A reconfigurable modular robot structure for aircraft surface quality inspection

Abstract

The application provides a reconfigurable modular robot structure for detecting the surface quality of an airplane, which comprises a computer and a plurality of robots, the robot comprising an omnidirectional wheel driving module and a detection module arranged on the back of the fuselage, and a power supply, a main control module, a propeller assembly and a docking module arranged on the front of the fuselage; the detection module is used for collecting the distance data from the back of the fuselage to the surface of the airplane in real time and transmitting the distance data to the computer through the main control module; the docking module comprises a female docking device and two male docking devices, and realizes the docking with any three robots; the main control module can upload the distance data, the position information and the motion parameters of the robot to the computer, and controls the rotation angle of the docking module, the rotating speed of the omnidirectional wheel driving module and the propeller assembly according to the action instruction sent by the computer; and the computer reconstructs the measured surface model of the airplane according to the distance data and the position information of the robot. The application is suitable for detecting the complex surface of the airplane and has high detection efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aircraft surface quality detection, and particularly relates to a reconfigurable modular robot structure for aircraft surface quality detection. BACKGROUND

[0002] The surface quality of an aircraft is crucial for achieving key aerodynamic performance indicators of the aircraft. In the process of manufacturing an advanced aircraft, the surface quality detection of the aircraft, as the last process of aircraft manufacturing, directly affects the delivery quality and use quality of the aircraft. In addition, after the aircraft is in service, the surface of the aircraft will be affected by factors such as impact, overload, fatigue and corrosion, and defects such as cracks, dents and corrosion spots will appear on the surface. Timely detection and repair measures can ensure safe flight.

[0003] The detection methods generally include manual detection and automatic detection. Manual detection is that an operator uses a contact type measuring instrument to inspect key topographic features of the surface of the aircraft. However, due to the quality, technical level and attention of the workers, the manual detection result usually has great subjectivity and uncertainty.

[0004] The equipment used in automatic detection mainly consists of a crawling robot or a mechanical arm equipped with a nondestructive testing device. The equipment generally has disadvantages such as complex structure, cumbersome operation, high energy consumption, large size, poor mobility and poor portability. A patent with publication number CN110654571A discloses a nondestructive detection robot system and method for surface defects of an aircraft skin. The detection system is composed of an AGV trolley, a six-degree-of-freedom mechanical arm, a multi-base station laser scanning full-space positioning system and the like, and realizes nondestructive detection of surface defects of the aircraft skin. However, the detection system needs to rely on a space base for positioning, and the movement space of the mechanical arm is limited, so the flexibility is poor and the detection system is not suitable for detection work in a large-scale range. A patent with publication number CN109244934A discloses a suspended aircraft assembly quality detection robot structure. The robot can move on a suspended rope, and detects the assembly quality through a cloud camera. However, the sliding on the rope and the shaking of the rope will affect the positioning accuracy and detection speed of the robot, and the arrangement of the rope is too high. SUMMARY

[0005] The application aims to solve the problems of high requirements, complex structure, poor flexibility and poor portability in different application scenarios of the prior art aircraft surface nondestructive detection device, and provides a reconfigurable modular robot structure for aircraft surface quality detection. The application includes several robots that can be freely combined and connected, and the robots are reconfigured through propellers and swing arms. The detection module attached to the body of the robot is used to detect the surface of the aircraft. The robot structure is suitable for various complex scenes, improves the efficiency of aircraft surface quality detection, and reduces the human resources required for aircraft surface quality detection.

[0006] To achieve the above objectives, the technical solutions provided by the present invention are:

[0007] A reconfigurable modular robot structure for aircraft surface quality inspection, which is special in that it includes a computer and several robots;

[0008] A single robot includes a body, power supply, main control module, propeller assembly, omnidirectional wheel drive assembly, docking module and detection module;

[0009] The omnidirectional wheel driving module and the detection module are located on the back of the fuselage;

[0010] The omnidirectional wheel drive module includes three omnidirectional wheel drive components, which are radially distributed on the back edge of the body and are used to drive the robot to move;

[0011] The detection module includes three laser ranging sensors for real-time acquisition of vertical distance data from the back of the fuselage to the surface of the aircraft being tested, and uploads the data to the main control module; the vertical distance data collected by multiple robots during movement form a point cloud set;

[0012] The propeller assembly is installed at the center of the fuselage and is used to generate upward or downward thrust;

[0013] The power supply, main control module and docking module are arranged on the front of the fuselage;

[0014] The power supply is used to supply power to the main control module, propeller assembly, omni-directional wheel drive assembly and docking module;

[0015] The docking module includes a female docking device, a first male docking device, and a second male docking device, which are arranged at a 120-degree angle around the circumference of the fuselage on the front edge of the fuselage and are staggered with the three omnidirectional wheel drive assemblies. The female docking device can be plugged and matched with the first male docking device or the second male docking device of any robot, and the first male docking device and the second male docking device can be plugged and matched with the female docking device of any robot to achieve docking and reconfiguration between robots.

[0016] The first male docking device on the robot is used to drive the robot docked therewith to generate pitch motion during the reconstruction process, and the second male docking device on the robot is used to drive the robot docked therewith to generate roll motion during the reconstruction process;

[0017] The main control module includes an integrated main controller, a 5V step-down circuit and an IMU six-axis sensor;

[0018] The 5V step-down circuit is used to process the power supply according to the control signal of the main controller and output a 5V voltage signal to the female docking device, the first male docking device, the second male docking device and the omnidirectional wheel drive assembly;

[0019] The IMU six-axis sensor is used to measure the robot angular acceleration and acceleration in real time and is transmitted to the main controller of the robot;

[0020] The main controller is wirelessly connected with the computer, can upload the distance data collected by the detection module and the robot position information and motion parameters collected by the IMU six-axis sensor to the computer, and can control the rotation angle of the first male head docking device and the second male head docking device, the rotation speed of the omni-directional wheel driving module and the propeller assembly according to the action instructions sent by the computer;

[0021] The detection module includes three laser ranging sensors for collecting the vertical distance data from the back of the fuselage to the measured aircraft surface in real time and uploading to the main control module; a plurality of robots collect vertical distance data during movement, and the corresponding robot fuselage attitude and position are used as references to register to form a point cloud set;

[0022] The computer is used to send action instructions to the main controller according to the received robot position information and motion parameters, and can perform data reconstruction to form an aircraft measured surface model according to the point cloud set formed by a plurality of robots during movement and the position information of the robots.

[0023] Further, the female head docking device includes a female head, a movable pin, an electromagnet bracket, an electromagnet and an electromagnetic relay; the female head includes a rectangular piece provided with a notch and a U-shaped piece, the openings of the rectangular piece and the U-shaped piece are radially outward along the fuselage, and can be plugged and matched with the first male head docking device or the second male head docking device of other robots;

[0024] The movable pin, the electromagnet bracket, the electromagnet and the electromagnetic relay are arranged at one side of the opening of the U-shaped piece, and the rectangular piece is located at one side of the closed end of the U-shaped piece;

[0025] The electromagnet is fixedly installed on the surface of the fuselage through the electromagnet bracket, the electromagnet is a hollow structure, the movable pin can pass through the electromagnet and be axially fixed in the mounting hole of the electromagnet through the spring, can reciprocate along the mounting hole of the electromagnet and not fall out;

[0026] The electromagnetic relay can act under the activation of the high and low level of the serial port sent by the main control module, control the power-on or power-off of the electromagnet; the magnetic force generated by the electromagnet is in the axial direction of the movable pin; when the electromagnet is powered off, the movable pin is fixedly inserted into the cavity of the U-shaped piece under the spring force and does not move, when the electromagnet is powered on, the movable pin moves reversely and retracts under the magnetic force greater than the spring force.

[0027] Further, the first male docking device comprises a first steering engine and a first swing arm, the first steering engine is fixed on the edge of the front surface of the machine body, the output shaft of the first steering engine faces the outside of the machine body, and the axis of the output shaft of the first steering engine is along the radial direction of the machine body;

[0028] The first swing arm is a U-shaped structure, the center of the bottom of the first swing arm is connected with the output shaft of the first steering engine, the first swing arm rotates around the axis of the output shaft under the drive of the first steering engine, and the rotation plane of the first swing arm is perpendicular to the plane where the front surface of the machine body is located;

[0029] The two open ends of the first swing arm can be inserted and matched with the U-shaped piece and the rectangular piece of the female head of another robot female docking device;

[0030] A first positioning hole is arranged on one side wall of the first swing arm, the axis of the first positioning hole is perpendicular to the axis of the output shaft of the first steering engine, and the first positioning hole is used to lock the first male docking device and the female docking device of another robot after the first male docking device is docked with the female docking device of another robot through the cooperation of the movable pin of the female docking device.

[0031] Further, the second male docking device comprises a second steering engine and a second swing arm, and the second steering engine is fixed on the edge of the front surface of the machine body;

[0032] The second swing arm comprises a U-shaped structure, one side wall of the U-shaped structure is symmetrically arranged relative to the bottom wall of the U-shaped structure, one end of the side wall of the U-shaped structure is connected with the output shaft of the second steering engine, the axis of the output shaft of the second steering engine is parallel to the bottom wall of the U-shaped structure of the second swing arm, the second swing arm swings around the axis of the output shaft under the drive of the second steering engine, and the rotation plane of the second swing arm is perpendicular to the plane where the front surface of the machine body is located;

[0033] The two open ends of the second swing arm can be inserted and matched with the U-shaped piece and the rectangular piece of the female head of another robot female docking device;

[0034] A second positioning hole is arranged on the other side wall of the U-shaped structure of the second swing arm, the axis of the second positioning hole is parallel to the axis of the output shaft of the second steering engine, and the second positioning hole is used to lock the second male docking device and the female docking device of another robot after the second male docking device is docked with the female docking device of another robot through the cooperation of the movable pin of the female docking device.

[0035] Further, the omni-directional wheel driving assembly comprises a stepping motor, a stepping motor driving board and an omni-directional wheel;

[0036] The omni-directional wheel comprises an omni-directional wheel framework and omni-directional wheel rollers, a plurality of omni-directional wheel rollers are uniformly distributed on the rim of the omni-directional wheel framework in the circumferential direction of the omni-directional wheel framework, and the axis of the omni-directional wheel roller is perpendicular to the axis of the omni-directional wheel framework;

[0037] The omni-directional wheel framework is coaxially connected with the stepping motor, and the omni-directional wheel framework is arranged towards the center of the fuselage, and the stepping motor is arranged away from the center of the fuselage.

[0038] The stepping motor driving board is fixed on the back of the fuselage and close to the stepping motor, and is used for controlling the rotation speed and forward and reverse rotation of the stepping motor according to the control signal sent by the master control module.

[0039] Further, the propeller assembly comprises a propeller and a propeller support;

[0040] The propeller support is arranged on the back of the fuselage and located in the middle of the fuselage;

[0041] The propeller comprises a propeller controller, a propeller electronic governor, a propeller motor and a propeller blade;

[0042] The propeller electronic governor and the propeller motor are installed in the middle of the propeller blade;

[0043] The propeller blade is fixed on the propeller support, and the center of the propeller coincides with the center of the fuselage;

[0044] The propeller controller is integrated with the master controller, and is used for converting the serial port signal output by the master controller into a PWM signal and transmitting the PWM signal to the propeller electronic governor, so as to realize accurate control of the rotation speed of the propeller motor.

[0045] Further, the female head docking device, the first male head docking device and the second male head docking device are arranged at 60 degrees staggered with the three omni-directional wheel driving assemblies.

[0046] Further, the power supply adopts a lithium ion polymer battery.

[0047] Further, the computer and the master controller of the robot both run the ROS2 system, and the master control systems of the computer and the robot are connected through WIF and communicate with each other in the same local area network.

[0048] The computer can register the point cloud set formed by the plurality of robots in the motion process with the position information of the robot through the least square method, and reconstruct the measured surface model of the airplane through the Poisson method after registration.

[0049] Further, the fuselage is a six-sided column, and the connecting part between adjacent surfaces is designed as a round corner.

[0050] The advantages of the present application are:

[0051] 1. The reconfigurable modular robot structure of the present application comprises a plurality of single robots, each of which is provided with a docking device and can be connected to any three robots, and after docking and reconfiguration, can cross the surface obstacles of an airplane to detect the complex surface of the airplane, has strong environmental adaptability, improves the detection efficiency of the surface of the airplane, and reduces the human resources required for the quality detection of the surface of the airplane.

[0052] 2. In the present application, the overall size of the single robot is small, only 15cm*15cm*2.5cm, and it can pass through a narrower area for detection; the single robot is light in weight, only 200g, and avoids secondary damage to the surface of the airplane caused by excessive weight.

[0053] 3. In the present application, the bottom of the robot is provided with an omnidirectional wheel and a laser ranging sensor, the omnidirectional wheel slides on the surface of the airplane, the laser ranging sensor collects the vertical distance of the surface of the airplane, realizes the close-range detection of the defects on the surface of the airplane, and improves the detection accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0054] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

[0055] Figure 1 is a front view of the modular robot structure of the present application;

[0056] Figure 2 is a back view of the modular robot structure of the present application;

[0057] Figure 3 is a schematic view of the omnidirectional wheel driving module structure in the present application;

[0058] Figure 4 is a schematic view of the female head assembly structure in the present application;

[0059] Figure 5 is a schematic view of the structure of the first docking module male head assembly in the present application;

[0060] Figure 6 is a schematic view of the structure of the second docking module male head assembly in the present application

[0061] Figure 7 is a schematic view of the mutual docking and reconfiguration of a plurality of robots in the present application;

[0062] Figure 8 is a schematic view of the overall electrical control structure in the present application;

[0063] Figure 9 is a schematic view of the process of crossing an L-shaped obstacle after reconfiguration of the four robots in the embodiment of the present application.

[0064] Explanation of reference signs: 1 - body, 2 - power supply, 3 - main control module, 4 - propeller, 5 - propeller support, 6 - omni-directional wheel, 601 - omni-directional wheel framework, 602 - omni-directional wheel roller, 7 - stepping motor, 8 - stepping motor drive board, 9 - laser ranging sensor, 10 - female head docking device, 1001 - female head, 1002 - electromagnetic relay, 1003 - electromagnet support, 1004 - electromagnet, 1005 - movable pin, 11 - first male head docking device, 1101 - first steering engine, 1102 - first swing arm, 1103 - first positioning hole, 12 - second male head docking device, 1201 - second steering engine, 1202 - second swing arm, 1203 - second positioning hole. DETAILED DESCRIPTION

[0065] The embodiments of the present application are described in detail below, which are exemplary and intended to explain the present application, and cannot be understood as a limitation of the present application.

[0066] Reference Figure 1 and Figure 2 A reconfigurable modular robot structure for aircraft surface quality detection includes a computer and a plurality of robots, and each robot includes a body 1, a power supply 2, a main control module 3, a propeller assembly, an omni-directional wheel driving module, a docking module, and a detection module. The main control module of each robot is connected with the computer through WIFI, the omni-directional wheel driving module includes three omni-directional wheels, which are arranged at an interval of 120 degrees around the edge of the bottom surface of the body and are used to realize the movement of the robot. The propeller assembly includes a propeller 4 and a propeller support 5, and the propeller 4 is fixed at the center of the body through the propeller support 5. The docking module is used for mutual docking and reconfiguration between the plurality of robots, and acts as a joint during the reconfiguration of the chained robot after docking, and includes a female head docking device, a first male head docking device 11, and a second male head docking device 12, which are arranged at an interval of 120 degrees around the edge of the top surface of the body and are arranged at an interval of 60 degrees with the three omni-directional wheels. The detection module includes three laser ranging sensors installed on the bottom surface of the body, which are used to collect the vertical distance information from the laser ranging sensor itself to the surface of the measured aircraft and transmit it to the main control module; and the main control module 3 is used to control the rotation angle of the docking module, the rotation speed of the omni-directional wheel, and the rotation speed of the propeller.

[0067] The body 1 has a hexagonal column structure, a central hole is opened in the middle along the axis, and a plurality of mounting holes are arranged on the body, which are used to fix the main control module, the omni-directional wheel driving module, the docking module, and the detection module.

[0068] The propeller 4 is fixed on the body through the propeller support 5, and the center of the propeller coincides with the center of the body, which is used to compensate for gravity, reduce the bearing force at the joint, and provide power when the omni-directional wheel cannot provide power during the reconfiguration of the multi-module.

[0069] Referring to Figure 3 , the single omni-wheel 6 includes an omni-wheel framework 601 and omni-wheel rollers 602, the plurality of omni-wheel rollers 602 are evenly distributed on the edge of the omni-wheel framework 14 in the circumferential direction of the omni-wheel framework, and the stepping motor 13 coaxially connected with the omni-wheel framework 14 drives the omni-wheel rollers 602 to rotate. The omni-wheel framework 14 is arranged towards the center of the fuselage, and the stepping motor 13 is arranged away from the center of the fuselage, so that the track of the omni-wheel is minimized to realize stable movement on the surface of the aircraft with smaller curvature and detection of the surface of the aircraft. The three omni-wheels arranged radially on the edge of the bottom surface of the fuselage are arranged at an angle of 120 degrees from each other, and the speed and forward and reverse rotation of the stepping motor are controlled by the main control module 3 to realize motion synthesis, so as to realize the omni-directional movement of the omni-wheel in the plane.

[0070] Referring to Figure 4 , the female head docking device 10 includes a female head 1001, a movable pin 1005, an electromagnet support 1003, an electromagnet 1004 and an electromagnetic relay 1002. The female head 1001 includes a U-shaped piece and a rectangular piece, and the rectangular piece is a cavity structure with open ends. The U-shaped piece is arranged at a distance from the rectangular piece, with the closed end of the U-shaped piece facing the rectangular piece and the open end facing the electromagnet 1004 where the movable pin 1005 is installed.

[0071] The electromagnet support 1003 is fixed on the surface of the fuselage, and the electromagnet 1004 is arranged on the top of the electromagnet support 1003; the electromagnet 1004 is a rectangular frame structure, and the movable pin 1005 passes through the electromagnet 1004 and can be extended or retracted along the mounting hole of the electromagnet. The female head of one robot can cooperate with any male head of another robot. Before cooperation, the robot main control module sends a high or low level of serial port to activate the electromagnetic relay 1002, and the electromagnetic relay operates to control the opening of the power-on switch on the electromagnet 1004. The power supply 2 supplies power to the electromagnet through the 5V voltage reduction unit on the main control module, and the electromagnet is powered on, so that the movable pin located thereon is retracted from the U-shaped piece. After the swing arm of the male head of another robot is inserted into the U-shaped piece and the rectangular piece of the female head, the main control module controls the electromagnet to be powered off, the movable pin is extended, and is clamped into the positioning hole on the swing arm of the male head of another robot, so as to realize the docking and reconstruction of the two robots.

[0072] Referring to Figure 5 , the first male head docking device 11 includes a first steering gear 1101 and a first swing arm 1102. The first steering gear 1101 is fixed on the edge of the top surface of the fuselage, and the first swing arm 1102 is a U-shaped structure. The output shaft of the first steering gear is connected with the center of the bottom of the U-shaped structure and is locked by a bolt. The open end of the first swing arm 1102 faces the outside of the fuselage, and the axis of the output shaft of the first steering gear is perpendicular to the axis of the fuselage; the first swing arm can rotate around the output shaft of the first steering gear under the drive of the first steering gear, and the rotation plane of the first swing arm is perpendicular to the horizontal plane where the fuselage is located.

[0073] The first swing arm 1102 has a first positioning hole 1103 on one side wall, and the axis of the first positioning hole is perpendicular to the axis of the output shaft of the first steering engine. When the first male docking device 11 is docked with the female docking device of another robot, the two ends of the open end of the first swing arm are inserted into the notches of the U-shaped piece and the rectangular piece of the female docking device, the electromagnetic relay of the female docking device of another robot is turned on, the movable pin is inserted into the positioning hole of the first swing arm 1102, the first swing arm is locked with the female docking module of another robot, the docking of the two robots is realized, and the two robots after docking can roll 360 degrees around the axis of the output shaft of the first steering engine.

[0074] Referring to Figure 6 , the second male docking device 12 includes a second steering engine 1201 and a second swing arm 1202. The second steering engine 1201 is fixed on the edge of the top surface of the body, and the second swing arm 1202 includes a U-shaped structure, and one side wall of the U-shaped structure is symmetrically arranged relative to the bottom wall. The side wall is connected with the output shaft of the second steering engine away from the open end of the U-shaped structure, and the axis of the output shaft of the second steering engine is parallel to the bottom wall of the U-shaped structure of the second swing arm. The second swing arm 1202 can rotate around the output shaft of the second steering engine, and the rotation plane of the second swing arm is perpendicular to the horizontal plane of the body.

[0075] The other side wall of the U-shaped structure of the second swing arm is provided with a second positioning hole 1203, and the axis of the second positioning hole is parallel to the axis of the output shaft of the second steering engine. When the second male docking device 12 is docked with the female docking device of another robot, the two ends of the open end of the U-shaped structure of the second swing arm are inserted into the notches of the U-shaped piece and the rectangular piece of the female docking device, the electromagnetic relay of the female docking device of another robot is turned on, the movable pin is inserted into the positioning hole of the second swing arm 1202, the second swing arm is locked with the female docking module of another robot, the docking of the two robots is realized, and the two robots after docking can roll 360 degrees around the axis of the output shaft of the second steering engine.

[0076] Referring to Figure 7 Each robot includes a female docking device 10, a first male docking device 11 and a second male docking device 12, which can be docked with three robots respectively. Figure 7 The first docking module male and the second docking module male of one robot are shown in the docking relationship with the female docking devices of the other two robots. In actual application, the number of robots and the docking reconfiguration can be freely set according to the information such as the size of the obstacles to be crossed on the surface of the aircraft and the size of the narrow space when performing detection tasks.

[0077] Referring to Figure 8, the power supply 2 and the main control module 3 are fixed on the top surface of the fuselage, and the main control module 1 comprises an integrated main controller, a propeller controller, a 5V voltage reduction circuit and an IMU six-axis sensor. The main controller adopts Raspberry Pi Zero2W, and is integrated with wireless communication function and computer communication. The computer and the main controller run ROS2 system, which is used for controlling the rudder angle of the first male head docking device 11 and the second male head docking device 12, the step motor speed of the omni-directional wheel driving module and the propeller speed through the output PWM signal, controlling the on-off of the electromagnetic relay of the female head docking device through the high and low level output by the serial port, receiving the distance information uploaded by the detection module through the USB serial port communication, and communicating with other robots and computers through WIFI protocol. The propeller controller adopts an STM32 chip, which is used for converting the serial port signal output by the main controller into a PWM signal and transmitting it to the propeller electronic governor, so as to realize accurate control of the propeller motor speed. The power supply 2 adopts a lithium ion polymer battery, and the main controller controls the lithium ion polymer battery to output a 5V voltage signal to the electromagnetic relay in the female head docking device, the rudder in the first male head docking module and the second male head docking module, and the step motor driving board in the omni-directional wheel driving assembly through the 5V voltage reduction circuit. The IMU six-axis sensor is used for measuring the angular acceleration and acceleration of the robot in real time and transmitting them to the main controller of the robot. The main controller calculates the position information of the robot itself during the movement according to the angular acceleration and acceleration of the robot. The electric control structure of a single robot can be divided into a communication layer, a control layer and a power layer. In the communication layer: the three laser ranging sensors in the detection module transmit the detected vertical distance data of the aircraft surface to the main controller, and the main controller fuses and calculates the data collected by the three laser ranging sensors to obtain the vertical distance information of the current detection surface and the bottom surface of the fuselage. The IMU six-axis sensor integrated in the main control module transmits the collected position information of the robot itself and the motion information of the fuselage to the main controller for solving, so as to obtain the position, attitude and speed information of the robot. Among them, the computer and the main controller of the robot run the ROS2 system, and communicate through WIFI signals. On the computer, the point clouds collected by multiple robots are registered by the mutual position of the robots through the least square method, and then the aircraft surface to be detected is reconstructed by the Poisson method. In the control layer: the main controller is directly connected with the propeller controller through the serial port, the serial port signal output by the main controller is converted into a PWM signal by the propeller controller and transmitted to the propeller electronic governor, and the propeller motor is controlled by the propeller electronic governor, so that the propeller blades rotate to generate thrust. In the power layer: the lithium ion polymer battery outputs a 5V voltage signal through the BEC circuit in the propeller electronic governor, which directly supplies power to the main controller and the propeller controller, and supplies power to the electromagnetic relay of the female head docking device, the rudder of the first male head docking device and the second male head docking device, and the step motor driving board of the omni-directional wheel driving module through the 5V voltage reduction circuit integrated on the main control module.

[0078] Referring to Figure 9 , the process of the chain robot structure composed of four sequentially butt-jointed connecting robots crossing an L-shaped obstacle is shown.

[0079] Referring to Figure 9 a, the master module of the first robot sends an advancing signal, and the omnidirectional wheels do not move due to the existence of the obstacle. The IMU six-axis sensor integrated in the master module collects the position and speed information of the robot to the master module. The master module determines that an obstacle is encountered and transmits this information to the PC through WIFI. The PC sends the crossing obstacle instruction to the master modules of the four robots through WIFI. First, the master module of the first robot sends a PWM signal to the steering engine of the second robot connected thereto, so that the steering engine rotates and the first robot is lifted. The omnidirectional drive modules of the first, second and third robots receive the PWM signal sent by the master module of the robot and move forward to approach the obstacle, so that the first robot gradually contacts the obstacle, as shown in Figure 9 b;

[0080] When the laser ranging sensor 9 of the first robot detects that the distance from the obstacle is less than a certain threshold, the detected data is transmitted to the PC through the master module of the robot. The PC continues to issue instructions to the four robots. The steering engine and the swing arm of the first robot are reversed compared to before. The master module of the second robot sends a PWM signal to the steering engine of the third robot connected thereto. The steering engine of the third robot rotates, so that the second robot is lifted. The first robot moves to approach the upper surface of the obstacle. The first robot sends a PWM signal to the propeller thereof, so that the propeller rotates to generate an upward thrust. The third and fourth robots continue to move forward to approach the obstacle, until the laser ranging sensor of the first robot detects that the first robot crosses the obstacle, as shown in Figure 9 c;

[0081] The PC sends instructions to the master modules of the third and fourth robots. The third and fourth robots continue to move forward to approach the obstacle, until the laser ranging sensor of the second robot detects that the second robot crosses the obstacle and transmits this information to the master module of the second robot and the PC. The propeller of the second robot starts to rotate to generate a downward thrust, as shown in Figure 9 d; then the PC sends instructions. The third and fourth robots move forward. The master module of the third robot sends a PWM signal to the steering engine thereof. The steering engine rotates to lift the third robot and continue to approach the obstacle, as shown in Figure 9 e;

[0082] After the third robot's laser ranging sensor detects that the distance between it and the obstacle is less than a certain threshold, it transmits the measurement result to the PC. The PC then sends instructions to the four robots. The servos and swing arms of the second and third robots are reversed compared to before, making the robots take on an arch shape. At this time, all the omnidirectional wheels are off the ground. The main control modules of the third and fourth robots send PWM signals to their own propellers. At this time, the propellers of the four modules all start to rotate, and the thrust generated makes the robots move forward and gradually cross the obstacle. Figure 9 f shown;

[0083] When the laser ranging sensor of the fourth robot detects that the distance to the obstacle is less than a certain threshold, it transmits a signal to the PC. The PC continues to issue instructions to the main control modules of the four robots. The servo of the first robot reverses compared to before, making the first robot gradually parallel to the ground. When the laser ranging sensor of the first robot detects that the distance to the ground is less than a certain threshold, it transmits the signal to the PC. The PC sends an instruction to stop all propellers, such as Figure 9 As shown in g;

[0084] The first robot transmits PWM signals to its own omnidirectional wheel drive module, and the omnidirectional wheel moves forward, driving the first robot away from obstacles. The second and third servos receive PWM signals from their own main control modules and reverse their previous rotations, making them gradually parallel to the ground. Figure 9 As shown in h;

[0085] When the laser ranging sensors of all four robots detect that the distance to the ground is less than a certain threshold, a signal is transmitted to the PC. The PC determines that the obstacle has been successfully crossed, ends the instruction sending, and waits for the operator to take the next step of control.

[0086] The more robots that are reconfigured, the longer the robot chain structure will be. Figure 9 The larger the arch structure formed in f, the easier it is to cross larger obstacles, so the number of robots to be docked and reconstructed can be freely selected according to the size of the obstacle, and a balance can be struck between crossing ability and control difficulty.

[0087] The reconfigurable modular robot described in the present invention can realize chain connection of multiple robots. Through the combination of their respective omnidirectional wheel drive modules, the reconfiguration movement of the docking device and the thrust of the propeller, it can achieve functions such as movement on the curved surface of the aircraft, crossing the frames, ribs and other structures on the aircraft wall panels, and reaching areas with confined spaces, thereby inspecting the aircraft surface structure.

[0088] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, and these modifications or replacements shall be covered within the protection scope of the present application.

Claims

1. A reconfigurable modular robot structure for aircraft surface quality inspection, characterized in that: including computers and several robots; A single robot includes a body, power supply, main control module, propeller assembly, omnidirectional wheel drive assembly, docking module and detection module; The omnidirectional wheel driving module and the detection module are located on the back of the fuselage; The omnidirectional wheel drive module includes three omnidirectional wheel drive components, which are radially distributed on the back edge of the body and are used to drive the robot to move; The detection module includes three laser ranging sensors for real-time acquisition of vertical distance data from the back of the fuselage to the surface of the aircraft being tested, and uploads the data to the main control module; the vertical distance data collected by multiple robots during movement form a point cloud set; The propeller assembly is installed at the center of the fuselage and is used to generate upward or downward thrust; The power supply, main control module and docking module are arranged on the front of the fuselage; The power supply is used to supply power to the main control module, propeller assembly, omni-directional wheel drive assembly and docking module; The docking module includes a female docking device, a first male docking device, and a second male docking device, which are arranged at a 120-degree angle around the front edge of the fuselage and staggered with the three omnidirectional wheel drive assemblies. The female docking device can be plugged into or mate with the first male docking device or the second male docking device of any robot to achieve docking and reconfiguration between the robots. The first male docking device on the robot is used to drive the robot docked therewith to generate pitch motion during the reconstruction process, and the second male docking device on the robot is used to drive the robot docked therewith to generate roll motion during the reconstruction process; The main control module includes an integrated main controller, a 5V step-down circuit and an IMU six-axis sensor; The 5V step-down circuit is used to process the power supply according to the control signal of the main controller and output a 5V voltage signal to the female docking device, the first male docking device, the second male docking device and the omnidirectional wheel drive assembly; The IMU six-axis sensor is used to measure the robot's angular acceleration and acceleration in real time and transmit them to the robot's main controller; The main controller is wirelessly connected to the computer and can upload the distance data collected by the detection module and the robot position information and motion parameters collected by the IMU six-axis sensor to the computer, and can control the rotation angle of the first male docking device and the second male docking device, the rotation speed of the omnidirectional wheel drive module and the propeller assembly according to the action instructions sent by the computer; The detection module includes three laser ranging sensors for collecting vertical distance data from the back of the fuselage to the surface of the aircraft being tested in real time and uploading it to the main control module; The vertical distance data collected by multiple robots during movement are registered with the corresponding robot body posture and position as a reference to form a point cloud set; The computer is used to send action instructions to the main controller based on the received robot position information and motion parameters, and can reconstruct data to form a model of the aircraft's measured surface based on the point cloud set collected by multiple robots during movement and the robots' position information.

2. The reconfigurable modular robot structure according to claim 1, characterized in that: The female docking device includes a female head, a movable pin, an electromagnet bracket, an electromagnet, and an electromagnetic relay; the female head includes a rectangular member with a notch and a U-shaped member, the openings of the rectangular member and the U-shaped member facing radially outward along the body, and can be plugged and matched with the first male docking device or the second male docking device of another robot; The movable pin, electromagnet bracket, electromagnet and electromagnetic relay are arranged on the opening side of the U-shaped part, and the rectangular part is located on the closed end side of the U-shaped part; The electromagnet is fixedly mounted on the surface of the fuselage through an electromagnet bracket. The electromagnet has a cavity structure. The movable pin passes through the electromagnet and is axially fixed in the mounting hole of the electromagnet by a spring. The movable pin can reciprocate along the mounting hole of the electromagnet without falling out. The electromagnetic relay can be activated by the high and low levels of the serial port sent by the main control module to control the power on or off of the electromagnet; the direction of the magnetic force generated by the electromagnet is along the axial direction of the movable pin; when the electromagnet is de-energized, the movable pin can be extended into the U-shaped cavity and fixed under the action of the spring force; when the electromagnet is energized, the movable pin moves in the opposite direction and retracts under the action of the magnetic force greater than the spring force.

3. The reconfigurable modular robot structure according to claim 2, characterized in that: The first male docking device includes a first servo and a first swing arm, the first servo is fixed to the front edge of the fuselage, the output shaft of the first servo faces outward from the fuselage, and the axis of the output shaft of the first servo is along the radial direction of the fuselage; The first swing arm is a U-shaped structure, the bottom center of the first swing arm is connected to the output shaft of the first steering gear, and the first swing arm rotates around the axis of the output shaft under the drive of the first steering gear, and the rotation plane of the first swing arm is perpendicular to the plane of the front of the fuselage; The two open ends of the first swing arm can be plugged into and matched with the U-shaped piece and the rectangular piece of the female head in another robot female head docking device; A first positioning hole is provided on one side wall of the first swing arm, and the axis of the first positioning hole is perpendicular to the axis of the output shaft of the first servo; the first positioning hole is used to lock the first male docking device with the female docking device of another robot by cooperating with the movable pin of the female docking device after the first male docking device is docked with the female docking device of another robot.

4. The reconfigurable modular robot structure according to claim 3, characterized in that: The second male docking device comprises a second servo and a second swing arm; the second servo is fixed to the front edge of the fuselage; The second swing arm comprises a U-shaped structure, wherein a side wall of the U-shaped structure is symmetrically arranged relative to a bottom wall thereof, and an end of the side wall remote from the opening of the U-shaped structure is connected to an output shaft of a second servo, wherein the axis of the output shaft of the second servo is parallel to the bottom wall of the U-shaped structure of the second swing arm; the second swing arm swings about the axis of the output shaft when driven by the second servo, and the rotation plane of the second swing arm is perpendicular to the plane of the front of the fuselage; The two open ends of the second swing arm can be plugged into and matched with the U-shaped piece and the rectangular piece of the female head in another robot female head docking device; A second positioning hole is provided on the other side wall of the U-shaped structure in the second swing arm, and the axis of the second positioning hole is parallel to the axis of the output shaft of the second servo; the second positioning hole is used to lock the second male docking device with the female docking device of another robot by cooperating with the movable pin of the female docking device after the second male docking device is docked with the female docking device of another robot.

5. The reconfigurable modular robot structure according to claim 4, characterized in that: The omnidirectional wheel drive assembly includes a stepper motor, a stepper motor drive board and an omnidirectional wheel; The omnidirectional wheel comprises an omnidirectional wheel frame and omnidirectional wheel rollers, wherein a plurality of omnidirectional wheel rollers are evenly distributed on the rim of the omnidirectional wheel frame in the circumferential direction of the omnidirectional wheel frame, and the axes of the omnidirectional wheel rollers are perpendicular to the axis of the omnidirectional wheel frame; The omnidirectional wheel frame is coaxially connected to the stepper motor, and the omnidirectional wheel frame is arranged toward the center of the fuselage, and the stepper motor is arranged away from the center of the fuselage; The stepper motor drive board is fixed on the back of the fuselage and close to the stepper motor, and is used to control and adjust the speed and forward and reverse rotation of the stepper motor according to the control signal sent by the main control module.

6. The reconfigurable modular robot structure according to claim 5, characterized in that: The propeller assembly includes a propeller and a propeller bracket; The propeller bracket is arranged on the back of the fuselage and located in the middle of the fuselage; The propeller includes a propeller controller, a propeller electronic controller, a propeller motor and blades; The propeller electric regulator and the propeller motor are installed in the middle of the blade; The blades are fixed to the propeller bracket, and the center of the propeller coincides with the center of the fuselage; The propeller controller is integrated with the main controller and is used to convert the serial port signal output by the main controller into a PWM signal and transmit it to the propeller ESC to achieve precise control of the propeller motor speed.

7. The reconfigurable modular robot structure according to claim 6, characterized in that: The female docking device, the first male docking device and the second male docking device are respectively arranged to be staggered at 60 degrees with the three omni-directional wheel drive assemblies.

8. The reconfigurable modular robot structure according to claim 7, characterized in that: The power source adopts a lithium-ion polymer battery.

9. The reconfigurable modular robot structure according to claim 1, characterized in that: The computer and the robot's main controller both run the ROS2 system, and the computer and the robot's main control system are connected via Wi-Fi and communicate with each other within the same local area network; The computer can register the point cloud set collected by multiple robots during movement with the position information of the robots through the least square method, and reconstruct the measured surface model of the aircraft through the Poisson method after the registration.

10. The reconfigurable modular robot structure according to any one of claims 1 to 9, characterized in that: The fuselage is a hexagonal column, and the joints between adjacent faces are rounded.

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