finding, wherein when the zero position is aligned, the boundary line between the light-transmitting area and the non-light-transmitting area is aligned with the zero-finding read head.
[0011] Preferably, the grating code disk rotates clockwise for counting up and counterclockwise for counting down.
[0012] Preferably, when the grating code disk rotates in the counting direction, the boundary line from the non-transparent area to the transparent area is defined as the first boundary line, and the boundary line from the transparent area to the non-transparent area is defined as the second boundary line.
[0013] Preferably, when the zero-finding reading head is located in the light-transmitting area, the zero-finding signal is high-level; when the zero-finding reading head is located in the non-light-transmitting area, the zero-finding signal is low-level; when the zero position is aligned, the zero-finding reading head is aligned with the first dividing line.
[0014] When the zero-finding reading head outputs a high-level zero-finding signal, the grating code disk for directional zero-finding can rotate in the decreasing counting direction to find zero.
[0015] When the zero-finding signal output by the zero-finding reading head is low, the grating code disk for directional zero-finding can rotate in the counting direction to find zero.
[0016] Preferably, when the zero-finding reading head is located in the light-transmitting area, the zero-finding signal is high-level; when the zero-finding reading head is located in the non-light-transmitting area, the zero-finding signal is low-level; when the zero position is aligned, the zero-finding reading head is aligned with the second dividing line.
[0017] When the zero-finding reading head outputs a high-level zero-finding signal, the grating code disk for directional zero-finding can rotate in the counting direction to find zero.
[0018] When the zero-finding signal output by the zero-finding reading head is low, the grating code disk can rotate in the direction of decreasing the count to find zero.
[0019] Compared with the prior art, the present invention can achieve the following beneficial effects:
[0020] This invention adds a zero-finding code track to the traditional incremental encoder grating code disk, enabling directional zero-finding. The level signal output from the zero-finding code track determines the relative position of the incremental counting head and the zero-position pulse code track. By rotating in a preset increment or decrement direction, zero-finding can be completed within 180°, effectively shortening the zero-finding time of the incremental encoder. The design of the zero-finding code track allows the encoder to quickly determine the zero position, which is crucial for encoder startup and calibration, significantly reducing system startup time. Furthermore, because zero-finding can be completed within 180°, mechanical collisions of the encoder are avoided under mechanical limiting conditions.
[0021] The interval boundary line of the zero-finding code track of this invention can be set at any position on the full circle, which improves the design flexibility. The position of the zero-finding code track can be adjusted according to different application requirements. In addition, the zero-finding code track is a single-circle code track. Compared with the existing complex zero-finding designs, the structure of this invention is simpler and easier to integrate into existing systems, which is conducive to the miniaturization of incremental encoders. Attached Figure Description
[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of this invention. The illustrative embodiments and descriptions of this invention are used to explain this invention and do not constitute an undue limitation of this invention. In the drawings:
[0023] Figure 1 This is a schematic diagram of the code track pattern and output signal of an existing incremental grating code disk in the background technology;
[0024] Figure 2 This is a schematic diagram of the code track pattern of a grating code disk capable of directional zero finding, provided according to an embodiment of the present utility model;
[0025] Figure 3 This is a schematic diagram showing the positions of the incremental counting head and the zero-finding reading head according to an embodiment of the present invention;
[0026] Figure 4 This is a schematic diagram of the zero-finding reading process provided according to an embodiment of the present utility model.
[0027] The reference numerals in the figures include:
[0028] Incremental code track 1, zero-position pulse code track 2, zero-finding code track 3, light-transmitting area 31, non-light-transmitting area 32, first dividing line 33, second dividing line 34, incremental counting reading head 4, zero-finding reading head 5. Detailed Implementation
[0029] To make the purpose, technical solution, and advantages of this utility model clearer, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this utility model. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to this utility model are not shown or described in the specification. This is to avoid obscuring the core parts of this utility model with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.
[0030] It should be noted that, without conflict, the embodiments and features in the embodiments of this utility model can be combined with each other to form various implementation methods. Furthermore, the steps or actions in the method description can be rearranged or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.
[0031] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.
[0032] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0033] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0034] Please see Figure 2 and Figure 3In one embodiment of this utility model, a grating code disk capable of directional zero-finding is provided, comprising: an incremental code track 1, a zero-position pulse code track 2, and a zero-finding code track 3. The incremental code track 1 and the zero-position pulse code track 2 are common designs for existing incremental encoder grating code disks. The incremental code track 1, also known as the A / B incremental code track, is read through the incremental counting head 4. In an incremental encoder, the A signal and the B signal are two signals with a 90-degree (or 1 / 4 cycle) phase difference, i.e., sine and cosine signals, used to determine the rotation direction and counting. If the A signal changes before the B signal (e.g., the A signal changes from low to high, then the B signal changes from low to high), it indicates that the encoder grating code disk is rotating clockwise, and this rotation direction increases the encoder count, i.e., the counting direction is increasing. If the B signal changes before the A signal, it indicates that the encoder grating code disk is rotating counterclockwise, and this rotation direction decreases the encoder count, i.e., the counting direction is decreasing. Zero-position pulse track 2, also known as the Z track, is also read through incremental counter reading head 4. Therefore, incremental counter reading head 4 is actually the ABZ signal chip. Zero-position pulse track 2 has a zero-position pulse marker, outputting only one pulse signal per revolution of the encoder grating code disk to determine the encoder's zero position. The main function of zero-position pulse track 2 is to provide a reference point, enabling the system to determine the absolute position of the encoder.
[0035] The incremental encoder outputs square wave pulse signals A, B, and Z through incremental code track 1 and zero-position pulse code track 2. The phase difference between the A and B pulse signals is 90 degrees, which is used to determine the rotation direction of the encoder motor. The Z phase outputs one pulse per revolution, providing an initial zero-position signal for the encoder. Therefore, the incremental encoder needs to perform zero finding first after each power-on, so that the incremental counting head 4 is aligned with the zero-position pulse mark on the zero-position pulse code track 2.
[0036] The existing incremental encoder's grating code disk only has an incremental code track 1 and a zero-position pulse code track 2. After the encoder is powered on, it cannot determine the relative position relationship between the zero-position pulse mark on the zero-position pulse code track 2 and the incremental counting reading head 4. Therefore, it can only perform a full circle zero search, which takes a long time. More importantly, the encoder usually has a mechanical limit switch, so the limit switch may be triggered during the full circle zero search, resulting in mechanical collision.
[0037] To shorten the zero-finding time and avoid mechanical collisions caused by full-circle zero-finding, this embodiment of the invention adds a zero-finding code track 3 to the incremental code track 1 and the zero-position pulse code track 2. The zero-finding code track 3 is concentrically marked with the incremental code track 1 and the zero-position pulse code track 2, and includes two sections: a light-transmitting area 31 with a central angle of 0 to 180 degrees and a non-light-transmitting area 32 with a central angle of 0 to -180 degrees. Unlike the incremental code track 1 and the zero-position pulse code track 2, the zero-finding code track 3 does not read signals through the incremental counting reading head 4, but instead reads signals through the zero-finding reading head 5, which is initially set at the boundary between the light-transmitting area 31 and the non-light-transmitting area 32. The signal read by the zero-finding code track 3 is called the zero-finding signal, which is used to determine the relative position of the incremental counting reading head 4 and the zero-position pulse code track 2. It can be understood that the initial state refers to the alignment position of the zero-finding reading head 5 and the zero-finding code track 3 when the encoder is zero-aligned.
[0038] The boundary line between the light-transmitting area 31 and the non-light-transmitting area 32 of the zero-finding code track 3 can be located at any position on the entire circumference of the encoder grating. To ensure the quality of the zero-finding signal, the radial width of the zero-finding code track 3 should be greater than or equal to 0.2 mm. During the reading process of the zero-finding code track 3, the levels of the zero-finding signals output from the light-transmitting area 31 and the non-light-transmitting area 32 are opposite. It can be understood that when the zero-finding reading head 5 is aligned with the light-transmitting area 31, the signal output by the zero-finding reading head 5 is either high or low, defined as a flag bit "1" or "0". Whether it is defined as high or low can be set manually. What needs to be met is that the signal level output by the zero-finding reading head 5 when aligned with the non-light-transmitting area 32 is opposite to that when aligned with the light-transmitting area 31.
[0039] Furthermore, since there are two dividing lines between the light-transmitting area 31 and the non-light-transmitting area 32, namely the first dividing line 33 and the second dividing line 34, and whether the zero-finding reading head 5 is set at the first dividing line 33 or the second dividing line 34 in the initial state will affect the rotation direction of the grating code disk driven by the zero-finding signal, i.e., the counting direction or the counting direction. Therefore, it is necessary to preset the rotation direction of the grating code disk according to the initial setting position of the zero-finding reading head 5. Further, the zero-finding direction of the grating code disk can be determined by whether the zero-finding signal is high or low, thereby achieving directional zero-finding within 180 degrees.
[0040] In this embodiment of the invention, a grating code disk capable of directional zero-finding is further applied to an incremental encoder. The directional zero-finding process of the grating code disk capable of directional zero-finding is described through an actual zero-finding scenario. For details, please refer to [link to documentation]. Figure 4The incremental encoder includes an incremental counting head 4, a zero-finding head 5, and a grating code disk capable of directional zero-finding. When zero is aligned, i.e., when the incremental counting head 4 is aligned with the zero-position pulse mark on the zero-position pulse code track 2, the zero-finding head 5 is positioned at the boundary line between the light-transmitting area 31 and the non-light-transmitting area 32. Since there are two boundary lines between the light-transmitting area 31 and the non-light-transmitting area 32, and the zero-finding head 5 is positioned at these two boundary lines, the subsequent zero-finding direction determination is completely opposite. Therefore, the zero-finding process is described in two cases:
[0041] First, it is clearly defined that clockwise rotation of the grating code disk is the counting direction, and counterclockwise rotation is the counting direction. When the grating code disk rotates in the counting direction, the boundary line transitioning from the non-transparent area 32 to the transparent area 31 is defined as the first boundary line 33, and the boundary line transitioning from the transparent area 31 to the non-transparent area 32 is defined as the second boundary line 34. It can be understood that when the grating code disk rotates clockwise, the boundary line through which the zero-finding reading head 5 changes its alignment from the non-transparent area 32 to the transparent area 31 is the first boundary line 33, and the other boundary line is the second boundary line 34. The definitions of the first boundary line 33 and the second boundary line 34 are for descriptive purposes only and do not specifically refer to any particular boundary line; they can be defined independently during the encoder design process.
[0042] Furthermore, when the zero-finding reading head 5 is located in the light-transmitting area 31, the output zero-finding signal is high, i.e., output "1"; when the zero-finding reading head 5 is located in the non-light-transmitting area 32, the output zero-finding signal is low, i.e., output "0".
[0043] In the first scenario, when the zero position is aligned, the zero-finding reading head 5 is aligned with the first dividing line 31. In this case, if the zero-finding signal output by the zero-finding reading head 5 is high (i.e., flag "1") when the encoder is powered on, the grating code disk for directional zero-finding can be preset to rotate in the direction of flag "0", i.e., rotating in the decrementing direction for zero-finding. If the zero-finding signal output by the zero-finding reading head 5 is low (i.e., flag "0") when the encoder is powered on, the grating code disk for directional zero-finding can be preset to rotate in the direction of flag "1", i.e., rotating in the incrementing direction for zero-finding. Figure 4 As shown, when the encoder is powered on, the zero-position pulse marker of the zero-position pulse code track 2 is 10 degrees clockwise on the incremental counting reading head 4. At this time, the zero-finding reading head 5 is in the light-transmitting area 31, and its output signal is high. The grating code disk that can achieve directional zero-finding should rotate towards the low-level direction. The preset grating code disk rotates in the decrementing direction, and a 10-degree rotation is sufficient to complete the zero-finding. Here, the rotation in the decrementing direction is the result of the rotation direction determination, which is preset based on the initial installation position of the zero-finding reading head 5.
[0044] In the second scenario, when the zero position is aligned, the zero-finding reading head 5 is aligned with the second dividing line 32. In this case, if the zero-finding signal output by the zero-finding reading head 5 is high (i.e., flag "1") when the encoder is powered on, the grating code disk for directional zero-finding can be preset to rotate in the direction of flag "0," thus rotating in the direction of incrementing the count for zero-finding. If the zero-finding signal output by the zero-finding reading head 5 is low (i.e., flag "0") when the encoder is powered on, the grating code disk for directional zero-finding can be preset to rotate in the direction of flag "1," thus rotating in the direction of decrementing the count for zero-finding. As described above, based on the setting position of the zero-finding reading head 5 and the preset zero-finding direction under different level conditions, the encoder can automatically oriented and zero-find within 180 degrees according to the zero-finding signal output by the zero-finding reading head 5.
[0045] In summary, the above description is merely a preferred embodiment of this specification and is not intended to limit the scope of protection of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of protection of this specification.
[0046] The systems, apparatuses, modules, or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, a computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.
[0047] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0048] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.
[0049] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.
Claims
1. A grating code disk capable of directional zero finding, comprising: The incremental code channel and zero-position pulse code channel for reading via an incremental counting head are characterized by further comprising: a zero-finding code channel for reading via a zero-finding reading head, wherein the zero-finding code channel includes a light-transmitting area from 0 to 180 degrees and a non-light-transmitting area from 0 to -180 degrees, the light-transmitting area and the non-light-transmitting area are used to output zero-finding signals with opposite levels, the zero-finding signals are used to determine the relative position of the incremental counting head and the zero-position pulse code channel, and the grating code disk is driven to rotate in the preset increment or decrement direction of the incremental code channel according to the zero-finding signal to achieve directional zero-finding within 180 degrees.
2. The grating code disk capable of directional zero finding as described in claim 1, characterized in that, The radial width of the zero-finding code track is greater than or equal to 0.2 mm.
3. The grating code disk capable of directional zero finding as described in claim 1, characterized in that, The boundary between the light-transmitting area and the non-light-transmitting area can be set at any angle around the entire circumference of the grating code disk.
4. An incremental encoder, characterized in that, include: When the zero position is aligned, the boundary line between the light-transmitting area and the non-light-transmitting area of the incremental counting reading head, the zero-finding reading head, and the grating code disk capable of directional zero-finding as described in any one of claims 1 to 3 are aligned with the zero-finding reading head.
5. The incremental encoder as described in claim 4, characterized in that, The grating code disk rotates clockwise to increment the count and counterclockwise to decrement the count.
6. The incremental encoder as described in claim 5, characterized in that, When the grating code disk rotates in the counting direction, the boundary line from the non-transparent area to the transparent area is defined as the first boundary line, and the boundary line from the transparent area to the non-transparent area is defined as the second boundary line.
7. The incremental encoder as described in claim 6, characterized in that, When the zero-finding reading head is located in the light-transmitting area, the zero-finding signal is high; when the zero-finding reading head is located in the non-light-transmitting area, the zero-finding signal is low; when the zero position is aligned, the zero-finding reading head is aligned with the first dividing line. When the zero-finding signal output by the zero-finding reading head is high, the grating code disk that can realize directional zero-finding rotates in the decreasing counting direction to find zero; When the zero-finding signal output by the zero-finding reading head is low, the grating code disk that can realize directional zero-finding rotates in the counting direction to find zero.
8. The incremental encoder as described in claim 6, characterized in that, When the zero-finding reading head is located in the light-transmitting area, the zero-finding signal is high; when the zero-finding reading head is located in the non-light-transmitting area, the zero-finding signal is low; when the zero position is aligned, the zero-finding reading head is aligned with the second dividing line. When the zero-finding signal output by the zero-finding reading head is high, the grating code disk that can realize directional zero-finding rotates in the counting direction to find zero; When the zero-finding signal output by the zero-finding reading head is low, the grating code disk that can realize directional zero-finding rotates in the decreasing counting direction to find zero.