Aerial manipulator system for measuring depth of cracks in substructure of reinforced concrete bridge

Abstract

Disclosed in the present invention is an aerial manipulator system for measuring the depth of cracks in the substructure of a reinforced concrete bridge, the system comprising a main human-computer interface device, an aerial manipulator, and an end effector, wherein the main human-computer interface device comprises a remote controller and a control computer; the aerial manipulator comprises a drone and a single-degree-of-freedom robotic arm; and the end effector comprises an ultrasonic crack depth measurement mechanism, a shock absorber and a force sensor. In the present invention, the aerial manipulator system is designed to be able to stably contact the substructure of a reinforced concrete bridge and automatically complete crack depth measurement procedures, thereby reducing the high-altitude operation risk and workload of bridge inspectors, and improving the efficiency of crack depth measurement operations.

Description

Flying robotic arm system for crack depth measurement in reinforced concrete bridge substructures Technical Field

[0001] The present invention relates to the field of flying robotic arms, and in particular to a flying robotic arm system and an operating method for detecting crack depths in a reinforced concrete bridge substructure. Background Art

[0002] Bridge crack detection is an important task in bridge operation and maintenance. Cracks are a common disease in bridge structures. If not discovered and treated in a timely manner, they may lead to damage to the bridge structure and collapse accidents. At present, there are some mature methods for detecting the length and width of cracks, such as manual measurement using tools (such as rulers and laser rangefinders) and shooting with drones, and calculating the length of the cracks by using image processing algorithms. However, the depth detection of cracks mainly relies on manually carried non-destructive testing instruments, which has high safety risks and low operating efficiency, especially for bridge substructures. The solution that combines ultrasonic crack depth measuring devices with flying operating arms has the advantages of safety and efficiency. It can greatly reduce the risks and workload of bridge inspection personnel working at heights and improve work efficiency.

[0003] Summary of the Invention

[0004] Technical problem: To solve the above-mentioned problems, in view of complex working environments and detection tasks, the present invention provides a flying robotic arm system for crack depth measurement in reinforced concrete bridge substructures by designing a mechanism that automatically adjusts the robotic arm angle and the end transducer spacing according to the situation. This can reduce the operator's workload and improve the efficiency of crack depth measurement.

[0005] Technical Solution: A flying robotic arm system for crack depth measurement in reinforced concrete bridge substructures, characterized by comprising a master-end human-machine interface device, a flying robotic arm, and an end effector, wherein the master-end human-machine interface device includes a remote controller and a control computer; the flying robotic arm includes a steering gear and a single-degree-of-freedom robotic arm; and the end effector includes an ultrasonic crack depth measurement mechanism, a shock absorber, and a force sensor. Operation of the system includes the following steps:

[0006] Step 1: The operator controls the drone to take off and hover at the far end of the bridge substructure. The onboard camera on the aircraft identifies the crack location, sends the relative spatial coordinates to the onboard computer, and automatically flies the drone close to the crack location.

[0007] Step 2: The operator takes over control of the drone and uses the transmitted image information to slowly move the drone forward and hover over one side of the crack;

[0008] Step 3: The drone moves forward slowly. After the end effector contacts the surface to be measured, the angle of the robotic arm joint is automatically adjusted according to the data sent back by the force sensor. The shock absorber is used to achieve stable contact with the crack position, completing the first non-crack-crossing measurement.

[0009] Step 4: After the drone breaks contact, the ultrasonic crack depth measurement mechanism automatically adjusts the distance between the end plane transducers. The same operation is performed to complete a total of three non-crack measurements.

[0010] Step 5: Adjust the position of the drone so that it faces the crack, complete two cross-crack measurements, and finally transmit the measured data back to the main control computer to calculate the crack depth value, completing the crack depth measurement task;

[0011] The camera in step 1 identifies the crack location through an image algorithm, calculates the relative position of the crack with the help of the camera's depth map, and sends it to the drone to achieve flight towards the crack location; the shock-absorbing device in step 3 is connected to the front ultrasonic depth probe. At the moment of contact with the crack, the spring absorbs the forward kinetic energy of the drone and gradually slows the drone down to keep it relatively stationary with the bridge; the force sensor in step 3 transmits data back to the onboard computer in real time, and uses the PID algorithm to automatically adjust the angle of the robotic arm to track the reference force F tar The stepper motor in the ultrasonic crack depth measurement mechanism of step 4 automatically adjusts the spacing of the end plane transducer three times according to the signal from the remote control. The spacing of the three adjustments is 50mm, 100mm and 150mm respectively. The calculation of the crack depth information in step 5 adopts the single-side flat measurement method. The ultrasonic wave propagates in the crack test block and completes the reading process by detecting two crack measuring points at different detection distances. Assuming that the sound time value of the i-th detection in the three non-cross-crack detections is The acoustic duration of the jth detection in two cross-slit detections is Define S1 = 50mm, S2 = 100mm, S3 = 150mm; use regression analysis to find the regression line equation between the sound time t and the distance S for non-slit detection: S = a + bt

[0012] At this time, the concrete sound velocity value v of the non-cross-joint horizontal measurement is b; the crack depth value h calculated by the i-th cross-joint detection is i The calculation formula is as follows:

[0013] The final average crack depth value h avg The calculation formula is as follows:

[0014] The beneficial effects of the present invention are: a flying robotic arm system is designed that can stably contact the lower structure of a reinforced concrete bridge and automatically complete the crack depth detection process, thereby reducing the high-altitude working risks and workload of bridge inspection personnel and improving the efficiency of crack depth measurement operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG1 is a schematic diagram of a system of the present invention;

[0016] Figure 2 is an overall schematic diagram of the flight manipulator and the end effector;

[0017] Figure 3 is a schematic diagram of the terminal shock absorption mechanism;

[0018] Figure 4 is a schematic diagram of the terminal depth sounding mechanism;

[0019] Figure 5 is a schematic diagram of crack distance measurement and crack depth;

[0020] FIG6 is a schematic diagram of a stable contact working process of the present invention;

[0021] FIG7 is a schematic diagram of the crack depth measurement workflow of the present invention;

[0022] FIG8 is a schematic diagram of the present invention when it is working.

[0023] List of Figure Symbols: 1. Remote control; 2. Main control computer; 3. UAV; 3-1. Onboard camera; 3-2. Single-degree-of-freedom robotic arm; 3-3. Servo; 3-4. Battery; 3-5. Landing gear; 3-6. Onboard computer; 4. End effector; 4-1. Force sensor; 4-2. Spring; 4-3. Screw; 4-4. Stepper motor; 4-5. Planar transducer; 4-6. Screw stabilizer; DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0025] As shown in FIG1 , the flying manipulator system for measuring crack depth in reinforced concrete bridge substructures includes a master-end human-machine interface device, a flying manipulator 3 , and an end effector 4 . The master-end human-machine interface device includes a remote controller 1 and a main control computer 2 .

[0026] As shown in FIG2 , the flight manipulator 3 has an onboard camera 3-1 mounted in the middle of a single-degree-of-freedom manipulator 3-2. The angle is adjusted by a servo 3-3. During flight, the battery 3-4 provides energy, the onboard computer 3-6 performs computing tasks, and the landing is completed by the landing gear 3-5.

[0027] As shown in FIG3 , the shock absorbing mechanism is composed of a force sensor 4 - 1 and a spring 4 - 2 ;

[0028] As shown in Figure 4, the end depth sounding mechanism is composed of two stepper motors 4-4 that rotate a specified number of times according to the instructions of the onboard computer. The two screw rods 4-3 are driven by the stepper motors to control the spacing between the two planar transducers 4-5. The ends of the two screw rods are supported by screw rod stabilizers 4-6, but are not connected.

[0029] The operation of the system comprises the following steps:

[0030] Step 1: The operator uses the remote control 1 to control the drone 3 to take off and hover at the far end of the bridge substructure. The onboard camera 3-1 of the drone 3 identifies the crack location, sends the relative spatial coordinates to the onboard computer 3-6, and automatically makes the drone 3 approach the crack location;

[0031] Step 2: The operator takes over the operation of the drone 3 and controls the drone to slowly move forward and hover on one side of the crack using the image information sent back by the onboard computer 3-6;

[0032] Step 3: The drone 3 moves forward slowly. After it contacts the surface to be measured, it automatically adjusts the steering gear 3-3 based on the data sent back by the force sensor 4-1 to control the inclination angle of the robotic arm, and uses the shock-absorbing spring device 4-2 to achieve stable contact with the crack position.

[0033] Step 4: After the UAV breaks away from contact, the stepper motor 4-4 in the ultrasonic crack depth measurement mechanism 4 automatically adjusts the distance between the end plane transducers 4-5 three times to complete the non-crossing crack measurement;

[0034] Step 5: Adjust the position of the drone 3 so that it faces the crack, complete two cross-crack measurements, and finally transmit the measured data back to the main control computer 2 to calculate the crack depth value, completing the crack depth measurement task.

[0035] The technical means disclosed in the solutions of the present invention are not limited to those disclosed in the above-mentioned embodiments, but also include technical solutions composed of any combination of the above-mentioned technical features. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A flying robot arm system for measuring crack depth in reinforced concrete bridge substructure, characterized in that: The system comprises a main-end human-machine interface device, a flight mechanical arm and an end effector, wherein the main-end human-machine interface device comprises a remote controller and a control computer; the flight mechanical arm comprises a drone and a single-degree-of-freedom mechanical arm; the end effector comprises an ultrasonic crack depth measurement mechanism, a shock absorbing device and a force sensor; the operation of the system comprises the following steps: Step 1: The operator controls the drone to take off and hover at the far end of the bridge substructure. The onboard camera carried by the aircraft identifies the crack location, sends the relative spatial coordinates to the onboard computer, and makes the drone automatically fly close to the crack location; Step 2: The operator takes over the control of the drone and uses the image information sent back to control the drone to slowly move forward and hover on one side of the crack; Step 3: The drone moves forward slowly. After the end effector contacts the surface to be measured, the angle of the robot arm joint is automatically adjusted according to the data sent back by the force sensor. With the help of the shock-absorbing device, the robot achieves stable contact with the crack position, thus realizing the first non-cross-crack measurement. Step 4: After the drone breaks away from contact, the ultrasonic crack depth measurement mechanism automatically adjusts the spacing of the end plane transducers, and the same operation is performed to complete a total of three non-cross-crack measurements; Step 5: Adjust the position of the drone so that it faces the crack, complete two cross-crack measurements, and finally transmit the measured data back to the main control computer to calculate the crack depth value, thus completing the crack depth measurement task.

2. The flying mechanical arm system for measuring crack depth of reinforced concrete bridge substructure according to claim 1 is characterized in that: The camera in step 1 identifies the crack position through an image algorithm, calculates the relative position of the crack with the help of the depth map of the camera, and sends it to the drone to achieve flight to the crack position.

3. The flying robot arm system method for measuring crack depth of reinforced concrete bridge substructure according to claim 1 is characterized in that: The shock absorbing device in step three is internally connected to the front ultrasonic depth measuring probe, and absorbs the forward kinetic energy of the drone through the spring at the moment of contact with the crack, and gradually slows down the drone.

4. The flying robot arm system method for measuring crack depth of reinforced concrete bridge substructure according to claim 1, characterized in that: The force sensor in step 3 transmits data back to the onboard computer in real time, and uses the PID algorithm to automatically adjust the angle of the robotic arm to track the reference force F. tar ;.

5. The flying robot arm system method for measuring crack depth of reinforced concrete bridge substructure according to claim 1, characterized in that: The stepper motor in the ultrasonic crack depth measurement mechanism of step 4 automatically adjusts the spacing of the end plane transducers three times according to the signal transmitted by the remote control, and the three adjusted spacings are 50mm, 100mm and 150mm respectively.

6. The flying robot arm system method for measuring crack depth of reinforced concrete bridge substructure according to claim 1, characterized in that: The calculation of crack depth information in step 5 adopts the single-sided flat measurement method. The ultrasonic wave propagates in the crack test block and completes the reading process by detecting two crack measuring points at different detection distances. Assuming that the acoustic time value of the i-th detection in three non-cross-crack detections is The acoustic duration of the jth detection in two cross-slit detections is Define S1 = 50mm, S2 = 100mm, S3 = 150mm; use regression analysis to find the regression line equation between the sound time t and the distance S for non-slit detection: S = a + bt At this time, the concrete sound velocity value v of the non-cross-joint horizontal measurement is b; the crack depth value h calculated by the i-th cross-joint detection is i The calculation formula is as follows: The final average crack depth value h avg The calculation formula is as follows:

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