CN105486265B - Brake glide quantity detector of crane and its measuring method - Google Patents

Abstract

The invention relates to equipment for detecting the sliding amount of a crane, in particular to a crane braking sliding amount detector and a measuring method thereof. It includes a magnetic base that can be adsorbed on the protective cover of the crane hook pulley, a connecting mechanism, a measuring standard ball, a camera, a tripod for fixing and supporting the camera, a braking slide analysis system and a braking slide result expression module; The above-mentioned crane brake slippage detector makes the detection of the crane brake slippage more convenient, accurate and efficient. At the same time, the machine vision technology is used for analysis to ensure that the measurement results are true and effective, and to avoid measurement falsification.

Description

Crane brake sliding amount detector and its measuring method

technical field

The invention relates to equipment for detecting the sliding amount of a crane, in particular to a crane braking sliding amount detector and a measuring method thereof.

Background technique

Crane braking slide is an important index to measure the safety performance of the crane. During the installation, acceptance and use of the crane, it is necessary to detect the braking slide of the crane to ensure production safety. According to the relevant national inspection standards for cranes, if the brake slip exceeds the allowable range, the crane needs to be shut down for maintenance until it meets the relevant standards. Rapid and accurate detection of brake slippage is an important means to improve inspection efficiency and ensure safe operation of cranes.

Contents of the invention

The object of the present invention is to provide a crane brake sliding amount detector and its measuring method, so as to solve the above-mentioned technical problems.

In order to solve the above problems, the technical solution adopted in the present invention is:

A crane braking slippage detector, characterized in that it includes a magnetic base that can be adsorbed on the crane hook pulley protective cover, a connecting mechanism, a measuring standard ball, a camera, a tripod for fixing and supporting the camera, and a braking slippage The analysis system and the brake slippage result expression module; the measurement standard ball is fixed on the magnetic base through the connection mechanism, and is within the field of view of the camera; the camera is connected with the brake slippage analysis system and collects The video signal is transmitted to the brake slip analysis system; the brake slip analysis system is connected with the brake slip result expression module, and the crane brake slip result is obtained by analyzing and calculating the collected video signal. It is transmitted to the brake slip amount result expression module.

Further, the measuring standard ball is a white translucent spherical body, and a light source that can emit light of various colors through wireless control is installed inside it.

The measuring method of the above-mentioned crane brake sliding amount detector is characterized in that: comprising the following steps:

1. Preparatory work: Adsorb the magnetic base on the protective cover of the crane hook pulley, and hang the rated load on the crane hook; by adjusting the tripod, keep the camera at a horizontal position; The location of the shooting, and by adjusting the position of the crane hook, ensure that the measuring standard ball is within the field of view of the camera, and at the same time, ensure that the measuring standard ball is within the field of view of the camera during the entire measurement process;

2. Measurement: Operate the crane so that under the action of the rated load, it will drop at a constant speed from stillness until the brake stops; the camera will record the entire movement process of the measuring standard ball in video form, and transmit the video signal to the brake. Slippage analysis system;

3. Calculation:

Ⅰ. The braking slide analysis system extracts the image information of the measuring standard ball from the received video signal, and calculates the center pixel coordinate change function P(t) of the measuring standard ball in the field of view; then, the obtained Center of sphere pixel coordinate change function P (t) is converted into actual displacement motion function H (t)=T*P (t) by pixel distance and true distance conversion coefficient T, draws the displacement curve figure of measuring standard ball;

The calculation method of the conversion coefficient T between the pixel distance and the real distance: process the image of the measuring standard sphere in the collected video to obtain the pixel diameter D _P of the measuring standard sphere, and the actual diameter of the measuring standard sphere is a known quantity D, then the pixel distance and The true distance conversion coefficient T is expressed as:

Ⅱ. The analysis system of braking slippage will obtain the H(t) function to obtain the derivation, and obtain the running speed function of the crane as: V(t)=∫A(t)dt

Thus, the brake slip analysis system can obtain the running speed curve of the crane;

Ⅲ. The analysis system of braking slide amount analyzes the static speed area AB before the crane descends, the uniform acceleration descending speed area BC of the crane, the uniform descending speed area CD of the crane, and the braking speed area DE of the crane descending according to the crane running speed function V(t). Crane braking stop speed area EF;

Ⅳ. Use the least squares method to carry out segmental fitting on the obtained actual speed curve, and obtain the speed function of each speed area, where:

① The speed fitting curve of the static speed area AB before the crane descends is expressed as:

V(t) _AB ＝K ₁ , K ₁ is the load speed before static and the value after fitting is zero

② The speed fitting curve of the uniform acceleration and descent speed area BC of the crane is expressed as:

V(t) _BC ＝K ₂ *t+K ₃

③ The speed fitting curve of the crane’s uniform descending speed area CD is expressed as:

V(t) _CD ＝K ₄ , K ₄ is the uniform descending speed

④The speed fitting curve of crane descending braking speed area DE is expressed as:

V(t) _DE ＝K ₅ *t+K ₆

⑤ The speed fitting curve of the crane braking stop speed area EF is expressed as:

V _EF (t)＝K ₇ , K ₇ is the load speed after braking, and the value after fitting is zero

After fitting according to the measured speed curve data, the numerical values of K ₁ , K ₂ , K ₃ , K ₄ , K ₅ , K ₆ and K ₇ can be calculated respectively;

Ⅴ. Crane braking slide amount is the moving distance of the crane during the uniform deceleration and descending process in the descending braking speed zone DE. According to the above-mentioned CD, DE, and EF stage fitting equations, the braking slide amount H can be expressed as:

According to the experimental data obtained from the on-site inspection, K7 is the running speed of the crane after braking, and its value is 0. Therefore, the result of the brake sliding amount H is expressed as:

Beneficial effects: compared with the prior art, the crane braking slippage detector of the present invention makes the detection of the crane braking slippage more convenient, accurate and efficient, and at the same time, the machine vision technology is used for analysis to ensure the measurement results Authentic and effective, to avoid measurement falsification.

Description of drawings

Fig. 1 is a schematic diagram of the principle of the present invention;

Fig. 2 is the displacement curve figure of measuring standard sphere described in the present invention;

Fig. 3 is the crane operating speed graph obtained by the brake sliding amount analysis system described in the present invention;

Fig. 4 is the ideal speed graph of crane operation described in the present invention;

Fig. 5 is a fitting curve diagram of the running speed of the crane described in the present invention.

Detailed ways

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

With reference to Fig. 1, the crane brake sliding amount detector of the present invention comprises the magnetic base 1 that can be adsorbed on the crane hook pulley protective cover 9, the connecting mechanism 2, the measuring standard ball 3, the video camera 5, and is used for fixing support The tripod 6 of the camera 5 , the brake slide amount analysis system 7 and the brake slide amount result expression module 8 .

The measurement standard ball 3 is a white translucent spherical body, and a light source 4 that can emit light of various colors through wireless control is housed inside it. According to the different measurement environments, adjust the appropriate luminous color to facilitate the extraction of standard ball image information from the video. The lighting control circuit of the light source 4 can be controlled by software for measuring the amount of brake slip, and can also be controlled by an independent wireless controller.

The measuring standard ball 3 is fixed on the magnetic base 1 through the connection mechanism 2 and is within the field of view of the camera 5 . The camera 5 is connected with the braking slip analysis system 7 , and the video signal collected by it is transmitted to the braking slip analysis system 7 . The braking slippage analysis system 7 is connected with the braking slippage result expression module 8, and the crane braking slippage result obtained by analyzing and calculating the collected video signal is transmitted to the braking slippage result expression module 8.

The measuring method of the crane brake sliding amount detector of the present invention comprises the following steps:

1. Preparatory work: Adsorb the magnetic base 1 on the crane hook pulley protective cover 9, hang the rated load 10 on the crane hook; adjust the tripod 6 to keep the camera 5 in a horizontal position; adjust the connection mechanism 2 to make the measurement The standard ball 3 is in a position that is easy to be photographed by the camera 5, and by adjusting the position of the crane hook, it is ensured that the measurement standard ball 3 is within the field of view of the camera 5. To the motion process of descending and stopping), the measuring standard ball 3 is all in the field of view of the camera 5;

2. Measurement: Operate the crane so that under the action of the rated load 10, it starts to drop at a constant speed from a standstill until the brake stops; the camera 5 records the entire movement process of the measuring standard ball 3 in video form, and transmits the video signal To the braking slip analysis system 7;

3. Calculate:

(1) Brake slip analysis system 7 extracts the image information of measurement standard ball 3 from receiving video signal, and calculates the ball center pixel coordinate change function P (t) of measurement standard ball 3 in the field of vision; Then, The obtained ball center pixel coordinate change function P(t) is converted into the actual displacement motion function H(t)=T*P(t) through the pixel distance and the real distance conversion coefficient T, and the displacement curve of the measurement standard ball 3 is obtained Figure, as shown in Figure 2;

The calculation method of the conversion coefficient T between the pixel distance and the real distance: process the image of the measurement standard sphere 3 in the collected video to obtain the pixel diameter D _P of the measurement standard sphere 3 , and the actual diameter of the measurement standard sphere 3 is a known quantity D, then the pixel distance The conversion factor T with the real distance is expressed as:

(2) The braking slippage analysis system 7 derives the obtained H(t) function to obtain the crane running speed function as: V(t)=∫A(t)dt

Thus, the brake slip analysis system 7 draws the crane running speed curve, as shown in Figure 3;

It can be seen from Figure 3 that the AB stage is the static stage before the rated load 10 moves, the BC stage is the acceleration stage of the rated load 10 from static to uniform speed drop, the CD stage is the rated load 10 constant speed drop stage, and the DE stage is the rated load 10 Deceleration stage from uniform speed down to brake stop, EF stage is rated load 10 static stage after brake stop.

The ideal process of the crane movement is: static—uniformly accelerated descent—uniformly accelerated descent—uniformly decelerated descent—stop, and its ideal speed curve is shown in Figure 4.

By comparing Figure 3 and Figure 4, there is a certain difference between the actual measured speed curve and the ideal speed curve, which is mainly due to the influence of the wire rope vibration and the measurement accuracy error during the crane's descent.

(3) The analysis system 7 for the amount of braking slide can analyze according to the function V(t) of the operating speed of the crane: the static speed area AB before the crane descends, the uniform acceleration descending speed area BC of the crane, the uniform descending speed area CD of the crane, and the braking speed of the crane descending Area DE, crane braking stop speed area EF.

(4) The least square method is used to carry out segmental fitting on the obtained actual velocity curve to obtain the velocity function of each velocity region, wherein:

① The speed fitting curve of the static speed area AB before the crane descends is expressed as:

V(t) _AB ＝K ₁ , K ₁ is the load speed before static and the value after fitting is zero

② The speed fitting curve of the uniform acceleration and descent speed area BC of the crane is expressed as:

V(t) _BC ＝K ₂ *t+K ₃

③ The speed fitting curve of the crane’s uniform descending speed area CD is expressed as:

V(t) _CD ＝K ₄ , K ₄ is the uniform descending speed

④The speed fitting curve of crane descending braking speed area DE is expressed as:

V(t) _DE ＝K ₅ *t+K ₆

⑤ The speed fitting curve of the crane braking stop speed area EF is expressed as:

V _EF (t)＝K ₇ , K ₇ is the load speed after braking, and the value after fitting is zero

After fitting according to the measured velocity curve data, the numerical values of K ₁ , K ₂ , K ₃ , K ₄ , K ₅ , K ₆ and K ₇ can be calculated respectively, and the fitted velocity curve is shown in Figure 5;

(5) Crane brake slippage is the moving distance of the crane during the uniform deceleration and descent in the descending braking speed zone DE. According to the above CD, DE, and EF stage fitting equations, the brake slide amount H can be expressed as:

According to the experimental data obtained from the on-site inspection, K7 is the running speed of the crane after braking, and its value is 0. Therefore, the result of the brake sliding amount H is expressed as:

Claims (1)

1. A measuring method of a crane braking slippage detector, said crane brake slippage detector comprising a magnetic base (1) and a connecting mechanism (2) that can be adsorbed on the crane hook pulley protective cover (9) , a measuring standard ball (3), a video camera (5), a tripod (6) for fixedly supporting the video camera (5), a braking glide analysis system (7) and a braking glide result expression module (8); The measurement standard ball (3) is a white translucent spherical body, and a light source (4) that can emit light of various colors through wireless control is housed inside it; seat (1), and within the field of view of the camera (5); the camera (5) is connected to the brake slip analysis system (7), and the video signal collected by it is transmitted to the brake slip analysis system System (7); the braking sliding amount analysis system (7) is connected with the braking sliding amount result expression module (8), and the crane braking sliding amount result obtained by analyzing and calculating the collected video signal Transmitted to the brake sliding amount result expression module (8); it is characterized in that: the measuring method comprises the following steps: (1) Preparatory work: Adsorb the magnetic base (1) on the crane hook pulley protective cover (9), and hang the rated load (10) on the crane hook; by adjusting the tripod (6), the camera (5) is kept at Horizontal position; by adjusting the connection mechanism (2), make the measuring standard ball (3) be in a position that is easy for the camera (5) to shoot, and by adjusting the position of the crane hook, ensure that the measuring standard ball (3) is in the position of the camera (5) At the same time, it is necessary to ensure that the measurement standard ball (3) is within the field of view of the camera (5) during the entire measurement process; (2) Measurement: Operate the crane so that under the action of the rated load (10), it starts to drop at a constant speed from rest until it is stopped by braking; the camera (5) records the entire movement process of the measuring standard ball (3) in video form , and transmit the video signal to the brake slip analysis system (7); (3) Calculation: (I) Brake sliding amount analysis system (7) extracts the image information of the measurement standard ball (3) from the received video signal, and calculates the center pixel coordinate change function P of the measurement standard ball (3) in the field of view (t); then, the obtained sphere center pixel coordinate change function P(t) is converted into the actual displacement motion function H(t)=T*P(t) through the pixel distance and the real distance conversion coefficient T, and the measured The displacement curve figure of standard ball (3); The calculation method of the pixel distance and the real distance conversion coefficient T: process the image of the measuring standard sphere 3 in the collected video to obtain the pixel diameter D _P of the measuring standard sphere (3), and the actual diameter of the measuring standard sphere (3) is known The amount D, then the conversion coefficient T between the pixel distance and the real distance is expressed as: (II) The analysis system for braking slippage (7) derives the obtained H(t) function, and obtains the operating speed function of the crane as: V(t)=∫A(t)dt Thus, the brake slip analysis system (7) draws the running speed curve of the crane; (Ⅲ) Analysis system of brake sliding amount (7) According to the crane running speed function V(t), the static speed area AB before the crane descending, the crane uniform acceleration descending speed area BC, the crane uniform descending speed area CD, the crane descending brake Speed area DE, crane braking stop speed area EF; (Ⅳ) Using the least squares method to fit the obtained actual velocity curve in sections to obtain the velocity functions of each velocity region, where: ① The speed fitting curve of the static speed area AB before the crane descends is expressed as: V(t) _AB ＝K ₁ , K ₁ is the load speed before static and the value after fitting is zero ② The speed fitting curve of the uniform acceleration and descent speed area BC of the crane is expressed as: V(t) _BC ＝K ₂ *t+K ₃ ③ The speed fitting curve of the crane’s uniform descending speed area CD is expressed as: V(t) _CD ＝K ₄ , K ₄ is the uniform descending speed ④The speed fitting curve of crane descending braking speed area DE is expressed as: V(t) _DE ＝K ₅ *t+K ₆ ⑤ The speed fitting curve of the crane braking stop speed area EF is expressed as: V _EF (t)＝K ₇ , K ₇ is the load speed after braking, and the value after fitting is zero After fitting according to the measured speed curve data, the numerical values of K ₁ , K ₂ , K ₃ , K ₄ , K ₅ , K ₆ and K ₇ can be calculated respectively; (Ⅴ) Crane braking slippage is the moving distance of the crane in the process of uniform deceleration and descent in the descending braking speed region DE. According to the above CD, DE, and EF stage fitting equations, the braking slippage H can be expressed as: According to the experimental data obtained from the on-site inspection, K7 is the running speed of the crane after braking, and its value is 0. Therefore, the result of the brake sliding amount H is expressed as: