Sensor and photovoltaic glass detection method adopting same

Abstract

The invention provides a sensor and a photovoltaic glass detection method using the sensor, the sensor comprises an MCU control unit, a distance measurement data processing unit, a driver, a transmitting tube, a signal amplification unit and an SPAD array optical signal receiving unit, the MCU control unit is connected with the distance measurement data processing unit, and the SPAD array optical signal receiving unit is connected with the driver. The distance measurement data processing unit is respectively connected with the driver and the signal amplification unit, the driver is connected with the transmitting tube, the signal amplification unit is connected with the SPAD array optical signal receiving unit, and the MCU control unit comprises an MCU controller; compared with the prior art, the invention has the following beneficial effects: the special chip for distance measurement and the MCU work cooperatively, the special chip for distance measurement integrates signal transmitting, receiving, processing and amplifying, and the MCU receives and records the information of the distance measurement data processing unit and calculates the depth of the photovoltaic glass and the background object in front of the sensor, thereby ensuring the stability and reliability of the product; and meanwhile, the size of the product is smaller.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic glass detection, and in particular to a sensor and a photovoltaic glass detection method using the sensor. Background Art

[0002] At present, my country's photovoltaic industry is growing at an annual rate of 30%. The related photovoltaic glass supporting production equipment urgently needs to improve its intelligence and automation capabilities to meet the rapidly growing market demand. Cost-effective photovoltaic glass detection sensor solutions have always been an urgent need of the industry.

[0003] Existing photovoltaic glass detection technologies include ordinary through-beam (transmittance) photoelectric, ordinary mirror-reflective (regressive-reflective) photoelectric and ordinary diffuse-reflective (diffuse-reflective) photoelectric; 1) When ordinary through-beam (transmittance) photoelectric or ordinary mirror-regressive (regressive-reflective) photoelectric are used to detect photovoltaic glass, the difference in light flux sensed by the photoelectric receiving end is small, which is not enough to trigger a change in the signal state, resulting in missed detection, and cannot adapt to the high light transmittance characteristics of photovoltaic glass; in engineering applications, the through-beam photoelectric sensor transmitter and receiver need to be installed on both sides of the glass, and the regression-reflective type needs to be installed outside the photoelectric sensor body, and a polarized reflector needs to be installed in the detection area, which greatly limits its practicality and cannot be implemented in some working conditions; 2) When ordinary diffuse-reflective (diffuse-reflective) photoelectric is used to detect photovoltaic glass, the light flux reflected from the transparent object to the sensor receiving end is small, which cannot reach the threshold that causes the signal state change, resulting in missed detection, and cannot adapt to the mirror reflection effect and low reflectivity of the photovoltaic glass surface;

[0004] In addition, whether it is ordinary through-beam (transmitting) photoelectric, ordinary mirror-reflective (regressive-reflective) photoelectric, or ordinary diffuse-reflective (diffuse-reflective) photoelectric, generally on a multi-layer automated conveyor line, there are high-brightness, high-reflective background objects between layers. Traditional photoelectric sensors cannot detect photovoltaic glass in a timely and accurate manner, resulting in false detection or missed detection, causing abnormal shutdown or glass impact and breakage, thereby affecting production and causing large economic losses. Summary of the invention

[0005] In view of the shortcomings of the prior art mentioned above, an object of the present invention is to provide a sensor and a photovoltaic glass detection method using the sensor, so as to solve the problem that the existing photovoltaic glass detection technology is not only unable to adapt to the high light transmittance characteristics of photovoltaic glass, but also unable to detect photovoltaic glass in a timely and accurate manner, resulting in false detection or missed detection.

[0006] To achieve the above objectives and other related objectives, the present invention provides the following technical solutions:

[0007] A sensor comprises: an MCU control unit, a ranging data processing unit, a driver, a transmitting tube, a signal amplifying unit and a SPAD array optical signal receiving unit, wherein the MCU control unit is connected to the ranging data processing unit, the ranging data processing unit is respectively connected to the driver and the signal amplifying unit, the driver is connected to the transmitting tube, and the signal amplifying unit is connected to the SPAD array optical signal receiving unit, wherein the MCU control unit comprises an MCU controller; the ranging data processing unit in the technical solution can control the transmitting tube to transmit light pulses to a detected object through the driver, the SPAD array optical signal receiving unit can receive light pulses reflected by the detected object and convert the light signals into electrical signals, the ranging data processing unit can also receive electrical signals from the signal amplifying unit, and calculate the light pulse flight time information and send it to the MCU control unit, and the MCU control unit can calculate the distance value between the sensor and the detected object according to the light pulse flight time information.

[0008] In one embodiment of the present invention, it further includes a storage unit, a key input unit and an indication unit, wherein the storage unit, the key input unit and the indication unit are all connected to the MCU control unit, and the storage unit is also connected to the ranging data processing unit.

[0009] In one embodiment of the present invention, it also includes an output unit, an output protection unit and a power supply unit for providing power to each unit of the sensor, the output unit, the output protection unit and the power supply unit are all connected to the MCU control unit, and the output unit is also connected to the output protection unit.

[0010] A photovoltaic glass detection method using the sensor, the photovoltaic glass detection method comprising the following steps: a transmitting tube on the sensor emits a light pulse toward the object to be detected, a SPAD array light signal receiving unit receives the light pulse reflected from the object to be detected and converts the light signal into an electrical signal, the electrical signal is amplified by a signal amplifying unit and then sent to a ranging data processing unit, wherein the light pulse emits N light signals within a single frame measurement time;

[0011] The ranging data processing unit receives the electrical signal from the signal amplifying unit, and calculates the light pulse flight time information according to the time of sending and receiving the light pulse, and sends the light pulse flight time information to the MCU control unit; the MCU control unit calculates the distance value between the sensor and the object to be detected according to the light pulse flight time information, and compares the distance value with the pre-set detection range value, and confirms whether the photovoltaic glass is detected according to the comparison result.

[0012] In one embodiment of the present invention, the distance value is compared with a pre-set detection range value, and whether photovoltaic glass is detected is confirmed based on the comparison result, including: judging whether the distance value between the sensor and the detected object is within the detection range value; if the distance value between the sensor and the detected object is within the detection range value, it is determined that there is photovoltaic glass within the detection range value; if the distance value between the sensor and the detected object is not within the detection range value, it is determined that there is no photovoltaic glass within the detection range value.

[0013] In one embodiment of the present invention, the transmitting tube on the sensor transmits a light pulse toward the object to be detected, the SPAD array light signal receiving unit receives the light pulse reflected from the object to be detected and converts the light signal into an electrical signal, and the electrical signal is amplified by the signal amplification unit and sent to the ranging data processing unit, and the further comprising: the transmitting tube on the sensor transmits a light pulse toward the photovoltaic glass placed at a specified detection position, the SPAD array light signal receiving unit receives the light pulse reflected from the photovoltaic glass and converts the light signal into an electrical signal, and the electrical signal is amplified by the signal amplification unit and sent to the ranging data processing unit; the ranging data processing unit receives the electrical signal from the signal amplification unit, calculates the light pulse time difference according to the time of sending the light pulse and receiving the light pulse, and sends the light pulse time difference to the MCU control unit;

[0014] The MCU control unit receives and records the light pulse time difference from the ranging data processing unit, and calculates the distance value between the sensor and the photovoltaic glass based on the light pulse time difference. The MCU control unit removes the maximum and minimum values ​​of the collected distance value and obtains the detection range value by the average filtering algorithm, and stores it in the storage unit. This technical solution can reduce the deviation of the detection range, including installation error, guide groove deviation, sensor consistency deviation, etc., by setting the detection range value before detection.

[0015] In one embodiment of the present invention, when there is a background object behind the photovoltaic glass, the MCU control unit receives and records the number of light pulses and the light pulse flight time information from the ranging data processing unit, and makes a histogram statistics of the N light pulse flight times, and filters out the background objects behind the photovoltaic glass based on the histogram statistics results and the software algorithm in the MCU control unit. This technical solution can remove the detected background objects and noise depth through the histogram statistics results and the software algorithm in the MCU control unit, and can accurately identify the photovoltaic glass.

[0016] As described above, a sensor of the present invention and a photovoltaic glass detection method using the sensor have the following beneficial effects: the present invention adopts a special chip for ranging to work in coordination with an MCU, the special chip for ranging integrates signal transmission and reception processing and amplification, the MCU receives and records information from a ranging data processing unit, and calculates the depth of the photovoltaic glass and background objects in front of the sensor, thereby ensuring the stability and reliability of the product, while also making the product smaller in size; the present invention also adopts TOF technology to measure the depth information of the target object, and performs data statistical analysis by transmitting and collecting reflected signals multiple times per unit time, thereby reducing the technical risk of missed detection; and the present invention can set the detection distance and suppress the background signal through a calibration function, thereby reducing installation errors, guide rail groove deviations, sensor consistency deviations, etc., and improving detection reliability; and the present invention performs histogram statistics on the collected light pulse flight time, and distinguishes photovoltaic glass, background objects and noise through the frequency characteristics of the statistical values, and its glass detection reliability is high and has a wide range of adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a block diagram of the overall structural unit of the sensor in the first embodiment of the present invention;

[0018] Figure 2 is a flow chart of a photovoltaic glass detection method using the sensor in a second embodiment of the present invention;

[0019] Figure 3 is a schematic diagram of using a sensor to detect photovoltaic glass in the present invention;

[0020] Figure 4 is a schematic diagram of using a sensor to detect photovoltaic glass with background objects in the present invention;

[0021] Figure 5 It is a schematic diagram of a histogram algorithm obtained according to information of T value and N value in the present invention. DETAILED DESCRIPTION

[0022] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0023] The first embodiment of the present invention relates to a sensor, for details, please refer to Figure 1, including: an MCU control unit, a ranging data processing unit, a driver, a transmitting tube, a signal amplifying unit and a SPAD array optical signal receiving unit, the MCU control unit is connected to the ranging data processing unit, the ranging data processing unit is respectively connected to the driver and the signal amplifying unit, the driver is connected to the transmitting tube, and the signal amplifying unit is connected to the SPAD array optical signal receiving unit, wherein the MCU control unit includes an MCU controller of model GD32E230;

[0024] Among them, the MCU control unit is used to receive ranging data, perform key information and data calculation processing, and control the output unit, indication unit, storage unit and output protection unit; the ranging data processing unit is used to process the ranging data and control the driver and SPAD array optical signal receiving unit at the same time; the driver is used to drive the transmitting tube; the transmitting tube is used to emit light pulses, and the transmitting tube can also emit other light sources (red light, blue light, white light, etc.); the SPAD array optical signal receiving unit is used to receive light pulses and convert the optical signal into an electrical signal; the signal amplification unit is used to amplify the electrical signal converted by the SPAD array optical signal receiving unit and transmit it to the ranging data processing unit.

[0025] It also includes a storage unit, a key input unit and an indication unit, the storage unit, the key input unit and the indication unit are all connected to the MCU control unit, and the storage unit is also connected to the ranging data processing unit; it also includes an output unit, an output protection unit and a power supply unit for providing power to each unit of the sensor, the output unit, the output protection unit and the power supply unit are all connected to the MCU control unit, and the output unit is also connected to the output protection unit;

[0026] Among them, the storage unit is used to store calibration data and operation data; the key input unit is used for product calibration and function setting, and the function setting function is distinguished by the length of time it is pressed; the function of the indication unit is as follows: the indication unit includes 2 indicator lights, one for power indication and the other for function indication; when the sensor is powered on, the power indicator light is on; after entering the short-circuit protection mode, the function indicator light flashes; in the normal working mode, the function indicator light corresponds to the output, when the output unit outputs a high level, the corresponding indicator light is on, otherwise, the function indicator light is off;

[0027] The function of the output unit is: after the compensated photovoltaic glass distance value information is calculated and judged by the MCU control unit, a digital level signal is output. The level signal controls the output tube to open or close, thereby realizing load on or off control. The output form can also be changed, such as changing the level output mode to other communication modes (wired, wireless, RS485, CAN, etc.); the function of the output protection unit is: when the current passing through the output unit exceeds the set current value, the output protection unit is triggered to generate a short-circuit signal. The MCU control unit detects the short-circuit signal, turns off the output unit, and after a delay, quickly opens the output unit again. If the short-circuit fault is eliminated, it returns to normal. Otherwise, the output unit is quickly closed again. This cycle is repeated to avoid damage to the product when the output is short-circuited.

[0028] Specifically, the photovoltaic glass runs on the conveyor belt, and the sensor is installed on a fixed bracket below the conveyor belt, about 10 cm away from the glass, and maintains a 90° vertical state with the plane of the photovoltaic glass. When the photovoltaic glass passes horizontally above the sensor with the conveyor belt, the calibrated sensor detects that the photovoltaic glass is within its set detection range, recognizes the existence of the glass, and maintains the output; when the photovoltaic glass leaves the sensor with the conveyor belt, the sensor detects that there is no object in the vertical detection area, shuts off the output, and realizes the judgment of whether the photovoltaic glass exists. For details, please refer to Figure 3 .

[0029] The second embodiment of the present invention relates to a photovoltaic glass detection method using the sensor, the process is as follows: Figure 2 As shown, the details are as follows:

[0030] Step 101, the transmitting tube on the sensor transmits a light pulse toward the object to be detected, the SPAD array optical signal receiving unit receives the light pulse reflected from the object to be detected and converts the optical signal into an electrical signal, which is amplified by the signal amplifying unit and then sent to the ranging data processing unit.

[0031] Specifically, the optical pulse will emit optical signals N times within a single frame measurement time. In this embodiment, N>50, that is, the optical pulse will emit optical signals N>50 times within a single frame measurement time.

[0032] Step 102: The ranging data processing unit receives the electrical signal from the signal amplifying unit, calculates the light pulse flight time information according to the time of sending the light pulse and receiving the light pulse, and sends the light pulse flight time information to the MCU control unit.

[0033] Step 103, the MCU control unit calculates the distance value between the sensor and the object to be detected based on the light pulse flight time information, and compares the distance value with a preset detection range value, and confirms whether the photovoltaic glass is detected based on the comparison result.

[0034] Specifically, determine whether the distance value between the sensor and the object to be detected is within the detection range value; if the distance value between the sensor and the object to be detected is within the detection range value, it is determined that there is photovoltaic glass within the detection range value; if the distance value between the sensor and the object to be detected is not within the detection range value, it is determined that there is no photovoltaic glass within the detection range value.

[0035] In practical applications, the present invention uses TOF (Time of Flight) time-of-flight ranging technology to detect the position of photovoltaic glass. The principle is as follows: a pulse wave is emitted from a light source to the object to be detected, and the SPAD array optical signal receiving unit receives the pulse wave reflected from the object to be detected, which is amplified by a signal amplification unit (OP) and then sent to a ranging data processing unit, and the time difference between the phase of the emitted light pulse and the received light pulse is calculated. Since the speed of light in the air is known, the optical path can be calculated, and then the distance between the object to be detected and the sensor can be calculated;

[0036] The specific implementation steps are as follows: the detection range value is set in the MCU controller, and when the distance value is detected to be within the range, it is confirmed that there is an object; the MCU controller controls the ranging data processing unit, and the ranging data processing unit controls the driver to drive the transmitting tube to emit light (such as: VCSEL IR), generating a modulated light pulse (the pulse will emit N>50 light signals within a single frame measurement time), and the light pulse is reflected at the object to be detected, and the SPAD array light signal receiving unit receives the light signal and converts it into an electrical signal, which is amplified by the signal amplification unit (OP) and then transmitted to the ranging data processing unit, and the ranging data processing unit calculates the flight time information T of the light pulse (N times), and transmits the T value information to the MCU controller through the IIC interface, and the MCU controller calculates the distance value based on the T value, and compares the distance value with the detection range value set in the MCU controller. If it is within the detection range value, there is photovoltaic glass, and if it is not within the detection range value, there is no photovoltaic glass.

[0037] Furthermore, before detecting the photovoltaic glass, the detection range value must first be obtained based on the photovoltaic glass. The specific steps are: the transmitting tube on the sensor emits a light pulse to the photovoltaic glass placed at the specified detection position, the SPAD array optical signal receiving unit receives the light pulse reflected from the photovoltaic glass and converts the light signal into an electrical signal, the electrical signal is amplified by the signal amplification unit and sent to the ranging data processing unit; the ranging data processing unit receives the electrical signal from the signal amplification unit, and calculates the light pulse time difference based on the time of sending the light pulse and receiving the light pulse, and sends the light pulse time difference to the MCU control unit; the MCU control unit receives and records the light pulse time difference from the ranging data processing unit, and calculates the distance value between the sensor and the photovoltaic glass based on the light pulse time difference, the MCU control unit removes the maximum and minimum values ​​of the collected distance value, and obtains the detection range value by the average filtering algorithm, and stores it in the storage unit;

[0038] The more detailed steps are as follows: the detection calibration and setting functions are realized through key input and MCU software. The photovoltaic glass is placed in the specified detection position. The MCU controller receives and records the data information from the distance measurement data processing unit. When the MCU controller recognizes the key input signal (the signal of the key being pressed for 2-5 seconds), it enters the calibration mode: the MCU controller collects the current calibration glass distance data, removes the maximum and minimum values ​​of the collected data, and then uses the average filtering algorithm to collect data and store it in the storage unit (such as EEPROM), and uses it as the action point value; after the calibration is successful, the product reads the action point value from the storage unit each time it is powered on, and the action point value is set according to the detected light. The distance value of the photovoltaic glass is compared with the stored calibrated action point value and hysteresis value (that is, the detection range value). If the distance value is less than the action point value, the MCU controller determines that the glass is in the detection area and executes the action information. If the distance value is greater than the action point value plus the set hysteresis value, the MCU controller determines that there is no detection object (glass) in the calibrated detection area and does not output it. The deviation of the detection range is reduced through calibration, including installation error, guide groove deviation, sensor consistency deviation, etc. The present invention is a detection of photovoltaic glass, so photovoltaic glass is used for calibration when calibrating the distance value. In actual applications, the present invention can also detect other objects.

[0039] Furthermore, in order to improve the production capacity of the automated production line, a multi-layer conveyor belt is usually used to transport photovoltaic glass. There is a high-brightness, high-reflective material background such as acrylic or aluminum profiles behind the photovoltaic glass. Figure 4As shown, when there is a background object behind the photovoltaic glass, especially a high reflectivity background, the reflected light energy of the background object is also strong. Ordinary photoelectric sensors cannot distinguish the reflected signals of the photovoltaic glass and the background object, and do not meet the use of this working condition. The present invention can distinguish the photovoltaic glass and background signals, and suppress noise interference, so as to achieve reliable detection of the photovoltaic glass. The specific steps are: when there is a background object behind the photovoltaic glass, the MCU control unit receives and records the number of light pulses and the light pulse flight time information from the ranging data processing unit, and makes a histogram statistics of the N light pulse flight times, and screens out the background objects behind the photovoltaic glass according to the histogram statistics results and the software algorithm in the MCU control unit;

[0040] The more detailed steps are as follows: the MCU controller receives and records the N value and T value information sent by the ranging data processing unit, and makes a histogram of the recorded N flight time T values, such as Figure 5 As shown, the reflectivity of the background object is higher than that of photovoltaic glass, and its detection depth is significantly higher than that of photovoltaic glass. The detection depth of photovoltaic glass is significantly higher than the noise depth. According to the data characteristics, the test depths of different materials are compared through signal sampling analysis, and software algorithm design is performed in the MCU controller to remove the detected background objects and noise depth, so that photovoltaic glass can be accurately identified.

[0041] In summary, the present invention adopts a dedicated ranging chip to work in collaboration with an MCU. The dedicated ranging chip integrates signal transmission and reception processing and amplification. The MCU receives and records the information of the ranging data processing unit, and calculates the depth of the photovoltaic glass and background objects in front of the sensor, thereby ensuring the stability and reliability of the product, and also making the product smaller in size; the present invention also adopts TOF technology to measure the depth information of the target object, and performs data statistical analysis by multiple transmissions and collection of reflected signals per unit time, thereby reducing the technical risk of missed detection; and the present invention can set the detection distance and suppress the background signal through the calibration function, thereby reducing installation errors, guide rail groove deviations, sensor consistency deviations, etc., and improving detection reliability; and the present invention performs histogram statistics on the collected light pulse flight time, and distinguishes photovoltaic glass, background objects and noise through the frequency characteristics of the statistical values, and its detection glass has high reliability and a wide range of adaptability.

[0042] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. All equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A sensor, Features: include: An MCU control unit, a ranging data processing unit, a driver, a transmitting tube, a signal amplifying unit and a SPAD array optical signal receiving unit, wherein the MCU control unit is connected to the ranging data processing unit, the ranging data processing unit is respectively connected to the driver and the signal amplifying unit, the driver is connected to the transmitting tube, and the signal amplifying unit is connected to the SPAD array optical signal receiving unit, wherein the MCU control unit includes an MCU controller.

2. A sensor according to claim 1, Features: It also includes a storage unit, a key input unit and an indication unit, wherein the storage unit, the key input unit and the indication unit are all connected to the MCU control unit, and the storage unit is also connected to the distance measurement data processing unit.

3. A sensor according to claim 1, Features: It also includes an output unit, an output protection unit and a power supply unit for providing power to each unit of the sensor. The output unit, the output protection unit and the power supply unit are all connected to the MCU control unit, and the output unit is also connected to the output protection unit.

4. A photovoltaic glass detection method using the sensor according to any one of claims 1 to 3, It is characterized in that The photovoltaic glass detection method comprises the following steps: The transmitting tube on the sensor emits a light pulse toward the object to be detected, and the SPAD array optical signal receiving unit receives the light pulse reflected from the object to be detected and converts the light signal into an electrical signal, which is amplified by the signal amplification unit and sent to the ranging data processing unit. The light pulse will emit N light signals within a single frame measurement time. The ranging data processing unit receives the electrical signal from the signal amplifying unit, calculates the light pulse flight time information according to the time of sending the light pulse and receiving the light pulse, and sends the light pulse flight time information to the MCU control unit; The MCU control unit calculates the distance value between the sensor and the object to be detected based on the light pulse flight time information, and compares the distance value with the pre-set detection range value, and confirms whether the photovoltaic glass is detected based on the comparison result.

5. A photovoltaic glass detection method using the sensor according to claim 4, Features: The comparing the distance value with the preset detection range value and confirming whether the photovoltaic glass is detected according to the comparison result includes: Determining whether the distance value between the sensor and the detected object is within the detection range; If the distance value between the sensor and the object to be detected is within the detection range value, it is determined that there is photovoltaic glass within the detection range value; if the distance value between the sensor and the object to be detected is not within the detection range value, it is determined that there is no photovoltaic glass within the detection range value.

6. A photovoltaic glass detection method using the sensor according to claim 4, Features: The transmitting tube on the sensor transmits a light pulse toward the object to be detected, the SPAD array light signal receiving unit receives the light pulse reflected from the object to be detected and converts the light signal into an electrical signal, and the electrical signal is amplified by the signal amplifying unit before being sent to the ranging data processing unit, and further includes: The transmitting tube on the sensor emits a light pulse to the photovoltaic glass placed at the specified detection position. The SPAD array optical signal receiving unit receives the light pulse reflected from the photovoltaic glass and converts the light signal into an electrical signal. The electrical signal is amplified by the signal amplification unit and then sent to the ranging data processing unit. The ranging data processing unit receives the electrical signal from the signal amplifying unit, calculates the light pulse time difference according to the time of sending the light pulse and receiving the light pulse, and sends the light pulse time difference to the MCU control unit; The MCU control unit receives and records the light pulse time difference from the ranging data processing unit, and calculates the distance value between the sensor and the photovoltaic glass based on the light pulse time difference. The MCU control unit removes the maximum and minimum values ​​of the collected distance value and obtains the detection range value through the average filtering algorithm, and stores it in the storage unit.

7. A photovoltaic glass detection method using the sensor according to claim 4, Features: When there is a background object behind the photovoltaic glass, the MCU control unit receives and records the number of light pulses and the light pulse flight time information from the ranging data processing unit, and makes a histogram statistics of the N light pulse flight times, and filters out the background objects behind the photovoltaic glass based on the histogram statistics results and the software algorithm in the MCU control unit.

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