Grating code disc capable of realizing directional zero searching and incremental encoder

Abstract

The invention relates to the technical field of encoders, and particularly provides a grating code disc capable of realizing directional zero searching and an incremental encoder, comprising an incremental code channel and a zero pulse code channel which are used for reading through an incremental counting reading head, and a zero searching code channel which is used for reading through a zero searching reading head, one half of the zero-seeking code channel is a light-transmitting area, the other half of the zero-seeking code channel is a non-light-transmitting area, high level or low level is output through the light-transmitting area and the non-light-transmitting area to judge the relative position of the increment counting reading head and the zero-bit pulse code channel, and the grating code disc is driven to rotate in the plus counting direction or minus counting direction of the preset increment code channel according to the zero-seeking signal. And directional zero searching within 180 degrees is realized. The zero searching time of the incremental encoder is effectively shortened, the encoder can quickly determine the zero position through the design of the zero searching code channel, and mechanical collision in the zero searching process is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of encoders, and in particular provides a grating code disk and an incremental encoder capable of realizing directional zeroing. Background Art

[0002] Encoders can be divided into two types based on the signal principle: absolute and incremental. An absolute encoder is a sensor that can accurately represent the position of an object in digital form. They usually consist of a fixed part and a rotating or movable part, and use optical, magnetic or acoustic technology 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 the zero point when starting up, and the position information will not be lost even if the power is off.

[0003] The incremental encoder converts the displacement into a periodic electrical signal, and converts these signals into counting pulses, and the number of pulses is used to represent the magnitude of the displacement. This encoder has a unique zero position within its cycle. Figure 1 As shown, the grating disk of the incremental encoder usually contains A / B incremental code tracks and Z code tracks. When the grating disk rotates, the incremental code tracks generate A and B signals with a phase difference of 90°. By simultaneously acquiring these two signals, the speed and direction of the device can be calculated. If both B phase and A phase first read high level (1,1), then B remains high and A becomes low level (1,0), it means that the device is rotating clockwise; if both B phase and A phase first read low level (0,0), then B becomes high and A remains low level (1,0), it means that the device is rotating counterclockwise. In addition to the A and B channels, there is an additional Z channel signal, which indicates a specific reference position of the encoder. The Z-axis signal outputs a pulse for each rotation of the sensor, at which time the absolute position of the grating disk can be calculated by resetting the counts of the A and B channels.

[0004] However, the incremental encoder can only provide the position change and movement direction information of the device, but cannot provide the absolute position information, so the zero position will be lost after power failure. Every time the device is started, a long full circle zero search is required, which is not only time-consuming, but also may cause mechanical collision when there is a limit in the mechanical structure of the encoder. Summary of the invention

[0005] In view of this, the present invention aims to provide a grating code disk and an incremental encoder that can realize directional zeroing. On the basis of the existing incremental code channel (A / B code channel) and the zero-position pulse code channel (Z code channel), a zero-seeking code channel is added. When the encoder is powered on, a zero-seeking signal is output through the zero-seeking code channel to determine the relative position of the incremental counting reading head and the zero-position pulse code channel. Zeroing can be completed within 180 degrees by rotating in a preset direction, thereby shortening the encoder's zeroing time and avoiding mechanical collision of the encoder.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows: The invention provides, on the one hand, a grating code disk capable of realizing directional homing, comprising: an incremental code track and a zero pulse code track for reading by an incremental counting reading head, characterized in that it also comprises: a homing code track for reading by a homing reading head, the homing code track comprising a light-transmitting area of ​​0 to 180 degrees and a non-light-transmitting area of ​​0 to -180 degrees, the light-transmitting area and the non-light-transmitting area being used to output homing signals with opposite levels, the homing signals being used to determine the relative position of the incremental counting reading head and the zero pulse code track, and the grating code disk being driven to rotate in the preset incrementing direction or the decrementing direction of the incremental code track according to the homing signal, thereby realizing directional homing within 180 degrees.

[0007] Preferably, the radial width of the zero-seeking code track is greater than or equal to 0.2 mm.

[0008] Preferably, the boundary line between the light-transmitting area and the non-light-transmitting area can be set at any angle of the entire circumference of the grating code disk.

[0009] Another aspect of the invention provides an incremental encoder, including: an incremental counting reading head, a homing reading head and a grating code disk capable of directional homing. When zero position is aligned, the boundary line between the light-transmitting area and the non-light-transmitting area is aligned with the homing reading head.

[0010] Preferably, the grating code disk rotates clockwise for the count-up direction, and rotates counterclockwise for the count-down direction.

[0011] Preferably, when the grating code disk rotates in the counting direction, the boundary line of transition from the non-light-transmitting area to the light-transmitting area is defined as the first boundary line, and the boundary line of transition from the light-transmitting area to the non-light-transmitting area is defined as the second boundary line.

[0012] Preferably, it is defined that when the homing reading head is located in the light-transmitting area, the homing signal is at a high level, and when the homing reading head is located in the non-light-transmitting area, the homing signal is at a low level; when the zero position is aligned, the homing reading head is aligned with the first dividing line; When the homing signal output by the homing reading head is at a high level, the grating code disk for directional homing can be rotated in the direction of down counting to homing; When the homing signal output by the homing reading head is at a low level, the grating code disk that can realize directional homing can rotate in the counting direction to homing.

[0013] Preferably, it is defined that when the homing reading head is located in the light-transmitting area, the homing signal is at a high level, and when the homing reading head is located in the non-light-transmitting area, the homing signal is at a low level; when the zero position is aligned, the homing reading head is aligned with the second dividing line; When the homing signal output by the homing reading head is at a high level, the grating code disk for directional homing can be rotated in the counting direction to homing; When the homing signal output by the homing reading head is at a low level, the grating code disk for directional homing can be rotated in the direction of down counting to search for homing.

[0014] Compared with the prior art, the invention can achieve the following beneficial effects:

[0015] The present invention adds a homing code track that can realize directional homing on the basis of the traditional incremental encoder grating code disk. The relative position of the incremental counting reading head and the zero pulse code track can be judged by the level signal output by the homing code track. By rotating in the preset plus counting direction or minus counting direction, homing can be completed within 180°, effectively shortening the homing time of the incremental encoder. The design of the homing code track enables the encoder to quickly determine the zero position, which is crucial for the encoder startup and calibration process and can significantly reduce the system startup time. And because homing can be completed within 180°, mechanical collision of the encoder is avoided under mechanical limit conditions.

[0016] The interval dividing line of the homing code channel of the present invention can be set at any position of the entire circle, which improves the design flexibility and can adjust the position of the homing code channel according to different application requirements. In addition, the homing code channel is a single-circle code channel. Compared with the existing complex homing design, the structure of the present invention is simpler and easier to integrate into the existing system, which is conducive to the miniaturization of the incremental encoder. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 It is a schematic diagram of a code pattern and output signal of an existing incremental grating code disc in the background technology; Figure 2 is a schematic diagram of a code track pattern of a grating code disk capable of achieving directional zeroing provided by an embodiment of the present invention; Figure 3 is a schematic diagram of the positions of an incremental counting reading head and a homing reading head provided in an embodiment of the present invention; Figure 4 Schematic diagram of a zero-seeking reading process provided according to an embodiment of the present invention.

[0018] Reference numerals include: Incremental code channel 1, zero pulse code channel 2, zero-seeking code channel 3, light-transmitting area 31, non-light-transmitting area 32, first dividing line 33, second dividing line 34, incremental counting reading head 4, zero-seeking reading head 5. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the invention clearer, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the invention and do not constitute a limitation to the invention. Similar components in different embodiments use associated similar component numbers. In the following embodiments, many detailed descriptions are to enable the invention to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other components, materials, and methods. In some cases, some operations related to the invention are not shown or described in the specification, in order to avoid the core part of the invention being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0020] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0021] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0022] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0023] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0024] See also Figure 2 and Figure 3 In one embodiment of the present invention, a grating code disk capable of directional zeroing is provided, comprising: an incremental code track 1, a zero pulse code track 2 and a zeroing code track 3, wherein the incremental code track 1 and the zero pulse code track 2 are common designs of existing incremental encoder grating code disks, the incremental code track 1 is also called an A / B incremental code track, and is read by an incremental counting reading head 4. In an incremental encoder, the A signal and the B signal are two signals with a phase difference of 90 degrees (or 1 / 4 cycle) used to determine the rotation direction and count, namely, sine and cosine signals. If the A signal changes before the B signal (for example, the A signal changes from low to high, and then the B signal changes from low to high), it means that the encoder grating code disk is rotating clockwise, and this rotation direction causes the encoder count to increase, namely, the plus counting direction; if the B signal changes before the A signal, it means that the encoder grating code disk is rotating counterclockwise, and this rotation direction causes the encoder count to decrease, namely, the minus counting direction. The zero pulse code channel 2 is also called the Z code channel. The zero pulse code channel 2 is also read by the incremental counting reading head 4, so the incremental counting reading head 4 is actually the ABZ signal chip. There is a zero pulse mark on the zero pulse code channel 2. When the encoder grating code disk rotates one circle, only one pulse signal is output to determine the zero position of the encoder. The main function of the zero pulse code channel 2 is to provide a reference point so that the system can determine the absolute position of the encoder.

[0025] The incremental encoder outputs square wave pulse signals A, B and Z through the incremental code channel 1 and the zero pulse code channel 2; the phase difference between the two groups of pulse signals A and B is 90 degrees, which is used to determine the rotation direction of the encoder motor. The Z phase outputs a pulse per revolution to provide an initial zero signal for the encoder. Therefore, the incremental encoder needs to be zeroed every time it is powered on, so that the incremental counting reading head 4 is aligned with the zero pulse mark on the zero pulse code channel 2.

[0026] The grating code disk of the existing incremental encoder is only provided with incremental code track 1 and zero position pulse code track 2. After the encoder is powered on, it is impossible to 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 full circle zeroing, and the zeroing time is relatively long. More importantly, the encoder is usually provided with mechanical limit, so the limit may be triggered during the full circle zeroing process, resulting in mechanical collision.

[0027] In order to shorten the zero-seeking time and avoid mechanical collision caused by full-circle zero-seeking, the embodiment of the present invention adds a zero-seeking code track 3 on the basis of the incremental code track 1 and the zero-position pulse code track 2. The zero-seeking code track 3 is concentrically depicted with the incremental code track 1 and the zero-position pulse code track 2, and includes two intervals, namely, a light-transmitting area 31 corresponding to a center angle of 0 to 180 degrees and a non-light-transmitting area 32 corresponding to a center angle of 0 to -180 degrees. Different from the incremental code track 1 and the zero-position pulse code track 2, the zero-seeking code track 3 does not read the signal through the incremental counting reading head 4, but reads the signal through the zero-seeking reading head 5 which is initially set at the boundary position of the light-transmitting area 31 and the non-light-transmitting area 32. The signal obtained by reading the zero-seeking code track 3 is called the zero-seeking signal, and the zero-seeking signal 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-seeking reading head 5 and the zero-seeking code track 3 when the encoder is aligned at zero position.

[0028] The boundary line between the light-transmitting area 31 and the non-light-transmitting area 32 of the zero-seeking code channel 3 can be at any position of the encoder grating throughout the entire circumference. In order to ensure the quality of the zero-seeking signal, the radial width of the zero-seeking code channel 3 should be greater than or equal to 0.2 mm. During the reading process of the zero-seeking code channel 3, the levels of the zero-seeking signals output by the light-transmitting area 31 and the non-light-transmitting area 32 are opposite. It can be understood that when the zero-seeking reading head 5 is aligned with the light-transmitting area 31, the signal output by the zero-seeking reading head 5 is a high level or a low level, which is defined as a flag bit "1" or "0". The specific definition of high level or low level can be set manually. What needs to be satisfied is that the signal level output when the zero-seeking reading head 5 is aligned with the non-light-transmitting area 32 is opposite to that when it is aligned with the light-transmitting area 31.

[0029] In addition, 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 in the initial state, whether the homing reading head 5 is set at the first dividing line 33 or the second dividing line 34 will affect the rotation direction of the grating code disk driven according to the homing signal, namely, 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 state setting position of the homing reading head 5. Further, the homing direction of the grating code disk can be determined according to whether the homing signal is high or low, thereby realizing directional homing within 180 degrees.

[0030] In the embodiment of the present invention, the grating code disk capable of realizing directional homing is further applied to the incremental encoder, and the directional homing process of the grating code disk capable of realizing directional homing is described through the actual homing scenario. For details, please refer to Figure 4 The incremental encoder includes: an incremental counting reading head 4, a homing reading head 5, and a grating code disk capable of realizing directional homing. When zero is aligned, that is, when the incremental counting reading head 4 is aligned with the zero pulse mark on the zero pulse code track 2, the homing reading head 5 is arranged at the boundary position between the light-transmitting area 31 and the non-light-transmitting area 32. Since the boundary lines between the light-transmitting area 31 and the non-light-transmitting area 32 include two, and when the homing reading head 5 is arranged at the two boundary lines, the subsequent homing direction determination is completely opposite. Therefore, the homing process is described in two cases: First, it is clear that the grating code disk rotates clockwise for the count-up direction and counterclockwise for the count-down direction, and it is defined that when the grating code disk rotates in the count-up direction, the boundary line of the transition from the non-light-transmitting area 32 to the light-transmitting area 31 is defined as the first boundary line 33, and the boundary line of the transition from the light-transmitting area 31 to the non-light-transmitting 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-seeking reading head 5 passes when the alignment position changes from the non-light-transmitting area 32 to the light-transmitting area 31 is the first boundary line 33, and the other boundary line is the second boundary line 34. The definition of the first boundary line 33 and the second boundary line 34 is only for the convenience of description, and does not specifically refer to a certain boundary line, and can be defined by oneself during the encoder design process.

[0031] In addition, it is defined that when the homing reading head 5 is located in the light-transmitting area 31, the output homing signal is a high level, that is, the output is "1"; when the homing reading head 5 is located in the non-light-transmitting area 32, the output homing signal is a low level, that is, the output is "0".

[0032] In the first case, when the zero position is aligned, the homing reading head 5 is aligned with the first dividing line 31. In this case, if the homing signal output by the homing reading head 5 is high level when the encoder is powered on, that is, the flag "1", then the grating code disk for directional homing is preset to rotate in the direction of the flag "0", that is, to rotate in the direction of the count down to search for zero. If the homing signal output by the homing reading head 5 is low level when the encoder is powered on, that is, the flag "0", then the grating code disk for directional homing is preset to rotate in the direction of the flag "1", that is, to rotate in the direction of the count up to search for zero. Figure 4 As shown, when the encoder is powered on, the zero pulse mark of the zero pulse code channel 2 is in the 10 degree direction of the incremental counting reading head 4 clockwise. At this time, the homing reading head 5 is in the light-transmitting area 31, and its output signal is high level. The grating code disk that can realize directional homing should rotate in the low level direction. The grating code disk is preset to rotate in the direction of the count down, and the homing can be completed by rotating 10 degrees. Among them, the rotation in the count down direction is the result of the determination of the rotation direction, which is the preset installation position according to the initial state of the homing reading head 5.

[0033] In the second case, when the zero position is aligned, the homing reading head 5 is aligned with the second dividing line 32. In this case, if the homing signal output by the homing reading head 5 is high level when the encoder is powered on, that is, the flag "1", the grating code disk that can realize directional homing is preset to rotate in the direction of the flag "0", and at this time, it is set to rotate in the counting direction for homing. If the homing signal output by the homing reading head 5 is low level when the encoder is powered on, that is, the flag "0", the grating code disk that can realize directional homing is preset to rotate in the direction of the flag "1", that is, it is set to rotate in the counting direction for homing. It can be seen from the above description that according to the setting position of the homing reading head 5, after the homing direction under different power levels is preset, the encoder can automatically directional homing within 180 degrees according to the homing signal output by the homing reading head 5.

[0034] In short, the above description is only a preferred embodiment of this specification and is not intended to limit the protection scope of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this specification shall be included in the protection scope of this specification.

[0035] The systems, devices, 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, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0036] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0037] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0038] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A grating code disc capable of realizing directional zeroing, comprising: The incremental code channel and the zero pulse code channel are read by the incremental counting reading head, characterized in that it also includes: a zero-seeking code channel for reading by the zero-seeking reading head, the zero-seeking code channel includes a light-transmitting area of ​​0 to 180 degrees and a non-light-transmitting area of ​​0 to -180 degrees, the light-transmitting area and the non-light-transmitting area are used to output zero-seeking signals with opposite levels, the zero-seeking signal is used to determine the relative position of the incremental counting reading head and the zero pulse code channel, and the grating code disk is driven to rotate in the preset increment counting direction or decrement counting direction of the incremental code channel according to the zero-seeking signal to achieve directional zeroing within 180 degrees.

2. The grating code disc capable of achieving directional homing according to claim 1, characterized in that: The radial width of the zero-seeking code track is greater than or equal to 0.2 mm.

3. The grating code disc capable of achieving directional zeroing according to claim 1, characterized in that: The boundary line between the light-transmitting area and the non-light-transmitting area can be set at any angle of the entire circumference of the grating code disk.

4. An incremental encoder, characterized in that: include: The incremental counting reading head, the homing reading head and the grating code disk capable of directional homing as described in any one of claims 1 to 3, when the zero position is aligned, the boundary line between the light-transmitting area and the non-light-transmitting area is aligned with the homing reading head.

5. The incremental encoder according to claim 4, characterized in that The grating code disk rotates clockwise for the count-up direction, and counterclockwise for the count-down direction.

6. The incremental encoder according to claim 5, characterized in that When the grating code disk rotates in the counting direction, the boundary line transitioning from the non-light-transmitting area to the light-transmitting area is defined as the first boundary line, and the boundary line transitioning from the light-transmitting area to the non-light-transmitting area is defined as the second boundary line.

7. The incremental encoder according to claim 6, characterized in that It is defined that when the homing reading head is located in the light-transmitting area, the homing signal is at a high level, and when the homing reading head is located in the non-light-transmitting area, the homing signal is at a low level; when the zero position is aligned, the homing reading head is aligned with the first dividing line; When the homing signal output by the homing reading head is at a high level, the grating code disk capable of realizing directional homing rotates in a down counting direction to homing; When the homing signal output by the homing reading head is at a low level, the grating code disk capable of realizing directional homing rotates in the counting direction to homing.

8. The incremental encoder according to claim 6, characterized in that It is defined that when the homing reading head is located in the light-transmitting area, the homing signal is at a high level, and when the homing reading head is located in the non-light-transmitting area, the homing signal is at a low level; when the zero position is aligned, the homing reading head is aligned with the second dividing line; When the homing signal output by the homing reading head is at a high level, the grating code disk capable of realizing directional homing rotates in the counting direction to homing; When the homing signal output by the homing reading head is at a low level, the grating code disk capable of realizing directional homing rotates in the direction of down counting to search for homing.

Images