A multi-link active-passive articulated pipeline inspection robot

Abstract

The application provides a multi-link active and passive joint type pipeline detection robot, and relates to the technical field of robots.The robot comprises a first cabin body, a second cabin body, a third cabin body and a fourth cabin body which are sequentially hinged; a driving assembly which is arranged in the third cabin body and connected to an active joint; and a controller which is connected to the driving assembly and configured to acquire motion parameters of the active joint, calculate expected reference force of the active joint based on the motion parameters, determine joint driving force control values based on the expected reference force, and drive the active joint by using the driving assembly based on the joint driving force control values to change the angle between the second cabin body and the third cabin body, so that the pipeline detection robot is attached to the inner wall of a pipeline to be detected, thereby solving the problems of insufficient traction of the pipeline detection robot, difficulty in moving in the pipeline, and difficulty in adapting to different pipeline diameters and corresponding pipelines with vertical T-shaped branch structures.

Description

Technical Field

[0001] This application relates to the field of robotics technology, and in particular to a multi-link active and passive joint type pipeline inspection robot. Background Technology

[0002] In modern industry, especially in sectors like oil and gas, pipeline systems are crucial for transporting media, and their safe and stable operation is paramount. With the continuous expansion of pipeline construction and the increasing complexity of pipelines, more stringent requirements are being placed on pipeline inspection and maintenance. Due to the complex environment in which pipelines operate, manual inspection is not only inefficient but also poses numerous safety hazards. Therefore, utilizing robotics to automate pipeline inspection has become an inevitable trend. However, the complex operating conditions of pipelines, such as bends, T-shaped pipes, and geometrically irregular pipelines, present significant challenges to the application of robotics.

[0003] To address these challenges, current efforts are focused on optimizing the robot's mechanical structure to enable it to adapt to complex pipeline conditions, such as T-shaped pipes and bends, and to achieve a certain degree of movement within the pipeline. Other approaches emphasize improving the robot's drive mechanism by employing a composite drive mode to provide power, thereby enhancing the robot's mobility within the pipeline.

[0004] However, the current robots suffer from insufficient traction. When the inner wall of the pipe is smooth, the robot has difficulty increasing traction, making it difficult to move inside the pipe and affecting the detection efficiency. Secondly, the adaptability is poor. Existing robots cannot flexibly adapt to different pipe diameters and complex structures such as vertical T-shaped branches, which greatly limits their application range. In addition, it is difficult to calculate the load on the robot joints and wheels. Relying solely on position sensors cannot accurately calculate the load applied to the joints and wheels, which is not conducive to the precise control and timely adjustment of the robot's motion state. Summary of the Invention

[0005] This application provides a multi-link active and passive articulated pipe inspection robot to solve the technical problems of existing pipe inspection robots having insufficient traction force, difficulty in moving inside pipes, and difficulty in navigating pipes with different diameters and vertical T-shaped branch structures.

[0006] This application provides a multi-link active and passive articulated pipeline inspection robot, including: The first, second, third, and fourth compartments are hinged together in sequence; The first compartment and the second compartment, as well as the third compartment and the fourth compartment, are hinged together by a passive joint; the second compartment and the third compartment are hinged together by an active joint. A drive assembly is disposed within the third chamber and connected to the active joint; A controller, connected to the drive assembly, is further configured to: Obtain the motion parameters of the active joint; the motion parameters include: actual displacement, velocity, and angular acceleration; Based on the motion parameters, the expected reference force of the active joint is calculated; Based on the desired reference force, determine the joint driving force control value; Based on the joint drive force control value, the active joint is driven by the drive component to change the angle between the second chamber and the third chamber, so that the pipeline inspection robot fits against the inner wall of the pipeline to be tested.

[0007] In some embodiments, the first, second, third, and fourth compartments are interconnected in an M-shape; omnidirectional wheels are provided at the hinges between the first and second compartments, the second and third compartments, and the third and fourth compartments; the omnidirectional wheels are disposed opposite to each other on both sides of the second and third compartments; hemispherical wheels are provided on the side of the first compartment away from the second compartment and on the side of the fourth compartment away from the third compartment; The drive assembly is used to drive the active joint to change the angle between the second chamber and the third chamber, so that the omnidirectional wheel is in contact with the inner wall of the pipe to be tested; the first chamber and the second chamber, as well as the third chamber and the fourth chamber, are connected by a passive joint, so that the joint angle between the first chamber and the second chamber, as well as the third chamber and the fourth chamber, is equal to the joint angle between the second chamber and the third chamber.

[0008] In some embodiments, the active joint includes: A driven shaft is fitted with a transmission cylinder, a first cylindrical gear, and a second cylindrical gear; the transmission cylinder meshes with the second cylindrical gear and is connected to the second compartment; the first cylindrical gear is connected to the third compartment; the second cylindrical gear meshes with a transmission gear, and the transmission gear meshes with the drive gear of the drive assembly; Specifically, starting the drive assembly utilizes the drive gear to drive the second cylindrical gear to rotate; the rotation of the second cylindrical gear drives the transmission cylinder to rotate, thereby driving the second cabin to rotate.

[0009] In some embodiments, the active joint further includes: A rubber spring is located between the second compartment and the third compartment; the rubber spring is disposed opposite to each other on both sides of the second cylindrical gear, with one end of the rubber spring on one side of the second cylindrical gear connected to the second cylindrical gear and the other end connected to the second compartment; one end of the rubber spring on the other side of the second cylindrical gear is connected to the second cylindrical gear and the other end is connected to the third compartment; When the second cylindrical gear rotates, the third compartment rotates simultaneously via the rubber spring.

[0010] In some embodiments, the passive joint includes: A power shaft is provided, which is connected to the omnidirectional wheel located between the first compartment and the second compartment, as well as between the third compartment and the fourth compartment. A power gear is mounted on the power shaft, and the power gear is connected to a second motor, which is located within the second compartment and the third compartment.

[0011] In some embodiments, the passive joint further includes: A torsion spring, one end of which is connected to the first compartment and the other end of which is connected to the second compartment, is located between the first compartment and the second compartment; a torsion spring, one end of which is connected to the third compartment and the other end of which is connected to the fourth compartment, is located between the third compartment and the fourth compartment; the torsion spring located between the first compartment and the second compartment has the same torque as the torsion spring located between the third compartment and the fourth compartment; When the omnidirectional wheel and the hemispherical wheel are located in the same axial direction, the joint angles between the first compartment and the second compartment, the second compartment and the third compartment, and the third compartment and the fourth compartment are equal.

[0012] In some embodiments, the multi-link active-passive articulated pipeline inspection robot further includes: The third motor is located inside the first and fourth compartments on the side near the hemispherical wheel, and the power end of the third motor is connected to the hemispherical wheel; the third motor is used to drive the pipeline inspection robot to rotate along the tumbling axis.

[0013] In some embodiments, the multi-link active-passive articulated pipeline inspection robot further includes: An image acquisition device and a controller are provided, wherein the controller is connected to the image acquisition device and the third motor, the image acquisition device is located on the outside of the first chamber, and the image acquisition device is used to acquire images of the pipe to be tested; The controller is configured to: Based on the image, the direction of the pipeline is identified using the histogram method to obtain pipeline direction information. The third motor is then used to drive the hemispherical wheel to rotate along the rolling axis so that the axis of the pipeline under test is located within the gap between the hemispherical wheels.

[0014] In some embodiments, the multi-link active-passive articulated pipeline inspection robot further includes: An angle sensor, disposed within the second compartment, is connected to the active joint and the controller. The angle sensor is used to acquire the joint angle between the second and third compartments. The controller is further configured to: Based on the angle, the motion parameters of the active joint are calculated; the actual displacement is: ; In the formula, For joint angle; Represented as the inverse kinematics solution of the robot; The speed is: ; In the formula, Represented as a Jacobian matrix; Joint angular velocity; The angular acceleration is: ; In the formula, This is the joint angular acceleration.

[0015] In some embodiments, the desired reference force is: ; In the formula, , , These are the parameters of the desired impedance model; , , These are the actual displacement, velocity, and angular acceleration of the active joint, respectively. , , These are the reference displacement, velocity, and angular acceleration of the active joint, respectively. The controller is further configured to: Based on the desired reference force, a desired impedance model is obtained; the desired impedance model is used to determine the force provided by the joint; the force provided by the joint is: ; In the formula, The velocity is represented by the first derivative; Acceleration represented as the second derivative; Based on the expected reference force, determine the reference value of the joint driving force; Based on the force provided by the joint, determine the joint driving force mapping value; Based on the joint driving force reference value and the joint driving force mapping value, the joint driving force control value is determined.

[0016] This application provides a multi-link active-passive articulated pipe inspection robot, comprising: a first chamber, a second chamber, a third chamber, and a fourth chamber hinged sequentially; the first chamber and the second chamber, as well as the third chamber and the fourth chamber, are hinged together by a passive joint; the second chamber and the third chamber are hinged together by an active joint; a drive assembly disposed within the third chamber and connected to the active joint; and a controller connected to the drive assembly, the controller being configured to: acquire motion parameters of the active joint; the motion parameters including: actual displacement, velocity, and angular acceleration; calculate a desired reference force of the active joint based on the motion parameters; determine a joint driving force control value based on the desired reference force; and, based on the joint driving force control value, drive the active joint using the drive assembly to change the angle between the second chamber and the third chamber, causing the pipe inspection robot to conform to the inner wall of the pipe to be inspected, thereby improving the traction force of the pipe inspection robot; and enabling it to adapt to pipes with different diameters and vertical T-shaped branch structures. Attached Figure Description

[0017] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the multi-link active-passive articulated pipeline inspection robot in this application at one angle. Figure 2 This is a structural schematic diagram of the multi-link active-passive articulated pipeline inspection robot in this application from another angle. Figure 3 This is a cross-sectional view of the active joint in this application; Figure 4 This is a cross-sectional view of the passive joint in this application; Figure 5 This is a schematic diagram of the structure of the driver component in this application; Figure 6 This is an exploded view of the hull in this application; Figure 7This is a schematic diagram of the hemispherical wheel in this application; Figure 8 This is the joint force control logic diagram of the pipeline inspection robot in this application.

[0019] Explanation of reference numerals in the attached figures: 1-First compartment; 2-Second compartment; 3-Third compartment; 4-Fourth compartment; 5-Omnidirectional wheel; 6-Hemispherical wheel; 61-Third motor; 7-Passive joint; 71-Drive shaft; 72-Drive gear; 73-Second motor; 74-Torsion spring; 8-Active joint; 81-Driven shaft; 82-Transmission cylinder; 83-First cylindrical gear; 84-Second cylindrical gear; 85-Rubber spring; 86-Angle sensor; 9-Drive assembly; 91-Drive gear; 92-Transmission gear; 10-Image acquisition device. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0021] For example, current pipeline inspection robots have the following drawbacks: 1. Insufficient traction: Existing robots have insufficient traction in pipes, especially when the inner wall is smooth, and cannot effectively increase traction.

[0022] 2. Poor adaptability: It has difficulty adapting to different pipe diameters and vertical T-shaped branches, which limits the application range of the robot.

[0023] 3. Difficulty in estimating loads on joints and wheels: Using position sensors alone cannot effectively estimate the loads applied to joints and wheels.

[0024] To address the technical problems of insufficient traction force in pipeline inspection robots, making them difficult to move within pipelines, and their inability to adapt to pipelines with different diameters and vertical T-shaped branch structures, this application provides a multi-link active-passive articulated pipeline inspection robot. The multi-link active-passive articulated pipeline inspection robot is described below: like Figure 1 and Figure 2 The diagram shown is a structural schematic of the multi-link active-passive articulated pipeline inspection robot of this application.

[0025] This application provides a multi-link active and passive articulated pipeline inspection robot, including: A first compartment 1, a second compartment 2, a third compartment 3, and a fourth compartment 4 are sequentially hinged together; the first compartment 1, the second compartment 2, the third compartment 3, and the fourth compartment 4 are interconnected in an M-shape; omnidirectional wheels 5 are provided between the first compartment 1 and the second compartment 2, the second compartment 2 and the third compartment 3, and the third compartment 3 and the fourth compartment 4; the omnidirectional wheels 5 are positioned opposite each other on both sides of the second compartment 2 and the third compartment 3; hemispherical wheels 6 are provided on the side of the first compartment 1 away from the second compartment 2 and on the side of the fourth compartment 4 away from the third compartment 3.

[0026] For example, the hemispherical wheel 6 has a hemispherical structure, such as... Figure 7 As shown, the two hemispherical structures are connected by a shaft, with the ends fixed by limit screws. Washers are placed inside the limit screws to secure the two hemispheres. Bearings connect both ends of the connecting shaft to reduce the overall friction coefficient. A connecting sleeve separates the two hemispheres, allowing the entire structure to operate smoothly. The output shaft of the geared motor is fixed with set screws, and the output shaft connector is fixed to the hemispherical connecting shaft. The third motor 61 is fixed to the end of the cabin, as shown... Figure 6 As shown, a hemispherical running device is used to drive the robot. This device can roll along the tube's axis and rotate around its circumference. This allows the robot to roll laterally along its tumbling axis, changing the "W"-shaped structure's posture within the tube to adapt to bends and T-shaped sections. The entire hemispherical structure can be manufactured using 3D printing technology.

[0027] The first compartment 1 and the second compartment 2, as well as the third compartment 3 and the fourth compartment 4, are hinged together by a passive joint 7; the second compartment 2 and the third compartment 3 are hinged together by an active joint 8, wherein the active joint 8 is a DEA unit.

[0028] like Figure 3 The image shown is a cross-sectional view of the active joint 8 in this application (along...). Figure 2 (Cross-section view along the AA direction).

[0029] Specifically, the active joint 8 includes: Driven shaft 81, on which a transmission cylinder 82, a first cylindrical gear 83, and a second cylindrical gear 84 are mounted; the transmission cylinder 82 meshes with the second cylindrical gear 84, and the transmission cylinder 82 is connected to the second compartment 2; the first cylindrical gear 83 is connected to the third compartment 3; the second cylindrical gear 84 meshes with a transmission gear 92, and the transmission gear 92 meshes with the drive gear 91 of the drive assembly 9.

[0030] Specifically, starting the drive assembly 9 utilizes the drive gear 91 to drive the second cylindrical gear 84 to rotate; the rotation of the second cylindrical gear 84 drives the transmission cylinder 82 to rotate, thereby driving the second cabin 2 to rotate.

[0031] The active joint 8 also includes: A rubber spring 85 is located between the second compartment 2 and the third compartment 3. The rubber spring 85 is disposed opposite to each other on both sides of the second cylindrical gear 84. One end of the rubber spring 85 located on one side of the second cylindrical gear 84 is connected to the second cylindrical gear 84, and the other end is connected to the second compartment 2. One end of the rubber spring 85 located on the other side of the second cylindrical gear 84 is connected to the second cylindrical gear 84, and the other end is connected to the third compartment 3.

[0032] When the second cylindrical gear 84 rotates, the third compartment 3 rotates simultaneously via the rubber spring 85. The joint portion adopts a rubber spring structure, allowing the joint to actively adjust the included angle while corresponding joint units are positioned between the two intermediate compartments. The torsional torque, its initial angle, and the stiffness of the rubber spring determine the state of the joint's contact with the tube wall.

[0033] A drive assembly 9 is disposed inside the third chamber 3 and connected to the active joint 8. The drive assembly 9 is used to drive the active joint 8 to change the angle between the second chamber 2 and the third chamber 3, so that the omnidirectional wheel 5 is in contact with the inner wall of the pipe to be tested.

[0034] like Figure 5 The diagram shown is a schematic diagram of the structure of the driving component 9 in this application.

[0035] The drive assembly 9 is disposed inside the third compartment 3. The drive gear 91 of the drive assembly 9 is connected to the transmission gear 92, and the transmission gear 92 meshes with the second cylindrical gear 84.

[0036] The first compartment 1 and the second compartment 2, as well as the third compartment 3 and the fourth compartment 4, are connected by a passive joint 7, such that the joint angle between the first compartment 1 and the second compartment 2, as well as the third compartment 3 and the fourth compartment 4, is equal to the joint angle between the second compartment 2 and the third compartment 3.

[0037] In this embodiment, the drive assembly 9 is fixed inside the third chamber 3. By activating the drive assembly 9, the drive gear 91 rotates, causing the transmission gear 92 to rotate simultaneously. Since the transmission gear 92 meshes with the second cylindrical gear 84, the second cylindrical gear 84 drives the transmission cylinder 82 to rotate. Under the rotation of the transmission cylinder 82, the second chamber 2 rotates. Because the rubber spring 85 is connected to the second cylindrical gear 84, the second chamber 2, and the third chamber 3, the rotation of the second cylindrical gear 84 causes the third chamber 3 to rotate under the drive of the rubber spring 85, changing the angle between the second chamber 2 and the third chamber 3, causing them to move closer or further apart, thereby changing the shape of the pipe inspection robot to adapt to pipes of different diameters.

[0038] like Figure 4 The image shown is a cross-sectional view of the passive joint 7 in this application (along...). Figure 2 (Cross-section view along the BB direction).

[0039] The passive joint 7 includes: A power shaft 71 is connected to an omnidirectional wheel 5 located between the first compartment 1 and the second compartment 2, as well as between the third compartment 3 and the fourth compartment 4. A power gear 72 is mounted on the power shaft 71 and is connected to a second motor 73, which is located within the second compartment 2 and the third compartment 3.

[0040] The passive joint 7 also includes: A torsion spring 74 is located between the first compartment 1 and the second compartment 2, with one end connected to the first compartment 1 and the other end connected to the second compartment 2; a torsion spring 74 is located between the third compartment 3 and the fourth compartment 4, with one end connected to the third compartment 3 and the other end connected to the fourth compartment 4; the torsion spring 74 located between the first compartment 1 and the second compartment 2 has the same torque as the torsion spring 74 located between the third compartment 3 and the fourth compartment 4.

[0041] When the omnidirectional wheel 5 and the hemispherical wheel 6 are located in the same axial direction, the joint angles between the first compartment 1 and the second compartment 2, the second compartment 2 and the third compartment 3, and the third compartment 3 and the fourth compartment 4 are equal.

[0042] In this embodiment, the pipe inspection robot in this application only allows for joint angle adjustment between the second compartment 2 and the third compartment 3 via the drive assembly 9. The angles between the first compartment 1 and the second compartment 2, as well as between the third compartment 3 and the fourth compartment 4, are equal. Therefore, when the omnidirectional wheel 5 and the hemispherical wheel 6 are located in the same axial direction, the angles between the first compartment 1 and the second compartment 2, as well as between the third compartment 3 and the fourth compartment 4, will also be adjusted, making the joint angles between the first compartment 1 and the second compartment 2, the second compartment 2 and the third compartment 3, and the third compartment 3 and the fourth compartment 4 equal.

[0043] In this embodiment, the torsion spring 74 allows the omnidirectional wheels 5 and hemispherical wheels 6 to be closer to the inner wall of the pipe under test. Specifically, when the joint angle between the second chamber 2 and the third chamber 3 increases, the torsion spring 74 between the first chamber 1 and the second chamber 2, and between the third chamber 3 and the fourth chamber 4, will be in a stretched state. Under the action of the elastic potential energy of the torsion spring 74, the first chamber 1 and the second chamber 2, and between the third chamber 3 and the fourth chamber 4, will move closer to each other, thereby making the omnidirectional wheels 5 and hemispherical wheels 6 closer to the inner wall of the pipe under test.

[0044] Specifically, when the joint angle between the second compartment 2 and the third compartment 3 decreases, the torsion spring 74 between the first compartment 1 and the second compartment 2, and between the third compartment 3 and the fourth compartment 4 will be in a compressed state. Under the action of the elastic potential energy of the torsion spring 74, the first compartment 1 and the second compartment 2, and between the third compartment 3 and the fourth compartment 4 will move away from each other, thereby making each of the omnidirectional wheels 5 and the hemispherical wheels 6 closer to the inner wall of the pipe to be tested.

[0045] This application proposes a multi-link active-passive articulated pipe inspection robot, aiming to enhance traction, improve adaptability, optimize load estimation methods, and improve motion flexibility. By applying active joints 8, the pipe inspection robot in this application can effectively resist pipe walls, thereby generating greater traction for transporting heavy inspection equipment or long power and communication cables. Through precise torque measurement, the robot can better cope with various loads and environmental changes within the pipe. The use of rubber springs reduces joint size and increases stiffness, resulting in a more compact structure and improved joint torque characteristics. This enhances the robot's adaptability.

[0046] The multi-link active and passive articulated pipeline inspection robot further includes: A third motor 61 is disposed within the first compartment 1 and the fourth compartment 4 on the side near the hemispherical wheel 6, and the power end of the third motor 61 is connected to the hemispherical wheel 6; the third motor 61 is used to drive the hemispherical wheel 6 to rotate along the rolling axis. Figure 6 The diagram shown is an exploded view of the cabin. The main body of the cabin is a frame, used to mount the third motor 61, motor speed controller, and controller. The top and bottom surfaces of the cabin are equipped with covers for sealing and structural limiting. A fork is installed at one end to connect the output shaft of the third motor 61 to the hemispherical wheel 6, providing steering drive force. A groove is formed at the other end of the cabin for mounting a slewing bearing, and a hole is also provided at the end of the cabin for mounting a torsion spring and fixing its support arm. The tumbling axis is oriented with respect to the forward and backward direction of the pipeline inspection robot.

[0047] It is worth noting that in this application, only the omnidirectional wheel 5 between the first compartment 1 and the second compartment 2, and between the third compartment 3 and the fourth compartment 4, is actively rotated by the second motor 73, while the omnidirectional wheel 5 between the second compartment 2 and the third compartment 3 and the hemispherical wheel 6 are passively rotated along the axial direction of the pipe. When the pipe to be tested is straight, both the hemispherical wheel 6 and the omnidirectional wheel 5 rotate about the axial direction of the pipe to be tested, that is, the pipe inspection robot moves forward about the axial direction of the pipe to be tested.

[0048] The multi-link active and passive articulated pipeline inspection robot further includes: An image acquisition device 10 and a controller are provided, the controller being connected to the image acquisition device 10 and the third motor 61. The image acquisition device 10 is located outside the first chamber 1 and is used to acquire images of the pipe under test. The controller is configured to: Based on the image, the direction of the pipeline is identified using the histogram method to obtain pipeline direction information. The third motor 61 is used to drive the hemispherical wheel 6 to rotate along the rolling axis so that the axis of the pipeline to be tested is located within the gap between the hemispherical wheels 6.

[0049] For example, the controller carries a remote control receiver to receive control signals transmitted by the remote control, enabling the robot to walk along the pipe to be tested, and to adjust the robot's posture from a straight line to an "M" shape, so that the omnidirectional wheels can generate driving torque on the pipe wall.

[0050] Specifically, when the pipe to be tested is a bend or a T-shaped pipe, the image acquisition device 10 can acquire an image of the pipe inspection robot when it is in the bend or T-shaped pipe. The operator can remotely control the hemispherical wheel 6 to rotate along the rolling axis through the controller, so that the axis of the pipe to be tested is located in the gap between the hemispherical wheels 6, thereby realizing the turning function of the pipe inspection robot and enabling the pipe inspection robot provided in this application to adapt to pipes of any shape.

[0051] For example, robot impedance control establishes the relationship between the robot's end effector displacement and contact force by equating the force and position control of the robot's end effector to a "spring-mass-damping" model. This control method can adjust the robot's end effector position and contact force by adjusting inertia, damping, and stiffness parameters.

[0052] In this embodiment, the controller is connected to the drive component 9, and the controller is further configured to: Obtain the motion parameters of the active joint 8; the motion parameters include: actual displacement, velocity, and angular acceleration.

[0053] The multi-link active and passive articulated pipeline inspection robot further includes: An angle sensor 86 is disposed within the second chamber 2 and connected to the active joint 8 and the controller. The angle sensor 86 is used to acquire the joint angle between the second chamber 2 and the third chamber 3, as well as the drive angle of the power end of the drive assembly 9. Based on the angle between the second chamber 2 and the third chamber 3 and the drive angle, the angle difference is calculated. The torque between the two chambers is obtained by multiplying the angle difference by the elastic coefficient of the rubber spring 85. Specifically, the angle sensor 86 is connected to the driven shaft 81, and the joint angle between the second chamber 2 and the third chamber 3 can be obtained by the rotation angle of the driven shaft 81.

[0054] The controller is further configured to: Based on the angle, the motion parameters of the active joint 8 are calculated; the actual displacement is: ; In the formula, For joint angle; It is represented as the inverse kinematics solution of the robot.

[0055] The speed is: ; In the formula, Represented as a Jacobian matrix; This represents the joint angular velocity.

[0056] The angular acceleration is: .

[0057] In the formula, This is the joint angular acceleration.

[0058] This application employs a force-based impedance control method. The controller consists of an internal force closed-loop control and an external impedance calculation loop. Based on the deviation between the calculated desired state and the actual motion state, the required robot execution reference force is calculated through the outer loop using the desired impedance model parameters (K, B, M). The inner loop tracks the expected reference force for the interaction between the robot and the actual environment. The expected impedance model parameters typically refer to three key parameters used to describe the dynamic characteristics of a robot's end effector interacting with its environment: inertia (M), damping (B), and stiffness (K). These parameters together constitute a second-order mass-spring-damped system, used to define the robot's compliant response to external forces.

[0059] Specifically, based on the motion parameters, the desired reference force of the active joint 8 is calculated using the desired impedance model; the desired reference force is: ; In the formula, , , These are the parameters of the desired impedance model; , , These are the actual displacement, velocity, and angular acceleration of the active joint 8, respectively. , , These are the reference displacement, velocity, and angular acceleration of the active joint 8, respectively.

[0060] Based on the desired reference force, a desired impedance model is obtained; this desired impedance model is used to determine the force provided by the joint; ideally, the force control closed loop provides force to the robot end effector through joint torque. And satisfy The force provided by the joint is: ; In the formula, Z(s) represents the transfer function; x r x represents the robot's reference displacement or target displacement; x represents the robot's actual displacement. The velocity is represented by the first derivative; Acceleration is represented by the second derivative.

[0061] Based on the expected reference force, a joint driving force reference value is determined; the joint driving force reference value is: ; In the formula, Represented as a Ligâcobi matrix, Characterized as the transpose of the force-Jacobi matrix, it is used to map forces / torques in the operation space (Cartesian space) to driving torques in the joint space; desired reference force. The reference value of the joint driving force is obtained by transposing the Leyakubi matrix. .

[0062] Based on the force provided by the joint, the external force measured by the force sensor is mapped onto the joint space to determine the joint driving force mapping value; the joint driving force mapping value is: .

[0063] Based on the joint driving force reference value and the joint driving force mapping value, a joint driving force control value is determined; the joint driving force control value is: Actual contact force / environmental force The joint driving force is mapped to the transpose of the Leyakubi matrix. The joint driving force control value Ultimately, it serves as the driving force control command value for drive component 9.

[0064] It is worth noting that the aforementioned joint driving force reference value and joint driving force mapping value determine the conversion relationship between "how much thrust is required for the omnidirectional wheel 5 and the hemispherical wheel 6 to hit the pipe wall" and "the output torque of the drive assembly 9".

[0065] For example, by Figure 8 As can be seen, by establishing a dynamic model and applying it to the pipeline inspection robot provided in this application, the input is X, which is the controlled object. r This refers to the desired position of the robot (the desired position of the hemispherical or omnidirectional wheel), and the output is the joint angle q. The torque F to be applied to the joint is calculated by multiplying the difference between the desired and actual positions by the impedance coefficient. r F e The actual control force is measured by sensors, and the inner loop of the force control system applies the desired control force F. e With actual control force F r The result of multiplying the difference by the Jacobian matrix is ​​then applied to the pipeline inspection robot.

[0066] This application provides a multi-link active-passive joint type pipe inspection robot. The drive assembly 9 drives the transmission cylinder 82 to rotate, thereby rotating the second chamber 2. Under the action of the rubber spring 85, the third chamber 3 also rotates simultaneously. Since the elastic potential energy and length of the rubber springs 85 installed in the second chamber 2 and the third chamber 3 are the same, the rotation angles between the second chamber 2 and the third chamber 3 are the same. The first chamber 1 and the second chamber 2, as well as the third chamber 3 and the fourth chamber 4, rotate simultaneously under the action of the torsion spring 74, thus enabling the pipe inspection robot to conform to the pipe wall under test. This application establishes a dynamic model so that the drive assembly 9 can output joint drive force control values ​​according to the robot's desired position and actual position, ensuring that the robot conforms more closely to the pipe wall under test. Compared to a design with only passive joints, the robot provided in this application avoids the situation where the elasticity of torsion springs and other elastic components decreases, leading to a reduction in the robot's conformity to the pipe wall under test.

[0067] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A multi-link active and passive articulated pipe inspection robot, characterized in that, include: The first compartment (1), the second compartment (2), the third compartment (3), and the fourth compartment (4) are hinged together in sequence. The first compartment (1) and the second compartment (2), as well as the third compartment (3) and the fourth compartment (4), are hinged together by a passive joint (7); the second compartment (2) and the third compartment (3) are hinged together by an active joint (8). Drive assembly (9), which is disposed in the third compartment (3) and connected to the active joint (8); The controller, connected to the drive component (9), is further configured to: Obtain the motion parameters of the active joint (8); the motion parameters include: actual displacement, velocity, and angular acceleration; Based on the motion parameters, the expected reference force of the active joint (8) is calculated; Based on the desired reference force, determine the joint driving force control value; Based on the joint driving force control value, the active joint (8) is driven by the driving component (9) to change the angle between the second chamber (2) and the third chamber (3), so that the pipeline inspection robot fits against the inner wall of the pipeline to be tested.

2. The multi-link active-passive articulated pipeline inspection robot according to claim 1, characterized in that, The first compartment (1), the second compartment (2), the third compartment (3), and the fourth compartment (4) are interconnected in an M-shape; omnidirectional wheels (5) are provided at the hinges between the first compartment (1) and the second compartment (2), the second compartment (2) and the third compartment (3), and the third compartment (3) and the fourth compartment (4); the omnidirectional wheels (5) are arranged opposite to each other on both sides of the second compartment (2) and the third compartment (3); hemispherical wheels (6) are provided on the side of the first compartment (1) away from the second compartment (2) and on the side of the fourth compartment (4) away from the third compartment (3); The drive assembly (9) is used to drive the active joint (8) to change the angle between the second chamber (2) and the third chamber (3), so that the omnidirectional wheel (5) fits against the inner wall of the pipe to be tested; the first chamber (1) and the second chamber (2) and the third chamber (3) and the fourth chamber (4) are connected by a passive joint (7), so that the joint angle between the first chamber (1) and the second chamber (2) and the third chamber (3) and the fourth chamber (4) is equal to the joint angle between the second chamber (2) and the third chamber (3).

3. The multi-link active and passive articulated pipeline inspection robot according to claim 2, characterized in that, The active joint (8) includes: Driven shaft (81), on which a transmission cylinder (82), a first cylindrical gear (83), and a second cylindrical gear (84) are mounted; the transmission cylinder (82) meshes with the second cylindrical gear (84), and the transmission cylinder (82) is connected to the second compartment (2); the first cylindrical gear (83) is connected to the third compartment (3); the second cylindrical gear (84) meshes with a transmission gear (92), and the transmission gear (92) meshes with the drive gear (91) of the drive assembly (9); The drive assembly (9) is activated to drive the second cylindrical gear (84) to rotate using the drive gear (91); the rotation of the second cylindrical gear (84) drives the transmission cylinder (82) to rotate, thereby driving the second cabin (2) to rotate.

4. The multi-link active and passive articulated pipe inspection robot according to claim 3, characterized in that, The active joint (8) also includes: A rubber spring (85) is located between the second compartment (2) and the third compartment (3); the rubber spring (85) is disposed opposite to each other on both sides of the second cylindrical gear (84), one end of the rubber spring (85) located on one side of the second cylindrical gear (84) is connected to the second cylindrical gear (84), and the other end is connected to the second compartment (2); one end of the rubber spring (85) located on the other side of the second cylindrical gear (84) is connected to the second cylindrical gear (84), and the other end is connected to the third compartment (3); When the second cylindrical gear (84) rotates, the third compartment (3) rotates simultaneously via the rubber spring (85).

5. A multi-link active and passive articulated pipe inspection robot according to claim 3, characterized in that, The passive joint (7) includes: A power shaft (71) is connected to an omnidirectional wheel (5) located between the first compartment (1) and the second compartment (2), as well as the third compartment (3) and the fourth compartment (4); a power gear (72) is fitted on the power shaft (71), and the power gear (72) is connected to a second motor (73), which is located inside the second compartment (2) and the third compartment (3).

6. The multi-link active-passive articulated pipeline inspection robot according to claim 5, characterized in that, The passive joint (7) also includes: A torsion spring (74) is located between the first compartment (1) and the second compartment (2), with one end connected to the first compartment (1) and the other end connected to the second compartment (2); a torsion spring (74) is located between the third compartment (3) and the fourth compartment (4), with one end connected to the third compartment (3) and the other end connected to the fourth compartment (4); the torsion spring located between the first compartment (1) and the second compartment (2) has the same torque as the torsion spring (74) located between the third compartment (3) and the fourth compartment (4); When the omnidirectional wheel (5) and the hemispherical wheel (6) are located in the same axial direction, the joint angles between the first compartment (1) and the second compartment (2), the second compartment (2) and the third compartment (3), and the third compartment (3) and the fourth compartment (4) are equal.

7. A multi-link active-passive articulated pipeline inspection robot according to claim 6, characterized in that, Also includes: The third motor (61) is located in the first cabin (1) and the fourth cabin (4) on the side near the hemispherical wheel (6), and the power end of the third motor (61) is connected to the hemispherical wheel (6); the third motor (61) is used to drive the pipeline inspection robot to rotate along the tumbling axis.

8. A multi-link active-passive articulated pipeline inspection robot according to claim 7, characterized in that, Also includes: An image acquisition device (10) and a controller are provided. The controller is connected to the image acquisition device (10) and the third motor (61). The image acquisition device (10) is located outside the first chamber (1). The image acquisition device (10) is used to acquire images inside the pipe to be tested. The controller is configured to: Based on the image, the direction of the pipeline is identified using the histogram method to obtain pipeline direction information, and the third motor (61) drives the hemispherical wheel (6) to rotate along the rolling axis so that the axis of the pipeline to be tested is located in the gap between the hemispherical wheels (6).

9. A multi-link active-passive articulated pipeline inspection robot according to claim 1, characterized in that, Also includes: An angle sensor (86) is disposed within the second cabin (2), and is connected to the active joint (8) and the controller. The angle sensor (86) is used to acquire the joint angle between the second cabin (2) and the third cabin (3). The controller is further configured to: Based on the angle, the motion parameters of the active joint (8) are calculated; the actual displacement is: ； In the formula, For joint angle; Represented as the inverse kinematics solution of the robot; The speed is: ； In the formula, Represented as a Jacobian matrix; Joint angular velocity; The angular acceleration is: ； In the formula, This is the joint angular acceleration.

10. A multi-link active-passive articulated pipeline inspection robot according to claim 1, characterized in that, The expected reference force is: ； In the formula, , , These are the parameters of the desired impedance model; , , These are the actual displacement, velocity, and angular acceleration of the active joint (8), respectively. , , These are the reference displacement, velocity, and angular acceleration of the active joint (8), respectively. The controller is further configured to: Based on the desired reference force, a desired impedance model is obtained; the desired impedance model is used to determine the force provided by the joint; the force provided by the joint is: ； In the formula, The velocity is represented by the first derivative; Acceleration represented as the second derivative; Based on the expected reference force, determine the reference value of the joint driving force; Based on the force provided by the joint, determine the joint driving force mapping value; Based on the joint driving force reference value and the joint driving force mapping value, the joint driving force control value is determined.

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