Real-time crosstalk signal reduction system for photoelectric encoder

Abstract

The invention provides a real-time crosstalk signal reduction system for a photoelectric encoder. The device is characterized in that the device is composed of a photodiode array (1), a quaternion amplification circuit (2), a subtraction circuit (3), an attenuation circuit (4) and a coefficient adjusting system (5); wherein the photodiode array is composed of an incremental code channel photodiode array (11) and an absolute photodiode array (12), the incremental code channel photodiode array (11) is composed of each group of photodiodes, and the coefficient adjusting system (5) is composed of a potentiometer circuit (51), a peak detection circuit (52) and a comparator circuit (53). The incremental code channel photodiode array opposite to the absolute code channel is called as an array A, and the array with the phase difference of 180 degrees with the array A is called as an array B; the method can be applied to signal restoration when optical signals among code channels of the photoelectric encoder are mutually tampered, and can be widely applied to the fields of industrial production, aerospace, medical treatment, precise instruments, experimental scientific research, numerical control machine tools and the like.

Description

(I) Technical field

[0001] The present invention relates to a photoelectric encoder interference signal real-time subtraction system, which can be widely used in medical positioning, laboratories, navigation, aerospace, industrial automation, robotics, CNC machine tools and other fields, belonging to the field of photoelectric encoder technology. (II) Background technology

[0002] Photoelectric encoder is a kind of precision measuring equipment widely used in industrial automation, robotics, aerospace and other fields. Its basic principle is to emit light through a light source (such as LED), use the specific optical pattern (transparent and opaque areas) on the encoding disk or strip to modulate the light, and then the photoelectric sensor converts the optical signal into an electrical signal to achieve high-precision measurement of rotation angle or linear displacement. Photoelectric encoders are mainly divided into two types: incremental encoders and absolute encoders. Incremental encoders output relative changes in displacement and rely on displacement pulse counts to determine the position. The absolute position cannot be determined after power failure; while absolute encoders assign a unique digital code to each position, and can accurately identify the current position even in the event of power failure. This unique design makes photoelectric encoders particularly important in applications that require high precision and reliability, such as automated production lines, robotic operations, and aerospace.

[0003] With the continuous advancement of technology, the performance and functions of photoelectric encoders are also constantly improving, especially in the context of the development of optical sensors and digital signal processing technology, the resolution, accuracy and reliability of photoelectric encoders have been significantly improved. Modern photoelectric encoders have also begun to integrate a variety of communication interfaces, enhancing the connectivity and intelligent features with other devices. The future development trend of photoelectric encoders will focus on higher integration, intelligence and the application of wireless technology to meet the needs of mobile devices and complex industrial environments. At the same time, adaptability to high temperature, dusty and harsh environments will also be valued to improve its performance in challenging environments. In addition, the improvement of the human-computer interaction interface will make the operation of the encoder more intuitive and convenient, further promoting the photoelectric encoder to play a more important role in the era of intelligent manufacturing and Industry 4.0.

[0004] However, in the actual application of photoelectric encoders, due to the size of the actual code disk, the distance between each code channel is often only a few hundred microns, and the collimation of the actual light source is limited by the existing technology and cannot be fully collimated. There will still be a divergence angle, which causes the light signals of each code channel to be superimposed on each other, causing the light signals to interfere with each other. The final output signal will also be seriously distorted, which has a great impact on the actual performance of the photoelectric encoder.

[0005] In the existing technology, the method used to deal with the mutual interference of optical signals is usually to shorten the width of the code channel. However, this method further reduces the intensity of the already weak optical signal, greatly reducing the stability of the chip signal. The tolerance is extremely small, and due to process differences, there are also performance differences between light sources of the same model. When the light source intensity is too large, some crosstalk will still exist.

[0006] In order to solve these problems, the present invention proposes a new photoelectric encoder crosstalk signal subtraction system. The present invention sets a photodiode array with a specific phase difference on the incremental code channel so that the crosstalk signal appears at a fixed phase position, and then through the subtraction of the subtraction circuit, the crosstalk signal on the incremental code channel photodiode can be subtracted. After obtaining the non-interference signal of the incremental code channel, the peak-to-peak intensity of each code channel that should be initially designed is obtained, and then the signal is multiplied by the coefficient through the potentiometer circuit, and the absolute code channel (other code channels) is subtracted, and the subtraction coefficient is controlled by the comparator circuit until the crosstalk signal is completely subtracted. Through this design, real-time subtraction of the crosstalk signal of the photoelectric encoder is achieved. In addition, this method also improves the quality of the output signal, so that the photoelectric encoder can adapt to its light intensity distribution when using light sources with different performances, so that the encoder can better adapt to different application scenarios. This innovation combines advanced engineering design and optical technology, and has made significant progress in photoelectric encoders in high-precision and high-reliability photoelectric measurement. For example, in the field of aerospace, accurate position detection is crucial, and the optimized encoder can ensure the stability and safety of aircraft under complex environmental conditions. In industrial automation, with the continuous development of intelligent manufacturing, photoelectric encoders will also become an important tool for achieving efficient production. (III) Summary of the invention

[0007] The object of the present invention is to provide a real-time subtraction system for a photoelectric encoder interference signal. The system involved in the method comprises a photodiode array (1), a quartz-resistance amplifier circuit (2), a subtraction circuit (3), an attenuation circuit (4), and a coefficient adjustment system (5); wherein the photodiode array comprises an incremental code channel photodiode array (11) and an absolute code channel photodiode array (12), the incremental code channel photodiode array (11) comprises groups of photodiodes, and the coefficient adjustment system (5) comprises a potentiometer circuit (51), a peak detection circuit (52), and a comparator circuit (53); the incremental code channel photodiode array directly opposite to the absolute code channel is called an A array, and the array having a phase difference of 180° with the A array is called a B array.

[0008] The object of the present invention is achieved in that:

[0009] When the photoelectric encoder operates normally, the photodiode array (1) receives the light signal, and the incremental code channel photodiode array (1) receives the sinusoidal signal. Since the code channels are close to each other, the incremental code channel photodiode array (11) will simultaneously receive the light signal of the absolute code channel, i.e., the interference signal. The incremental code channel photodiode array (11) converts the received light signal into a photocurrent, and inputs the photocurrent into the quartz-resistance amplifier circuit (2). The A array signal and the B array signal correspond to the A signal and the B signal respectively. Then, the A signal and the B signal are input into the subtraction circuit (3), and the output signal C is obtained from AB. Since the original signals of A and B are sinusoidal signals with a phase difference of 180° plus the interference signal, and the interference signal is respectively at the top of the A signal and the bottom of the B signal, the C signal obtained after the subtraction circuit (3) is a sinusoidal signal with twice the amplitude. The C signal is input into the attenuation circuit (4) to attenuate the amplitude to half of the original amplitude. The C signal is restored to the A signal that is not interfered with, which is called the A+ signal; the signal received by the absolute photodiode array (12) is called the Z signal. The original signal of the Z signal is a pulse signal, which is interfered with by a sinusoidal signal with the same frequency as the A signal but with a smaller amplitude. The A+ signal is input into the potentiometer circuit (51), and the output signal is input into the subtraction circuit together with the Z signal to obtain the subtracted Z+ signal. The Z+ signal and the A+ signal are input into the peak detection circuit (52) to identify their peak-to-peak values, and the corresponding signal is input into the comparator circuit (53). The feedback signal is obtained by comparing the A+ and Z+ signals. When the peak-to-peak value of Z+ is greater than A+, the feedback signal is output to the potentiometer circuit (51) to increase the subtraction coefficient of A+. When A+ is equal to or less than the Z+ signal, the feedback signal is stopped. At this time, the Z signal is passed through the formula Z+=Z-coefficient*A+ in the subtraction circuit (3), and the original Z signal that is not affected by the interference signal can be obtained.

[0010] The incremental code channel photodiode array (11) is designed with a specific phase difference position so that the interference signal appears at the top of the A signal and the bottom of the B signal respectively. Since the original signals of the A and B signals are both sinusoidal signals with the same amplitude, after passing through the subtraction circuit (3), the interference signals are subtracted and canceled, and the A and B signals are subtracted to become the original signals with twice the amplitude.

[0011] The coefficient adjustment system (5) has the same design of the photodiode, so that the peak-to-peak values ​​of the A signal and the Z signal should be the same value after the crosstalk signal is excluded. After the crosstalk is removed from the A signal, the peak-to-peak value of the A+ signal is used as the reference voltage, and the peak-to-peak value of the Z+ signal is used as the comparison voltage to input the comparator voltage for comparison, thereby converting the degree of crosstalk signal removal into a comparison of the peak-to-peak values ​​of the signals, and adjusting the removal coefficient in real time through the potentiometer circuit (51).

[0012] The subtraction circuit (3) uses a specific formula and adjusts the coefficients in the formula to subtract the crosstalk problem of the photodiode output signal caused by the mutual interference of the light signals. Due to process and storage issues, there are individual differences in the light sources in actual use, and the differences are extremely large. Therefore, the coefficient for real-time subtraction of the crosstalk signal needs to be adjusted in real time according to the intensity of the actual light source and the distribution of the light signal. (IV) Description of the drawings

[0013] Figure 1 The invention discloses a structure and flow chart of a real-time subtraction system for a photoelectric encoder crosstalk signal. The real-time subtraction system for a photoelectric encoder crosstalk signal comprises a photodiode array (1), a quartz-resistance amplifier circuit (2), a subtraction circuit (3), an attenuation circuit (4), and a coefficient adjustment system (5); wherein the photodiode array comprises an incremental code channel photodiode array (11) and an absolute photodiode array (12); the incremental code channel photodiode array (11) comprises groups of photodiodes; the coefficient adjustment system (5) comprises a potentiometer circuit (51), a peak detection circuit (52), and a comparator circuit (53); the incremental code channel photodiode array directly opposite to the absolute code channel is called an A array; the array having a phase difference of 180° with the A array is called a B array; the output signal of the A array is an A signal; the output signal of the B array is a B signal; the output signal of the absolute code channel photodiode is a Z signal; the output signal of the A and B signals after passing through the subtraction circuit is a C signal; the output signal of the C signal after passing through the attenuation circuit is an A+ signal; the output signal of the Z signal and the A+ signal after passing through the subtraction circuit is a Z+ signal.

[0014] Figure 2 It is an output signal image when the output signal of the incremental code channel photodiode array (11) is disturbed, the signal affected by the interference signal at the top is the A signal, and the signal affected by the interference signal at the bottom is the B signal.

[0015] Figure 3 It is an output signal image when the output signal of the absolute photodiode array (12) is disturbed.

[0016] Figure 4 It is the actual output signal image after subtraction. The sinusoidal signal is the A+ signal and the pulse signal is the Z+ signal. (V) Specific implementation methods

[0017] Embodiment 1: Figure 1The specific structure and flow chart of the embodiment are given. The real-time subtraction system of the interference signal of the photoelectric encoder is composed of a photodiode array (1), a quartz-resistance amplifier circuit (2), a subtraction circuit (3), an attenuation circuit (4), and a coefficient adjustment system (5); wherein the photodiode array is composed of an incremental code channel photodiode array (11) and an absolute code channel photodiode array (12), the incremental code channel photodiode array (11) is composed of groups of photodiodes, and the coefficient adjustment system (5) is composed of a potentiometer circuit (51), a peak detection circuit (52) and a comparator circuit (53); the incremental code channel photodiode array directly above the absolute code channel is called the A array, and has a phase difference of 180 degrees with the A array. ° array is called B array; when the photoelectric encoder operates normally, the incremental code channel photodiode array (1) receives the sinusoidal signal. Since the distance between the code channels is relatively close, the incremental code channel photodiode array (11) will simultaneously receive the optical signal of the absolute code channel, i.e., the interference signal. The incremental code channel photodiode array (11) converts the received optical signal into a photocurrent and inputs the photocurrent to the quartz-resistance amplifier circuit (2). The A array signal and the B array signal correspond to the A signal and the B signal respectively. Then, the A signal and the B signal are input to the subtraction circuit (3). The output signal C is obtained by subtracting the B signal from the A signal. Since the original signals of A and B are sinusoidal signals with a phase difference of 180° plus the interference signal (such as Figure 2 ), and the interference signals are respectively at the top of the A signal and the bottom of the B signal. Therefore, the C signal obtained after the subtraction circuit (3) is a sinusoidal signal with twice the amplitude. The C signal is input into the attenuation circuit (4) to attenuate the amplitude to half of the original amplitude, and the C signal is restored to the A signal without interference, which is called the A+ signal. The signal received by the absolute photodiode array (12) is called the Z signal. The original signal of the Z signal is a pulse signal, which is interfered by a sinusoidal signal with the same frequency as the A signal but with a smaller amplitude (such as Figure 3 ), the A+ signal is input into the potentiometer circuit (51), the output signal is input into the subtraction circuit together with the Z signal to obtain the subtracted Z+ signal, the Z+ signal and the A+ signal are input into the peak detection circuit (52) to identify their peak-to-peak values, and the corresponding signal is input into the comparator circuit (53), and the feedback signal is obtained by comparing the A+ and Z+ signals. When the peak-to-peak value of Z+ is greater than A+, the feedback signal is output to the potentiometer circuit (51) to increase the subtraction coefficient of A+. When A+ is equal to or less than the Z+ signal, the feedback signal is stopped. At this time, the Z signal is obtained by the formula Z+=Z-coefficient*A+ in the subtraction circuit (3), and the original Z signal (such as Figure 4). Through this design, the present invention monitors the intensity of the optical signal in real time and dynamically adjusts the subtraction coefficient, effectively reducing the signal affected by the interference, and significantly improving the overall performance of the photoelectric encoder under different light source conditions; this design not only enhances the signal quality and improves the signal-to-noise ratio, but also enables the photoelectric encoder to adapt to various light intensities and light signal distributions, and is widely used in automated production, medical equipment, outdoor detection and other fields, thereby expanding its application scenarios and improving the reliability and accuracy of operation.

Claims

1. A real-time subtraction system for interference signals of photoelectric encoders. Its characteristics are: The invention is composed of a photodiode array (1), a quartz-resistance amplifier circuit (2), a subtraction circuit (3), an attenuation circuit (4), and a coefficient adjustment system (5); wherein the photodiode array is composed of an incremental code channel photodiode array (11) and an absolute code channel photodiode array (12); the incremental code channel photodiode array (11) is composed of groups of photodiodes; the coefficient adjustment system (5) is composed of a potentiometer circuit (51), a peak detection circuit (52), and a comparator circuit (53); the incremental code channel photodiode array directly above the absolute code channel is called an A array, and the array with a phase difference of 180° with the A array is called a B array; when the photoelectric encoder is operating normally, the incremental code channel photodiode array (1) receives a sinusoidal signal, and since the distance between the code channels is relatively close, the incremental code channel photodiode array (11) will At the same time, the optical signal of the absolute code channel, i.e., the crosstalk signal, is received. The incremental code channel photodiode array (11) converts the received optical signal into a photocurrent and inputs the photocurrent into the quartz-resistance amplifier circuit (2). The A array signal and the B array signal correspond to the A signal and the B signal respectively. Then, the A signal and the B signal are input into the subtraction circuit (3). The output signal C is obtained by subtracting the B signal from the A signal. Since the original signals of A and B are sinusoidal signals with a phase difference of 180° plus the crosstalk signal (as shown in FIG. 2), and the crosstalk signal is respectively at the top of the A signal and the bottom of the B signal, the C signal obtained after the subtraction circuit (3) is a sinusoidal signal with twice the amplitude. The C signal is input into the attenuation circuit (4) to attenuate the amplitude to half of the original amplitude, and the C signal is restored to the A signal without crosstalk, which is called the A+ signal. The signal received by the absolute photodiode array (12) is called a Z signal. The original signal of the Z signal is a pulse signal, which is interfered by a sinusoidal signal with the same frequency as the A signal but with a smaller amplitude. The A+ signal is input into a potentiometer circuit (51), and the output signal is input into a subtraction circuit together with the Z signal to obtain a subtracted Z+ signal. The Z+ signal and the A+ signal are input into a peak detection circuit (52) to identify their peak-to-peak values, and the corresponding signal is input into a comparator circuit (53) to obtain a feedback signal by comparing the A+ and Z+ signal sizes. When the peak-to-peak value of Z+ is greater than that of A+, the feedback signal is output to the potentiometer circuit (51) to increase the subtraction coefficient of A+. When A+ is equal to When the light intensity is greater than or less than the Z+ signal, the feedback signal is stopped from being output. At this time, the Z signal is obtained by the formula Z+=Z-coefficient*A+ in the subtraction circuit (3), and the original Z signal that is not affected by the crosstalk signal can be obtained. Through this design, the present invention monitors the light signal intensity in real time and dynamically adjusts the subtraction coefficient, effectively reducing the signal affected by the crosstalk, and significantly improving the overall performance of the photoelectric encoder under different light source conditions. This design not only enhances the signal quality and improves the signal-to-noise ratio, but also enables the photoelectric encoder to adapt to various light intensities and light signal distributions, and is widely used in fields such as automated production, medical equipment and outdoor detection, thereby expanding its application scenarios and improving the reliability and accuracy of operation.

2. The real-time subtraction system of the photoelectric encoder interference signal according to claim 1 is characterized in that: The incremental code channel photodiode array (11) is designed with a specific phase difference position so that after the A signal and the B signal are subtracted, the interference signal in the A signal can be subtracted.

3. The real-time subtraction system of the photoelectric encoder interference signal according to claim 1 is characterized in that: The coefficient adjustment system (5) converts the subtraction of the crosstalk signal into a comparison of the peak-to-peak values ​​of the signals through peak-to-peak value detection of the A+ signal and the Z+ signal and a comparator circuit, and adjusts the subtraction coefficient in real time through a potentiometer circuit (51).

4. The real-time subtraction system of the photoelectric encoder interference signal according to claim 1 is characterized in that: The subtraction circuit (3) subtracts the crosstalk problem of the photodiode output signal caused by mutual interference of optical signals through a specific formula and adjusting the coefficients in the formula.

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