Incremental inductive encoder and zero signal implementation method thereof

Abstract

The application discloses an incremental inductive encoder and a zero signal implementation method thereof, and relates to the field of encoders.The encoder comprises a metal code track and a reading plate achieving relative motion with the metal code track.A plurality of grids are arranged along the direction of relative motion, and the plurality of grids are uniformly arranged at equal intervals, wherein any grid is filled with a zero part component used as a reference zero of the metal code track.The reading plate is provided with a reading component used for feeding back displacement information of the metal code track relative to the reading plate and determining the position of the zero part component.The application has the effects of facilitating the miniaturization of equipment and expanding application scenarios.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of encoders, in particular to an incremental inductive encoder and a zero signal implementation method thereof. BACKGROUND

[0002] An encoder is used to convert angular displacement or linear displacement into electrical signals through mechanical structure and signal processing circuit, so as to realize direct or indirect measurement of angular displacement, position and speed and other physical quantities. In an incremental encoder, the measurement and calculation of position must be referenced to absolute zero (for example: reference position or reference starting point in calculation), so the absolute zero of the encoder is one of the core points in the design of the incremental encoder, which affects the working performance and measurement accuracy of the incremental encoder.

[0003] At present, the zero position in the incremental encoder is usually set on one side of the incremental code channel, and a zero signal code channel is arranged on the other side. Similarly, a zero reading area corresponding to the zero signal code channel needs to be arranged outside the incremental reading area of the reading device, which increases the volume of the encoder and is not conducive to product miniaturization, thereby limiting the application scenarios. SUMMARY

[0004] In order to improve the problem of increasing the volume of the encoder caused by setting the zero signal, the present application provides an incremental inductive encoder and a zero signal implementation method thereof.

[0005] In a first aspect, the present application provides an incremental inductive encoder, which adopts the following technical solution:

[0006] An incremental inductive encoder includes a metal code channel and a reading plate that moves relative to the metal code channel. The metal code channel has a plurality of grids along the direction of relative movement, and the grids are evenly arranged at equal intervals. Any grid is filled with a zero component used as a reference zero of the metal code channel. The reading plate is provided with a reading component for feeding back the displacement information of the metal code channel relative to the reading plate and determining the position of the zero component.

[0007] By adopting the above technical solution, the reading component can feed back the position information of the metal code channel relative to the reading plate and simultaneously determine the position of the zero component during the relative movement of the metal code channel and the reading plate, so that the zero signal is realized by a single code channel, the volume of the encoder is reduced, the product miniaturization is facilitated, and the application scenarios of the encoder are expanded.

[0008] Optionally, the reading component includes an excitation coil and a receiving coil arranged on the reading plate. The excitation coil surrounds the receiving coil. The excitation coil and the receiving coil are respectively connected to a signal processing unit of the reading plate.

[0009] By adopting the technical scheme, the high-frequency alternating current is passed through the excitation coil, the metal code track generates induced current in the alternating magnetic field, and in the relative movement process of the reading plate and the metal code track, the grid arranged at intervals on the metal code track causes the amplitude of the induced voltage on the receiving coil to periodically change with the alternative displacement of the grid, and then two routes of sine and cosine signals with a certain phase difference are obtained, so that the displacement information of the metal code track relative to the reading plate can be calculated and obtained.

[0010] Optionally, the zero position component comprises a metal block filled into any grid.

[0011] By adopting the technical scheme, the metal block is filled, so that the metal area of the position is different from other positions of the metal code track, and the reading plate can determine the zero position.

[0012] In a second aspect, the application provides a zero position signal implementation method of an incremental inductive encoder

[0013] Method,

[0014] The following technical scheme is adopted:

[0015] A zero position signal implementation method of an incremental inductive encoder, the method comprises the following steps:

[0016] S1, collecting A signal and B signal output by the reading plate;

[0017] S2, performing signal processing on the A signal and the B signal to obtain A1 signal and B1 signal;

[0018] S3, calculating and obtaining the displacement information of the metal code track relative to the reading plate according to the A1 signal and the B1 signal;

[0019] S4, calculating and obtaining the signal amplitude according to the A1 signal and the B1 signal;

[0020] S5, judging whether the zero position has been detected;

[0021] If not, S6 is executed, and if yes, S1 is executed;

[0022] S6, judging whether the signal amplitude is less than a preset zero position threshold value;

[0023] If yes, the zero position is processed, and if not, S1 is returned.

[0024] Optionally, the specific method for obtaining the A1 signal and the B1 signal comprises: obtaining the A1 signal and the B1 signal after the A signal and the B signal are amplified.

[0025] Optionally, the specific method for obtaining the displacement information of the metal code track relative to the reading plate comprises: collecting the A1 signal and the B1 signal in real time through an ADC, and calculating the displacement information of the metal code track relative to the reading plate through a function relationship.

[0026] Optionally, the specific method for obtaining the displacement information of the metal code track relative to the reading plate comprises: inputting the A1 signal and the B1 signal into a comparator with a preset threshold, and detecting the high and low levels of the comparator in real time at the corresponding time, and calculating the displacement information of the metal code track relative to the reading plate through a function relationship.

[0027] Optionally, in S4, after obtaining the signal amplitude, it is judged whether the signal amplitude is valid. If not, the amplitude alarm is executed. If yes, S5 is executed.

[0028] Optionally, the specific method for judging whether the signal amplitude is valid comprises: when the obtained signal amplitude is greater than the preset maximum effective threshold or less than the preset minimum effective threshold, the signal amplitude is determined to be invalid.

[0029] Optionally, the specific method for judging whether the signal amplitude is valid comprises: when the obtained signal amplitude has a variation greater than the preset maximum variation threshold in a unit time, the signal amplitude is determined to be invalid.

[0030] In summary, the present application includes at least one of the following beneficial technical effects:

[0031] When the reading component passes through the zero component, since the metal block fills one grid of the metal code track at this time, the metal area at this position is larger than that at other positions of the metal code track. Due to the eddy current effect, the larger the metal area, the larger the area of the receiving coil shielded, and the more the magnetic field of the receiving coil dissipates, so that the amplitude of the induced voltage of the receiving coil decreases obviously when passing through the zero component, and thus it can be determined that this position is the zero reference position of the metal code track. Therefore, the determination of the zero reference position is realized on a single code track, the volume of the encoder is reduced, and the product miniaturization is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a structural schematic diagram of an encoder for measuring linear displacement in an embodiment of the present application.

[0033] Figure 2 is a structural schematic diagram of an encoder for measuring rotation angle in an embodiment of the present application.

[0034] Figure 3 is a reading plate structural schematic diagram of an encoder for measuring linear displacement in an embodiment of the present application.

[0035] Figure 4This is a flowchart of the encoder zero-position signal implementation method according to an embodiment of this application.

[0036] Figure 5 This is a logic block diagram of the encoder zero-position signal implementation method according to an embodiment of this application.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Metal code track; 2. Reading plate; 3. Grid; 4. Zero position component; 5. Reading component; 51. Excitation coil; 52. Receiving coil. Detailed Implementation

[0039] The following is in conjunction with the appendix Figures 1-5 This application will be described in further detail.

[0040] This application discloses an incremental inductive encoder. (Refer to...) Figure 1 and Figure 2 An incremental inductive encoder includes a metal code track 1 and a reading plate 2 that moves relative to the metal code track 1. The reading plate 2 is a PCB board and is parallel to the metal code track 1. The metal code track 1 can be arranged in a circular direction or in a linear extension. Therefore, the relative motion between the reading plate 2 and the metal code track 1 can be rotational or linear. The metal code track 1 has a plurality of grids 3 along the direction of relative motion. The grids 3 are evenly spaced and uniformly arranged, so that the metal code track 1 forms periodically alternating metal and non-metal regions.

[0041] Reference Figure 3 Each grid 3 is filled with a zero-position component 4, which serves as the reference zero position for the metal code track 1. The zero-position component 4 includes a metal block filled into each grid 3. The material of the metal block is the same as that of the metal code track 1, so that the metal block and the surrounding metal code track 1 form a complete metal region. The width of this metal region is N times the period of the grid 3 of the metal code track 1. The reading plate 2 is provided with a reading component 5 for feeding back the displacement information of the metal code track 1 relative to the reading plate 2 and for synchronously determining the position of the zero-position component 4. The reading component 5 corresponds to the metal code track 1. Similarly, the reading component 5 can be arranged along the circumferential direction or extended along the linear direction.

[0042] Reference Figure 3The reading component 5 comprises an excitation coil 51 and a receiving coil 52 arranged on the reading plate 2, the receiving coil 52 is wound in two loops which change periodically and in opposite directions, the excitation coil 51 is arranged around the receiving coil 52, and the excitation coil 51 and the receiving coil 52 are connected with a signal processing unit of the reading plate 2 respectively. When an alternating current is passed through the excitation coil 51, an electromagnetic field is generated around the excitation coil 51, and the metal code track 1 generates an induced current in the alternating magnetic field, the induced current on the metal code track 1 affects the change of the induced voltage on the receiving coil 52, and during the relative movement between the reading plate 2 and the metal code track 1, the amplitude of the induced voltage on the receiving coil 52 changes periodically due to the alternate displacement of the grids 3 arranged at intervals on the metal code track 1, thereby obtaining two sine and cosine signals.

[0043] With reference to Figure 3 When the reading component 5 passes through the zero component 4, since the metal block is filled in one grid 3 of the metal code track 1 at this time, the metal area at this position is larger than that at other positions of the metal code track 1, due to the eddy current effect, the larger the metal area is, the larger the area of the receiving coil 52 is shielded, and the more the magnetic field of the receiving coil 52 is dissipated, thereby the amplitude of the induced voltage of the receiving coil 52 decreases obviously when passing through the zero component 4, and the zero reference position of the metal code track 1 can be determined.

[0044] The implementation principle of the embodiment of the application is that the metal block is filled in any grid 3 of the metal code track 1, so that the metal area at this position is different from that at other positions of the metal code track 1, thereby the zero position can be determined by a single code track, the volume of the encoder is reduced, the product miniaturization is facilitated, the application scenarios of the encoder are expanded, and the metal block is filled in the rear, so that the zero position can be selected arbitrarily according to the requirement.

[0045] The embodiment of the application further discloses a zero signal implementation method of an incremental inductive encoder.

[0046] With reference to Figure 4 and Figure 5 A zero signal implementation method of an incremental inductive encoder, the method comprises the following steps:

[0047] S1, collecting A signals and B signals output by a receiving coil 52 of a reading plate 2, wherein the A signals and the B signals are sine signals and cosine signals respectively;

[0048] S2, performing signal processing on the A signals and the B signals and obtaining A1 signals and B1 signals;

[0049] Specifically, the method for obtaining the A1 signal and the B1 signal comprises the following steps: filtering and low-noise amplifier processing the sin signal and the cos signal, eliminating the noise interference, and increasing the driving capacity and the anti-interference capacity of the signal, so that the input condition of the A / D conversion is met, that is, the A1 signal and the B1 signal are obtained.

[0050] S3, according to the A1 signal and the B1 signal, the displacement information of the metal code track 1 relative to the reading plate 2 is calculated and obtained.

[0051] Specifically, the method for obtaining the displacement information of the metal code track 1 relative to the reading plate 2 comprises the following steps: collecting the A1 signal and the B1 signal in real time through the ADC, converting the analog A1 signal and the analog B1 signal into digital A1 signal and digital B1 signal, and inversely calculating the displacement information of the metal code track 1 relative to the reading plate 2 through the function relationship. When the encoder is a rotary encoder, the rotation angle value of the metal code track 1 relative to the reading plate 2 can be calculated, and when the encoder is a linear grating ruler, the linear displacement value of the metal code track 1 relative to the reading plate 2 can be calculated.

[0052] In other embodiments, the method for obtaining the displacement information of the metal code track 1 relative to the reading plate 2 can also be: inputting the A1 signal and the B1 signal into a comparator with a preset threshold, and detecting the high and low levels of the comparator in real time, and calculating the displacement information of the metal code track 1 relative to the reading plate 2 through the function relationship.

[0053] S4, according to the A1 signal and the B1 signal, the signal amplitude is calculated and determined whether the signal amplitude is valid, if not, the amplitude alarm is executed, if yes, S5 is continued to be executed.

[0054] Specifically, the A1 signal (sin signal) is squared to generate the sine voltage amplitude corresponding to the A1 signal (sin signal); the B1 signal (cos signal) is squared to generate the cosine voltage amplitude corresponding to the B1 signal (cos signal); and the sine voltage amplitude and the cosine voltage amplitude are added and squared to generate the sine-cosine voltage amplitude.

[0055] The specific method for determining whether the signal amplitude is valid comprises the following steps: first, a valid threshold range is preset, that is, there is a maximum valid threshold and a minimum valid threshold, when the obtained signal amplitude is greater than the maximum valid threshold or less than the minimum valid threshold, it means that the signal amplitude is abnormal, and the distance between the reading component 5 and the zero component 4 of the metal code track 1 may change, resulting in that the measured signal amplitude is invalid, and then an alarm is performed to warn that the metal code track 1 and the reading component 5 are abnormal and timely processing is performed to ensure the smooth determination of the zero signal position.

[0056] In other embodiments, the method of judging whether the signal amplitude is valid can also be: first preset a maximum change threshold allowed in a unit time, when the obtained signal amplitude is greater than the maximum change threshold in the unit time, then determine that the signal amplitude is invalid.

[0057] S5, judging whether the zero position has been detected, if not, executing S6, if yes, executing S1;

[0058] Specifically, after determining that the calculated signal amplitude is valid, it is judged whether the zero position has been detected before, so as to avoid repeated determination of the zero position, therefore, if the zero position has not been detected, S6 is continued to be executed, if the zero position has been detected, it returns to S1.

[0059] S6, judging whether the signal amplitude is less than a preset zero threshold, if yes, processing the zero position, if not, returning to S1.

[0060] Specifically, if the zero position has not been detected, it is judged whether the signal amplitude is less than the preset zero threshold, if yes, the position on the metal code channel 1 where the signal amplitude is generated is marked as the zero position, so as to determine the zero reference of the metal code channel 1, thereby realizing the zero signal.

[0061] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. An incremental inductive encoder characterized in that: it comprises a metal code track (1) and a reading plate (2) which realizes relative movement with the metal code track (1), the metal code track (1) is provided with a plurality of grids (3) along the direction of relative movement, and the plurality of grids (3) are uniformly arranged at equal intervals, wherein any grid (3) is filled with a zero part (4) used as a reference zero position of the metal code track (1), the zero part (4) comprises a metal block filled into any grid (3), and the reading plate (2) is provided with a reading part (5) used for feeding back displacement information of the metal code track (1) relative to the reading plate (2) and determining the position of the zero part (4). the reading part (5) comprises an excitation coil (51) and a receiving coil (52) arranged on the reading plate (2), the excitation coil (51) surrounds the receiving coil (52), and the excitation coil (51) and the receiving coil (52) are connected with a signal processing unit of the reading plate (2) respectively. After the metal block is filled, the metal area at this position is different from other positions of the metal code track, so that the reading plate can determine the zero position; when the reading part passes through the zero part, since the metal block is filled in one grid of the metal code track at this time, the metal area at this position is larger than that of other positions of the metal code track, due to the eddy current effect, the larger the metal area, the larger the area shielding the receiving coil, and the more the magnetic field of the receiving coil dissipates, so that the amplitude of the induced voltage of the receiving coil will decrease obviously when it passes through the zero part, thereby determining that this position is the zero reference position of the metal code track.

2. A zero signal implementation method of an incremental inductive encoder, applied to the incremental inductive encoder as claimed in claim 1, characterized in that: the method comprises the following steps: S1, collecting A signal and B signal output by the reading plate (2); S2, performing signal processing on the A signal and the B signal to obtain A1 signal and B1 signal; S3, obtaining displacement information of the metal code track (1) relative to the reading plate (2) according to the A1 signal and the B1 signal; S4, obtaining signal amplitude according to the A1 signal and the B1 signal; S5, judging whether the zero position has been detected; if not, executing S6, and if yes, executing S1; S6, judging whether the signal amplitude is less than a preset zero threshold value; if yes, performing zero position processing, and if not, returning to S1.

3. The zero signal implementation method of the incremental inductive encoder according to claim 2, characterized in that: the specific method for obtaining the A1 signal and the B1 signal comprises: obtaining the A1 signal and the B1 signal after the A signal and the B signal are amplified.

4. The zero signal implementation method of the incremental inductive encoder according to claim 2, characterized in that: the specific method for obtaining the displacement information of the metal code track (1) relative to the reading plate (2) comprises: collecting the A1 signal and the B1 signal in real time through an ADC, and calculating the displacement information of the metal code track (1) relative to the reading plate (2) through a function relationship.

5. The incremental inductive encoder zero position signal implementation method according to claim 2, characterized in that: The specific method for obtaining the displacement information of the metal code track (1) relative to the reading plate (2) comprises: inputting the A1 signal and the B1 signal into a comparator with a preset threshold, detecting the high and low levels of the comparator at the corresponding time in real time, and calculating the displacement information of the metal code track (1) relative to the reading plate (2) through a functional relationship.

6. The incremental inductive encoder zero position signal implementation method according to claim 2, characterized in that: In S4, after obtaining the signal amplitude, it is judged whether the signal amplitude is valid, if not, the amplitude alarm is given, and if yes, S5 is executed.

7. The incremental inductive encoder zero position signal implementation method according to claim 6, characterized in that: The specific method for judging whether the signal amplitude is valid comprises: when the obtained signal amplitude is greater than a preset maximum valid threshold or less than a preset minimum valid threshold, it is determined that the signal amplitude is invalid.

8. The incremental inductive encoder zero position signal implementation method according to claim 6, characterized in that: The specific method for judging whether the signal amplitude is valid comprises: when the obtained signal amplitude has a variation in amplitude within a unit time greater than a preset maximum variation threshold allowed within a unit time, it is determined that the signal amplitude is invalid.

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