CN105302141B - Omnidirection movement radiographic source end robot method for synchronized based on Mecanum wheels - Google Patents

Abstract

The present invention provides a method for synchronous tracking of omni-directional mobile ray source end robots based on Mecanum wheels. The ray source end robots walk autonomously and record encoder information to obtain the number of rotations of each wheel, and then send the information wirelessly to Robot at the digital flat panel detector side; the robot at the digital flat panel detector side controls the rotation of each wheel of the robot at the digital flat panel detector side according to the encoder information sent by the robot at the ray source side, and eliminates the cumulative error generated by the movement of the robot at the digital flat panel detector side. It can realize the synchronous walking of the robot at the ray source end and the robot at the digital flat panel detector end, and make the synchronization between the robot at the ray source end and the robot at the digital flat panel detector end more accurate by eliminating the cumulative error generated by the movement of the robot at the digital flat panel detector end.

Description

Synchronous Tracking Method of Omni-directional Mobile Ray Source Robot Based on Mecanum Wheel

technical field

The invention relates to a method for synchronous tracking of an omnidirectional mobile ray source end robot based on a Mecanum wheel.

Background technique

my country is a big country in the manufacture of pressure-bearing special equipment, and the number of pressure-bearing special equipment manufacturing ranks first in the world. Pressure-bearing special equipment is the basic equipment of industry. Petrochemical, electric power, aerospace and other industries, as well as various fields of national defense and people's livelihood require various pressure-bearing special equipment. It is of strategic significance to improve the international competitiveness, manufacturing capacity and product quality of my country's pressure-bearing special equipment.

Non-destructive testing is a key means to check the quality of pressure-bearing special equipment manufacturing, and it is also a bottleneck restricting production capacity. At present, in the manufacture of special pressure equipment in China, film radiography is used for 70% of non-destructive testing of welds. This method has a long detection period, low efficiency, difficulty in image storage and reproduction, and consumes a large amount of oil and silver resources, and also produces darkroom waste liquid to pollute the environment, so it is urgently needed to be improved and improved.

Digital flat panel radiography is a new non-destructive testing technology developed in the past ten years. It has the advantages of fast detection speed, high efficiency, high sensitivity, convenient image storage, copying and calling, energy saving and environmental protection, etc. However, since the digital flat-panel detector of digital flat-panel radiography cannot be attached to the inner wall of the container like a film, this technology cannot be applied in the inspection of medium-to-large-diameter container welds by single-wall transillumination. At present, only double-wall can be used. The transillumination method is used to detect the weld seams of pipes and gas cylinders with a diameter of less than 1m.

In recent years, the number of special equipment has been increasing rapidly. This poses new challenges to ensure high-quality, high-efficiency, and high-level inspection and testing of special equipment. At present, there is a gap in the automated digital ray inspection process equipment for large-scale spherical tanks, vertical storage tanks and other in-service pressure-bearing special equipment at home and abroad, and the existing inspection robots are relatively insufficient in flexibility for weld inspection on equipment curved surfaces. need.

For example, the detection robot disclosed in the patent No. ZL200510018933.4 cannot detect large spherical tanks and vertical storage tanks because they cannot be positioned on the object to be detected.

For example, the X-ray detection robot for storage tank welds disclosed in the application number 201410005169.6 can only move horizontally and vertically, and cannot move or rotate in any direction. position.

Pressure-bearing special equipment involves public safety, has high quality requirements, and needs advanced non-destructive testing technology to escort. We should improve the manufacturing capacity and quality level of pressure-bearing special equipment, and at the same time improve the level of non-destructive testing technology in my country.

Contents of the invention

The purpose of the present invention is to provide a method for synchronous tracking of an omnidirectional moving ray source end robot based on a Mecanum wheel to solve the relatively accurate synchronous movement of a ray emitting robot and an imaging robot to ensure effective imaging and the like.

Technical solution of the present invention is:

A method for synchronous tracking of omnidirectional mobile ray source robot based on Mecanum wheel,

The robot at the ray source end walks autonomously, and records the encoder information to obtain the number of rotations of each wheel, and then sends this information to the robot at the digital flat panel detector end through wireless;

The robot at the digital flat panel detector side controls the rotation of each wheel of the robot at the digital flat panel detector side according to the encoder information sent by the robot at the ray source side, and eliminates the cumulative error generated by the movement of the robot at the digital flat panel detector side.

Further, eliminate the cumulative error generated by the robot movement at the digital flat panel detector end, specifically:

The exposure area on the digital panel is obtained from the picture obtained by each digital flat panel exposure, and the exposure area is the position of the radiation source, that is, the offset distance of the robot at the digital flat panel detector end relative to the robot at the radiation source end is obtained through the picture, and is shown in the following During a walking process, the motion of the robot at the digital flat panel detector end is corrected to realize the synchronization between the robot at the digital flat panel detector end and the robot at the ray source end.

Further, eliminate the cumulative error generated by the robot movement at the digital flat panel detector end, specifically:

The robot at the ray source end is equipped with a resistance wire. The robot at the ray source end heats the tank body area facing the heat source through the resistance wire or infrared rays. Characteristic of a gradual decrease in temperature;

The robot on the digital flat-panel detector end has four symmetrical thermal sensors. The temperature difference between the four thermal sensors will generate a piezoelectric signal. If there is no alignment, the four thermal sensors will Different temperatures will cause a pressure difference in the generated piezoelectric signal. According to the pressure difference, the robot at the digital flat panel detector end is controlled to move toward the highest temperature point to realize the synchronization between the robot at the digital flat panel detector end and the robot at the ray source end.

Further, the ray source robot includes frame one, Mecanum wheel one, servo motor one, front tracking sensor one, rear tracking sensor one, X-ray source, permanent magnet one and motion control box one, motion control box one Set on the vehicle frame one, the front tracking sensor one is located at the front end of the vehicle frame one, the rear tracking sensor one is located at the rear end of the vehicle frame one, the middle part of the vehicle frame one is provided with an X-ray source, and the two sides of the vehicle frame one Mecanum wheel 1 is respectively arranged on the side, and Mecanum wheel 1 is connected with servo motor 1, and servo motor 1 is connected with motion control box 1, and the bottom two sides of vehicle frame 1 are respectively provided with permanent magnet 1.

Further, the digital flat panel detector end robot includes frame two, Mecanum wheel two, servo motor two, front tracking sensor two, rear tracking sensor two, digital flat panel, permanent magnet two and motion control box two, motion control box The second is located on the frame two, the front tracking sensor two is located at the front end of the vehicle frame two, the rear tracking sensor two is located at the rear end of the vehicle frame two, the middle part of the vehicle frame two is provided with a digital panel, and the digital panel is located on the vehicle frame The bottom of the frame 2 and the two sides of the frame 2 are respectively equipped with Mecanum wheels 2, the Mecanum wheels 2 are connected with the servo motor 2, the servo motor 2 is connected with the motion control box 2, and the bottom sides of the frame 2 are respectively provided with permanent magnets 2 .

Further, the number of the first Mecanum wheel and the second Mecanum wheel is four, the first Mecanum wheel is respectively provided at the four ends of the frame one, and the second Mecanum wheel is respectively arranged at the four ends of the second frame.

Further, the robot at the ray source end and the robot at the digital flat panel detector end are respectively arranged on both sides of the detected object.

Further, a WiFi repeater is provided at the entrance and exit of the detected object.

Further, the first frame and the second frame are square structures formed by vertically setting several longitudinal ribs and several transverse ribs.

Further, between the permanent magnet one and the detected object, between the permanent magnet two and the detected object, gaps are respectively provided, that is, the bottom surface of the permanent magnet one is higher than the bottom surface of the Mecanum wheel one, and the bottom surface of the permanent magnet two is higher than the bottom surface of the Mecanum wheel one. The bottom surface is higher than the bottom surface of Mecanum wheel two; the distance between permanent magnet one and the detected object is greater than the distance between Mecanum wheel one and the detected object, and the distance between permanent magnet two and the detected object is greater than that of Mecanum wheel two and the detected object distance.

The beneficial effects of the present invention are: the method for synchronous tracking of the robot at the omnidirectional mobile ray source end based on the Mecanum wheel can realize the synchronous walking of the robot at the ray source end and the robot at the digital flat panel detector end, and by eliminating the The cumulative error generated by the motion makes the synchronization between the robot at the ray source end and the robot at the digital flat panel detector more precise, so that when the robot at the ray source end and the robot at the digital flat panel detector end move and detect in all directions on the spherical tank, digital The effective imaging of the digital flat panel on the robot at the flat panel detector side ensures the smooth progress of the inspection and the flexibility and accuracy of the robot's inspection of internal welds such as spherical tanks.

Description of drawings

Fig. 1 is the structural representation of the embodiment of the present invention;

Fig. 2 is a schematic structural diagram of the ray source end robot in the embodiment;

Fig. 3 is the structural representation of digital flat panel detector end robot in the embodiment;

Fig. 4 is a schematic diagram of the connection relationship between the suspension vibration isolation device and the vehicle frame 1 in the embodiment;

Fig. 5 is a schematic structural view of the suspension vibration isolation device in the embodiment;

Fig. 6 is a top view of the suspension vibration isolation device in the embodiment;

Figure 7 is a rear view of the suspension vibration isolation device in the embodiment;

Fig. 8 is a right view of the suspension vibration isolation device in the embodiment;

Fig. 9 is a schematic diagram of the communication connection between the robot at the radiation source end, the robot at the digital flat panel detector end, and the host computer in the embodiment;

Fig. 10 is a schematic diagram illustrating the process of synchronous tracking of the robot at the ray source end and the robot at the digital flat panel detector end in the embodiment;

Fig. 11 is the explanatory diagram of detection report generating module in the embodiment;

Among them: 1-ray source robot, 2-digital flat panel detector robot, 3-host computer, 4-spherical tank, 5-suspension vibration isolation device;

11- Front tracking sensor 1, 12- Permanent magnet 1, 13- Mecanum wheel 1, 14- Frame 1, 15- Rear tracking sensor 1, 16- Servo motor 1, 17- X-ray source, 18- Movement control box one;

21-front tracking sensor 2, 22-permanent magnet 2, 23-Mecanum wheel 2, 24-frame 2, 25-rear tracking sensor 2, 26-servo motor 2, 27-digital panel, 28-motion control box two;

51-flexible unit, 52-motor fixed plate, 53-bearing seat, 54-wheel axle, 55-H type connecting rod, 56-vehicle frame fixing seat, 57-magnet fixing seat, 58 pressing plate.

Detailed ways

Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

Example

A digital flat-panel radiation detection system based on the Mecanum wheel, as shown in Figure 1, includes a host computer 3, a radiation source robot 1, and a digital flat-panel detector robot 2, and both the radiation source robot 1 and the digital flat-panel detector robot 2 use All-round Mecanum wheel structure, the ray source robot 1 is equipped with a motion control box 18, the motion control box 18 is connected with the upper computer 3 and the digital flat panel detector robot 2 through the wireless communication module 1, and the motion control box 18 is connected through CAN The communication module 1 is connected to the servo motor 1 16, and the robot 2 at the digital flat panel detector end is equipped with a motion control box 2 28, which is connected with the upper computer 3 and the ray source robot 1 through the wireless communication module 2, and the motion control box 2 28 is connected to the servo motor 2 26 through the CAN communication module 2.

The ray source robot 1 includes a vehicle frame 14, a Mecanum wheel 13, a servo motor 16, a front tracking sensor 11, a rear tracking sensor 15, an X-ray source 17, a permanent magnet 12 and a motion control box 1 18, as shown in Figure 2, the front tracking sensor one 11 is located at the front end of the vehicle frame one 14, the rear tracking sensor one 15 is located at the rear end of the vehicle frame one 14, and the middle part of the vehicle frame one 14 is provided with a motion control box one 18 And X-ray source 17, the both sides of vehicle frame-14 are respectively provided with Mecanum wheel-13, and Mecanum wheel-13 is connected with the rotating shaft of servomotor-16, and the bottom both sides of vehicle frame-14 is respectively provided with permanent magnet-12 .

Digital flat panel detector end robot 2 includes frame two 24, Mecanum wheel two 23, servo motor two 26, front tracking sensor two 21, rear tracking sensor two 25, digital flat panel 27, permanent magnet two 22 motion control box one 28, as shown in Figure 3, the front tracking sensor 2 21 is located at the front end of the vehicle frame 24, the rear tracking sensor 2 25 is located at the rear end of the vehicle frame 24, and the middle part of the vehicle frame 24 is provided with a motion control box 2 28 And digital flat panel 27, digital flat panel 27 is located at the bottom of vehicle frame two 24, and the both sides of vehicle frame two 24 are respectively provided with Mecanum wheel two 23, and Mecanum wheel two 23 is connected with the rotating shaft of servomotor two 26, and vehicle frame two 24 Two permanent magnets 22 are respectively arranged on both sides of the bottom.

The X-ray source 17 adopts a continuous X-ray source 17. Compared with a pulsed X-ray source, it can obtain clearer and higher-level imaging, and can make the detection image reach JB/T 4730.2-2005: AB level, which can be applied to bearing Internal defect detection of welding seam of pressure special equipment. For example: For a steel workpiece with a thickness of 25mm, use an image quality meter: IQI EN 462-W6 FE, AB level technical level requirements: No. 11 wire wire is clearly visible, and use a continuous X-ray source 17 to meet the technical level AB level requirements. The pulsed X-ray source has a low technical level and cannot meet JB/T 4730.2-2005: AB level. Generally, it cannot meet the needs of internal defect detection of welds in pressure-bearing special equipment. It is mainly used for metal hazards in airports and high-speed rail station security inspections. Automated scanning of products.

The embodiment adopts the single-wall transillumination shown in Fig. 1, the ray source is inside, and the digital flat panel is outside. Two carrying robot trolleys are magnetically adsorbed on the surface of the spherical tank 4. The two robots are divided into a ray source end robot 1 and a digital flat panel detector. The end robot 2 and the ray source end robot 1 are controlled by their own welding seam tracking or remote control, and the digital flat panel detector end robot 2 tracks the ray source end robot 1 to ensure that the digital flat panel detector end robot 2 and the ray source end robot 1 synchronized walking.

As shown in Figure 10, the robot 1 at the ray source end walks autonomously, and records the encoder information to obtain the number of turns of each wheel, and then sends the information to the robot 2 at the digital flat panel detector end through wireless, and the digital flat panel detector end robot 2 Robot 2 controls the rotation of each wheel of robot 1 at the digital flat panel detector end according to the encoder information sent by robot 1 at the ray source end, and the elimination of the cumulative error generated by the movement of robot 2 at the digital flat panel detector end can adopt two schemes:

Option 1, from the pictures obtained by each digital flat panel 27 exposure, it can be seen that there is a circular exposure area on the square digital flat panel 27, and the circular exposure area is the position of the radiation source, that is, the digital flat panel detector end is obtained through the picture. The position of robot 2 relative to the robot 1 at the ray source end is offset by a distance, and the movement of the robot 2 at the flat panel detector end is corrected during the next walking process, so as to realize the synchronization between the robot 2 at the digital flat panel detector end and the robot 1 at the ray source end track.

Solution 2, the robot 1 at the ray source end is equipped with a resistance wire, and the robot 1 at the ray source end heats the tank body area facing the heat source through the resistance wire or infrared rays. When the heating reaches a certain level, the heated area will form a point facing the heat source The temperature is the highest, and the temperature gradually decreases towards the surroundings. The robot 2 at the digital flat panel detector side is distributed with four symmetrical thermal sensors. The temperature difference between the four thermal sensors will generate a piezoelectric signal. If there is no alignment In the case of the four thermal sensors facing different temperatures, there will be a pressure difference in the piezoelectric signal generated. According to the pressure difference, the robot at the end of the digital flat panel detector is controlled to move towards the highest temperature point, thereby realizing synchronous tracking.

The kinematic structure of each robot adopts an all-round Mecanum wheel structure, that is, Mecanum wheels are used in more than three positions of the robot, that is, Mecanum wheels, preferably four positions. The omnidirectional mobile robot based on four Mecanum wheels is magnetically adsorbed on the surface of the spherical tank 4, and carries a digital ray inspection system to inspect the weld. The omnidirectional mobile robot can flexibly inspect welds in various directions. Wherein, the adsorption of the robot on the surface of the spherical tank 4 is realized by installing four permanent magnets on the vehicle frame and arranging them symmetrically.

The bottom surface of permanent magnet one 12 is higher than the bottom surface of Mecanum wheel one 13, and the bottom surface of permanent magnet two 22 is higher than the bottom surface of Mecanum wheel two 23, so that permanent magnet one 12 and permanent magnet two 22 can provide While maintaining the adsorption force, keep a certain distance from the wall of the spherical tank to avoid too much resistance from affecting the walking during complete adsorption, so as to ensure the smooth walking of Mecanum wheel 13 and Mecanum wheel 2 23. The first permanent magnet 12 and the second permanent magnet 22 can also adopt a reversible structure, and by adjusting the adsorption angles of the first permanent magnet 12 and the second permanent magnet 22, the adjustment of different adsorption forces can be realized.

The front tracking sensor one 11 and the rear tracking sensor one 15 are respectively connected to the motion control box one 18, and the motion control box one 18 is connected with the upper computer 3 through the wireless WIFI module. The front tracking sensor 2 21 and the rear tracking sensor 2 25 are respectively connected to the motion control box 2 28, and the motion control box 2 28 is connected to the upper computer 3 through the wireless WIFI module. The welding seam tracking of robot 1 at the ray source end records real-time shooting of the welding seam through two cameras at the head and tail of the robot, and then obtains the position of the robot relative to the welding seam after image processing, and then adjusts the vehicle speed in time according to the position deviation.

The continuous X-ray source 17 on the robot 1 at the ray source end is fixed in the center of the frame 14, with the radiation source facing downwards, and the digital flat panel on the robot 2 at the digital flat panel detector side is fixed at the bottom center of the frame 2 24. The digital flat panel is digital imaging The receiving side of the flat panel is facing downwards. When the robot 1 at the radiation source end and the robot 2 at the digital flat panel detector end are running, they are respectively located on the inside and outside of the spherical tank 4. The robot 1 at the radiation source end emits X-rays, and the robot 2 at the digital flat panel detector end The digital flat panel 27 is digitally imaged, so as to realize automatic non-destructive testing of weld seams.

The remote control of the ray source robot 1 is controlled by installing the wireless communication module 1 on the robot, and installing a wireless WiFi relay at the entrance and exit of the spherical tank 4, and then connecting the remote host computer 3 and the ray source robot 1 through WiFi , and the robot 1 at the ray source end and the robot 2 at the digital flat panel detector end transmit video information captured in real time through wireless WiFi. The upper computer 3 can remotely control the motion and working mode of the robot 1 at the ray source end and the robot 2 at the digital flat panel detector end.

The robot 1 at the ray source end and the robot 2 at the digital flat panel detector end are equipped with a level respectively, and the level instrument is respectively connected to the motion control box 1 and the motion control box 2, and the attitude of the ray source end robot 1 and the robot 2 at the digital flat panel detector end is calibrated through the level instrument , keep robot 1 at the ray source end and robot 2 at the digital flat panel detector end parallel.

The first frame 14 of the robot 1 at the ray source end and the second frame 15 of the robot 2 at the digital flat panel detector end are respectively provided with suspension vibration isolation devices 5 with the same structure. As shown in FIG. 4 , the radiation source robot 1 is taken as an example for illustration.

As shown in Figure 5, the suspension vibration isolation device 5 includes a flexible unit 51 and a horizontal mechanism. One end of the flexible unit 51 is located on the top platform of the magnet holder 57, and the other end of the flexible unit 51 is movably connected to the vehicle frame holder 56, and the magnet holder The bottom of 57 is connected with permanent magnet one 12, and vehicle frame fixing seat 56 connects the boss of bearing seat 53 by horizontal mechanism, and bearing seat 53 and magnet fixing seat 57 are connected servo motor one 16 by bolt respectively, and magnet fixing seat 57 is connected with servo motor. A motor fixing plate 52 is provided between the motor one 16, and the servo motor one 16 is connected to the Mecanum wheel one 13 by the axle 54.

The horizontal mechanism adopts more than one H-type connecting rod 55, as shown in Figure 8, more than one H-type connecting rod 55 is installed in parallel and is positioned on the same vertical plane, and the two ends of the H-type connecting rod 55 are respectively connected to the vehicle frame by pin shafts and fixed The boss of seat 56, the boss of bearing seat 53.

The flexible unit 51 is fixed between the top platform of the magnet holder 57 and the pressing plate 58 by bolts, as shown in Figure 6, the flexible unit 51 is composed of several leaf springs superimposed, and the leaf spring includes a long leaf spring located in the middle, and the length of the leaf spring is determined by the length of the leaf spring. The leaf spring decreases to both ends, and the long leaf spring gap fits in the empty groove of the holder, as shown in Figure 7, the long leaf spring can slide back and forth in the groove.

The flexible unit 51 is composed of one long leaf spring, two middle leaf springs, two short leaf springs and five leaf springs superimposed, and a middle leaf spring and a short leaf spring are symmetrically distributed on both sides of the long leaf spring.

The center of permanent magnet one 12 is positioned at wheel shaft 54 place vertical plane, and the walking surface of permanent magnet one 12 and Mecanum wheel one 13 is arranged in parallel.

As shown in Figure 4, when the Mecanum wheel vehicle of the ray source end robot 1 and the digital flat panel detector end robot 2 is assembled with the suspension vibration isolation device 5, the top surface of the frame fixing seat 56 is connected to the frame one 14 or the frame The two 24 are fixedly connected together, and the four suspension vibration isolation devices 5 are symmetrically installed according to the kinematic laws of Mecanum wheel 1 1313 and Mecanum wheel 2 23 .

When the Mecanum wheel vehicle crawled on the surface of the magnetic material, the resultant force of the permanent magnet magnet-12 and the Mecanum wheel vehicle's own weight provided positive pressure, and when a certain Mecanum wheel-13 ran into an obstacle, the Mecanum wheel-13 was lifted, permanently The magnetic magnet-12 and the Mecanum wheel-13 are lifted simultaneously, and the lower surface of the magnet is kept parallel to the adsorption surface. The other Mecanum wheels-13 are still close to the adsorption surface. After the permanent magnet-12 and the Mecanum wheel-13 have crossed the obstacle simultaneously, Re-adsorbed on the surface of magnetically permeable materials.

When the Mecanum wheel vehicle is crawling on the surface of the magnetic material, the gravitational force of the Mecanum wheel vehicle points to the adsorption surface, and the long leaf spring and the leaf spring between the long leaf spring and the top platform of the magnet holder 57 are deformed under force to provide a shock absorption effect ; When the gravitational force of the Mecanum wheel vehicle is facing away from the adsorption surface, the long leaf spring and the leaf spring between the long leaf spring and the pressing plate 58 are deformed under force to provide a shock absorption effect to realize the Mecanum wheel vehicle on the adsorption plane at any angle Shock absorption for crawling.

The suspension vibration isolation device 5 can meet the adsorption stability and motion stability of the Mecanum wheel, ensure the contact and pressure between the Mecanum wheel and the surface of the magnetic material, ensure the distance and parallelism of the permanent magnet adsorption surface, and make the adsorption effect more stable. , at the same time, the shock isolation unit can realize the shock isolation in the upper and lower directions, which can satisfy the shock isolation effect of the adsorption surface of the robot installed with the suspension system at various angles.

Two H-shaped connecting rods 55 and the boss of the vehicle frame holder 56 and the boss of the bearing seat 53 form a parallelogram linkage mechanism, which ensures that the Mecanum wheel and the permanent magnet 12 etc. are in translational motion, which can ensure that the permanent magnet 1 12 is parallel to the contact surface of the Mecanum wheel, thereby ensuring that the permanent magnet-12 has a stable adsorption force on the magnetically conductive adsorption surface.

The flexible unit 51 has five leaf springs distributed symmetrically. The folded springs have both good flexibility and strong load-bearing capacity. When the Mecanum wheel crosses obstacles, it can produce large deformation without causing damage due to excessive deformation. Failure, the symmetrically distributed overlapping springs can make the robot equipped with the suspension system have a shock absorption effect when crawling on a plane with any angle.

The permanent magnet-12 is installed on the position of the independent suspension, so that the suspension equipped with Mecanum wheels can still enter and stick to the adsorption surface even if it encounters obstacles during the crawling process, ensuring the movement characteristics of the robot equipped with Mecanum wheels. Moreover, the permanent magnet 12 is close to the Mecanum wheel, and the structural size of the suspension can ensure the distance between the magnet and the adsorption surface, and ensure the stable adsorption force of the magnet to the adsorption surface, and when encountering obstacles, the magnet can rise and fall with the Mecanum wheel at the same time to prevent accidents. The distance between the magnet and the adsorption surface is small and it collides with the obstacle.

Figure 9 is a working diagram of the entire control system. The robot 1 at the ray source end, the robot 2 at the digital flat panel detector end, and the host computer 3 communicate with each other and transmit information through WiFi. The robot 1 at the ray source end and the robot 2 at the digital flat panel detector end are respectively equipped with The wireless communication module, the front tracking sensor, the rear tracking sensor, the CAN communication module, the motion control box for controlling the motor, the servo motor and other modules realize the above functions.

The control system includes the robot 1 at the ray source end, the robot 2 at the digital flat panel detector end, and the upper computer 3, which is the operation center. The three units are connected through the wireless communication module 1 and the wireless communication module 2. The components of the control system of the robot 2 are roughly the same. The front tracking sensor 11 and the rear tracking sensor 15 of the robot 1 at the ray source end are digital cameras, which are used for automatic tracking by performing image processing on the captured pictures. The robot 1 communicates with the motor and the level meter through the CAN bus. The robot 1 at the ray source end calculates the speed of each motor according to the remote control or automatic tracking command, and sends the control command to each motor through the CAN bus. The encoder information of each motor and the level meter The information is transmitted back to the motion control box 18 of the ray source robot 1 through the CAN bus, and the motion control box 18 of the ray source robot 1 analyzes and calculates the returned information, and then transmits the information to the digital flat panel detection through the wireless communication module The robot 2 at the device end and the robot 2 at the digital flat panel detector end adjust the memory of their own motion commands according to the information transmitted by the robot 1 at the ray source end, and the finally calculated motion commands are transmitted to the motor through the CAN bus.

The Mecanum wheel weld detection robot of the embodiment adopts the Mecanum wheel omni-directional mobile platform and the AGV system, which fills the gap in digital ray automatic detection process equipment for large spherical tanks 4, vertical storage tanks and other in-service pressure-bearing special equipment at home and abroad. In addition to realizing advance and retreat, lateral movement, and turning in situ, the detection robot of the embodiment can also realize rotational movement around any point, especially in large-scale in-service pressure-bearing special equipment such as power plant boilers, spherical tanks, and vertical storage tanks. It can greatly improve the flexibility of the robot to detect the weld on the equipment surface.

This Mecanum wheel-based digital flat-panel radiographic inspection robot imaging system also includes a detection report generation module, which: through the processing of radiographic inspection images, performs qualitative identification of defects based on features, and performs quantitative and grading of defects, according to JB/T 4730.2-2005 and other relevant standards, combined with computer database technology, can automatically generate test reports, as shown in Figure 11.

The embodiment is applicable to the detection of various welds of large-scale pressure-bearing equipment such as spherical tanks and storage tanks, including longitudinal seams, circular seams, embedded joint welds, head joints, etc.; the robot's actions and degrees of freedom meet the requirements of weld detection Process requirements, robot movement accuracy meets the detection accuracy requirements; welding seam automatic tracking technology meets the field use requirements; the digital radiography technology and process adopted by the system meet the detection standard requirements. The embodiment finally forms a set of practical robot digital flat-panel ray detection system capable of automatically tracking welds, which can be used for automatic detection of welds of large-scale pressure-bearing special equipment with a diameter greater than 4m.

Claims (8)

1. a kind of omnidirectional mobile ray source end robot synchronous tracking method based on Mecanum wheel, it is characterized in that: The robot at the ray source end walks autonomously, and records the encoder information to obtain the number of rotations of each wheel, and then sends the information wirelessly to the robot at the digital flat panel detector end; The encoder information controls the rotation of each wheel of the robot at the digital flat panel detector end, and eliminates the cumulative error generated by the robot movement at the digital flat panel detector end; Eliminate the cumulative error caused by the robot movement at the digital flat panel detector end, specifically: from the pictures obtained by each digital flat panel exposure, the exposure area on the digital flat panel is obtained, and the exposure area is the position of the ray source, that is, the digital flat panel detector is obtained through the picture The positional offset distance of the end robot relative to the ray source end robot, and correct the motion of the digital flat panel detector end robot during the next walking process, to realize the synchronization between the digital flat panel detector end robot and the ray source end robot; Or, to eliminate the cumulative error caused by the movement of the robot at the digital flat panel detector end, specifically: the robot at the ray source end is equipped with a resistance wire, and the robot at the ray source end heats the tank body area facing the heat source through the resistance wire or infrared rays, and the heated area It will form the feature that the temperature is the highest at the point facing the heat source, and the temperature gradually decreases towards the surroundings; The robot on the digital flat-panel detector end has four symmetrical thermal sensors. The temperature difference between the four thermal sensors will generate a piezoelectric signal. If there is no alignment, the four thermal sensors will Different temperatures will cause a pressure difference in the generated piezoelectric signal. According to the pressure difference, the robot at the digital flat panel detector end is controlled to move toward the highest temperature point to realize the synchronization between the robot at the digital flat panel detector end and the robot at the ray source end. 2. The method for synchronously tracking the omnidirectional mobile ray source end robot based on the Mecanum wheel as claimed in claim 1, wherein the ray source end robot includes a frame one, a Mecanum wheel one, a servo motor one, and a front tracking sensor one , the rear tracking sensor one, the X-ray source, the permanent magnet one and the motion control box one, the motion control box one is arranged on the vehicle frame one, the front tracking sensor one is arranged on the front end of the vehicle frame one, and the rear tracking sensor one Set at the rear end of frame 1, the middle part of frame 1 is equipped with X-ray source, the two sides of frame 1 are respectively equipped with Mecanum wheel 1, Mecanum wheel 1 is connected with servo motor 1, and servo motor 1 is connected with motion control box 1 The two sides of the bottom of the frame one are respectively provided with a permanent magnet one. 3. the method for synchronously tracking the omnidirectional mobile ray source end robot based on the Mecanum wheel as claimed in claim 2, characterized in that: the digital flat panel detector end robot comprises a vehicle frame two, a Mecanum wheel two, a servo motor two, and a front tracking Sensor 2, rear tracking sensor 2, digital panel, permanent magnet 2 and motion control box 2, motion control box 2 is set on frame 2, front tracking sensor 2 is set at the front end of frame 2, rear tracking sensor The second is located at the rear end of the second frame, the middle part of the second frame is equipped with a digital panel, the digital panel is located at the bottom of the second frame, the two sides of the second frame are respectively equipped with two Mecanum wheels, and the second Mecanum wheel is connected to a servo motor Two, the servo motor two is connected to the motion control box two, and the two sides of the bottom of the frame two are respectively provided with permanent magnets two. 4. as claimed in claim 3, based on the omnidirectional moving ray source end robot synchronous tracking method of Mecanum wheel, it is characterized in that: the quantity of Mecanum wheel one and Mecanum wheel two is four, and Mecanum wheel one is provided with vehicle frame respectively Four ends of one, Mecanum wheel two are respectively arranged on four ends of vehicle frame two. 5. The method for synchronous tracking of omni-directional mobile ray source robot based on Mecanum wheel as claimed in claim 4, characterized in that: the ray source robot and the digital flat panel detector robot are respectively arranged on both sides of the detected object. 6. The Mecanum wheel-based method for synchronous tracking of omnidirectional moving ray source end robots according to claim 5, wherein a WiFi repeater is provided at the entrance and exit of the detected object. 7. The method for synchronous tracking of omnidirectional mobile ray source robot based on Mecanum wheel as claimed in claim 6, characterized in that: vehicle frame one and vehicle frame two are squares formed by vertically setting some longitudinal ribs and some transverse ribs structure. 8. as claimed in claim 7, based on the omnidirectional mobile ray source end robot synchronous tracking method of Mecanum wheel, it is characterized in that: between the permanent magnet one and the detected object, between the permanent magnet two and the detected object, respectively set gap.