Method for measuring rotation speed of equidistant stripes

Abstract

The invention provides an equidistant stripe rotating speed measuring method, which solves the strict requirements on the diameter of a large shaft, the perimeter of a wheel shaft, the stripe spacing and the spacing between the large shaft and a receiver in the prior art. The method comprises the following steps: sticking equidistant reflective stripe stickers on the edge of a detected large-shaft turntable; the laser transmitters and the laser receivers are installed on a measuring support of the mechanical measuring instrument in pairs; due to the design of the equidistant reflective stripe stickers, when the large shaft rotates by a certain distance, the laser receiver receives a fixed number of pulses; and calculating the number of pulses received per unit time so as to determine the rotating speed of the large shaft. The method adopts the infrared laser, is not interfered by water vapor, is high in measurement precision, does not need to accurately measure and adjust the wheel diameter, the perimeter, the stripe interval and the distance between the large shaft and the receiver, and simplifies the field operation. The sticker pasting method is simple and easy to implement, is suitable for large shafts with different diameters and perimeters, and has wide applicability and high resolution.

Description

Technical Field

[0001] The invention relates to the field of rotation speed measurement of industrial automation, and in particular to a rotation speed measurement method of equidistant stripes. Background Art

[0002] In industrial automation, it is crucial to accurately measure the rotational speed of large shafts of equipment such as turbines. Currently, photoelectric encoders are the most commonly used measurement tools, which can convert rotational motion into electrical signals for monitoring rotation angle, speed and acceleration. Photoelectric encoders are divided into two types: incremental and absolute. The former measures relative position changes by detecting pulses generated by the grating, while the latter provides a unique encoding value for each position, and the current position can be read immediately even if the power is off.

[0003] However, when the resolution of the photoelectric encoder is improved, the output pulse frequency will increase, affecting the reliability at high speed. In addition, the encoder has a complex structure, is difficult to install and debug, has high installation accuracy requirements, and is not easy to move after installation, which may affect the running accuracy of the object being measured. Especially when using an absolute encoder, the duration of each pulse cycle is uncertain, which increases the measurement error. These problems limit the application of photoelectric encoders in high-precision measurement. Summary of the invention

[0004] In view of the technical problems existing in the background technology, the present invention provides a method for measuring the rotation speed of equidistant stripes; the method has no requirements on the diameter of the main shaft, the circumference of the wheel shaft, the spacing of the stripes, the spacing between the main shaft and the receiver, and has high measurement accuracy. The method can be realized with only one equidistant reflective stripe sticker and one main shaft.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve: A method for measuring the rotation speed of equidistant stripes, the method comprising the following steps: S1. Paste equidistant reflective stripe stickers on the edge of the turntable of the large shaft to be tested; S2. Install the laser transmitter and the laser receiver in pairs on the measuring bracket of the mechanical measuring instrument so that the laser beam emitted by the laser transmitter is irradiated onto the equidistant reflective stripe sticker; S3. The equidistant reflective stripes of the sticker are designed so that the laser receiver receives a fixed number of pulses every time the main shaft rotates a certain distance; S4. Calculate the number of pulses received per unit time to determine the rotation speed of the main shaft. In the preferred solution, in S1, the length of the equally spaced reflective stripes on the equally spaced reflective stripe sticker is an equal division of the perimeter of the equally spaced reflective stripe sticker, and the length is 0.5C / n cm; Where: C is the circumference of the measured major axis, and n is the number of stripes.

[0006] In the preferred solution, in S1, each centimeter of the equidistant reflective stripe sticker adhesive surface is divided into m equidistant reflective stripes, and the length of each equidistant reflective stripe is b / m centimeters, where b is the calibrated length of the stripe.

[0007] In a preferred solution, in S2, the laser emitter emits an infrared parallel laser beam with a laser wavelength range of 850nm-940nm, a laser divergence angle of 5-10 degrees, a circular light-emitting area, and a diameter range of 3-9cm.

[0008] In a preferred embodiment, in S3, the spacing distance L between the laser emitter and the laser receiver satisfies the following conditions: when one equidistant reflective stripe is provided in the equidistant segment, L ≤ 0.5C / n; when two equidistant reflective stripes are provided in the equidistant segment, 2L ≤ 0.5C / n; when three equidistant reflective stripes are provided in the equidistant segment, 3L ≤ 0.5C / n; when n equidistant reflective stripes are provided in the equidistant segment, (n-1)L ≤ 0.5C / n.

[0009] In a preferred embodiment, in S3, the angle θ between the laser emitter and the laser receiver satisfies the following conditions: when two equidistant reflective stripes (201) are provided in the equidistant segment, θ ≤ 180° / cos(0.5L / 0.5C / n); when three equidistant reflective stripes (201) are provided in the equidistant segment, θ ≤ 180° / cos(L / 0.5C / n); when n equidistant reflective stripes (201) are provided in the equidistant segment, θ ≤ 180° / cos((n-1)L / 0.5C / n).

[0010] In a preferred embodiment, in S1, the equidistant reflective stripe sticker can be pasted on the large shaft to be measured, or on the drive belt shaft of the shaft to be measured, or on the gear shaft to be measured, or on the sleeve of the shaft to be measured, or on the chuck with the measuring shaft, or on the coupling with the measuring shaft.

[0011] In a preferred solution, in S4, the laser receiver pulse calculation method is: 1. When the main axis rotates 0.5C / n, the laser receiver receives m pulses; 2. Therefore, when the main axis rotates 1 cm, the number of pulses received by the laser receiver is: (indivual); 3. When the main shaft rotates one circle (i.e. C cm), the number of pulses received by the laser receiver is 2mn (pieces); In the preferred solution, in S4, the calculation method of the main shaft speed is: 1. Assume that the total number of pulses received by the laser receiver within t seconds is P (pieces); 2. The speed N (revolutions per minute, rpm) of the main shaft in t seconds can be calculated by the following formula: (rpm).

[0012] A method for measuring rotation speed of equidistant stripes, the beneficial effects of the method include but are not limited to the following points: 1. Through the design of equidistant reflective stripe stickers, the laser receiver can receive a fixed number of pulses every time the main shaft rotates a certain distance, thereby accurately calculating the rotation speed; using infrared laser, it is not affected by water vapor, ensuring high accuracy and reliability of measurement; 2. It only needs to measure the wheel diameter accurately on site, but not the circumference or the stripe spacing accurately. It only needs to adjust the distance between the main shaft and the receiver accurately, which greatly simplifies the on-site installation and debugging process. 3. The measurement method has nothing to do with the diameter of the large shaft and is applicable to large shafts of different diameters. The measurement method has nothing to do with the circumference of the large shaft axle and is applicable to large shafts of different circumferences. The measurement method has nothing to do with the stripe spacing. The smaller the stripe spacing, the more stripes there are in the same circumference, which improves the measurement resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structural principle of the present invention; Figure 2 The figure is a schematic diagram of the positions of the reflective stripes on the reflective stripe sticker of the present invention.

[0014] In the figure: a main shaft 1, a reflective stripe sticker 2, a reflective stripe 201, a laser transmitter 3, and a laser receiver 4. DETAILED DESCRIPTION

[0015] The present invention provides a method for measuring the rotation speed of an equidistant stripe, which realizes high-precision measurement of the rotation speed of a large shaft of a water turbine by using an equidistant reflective stripe sticker, a laser transmitter and a laser receiver. The following are three specific embodiments, which show the application and effect of the method under different conditions.

[0016] Example 1: Measuring the main shaft speed under standard conditions; 1. Equipment configuration: 1.1. The equidistant reflective stripe sticker is pasted on the edge of the wheel disc of the main shaft. Each centimeter of the equidistant reflective stripe sticker pasting surface is divided into 100 equidistant reflective stripes; 1.2. Emitting an infrared parallel laser beam with a wavelength of 900nm, a laser divergence angle of 5 degrees, a circular luminous area with a diameter of 5cm; 1.3. The sensing surface is semicircular with a diameter of 3cm and is installed at a 90° angle to the laser emitter; 2. Parameter settings: 2.1. The circumference of the main axis is C = 1000 cm; 2.2, the number of equally spaced reflective stripes is n=100; 2.3. The number of equally spaced reflective stripes on the adhesive surface of the equally spaced reflective stripe sticker per centimeter is m=100; Measuring time t=1 second; Measuring process: 3.1. Paste the equidistant reflective stripe stickers on the edge of the wheel disc of the large shaft; 3.2. Install the laser transmitter and laser receiver so that they form a 90° angle; 3.3. Turn on the laser transmitter, the laser beam will be irradiated onto the equidistant reflective stripe sticker, and the laser receiver will receive the reflected laser beam; 3.4. Record the total number of pulses received by the laser receiver within 1 second, P = 5000; 4. Calculation results: = = =15rpm.

[0017] Example 2: Measuring the rotation speed of the main shaft under different stripe equal fraction conditions; 1. Equipment configuration: 1.1. The equidistant reflective stripe sticker is pasted on the edge of the wheel disc of the main shaft. Each centimeter of the equidistant reflective stripe sticker pasting surface is divided into 50 equidistant reflective stripes; 1.2. The emission wavelength is 850nm, the laser divergence angle is 7 degrees, the luminous area is circular, and the diameter is 6cm; 1.3. The sensing surface is semicircular with a diameter of 4cm and is installed at a 90° angle to the laser transmitter; 2. Parameter settings: 2.1. The circumference of the main axis is C = 1200 cm; 2.2, the number of equally spaced reflective stripes is n=120; 2.3. The number of equally spaced reflective stripes on the adhesive surface of the equally spaced reflective stripe sticker per centimeter is m=50; Measuring time t=2 seconds; Measuring process: 3.1. Paste the equidistant reflective stripe stickers on the edge of the wheel disc of the large shaft; 3.2. Install the laser transmitter and laser receiver so that they form a 90° angle; 3.3. Turn on the laser transmitter, the laser beam will be irradiated onto the equidistant reflective stripe sticker, and the laser receiver will receive the reflected laser beam; 3.4. Record the total number of pulses received by the laser receiver within 1 second, P = 12000; 4. Calculation results: = = =30rpm.

[0018] Example 3: Measuring the rotation speed of the main shaft under different main shaft diameter conditions; 1. Equipment configuration: 1.1. The equidistant reflective stripe sticker is pasted on the edge of the wheel disc of the main shaft. Each centimeter of the equidistant reflective stripe sticker pasting surface is divided into 80 equidistant reflective stripes; 1.2. The emission wavelength is 940nm, the laser divergence angle is 10 degrees, the luminous area is circular, and the diameter is 7cm; 1.3. The sensing surface is semicircular with a diameter of 5cm and is installed at a 90° angle to the laser emitter; 2. Parameter settings: 2.1. The circumference of the main axis is C = 800 cm; 2.2, the number of equally spaced reflective stripes is n=80; 2.3. The number of equally spaced reflective stripes on the adhesive surface of the equally spaced reflective stripe sticker per centimeter is m=80; Measuring time t=1 second; Measuring process: 3.1. Paste the equidistant reflective stripe stickers on the edge of the wheel disc of the large shaft; 3.2. Install the laser transmitter and laser receiver so that they form a 90° angle; 3.3. Turn on the laser transmitter, the laser beam will be irradiated onto the equidistant reflective stripe sticker, and the laser receiver will receive the reflected laser beam; 3.4. Record the total number of pulses received by the laser receiver within 1 second, P = 6400; 4. Calculation results: = = =30rpm.

[0019] Through the above three embodiments, it can be seen that the equidistant stripe rotation speed measurement method of the present invention has the following advantages: 1. Through the cooperation of equidistant reflective stripe stickers and laser receivers, the rotation speed of the large shaft can be accurately calculated; 2. There is no need to accurately measure and adjust the wheel diameter, circumference, stripe spacing and the distance between the large shaft and the receiver, which simplifies the on-site operation; 3. It is suitable for large shafts of different diameters and circumferences, is not affected by the stripe spacing, and has broad application prospects.

[0020] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from all points of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention; any reference numerals in the claims should not be regarded as limiting the claims involved.

Claims

1. A method for measuring the rotation speed of equidistant fringes, characterized in that: The measurement method includes the following steps: S1. Paste equidistant reflective stripe stickers (2) on the edge of the turntable of the large shaft (1) to be tested; S2, mounting a laser transmitter (3) and a laser receiver (4) in pairs on a measuring bracket of a mechanical measuring instrument, so that the laser beam emitted by the laser transmitter (3) is irradiated onto the equidistant reflective stripe sticker (2); S3, the equidistant reflective stripes (201) of the equidistant reflective stripe sticker (2) are designed so that when the large shaft (1) rotates a certain distance, the laser receiver (4) receives a fixed number of pulses; S4. Calculate the number of pulses received per unit time to determine the rotation speed of the main shaft (1).

2. The equidistant fringe speed measurement method according to claim 1, characterized in that: In S1, the length of the equally-spaced reflective stripes (201) on the equally-spaced reflective stripe sticker (2) is an equal division of the circumference of the equally-spaced reflective stripe sticker (2), and the length is 0.5C / n cm; Where: C is the circumference of the measured major axis (1), and n is the number of stripes.

3. The equidistant fringe rotation speed measurement method according to claim 1, characterized in that: In S1, the adhesive surface of the sticker (2) with equally spaced reflective stripes per centimeter is divided into m equally spaced reflective stripes (201), and the length of each equally spaced reflective stripe (201) is b / m centimeters, where b is the calibrated length of the stripe.

4. The equidistant fringe rotation speed measurement method according to claim 1, characterized in that: In S2, the laser emitter (3) emits an infrared parallel laser beam with a wavelength range of 850nm-940nm, a laser divergence angle of 5-10 degrees, and a circular light-emitting area with a diameter range of 3-9cm.

5. The equidistant fringe rotation speed measurement method according to claim 1, characterized in that: In S3, the distance L between the laser transmitter (3) and the laser receiver (4) satisfies the following conditions: 5.

1. When there is one equidistant reflective stripe (201) in the equidistant segment, L ≤ 0.5C / n; 5.

2. When two equidistant reflective stripes (201) are provided in an equidistant segment, 2L ≤ 0.5C / n; 5.

3. When there are three equidistant reflective stripes (201) in the equidistant segment, 3L ≤ 0.5C / n; 5.

4. When there are n equidistant reflective stripes (201) in an equidistant segment, (n-1)L ≤ 0.5C / n.

6. The equidistant fringe rotation speed measurement method according to claim 1, characterized in that: In S3, the angle θ between the laser transmitter (3) and the laser receiver (4) satisfies the following condition: 6.

1. When two equidistant reflective stripes (201) are provided in an equidistant segment, θ ≤ 180° / cos(0.5L / 0.5C / n); 6.

2. When three equidistant reflective stripes (201) are provided in the equidistant segment, θ ≤ 180° / cos(L / 0.5C / n); 6.

3. When n equidistant reflective stripes (201) are provided in an equidistant segment, θ ≤ 180° / cos((n-1)L / 0.5C / n).

7. The equidistant fringe rotation speed measurement method according to claim 1, characterized in that: In S1, the equidistant reflective stripe sticker (2) can be pasted on the measured large shaft (1), or on the measured shaft transmission belt shaft, or on the measured gear shaft, or on the measured shaft sleeve, or on the measured shaft chuck, or on the measured shaft coupling.

8. The method for measuring rotation speed of equidistant fringes according to any one of claims 1 to 6, characterized in that: In S4, the laser receiver (4) pulse calculation method is: 8.

1. When the main shaft (1) rotates 0.5C / n, the laser receiver (4) receives m pulses; 8.

2. Therefore, when the large shaft (1) rotates 1 cm, the number of pulses received by the laser receiver (4) is: (indivual); 8.

3. When the large shaft (1) rotates one revolution (i.e. C cm), the number of pulses received by the laser receiver (4) is 2 mn.

9. The method for measuring rotation speed of equidistant stripes according to any one of claims 1 to 6, characterized in that: in S4, The speed of the main shaft (1) is calculated as follows: 9.

1. Assume that the total number of pulses received by the laser receiver (4) within t seconds is P (pieces); 9.2, then the speed N (revolutions per minute, rpm) of the main shaft (1) in t seconds can be calculated by the following formula: (rpm).

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