Reflection type photoelectric encoder reference position calibration method

Abstract

The invention provides a reference position calibration method for a reflective photoelectric encoder. The device is characterized by comprising a coded disc (1), a photodiode array (2), a quaternion amplification circuit (3) and a position identification circuit (4). Wherein the photodiode array (2) is composed of an incremental code channel signal photodiode array (21) and a zero code channel photodiode array (22), and the position identification circuit (4) is composed of an AD conversion circuit (41), a latch circuit (42), an XOR circuit (43), a high-frequency counter circuit (44) and a digital comparison circuit (45). The method can be applied to reference position calibration of the reflective photoelectric encoder, 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

(1) Technical field

[0001] The present invention relates to a reflective photoelectric encoder reference position calibration method, which can be widely used in medical positioning, laboratories, navigation, aerospace, industrial automation, robotics, CNC machine tools and other fields. It belongs to the field of photoelectric encoder technology. (2) Background technology

[0002] Reflective photoelectric encoders are widely used sensors for position detection and motion control, operating on the principle of photoelectric conversion. These devices typically utilize optical principles to achieve high-precision position measurement and convert the results into digital signals for further processing by computers or control systems. With the development of modern industry and automation technology, the demand for high-precision position detection equipment continues to increase. Due to their superior performance, reflective photoelectric encoders have attracted widespread attention in many fields, particularly in automated production lines, robotics, aerospace, and precision manufacturing, where their application prospects are particularly broad.

[0003] The core operating principle of a reflective photoelectric encoder relies on the emission and reception of light sources. When the encoder's transmitter emits light, it is reflected by the surface of the target object and returned to the photodetector. The detector converts the reflected light into an electrical signal, which is then used to measure the target's position. The advantages of this measurement method lie in its high precision and non-contact nature, enabling the encoder to accurately locate and monitor motion without disturbing the object being measured.

[0004] However, in the actual application of reflective photoelectric encoders, the relative basic position of the photoelectric encoder chip and the code disk has a great influence on the final position settlement of the reflective photoelectric encoder. If the position offset of the photoelectric encoder chip relative to the code disk is too large, there is a probability of bit errors when calculating the actual rotation period, resulting in incorrect output position information. This is one of the key factors affecting the performance of reflective photoelectric encoders used for high-precision position settlement.

[0005] In existing technologies, most reflective photoelectric encoders generally use manual alignment and machine vision alignment. Both methods cannot accurately confirm the position of the reflective encoder relative to the code disk, and lack a simple and quick detection method for the output signal.

[0006] To address these issues, the present invention proposes a novel reference position calibration method for reflective photoelectric encoders. This optimized method utilizes a dual-code channel setup: a zero-position code channel and an incremental code channel. Photoelectric signals are converted via corresponding photodiodes. Circuitry then processes and compares the two signals, converting the reflective photoelectric encoder's position relative to the code disk into an electrical signal output to determine whether the encoder is in the reference position. This design allows for quick and easy determination of the encoder's reference position during installation. If not, the encoder can be adjusted in real time based on the provided signal. This real-time position feedback makes reflective photoelectric encoder installation more convenient, efficient, and visually intuitive. Furthermore, this method improves the output signal quality, enabling the encoder to provide stable and reliable position information under varying air gap conditions, significantly reducing the bit error rate. This innovation, combining advanced engineering design and optical technology, has significantly advanced reflective photoelectric encoders in the field of high-precision and reliable photoelectric measurement. For example, in the aerospace industry, accurate position detection is crucial. The optimized encoder can ensure the stability and safety of aircraft in complex environmental conditions. In industrial automation, with the continuous development of intelligent manufacturing, reflective photoelectric encoders will also become an important tool for achieving efficient production. (3) Summary of the invention

[0007] The present invention aims to provide a method for calibrating the reference position of a reflective photoelectric encoder. The system involved in the method comprises a code disk (1), a photodiode array (2), a quartz-resistance amplifier circuit (3), and a position recognition circuit (4). The photodiode array (2) comprises an incremental code channel signal photodiode array (21) and a zero code channel photodiode array (22), and the position recognition circuit (4) comprises an AD conversion circuit (41), a latch circuit (42), an XOR circuit (43), a high-frequency counter circuit (44), and a digital comparison circuit (45).

[0008] The object of the present invention is achieved like this:

[0009] There are two code channels on the code disk (1), namely the zero code channel and the incremental code channel. The light emitted by the reflective photoelectric encoder is reflected back to the photoelectric encoder chip through the code disk (1). The incremental code channel signal and the zero code channel signal are synchronously collected through the photodiode array (2). The two groups of signals are converted into corresponding photocurrent signals by the incremental code channel signal photodiode array (21) and the zero code channel photodiode array (22), respectively, and converted into voltage signals through the quartz-resistance amplifier circuit (3). The corresponding output signal is converted into a digital signal through the AD conversion circuit (41). The digital signal corresponding to the zero code channel is input to the latch. The detector circuit (42) performs rising edge detection. When a rising edge signal appears on the zero-position code channel, the digital signal corresponding to the zero-position code channel is input into the high-frequency counting circuit (44) for counting, and the pulse width T of a single cycle signal is calculated. At the same time, the digital signal corresponding to the incremental code channel and the digital signal corresponding to the zero-position code channel are synchronously input into the XOR circuit (43) for exclusive OR. When the reflective photoelectric encoder is in the reference position, the digital signal corresponding to the incremental code channel and the digital signal corresponding to the zero-position code channel should be square wave signals with the same amplitude and phase. After passing through the XOR circuit (43), a complete low-level signal should be output. When the position of the phase code disk of the reflective photoelectric encoder is offset to the left or right, the digital signal corresponding to the incremental code channel and the digital signal corresponding to the zero code channel will produce a phase offset, and after passing through the XOR circuit (43), a group of square wave signals are output. This group of square wave signals is input into the high-frequency counting circuit (44) for counting, and its pulse width is calculated. Then, this signal is input into the digital comparison circuit (45) for comparison with the signal corresponding to the incremental code channel after passing through the high-frequency counter circuit (44). The high level of the square wave signal after passing through the XOR circuit (43) is higher than the high level of the square wave of the incremental code channel. When the high level of the square wave signal after passing through the XOR circuit (43) does not exceed 10%, the digital comparison circuit (45) will output a high level, indicating that the position of the phase code disk of the reflective photoelectric encoder is within the tolerance range. Conversely, when the high level of the square wave signal after passing through the XOR circuit (43) does not exceed 10%, the digital comparison circuit (45) will output a low level, indicating that the position of the phase code disk of the reflective photoelectric encoder is beyond the tolerance range and the reflective photoelectric encoding position needs to be adjusted. The method can accurately calibrate the reference position of the reflective photoelectric encoder, so that the reflective photoelectric encoder is within the tolerance range when installed, effectively reducing the bit error rate of the reflective photoelectric encoder.

[0010] The zero-position code track and the incremental code track on the code disk (1) are specially designed in position. The zero-position code track is located on one side of the incremental code track. The code track size is the same as the incremental code track size. The position is set according to the position of the photodiode on the photoelectric encoder, so that the two groups of signals received by the reflective encoder at the reference position are in phase.

[0011] The method converts the position signal of the reflective photoelectric encoder relative to the code disk into the phase relationship between the signal corresponding to the incremental code channel and the signal corresponding to the zero code channel, counts the high level area of the zero code channel through a high-level counting circuit (44), and uses it as the time of a single cycle. Finally, the signal compared in the XOR (43) circuit is digitally compared with the signal corresponding to the zero code channel, converts the position information into the phase difference between the two groups of signals, and compares it with a preset tolerance value. Finally, the position state signal is output, with a high level indicating an aligned state and a low level indicating a misaligned state.

[0012] In the method, when the signal after passing through the XOR circuit (43) is compared with the signal corresponding to the zero code channel, the set tolerance value can be set according to the tolerance range set by the actual reflective photoelectric encoder, and can also be set according to the precision of the actual use scenario. (IV) Description of the accompanying drawings

[0013] Figure 1 The invention is composed of a code disk (1), a photodiode array (2), a quartz-resistance amplifier circuit (3), and a position identification circuit (4). The photodiode array (2) is composed of an incremental code channel signal photodiode array (21) and a zero code channel photodiode array (22), and the position identification circuit (4) is composed of an AD conversion circuit (41), a latch circuit (42), an XOR circuit (43), a high-frequency counter circuit (44), and a digital comparison circuit (45).

[0014] Figure 2 It is the phase and frequency distribution of the zero-position code channel corresponding signal and the incremental code channel corresponding signal at the reference position in the reflective photoelectric encoder example. The incremental code channel signal is a periodic square wave signal, and the zero-position signal is a square wave signal that appears at a specific position. At the reference position, the rising edge of the zero-position signal is consistent with the rising edge of the incremental code channel.

[0015] Figure 3 It is the signal output by the XOR circuit (43) when the reflective photoelectric encoder is at the reference position. Since it is at the reference position, it is a completely low-level signal after passing through the XOR circuit (43).

[0016] Figure 4 It is the signal output by the XOR circuit (43) at the offset position and the zero position signal in the reflective photoelectric encoder example. (V) Specific implementation methods

[0017] Example 1: Figure 1An embodiment of a reference position calibration method for a reflective photoelectric encoder is provided. The reference position calibration method for a reflective photoelectric encoder comprises a code disk (1), a photodiode array (2), a quartz-resistance amplifier circuit (3), and a position recognition circuit (4).The photodiode array (2) is composed of an incremental code channel signal photodiode array (21) and a zero code channel photodiode array (22); the position identification circuit (3) is composed of an AD conversion circuit (41), a latch circuit (42), an XOR circuit (43), a high-frequency counter circuit (44) and a digital comparison circuit (45); the code disk (1) has two code channels, namely, a zero code channel and an incremental code channel; the light emitted by the reflective photoelectric encoder is reflected back to the photoelectric encoder chip via the code disk (1); the incremental code channel signal and the zero code channel signal are synchronously collected by the photodiode array (2); the two groups of signals are respectively detected by the incremental code channel signal photodiode array (21) and the zero code channel photodiode array. The column (22) is converted into a corresponding photocurrent signal, and then converted into a voltage signal through a quartz-resistance amplifier circuit (3). The corresponding output signal is converted into a digital signal through an AD conversion circuit (41). The digital signal corresponding to the zero-position code channel is input to a latch circuit (42) for rising edge detection. When a rising edge signal appears on the zero-position code channel, the digital signal corresponding to the zero-position code channel is input to a high-frequency counting circuit (44) for counting, and the pulse width T of a single cycle signal is calculated. At the same time, the digital signal corresponding to the incremental code channel and the digital signal corresponding to the zero-position code channel are synchronously input to an XOR circuit (43) for exclusive OR. When the reflective photoelectric encoder is in the reference position, the digital signal corresponding to the incremental code channel and the zero-position code channel are input to an XOR circuit (43) for exclusive OR. The digital signal corresponding to the channel should be a square wave signal with the same amplitude and phase, as shown in Figure (2). After passing through the XOR circuit (43), a completely low-level signal should be output, as shown in Figure (3). When the position of the phase code disk of the reflective photoelectric encoder is offset left and right, the digital signal corresponding to the incremental code channel and the digital signal corresponding to the zero code channel will produce a phase offset. After passing through the XOR circuit (43), a group of square wave signals are output. This group of square wave signals is input into the high-frequency counting circuit (44) for counting and calculating its pulse width. Then, the signal is input into the digital comparison circuit (45) for comparison with the signal corresponding to the incremental code channel after passing through the high-frequency counter circuit (44), as shown in Figure (4). After passing through the XOR circuit (43), the digital signal corresponding to the incremental code channel and the zero code channel will be output. The high level of the square wave signal after the XOR circuit (43) is compared with the high level of the square wave of the corresponding signal of the incremental code channel. When the high level of the square wave signal after the XOR circuit (43) does not exceed 10%, the digital comparison circuit (45) will output a high level, indicating that the position of the phase code disk of the reflective photoelectric encoder is within the tolerance range. On the contrary, when the high level is higher than 10%, the digital comparison circuit (45) will output a low level, indicating that the position of the phase code disk of the reflective photoelectric encoder is beyond the tolerance range and the reflective photoelectric encoding position needs to be adjusted. The method can accurately calibrate the reference position of the reflective photoelectric encoder so that the reflective photoelectric encoder is within the tolerance range when installed, effectively reducing the bit error rate of the reflective photoelectric encoder.

Claims

1. A method for calibrating the reference position of a reflective photoelectric encoder. The method is characterized by: The invention comprises a code disk (1), a photodiode array (2), a quartz-resistance amplifier circuit (3), and a position identification circuit (4). The photodiode array (2) comprises an incremental code channel signal photodiode array (21) and a zero code channel photodiode array (22), and the position identification circuit (4) comprises an AD conversion circuit (41), a latch circuit (42), an XOR circuit (43), a high-frequency counter circuit (44), and a digital comparison circuit (45). The code disk (1) has two code channels, namely, a zero code channel and an incremental code channel. The light emitted by the reflective photoelectric encoder is reflected back to the photoelectric encoder chip through the code disk (1), and the incremental code channel signal and the zero code channel signal are synchronously collected by the photodiode array (2). The two groups of signals are respectively detected by the incremental code channel signal photodiode array (21) and the zero code channel light. The photodiode array (22) is converted into a corresponding photocurrent signal, and then converted into a voltage signal through a quartz-resistance amplifier circuit (3). The corresponding output signal is converted into a digital signal through an AD conversion circuit (41). The digital signal corresponding to the zero-position code channel is input to a latch circuit (42) for rising edge detection. When a rising edge signal appears on the zero-position code channel, the digital signal corresponding to the zero-position code channel is input to a high-frequency counting circuit (44) for counting, and the pulse width T of a single cycle signal is calculated. At the same time, the digital signal corresponding to the incremental code channel and the digital signal corresponding to the zero-position code channel are synchronously input to an XOR circuit (43) for exclusive OR. When the reflective photoelectric encoder is in the reference position, the digital signal corresponding to the incremental code channel is input to a latch circuit (42) for rising edge detection. The digital signal and the digital signal corresponding to the zero-position code channel should be square wave signals with the same amplitude and phase, and should output a completely low-level signal after passing through the XOR circuit (43); when the position of the phase code disk of the reflective photoelectric encoder is offset left and right, the digital signal corresponding to the incremental code channel and the digital signal corresponding to the zero-position code channel will produce a phase offset, and after passing through the XOR circuit (43), a group of square wave signals are output. This group of square wave signals is input into the high-frequency counting circuit (44) for counting, and its pulse width is calculated. Then, this signal is input into the digital comparison circuit (45) for comparison with the signal corresponding to the incremental code channel after passing through the high-frequency counter circuit (44), and the signal after passing through the XOR circuit (4 3) The high level of the square wave signal after the XOR circuit (43) is compared with the high level of the square wave of the corresponding signal of the incremental code channel. When the high level of the square wave signal after the XOR circuit (43) does not exceed 10%, the digital comparison circuit (45) will output a high level, indicating that the position of the phase code disk of the reflective photoelectric encoder is within the tolerance range. On the contrary, when the high level is higher than 10%, the digital comparison circuit (45) will output a low level, indicating that the position of the phase code disk of the reflective photoelectric encoder is beyond the tolerance range and the reflective photoelectric encoding position needs to be adjusted. The method can accurately calibrate the reference position of the reflective photoelectric encoder, so that the reflective photoelectric encoder is within the tolerance range when installed, effectively reducing the bit error rate of the reflective photoelectric encoder.

2. The method for calibrating the reference position of a reflective photoelectric encoder according to claim 1, wherein: The zero-position code track and the incremental code track on the code disk (1) are specially designed in position, so that the two groups of signals received by the reflective encoder at the reference position are in phase.

3. The method for calibrating the reference position of a reflective photoelectric encoder according to claim 1, wherein: The method converts the position signal of the reflective photoelectric encoder relative to the code disk into the phase difference between the zero-position code channel signal and the incremental code channel signal, and performs quantitative comparison through a high-frequency counting circuit (44) and a digital comparison circuit (45).

4. The method for calibrating the reference position of a reflective photoelectric encoder according to claim 1, wherein: In the method, when the signal after passing through the XOR circuit (43) is compared with the signal corresponding to the zero code channel, the deviation percentage can be adjusted, which is related to the setting tolerance of the reflective photoelectric encoder.

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