Modular self-reconfigurable robot connection and reconfiguration method

Abstract

The application provides a modular self-reconfigurable robot connection and reconstruction method, which comprises the following steps: setting a DPM code on the robot, identifying the DPM code on the male joint device of another robot based on the camera device on the position of the female joint device of the robot, jointly controlling the robot movement by the PC host and the master module on the robot, fusing the DPM code image recognition decoding result and the IMU six-axis sensor measurement result to obtain the real-time relative position of the two robots, and controlling the female joint device of the robot to be connected with the male joint device of another robot to complete the robot connection. The master module controls the rotation or pitch of the male joint device to realize the position reconstruction of the two robots after the connection. In the reconstruction process, the propeller speed is taken as the control object, the propeller thrust is adjusted based on the PID control to compensate the torque at the joint of the robot due to gravity, the flexibility of the robot is enhanced, and the joint bearing force is reduced. The method provided by the application is accurate and reliable in connection and reconstruction.

Description

Technical Field

[0001] The present invention belongs to the technical field of robot automatic reconfiguration, and in particular relates to a modular self-reconfigurable robot connection and reconfiguration method. Background Art

[0002] Modular self-reconfigurable robots are generally composed of multiple different or identical modules connected to each other. By changing the connection and relative position relationship of each module to update its overall configuration, it can enhance its adaptability in unstructured environments and improve its ability to perform special tasks such as rescue and search.

[0003] Currently, the main connection devices for self-reconfigurable modular robots include mechanical, electromagnetic, and adhesive types. Mechanical connections are stable and avoid continuous energy consumption. However, the commonly used mechanical connection devices are used to act as motion joints between multiple modules after docking. Therefore, they are integrated with gear sets and other large transmission mechanisms. They are generally large in size and weight, which is not conducive to lightweight robots. It is also difficult for robots to carry more functional equipment to complete additional tasks. After the robot is connected, the configuration change mainly relies on the joint movement to generate thrust or torque. The degrees of freedom are limited. To ensure the stability of the body, the configuration change is generally very slow, which makes it difficult to meet the requirements of effective interaction between the robot and the environment. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of existing self-reconfigurable modular robots that rely too much on joint movement and have poor flexibility after connection, and to provide a modular self-reconfigurable robot connection and reconstruction method. Through the mutual position recognition of the camera device and the DPM code, the male and female heads of the robot are automatically connected. After connection, they act as a moving joint, and the propeller of the robot generates thrust to assist the movement of the robot, avoid the servo at the joint from bearing the load alone, reduce the load at the joint, and increase the flexibility of movement.

[0005] To achieve the above objectives, the technical solutions provided by the present invention are:

[0006] A modular self-reconfigurable robot connection and reconfiguration method is unique in that it is implemented using a reconfigurable modular robot structure; the reconfigurable modular robot structure includes a PC host and several robots; each robot includes a body, a battery, a main control module, a propeller assembly, an omnidirectional wheel drive assembly, an IMU six-axis sensor, a docking module, and a camera device;

[0007] The omnidirectional drive module is located on the back of the fuselage; the omnidirectional drive module includes omnidirectional wheel drive components radially distributed on the edge of the back of the fuselage, which are used to drive the robot to move;

[0008] The propeller assembly is installed at the center of the fuselage and is used to generate upward or downward thrust;

[0009] The battery, main control module and docking module are arranged on the front of the fuselage; the battery is used to supply power to the main control module, propeller assembly, omni-directional wheel drive assembly and docking module;

[0010] 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 edge of the fuselage. The female docking device, the first male docking device, and the second male docking device are each provided with a DPM code. The female docking device of one robot can be plugged into or mated with the first male docking device or the second male docking device of any other robot to achieve a connection between the robots. The female docking device is provided with a camera device for identifying the DPM code on the first male docking device and the second male docking device of another robot.

[0011] 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;

[0012] 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 control module;

[0013] The main control module is wirelessly connected to the PC host via WIFI, and can calculate the robot's own position information based on the robot's angular acceleration and acceleration measured by the IMU six-axis sensor and upload it to the PC host. It can also control the rotation angle of the first male docking device and the second male docking device, the rotation speed of the omnidirectional drive module and the propeller assembly according to the connection command or reconstruction command sent by the PC host;

[0014] The PC host has a DPM code database containing robot numbers, and each robot has a unique DPM code. The PC host can search the database based on the received real-time position information of the robot and send a reconstruction action instruction to the robot main control module based on the search result.

[0015] The modular self-reconfigurable robot connection and reconstruction method comprises the following steps:

[0016] Step 1: The PC host outputs the robot connection command. The main control modules of the two robots output PWM signals according to the received connection command to control the movement of the omnidirectional wheel drive components in their respective omnidirectional drive modules.

[0017] Step 2: The IMU six-axis sensors in the two robots transmit the measured position information of each robot to their respective main control modules in real time. The main control modules upload the received position information to the PC host. The PC host determines whether the distance and angle meet the preset requirements. If so, step 3 is executed. Otherwise, the PC host continues to send movement instructions to the main control modules of the robots. The main control modules control the movement of the robots until the camera device on the female docking device of the first robot can capture the DPM code image of the first male docking device or the second male docking device of the second robot.

[0018] Step 3: The camera on the female docking device of the first robot captures and decodes the DPM code on the first male docking device or the second male docking device of the second robot. The decoded result is compared with the robot's own position information measured by the IMU six-axis sensor to obtain the actual relative position information of the two connected robots.

[0019] The camera device and the IMU six-axis sensor upload the actual relative position information of the two robots to their respective main control modules, and communicate with each other through Wi-Fi to achieve position information sharing;

[0020] Step 4: The robot main control module sends PWM signals to the respective omnidirectional drive modules based on the actual relative position information of the two robots, controlling the movement of the omnidirectional wheel drive components. The two robots continue to approach each other until they reach the preset initial connection position.

[0021] Step 5: The main control module of the first robot controls its female docking device to unlock, and the main control modules of the two robots continue to control the two robots to move closer to each other. The camera device collects the DPM code and uploads it to the main control module. The main control module determines whether the relative positions of the two robots meet the preset successful connection position requirements. If so, the main control module of the first robot outputs a PWM signal to control its female docking device to lock, and the two robots are reliably connected. Otherwise, the main control module continues to control the two robots to move closer to each other until the relative positions meet the preset successful connection position requirements.

[0022] Step 6: Complete the connection between other robots according to the process of steps 1 to 5 as needed.

[0023] Step 7: After the robot connection is completed, the PC host sends a reconstruction instruction according to the reconstruction requirement. The robot main control module outputs a PWM signal according to the reconstruction instruction to control the rotation of the corresponding female docking device and the first male docking device or the second male docking device. The configuration between the robots changes, the DPM code information is updated, and the IMU six-axis sensor measures the current position information of the robot and uploads it to the robot main control module. The main control module determines whether the robot has reached the preset reconstruction position. If so, the reconstruction is completed; otherwise, the robot main control module continues to output PWM signals to control the rotation of its female docking device and the first male docking device or the second male docking device until it reaches the preset reconstruction position.

[0024] At the same time, during the configuration change between robots, the robot main control module transmits the current relative position information of the robots to the PC host. The PC host calculates the propeller speed in the propeller assembly based on the position and posture of each robot and feeds it back to the main control module of the corresponding robot. The main control module adjusts the propeller thrust based on PID control to compensate for the torque required during the robot reconstruction movement.

[0025] Furthermore, 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 and the second male docking device of the other robot;

[0026] 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;

[0027] 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.

[0028] The electromagnetic relay can be activated by the high and low levels 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 is 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.

[0029] Furthermore, 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;

[0030] The first swing arm has a U-shaped structure, the center of the bottom of the first swing arm is connected to the output shaft of the first servo. The first swing arm rotates around the axis of the output shaft under the drive of the first servo, 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 are capable of plugging and mating with the U-shaped member and rectangular member of the female head of another robot female head docking device.

[0031] 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.

[0032] Furthermore, the second male docking device includes a second servo and a second swing arm, wherein the second swing arm comprises a U-shaped structure, wherein a side wall of the U-structure is symmetrically arranged relative to a bottom wall thereof, and an end of the side wall remote from the opening of the U-structure is connected to an output shaft of the second servo, wherein the axis of the output shaft of the second servo is parallel to the bottom wall of the U-structure of the second swing arm; the second swing arm swings around 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;

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

[0034] Furthermore, the omnidirectional wheel drive assembly includes a stepper motor, a stepper motor drive board and an omnidirectional wheel;

[0035] 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;

[0036] 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;

[0037] 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.

[0038] Furthermore, the propeller assembly includes a propeller and a propeller bracket;

[0039] The propeller bracket is arranged on the back of the fuselage and located in the middle of the fuselage;

[0040] The propeller includes a propeller controller, a propeller electronic controller, a propeller motor and blades;

[0041] The propeller electric regulator and the propeller motor are installed in the middle of the blade;

[0042] The blades are fixed to the propeller bracket, and the center of the propeller coincides with the center of the fuselage;

[0043] 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.

[0044] Furthermore, the specific process of step 3 is as follows:

[0045] Step 3.1: The camera device of the first robot captures the DPM code on the first male docking device or the second male docking device of the second robot, and transmits the obtained grayscale image of the DPM code of the second robot to its own main control module;

[0046] Step 3.2: The main control module performs binarization on the received grayscale image, constructs and updates the “line support region”; the constructed “line support region” is

[0047]

[0048] Among them, angle is the angle evaluation function, For adjacent pixels, τ = 22.5; θ region is the line support area angle, θ region Update according to the following formula:

[0049]

[0050] Where: ang i is the angle function value, i=1,2,3……;

[0051] Step 3.3: Fit the line support region to a rectangle according to the principle of minimizing the principal moment of inertia. Construct the NFA statistic to determine the straightness of the rectangle. Then, based on the LSD algorithm, gradually search to determine whether there is a linear feature L-shaped edge in the grayscale image. If so, proceed to step 3.4. Otherwise, return to step 3.2 and reprocess the image.

[0052] Step 3.4: Precisely locate the L-shaped edge of the linear feature by calculating the maximum value of the scan line gradient and perform distortion correction to obtain the track line boundary. Then determine whether the track line boundary contains track line features. If so, proceed to step 3.5. Otherwise, return to step 3.3 and re-search and determine based on the LSD algorithm.

[0053] Step 3.5: Binarize and midpoint sample the barcode image within the track line boundary obtained in step 3.4, divide the barcode image into modules using gradient features, and decode to obtain the ID information of the DPM code;

[0054] In step 3.6, the main control module uploads the decoding result to the PC host. The PC host searches the database to determine the robot corresponding to the DPM code, and compares the decoding result with the robot's own position information measured by the IMU six-axis sensor on the robot. If the difference between the two is less than the set threshold, the DPM code decoding result is taken as the actual relative position coordinates of the two connected robots; otherwise, the average value of the two is taken as the actual relative position coordinates of the two connected robots.

[0055] Furthermore, in step 3.6, the threshold is set to 1%.

[0056] Furthermore, the female docking device, the first male docking device, and the second male docking device are provided with magnetic contact connectors; the magnetic contact connectors are connected to the corresponding robot main control modules via cables; the magnetic contact connectors are used to enable information sharing between the robot main control modules during the robot reconstruction process, and the information includes relative position information between the robots;

[0057] In step 7, the PC host sends a reconstruction instruction to any robot main control module according to the reconstruction requirement. The robot main control modules share the reconstruction instruction through the magnetic contact connector and output a PWM signal according to the reconstruction instruction.

[0058] Furthermore, in step 7, the process in which the main control module adjusts the propeller thrust based on PID control is as follows:

[0059] Taking the propeller speed as the control object, the propeller thrust is adjusted using the following formula:

[0060]

[0061] Among them, u is the propeller speed PWM control signal output by the robot main control module, e is the speed under the predetermined thrust, K P ,K I ,K D They are the proportional control coefficient, integral control coefficient and differential control coefficient, which are obtained through propeller electrical adjustment.

[0062] The advantages of the present invention are:

[0063] The method of the present invention addresses the problems of large volume and weight, slow configuration transformation speed, and high load-bearing capacity of the mechanical connection devices used by modular self-reconfigurable robots when acting as joints. A connection and reconstruction method for modular self-reconfigurable robots is proposed. Through the fusion positioning of DPM code image recognition and IMU six-axis sensor measurement, the robot position can be quickly and accurately positioned, and the connection and reconstruction between robots can be realized.

[0064] The method of the present invention controls and adjusts the thrust of each propeller by controlling the propeller thrust, compensates for the torque of gravity on the joints during the robot reconstruction movement, enhances the flexibility of the robot, avoids the servos at the robot joints from bearing all the torque, and thus reduces the joint load.

[0065] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0067] Figure 1 : is a schematic diagram of the connection process of the modular self-reconfigurable robot in the present invention;

[0068] Figure 2 : It is a schematic diagram of the overall structure of a single robot;

[0069] Figure 3 : is a schematic diagram of the motion coordinate system in the omni-directional wheel drive assembly;

[0070] Figure 4 : This is the DPM code recognition process flow chart during the robot connection process;

[0071] Figure 5 : This is a flowchart of the modular self-reconfigurable robot after connection and reconstruction in the present invention;

[0072] Figure 6 : This is a schematic diagram of the process of connecting and reconstructing multiple robots across steps;

[0073] Figure 7 : It is a skeleton model diagram of multiple robots reconstructed.

[0074] In the figure: 1-servo, 2-swing arm, 3-airframe, 4-battery, 5-propeller assembly, 6-camera device, 7-female docking device, 8-magnetic contact connector, 9-movable pin, 10-electromagnet, 11-electromagnetic relay, 12-stepper motor, 13-omnidirectional wheel, 14-IMU six-axis sensor, 15-DPM code, 16-main control module. DETAILED DESCRIPTION

[0075] The following describes in detail embodiments of the present invention. The embodiments are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0076] Reference Figure 1-Figure 5 The modular self-reconfigurable robot connection and reconstruction method provided by the present invention is realized by using a reconfigurable modular robot structure. The reconfigurable modular robot structure includes a PC host and several robots; a single robot includes a fuselage 3, a battery 4, a propeller assembly 5, a camera device 6, an omni-directional wheel drive assembly 13, an IMU six-axis sensor 14, a main control module 16 and a docking module, and the docking module includes a female docking device 7, a first male docking device and a second male docking device, which are arranged at an angle of 120 degrees around the edge of the fuselage; the female docking device 7, the first male docking device and the second male docking device are all provided with a DPM code, and the female docking device of a robot can be plugged and matched with the first male docking device or the second male docking device of any robot to realize the connection between the robots; the female docking device is provided with a camera device 6 for identifying the DPM code 15 on the first male docking device and the second male docking device of another robot;

[0077] 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;

[0078] The IMU six-axis sensor 14 is used to measure the robot's angular acceleration and acceleration in real time and transmit them to the robot's main control module;

[0079] The main control module 16 is wirelessly connected to a PC host (not shown in the figure), and can calculate the robot's own position information based on the robot's angular acceleration and acceleration measured by the IMU six-axis sensor and upload it to the PC host. It can also control the rotation angle of the first male docking device and the second male docking device, the speed of the omnidirectional drive module and the propeller assembly according to the connection command or reconstruction command sent by the PC host;

[0080] A DPM code database containing robot numbers and relative position information is established in the PC host, and each robot has a unique DPM code; the PC host can search the database based on the received real-time position information of the robot and send reconstruction action instructions to the robot main control module based on the search results.

[0081] Specifically, the female docking device 7 includes a female head, a movable pin 9, an electromagnet bracket, an electromagnet 10 and an electromagnetic relay 11. The female head includes a rectangular part with a notch and a U-shaped part. The openings of the rectangular part and the U-shaped part are radially outward along the fuselage, and can be plugged and matched with the first male docking device and the second male docking device of other robots. The movable pin 9, the electromagnet bracket, the electromagnet and the electromagnetic relay are arranged on the side of the opening of the U-shaped part, and the rectangular part is located on the side of the closed end of the U-shaped part. The electromagnet is fixedly mounted on the surface of the fuselage through the 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. It can reciprocate along the mounting hole on the electromagnet without falling out.

[0082] The electromagnetic relay 11 can be activated by the high and low levels 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 is 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.

[0083] Specifically, the servo 1 includes a first servo and a second servo, and the swing arm 2 includes a first swing arm and a second swing arm. The first male docking device includes the first servo and the 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 first servo output shaft is radially aligned with the fuselage. The first swing arm is a U-shaped structure, with the center of its bottom connected to the output shaft of the first servo. Driven by the first servo, the first swing arm rotates about the axis of its output shaft, with the rotation plane of the first swing arm perpendicular to the plane of the front of the fuselage. The two open ends of the first swing arm are capable of plugging and mating with the U-shaped and rectangular components of the female docking device of another robot. A first positioning hole is defined on a side wall of the first swing arm, with the axis of the first positioning hole 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 to the female docking device of another robot by engaging with a movable pin of the female docking device after the first male docking device is docked with the female docking device of the other robot.

[0084] 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;

[0085] The second swing arm comprises a U-shaped structure, one side wall of which is symmetrically arranged relative to its bottom wall. One end of the side wall, away from the opening of the U-shaped structure, is connected to the output shaft of the second servo, and 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 around the axis of its output shaft under the drive of 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 mate with the U-shaped part and rectangular part of the female end of another robot's female end 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 end docking device to the female end docking device of another robot by cooperating with the movable pin of the female end docking device after the second male end docking device docks with the female end docking device of another robot.

[0086] Specifically, the omnidirectional wheel drive assembly includes a stepper motor 12, a stepper motor drive board, and an omnidirectional wheel 13. The omnidirectional wheel 13 comprises an omnidirectional wheel frame and omnidirectional wheel rollers. Multiple omnidirectional wheel rollers are evenly distributed around the circumference of the omnidirectional wheel frame and on the rim of the omnidirectional wheel frame. 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, with the omnidirectional wheel frame positioned toward the center of the fuselage, while the stepper motor is positioned away from the center of the fuselage. The stepper motor drive board is fixed to the back of the fuselage near the stepper motor and is used to control the speed and forward and reverse rotation of the stepper motor based on control signals sent by the main control module.

[0087] Specifically, the propeller assembly 5 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 speed controller, a propeller motor and a blade; the propeller electronic speed controller and the propeller motor are installed in the middle of the blade; the blade is fixed on 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 electronic speed controller to achieve precise control of the propeller motor speed.

[0088] The following is a detailed description of the modular self-reconfigurable robot connection and reconstruction method of the present invention.

[0089] Step 1: The PC host outputs the robot connection command. The main control modules of the two robots output PWM signals according to the received connection command to control the movement of the omnidirectional wheel drive components in their respective omnidirectional drive modules.

[0090] The PC host determines the two robots that need to be connected and calculates the required movement distance. The main control modules 16 of the two robots receive movement instructions from the PC host via 2.4G. When the robots are in an independent state, the robot main control module issues a command to allow the two robots to start connecting with each other, sending PWM signals to the servos on the robots to control the two connected robots. The movement of the robots is achieved by the movement of the omnidirectional wheel drive components of the robots. The movement algorithm of the robot omnidirectional wheel assembly is:

[0091]

[0092] Among them, v c is the velocity of the robot center, v cx and v cy v c Velocity components on the x and y axes, w c is the angular velocity of the robot center, w1, w2, and w3 are the angular velocities of the three omnidirectional wheels respectively, R is the distance from the center of the omnidirectional wheel to the center of the robot, and r is the radius of the omnidirectional wheel.

[0093] In step 2, the six-axis IMU sensors in both robots transmit their measured position information to their respective main control modules in real time. The main control modules then upload this information to the host PC, which determines whether the distance and angle meet preset requirements. If so, step 3 is executed. Otherwise, the PC continues to send movement commands to the main control modules, which control the robots' movements until the camera on the first robot's female docking device captures the DPM code image of either the first or second male docking device of the second robot. At this point, the electromagnet on the reconstructed female end begins to operate, pulling the movable pin out of its mating position and preparing for docking.

[0094] Step 3: The camera on the female docking device of the first robot collects and decodes the DPM code on the first male docking device or the second male docking device of the second robot, and compares the decoding result with the robot's own position information measured by the IMU six-axis sensor to obtain the actual relative position coordinates of the two robots connected to each other; the camera and IMU six-axis sensor upload the actual position information of the two robots to their respective main control modules to achieve position information sharing. For the specific process, refer to Figure 4 ,as follows:

[0095] Step 3.1: The camera device of the first robot captures the DPM code on the first male docking device or the second male docking device of the second robot, and transmits the obtained grayscale image of the DPM code of the second robot to its own main control module.

[0096] In step 3.2, the robot main control module performs binarization on the received grayscale image and constructs and updates the "line support region" according to the following formula:

[0097]

[0098] Among them, angle is the angle evaluation function, are adjacent pixels, θ region is the line support area angle, τ = 22.5;

[0099] θ region Update according to the following formula:

[0100]

[0101] In the formula, ang i is the angle function value, i=1,2,3……;

[0102] In step 3.3, the line support region is fitted into a rectangle according to the principle of minimum principal moment of inertia, and the NFA statistic is constructed to determine the straightness of the rectangle. Based on the LSD algorithm, a step-by-step search is performed to determine whether there is a linear feature L-shaped edge in the grayscale image. If so, proceed to step 3.4. Otherwise, return to step 3.2 and reprocess the image. Specifically:

[0103] According to the principle of minimum principal moment of inertia, the line support area is fitted into a rectangle, and the statistical NFA is constructed to determine the straightness of the rectangle:

[0104]

[0105] in, The probability that the number of homogeneous points in the corresponding region r in the created noise image I is greater than k(r, i), N test is the number of rectangles that may exist in the created noise image I.

[0106] For the detected image of N×M pixels, since k(r, I) ≥ k(r, i) obeys the binomial distribution, we have:

[0107]

[0108] Wherein, γ is a correction factor, γ=11; when NFA<1, the rectangular area is considered to be a straight line with a confidence level of 1.

[0109] When two straight lines are detected to intersect, the intersection point is P2, which is also the vertex of the two straight lines. The other two vertices of the two straight lines are P1 and P3 respectively. Calculate the center P0 of the two straight lines. If:

[0110]

[0111] It is considered that the L-shaped edge of the DPM code is identified.

[0112] In step 3.4, the positioning boundary of the L-shaped edge of the straight line feature is precisely located by calculating the maximum value of the scan line gradient, and distortion correction is performed to obtain the track line boundary. It is also determined whether there is a track line feature on the track line boundary. If so, execute step 3.5. Otherwise, return to step 3.3 and re-search and judge based on the LSD algorithm.

[0113] Since all DPM codes are set to black, the boundary can be accurately located by calculating the maximum value of the scan line gradient. Since the side length of the DPM code is fixed and the internal and external parameters of the camera are fixed and known, the actual position of the DPM code can be obtained:

[0114]

[0115] Among them, x r ,y r ,z r is the real coordinate of the robot whose DPM code is recognized, x w ,y w ,z w is the real world coordinate, x m ,y m ,z m is the coordinate of the DPM code in the image, M m,w is the homogeneous transformation matrix, M r,m is the homogeneous transformation matrix of the robot center relative to the DPM code.

[0116] Step 3.5: Binarize and midpoint sample the barcode image within the track line boundary obtained in step 3.4, divide the barcode image into modules using gradient features, and decode to obtain the ID information of the DPM code.

[0117] In step 3.6, the main control module uploads the decoding result to the PC host. The PC host searches the database to determine the robot corresponding to the DPM code, and compares the decoding result with the robot's own position information measured by the IMU six-axis sensor on the robot. If the difference between the two is less than the set threshold, the DPM code decoding result is taken as the actual relative position coordinates of the two connected robots; otherwise, the average value of the two is taken as the actual relative position coordinates of the two connected robots.

[0118] The Euler angle of the body posture is θ,χ, the angular rate calculated by the IMU six-axis sensor is p,q,r, and x w ,y w ,z w The attitude angle change rate of the same coordinate system is There are attitude motion equations

[0119]

[0120] And there are relative positions:

[0121]

[0122] Among them, T is the transformation matrix between the coordinates of the two robots, X, Y, Z are the coordinates of the robot to be identified, and the dynamic relative position of the two robots is obtained.

[0123] In step 4, the dynamic relative position information of the two robots is transmitted to the main control modules of the two robots, which send PWM signals to their respective omnidirectional drive modules to control the movement of the omnidirectional wheel drive components. The two robots continue to approach each other until they reach the preset initial connection position.

[0124] Step 5: The main control module of the first robot controls its female docking device to unlock, and the main control modules of the two robots continue to control the two robots to approach each other. The camera device collects the DPM code and uploads it to its main control module. The main control module determines whether the relative positions of the two robots meet the preset connection success position requirements. If so, the main control module of the first robot outputs a PWM signal to control its female docking device to lock, and the electromagnet at the female end participating in the reconstruction stops working, and the movable pin bounces back to its original position, completing the cooperation with the swing arm positioning hole at the male end participating in the reconstruction, and the two robots are reliably connected; otherwise, the main control module continues to control the two robots to approach each other until the relative positions meet the preset connection success position requirements.

[0125] Step 6: Based on actual needs, follow the process from step 1 to step 5 to complete the interconnection between multiple other robots.

[0126] Step 7. After multiple robots are connected, the PC host sends a reconstruction command according to the reconstruction requirements. The robot main control module outputs a PWM signal according to the reconstruction command to control the rotation of the servo, thereby swinging the swing arm. The robot's configuration changes, the DPM code information is updated, and the IMU six-axis sensor measures the robot's current position information and uploads it to the robot main control module. The main control module determines whether the robot has reached the preset reconstruction position. If so, the reconstruction is completed; otherwise, the robot main control module continues to output PWM signals to control the rotation of its female docking device and the first male docking device or the second male docking device until the preset reconstruction position is reached. Figure 6 The process of connecting and reconstructing four robots across steps is shown.

[0127] During the reconstruction process, whenever the robot's configuration changes, the robot's main control module transmits the current robot's relative position information to the PC host via 2.4G. The PC host adjusts the propeller thrust based on PID control according to each robot's position and posture to compensate for the torque required during the robot's reconstruction movement. The propeller speed is calculated using the following algorithm:

[0128] Reference Figure 7 , define the robot at any position, starting from the robot touching the ground as zero, and the propeller thrust is f i , the torque generated is τ i ,have:

[0129]

[0130] The superscript R refers to the relative coordinate system between robots, p i is the propeller position.

[0131] The friction force generated by the omnidirectional wheel contacting the ground is F. When there are N+1 robots in total, the torque force between the male and female ends of the i+1th robot and the i-th robot is:

[0132]

[0133] Among them, q i is the position of the i+1th robot relative to the ith robot in the coordinate system (x r ,y r ,z r ), mg is the gravity of any robot, τ is the torque of the servo at the male and female ends of the docking, and a is taken as follows according to the different male ends of the docking:

[0134]

[0135] Wherein, pitch direction refers to the direction of rotation around the X-axis, and roll direction refers to the direction of rotation around the Z-axis.

[0136] The propeller speed is controlled to reduce the torque and force at the robot joints. The following control methods are available based on PID:

[0137]

[0138] Among them, u is the propeller speed PWM control signal output by the robot main control module, e is the speed under the predetermined thrust, K P ,K I ,K D They are respectively the proportional control coefficient, the integral control coefficient and the differential control coefficient, which are obtained through propeller electrical adjustment.

[0139] The PC host transmits the speed signal back to the robot's main control module via 2.4G. The robot's main control module then outputs a PWM signal to the propeller electronic speed controller, controlling the propeller speed and generating thrust. During the robot's reconfiguration process, the thrust of each propeller continuously changes, compensating for the torque on the joints due to gravity and enhancing the robot's flexibility.

[0140] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present invention, and these modifications or replacements should all be included in the scope of protection of the present invention.

Claims

1. A modular self-reconfigurable robot connection and reconstruction method, characterized in that: This is achieved using a reconfigurable modular robot structure; the reconfigurable modular robot structure includes a PC host and several robots; a single robot includes a body, a battery, a main control module, a propeller assembly, an omnidirectional wheel drive assembly, an IMU six-axis sensor, a docking module, and a camera device; The omnidirectional drive module is located on the back of the fuselage; the omnidirectional drive module includes omnidirectional wheel drive components radially distributed on the edge of the back of the fuselage, which is used to drive the robot to move; The propeller assembly is installed at the center of the fuselage and is used to generate upward or downward thrust; The battery, main control module and docking module are arranged on the front of the fuselage; the battery 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 edge of the fuselage. The female docking device, the first male docking device, and the second male docking device are each provided with a DPM code. The female docking device of one robot can be plugged into or mated with the first male docking device or the second male docking device of any other robot to achieve a connection between the robots. The female docking device is provided with a camera device for identifying the DPM code on the first male docking device and the second male docking device of another robot. 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 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 control module; The main control module is wirelessly connected to the PC host via WIFI, and can calculate the robot's own position information during movement based on the robot's angular acceleration and acceleration measured by the IMU six-axis sensor and upload it to the PC host. It can also control the rotation angle of the first male docking device and the second male docking device, and the rotation speed of the omnidirectional drive module and the propeller assembly according to the connection command or reconstruction command sent by the PC host; The PC host has a DPM code database containing robot numbers, and each robot has a unique DPM code. The PC host can search the database based on the received real-time position information of the robot and send a reconstruction action instruction to the robot main control module based on the search result. The modular self-reconfigurable robot connection and reconstruction method comprises the following steps: Step 1: The PC host outputs the robot connection command. The main control modules of the two robots output PWM signals according to the received connection command to control the movement of the omnidirectional wheel drive components in their respective omnidirectional drive modules. Step 2: The IMU six-axis sensors in the two robots transmit the measured position information of each robot to their respective main control modules in real time. The main control modules upload the received position information to the PC host. The PC host determines whether the distance and angle meet the preset requirements. If so, step 3 is executed. Otherwise, the PC host continues to send movement instructions to the main control modules of the robots. The main control modules control the movement of the robots until the camera device on the female docking device of the first robot can capture the DPM code image of the first male docking device or the second male docking device of the second robot. Step 3: The camera on the female docking device of the first robot captures and decodes the DPM code on the first male docking device or the second male docking device of the second robot. The decoded result is compared with the robot's own position information measured by the IMU six-axis sensor to obtain the actual relative position information of the two connected robots. The camera device and the IMU six-axis sensor upload the actual relative position information of the two robots to their respective main control modules, and communicate with each other through Wi-Fi to achieve position information sharing; Step 4: The robot main control module sends PWM signals to the respective omnidirectional drive modules based on the actual relative position information of the two robots, controlling the movement of the omnidirectional wheel drive components. The two robots continue to approach each other until they reach the preset initial connection position. Step 5: The main control module of the first robot controls its female docking device to unlock, and the main control modules of the two robots continue to control the two robots to move closer to each other. The camera device collects the DPM code and uploads it to the main control module. The main control module determines whether the relative positions of the two robots meet the preset successful connection position requirements. If so, the main control module of the first robot outputs a PWM signal to control its female docking device to lock, and the two robots are reliably connected. Otherwise, the main control module continues to control the two robots to move closer to each other until the relative positions meet the preset successful connection position requirements. Step 6: Complete the connection between other robots according to the process of steps 1 to 5 as needed. Step 7: After the robot connection is completed, the PC host sends a reconstruction instruction according to the reconstruction requirement. The robot main control module outputs a PWM signal according to the reconstruction instruction to control the rotation of the corresponding female docking device and the first male docking device or the second male docking device. The configuration between the robots changes, the DPM code information is updated, and the IMU six-axis sensor measures the current position information of the robot and uploads it to the robot main control module. The main control module determines whether the robot has reached the preset reconstruction position. If so, the reconstruction is completed; otherwise, the robot main control module continues to output PWM signals to control the rotation of its female docking device and the first male docking device or the second male docking device until it reaches the preset reconstruction position. At the same time, during the configuration change between robots, the robot main control module transmits the current relative position information of the robots to the PC host. The PC host calculates the propeller speed in the propeller assembly based on the position and posture of each robot and feeds it back to the main control module of the corresponding robot. The main control module adjusts the propeller thrust based on PID control to compensate for the torque required during the robot reconstruction movement.

2. A modular self-reconfigurable robot connection and reconstruction method 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 and the second male docking device of the other 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 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 is 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. A modular self-reconfigurable robot connection and reconstruction method 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 has a U-shaped structure, the center of the bottom of the first swing arm is connected to the output shaft of the first servo. The first swing arm rotates around the axis of the output shaft under the drive of the first servo, 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 are capable of plugging and mating with the U-shaped member and rectangular member of the female head of 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. A modular self-reconfigurable robot connection and reconstruction method according to claim 3, characterized in that: The second male docking device includes a second servo and a second swing arm. The second swing arm comprises a U-shaped structure, with one side wall of the U-shaped structure symmetrically arranged relative to its bottom wall. An end of the side wall, distal to the opening of the U-shaped structure, is connected to the output shaft of the second servo. 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 around the axis of its 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 part and the rectangular part of the female head in the female docking device of another robot; 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. A modular self-reconfigurable robot connection and reconstruction method according to claim 1, 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. A modular self-reconfigurable robot connection and reconstruction method according to claim 1, 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. A modular self-reconfigurable robot connection and reconstruction method according to claim 1, characterized in that: The specific process of step 3 is as follows: Step 3.1: The camera device of the first robot captures the DPM code on the first male docking device or the second male docking device of the second robot, and transmits the obtained grayscale image of the DPM code of the second robot to its own main control module; Step 3.2: The main control module performs binarization on the received grayscale image, constructs and updates the "line support region"; The constructed "line support region" is Among them, angle is the angle evaluation function, For adjacent pixels, τ = 22.5; θ region is the line support area angle, θ region Update according to the following formula: Where: ang i is the angle function value, i=1,2,3……; Step 3.3: Fit the line support region to a rectangle according to the principle of minimizing the principal moment of inertia. Construct the NFA statistic to determine the straightness of the rectangle. Then, based on the LSD algorithm, gradually search to determine whether there is a linear feature L-shaped edge in the grayscale image. If so, proceed to step 3.

4. Otherwise, return to step 3.2 and reprocess the image. Step 3.4: Precisely locate the L-shaped edge of the linear feature by calculating the maximum value of the scan line gradient and perform distortion correction to obtain the track line boundary. Then determine whether the track line boundary contains track line features. If so, proceed to step 3.

5. Otherwise, return to step 3.3 and re-search and determine based on the LSD algorithm. Step 3.5: Binarize and midpoint sample the barcode image within the track line boundary obtained in step 3.4, divide the barcode image into modules using gradient features, and decode to obtain the ID information of the DPM code; In step 3.6, the main control module uploads the decoding result to the PC host. The PC host searches the database to determine the robot corresponding to the DPM code, and compares the decoding result with the robot's own position information measured by the IMU six-axis sensor on the robot. If the difference between the two is less than the set threshold, the DPM code decoding result is taken as the actual relative position coordinates of the two connected robots; otherwise, the average value of the two is taken as the actual relative position coordinates of the two connected robots.

8. A modular self-reconfigurable robot connection and reconstruction method according to claim 7, characterized in that: In step 3.6, the threshold is set to 1%.

9. A modular self-reconfigurable robot connection and reconstruction method according to claim 1, characterized in that: The female docking device, the first male docking device, and the second male docking device are provided with magnetic contact connectors; the magnetic contact connectors are connected to the corresponding robot main control modules via cables; the magnetic contact connectors are used to enable information sharing between the robot main control modules during the robot reconstruction process, and the information includes relative position information between the robots; In step 7, the PC host sends a reconstruction instruction to any robot main control module according to the reconstruction requirement. The robot main control modules share the reconstruction instruction through the magnetic contact connector and output a PWM signal according to the reconstruction instruction.

10. A modular self-reconfigurable robot connection and reconstruction method according to claim 1, characterized in that: In step 7, the process in which the main control module adjusts the propeller thrust based on PID control is as follows: Taking the propeller speed as the control object, the propeller thrust is adjusted using the following formula: Among them, u is the propeller speed PWM control signal output by the robot main control module, e is the speed under the predetermined thrust, K P ,K I ,K D They are the proportional control coefficient, integral control coefficient and differential control coefficient, which are obtained through propeller electrical adjustment.

Images