Unmanned aerial vehicle application type pipeline flow velocity detection system and method

Abstract

The invention discloses an unmanned aerial vehicle application type pipeline flow velocity detection system and method, and belongs to the technical field of unmanned aerial vehicle intelligent detection, and the system comprises a detection device which is provided with a horizontally arranged straight rod part, and one end of the straight rod part is provided with a first flow meter unit and a pipeline wall thickness detector; a first flowmeter unit is arranged at one end of the straight rod component, a second flowmeter unit is arranged at the other end of the straight rod component, a first alignment mark and a second alignment mark are arranged on the upper surface of the straight rod component, and the connecting line of the center points of the first alignment mark and the second alignment mark and the center line of the straight rod component are arranged in parallel on the vertical plane. An unmanned aerial vehicle and a control host; the invention further comprises a method for accurately arranging the detection device, and convenience and accuracy of pipeline flow velocity detection operation can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned aerial vehicle intelligent detection, and particularly relates to a kind of unmanned aerial vehicle application formula pipe flow velocity detection system and method. BACKGROUND

[0002] In industrial production, the flow velocity of liquid in the pipeline needs to be accurately measured and controlled. Some large-diameter pipelines need to be equipped with electromagnetic flow meters. For outdoor conveying pipelines, some pipelines may be arranged underground, and some pipelines may be arranged on the ground, road or river in a cross-beam or suspended beam structure. At the same time, outdoor pipelines usually have harsh environments, such as extreme temperature changes and climate changes. Therefore, these flow meters must be regularly detected and calibrated to ensure accurate and reliable feedback of flow rate values.

[0003] Flow meters are industrial instruments for measuring liquid flow and are suitable for pipeline fluid monitoring in fields such as petroleum, chemical industry, environmental protection, and nuclear power. They are based on time difference method or Doppler effect principle. The time difference method is suitable for pure liquids, and the Doppler method requires the fluid to contain particles or bubbles. These two principles can cover various media such as water, crude oil, and acid-base liquid. The flow rate of liquid in metal, plastic, and other material pipelines can be measured by non-contact method.

[0004] China has vast territory and numerous pipelines, such as long-distance energy conveying pipelines, civil or industrial water conveying pipelines, and pipelines used in ports and factories. These pipelines need to be regularly detected, and flow rate detection and calibration are important parts of the detection. Traditional operations are usually carried out manually, which has high operation risk, low detection accuracy, and difficulty in reaching complex environments. Generally, ultrasonic flow meters used for detection need to be arranged at the straight section of the pipeline, which requires more than 10 times the pipe diameter upstream and more than 5 times the pipe diameter downstream. For example, some flow meters are installed underground and do not have a straight pipe section exposed to the ground, so they cannot be measured. The straight pipe section exposed to the ground spans the river or river surface, which poses a certain risk for engineers to operate on the river surface. Some pipelines have intrusion prevention devices to prevent accidents, so it is difficult for humans to reach and arrange detection equipment, which also poses a certain risk. Moreover, it is difficult for humans to accurately align the detection equipment with the center line of the pipeline, which can easily reduce the detection accuracy. SUMMARY

[0005] The present application relates to the technical field of unmanned aerial vehicle intelligent detection, and particularly relates to a kind of unmanned aerial vehicle application formula pipe flow velocity detection system and method.

[0006] To achieve the above purpose, the technical scheme of the present application is as follows: A kind of unmanned aerial vehicle application formula pipe flow velocity detection system, comprising: The detection device has a horizontal arrangement of a straight rod component, one end of which is arranged with a first flow meter unit pipe wall thickness detector, and the other end is arranged with a second flow meter unit, the upper surface of the straight rod component is arranged with a first alignment mark and a second alignment mark, the center line of the straight rod component is parallel to the center line of the straight rod component in the vertical plane. The unmanned aerial vehicle has a flight structure and a flight control system, at least one camera capable of vertical downward imaging, and a hoisting mechanism connected to the detection device. The control host operates the unmanned aerial vehicle and the detection device through wired or wireless means, and obtains image information fed back by the unmanned aerial vehicle camera. The bottom of the unmanned aerial vehicle hoisting mechanism includes a clamping component that can limit the operation of the straight rod component and make the center line of the straight rod component parallel to the center line of the unmanned aerial vehicle.

[0007] Further, the straight rod component includes a front rod and a rear rod, which can be adjusted in length in a central alignment manner, the first flow meter unit is arranged at the front end of the front rod, and the second flow meter unit is arranged at the rear end of the rear rod, and the bottom of the first flow meter and the second flow meter is horizontally aligned.

[0008] Further, a pipe wall cleaning unit is arranged at the front end of the front rod and the rear end of the rear rod, which is configured to clean the outer wall of the pipe to be detected, and the first flow meter unit and the second flow meter unit are arranged above the corresponding pipe wall cleaning unit.

[0009] Further, the pipe wall cleaning unit includes a cleaning motor, which is arranged vertically, and is fixedly installed at the bottom of the outer end of the front rod or the rear rod, and the front end of the cleaning motor is arranged with a turntable, three shafts are arranged in a central array on the outer edge of the turntable, the shafts are rotatably connected to the turntable through bearings, brush hairs are installed on the shafts, and gears are arranged on the outer side of the shafts connected to the turntable, and a tooth ring is fixedly arranged at the bottom of the front rod or the rear rod, the tooth ring is arranged in a central alignment manner with the turntable, and the top of all gears is in meshing state with the tooth ring.

[0010] Further, the shafts are arranged with metal wire brush hairs, plastic wire brush hairs and flexible spiral pieces in a spiral structure, and the plastic wire brush hairs, metal wire brush hairs and flexible spiral pieces are arranged in a structure with the outer diameter gradually decreasing.

[0011] Further, the bottom of the front rod is arranged with an alignment adjustment mechanism for adjusting the position and angle of the straight rod component in the pipe.

[0012] Further, the alignment adjusting mechanism comprises a first rotating part arranged at the rear end of the front rod and a second rotating part arranged at the front end of the front rod, the first rotating part and the second rotating part each comprise an alignment motor, the alignment motor is connected with a reducer in a matched mode, an adjusting disc is arranged at the rear end of the reducer, the alignment motor can drive the adjusting disc to rotate, an adjusting rod is arranged vertically at the eccentric position of the adjusting disc, a first mounting plate is arranged at the top of the first rotating part, the first mounting plate is fixedly installed at the bottom of the front rod, a circular through hole is arranged on the first mounting plate, the adjusting rod passes through the circular through hole, an end plate is arranged at the top of the adjusting rod, and the circular through hole is in close contact with the adjusting rod; the second rotating part is similar in structure to the first rotating part, a second mounting plate is arranged at the top of the second rotating part, the second mounting plate is fixedly installed at the bottom of the front rod, an oblong hole is arranged on the second mounting plate, the adjusting rod passes through the oblong hole, an end plate is arranged at the top of the adjusting rod, the oblong hole is in close contact with the adjusting rod, and the adjusting rod of the second rotating part can be horizontally displaced in the oblong hole; the center point of the first alignment mark is vertically arranged in alignment with the center point of the circular through hole; Further, the first flowmeter unit or the second flowmeter unit comprises a straight cylinder, and an ultrasonic detector is arranged in the straight cylinder, wherein a probe of the ultrasonic detector is arranged at a central position in the straight cylinder, the ultrasonic detector is arranged in a sliding mode in the straight cylinder, an elastic cover plate is arranged at the bottom of the straight cylinder, a vertical sliding groove and a sliding block are arranged on the side wall of the straight cylinder, the sliding block is connected with a driving end of a servo cylinder, and a pipe wall thickness detector is arranged at the side of the ultrasonic detector in the straight cylinder of the first flowmeter unit.

[0013] A method for accurately arranging a detection device, applied to the unmanned aerial vehicle application type pipe flow rate detection system, comprises the following steps: S1, setting the length of the straight rod part according to the diameter of the pipe to be detected; S2, under the control of the control host, the unmanned aerial vehicle clamps and conveys the detection device through the hoisting mechanism; S3, the unmanned aerial vehicle conveys the detection device to a predetermined position of the pipe to be detected, and places the detection part as much as possible above the center line of the pipe; S4, the cleaning motor of the pipe wall cleaning unit drives the turntable and the rotating shaft to perform horizontal revolution, the rotating shaft performs revolution around its center line under the action of the gear and the toothed disc, so as to realize the cleaning operation on the pipe to be detected, and when the turntable stops working, the first flowmeter unit or the second flowmeter unit is located between the adjacent rotating shaft and the bristle. S5, the unmanned aerial vehicle hovers above the detection device and the pipe, and obtains an imaging photo including the first alignment mark and the second alignment mark of the detection device and the pipe profile through the camera. S6 in the imaging photo, the pipe profile is edge finding processing, by finding the edge line of the two sides of the pipe, after determining the two side edge lines, the center line L1 of the pipe is obtained, the continuous L2 through the center point A1 of the first alignment mark and the center point A2 of the second alignment mark is obtained, and the distance value L12 between A1 and L1 is calculated;If the value of L12 is greater than or equal to the set threshold value, at the first rotating part, the angle value of moving A1 to L1 is calculated based on the value of L10, and then A1 is arranged on the line L1 by the first rotating part; S7 with A1 point as the vertex, the angle value A11 between L1 and L2 is calculated and obtained, if the value of A11 is greater than or equal to the set threshold value, at the second rotating part, the angle value of moving A2 to L1 is calculated based on the value of L11 and L10, and then A2 is arranged on the line L1 by the second rotating part, and the coincidence state of L2 and L1 is completed; S8 controls the host to control the downlink operation of the first flowmeter unit and the second flowmeter unit, and makes the lower end thereof closely adhere to the outer wall of the pipe according to its own gravity, and then the wall thickness value of the current pipe is obtained by the pipe wall thickness detector, and the first flowmeter unit and the second flowmeter unit detect the flow of the fluid in the pipe according to the time difference method or the principle of Doppler effect to obtain the flow rate value of the current pipe liquid.

[0014] Further, in step S6, if the value of L12 is greater than the radius value of the adjusting rod to the adjusting disc, or in step S7, if the value of A11 is greater than the maximum value of the adjusting rod to the adjusting disc that can be adjusted by the second rotating part, return to step S2.

[0015] Compared with the prior art, the scheme has the following beneficial effects: An unmanned aerial vehicle application type pipe flow rate detection system provides a pipe flow rate detection system combining unmanned aerial vehicles and detection devices. In the scheme, the detection device can be arranged at various unconventional pipes, such as rivers, high buildings or complex fields, by the unmanned aerial vehicle carrying the detection device. The operator can remotely control and continuously work at multiple detection points according to the set cruise route, thereby reducing the operation difficulty and risk and improving the detection efficiency. The scheme is implemented by the unmanned aerial vehicle cooperating with the detection device. In conventional manual detection, the equipment needs to be placed by manual alignment. However, on a narrow and uneven pipe, the placement and alignment may not be accurate enough, which may cause detection errors. In the scheme, the entire arrangement structure is photographed by the imaging mode of the camera of the unmanned aerial vehicle, and the detection component can be accurately arranged above the center line of the pipe by the position adjustment function of the detection device, so that the detection accuracy can be greatly improved. The detection device of the scheme integrates cleaning, positioning adjustment and detection functions, solves the problems of incomplete cleaning and low positioning accuracy in traditional manual operation, and greatly reduces the manual intensity of outdoor detection work. The method for precisely arranging the detection device comprises the following steps: imaging and calculating the distance and angle relationship between the pipeline center line L1 and the detection device center line L2. When the deviation is within a controllable range, the detection device is controlled by the host computer, and under the cooperation of the unmanned aerial vehicle, the first rotating part and the second rotating part can work cooperatively, so that L1 and L2 can be in a precise alignment state, and the arrangement of the arm is more precise and convenient, and the accuracy of the detection operation is realized. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the preferred embodiment.

[0017] Figure 2 It is a schematic diagram of the hoisting structure of the unmanned aerial vehicle to the detection device.

[0018] Figure 3 It is a schematic diagram of the structure of the detection device.

[0019] Figure 4 It is a top view schematic diagram of the detection device.

[0020] Figure 5 It is a schematic diagram of the structure of the hoisting mechanism.

[0021] Figure 6 It is a schematic diagram of the structure of the pipe wall cleaning unit.

[0022] Figure 7 It is a schematic diagram of the component structure of the pipe wall cleaning unit.

[0023] Figure 8 It is a schematic diagram of the storage state structure of the first flow meter unit.

[0024] Figure 9 It is a schematic diagram of the working state structure of the first flow meter unit.

[0025] Figure 10 It is a schematic diagram of the structure of the alignment adjustment mechanism.

[0026] Figure 11 It is a technical description diagram of the time difference of propagation.

[0027] Figure 12 It is a symbol arrangement diagram of the detection device.

[0028] Figure 13 It is a working schematic diagram of step S6.

[0029] Figure 14A schematic diagram of the working of step S7.

[0030] Figure 15 A schematic diagram of the standard working condition of the detection device. DETAILED DESCRIPTION

[0031] The original intention of the present scheme is to provide an outdoor pipeline flow rate detection system combined with a detection device by using a UAV, which is used for flow rate detection and fixed flow rate verification of various outdoor pipelines, so as to reduce the difficulty and danger of manual detection and improve the convenience and accuracy of detection.

[0032] REFERENCE Figures 1 to 10 A UAV application type pipeline flow rate detection system, comprising: The UAV 1 has a flight structure, a flight control system, a remote control and an image transmission function. The gimbal camera 11 is arranged on the UAV 1, the camera 11 can adjust the angle and take pictures vertically downward.

[0033] The control host is the core control component and data processing center, which has the structure of a typical computer and can operate and control the UAV 1 and the detection device 2 through wired or wireless means based on the control and operation of the operator, and obtain image information feedback from the camera 11, process and analyze the image information, and implement autonomous control and operation in appropriate cases.

[0034] The detection device 2 has a horizontal straight rod component, which includes a front rod 21 and a rear rod 22, and the front rod 21 and the rear rod 22 can be arranged in a track structure and can be adjusted in length in a central alignment manner, and part of the structure of the rear rod 22 can be accommodated inside the front rod 21. In some embodiments, in order to better observe the overall length of the straight rod component, a corresponding scale can be arranged on the upper surface of the rear rod 22. In some embodiments, in order to fix the length of the straight rod component after length adjustment, a limiting bolt 23 is arranged on one side of the front rod 21, which limits the rear rod 22 to make the front rod 21 and the rear rod 22 in a position fixed state.

[0035] In fact, the detection device 2 is an independent working unit, which also has a power supply, a control unit, a communication unit and a line connected to the device, so as to realize the independent working and control of the detection device 2, and realize the control and operation of the control host.

[0036] The first flow meter unit 41 is arranged at the front end of the front rod 21, and the second flow meter unit 42 is arranged at the rear end of the rear rod 22, and the bottoms of the first flow meter 41 and the second flow meter 42 are arranged in a horizontal alignment state. The center of the first flow meter unit 42 and the center of the second flow meter unit 42 are arranged with ultrasonic detectors, and the side of the first flow meter unit 41 is arranged with a pipe wall thickness detector 45.

[0037] The upper surface of the front rod 21 is arranged with a first alignment mark 24 and a second alignment mark 25, and the line connecting the center points of the first alignment mark 24 and the second alignment mark 25 is parallel to the center line of the front rod 21 and the rear rod 22 in a vertical plane. The first alignment mark 24 and the second alignment mark 25 can be color or shape marks, reflective marks, or self-luminous marks. Even in a poor lighting environment, the camera 11 can locate and identify the marks through self-luminous or light reflection, and accurately identify the center points.

[0038] The operator can operate the unmanned aerial vehicle or the detection device through a wired or wireless control host, connect and control the operation parts of the unmanned aerial vehicle or the detection device through a wired or wireless manner, obtain the state and feedback data of the unmanned aerial vehicle camera, and obtain image information feedback by the unmanned aerial vehicle camera. In order to realize the hoisting operation of the unmanned aerial vehicle 1 on the detection device 2, the bottom of the unmanned aerial vehicle 1 is arranged with a hoisting mechanism, the hoisting mechanism includes four rocker arm parts 12, the rocker arm parts 12 are connected with rocker arm electric cylinders 13 and connecting rods, four lifting lugs 26 are arranged on the two sides of the front rod 21, and a flexible pad 14 is arranged at the bottom of the unmanned aerial vehicle 1. When the unmanned aerial vehicle 1 is arranged in a straddle manner above the front rod 21, the flexible pad 14 contacts the upper surface of the front rod 21, the four rocker arm parts 12 are operated in a divergent manner under the action of the rocker arm electric cylinders 13 and the connecting rods, and the lower ends of the four rocker arm parts 12 contact the lower surfaces of the lifting lugs 26, thereby realizing the connection between the unmanned aerial vehicle 1 and the detection device 2, and realizing the clamping and transporting functions of the unmanned aerial vehicle 1 on the detection device 2. Conversely, the two can also be separated. When the hoisting mechanism hoists and limits the straight rod part, the center line of the straight rod part 2 is parallel to the center line of the unmanned aerial vehicle 1.

[0039] In order to remove the soil, dust or other debris on the outer surface of the pipe and improve the detection accuracy, a pipe wall cleaning unit 3 is arranged at the front end of the front rod 21 and the rear end of the rear rod 22, and the pipe wall cleaning unit 3 is arranged above the first flow meter unit 41 and the second flow meter unit 42.

[0040] Specifically, the pipe wall cleaning unit 3 comprises a cleaning motor 31, the cleaning motor 31 is arranged vertically, the cleaning motor 31 is fixedly installed at the bottom of the outer end of the front rod 21 or the rear rod 22, the front end of the cleaning motor 31 is arranged with a rotating disc 32, three rotating shafts 33 are horizontally arranged in a central array at the outer edge of the rotating disc 32, the rotating shaft 33 is rotationally connected with the rotating disc 32 through a bearing, the rotating shaft 33 is arranged with a gear 34 at the outer side connected with the rotating disc 32, a tooth ring 35 is arranged at the outer side of the rotating disc 32, the top of the tooth ring 35 is fixedly installed with the bottom of the front rod 21 or the rear rod 22, the tooth ring 35 is arranged in a central alignment manner with the rotating disc 32, and the top of all the gears 34 is in meshing state with the tooth ring 35.

[0041] Therefore, when the pipe cleaning motor 31 drives the rotating disc 32 and the rotating shaft 33 to perform horizontal revolution, the rotating shaft 33 will perform self-rotation operation with the central line thereof under the cooperation of the gear 34 and the tooth ring 35.

[0042] In order to realize better cleaning operation, the rotating shaft 32 is arranged with plastic wire bristles 36, metal wire bristles 37 and flexible spiral blades 38 in a spiral structure at intervals, and the outer diameters of the plastic wire bristles 36, the metal wire bristles 37 and the flexible spiral blades 38 are arranged in a structure of gradually decreasing. Therefore, through the above structure, the plastic wire bristles 36 and the metal wire bristles 37 can be used for cleaning operation to remove deposits such as soil and rust, so that the surface is smoother, and in the process of self-rotation and revolution, the flexible spiral blades 38 are used to realize lateral and forward pushing and removing operation of sundries, so that the working surface is clean and tidy.

[0043] In the structure, the cleaning motor 31 is a servo motor structure, the position control can determine the size of the rotation speed through the frequency of the externally input pulse, and determine the rotation angle through the number of pulses, and realize accurate rotation speed and rotation angle control, so that the accurate control of the stop position of the three rotating shafts 33 can be realized, so that when the rotating shaft 33 stops running, the first flow meter unit 41 or the second flow meter unit 42 is located at the position between the adjacent rotating shafts 33, so that when the first flow meter unit 41 or the second flow meter unit 42 descends to perform detection operation, interference phenomenon with the rotating shaft 32 and the bristles will not occur.

[0044] In order to realize accurate detection, the first flow meter unit 41 or the second flow meter unit 42 comprises a straight cylinder 43, an ultrasonic detector 44 is arranged inside the straight cylinder 43, wherein the probe of the ultrasonic detector 44 is arranged at the central position inside the straight cylinder 43, the ultrasonic detector 44 is arranged in a sliding manner inside the straight cylinder 43, and a typical structure can be a linear bearing structure. The inside of the straight cylinder of the first flow meter unit 41 is arranged with a pipe wall thickness detector 45 at the side of the ultrasonic detector 44.

[0045] In order to reduce the dust generated by the cleaning unit 3 during the cleaning operation, the dust accumulated on the bottom detection surface of the ultrasonic detector 44, an elastic cover plate 47 is arranged at the bottom of the straight cylinder 43, the elastic cover plate 47 is rotatably connected with the outer wall of the straight cylinder 43, and a torsion spring is arranged therebetween for returning the elastic cover plate to a state of closing the bottom of the straight cylinder 43.

[0046] The side wall of the straight cylinder 43 is provided with a sliding block 48 and a servo cylinder 49 connected with the sliding block 48, and the side wall of the sliding block 48 corresponds to a sliding groove 46 for limiting the up-down displacement of the sliding block 48. The sliding block 48 is an integral structure with the ultrasonic detector 44, so that the sliding block 48 and the sliding groove 46 can ensure that the ultrasonic detector 44 does not deflect in angle during up-down displacement, thereby affecting the accuracy of detection. The top of the servo cylinder 49 can be a spherical structure, which will contact the bottom of the sliding block 48 when it goes up, thereby pushing the sliding block 48 and the ultrasonic detector 44 to go up, and when it goes down, the ultrasonic detector 44 will go down under its own gravity until its lower end contacts and fits the pipe wall, thereby realizing accurate detection operation.

[0047] In order to realize the detection operation better than manual arrangement and placement, an alignment adjusting mechanism is arranged at the bottom of the front rod 21, which is used to adjust the position and angle of the straight rod component 2 placed on the pipeline. Specifically, the alignment adjusting mechanism includes a first rotating component 51 arranged at the rear end of the front rod 21 and a second rotating component 52 arranged at the front end of the front rod 21. The first rotating component 51 and the second rotating component 52 both include an alignment motor 53, which is connected with a speed reducer. An adjusting disc 54 is arranged at the rear end of the speed reducer. The alignment motor can drive the adjusting disc 54 to rotate. An adjusting rod 55 is vertically arranged at the eccentric position of the adjusting disc 54. A first mounting plate 56 is arranged at the top of the first rotating component 51 and fixedly mounted on the bottom of the front rod 21. The first mounting plate 56 is provided with a circular through hole 57, and the adjusting rod 55 is arranged through the circular through hole 57 in clearance fit. An end plate is arranged at the top of the adjusting rod 55 to prevent it from sliding out of the circular through hole 57 and to make the circular through hole 57 and the adjusting rod 55 tightly fit. A second mounting plate 58 is arranged at the top of the second rotating component 52 and fixedly mounted on the bottom of the front rod 21. The second mounting plate is provided with an oblong hole 59, and the adjusting rod 55 is arranged through the oblong hole 59. The other structures are the same as those of the first mounting plate, so the adjusting rod 55 of the second rotating component 52 can horizontally displace in the oblong hole 59.

[0048] In order to facilitate the adjustment and control of the center point of the first alignment mark 24 and the center point of the circular through hole 57 in the vertical direction to be in the aligned arrangement state. In the initial state, the first rotating part 51 and the second rotating part 52 are arranged in a straight line alignment manner below the front rod 21. If necessary, a control structure similar to an electromagnet can be used to make it in a stable arrangement state. Flexible washers can be arranged at the bottom of the first rotating part 51 and the second rotating part 52 to improve the friction and fit of the contact pipeline, so that it can be stably placed.

[0049] The scheme also includes a method for accurately arranging a detection device, applied to the unmanned aerial vehicle application type pipeline flow rate detection system, and the following is a detailed explanation: I. Working principle: Reference Figure 11 The ultrasonic time difference method flowmeter is a commonly used non-contact flow measurement instrument, which uses the propagation time difference of ultrasonic waves to measure the flow rate and flow of fluid. Its working principle is based on the Doppler effect and the characteristics of sound speed propagation. According to the principle of signal detection, ultrasonic flowmeters can be divided into propagation speed difference method (direct time difference method, time difference method, phase difference method and frequency difference method), beam deflection method, Doppler method, cross correlation method, spatial filtering method and noise method, etc.

[0050] Phase difference method: measure the phase difference caused by time difference when measuring the propagation time of forward and reverse propagation. The transmitter sends a beam of sound waves along the axis perpendicular to the pipeline. Due to the effect of fluid flow, the sound beam is offset by a distance downstream. The offset distance is proportional to the flow rate.

[0051] Frequency difference method: measure the frequency difference of the sound ring when the propagation time of forward and reverse propagation. When ultrasonic waves are transmitted in a non-uniform fluid, the sound waves will be scattered. When there is relative motion between the fluid and the transmitter, the transmitted sound wave signal and the signal received after being scattered by the fluid will produce a Doppler frequency shift.

[0052] Time difference method: measure the time difference caused by the difference in propagation speed when measuring the propagation time of forward and reverse propagation. Two sound wave transmitters (SA and SB) and two sound wave receivers (RA and RB) are used. Two groups of sound waves from the same sound source are transmitted between SA and RA and between SB and RB.

[0053] An ultrasonic time-of-flight flow meter consists of two ultrasonic transducers, one as a transmitter and the other as a receiver. The distance between the transmitter and receiver is fixed and is usually installed along the axis of the pipe. When fluid passes through the pipe, the transmitter emits ultrasonic pulses into the fluid, which propagate through the fluid and are received by the receiver. In the absence of flow, the propagation time of the ultrasonic waves is constant because the speed of sound is constant in static fluid. However, when the fluid flows, the ultrasonic waves encounter flow resistance during propagation, resulting in a change in propagation time. According to the Doppler effect, the fluid flow causes a change in the frequency of the ultrasonic waves, thereby affecting the propagation time.

[0054] An ultrasonic time-of-flight flow meter calculates the flow rate and flow of fluid by measuring the difference in propagation time of ultrasonic waves. When an ultrasonic pulse is emitted from the transmitter, it propagates at a fixed speed in static fluid and then slows down due to flow resistance in the fluid. After the receiver receives the ultrasonic pulse, it records the difference in propagation time. Based on the speed of sound and the difference in propagation time, the flow rate of the fluid can be calculated. By measuring the cross-sectional area of the pipe, the flow rate of the fluid can be further calculated by the terminal. The flow meter usually also uses other sensors, such as temperature sensors and pressure sensors, to provide more accurate flow measurement results.

[0055] II. Symbol explanation: Reference Figure 12 In the imaging photo L1: the center line of the pipe to be detected; L2: a straight line passing through the center point A1 of the first alignment mark and the center point A2 of the second alignment mark; C1: the center point of the adjusting disc 54 of the first rotating part 51; C2: the center point of the adjusting disc 54 of the second rotating part 52; C3: the center point of the adjusting rod 55 of the first rotating part 51; C4: the center point of the adjusting rod 55 of the second rotating part 52; L10: the distance between C1 and C3, indicating the distance value of the center point of the adjusting disc 54 to the center point of the adjusting rod 55; L11: the distance value between C3 and C4, which is usually a fixed value, because A1 coincides with C3 and A2 coincides with C4 in the initial state, L11 is actually consistent with the distance between A1 and A2; L12: the straight line distance value between C1 and L1; A11: the included angle between L1 and L2, specifically the acute angle value with C3 as the intersection point after adjustment of the first rotating part 51.

[0056] III. Specific steps: S1, according to the diameter of the pipeline to be detected, the length of the straight rod part is set; to be precise, the distance between the center points of the two ultrasonic detectors in the first flow meter unit and the second flow meter unit should be set according to the diameter of the pipeline, so that the time difference method measurement is more accurate and reliable; S2, under the control of the control host, the unmanned aerial vehicle clamps and conveys the detection device through the hoisting mechanism; S3, the unmanned aerial vehicle conveys the detection device to the predetermined position of the pipeline to be detected, and places the detection part as much as possible above the center line of the pipeline; S4, the cleaning motor of the pipe wall cleaning unit drives the turntable and the rotating shaft to perform horizontal revolution, and the rotating shaft performs revolution around its center line under the action of the gear and the gear plate, so as to realize the cleaning operation of the pipeline to be detected, and when the turntable stops working, the first flow meter unit or the second flow meter unit is located between the adjacent rotating shaft and the bristle cleaning; S5, the unmanned aerial vehicle hovers above the detection device and the pipeline, and obtains an imaging photo including the first alignment mark and the second alignment mark of the detection device and the pipeline profile through the camera (for reference Figure 13 ); S6, in the imaging photo, the edge finding processing is performed on the pipeline profile, the edge lines on both sides of the pipeline are found, the sub-pixel edge detection operation is performed on the current imaging photo, the center line L1 of the pipeline is obtained after the edge lines on both sides are determined, the continuous line L2 passing through the center point A1 of the first alignment mark and the center point A2 of the second alignment mark is obtained, and the distance value L12 between A1 and L1 is calculated; if the value of L12 is greater than or equal to the set threshold value, which represents the range of allowable error (specifically, a value within 1mm), the angle value of moving A1 to L1 is calculated based on the value of L10 at the first rotating part, and then A1 is arranged on the line L1 through the first rotating part; S7 (for reference Figure 14 ), the angle value A11 between L1 and L2 is calculated with A1 point as the vertex, if the value of A11 is greater than or equal to the set threshold value, which also represents the range of allowable error (specifically, a value within 0.1 degrees), then the angle value of moving A2 to L1 is calculated based on the values of L11 and L10 at the second rotating part, and then A2 is arranged on the line L1 through the second rotating part, and L2 and L1 are in the state of coincidence, it should be noted that since the first mounting plate is a circular hole and the second mounting plate is an oblong hole, the rotation is always performed with C3 point as the center during the rotation; S8 in step S6, if the value of L12 is greater than the radius value L10 of the adjusting rod for the adjusting disc, or, in step S7, if the value of A11 is greater than the maximum value of the adjusting rod of the second rotating part for the adjusting disc, return to step S2; this return operation means that the alignment and coincidence operation of L1 and L2 cannot be achieved within the range that the first rotating part or the second rotating part can adjust, and the unmanned aerial vehicle needs to reposition the detection device; S9 (reference Figure 15 ) Control the host computer to control the first flowmeter unit and the second flowmeter unit to operate downward, release the ultrasonic detector by the servo cylinder, make it adhere to the outer wall of the pipeline under the action of gravity, open the elastic cover plate under pressure, and then obtain the wall thickness value of the current pipeline through the pipeline wall thickness detector. The first flowmeter unit and the second flowmeter unit detect the flow of the fluid in the pipeline according to the time difference method or the principle of Doppler effect, and finally obtain the flow rate value of the current pipeline liquid.

[0057] At this point, the unmanned aerial vehicle application type pipeline flow rate detection system completes the flow rate detection operation of the current pipeline, and then the first rotating part and the second rotating part are reversely rotated to restore to the initial state. The unmanned aerial vehicle clamps and transports the detection device, and can detect the next detection point.

[0058] It is also necessary to say that before the position adjustment, i.e. the coincidence operation of L2 and L1, the pipeline wall cleaning operation is carried out first, which can prevent the position of the detection device from being changed after alignment due to cleaning operation, thereby affecting the detection accuracy.

[0059] In summary, the unmanned aerial vehicle application type pipeline flow rate detection system provides a pipeline flow rate detection system which adopts an unmanned aerial vehicle and a detection device. The detection device can be placed in various unconventional pipelines, such as rivers, high buildings or complex fields, by the unmanned aerial vehicle. The operator can control remotely and continuously work at multiple detection points according to the set cruise route, which reduces the operation difficulty and risk and improves the detection efficiency. The present scheme is implemented by the cooperation of the unmanned aerial vehicle and the detection device. In conventional manual detection, the equipment needs to be placed and aligned by hand. However, in narrow and uneven pipelines, the placement and alignment may not be accurate enough, which may cause detection errors. In the present scheme, the entire arrangement structure is photographed by the imaging of the camera of the unmanned aerial vehicle, and the detection part can be accurately placed above the center line of the pipeline through the position adjustment function of the detection device, so that the detection accuracy can be greatly improved. The detection device of the scheme integrates the detection mechanism, the cleaning mechanism and the position adjusting mechanism, resolves the defects of multiple works such as cleaning and alignment required by traditional manual operation, and greatly improves the manual strength of outdoor detection work. The method for accurately arranging the detection device calculates the distance and angle relationship between the pipeline center line L1 and the detection device center line L2 through photographing and imaging. When the deviation is within a controllable range, the first rotating part and the second rotating part can work cooperatively to make L1 and L2 in the accurate alignment state, so that the accuracy of the detection operation can be ensured.

Claims

1. A UAV-based pipeline flow velocity detection system, characterized in that: include: The detection device has a horizontally arranged straight rod component. A first flow meter unit and a pipe wall thickness detector are arranged at one end of the straight rod component, and a second flow meter unit is arranged at the other end. A first alignment mark and a second alignment mark are arranged on the upper surface of the straight rod component. The line connecting the center points of the first alignment mark and the second alignment mark and the center line of the straight rod component are arranged parallel to each other in the vertical plane. The drone has a flight structure and flight control system, and has at least one camera capable of imaging vertically downwards, and a hoisting mechanism for connecting the detection device; The control host operates and controls the drone and detection device via wired or wireless means, and acquires image information fed back by the drone's camera; The bottom hoisting mechanism of the drone includes a clamping component that can restrict the straight rod component and arrange the centerline of the straight rod component in a parallel direction with the centerline of the drone.

2. The UAV-based pipeline flow velocity detection system according to claim 1, characterized in that: The straight rod component includes a front rod and a rear rod, which are capable of telescopic length adjustment in a center-aligned manner. The first flow meter unit is arranged at the front end of the front rod, and the second flow meter unit is arranged at the rear end of the rear rod. The bottoms of the first flow meter unit and the second flow meter unit are arranged horizontally aligned.

3. The UAV-based pipeline flow velocity detection system according to claim 2, characterized in that: Pipe wall cleaning units are arranged at the front end of the front rod and the rear end of the rear rod. The pipe wall cleaning units are configured to clean the outer wall of the pipe to be tested. The first flow meter unit and the second flow meter unit are arranged above the corresponding pipe wall cleaning units.

4. The UAV-based pipeline flow velocity detection system according to claim 3, characterized in that: The pipe wall cleaning unit includes a cleaning motor, which is vertically arranged and fixedly installed at the bottom of the outer end of the front or rear rod. A turntable is arranged at the front end of the cleaning motor, and three rotating shafts are arranged in a central array along the outer edge of the turntable. The rotating shafts and the turntable are rotatably connected by bearings. Brush bristles are installed on the rotating shafts, and gears are arranged on the outer side of the rotating shafts connected to the turntable. A gear ring is fixedly arranged at the bottom of the front or rear rod, and the gear ring is arranged in a center-aligned manner with the turntable. The tops of all gears are engaged with the gear rings.

5. The UAV-based pipeline flow velocity detection system according to claim 4, characterized in that: The rotating shaft is arranged in a spiral structure with metal wire bristles, plastic wire bristles and flexible spiral blades spaced apart, and the outer diameters of the plastic wire bristles, metal wire bristles and flexible spiral blades decrease sequentially.

6. The UAV-based pipeline flow velocity detection system according to claim 2, characterized in that: The bottom of the front rod is provided with an alignment adjustment mechanism, which is used to adjust the position and angle of the straight rod component on the pipe.

7. The UAV-based pipeline flow velocity detection system according to claim 6, characterized in that: The alignment adjustment mechanism includes a first rotating component located at the rear end of the front rod and a second rotating component located at the front end of the front rod. Both the first and second rotating components include an alignment motor connected to a reducer. An adjustment disc is connected to the rear end of the reducer, and the alignment motor drives the adjustment disc to rotate. An adjustment rod is vertically arranged at an eccentric position on the adjustment disc. A first mounting plate is arranged on the top of the first rotating component and is fixedly installed to the bottom of the front rod. The first mounting plate has a circular through hole through which the adjustment rod passes. An end plate is provided on the top of the adjustment rod, and the circular through hole and the adjustment rod are in close contact. The second rotating component has a similar structure to the first rotating component. A second mounting plate is arranged on the top of the second rotating component and is fixedly installed to the bottom of the front rod. An elongated hole is provided on the second mounting plate through which the adjustment rod passes. An end plate is provided on the top of the adjustment rod, and the elongated hole and the adjustment rod are in close contact. The adjustment rod of the second rotating component can move horizontally at the elongated hole. The center point of the first alignment mark and the center point of the circular through hole are aligned vertically.

8. The UAV-based pipeline flow velocity detection system according to claim 1, characterized in that: The first flow meter unit or the second flow meter unit includes a straight cylinder, and an ultrasonic detector is arranged inside the straight cylinder. The probe of the ultrasonic detector is arranged at the center of the straight cylinder. The ultrasonic detector is in a sliding arrangement inside the straight cylinder. An elastic cover plate is arranged at the bottom of the straight cylinder. The side wall of the straight cylinder is provided with a vertical groove and a slider. The slider is connected to the drive end of a servo electric cylinder. A pipe wall thickness detector is arranged inside the straight cylinder of the first flow meter unit next to the ultrasonic detector.

9. A method for precisely arranging detection devices, applied to the UAV-based pipeline flow velocity detection system as described in any one of claims 1 to 8, characterized in that: Includes the following steps: S1 sets the length of the straight rod component based on the diameter of the pipe to be inspected; S2 Under the control of the host computer, the UAV clamps and transports the detection device through the hoisting mechanism; The S3 drone delivers the detection device to the predetermined position of the pipeline to be inspected, and places the detection component as close as possible to the center line of the pipeline; The cleaning motor of the S4 pipe wall cleaning unit drives the turntable and the rotating shaft to rotate horizontally. Under the action of gears and toothed discs, the rotating shaft rotates around its own center line to achieve the cleaning operation of the pipe to be inspected. When the turntable stops working, the first flow meter unit or the second flow meter unit is positioned between the adjacent rotating shaft and the brush. The S5 drone hovers directly above the inspection device and pipeline, and uses a camera to capture images including the first and second alignment marks of the inspection device and the outline of the pipeline. S6 performs edge-finding processing on the pipe outline in the image. By finding the edge lines on both sides of the pipe, after determining the edge lines on both sides, the center line L1 of the pipe is obtained. Similarly, L2 is obtained by continuously passing the center point A1 of the first alignment mark and the center point A2 of the second alignment mark, and the distance value L12 between A1 and L1 is calculated. If the value of L12 is greater than or equal to a set threshold, at the first rotating component, based on the value of L10, the angle value for moving A1 to L1 is calculated, and then A1 is arranged on the line L1 by the first rotating component. S7 uses point A1 as the vertex to calculate the angle value A11 between L1 and L2. If the value of A11 is greater than or equal to the set threshold, then at the second rotating component, based on the values ​​of L11 and L10, the angle value for moving A2 to L1 is calculated. Then, the second rotating component is used to arrange A2 on line L1, and L2 and L1 are made to coincide. The S8 control host controls the first and second flow meter units to move downwards, and based on their own gravity, their lower ends are made to fit tightly against the outer wall of the pipe. Then, the pipe wall thickness is obtained by the pipe wall thickness detector. The first and second flow meter units detect the flow rate of the fluid in the pipe based on the time difference method or the Doppler effect principle, and obtain the current flow velocity value of the liquid in the pipe.

10. A method for precisely arranging a detection device according to claim 9, characterized in that: In step S6, if the value of L12 is greater than the radius of the adjusting rod relative to the adjusting disk, or in step S8, if the value of A11 is greater than the maximum adjustable value of the adjusting rod of the second rotating component relative to the adjusting disk, then return to step S2.

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