Zero calibration method and zero calibration device of encoder and storage medium

Abstract

The invention relates to a zero calibration method of an encoder, a zero calibration device and a storage medium. The encoder comprises a magnetic stripe track and a magnetic field detection element, the magnetic stripe track comprises a first magnetic field section and a second magnetic field section, the magnetic field characteristic of the first magnetic field section is different from that of the second magnetic field section, and the magnetic field detection element moves along the magnetic stripe track; the method comprises the following steps: acquiring magnetic field induction signals corresponding to magnetic field characteristics at different positions of a magnetic strip track through a magnetic field detection element; and performing zero calibration on the encoder based on the magnetic field induction signal. By adopting the method, the accuracy of zero calibration of the encoder can be improved.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a zero position calibration method, a zero position calibration device and a storage medium for an encoder. Background Art

[0002] When the encoder is powered on again after being disconnected, it needs to be recalibrated to ensure that the displacement of the moving parts can be accurately encoded to sense the position information of the moving parts.

[0003] In the related art, the zero position calibration of the encoder can be performed mechanically or photoelectrically. Among them, the mechanical method is to determine whether the stall current of the motor driving the moving part meets the preset conditions. This method will reduce the life of the motor and reduce the reliability of the encoder during use. The photoelectric method is that when the moving part touches the laser, a trigger signal is generated. In this method, the assembly process of the photoelectric sensor will cause errors, reducing the accuracy of the positioning code.

[0004] Therefore, the zero position calibration of the encoder in the related art has a great influence on the performance of the encoder. Summary of the invention

[0005] Based on this, it is necessary to provide a zero position calibration method, a zero position calibration device and a storage medium for an encoder, which can improve the accuracy of the zero position calibration of the encoder, in order to solve the above technical problems.

[0006] In a first aspect, the present application provides a method for zero position calibration of an encoder, the method comprising:

[0007] The encoder includes a magnetic stripe track and a magnetic field detection element, the magnetic stripe track includes a first magnetic field segment and a second magnetic field segment, the magnetic field characteristics of the first magnetic field segment are different from the magnetic field characteristics of the second magnetic field segment, and the magnetic field detection element moves along the magnetic stripe track; the zero position calibration method includes:

[0008] Obtaining magnetic field sensing signals corresponding to magnetic field characteristics at different positions of the magnetic track through a magnetic field detection element; and

[0009] Based on the magnetic field induction signal, the encoder is calibrated to zero position.

[0010] In one of the embodiments, an absolute value of a difference between the magnetic field characteristics of the second magnetic field segment and the magnetic field characteristics of the first magnetic field segment is greater than or equal to a preset magnetic field characteristic threshold.

[0011] In one embodiment, the magnetic field characteristic is the magnetic field intensity, the first magnetic field segment includes a first magnetic pole pair, the second magnetic field segment includes a second magnetic pole pair, the first magnetic pole pair is magnetized by a first pulse current, and the second magnetic pole pair is magnetized by a second pulse current; the current difference between the first pulse current and the second pulse current is greater than or equal to a preset current threshold.

[0012] In one embodiment, the magnetic field characteristic is the magnetic field intensity, the first magnetic field segment includes a first magnetic pole pair and the second magnetic field segment includes a second magnetic pole pair, the first magnetic pole pair and the second magnetic pole pair are made of materials with different magnetic powder densities; the magnetic powder density difference between the magnetic powder density of the material of the second magnetic pole pair and the magnetic powder density of the material of the first magnetic pole pair is greater than or equal to a preset magnetic powder density threshold.

[0013] In one embodiment, the magnetic field characteristic is the frequency of the magnetic field induction signal, the first magnetic field segment includes a first magnetic pole pair, the second magnetic field segment includes a second magnetic pole pair, and the arrangement density difference between the arrangement density of the first magnetic pole pair and the arrangement density of the second magnetic pole pair is greater than or equal to a preset arrangement density threshold.

[0014] In one embodiment, the encoder is zero-calibrated based on the magnetic field sensing signal, including:

[0015] Determine the signal difference between the magnetic field induction signal obtained at the current moment and the magnetic field strength signal obtained at the previous moment;

[0016] If the signal difference is greater than or equal to the preset difference threshold, the position of the magnetic field detection element relative to the magnetic track at the current moment is determined as the zero position of the encoder.

[0017] In one of the embodiments, the magnetic field detection element or the magnetic strip track is fixedly coupled to the moving part whose motion parameter is to be detected.

[0018] In one embodiment, the first magnetic field segment is made of a first material and the second magnetic field segment is made of a second material, and the magnetic property of the first material is different from the magnetic property of the first material.

[0019] In a second aspect, the present application further provides a zero position calibration device for an encoder, the encoder comprising a magnetic stripe track and a magnetic field detection element, the magnetic stripe track comprising a first magnetic field segment and a second magnetic field segment, the magnetic field characteristics of the first magnetic field segment are different from the magnetic field characteristics of the second magnetic field segment, and the magnetic field detection element moves along the magnetic stripe track; the device comprises:

[0020] an acquisition module, used to acquire magnetic field sensing signals corresponding to magnetic field characteristics at different positions of the magnetic track through a magnetic field detection element; and

[0021] The calibration module is used to calibrate the encoder to zero position based on the magnetic field induction signal.

[0022] In a third aspect, the present application further provides a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the content of any one embodiment of the encoder zero position calibration method in the first aspect is implemented.

[0023] In a fourth aspect, the present application further provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the content of any one embodiment of the zero position calibration method of the encoder in the first aspect is implemented.

[0024] In a fifth aspect, the present application further provides a computer program product, including a computer program, which, when executed by a processor, implements the content of any one embodiment of the zero position calibration method of an encoder in the first aspect.

[0025] The zero position calibration method, zero position calibration device and storage medium of the above-mentioned encoder, the encoder includes a magnetic stripe track and a magnetic field detection element, the magnetic stripe track includes a first magnetic field segment and a second magnetic field segment, the magnetic field characteristics of the first magnetic field segment are different from the magnetic field characteristics of the second magnetic field segment, and the magnetic field detection element moves along the magnetic stripe track; through the magnetic field detection element, a magnetic field induction signal corresponding to the magnetic field characteristics at different positions of the magnetic stripe track is obtained; and based on the magnetic field induction signal, the encoder is zero-calibrated. The method sets sections with different magnetic field characteristics on the magnetic track, so that the magnetic field induction signals detected by the magnetic field detection element in different sections are different. In this way, the magnetic field detection element measures the magnetic field induction signals at different positions on the magnetic track, and according to the magnetic field induction signal, the encoder can be accurately zero-calibrated. The whole process does not introduce other hardware equipment, reduces the random error of the encoder zero position calibration, and can improve the accuracy and reliability of the encoder zero position calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 An application environment diagram of a zero position calibration method for an encoder in one embodiment;

[0027] Figure 2 A schematic flow chart of a method for zero position calibration of an encoder in one embodiment;

[0028] Figure 3 is a first schematic diagram of a magnetic field sensing signal in one embodiment;

[0029] Figure 4 is a second schematic diagram of a magnetic field sensing signal in one embodiment;

[0030] Figure 5is a third schematic diagram of a magnetic field sensing signal in one embodiment;

[0031] Figure 6 A schematic flow chart of a method for zero position calibration of an encoder in one embodiment;

[0032] Figure 7 A schematic flow chart of a method for zero position calibration of an encoder in one embodiment;

[0033] Figure 8 is a schematic diagram of a scene of an encoder in an embodiment;

[0034] Fig. 9 is a schematic diagram of a scene of an encoder in an embodiment;

[0035] Fig.10 The figure is a structural block diagram of a zero position calibration device for an encoder in one embodiment. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0037] Before introducing the technical solution of the present application in detail, a brief introduction to the background technology of the present application is first given.

[0038] A position sensor is a device that can sense the position information of a target object and convert it into an electrical signal output through relevant mechanical and electrical connections. In actual applications, when controlling the motion process of a target object, the position sensor measures the linear or rotational motion of the target object, and converts the analog quantity into a digital quantity through the corresponding analog-to-digital processing circuit and outputs it to the receiving processing unit, which controls the motion of the target object based on this signal.

[0039] In addition, the position sensor is also an indispensable part of the closed-loop control system. Together with the feedback unit and the processing unit, it constitutes the speed closed loop and position closed loop of the control object, so as to more accurately control the speed and displacement of the target object.

[0040] An encoder is a type of position sensor that can be used to measure displacement or angle changes. According to the signal output form, it can be divided into incremental encoders and absolute encoders. In some specific fields (such as construction, medical, military, etc.), the space on the moving parts where the encoder can be installed is limited, and the installation process of the encoder is complex and harsh, with great environmental impact. Since the absolute encoder contains an electrically erasable programmable read-only memory (EEPROM) for storing position information, this type of memory has poor environmental tolerance and is easily affected by harsh environments such as moisture, dust or radiation, causing abnormal power supply and self-damage, increasing the product failure rate and the cost of repeated repairs. In this specific field, absolute encoders are not a good choice.

[0041] In order to improve the safety of encoders in specific fields, two sets of encoders are needed as position feedback to form a redundant design, so as to improve the control accuracy and ensure the safety of movement. However, there is a disadvantage of incremental encoders, that is, the encoder value is not saved when the power is off. If the power is turned on again, the incremental encoder needs to "seek zero" again.

[0042] In general, the "zero search" process uses mechanical or photoelectric methods to generate trigger signals, which are given to the processing circuit to clear or mark the incremental encoder's encoding value as a reference for the position. For mechanical methods, most of them use motor drive components to directly contact mechanical parts to determine whether the motor's stall current or stall time reaches a preset threshold to generate trigger signals. The mechanical method itself has a certain loss for the motor, and the longer it is used, the greater the loss to the motor, which will lead to a significant reduction in the life of the motor, an increase in the failure rate of components, and the reliability of the product cannot be guaranteed. For photoelectric methods, most of them use external photoelectric switch signals as the zero point. When the moving part moves to touch the laser, a trigger signal is generated and given to the processing circuit to mark the zero position. However, the external photoelectric sensor will have random assembly errors, which will introduce new errors to the motion system, increase the complexity of the motion control system, and reduce the in-place accuracy and repeatability of the motion control system. In addition, photoelectric sensors rely on the reflection of light beams during use, and their impact resistance is relatively weak. In actual use, they require a relatively high degree of environmental cleanliness. Otherwise, the light may be accidentally blocked, causing the incremental encoder to obtain an incorrect "zeroing" result.

[0043] In view of the above problems, the present application provides a method for zero position calibration of an encoder, which can improve the accuracy and reliability of zero position calibration of the encoder by distinguishing the magnetic field characteristics on the magnetic stripe track of the encoder and calibrating the encoder according to the magnetic field induction signal obtained by the movement of the magnetic field detection element on the magnetic stripe track. The encoder can be various types of encoders, such as an incremental encoder, or an encoder composed of an incremental encoder and an absolute encoder, and so on.

[0044] The zero position calibration method of the encoder provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. For example, the computer device may be a server, a personal computer, a laptop, a smart phone, a tablet computer, a smart mobile phone, etc. The computer device may include a processor, a memory and a network interface connected by a system bus or wirelessly. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device may include a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data during the zero position calibration process of the encoder. The network interface of the computer device is used to communicate with an external terminal through a network connection, and the computer program is executed by the processor to implement a zero position calibration method of an encoder. Among them, the computer device can be implemented by an independent computer device or a computer device cluster composed of multiple computer devices. It should be noted that the memory of the computer device is not limited to the above-mentioned memory, and may also include a high-speed random access memory, a volatile solid-state memory, etc. In addition, the composition architecture of the computer device is not limited to the above-mentioned situation, and some components may also be added or omitted.

[0045] In one embodiment, Figure 2 As shown, a method for zero position calibration of an encoder is provided, and the method is applied to Figure 1 The computer device in the example is used to illustrate, including the following steps:

[0046] The encoder includes a magnetic stripe track and a magnetic field detection element, the magnetic stripe track includes a first magnetic field segment and a second magnetic field segment, the magnetic field characteristics of the first magnetic field segment are different from the magnetic field characteristics of the second magnetic field segment, and the magnetic field detection element moves along the magnetic stripe track. As an example, the zero position calibration method may include:

[0047] S201, obtaining magnetic field induction signals corresponding to magnetic field characteristics at different positions of the magnetic track through a magnetic field detection element.

[0048] Among them, the magnetic track of the encoder refers to the track along which the magnetic field detection element moves relative to each other. For example, the magnetic track can be the track of the moving part during the movement, wherein the magnetic field detection element of the encoder moves on the magnetic track following the moving part, and the relative position between the magnetic field detection element and the moving part remains unchanged. The magnetic field detection element or the magnetic track can be fixedly coupled to the moving part whose motion parameters are to be detected. For example, the magnetic field detection element or the magnetic track can be fixedly connected to the moving part, or the magnetic field detection element can be fixed inside the moving part, and so on. As a non-limiting example, the above-mentioned motion parameters can be motion distance, speed, acceleration, rotation speed or other parameters, and so on.

[0049] The magnetic field detection element is an element used to detect the magnetic field generated by the magnetic strip track. For example, the magnetic field detection element can be a magnetometer, a Hall element, or a direction cosine meter, etc. In this article, the magnetic field detection element used in the encoder is mainly described as a Hall element.

[0050] The magnetic stripe track includes two magnetic field segments with different magnetic field characteristics, namely the first magnetic field segment and the second magnetic field segment. This embodiment does not limit the area, shape and position of the first magnetic field segment and the second magnetic field segment. For example, the area of ​​the first magnetic field segment and the second magnetic field segment are both half of the area of ​​the magnetic stripe track, and both are rectangular in shape. The first magnetic field segment is arranged on the left side of the magnetic stripe track, and the second magnetic field segment is arranged on the right side of the magnetic stripe track. The above-mentioned magnetic field characteristics can be magnetic field strength, magnetic field direction, or the presence or absence of magnetism. For example, the magnetic field strength of the first magnetic field segment is greater than the magnetic field strength of the second magnetic field segment; or, the magnetic field direction of the first magnetic field segment is opposite to the magnetic field direction of the second magnetic field segment; or, the first magnetic field segment or the second magnetic field segment is non-magnetic and the other magnetic field segment is magnetic. In addition, the magnetic stripe track may also include more than two magnetic field segments with different magnetic field characteristics, which will not be repeated here.

[0051] Furthermore, considering that the difference between the magnetic field characteristics of the first magnetic field segment and the second magnetic field segment is too small, resulting in a small difference in the magnetic field inductive signals of the two segments detected by the magnetic field detection element, the magnetic field characteristics of the first magnetic field segment and the second magnetic field segment can be further distinguished, that is, the absolute value of the difference between the magnetic field characteristics of the second magnetic field segment and the magnetic field characteristics of the first magnetic field segment is greater than or equal to the preset magnetic field characteristic threshold. In this case, whether the magnetic field characteristics of the second magnetic field segment are greater than the magnetic field characteristics of the first magnetic field segment, or the magnetic field characteristics of the first magnetic field segment are greater than the magnetic field characteristics of the second magnetic field segment, it is only necessary to satisfy that the absolute value of the difference between the two is greater than or equal to the preset magnetic field characteristic threshold.

[0052] When the magnetic field characteristic is magnetic field intensity, for example, two methods can be used to ensure that the absolute value of the magnetic field intensity difference between the magnetic field intensity corresponding to the second magnetic field segment and the magnetic field intensity corresponding to the first magnetic field segment is greater than or equal to a preset magnetic field intensity threshold.

[0053] In one method, the magnetic pole pairs in different magnetic field sections are magnetized by currents of different sizes. Specifically: the first magnetic field section includes a first magnetic pole pair, the second magnetic field section includes a second magnetic pole pair, the first magnetic pole pair is magnetized by a first pulse current, and the second magnetic pole pair is magnetized by a second pulse current; the current difference between the first pulse current and the second pulse current is greater than or equal to a preset current threshold. Since the current and magnetic field strength are proportional, that is, the larger the current, the greater the magnetic field strength. If the first pulse current I A Greater than the second pulse current I B , then use the first pulse current I A The first magnetic pole pair is magnetized, and a second pulse current I is used B After the second magnetic pole pair is magnetized, the magnetic field strength H of the first magnetic field section is A Greater than the magnetic field strength H of the second magnetic field section B , and the difference in magnetic field intensity between the first magnetic field segment and the second magnetic field segment is H A -H B Greater than or equal to a preset magnetic field strength difference. Alternatively, the second pulse current may be greater than the first pulse current. This process is opposite to the above process, and the result is: the magnetic field strength of the second magnetic field segment is greater than the magnetic field strength of the first magnetic field segment, and the difference in magnetic field strength between the second magnetic field segment and the first magnetic field segment is greater than or equal to a preset magnetic field strength difference. It should be noted that in this embodiment, the first magnetic pole pair and the second magnetic pole pair are made of the same raw material. For example, the two magnetic pole pairs can be made of materials such as iron, cobalt, nickel or ferrite.

[0054] In another way, the first magnetic pole pair and the second magnetic pole pair can also be made of materials with different magnetic powder densities, and the magnetic pole pairs made of different materials are magnetized using the same current, and the magnetic field strengths of the first magnetic field section and the second magnetic field section are also different. Specifically: the first magnetic field section includes the first magnetic pole pair and the second magnetic field section includes the second magnetic pole pair, and the first magnetic pole pair and the second magnetic pole pair are made of materials with different magnetic powder densities; the difference in magnetic powder density between the magnetic powder density of the material of the second magnetic pole pair and the magnetic powder density of the material of the first magnetic pole pair is greater than or equal to a preset magnetic powder density threshold. If the first magnetic pole pair is made of a material with a larger magnetic powder density and the second magnetic pole pair is made of a material with a smaller magnetic powder density, then, after the first magnetic pole pair and the second magnetic pole pair are magnetized using the same current, the magnetic field strength of the first magnetic field section is greater than the magnetic field strength of the second magnetic field section. Alternatively, if the first magnetic pole pair is made of a material with a lower magnetic powder density and the second magnetic pole pair is made of a material with a higher magnetic powder density, then after the first magnetic pole pair and the second magnetic pole pair are magnetized by currents of the same magnitude, the magnetic field strength of the second magnetic field section is greater than the magnetic field strength of the first magnetic field section. As a non-limiting embodiment, the metal material of the first magnetic pole pair and the second magnetic pole pair may also be changed to change the magnetic field strength of the first magnetic field section and the second magnetic field section.

[0055] However, the above methods are not limited to the above two methods, and other methods can also be used to achieve that the absolute value of the magnetic field strength difference between the magnetic field strength corresponding to the second magnetic field segment and the magnetic field strength corresponding to the first magnetic field segment is greater than or equal to the preset magnetic field strength threshold.

[0056] Figure 3 The first schematic diagram of the magnetic field induction signal, in which the X-axis represents the different positions of the magnetic strip track, the Y-axis represents the magnitude of the magnetic field strength, and the two lines represent the sinusoidal magnetic field induction signals of the A and B phases, respectively. It can be seen from the figure that when the position is 0-6, the magnetic field strength is relatively large, which is the magnetic field segment with the larger magnetic field strength of the two magnetic field segments, and the magnetic field segment can be the first magnetic field segment or the second magnetic field segment. When the position is 6-25, the magnetic field strength is relatively small, which is the magnetic field segment with the smaller magnetic field strength of the two magnetic field segments.

[0057] When the magnetic field characteristic is the frequency of the magnetic field induction signal, since a magnetic field track may be composed of a plurality of magnetic pole pairs, the arrangement density of the magnetic pole pairs can be used to achieve that the absolute value of the difference between the magnetic field induction signal frequency corresponding to the second magnetic field segment and the magnetic field induction signal frequency corresponding to the first magnetic field segment is greater than or equal to the preset magnetic field induction signal frequency threshold. Specifically, the first magnetic field segment includes a first magnetic pole pair, the second magnetic field segment includes a second magnetic pole pair, and the arrangement density difference between the arrangement density of the first magnetic pole pair and the arrangement density of the second magnetic pole pair is greater than or equal to the preset arrangement density threshold. If the first magnetic field segment is composed of a first magnetic pole pair with a higher arrangement density, and the second magnetic field segment is composed of a second magnetic pole pair with a lower arrangement density, the magnetic field strength of the first magnetic field segment and the second magnetic field segment are the same, but the magnetic field induction signal frequency of the first magnetic field segment is greater than the magnetic field induction signal of the second magnetic field segment. Alternatively, if the first magnetic field segment is composed of first magnetic pole pairs with a lower arrangement density, and the second magnetic field segment is composed of second magnetic pole pairs with a higher arrangement density, the magnetic field strengths of the first magnetic field segment and the second magnetic field segment are the same, but the frequency of the magnetic field induction signal of the second magnetic field segment is greater than that of the magnetic field induction signal of the first magnetic field segment.

[0058] Figure 4 This is the second schematic diagram of the magnetic field induction signal, whose output angle is the A and B phase signals of the square wave. The X-axis represents the different positions of the magnetic stripe track, and the Y-axis represents the magnitude of the magnetic field strength. It can be seen from the figure that the frequency of the magnetic field induction signal in the area where the magnetic pole pairs are densely arranged is larger, and the frequency of the magnetic field induction signal in the area where the magnetic pole pairs are not densely arranged is smaller.

[0059] Figure 5 The third schematic diagram of the magnetic field induction signal, the output angle of which is the A and B phase signals of the sine wave, and Figure 5 Similarly, the frequency of the magnetic field induction signal in the area where the magnetic pole pairs are densely arranged is larger, and the frequency of the magnetic field induction signal in the area where the magnetic pole pairs are not densely arranged is smaller.

[0060] In this embodiment, when the moving part and the magnetic field detection element move on the magnetic strip track, the magnetic field detection element can detect the magnetic field at the current moving position during the movement to obtain the magnetic field sensing signal at the current moving position. For example, the magnetic field detection element can detect the magnetic field during the movement in real time; or, it can detect the magnetic field during the movement at a preset time interval; or, it can detect the magnetic field during the movement at a preset movement distance interval.

[0061] If the magnetic field detection element is a Hall element, for a position on the magnetic stripe track, the Hall element can measure the potential difference of the carriers in the direction perpendicular to the magnetic field, and determine the magnetic field induction signal at the position based on the potential difference.

[0062] However, it is not limited to the two methods described above, and other methods can also be used to achieve that the absolute value of the magnetic field induction signal frequency difference between the magnetic field induction signal frequency corresponding to the second magnetic field segment and the magnetic field induction signal frequency corresponding to the first magnetic field segment is greater than or equal to the preset magnetic field induction signal frequency threshold.

[0063] In addition, as a non-limiting example, the first magnetic field segment may be made of a first material, the second magnetic field segment may be made of a second material, and the magnetic properties of the first material are different from the magnetic properties of the first material. As an example, the first material and the second material may include Fe, Co, Ni elements and their alloys, rare earth elements and their alloys, etc. As another example, the first material or the second material may be a non-magnetic material, and the other material may be a magnetic material. By making the first magnetic field segment and the second magnetic field segment include materials with different magnetic properties, zero calibration can be performed based on the signal difference (intensity and / or frequency, etc.) between the magnetic field induction signals acquired by the magnetic field detection element at different positions on the magnetic stripe track.

[0064] S202, calibrating the encoder at zero position based on the magnetic field induction signal.

[0065] Among them, zero-position calibration refers to determining the relative position or absolute position of the zero point. Here, "zero point" represents a reference point without other special restrictions. Thus, the relative position relationship between the moving part and the zero point or other points when it is in a certain position can be determined. Exemplarily, when the encoder is disconnected and then powered on again, since the encoding value is not saved after power failure, the encoder needs to be zero-position calibrated first before the motion parameters of the moving part can be accurately obtained.

[0066] Since there are two magnetic field sections with different magnetic field characteristics in the magnetic stripe track, the magnetic field inductive signals collected by the magnetic field detection element are also different in different magnetic field sections. That is, the magnetic field induction signal corresponds to the magnetic field characteristics at different positions of the magnetic stripe track. Therefore, for example, when the encoder receives the magnetic field induction signal corresponding to the current position of the magnetic stripe track, it can compare the magnetic field induction signal at the current position with the magnetic field induction signal at the previous position. If the magnetic field induction signal at the current position is the same as the magnetic field induction signal at the previous position, the magnetic field inductive signal at the next position is continued to be obtained. If the magnetic field induction signal at the current position is different from the magnetic field induction signal at the previous position, the current position is calibrated as the zero position of the encoder. After the zero position calibration, the motion parameters of the moving part can be accurately obtained during the movement of the moving part.

[0067] Alternatively, the magnetic field induction signal may be input into a preset zero position calibration model, which analyzes the magnetic field induction signal and outputs the zero position of the encoder. The encoder is zero-calibrated according to the zero position of the encoder.

[0068] In the above-mentioned zero position calibration method of the encoder, the encoder includes a magnetic stripe track and a magnetic field detection element, the magnetic stripe track includes a first magnetic field segment and a second magnetic field segment, the magnetic field characteristics of the first magnetic field segment are different from the magnetic field characteristics of the second magnetic field segment, and the magnetic field detection element moves along the magnetic stripe track; through the magnetic field detection element, a magnetic field induction signal corresponding to the magnetic field characteristics at different positions of the magnetic stripe track is obtained; based on the magnetic field induction signal, the encoder is zero-calibrated. The method sets sections with different magnetic field characteristics on the magnetic track, so that the magnetic field induction signals detected by the magnetic field detection element in different sections are different. In this way, the magnetic field detection element measures the magnetic field induction signals at different positions on the magnetic track, and according to the magnetic field induction signal, the encoder can be accurately zero-calibrated. The whole process does not introduce other hardware equipment, reduces the random error of the encoder zero position calibration, and can improve the accuracy and reliability of the encoder zero position calibration.

[0069] Based on the above embodiments, this embodiment is to Figure 2 The relevant contents of step S202 "calibrating the encoder to zero position based on the magnetic field induction signal" are introduced and explained. Figure 6 As shown, as a non-limiting example, the above step S202 may include the following content:

[0070] S301, determining a signal difference between a magnetic field induction signal acquired at a current moment and a magnetic field induction signal acquired at a previous moment.

[0071] In this embodiment, after the encoder obtains the magnetic field sensing signal at the current moment, it can calculate the difference between the magnetic field sensing signal at the current moment and the magnetic field strength signal at the previous moment, and determine the calculated difference as the magnetic field strength signal difference between the current moment and the previous moment.

[0072] S302: If the signal difference is greater than or equal to a preset difference threshold, the position of the magnetic field detection element relative to the magnetic track at the current moment is determined as the zero position of the encoder.

[0073] In this embodiment, the encoder can compare the obtained signal difference with a preset difference threshold. If the signal difference is greater than or equal to the preset difference threshold, it is determined that the moving part switches from one magnetic field segment to another magnetic field segment. At this time, the encoder determines the position of the magnetic field detection element relative to the magnetic strip track at the current moment as the zero position of the encoder. If the signal difference is less than the preset difference threshold, it means that the moving part is still in the same magnetic field segment. At this time, the magnetic field detection element continues to obtain the magnetic field strength signal at the next moment.

[0074] In the above-mentioned zero position calibration method of the encoder, the signal difference between the magnetic field induction signal obtained at the current moment and the magnetic field strength signal obtained at the previous moment is determined; if the signal difference is greater than or equal to the preset difference threshold, the position of the magnetic field detection element relative to the magnetic stripe track at the current moment is determined as the zero position of the encoder. This method obtains the signal difference between the magnetic field induction signals at two adjacent moments, and based on the relationship between the signal difference and the preset difference threshold, accurately obtains the zero position of the encoder.

[0075] As a specific embodiment of the present application, Figure 7 As shown, the zero position calibration method of the encoder includes:

[0076] S401, obtaining magnetic field sensing signals corresponding to magnetic field characteristics at different positions of the magnetic track through a magnetic field detection element;

[0077] S402, determining a signal difference between a magnetic field induction signal acquired at a current moment and a magnetic field strength signal acquired at a previous moment;

[0078] S403: If the signal difference is greater than or equal to a preset difference threshold, the position of the magnetic field detection element relative to the magnetic track at the current moment is determined as the zero position of the encoder.

[0079] Figure 8It is a scene diagram of the encoder. In the figure, the first magnetic field segment and the second magnetic field segment form a magnetic field track. The magnetic field detection element is set at the lower position of the moving part, and the moving part can move within the range of motion in the figure. When the magnetic field detection element is a Hall element, it is matched with a drive motor and a transmission device, and the Hall principle is used to drive the moving part after the system is powered on. When the encoder detects a magnetic mutation, its rising / falling edge is passed to the processing circuit as a trigger signal, and it is marked as a zero position. The first magnetic field segment shown in the figure is set at the end position of the motion range. If the first magnetic field segment is an area with a large magnetic field intensity. There are two schemes. One is to change the magnetic field distribution of a certain interval (the first magnetic field segment) in the magnetic field track, and sense different analog signals (such as voltage) through the Hall principle of the Hall element, and then capture the jump edge of the position gain signal through analog-to-electric conversion and digital signal processing, where gain corresponds to the value of the encoding value / actual displacement. Then, the jump edge can be used as a trigger signal, and the position corresponding to this jump edge is marked as the zero position of the encoder. Another method is to change the density of the magnetic pole arrangement in a certain section (the first magnetic field section) in the magnetic field track to change the frequency of the signal induced by the Hall element, and finally capture the transition edge of the position gain signal as a trigger signal and the zero position of the encoder. In general, it is to change the magnetic field characteristics of a certain section (the first magnetic field section) in the magnetic field track, sense different analog signals through the Hall principle of the magnetic encoder, and then respond to the transition edge of the signal through analog-to-electric conversion and digital signal processing, and use it as a trigger signal as the zero position of the encoder.

[0080] When the Hall element fixedly connected to the moving part senses the magnetic field strength of the magnetic field track, the pulse digital count of the Hall element is output through the processing of the Hall linear integrated circuit and the analog-to-digital converter (ADC). The Hall element will respond to two different counting gains under the action of two different magnetic field intensities. For different moving parts, the counting gain threshold can be customized according to the operation of the Hall element of each moving part. The counting gain threshold can distinguish between the normal counting gain and the counting gain of the special point, and the integrated circuit and the processing circuit collect and process the signal of the Hall sensor in real time. When a sudden change in the gain of the Hall element is detected, the integrated circuit will detect a rising edge, and the processing circuit will latch the pulse count value at that place, use the rising edge as a trigger signal, and process the pulse count latched by the circuit as the zero position of the encoder, and then the movement of the moving part is on one side of the zero position. In the above manner, the moving part can be done multiple times under the same working condition. In order to ensure the repeatability of each trigger point of the moving part, the repeatability threshold of the multiple latched count values ​​can be defined. Only when the repeatability meets the requirements within the threshold, the zero position calibration of the encoder is completed.

[0081] Therefore, compared with the mechanical method, the method of the present application uses the electrical signal generated by the Hall effect as the stop sign of the moving parts, which can reduce the possibility of motor damage, reduce mechanical collisions, and reduce the failure rate of the system. Compared with the photoelectric method, the method of triggering the signal by the processing circuit has a smaller delay (up to μs level), reduces the random error of the system, and improves the positioning accuracy of the system.

[0082] Fig. 9 The figure is a schematic diagram of gain distribution. The X-axis represents different positions of the magnetic stripe track, and the Y-axis represents the counting gain corresponding to different positions. In one case, the magnetic field section with a larger magnetic field strength is set at the end of the motion range. When the magnetic field detection element senses two magnetic stripes with different magnetic field strengths, the modulated signal is processed by the processing circuit to form a square wave. Since the pulse amplitude corresponding to the unit magnetic pole pair length of the induced voltage change will be different, two counting gains (for example: 1 and 0.5) will be responded. If the rising edge jump threshold is set to 0.75, when the jump is detected to exceed 0.75, the magnetic field section with a larger magnetic field strength is identified, and this jump signal can be used as a trigger to mark the zero position relative to the encoder. In another case, the densely arranged magnetic pole pair area is set at the end of the motion range. After the magnetic field detection element senses the magnetic field signals generated by the magnetic pole pairs with two densely arranged degrees, after being integrated into a square wave by the processing circuit, due to the change of the induced voltage cycle, under the same magnetic field strength, the response cycle is different, and one response cycle corresponds to one magnetic pole pair length, so two counting gains (such as 1 and 0.5) will also be responded. Set the rising edge jump threshold to 0.75. When the jump is detected to exceed 0.75, it means that the densely arranged area of ​​magnetic pole pairs is identified. This jump signal can be used as a trigger to mark the zero position of the relative encoder.

[0083] It should be understood that, although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0084] Based on the same inventive concept, the embodiment of the present application also provides a zero position calibration device for an encoder for implementing the zero position calibration method of the encoder involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more zero position calibration device embodiments provided below can refer to the limitations of the zero position calibration method for the encoder above, and will not be repeated here.

[0085] In one embodiment, Fig.10 As shown, a zero position calibration device for an encoder is provided, comprising: an acquisition module 10 and a calibration module 11, wherein:

[0086] An acquisition module 10, configured to acquire magnetic field sensing signals corresponding to magnetic field characteristics at different positions of the magnetic track through the magnetic field detection element; and

[0087] Wherein, the magnetic field detection element or the magnetic strip track is fixedly coupled to the moving part whose motion parameter is to be detected;

[0088] The calibration module 11 is used to perform zero position calibration on the encoder based on the magnetic field strength signal value.

[0089] In one embodiment, an absolute value of a difference between the magnetic field characteristics of the second magnetic field segment and the magnetic field characteristics of the first magnetic field segment is greater than or equal to a preset magnetic field characteristic threshold.

[0090] In one embodiment, the magnetic field characteristic is the magnetic field intensity, the first magnetic field segment includes a first magnetic pole pair, the second magnetic field segment includes a second magnetic pole pair, the first magnetic pole pair is magnetized by a first pulse current, and the second magnetic pole pair is magnetized by a second pulse current; the current difference between the first pulse current and the second pulse current is greater than or equal to a preset current threshold.

[0091] In one embodiment, the magnetic field characteristic is the magnetic field intensity, the first magnetic field segment includes a first magnetic pole pair and the second magnetic field segment includes a second magnetic pole pair, the first magnetic pole pair and the second magnetic pole pair are made of materials with different magnetic powder densities; the magnetic powder density difference between the magnetic powder density of the material of the second magnetic pole pair and the magnetic powder density of the material of the first magnetic pole pair is greater than or equal to a preset magnetic powder density threshold.

[0092] In one embodiment, the magnetic field characteristic is the magnetic field induction signal frequency, and the difference between the magnetic field induction signal frequency corresponding to the second magnetic field segment and the magnetic field induction signal frequency corresponding to the first magnetic field segment is greater than or equal to a preset signal frequency threshold.

[0093] In one embodiment, the first magnetic field segment includes a first magnetic pole pair, the second magnetic field segment includes a second magnetic pole pair, and the arrangement density difference between the first magnetic pole pair and the second magnetic pole pair is greater than or equal to a preset arrangement density threshold.

[0094] In one embodiment, the calibration module includes: a first determination unit and a second determination unit, wherein:

[0095] A first determining unit, used to determine a signal difference between a magnetic field induction signal acquired at a current moment and a magnetic field strength signal acquired at a previous moment;

[0096] The second determination unit is used to determine the position of the magnetic field detection element relative to the magnetic stripe track at the current moment as the zero position of the encoder when the signal difference is greater than or equal to a preset difference threshold.

[0097] In one embodiment, the first magnetic field segment is made of a first material and the second magnetic field segment is made of a second material, the magnetic properties of the first material being different from the magnetic properties of the first material.

[0098] Each module in the above-mentioned zero position calibration device for encoder can be implemented in whole or in part by software, hardware and their combination. Each module can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory in the computer device in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0099] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the content of any one embodiment of the above-mentioned encoder zero position calibration method is implemented.

[0100] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the content of any one embodiment of the above-mentioned encoder zero position calibration method is implemented.

[0101] In one embodiment, a computer program product is provided, including a computer program, which, when executed by a processor, implements the content of any one of the embodiments of the above-mentioned encoder zero position calibration method.

[0102] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0103] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0104] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for zero position calibration of an encoder, characterized in that: The encoder comprises a magnetic stripe track and a magnetic field detection element, the magnetic stripe track comprises a first magnetic field segment and a second magnetic field segment, the magnetic field characteristics of the first magnetic field segment are different from the magnetic field characteristics of the second magnetic field segment, and the magnetic field detection element moves along the magnetic stripe track; The zero position calibration method comprises: Obtaining magnetic field sensing signals corresponding to magnetic field characteristics at different positions of the magnetic track through the magnetic field detection element; as well as Based on the magnetic field induction signal, the encoder is zero-calibrated.

2. The zero position calibration method according to claim 1, characterized in that: An absolute value of a magnetic field characteristic difference between the magnetic field characteristic of the second magnetic field segment and the magnetic field characteristic of the first magnetic field segment is greater than or equal to a preset magnetic field characteristic threshold.

3. The zero position calibration method according to claim 2, characterized in that: The magnetic field characteristic is magnetic field intensity, the first magnetic field section includes a first magnetic pole pair, the second magnetic field section includes a second magnetic pole pair, the first magnetic pole pair is magnetized by a first pulse current, and the second magnetic pole pair is magnetized by a second pulse current; A current difference between the first pulse current and the second pulse current is greater than or equal to a preset current threshold.

4. The zero position calibration method according to claim 2, characterized in that: The magnetic field characteristic is the magnetic field intensity, the first magnetic field segment includes a first magnetic pole pair and the second magnetic field segment includes a second magnetic pole pair, the first magnetic pole pair and the second magnetic pole pair are made of materials with different magnetic powder densities; the magnetic powder density difference between the magnetic powder density of the material of the second magnetic pole pair and the magnetic powder density of the material of the first magnetic pole pair is greater than or equal to a preset magnetic powder density threshold.

5. The zero position calibration method according to claim 2, characterized in that: The magnetic field characteristic is the frequency of the magnetic field induction signal, the first magnetic field segment includes a first magnetic pole pair, the second magnetic field segment includes a second magnetic pole pair, and the arrangement density difference between the arrangement density of the first magnetic pole pair and the arrangement density of the second magnetic pole pair is greater than or equal to a preset arrangement density threshold.

6. The zero position calibration method according to claim 1, characterized in that: The zero position calibration of the encoder based on the magnetic field induction signal includes: Determining a signal difference between a magnetic field induction signal acquired at a current moment and a magnetic field induction signal acquired at a previous moment; and If the signal difference is greater than or equal to a preset difference threshold, the position of the magnetic field detection element relative to the magnetic track at the current moment is determined as the zero position of the encoder.

7. The zero position calibration method according to claim 1, characterized in that: The magnetic field detection element or the magnetic track is fixedly coupled to the moving part whose motion parameters are to be detected.

8. The zero position calibration method according to claim 1, characterized in that: The first magnetic field segment is made of a first material and the second magnetic field segment is made of a second material, and the magnetic properties of the first material are different from the magnetic properties of the first material.

9. A zero position calibration device for an encoder, characterized in that: The encoder comprises a magnetic stripe track and a magnetic field detection element, the magnetic stripe track comprises a first magnetic field segment and a second magnetic field segment, the magnetic field characteristics of the first magnetic field segment are different from the magnetic field characteristics of the second magnetic field segment, and the magnetic field detection element moves along the magnetic stripe track; the device comprises: an acquisition module, configured to acquire, through the magnetic field detection element, magnetic field induction signals corresponding to magnetic field characteristics at different positions of the magnetic track; and A calibration module is used to perform zero position calibration on the encoder based on the magnetic field induction signal.

10. A computer-readable storage medium having instructions stored thereon, characterized in that: When the instructions are executed by a processor, the steps of the zero-position calibration method described in any one of claims 1 to 8 are implemented.

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