Wheeled wall-climbing robot for high-curvature pipe surfaces and its motion control method

Abstract

The present invention relates to a wall-climbing robot, and in particular to a wheeled wall-climbing robot for use on high-curvature pipe surfaces. The robot comprises a robot control system, a detection and sensing system, a passive compliance system, a robot frame, and a drive system, wherein the passive compliance system and the robot control system are arranged at the front and rear ends of the robot frame; the drive system comprises left and right front wheel drive devices and left and right rear wheel drive devices, wherein the left and right front wheel drive devices are arranged below the passive compliance system, and the left and right rear wheel drive devices are arranged below the rear end of the robot frame; the detection and sensing system is installed on the passive compliance system and the robot frame, and is used to detect the posture information of the robot frame and the roll and yaw information of the passive compliance system and feed it back to the robot control system to perform speed control on the drive system. The present invention can adapt to crawling on high-curvature surfaces, complete the precise control of the robot's movement, and improve the reliability of the wall-climbing robot.

Description

Technical Field

[0001] The present invention relates to a wall-climbing robot, in particular to a wheeled wall-climbing robot facing a high-curvature pipe diameter surface and a motion control method thereof. Background Art

[0002] During energy transportation, factors such as aging, corrosion, and fractures can directly impact the normal operation of pipelines. Because pipelines are often installed overhead, underground, or underwater, they are difficult for personnel to access. Furthermore, the limited interior space and the presence of oil and gas make maintenance difficult and time-consuming. With the advancement of science and technology, robotic operations are emerging as an advanced technology to replace humans in dangerous and complex operations in extreme environments. Based on the characteristics of pipeline environments and operational requirements, currently developed pipeline operation robots can be broadly categorized as support-type and wall-climbing-type. The former utilizes a multi-claw structure to support the pipeline's inner wall, allowing for rapid movement along the pipeline. However, its disadvantage is that the robot must occupy the entire cross-section of the pipeline during operation, making it difficult to navigate around bends, junctions like tees, or partial blockages. Wall-climbing-type structures adhere to the pipeline's inner wall using magnetic attraction. Due to their flexible steering and obstacle-crossing capabilities, the robot has excellent motion adaptability. However, the interior of the pipeline is a highly curved surface, and the four-wheel environment changes in real time during robot movement. This requires an accurate kinematic model for robot movement and steering, making current motion control methods incapable of achieving precise control of the robot's motion. Summary of the Invention

[0003] The present invention aims at high-curvature walls of pipelines and proposes a wheeled wall-climbing robot capable of adapting to high-curvature surfaces and a motion control method thereof. The passively compliant magnetic adsorption wheeled wall-climbing robot provided by the present invention can improve the magnetic adsorption force and motion stability of the wall-climbing robot through the action of passive joints. At the same time, according to the posture changes of the robot in the pipeline curved surface environment, a motion control method of the wheeled wall-climbing robot on the pipeline curved surface is proposed to achieve precise control of the robot's motion and improve the reliability of the wall-climbing robot. The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a wheeled wall-climbing robot for high-curvature pipe diameter surfaces, comprising a robot control system, a detection and sensing system, a passive compliance system, a robot frame and a drive system, wherein the passive compliance system and the robot control system are respectively arranged at the front and rear ends of the robot frame, and the passive compliance system has the degrees of freedom of roll and yaw;

[0004] The drive system includes a right front wheel drive device, a left front wheel drive device, a right rear wheel drive device and a left rear wheel drive device, wherein the right front wheel drive device and the left front wheel drive device are both arranged below the passive compliance system, and the right rear wheel drive device and the left rear wheel drive device are both arranged below the rear end of the robot frame;

[0005] The detection and perception system is installed on the passive compliance system and the robot frame. The detection and perception system is used to detect the posture information of the robot frame and the roll and yaw information of the passive compliance system and feed it back to the robot control system. The robot control system controls the speed of the drive system.

[0006] The passive compliance system includes a reset spring, a yaw axis, a roll axis, a mounting base and an upper connecting flange, wherein the roll axis is rotatably mounted on the mounting base, one end of the yaw axis is vertically connected to the roll axis, and the other end of the yaw axis is rotatably connected to the upper connecting flange. The upper connecting flange is connected to the mounting base through two reset springs symmetrically arranged on both sides of the roll axis, and the upper connecting flange is connected to the robot frame.

[0007] The detection and perception system includes a tilt sensor unit and two angle sensor units, wherein the tilt sensor unit is arranged at the center of the robot frame for feedback of the angle between the robot and the pipeline busbar; the two angle sensor units are respectively arranged on the yaw axis and the roll axis for feedback of the angle parameters of relative rotation around the central axis of the yaw axis and the roll axis and provide them to the robot control system.

[0008] The tilt sensing unit includes a gyroscope and an accelerometer.

[0009] A front drive device mounting seat is provided below the passive compliance system, and the right front wheel drive device and the left front wheel drive device are symmetrically arranged on the front drive device mounting seat;

[0010] A rear drive device mounting seat is provided at the rear end of the robot frame, and the right rear wheel drive device and the left rear wheel drive device are symmetrically arranged on the rear drive device mounting seat.

[0011] The right front wheel drive device, the left front wheel drive device, the right rear wheel drive device and the left rear wheel drive device have the same structure, and all include a brushless DC motor, a multi-stage gear transmission mechanism and an adsorption magnetic wheel, wherein the output end of the brushless DC motor is connected to the adsorption magnetic wheel through the multi-stage gear transmission mechanism, and the adsorption magnetic wheel is rotatably mounted on the lower end of the front drive device mounting seat or the rear drive device mounting seat.

[0012] The front drive device mounting seat and the rear drive device mounting seat have the same structure, both including a motor accommodating chamber located at the upper part and a gear box arranged at both ends of the motor accommodating chamber. The brushless DC motor is accommodated in the motor accommodating chamber, and the multi-stage gear transmission mechanism is accommodated in the gear box.

[0013] The multi-stage gear transmission mechanism includes gear A, gear B and gear C that are meshed and transmitted in sequence from top to bottom, wherein gear A is arranged on the output shaft of the brushless DC motor, gear B is rotatably mounted on the front drive device mounting seat or the rear drive device mounting seat, and gear C is arranged on the magnetic wheel support shaft of the adsorption magnetic wheel.

[0014] A motion control method for a wheeled wall-climbing robot facing a high-curvature pipe diameter surface is characterized by comprising the following steps:

[0015] 1) Construct the pipeline global coordinate system {W} and the robot center of mass coordinate system {M} of the pipeline where the wall-climbing robot is located;

[0016] 2) Determine the position of the wall-climbing robot in the pipeline by the relative changes of the pipeline global coordinate system {W} and the robot center of mass coordinate system {M};

[0017] 3) Based on the position of the passive compliance system of the wall-climbing robot and the point contact positions of the multiple adsorption magnetic wheels with the pipe wall, a coordinate system of the wall-climbing robot body and a contact coordinate system of the multiple adsorption magnetic wheels with the pipe wall are established;

[0018] 4) Based on the transformation relationship between the coordinate systems of the wall-climbing robot body, the kinematic model of the wall-climbing robot in the pipe curved surface environment is obtained;

[0019] 5) According to the kinematic model, the posture change rate of the robot body in the reference coordinate system is obtained, and the driving speed of each adsorption magnetic wheel of the wall-climbing robot is determined according to the posture change rate. Then the motion control of the wall-climbing robot is realized.

[0020] The step 1) is specifically as follows:

[0021] The center point of the pipe cross section is taken as the origin, the pipe axis is the z-axis, the vertical upward direction is the x-axis, and the y-axis is perpendicular to the x-axis and z-axis to complete the establishment of the pipe global coordinate system {W};

[0022] The robot's center of mass is taken as the origin, the robot's forward direction is the z-axis direction, the x-axis is perpendicular to the top plane of the robot, and the y-axis is perpendicular to the x- and z-axes to complete the establishment of the robot's center of mass coordinate system {M}.

[0023] The step 2) is specifically as follows:

[0024] Assume that at the instantaneous time t+t, the coordinate transformation pose vector of the robot's center of mass coordinate system {M} is u=[xyz φ x φ y φ z ] T , then:

[0025]

[0026]

[0027] Among them, (x, y, z) and (φ x ,φ y ,φ z ) represent the displacement of the robot's center of mass coordinate system {M} and the angle of rotation around the x, y, and z axes, respectively. and They are the robot mass center coordinate system {M} and the instantaneous coincidence coordinate system of the robot mass center The velocity and angular velocity components in .

[0028] The step 3) is specifically as follows:

[0029] Assuming that the adsorption magnetic wheel is simplified to a rigid disk and the contact between the adsorption magnetic wheel and the pipe wall is point contact, the Sheth-Uicker method is used to establish the body coordinate system of the wall-climbing robot and the contact coordinate systems of multiple adsorption magnetic wheels and the pipe wall. Then, we have:

[0030] The body coordinate system of the wall-climbing robot includes: the robot mass center coordinate system {M}, the yaw coordinate system {F1}, the roll coordinate system {F2} and the wheel center coordinate system {O i (i=1, 2, 3, 4)};

[0031] The yaw coordinate system {F1} is established on the yaw axis of the passive compliance system, with its zF1 axis coinciding with the yaw axis and its xF1 axis being parallel to the roll axis;

[0032] The roll coordinate system {F2} is established on the roll axis of the passive compliance system, with its zF2 axis coinciding with the roll axis and its yF2 axis being parallel to the left and right front magnetic wheel support axes;

[0033] The wheel center coordinate system {O i (i=1,2,3,4)} coincides with the center of the adsorption magnetic wheel, yO i The axis coincides with the magnetic wheel support axis, zO i The axis points to the forward direction of the adsorption magnetic wheel; where i is the serial number of the corresponding adsorption magnetic wheel;

[0034] The contact coordinate system between the multiple adsorption magnetic wheels and the pipe wall is:

[0035] Wheel wall contact coordinate system {P i (i=1,2,3,4)} coincides with the contact point of the wheel wall, yP i The axis points to the center of the magnetic wheel, zP i Pointing to the tangent direction of the wheel wall; where i is the serial number of the corresponding magnetic wheel;

[0036] Instantaneous coincidence coordinate system of robot's center of mass The instantaneous coincidence with the robot's center of mass coordinate system {M} at time t; the instantaneous coincidence coordinate system when the wheel wall contacts Contact coordinate system with wheel wall {P i} coincide at the instant of time t.

[0037] The steps 4) to 5) are specifically as follows:

[0038] According to the robot body structure and pipeline structure characteristics, the wheel wall contact coordinate system {P i (i=1,2,3,4)} relative wheel wall contact instantaneous coincidence coordinate system The derivative of the homogeneous change matrix at time t for:

[0039]

[0040] Wherein, R' represents the relative curvature radius, r represents the radius of the adsorption magnetic wheel (523), represents the angular velocity of the adsorption magnetic wheel (523), represents the rate of change of the geometric contact angle between the adsorption magnetic wheel (523) and the wall surface, and the coordinate transformation matrix of the body coordinate system of the wall-climbing robot is obtained by the relevant structural dimensions of the robot and the yaw angle and roll angle of the passive compliance system (3);

[0041] The instantaneous coincidence coordinate system of the robot mass center coordinate system {M} relative to the robot mass center at time t is obtained by the transformation relationship between the body coordinate system of the wall climbing robot and the contact coordinate system of the plurality of adsorption magnetic wheels (523) and the pipe wall. The relationship is:

[0042]

[0043] After taking the derivative on both sides of the equation, we can get the following equation based on the principles of matrix inverse operation and differential operation:

[0044]

[0045] Among them, θ fi (i=1,2) are yaw angle and roll angle respectively, D i (i=1, 2, 3, 4) are the 6×4 Jacobian matrices of the four magnetic wheels respectively. Combining formula (5), we can obtain the kinematic model of the wall-climbing robot in the pipe curved surface environment:

[0046]

[0047] in, It includes the driving velocity vector of the driving adsorption magnetic wheel i, the rate of change of the rotation angle of the passive compliance system (3) and the rate of change of the wheel wall geometric contact angle; the rotation angle θ of the passive compliance system (3) f1 and θ f2 The wheel wall geometric contact angle δ is obtained by the detection and perception system (2). i Obtained through the geometric constraint relationship between the robot mechanism and the wall; D i The matrix is ​​the Jacobian matrix of the adsorption magnetic wheel i, which is a known matrix; The matrix is ​​the rate of change of posture, including the change of the robot's center of mass and the three angle rotation changes; that is: middle Three position changes and Three angle changes;

[0048] Determining the driving speed of each adsorption magnetic wheel (523) of the wall-climbing robot according to the posture change rate Right now:

[0049] The obtained value in formula (6) Substitute into formula (5) to obtain the rotation speed of the four magnetic wheels of the robot

[0050] The present invention has the following beneficial effects and advantages:

[0051] 1. The present invention provides a wheeled wall-climbing robot for high-curvature pipe diameter surfaces. It adopts a multi-stage gear transmission mechanism, which can raise the height of the robot body to avoid interference with the pipe wall during movement, and at the same time can increase the driving force of the magnetic wheel.

[0052] 2. This invention utilizes a passive compliance mechanism. The roll motion of the passive compliance system passively adjusts the left and right heights of the left front and right rear wheel drive units, thereby maintaining simultaneous adhesion of all four magnetic wheels to the curved surface. This improves the robot's adhesion stability and surface adaptability. The yaw motion of the passive compliance system is actively achieved by the speed difference between the magnetic wheels of the left front and right rear wheel drive units. Compared to the sliding steering method of traditional wheeled wall-climbing robots, the axis-to-articulation steering of the passive compliance joint reduces forced slippage of the magnetic wheels during steering, thereby enhancing the robot's steering flexibility.

[0053] 3. The present invention is designed to meet the needs of high-curvature pipeline wall inspection and maintenance. It can be equipped with operating tools to replace manual work in wall inspection and maintenance, which not only reduces labor intensity and improves work efficiency, but also reduces risks and ensures personal safety.

[0054] 4. The present invention provides a motion control method for a wheeled wall-climbing robot for high-curvature pipe diameter surfaces. Based on the surface kinematic model, the control system can reasonably distribute speeds to the four magnetic wheels in response to the high-curvature wall characteristics of the pipeline, effectively avoiding the motor speed mismatch phenomenon that occurs when the wall-climbing robot walks on the curved surface of the pipeline, which is conducive to the precise control of the robot's motion on the curved surface of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a structural schematic diagram of a wheeled wall-climbing robot for facing a high-curvature pipe diameter surface according to the present invention;

[0056] Figure 2 Schematic diagram of the passive compliance system and the drive system in the present invention;

[0057] Among them: 1 is the robot control system, 2 is the detection and perception system, 21 is the tilt sensor unit, 22 is the angle sensor unit, 3 is the passive compliance system, 301 is the return spring, 302 is the yaw axis, 303 is the roll axis, 304 is the mounting base, 4 is the robot frame, 5 is the drive system, 51 is the right front wheel drive device, 52 is the left front wheel drive device, 53 is the right rear wheel drive device, 54 is the left rear wheel drive device, 521 is the brushless DC Motor, 522 is a multi-stage gear transmission mechanism, 523 is an adsorption magnetic wheel, 5221 is a sealed bearing seat, 5222 is a shaft sleeve, 5223 is gear A, 5224 is gear B, 5225 is bearing A, 5226 is a support shaft, 5227 is a bearing seat, 5228 is a shaft retaining ring, 5229 is bearing B, 52210 is gear C, 52211 is a deep groove ball bearing, 52212 is a magnetic wheel support shaft, and 52213 is a shaft shoulder retaining ring;

[0058] Figure 3 Schematic diagram of the coordinate system of the robot body of the present invention;

[0059] Figure 4 Schematic diagram of the wheel wall contact coordinate system of the present invention;

[0060] Figure 5 Schematic diagram of coordinate transformation relationship of the coordinate system of the wall-climbing robot of the present invention. DETAILED DESCRIPTION

[0061] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0062] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, the specific implementation methods of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the invention. Therefore, the present invention is not limited to the specific implementation methods disclosed below.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art of the art to which the present invention pertains. The terms used in the specification of the invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention.

[0064] The present invention will be further described below in conjunction with the accompanying drawings.

[0065] like Figure 1 As shown, the present invention provides a wheeled wall-climbing robot for high-curvature pipe surfaces, including a robot control system 1, a detection and perception system 2, a passive compliance system 3, a robot frame 4 and a drive system 5, wherein the passive compliance system 3 and the robot control system 1 are respectively arranged at the front and rear ends of the robot frame 4, and the passive compliance system 3 has the degrees of freedom of roll and yaw; the drive system 5 includes a right front wheel drive device 51, a left front wheel drive device 52, a right rear wheel drive device 53 and a left rear wheel drive device 54, wherein the right front wheel drive device 51 and the left front wheel drive device 52 are both arranged below the passive compliance system 3, and the right rear wheel drive device 53 and the left rear wheel drive device 54 are both arranged below the rear end of the robot frame 4; the detection and perception system 2 is installed on the passive compliance system 3 and the robot frame 4, and the detection and perception system 2 is used to detect the posture information of the robot frame 4 and the roll and yaw information of the passive compliance system 3 and feed back to the robot control system 1, and the robot control system 1 controls the speed of the drive system 5 to drive the robot as a whole to move accurately.

[0066] like Figure 2 As shown, in an embodiment of the present invention, the passive compliance system 3 includes a reset spring 301, a yaw axis 302, a roll axis 303, a mounting base 304 and an upper connecting flange, wherein the roll axis 303 is rotatably mounted on the mounting base 304, one end of the yaw axis 302 is vertically connected to the roll axis 303, and the other end of the yaw axis 302 is rotatably connected to the upper connecting flange, the upper connecting flange is connected to the mounting base 304 through two reset springs 301 symmetrically arranged on both sides of the roll axis 303, and the upper connecting flange is connected to the robot frame 4.

[0067] In an embodiment of the present invention, the detection and perception system 2 includes a tilt sensor unit 21 and two angle sensor units 22, wherein the tilt sensor unit 21 is arranged at the center of the robot frame 4, and is used to feedback the angle between the robot and the pipeline busbar; the two angle sensor units 22 are respectively arranged on the yaw axis 302 and the roll axis 303, and are used to feedback the angle parameters of the relative rotation around the central axis of the yaw axis 302 and the roll axis 303 and provide them to the robot control system 1.

[0068] In an embodiment of the present invention, the inclination sensing unit 21 includes a gyroscope and an accelerometer, which is used to feed back the angle between the robot and the pipeline busbar.

[0069] Furthermore, a front drive device mounting seat is provided below the passive compliance system 3, and the right front wheel drive device 51 and the left front wheel drive device 52 are symmetrically arranged on the front drive device mounting seat; a rear end of the robot frame 4 is provided with a rear drive device mounting seat, and the right rear wheel drive device 53 and the left rear wheel drive device 54 are symmetrically arranged on the rear drive device mounting seat.

[0070] like Figure 2 As shown, in the embodiment of the present invention, the right front wheel drive device 51, the left front wheel drive device 52, the right rear wheel drive device 53 and the left rear wheel drive device 54 have the same structure, and all include a brushless DC motor 521, a multi-stage gear transmission mechanism 522 and an adsorption magnetic wheel 523, wherein the output end of the brushless DC motor 521 is connected to the adsorption magnetic wheel 523 through the multi-stage gear transmission mechanism 522, and the adsorption magnetic wheel 523 is rotatably mounted on the lower end of the front drive device mounting seat or the rear drive device mounting seat.

[0071] In an embodiment of the present invention, the multi-stage gear transmission mechanism 522 includes gear A5223, gear B5224 and gear C52210 that are meshed and transmitted in sequence from top to bottom, wherein gear A5223 is arranged on the output shaft of the brushless DC motor 521, gear B5224 is rotatably mounted on the front drive device mounting seat or the rear drive device mounting seat, and gear C52210 is arranged on the magnetic wheel support shaft 52212 of the adsorption magnetic wheel 523.

[0072] Specifically, sealed bearing seats 5221 and bearing seats 5227 are located below the front and rear drive mounting blocks on either side. Gear A 5223 is mounted on the sealed bearing seats 5221 via a sleeve 5222. Bearing seats 5227 are provided with a support shaft 5226, to which gear B 5224 is mounted via bearing A 5225. The magnetic wheel support shaft 52212 is mounted on the front and rear drive mounting blocks via deep groove ball bearings 52211 and axially restrained by a shoulder retaining ring 52213. Bearing B 5229 is located at the end of the magnetic wheel support shaft 52212. The multi-stage gear transmission mechanism 522 increases the robot's height, preventing interference with the pipe wall during movement, while also increasing the driving force of the magnetic wheel.

[0073] Specifically, the front drive device mounting seat and the rear drive device mounting seat have the same structure, both including a motor accommodating chamber located at the upper part and a gear box arranged at both ends of the motor accommodating chamber, the brushless DC motor 521 is accommodated in the motor accommodating chamber, and the multi-stage gear transmission mechanism 522 is accommodated in the gear box.

[0074] In an embodiment of the present invention, the robot control system 1 is installed on the electrical box of the robot frame, the detection and sensing system 2 is installed on the passive compliance system 3 and the robot frame 4, the detection and sensing system 2 feeds back relevant transmission signals to the robot control system 1, and the robot control system 1 controls the speed of the four adsorption magnetic wheels 523 of the drive system 5 to drive the robot as a whole to move accurately.

[0075] Specifically, the robot frame 4 is made of aluminum alloy and is provided with a cavity inside, which can be used to install and arrange relevant control system components and can also carry relevant working tools for inspection and maintenance.

[0076] In an embodiment of the present invention, the yaw movement of the yaw axis 302 is actively completed by the speed difference of the magnetic wheels of the left front wheel drive device 52 and the right rear wheel drive device 53, and the roll movement of the roll axis 303 is passively completed by the magnetic adsorption force between the adsorption magnetic wheel 523 and the curved surface. During movement, the height difference between the left front wheel drive device 52 and the right rear wheel drive device 53 can be passively adjusted to keep the four adsorption magnetic wheels 523 adsorbed on the curved surface at all times, and the reset spring 301 can prevent the passive compliance system 3 from being in an over-deflected state.

[0077] The present invention aims at the high-curvature wall surface of the pipeline and proposes a wheeled wall-climbing robot that can adapt to high-curvature surfaces. Through the action of passive joints, the magnetic adsorption force and movement stability of the wall-climbing robot can be improved, while the precise control of the robot's movement can be completed, thereby improving the reliability of the wall-climbing robot.

[0078] This embodiment also discloses a motion control method for a wheeled wall-climbing robot facing a high-curvature pipe diameter surface. Figures 3 to 5 As shown, this method can be applied to the above-mentioned four-wheel magnetic adsorption wall-climbing robot, and specifically includes the following steps:

[0079] 1) Construct the pipeline global coordinate system {W} and the robot center of mass coordinate system {M} of the pipeline where the wall-climbing robot is located;

[0080] 2) Determine the position of the wall-climbing robot in the pipeline by the relative changes of the pipeline global coordinate system {W} and the robot center of mass coordinate system {M};

[0081] 3) establishing a coordinate system of the wall-climbing robot body and a contact coordinate system of the multiple adsorption magnetic wheels 523 and the pipe wall based on the position of the passive compliance system 3 of the wall-climbing robot and the point contact positions of the multiple adsorption magnetic wheels 523 and the pipe wall;

[0082] 4) Based on the transformation relationship between the coordinate systems of the wall-climbing robot body, the kinematic model of the wall-climbing robot in the pipe curved surface environment is obtained;

[0083] 5) According to the kinematic model, the posture change rate of the robot body in the reference coordinate system is obtained, and the driving speed of each adsorption magnetic wheel 523 of the wall-climbing robot is determined according to the posture change rate. Then the motion control of the wall-climbing robot is realized.

[0084] Among them, such as Figure 3 As shown in FIG, constructing the pipeline global coordinate system {W} and the robot center of mass coordinate system {M} of the pipeline where the wall-climbing robot is located includes the following steps:

[0085] The center point of the pipe cross section is taken as the origin, the pipe axis is the z-axis, the vertical upward direction is the x-axis, and the y-axis is perpendicular to the x-axis and z-axis to complete the establishment of the pipe global coordinate system {W};

[0086] The robot's center of mass is taken as the origin, the robot's forward direction is the z-axis direction, the x-axis is perpendicular to the top plane of the robot, and the y-axis is perpendicular to the x- and z-axes to complete the establishment of the robot's center of mass coordinate system {M}.

[0087] The position of the wall-climbing robot in the pipeline is determined by the relative changes of the pipeline global coordinate system {W} and the robot mass center coordinate system {M}; assuming that at the instantaneous time t+t at time t, the coordinate transformation pose vector of the robot mass center coordinate system {M} is u=[xyz φ x φ y φ z ] T , then:

[0088]

[0089]

[0090] Among them, (x, y, z) and (φ x ,φ y ,φ z ) represent the displacement of the robot's center of mass coordinate system {M} and the angles of rotation around the x, y, and z axes, respectively. and They are the robot mass center coordinate system {M} and the instantaneous coincidence coordinate system of the robot mass center The velocity and angular velocity components in .

[0091] According to the position of the passive compliant joint of the wall-climbing robot and the high-pair contact between the magnetic wheel and the pipe wall, the Sheth-Uicker method is used to establish the body coordinate system of the wall-climbing robot and the contact coordinate system between the magnetic wheel and the pipe wall, as shown in the following example: Figure 3 The robot body coordinate system shown and Figure 4 The wheel wall contact coordinate system is shown;

[0092] The robot's body coordinate system includes: the wall-climbing robot's body coordinate system, including: the robot's center of mass coordinate system {M}, the yaw coordinate system {F1}, the roll coordinate system {F2}, and the wheel center coordinate system {O i (i=1, 2, 3, 4)};

[0093] The yaw coordinate system {F1} is established on the yaw axis 302 of the passive compliance system 3 , wherein the zF1 axis thereof coincides with the yaw axis 302 , and the xF1 axis thereof is parallel to the roll axis 303 ;

[0094] The roll coordinate system {F2} is established on the roll axis 303 of the passive compliance system 3, with its zF2 axis coinciding with the roll axis 303 and its yF2 axis parallel to the left and right front magnetic wheel support axes;

[0095] The wheel center coordinate system {O i (i=1, 2, 3, 4)} coincides with the center of the adsorption magnetic wheel 523, yO i The axis coincides with the magnetic wheel support axis, zO i The axis points to the forward direction of the adsorption magnetic wheel 523; wherein i is the serial number of the corresponding adsorption magnetic wheel 523;

[0096] The contact coordinate system between the multiple adsorption magnetic wheels 523 and the pipe wall is:

[0097] Wheel wall contact coordinate system {P i (i=1,2,3,4)} coincides with the contact point of the wheel wall, yP i The axis points to the center of the magnetic wheel, zP i Pointing to the tangent direction of the wheel wall; where i is the serial number of the corresponding magnetic wheel;

[0098] Instantaneous coincidence coordinate system of robot's center of mass The instantaneous coincidence with the robot's center of mass coordinate system {M} at time t; the instantaneous coincidence coordinate system when the wheel wall contacts Contact coordinate system with wheel wall {P i} coincide at the instant of time t.

[0099] In step 4), the kinematic model of the wall-climbing robot in the pipe curved surface environment is obtained according to the transformation relationship between the coordinate systems of the wall-climbing robot body, as follows:

[0100] According to the robot body structure and pipeline structure characteristics, the wheel wall contact coordinate system {P i (i=1,2,3,4)} relative wheel wall contact instantaneous coincidence coordinate system The derivative of the homogeneous change matrix at time t for:

[0101]

[0102] Wherein, R' represents the relative curvature radius, r represents the radius of the adsorption magnetic wheel 523, represents the angular velocity of the adsorption magnetic wheel 523, represents the rate of change of the geometric contact angle between the adsorption magnetic wheel 523 and the wall surface. The coordinate transformation matrix of the body coordinate system of the wall-climbing robot is obtained by the relevant structural dimensions of the robot and the yaw angle and roll angle of the passive compliance system 3;

[0103] like Figure 5 The figure shows the coordinate transformation relationship of the wall-climbing robot coordinate system of the present invention. According to the transformation relationship between the body coordinate system of the wall-climbing robot and the contact coordinate system of the multiple adsorption magnetic wheels 523 and the pipe wall, the instantaneous coincidence coordinate system of the robot's center of mass coordinate system {M} relative to the robot's center of mass at time t is obtained. The relationship is:

[0104]

[0105] After taking the derivative on both sides of the equation, we can get the following equation based on the principles of matrix inverse operation and differential operation:

[0106]

[0107] Among them, θ fi (i=1,2) are yaw angle and roll angle respectively, D i (i=1, 2, 3, 4) are the 6×4 Jacobian matrices of the four magnetic wheels respectively. Combining formula (5), we can obtain the kinematic model of the wall-climbing robot in the pipe curved surface environment:

[0108]

[0109] in, It includes the driving velocity vector of the driving adsorption magnetic wheel i, the rate of change of the rotation angle of the passive compliance system 3 and the rate of change of the wheel wall geometric contact angle; the rotation angle θ of the passive compliance system 3 f1 and θ f2 The wheel wall geometric contact angle δ is obtained by the detection and perception system 2. i Obtained through the geometric constraint relationship between the robot mechanism and the wall; D i The matrix is ​​the Jacobian matrix of the adsorption magnetic wheel i, which is a known matrix; The matrix is ​​the rate of change of posture, including the change of the robot's center of mass and the three angle rotation changes; that is: middle Three position changes and Three angle changes;

[0110] In step 5), the driving speed of each adsorption magnetic wheel 523 of the wall-climbing robot is determined according to the posture change rate. Right now:

[0111] The obtained value in formula (6) Substituting into formula (5), It can also be concluded that Of the three parameters, only the rotation speed of the robot's four magnetic wheels is unknown, namely These four parameters can be calculated according to equation (5), that is, the rotation speed of the four magnetic wheels of the robot

[0112] The present invention provides a motion control method for a wheeled wall-climbing robot for high-curvature pipe diameter surfaces. Based on the surface kinematic model, the control system can reasonably distribute speeds to the four magnetic wheels according to the high-curvature wall characteristics of the pipeline, effectively avoiding the motor speed mismatch phenomenon that occurs when the wall-climbing robot walks on the curved surface of the pipeline, which is conducive to the precise control of the robot's motion on the curved surface of the pipeline.

[0113] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A wheeled wall-climbing robot for high-curvature pipe surfaces, characterized in that: The invention comprises a robot control system (1), a detection and sensing system (2), a passive compliance system (3), a robot frame (4) and a drive system (5), wherein the passive compliance system (3) and the robot control system (1) are respectively arranged at the front and rear ends of the robot frame (4), and the passive compliance system (3) has the degrees of freedom of roll and yaw; The drive system (5) includes a right front wheel drive device (51), a left front wheel drive device (52), a right rear wheel drive device (53) and a left rear wheel drive device (54), wherein the right front wheel drive device (51) and the left front wheel drive device (52) are both arranged below the passive compliance system (3), and the right rear wheel drive device (53) and the left rear wheel drive device (54) are both arranged below the rear end of the robot frame (4); The detection and perception system (2) is installed on the passive compliance system (3) and the robot frame (4). The detection and perception system (2) is used to detect the posture information of the robot frame (4) and the roll and yaw information of the passive compliance system (3) and feed back to the robot control system (1). The robot control system (1) obtains the kinematic model of the wall-climbing robot in the pipe curved surface environment according to the transformation relationship between the coordinate systems of the wall-climbing robot body, and controls the speed of the drive system (5) according to the kinematic model. The detection and perception system (2) comprises: an inclination sensor unit (21) and two angle sensor units (22), wherein the inclination sensor unit (21) is arranged at the center of the robot frame (4) and is used to feedback the angle between the robot and the pipeline busbar; Two angle sensor units (22) are respectively arranged on the yaw axis (302) and the roll axis (303), and are used to feed back angle parameters of relative rotation around the central axes of the yaw axis (302) and the roll axis (303) and provide them to the robot control system (1); The tilt sensing unit (21) includes a gyroscope and an accelerometer.

2. The wheeled wall-climbing robot for high-curvature pipe diameter surfaces according to claim 1, characterized in that: The passive compliance system (3) comprises a return spring (301), a yaw axis (302), a roll axis (303), a mounting base (304) and an upper connecting flange, wherein the roll axis (303) is rotatably mounted on the mounting base (304), one end of the yaw axis (302) is vertically connected to the roll axis (303), and the other end of the yaw axis (302) is rotatably connected to the upper connecting flange, the upper connecting flange is connected to the mounting base (304) via two return springs (301) symmetrically arranged on both sides of the roll axis (303), and the upper connecting flange is connected to the robot frame (4).

3. The wheeled wall-climbing robot for high-curvature pipe surfaces according to claim 1, characterized in that: A front drive device mounting seat is provided below the passive compliance system (3), and the right front wheel drive device (51) and the left front wheel drive device (52) are symmetrically arranged on the front drive device mounting seat; A rear drive device mounting seat is provided at the rear end of the robot frame (4), and the right rear wheel drive device (53) and the left rear wheel drive device (54) are symmetrically arranged on the rear drive device mounting seat.

4. The wheeled wall-climbing robot for high-curvature pipe diameter surfaces according to claim 3, characterized in that: The right front wheel drive device (51), the left front wheel drive device (52), the right rear wheel drive device (53) and the left rear wheel drive device (54) have the same structure and all include a brushless DC motor (521), a multi-stage gear transmission mechanism (522) and an adsorption magnetic wheel (523), wherein the output end of the brushless DC motor (521) is connected to the adsorption magnetic wheel (523) through the multi-stage gear transmission mechanism (522), and the adsorption magnetic wheel (523) is rotatably mounted on the lower end of the front drive device mounting seat or the rear drive device mounting seat; The front drive device mounting seat and the rear drive device mounting seat have the same structure, both comprising a motor accommodating chamber located at the upper portion and a gear box disposed at both ends of the motor accommodating chamber, the brushless DC motor (521) being accommodated in the motor accommodating chamber, and the multi-stage gear transmission mechanism (522) being accommodated in the gear box; The multi-stage gear transmission mechanism (522) comprises a gear A (5223), a gear B (5224) and a gear C (52210) which are meshed and transmitted in sequence from top to bottom, wherein the gear A (5223) is arranged on the output shaft of the brushless DC motor (521), the gear B (5224) is rotatably mounted on the front drive device mounting seat or the rear drive device mounting seat, and the gear C (52210) is arranged on the magnetic wheel support shaft (52212) of the adsorption magnetic wheel (523).

5. The motion control method of a wheeled wall-climbing robot facing a high-curvature pipe diameter surface according to any one of claims 1 to 4, characterized in that: The following steps are involved: 1) Construct the pipeline global coordinate system {W} and the robot center of mass coordinate system {M} of the pipeline where the wall-climbing robot is located; 2) Determine the position of the wall-climbing robot in the pipeline by the relative changes of the pipeline global coordinate system {W} and the robot center of mass coordinate system {M}; 3) establishing a coordinate system of the wall-climbing robot body and a contact coordinate system of the multiple adsorption magnetic wheels (523) and the pipe wall according to the position of the passive compliance system (3) of the wall-climbing robot and the point contact positions of the multiple adsorption magnetic wheels (523) and the pipe wall; 4) Based on the transformation relationship between the coordinate systems of the wall-climbing robot body, the kinematic model of the wall-climbing robot in the pipe curved surface environment is obtained; 5) According to the kinematic model, the rate of change of the robot body's posture in the reference coordinate system is obtained, and the driving speed of each adsorption magnetic wheel (523) of the wall-climbing robot is determined according to the rate of change of the posture Then the motion control of the wall-climbing robot is realized.

6. The motion control method of a wheeled wall-climbing robot facing a high-curvature pipe diameter surface according to claim 5, characterized in that: The step 1) is specifically as follows: The center point of the pipe cross section is taken as the origin, the pipe axis is the z-axis, the vertical upward direction is the x-axis, and the y-axis is perpendicular to the x-axis and z-axis to complete the establishment of the pipe global coordinate system {W}; The robot's center of mass is taken as the origin, the robot's forward direction is the z-axis direction, the x-axis is perpendicular to the top plane of the robot, and the y-axis is perpendicular to the x- and z-axes to complete the establishment of the robot's center of mass coordinate system {M}.

7. The motion control method of a wheeled wall-climbing robot facing a high-curvature pipe diameter surface according to claim 5, characterized in that: The step 2) is specifically as follows: Assume that at the instantaneous time t+Δt, the coordinate transformation pose vector of the robot's center of mass coordinate system {M} is u=[xy z φ x φ y φ z ] T , then: Among them, (x, y, z) and (φ x ,φ y ,φ z ) represent the displacement of the robot's center of mass coordinate system {M} and the angles of rotation around the x, y, and z axes, respectively. and They are the robot mass center coordinate system {M} and the instantaneous coincidence coordinate system of the robot mass center The velocity and angular velocity components in .

8. The motion control method of a wheeled wall-climbing robot facing a high-curvature pipe diameter surface according to claim 5, characterized in that: The step 3) is specifically as follows: Assuming that the adsorption magnetic wheel (523) is simplified to a rigid disk, and the contact between the adsorption magnetic wheel (523) and the pipe wall is point contact, the body coordinate system of the wall-climbing robot and the contact coordinate systems of the multiple adsorption magnetic wheels (523) and the pipe wall are established by the Sheth-Uicker method, then: The body coordinate system of the wall-climbing robot includes: the robot mass center coordinate system {M}, the yaw coordinate system {F1}, the roll coordinate system {F2} and the wheel center coordinate system {O i (i=1, 2, 3, 4)}; The yaw coordinate system {F1} is established on the yaw axis (302) of the passive compliance system (3), wherein the zF1 axis thereof coincides with the yaw axis (302) and the xF1 axis is parallel to the roll axis (303); The roll coordinate system {F2} is established on the roll axis (303) of the passive compliance system (3), wherein the zF2 axis coincides with the roll axis (303), and the yF2 axis is parallel to the left and right front magnetic wheel support axes; The wheel center coordinate system {O i (i=1,2,3,4)} coincides with the center of the adsorption magnetic wheel (523), yO i The axis coincides with the magnetic wheel support axis, zO i The axis points to the forward direction of the adsorption magnetic wheel (523); wherein i is the serial number of the corresponding adsorption magnetic wheel (523); The contact coordinate system between the multiple adsorption magnetic wheels (523) and the pipe wall is: Wheel wall contact coordinate system {P i (i=1,2,3,4)} coincides with the contact point of the wheel wall, yP i The axis points to the center of the magnetic wheel, zP i Pointing to the tangent direction of the wheel wall; where i is the serial number of the corresponding magnetic wheel; Instantaneous coincidence coordinate system of robot's center of mass The instantaneous coincidence with the robot's center of mass coordinate system {M} at time t; the instantaneous coincidence coordinate system when the wheel wall contacts Contact coordinate system with wheel wall {P i } coincide at the instant of time t.

9. The motion control method of a wheeled wall-climbing robot facing a high-curvature pipe diameter surface according to claim 5, characterized in that: The steps 4) to 5) are specifically as follows: According to the robot body structure and pipeline structure characteristics, the wheel wall contact coordinate system {P i (i=1,2,3,4)} relative wheel wall contact instantaneous coincidence coordinate system The derivative of the homogeneous change matrix at time t for: Wherein, R' represents the relative curvature radius, r represents the radius of the adsorption magnetic wheel (523), represents the angular velocity of the adsorption magnetic wheel (523), represents the rate of change of the geometric contact angle between the adsorption magnetic wheel (523) and the wall surface, and the coordinate transformation matrix of the body coordinate system of the wall-climbing robot is obtained by the relevant structural dimensions of the robot and the yaw angle and roll angle of the passive compliance system (3); The instantaneous coincidence coordinate system of the robot mass center coordinate system {M} relative to the robot mass center at time t is obtained by the transformation relationship between the body coordinate system of the wall climbing robot and the contact coordinate system of the plurality of adsorption magnetic wheels (523) and the pipe wall. The relationship is: After taking the derivative on both sides of the equation, we can get the following equation based on the principles of matrix inverse operation and differential operation: Among them, θ fi (i=1,2) are yaw angle and roll angle respectively, D i (i=1, 2, 3, 4) are the 6×4 Jacobian matrices of the four magnetic wheels respectively. Combining formula (5), we can obtain the kinematic model of the wall-climbing robot in the pipe curved surface environment: in, It includes the driving velocity vector of the driving adsorption magnetic wheel i, the rate of change of the rotation angle of the passive compliance system (3) and the rate of change of the wheel wall geometric contact angle; the rotation angle θ of the passive compliance system (3) f1 and θ f2 The wheel wall geometric contact angle δ is obtained by the detection and perception system (2). i Obtained through the geometric constraint relationship between the robot mechanism and the wall; D i The matrix is ​​the Jacobian matrix of the adsorption magnetic wheel i, which is a known matrix; The matrix is ​​the rate of change of posture, including the change of the robot's center of mass and the three angle rotation changes; that is: middle Three position changes and Three angle changes; Determining the driving speed of each adsorption magnetic wheel (523) of the wall-climbing robot according to the posture change rate Right now: The obtained value in formula (6) Substitute into formula (5) to obtain the rotation speed of the four magnetic wheels of the robot

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