Photoelectric speed measurement sensor response threshold measuring device and measuring method thereof

Abstract

The invention relates to a photoelectric type speed measurement sensor response threshold measuring device and a measuring method thereof.The measuring device comprises a plurality of guide rails arranged on a base, one guide rail is provided with an adjusting and positioning module of a photoelectric type speed measurement sensor, the other two guide rails are distance comb moving guide rails, and a traction motor drives a distance comb to the high position and then releases the distance comb; the data acquisition card acquires voltage signals when the distance comb falls and passes through the photoelectric speed measurement sensor, transmits the voltage signals to the data processor for processing and storage, extracts time point inflection points corresponding to tooth gaps between the last tooth and the last adjacent two teeth of the distance comb respectively, and calculates a voltage average value of the two adjacent time point inflection points; and sequentially extracting the time point when each section of data passes through the threshold voltage, calculating the relative deviation between the actual time ratio and the theoretical time ratio until the measured relative deviation accords with the allowable relative deviation, and determining the threshold voltage. The method can accurately confirm the threshold value of the photoelectric speed measurement sensor, reduces the measurement error, and guarantees the test quality.

Description

Technical Field

[0001] The present invention relates to a device for sensor performance confirmation, and particularly discloses an optoelectronic speed measurement sensor response threshold determination device and a determination method thereof, which are applied to the metrology and testing industry for calibrating optoelectronic speed measurement sensors. Background Art

[0002] Optoelectronic speed measurement sensors are widely used in the measurement of instantaneous speed in object motion, impact, and collision tests. In these tests, the measurement result of instantaneous speed reflects the specific state of the object, and the accuracy of the measurement result will determine the quality of the test. Therefore, the accuracy of the optoelectronic speed measurement sensor itself must be confirmed to determine whether it meets the test requirements. However, at present, the threshold voltage between the unobstructed and blocked state transitions of the optoelectronic speed measurement sensor cannot be confirmed, resulting in possible errors in the confirmation time of the threshold voltage.

[0003] When there is an obstruction between the receiver and the transmitter during the use of the optoelectronic speed measurement sensor, the output state of the optoelectronic speed measurement sensor will switch between N (negative) and P (positive). Ideally, there is no time difference in this switch, but in reality, it is impossible to achieve no time difference. The ideal voltage signal and the actual voltage signal are as Figure 1 shown. In the figure, the solid line is the ideal voltage signal output curve, and the dashed line is the actual voltage signal output curve.

[0004] The voltages corresponding to the output states N and P of the optoelectronic speed measurement sensor are U N and U P . In an ideal situation, the threshold voltage is between U N and U P , and the time taken to pass through the threshold voltage twice is the same. However, for the actual situation, when the threshold voltage varies between U N and U P , the closer the threshold voltage is to U N , the longer the time; the closer the threshold voltage is to U P , the shorter the time. This difference in duration will cause errors in the measurement results. In the actual signal, as the threshold voltage changes from U N to U P , the duration corresponding to the threshold voltage monotonically decreases from greater than the ideal duration to less than the ideal duration. There exists and only exists a unique threshold voltage such that the actual duration matches the ideal duration. To ensure the accuracy of the measurement results, it is necessary to find the threshold voltage of the optoelectronic speed measurement sensor so that the actual duration matches the ideal duration. Summary of the Invention

[0005] The object of the present invention is to solve the problem that there is no threshold confirmation for optoelectronic speed sensors in the prior art, and to design a device and method for measuring the response threshold of an optoelectronic speed sensor, so as to reduce the measurement error during use and ensure the test quality.

[0006] The present invention is implemented as follows: A device and method for measuring the response threshold of an optoelectronic speed sensor. The device for measuring the response threshold of the optoelectronic speed sensor includes a base, a left guide rail, a front guide rail, and a right guide rail provided on the base. An adjustment and positioning module for the optoelectronic speed sensor is provided on the front guide rail. The left guide rail and the right guide rail pass through through holes provided at both ends of a distance comb fixing module. A distance comb is fixed on the distance comb fixing module. The size and spacing of each tooth of the distance comb are the same. The distance comb fixing module is also provided with a traction fixing hole connected to the traction motor cable, and the distance comb fixing module and the distance comb are driven by the traction motor to move upward along the left guide rail and the right guide rail.

[0007] The adjustment and positioning module includes a coarse adjustment positioning module and a fine adjustment positioning module. The coarse adjustment positioning module is fixed in relative position with the front guide rail through a locking nut. The fine adjustment positioning module is fixed above the coarse adjustment positioning module, and the optoelectronic speed sensor is fixed above the fine adjustment positioning module.

[0008] The traction motor is connected to the traction fixing hole through a cable via a pulley. A top cover is provided at the top of the left guide rail, the front guide rail, and the right guide rail, and the pulley for connecting the traction motor cable is provided on the lower surface of the top cover.

[0009] The central axis of the pulley coincides with the central axis of the traction fixing hole provided on the distance comb fixing module.

[0010] The left guide rail, the front guide rail, and the right guide rail are respectively provided on the left, front, and right sides of the base, and the distances between the front guide rail and the left guide rail and between the front guide rail and the right guide rail are equal.

[0011] The method for measuring the response threshold of the optoelectronic speed sensor uses the above-mentioned device for measuring the response threshold of the optoelectronic speed sensor, and the specific measurement steps are as follows: S1. The distance comb fixing module fixed with the distance comb is stretched upward to the top of the two guide rails by the traction force of the traction motor.

[0012] S2. Adjust the adjustment and positioning module of the optoelectronic speed sensor to make the optoelectronic speed sensor approach the lower part of the distance comb and make the optoelectronic speed sensor in the state switching mode.

[0013] In step S2, the lower part of the proximity comb of the optoelectronic speed sensor is adjusted by the coarse positioning module in the positioning module, and the optoelectronic speed sensor is in the state switching mode by adjusting the fine positioning module in the positioning module.

[0014] S3. The traction motor is quickly released, and the proximity comb fixing module with the proximity comb fixed on it falls along the two guide rails. When it passes through the optoelectronic speed sensor during the fall, the data acquisition card collects the signal U of the optoelectronic speed sensor and transmits it to the data processor. The data processor generates an actual voltage signal output curve and performs data processing and storage.

[0015] In step S3, the entire falling process of the proximity comb is a constant acceleration process. Since the size of each tooth of the proximity comb and the spacing between the teeth are the same, the ideal time interval is T, T, T, T... and so on. Assuming that the number of teeth of the proximity comb of the optoelectronic speed sensor is n (n>1), there are 2n - 1 time points.

[0016] S4. Respectively extract the time point inflection points t1, t2, t3, t4, t5, t6 corresponding to the last tooth of the proximity comb (hereinafter referred to as the last tooth) and the tooth gap between the last two adjacent teeth of the proximity comb (hereinafter referred to as the last tooth gap) in the signal U.

[0017] S5. Take the data in the t5 - t4 section of the signal U to calculate the average voltage and set it as U T , take the data in the t3 - t2 section of the signal U to calculate the average voltage and set it as U D .

[0018] S6. Calculate using the bisection method, set the threshold voltage , where m is the number of measurements, and successively take natural numbers of 1, 2, 3... m. Successively extract the time points when the data in the t6 - t5, t4 - t3, and t2 - t1 sections of the voltage U cross the threshold voltage V m . Respectively T1, T2, T3. Calculate (T3 - T2) / (T2 - T1) to obtain the actual time ratio of the optoelectronic speed sensor passing through the last tooth and the last tooth gap, and compare it with the theoretical time ratio of the optoelectronic speed sensor passing through the last tooth and the last tooth gap. Finally, obtain the relative deviation e. If the relative deviation e is less than or equal to the allowable relative deviation of the optoelectronic speed sensor, the threshold voltage of the optoelectronic speed sensor can be determined as V m .

[0019] When the relative deviation e obtained in step S6 is greater than the allowable relative deviation of the optoelectronic speed sensor, there are the following two situations: At the ratio of (T3 - T2) / (T2 - T1) When it is larger, take U T = V m , U D = U D ; At the ratio of (T3 - T2) / (T2 - T1) When it is smaller, take U T = U T , U D = V m , Then repeat step S6 until the relative deviation e is less than or equal to the allowable relative deviation, and determine the threshold voltage of the optoelectronic speed measurement sensor as V m .

[0020] The beneficial effects of the present invention are as follows: The application principle of the present invention is simple and easy to understand, the preparation cost of the measuring device is low, the structure assembly is convenient and fast, it is suitable for the production manufacturers, users and detection structures of optoelectronic sensors, the measurement result is accurate, it can effectively detect the effectiveness of optoelectronic sensors, and it can improve the measurement accuracy of the pulse width during the use of optoelectronic sensors. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the ideal signal and actual signal output curves of the optoelectronic speed measurement sensor.

[0022] Figure 2 It is a schematic diagram of the working state structure of the optoelectronic speed measurement sensor response threshold determination device of the present invention.

[0023] Figure 3 It is a graph of the actual voltage signal output.

[0024] In the figure: 1. Base; 2. Left guide rail; 3. Front guide rail; 4. Right guide rail; 5. Coarse adjustment positioning module; 6. Coarse adjustment positioning module locking nut; 7. Fine adjustment positioning module; 8. Optoelectronic speed measurement sensor; 9. Distance comb fixing module; 10. Distance comb. Specific Embodiments

[0025] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0026] According to the appendix Figure 2, the present invention is an apparatus and method for measuring the response threshold of an optoelectronic speed sensor. The apparatus for measuring the response threshold of the optoelectronic speed sensor includes a base 1, a left guide rail 2, a front guide rail 3, and a right guide rail 4 disposed on the base 1. A coarse adjustment positioning module 5 of the optoelectronic speed sensor is provided on the front guide rail 3 and is fixed in relative position with the front guide rail 3 through a locking nut 6. A fine adjustment positioning module 7 is fixed above the coarse adjustment positioning module 5, and the optoelectronic speed sensor 8 is fixed above the fine adjustment positioning module 7. The left guide rail 2 and the right guide rail 4 pass through through holes provided at both ends of a distance comb fixing module 9. A distance comb 10 is fixed on the distance comb fixing module 9. The size of each tooth of the distance comb 10 and the spacing between the teeth are the same. The distance comb fixing module 9 is further provided with a traction fixing hole, and a traction motor is connected to the traction fixing hole through a cable via a pulley. The distance comb fixing module 9 and the distance comb 10 are driven by the traction motor to move upward along the left guide rail 2 and the right guide rail 4. A top cover 11 is provided at the top of the left guide rail 2, the front guide rail 3, and the right guide rail 4. The pulley for connecting the cable of the traction motor is disposed on the lower surface of the top cover 11, and the central axis of the pulley coincides with the central axis of the traction fixing hole provided on the distance comb fixing module 9.

[0027] To keep the measuring device stable, the left guide rail 2, the front guide rail 3, and the right guide rail 4 are respectively disposed at the left, front, and right sides of the base 1, and the distance between the front guide rail 3 and the left guide rail 2 and the right guide rail 4 is equal.

[0028] The method for measuring the response threshold of the optoelectronic speed sensor uses the above-mentioned apparatus for measuring the response threshold of the optoelectronic speed sensor, and the specific steps are as follows: S1. The distance comb fixing module 9 fixed with the distance comb 10 is stretched upward by the traction force of the traction motor. Since the top cover 11 is provided in this embodiment, it is until the top of the distance comb 10 contacts the top cover 11.

[0029] S2. Lock the locking nut 6 of the coarse adjustment positioning module, and move the coarse adjustment positioning module 5 to make the optoelectronic speed sensor 8 approach the lower part of the distance comb 10.

[0030] S3. Adjust the fine adjustment positioning module 7 to make the optoelectronic speed sensor 8 in the state switching mode.

[0031] S4. The traction motor is quickly released, and the distance comb fixing module 9 with the distance comb 10 fixed on it drops along the two guide rails. When it passes through the photoelectric speed sensor 8 during the drop, the output signal of the photoelectric speed sensor 8 changes. The data acquisition card collects the signal U of the photoelectric speed sensor 8 and transmits it to the data processor. The data processor generates the actual voltage signal output curve and performs data processing and storage. The entire dropping process can be considered a constant acceleration process. Since the distance between each tooth and the tooth gap of the distance comb of each photoelectric speed sensor is the same, the ideal time interval should be T, T, T, T... and so on.

[0032] Suppose the number of teeth of the distance comb of the photoelectric speed sensor is n (n>1), then there are 2n - 1 time points. The theoretical times for the photoelectric speed sensor to pass through the last tooth and the last tooth gap are respectively and . The allowable relative deviation of the actual time ratio to the theoretical time ratio for passing through the last tooth and the last tooth gap is set as E.

[0033] S5. According to Appendix Figure 3 , respectively extract the time point inflection points t1, t2, t3, t4, t5, t6 corresponding to the last tooth and the last tooth gap; S6. Take the data in the t5 - t4 section of the signal U to calculate the average voltage and set it as U T , take the data in the t3 - t2 section of the signal U to calculate the average voltage and set it as U D .

[0034] S7. Use the bisection method to calculate, set the threshold voltage , where m is the number of measurements, successively take natural numbers 1, 2, 3... m, and successively extract the time points when the data in the t6 - t5, t4 - t3, t2 - t1 sections of the voltage U cross the threshold voltage V m , which are T1, T2, T3 respectively. Calculate (T3 - T2) / (T2 - T1) to obtain the actual time ratio of the photoelectric speed sensor passing through the last tooth and the last tooth gap, and compare it with the theoretical time ratio of the photoelectric speed sensor passing through the last tooth and the last tooth gap. Finally, obtain the relative deviation e. If the relative deviation e is not greater than the allowable relative deviation E, it meets the requirements. V m is the threshold voltage of the photoelectric speed sensor.

[0035] If the relative deviation e does not meet the requirements, when (T3 - T2) / (T2 - T1) is larger than , take U T = V m, U D = U D ; At the ratio of (T3 - T2) / (T2 - T1) hours, take U T = U T , U D = V m , Then continue to repeat step S7 until the relative deviation e meets the requirements, and determine the threshold voltage V of the optoelectronic speed measurement sensor m。

Claims

1. A method for determining a response threshold of a photoelectric speed sensor, characterized in that: The measuring method adopts a photoelectric speed sensor response threshold measuring device, which includes a base and a left guide rail, a front guide rail and a right guide rail arranged on the base. The front guide rail is provided with an adjustment and positioning module of the photoelectric speed sensor. The left guide rail and the right guide rail are used to position a distance comb fixing module. A distance comb is fixed on the distance comb fixing module. The size of each comb tooth of the distance comb and the spacing between the comb teeth are consistent. The traction motor drives the distance comb fixing module and the distance comb to move upward along the left guide rail and the right guide rail through the fixing holes arranged on the distance comb fixing module. The specific steps of the assay method are as follows: S1, the distance comb fixing module with the distance comb fixed thereon is stretched upward to the top of the two guide rails through the traction force of the traction motor, S2, adjust the adjustment and positioning module of the photoelectric speed sensor, so that the photoelectric speed sensor is close to the lower part of the distance comb, and the photoelectric speed sensor is in the state switching mode, S3, the traction motor is quickly released, and the distance comb fixing module with the distance comb fixed falls along the two guide rails. When falling through the photoelectric speed sensor, the data acquisition card collects the signal U of the photoelectric speed sensor and transmits it to the data processor. The data processor generates the actual voltage signal output curve, and processes and saves the data. S4, respectively extract the time inflection points t1, t2, t3, t4, t5, and t6 corresponding to the last tooth of the distance comb and the tooth gap between the last two adjacent teeth of the distance comb in the signal U; S5, take the data from t5 to t4 in signal U and calculate the voltage average value and set it as U T , take the data from t3 to t2 in signal U and calculate the voltage average value as U D , S6, use binary calculation to set the threshold voltage , where m is the number of measurements, and the natural numbers 1, 2, 3, ... m are taken in turn to extract the data crossing the threshold voltage V from t6 to t5, t4 to t3, and t2 to t1 in the voltage U. m The time points are T1, T2, and T3 respectively. Calculate (T3-T2) / (T2-T1) to obtain the actual time ratio of the photoelectric speed sensor passing through the last tooth of the distance comb and the gap between the last two adjacent teeth of the distance comb, and the theoretical time ratio of the photoelectric speed sensor passing through the last tooth of the distance comb and the gap between the last two adjacent teeth of the distance comb. By comparison, the relative deviation e is obtained. The relative deviation e is less than or equal to the allowable relative deviation of the photoelectric speed sensor. The threshold voltage of the photoelectric speed sensor is determined to be V m .

2. The method for determining the response threshold of a photoelectric speed sensor according to claim 1, characterized in that: In step S2, the photoelectric speed sensor is adjusted to be close to the lower part of the distance comb by adjusting the coarse adjustment positioning module in the positioning module, and the photoelectric speed sensor is placed in the state switching mode by adjusting the fine adjustment positioning module in the positioning module.

3. The method for determining the response threshold of a photoelectric speed sensor according to claim 1, characterized in that: The entire falling process of the distance comb in step S3 is a constant acceleration process. Since the size of each tooth of the distance comb and the spacing between the teeth are consistent, the ideal time interval is T. T. T. T..., assuming that the number of teeth of the photoelectric speed sensor distance comb is n, where n>1, then there are 2n-1 time points, and so on.

4. The method for determining the response threshold of a photoelectric speed sensor according to claim 1, characterized in that: The relative deviation e obtained in step S6 is greater than the allowable relative deviation of the photoelectric speed sensor. In (T3-T2) / (T2-T1) ratio When large, take U T =V m , U D =U D ; In (T3-T2) / (T2-T1) ratio Hours, take U T =U T , U D =V m , Then repeat step S6 until the relative deviation e is less than or equal to the allowable relative deviation, and determine the threshold voltage of the photoelectric speed sensor to be V m .

5. A device for measuring the response threshold of a photoelectric speed sensor, used in the method for measuring the response threshold of a photoelectric speed sensor as claimed in any one of claims 1 to 4, characterized in that: The measuring device includes a base and a left guide rail, a front guide rail and a right guide rail arranged on the base. The front guide rail is provided with an adjustment and positioning module of a photoelectric speed sensor. The left guide rail and the right guide rail pass through through holes set at both ends of the distance comb fixing module. A distance comb is fixed on the distance comb fixing module. The size of each comb tooth of the distance comb and the spacing between the comb teeth are consistent. The distance comb fixing module is also provided with a traction fixing hole connected to the traction motor cable. The traction motor drives the distance comb fixing module and the distance comb to move upward along the left guide rail and the right guide rail.

6. The device for determining the response threshold of a photoelectric speed sensor according to claim 5, characterized in that: The adjustment and positioning module includes a coarse adjustment positioning module and a fine adjustment positioning module. The coarse adjustment positioning module is fixed relative to the front guide rail through a locking nut. The fine adjustment positioning module is fixed above the coarse adjustment positioning module, and the photoelectric speed sensor is fixed above the fine adjustment positioning module.

7. The device for determining the response threshold of a photoelectric speed sensor according to claim 5, characterized in that: The traction motor is connected to the traction fixing hole through a cable via a pulley. A top cover is provided on the top of the left guide rail, the front guide rail and the right guide rail. A pulley for connecting the traction motor cable is provided on the lower surface of the top cover.

8. The device for determining the response threshold of a photoelectric speed sensor according to claim 7, characterized in that: The central axis of the pulley coincides with the central axis of the traction fixing hole arranged on the distance comb fixing module.

9. The device for measuring the response threshold of a photoelectric speed sensor according to claim 5 or 7, characterized in that: The left guide rail, the front guide rail and the right guide rail are respectively arranged at the left, front and right sides of the base, and the distances between the front guide rail and the left guide rail and the right guide rail are equal.

Images