Multi-degree-of-freedom rust removal polishing robot

Abstract

The invention discloses a multi-degree-of-freedom rust removal polishing robot, and relates to the technical field of ship rust removal, the multi-degree-of-freedom rust removal polishing robot comprises a robot chassis and a mechanical arm mounting platform, and the periphery of the robot chassis is connected with a bogie through four steering speed reducers to control the moving direction of walking wheels; the walking wheels are controlled by servo hub motors to move forwards or backwards in a steering mode, and the outer wall of the first Z-axis lead screw is connected with a Z-axis lifting plate through a movable sleeve. According to the multi-degree-of-freedom rust removal polishing robot, a three-dimensional point cloud map is constructed by using a laser radar, the curvature of a ship body curved surface and obstacles are recognized, and a basic path is generated in combination with the working radius of a six-axis mechanical arm; the omni-directional moving chassis ensures that the grinding head is perpendicular to the surface of the ship body, the dynamic balance system compensates shaking of the ship body through an X-axis sliding table, the speed is reduced in a curvature sudden change area, the grinding frequency is increased, the coverage rate is finally increased, and falling and separated rust slag is collected through the vacuum adsorption principle in cooperation with a recycling channel so as to avoid environmental pollution.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ship rust removal, in particular to a multi-degree-of-freedom rust removal and polishing robot. BACKGROUND

[0002] Ship rust removal operation is a core maintenance link in the repair industry, which is directly related to the safety of ship structure and service life. At present, the mainstream technology is still mainly traditional manual sand blasting (handheld spray gun) and semi-automatic high-pressure water jet equipment. According to the mandatory requirements of International Maritime Organization (IMO) "Performance Standard for Protective Coatings in Ships' Ballast Tanks" (PSPC), the ship surface treatment needs to reach Sa2.5 level cleanliness (ISO8501-1), and the residual amount of soluble salt is ≤50mg / m 2 ;

[0003] However, the prior art has significant defects:

[0004] It can be known from "Comparison of hull rust removal process efficiency" in Ship Engineering 2023, Vol. 45 that the daily average processing area of manual sand blasting is only 150-200㎡, which cannot meet the operation demand of 300,000㎡ of a single super large container ship (1.8 million TEU level), and the sand blasting process produces a large amount of heavy metal rust slag (Fe2O3 content exceeds 90%), which will cause environmental pollution, and has the hidden dangers of dust explosion in airtight cabin operation and manual high-altitude falling accidents. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a multi-degree-of-freedom rust removal and polishing robot, which solves the problems raised in the above background art.

[0006] To achieve the above purpose, the present application is realized by the following technical scheme: a multi-degree-of-freedom rust removal and polishing robot, comprising a robot chassis and a mechanical arm mounting platform, four steering reducers are connected to the four corners of the robot chassis to control the moving direction of the walking wheels, and servo hub motors are connected to the walking wheels to control the forward or backward movement of the walking wheels, a first Z-axis slide rod frame is fixed on the surface of the robot chassis, a first Z-axis motor is arranged on the top of the first Z-axis slide rod frame, a first Z-axis screw rod is connected to the bottom of the first Z-axis motor, a Z-axis upward and downward plate is connected to the outer wall of the first Z-axis screw rod through a moving sleeve, and there are two Z-axis upward and downward plates, and the two Z-axis upward and downward plates are connected through a horizontal slide rod;

[0007] An X-axis motor is fixed on the outer side of any Z-axis upward and downward plate, an X-axis screw rod is connected to the output end of the X-axis motor, and an X-axis sliding table is connected to the outer wall of the X-axis screw rod through a moving sleeve;

[0008] The surface of the X-axis sliding table is fixed with a second Z-axis sliding rod frame, the top of the second Z-axis sliding rod frame is fixed with a second Z-axis motor, and the bottom of the second Z-axis motor is connected with a second Z-axis screw rod, and the outer wall of the second Z-axis screw rod is connected with a secondary lifting seat through a moving sleeve.

[0009] The side of the secondary lifting seat is penetrated with a Y-axis sliding rod frame, one end of the Y-axis sliding rod frame is fixed with a Y-axis motor, and the other end of the Y-axis sliding rod frame is fixed with a mechanical arm mounting platform, the output end of the Y-axis motor is connected with a Y-axis screw rod, and the outer wall of the Y-axis screw rod is connected with the secondary lifting seat through a moving sleeve.

[0010] Further, the multi-degree-of-freedom derusting and polishing robot comprises the following steps:

[0011] S1, device deployment and environment modeling:

[0012] According to the work scene such as dry dock, wet dock and wharf, the robot is deployed near the ship body, connected with the AGV transportation module or the floating carrier, the initial attitude is calibrated by using the IMU inertial unit to ensure that the robot chassis is horizontally stable, the integrated laser radar and infrared sensor of the robot is started, the global scanning of the ship body surface is carried out, the curved surface curvature, the weld position and the obstacle coordinate data are collected, the three-dimensional point cloud map of the ship body is constructed based on the scanning data, and the key area is automatically identified;

[0013] S2, path planning:

[0014] Combined with the working radius of the six-axis mechanical arm, the system generates an initial derusting path according to the three-dimensional point cloud map, adopts the equal arc length method to plan the trajectory, ensures that the maximum coverage range of the mechanical arm end mill is realized, the robot chassis adjusts the initial attitude according to the path requirement, ensures that the mill is always perpendicular to the ship body surface, the mill is provided with a recycling channel around, the separated rust and slag falling through the vacuum adsorption principle are collected and recycled to the specified position through the channel such as pipeline;

[0015] S3, automatic derusting and dynamic compensation:

[0016] The system issues the initial path instruction, the robot chassis moves along the planned trajectory, the first Z-axis screw rod and the second Z-axis screw rod rotate to adjust the height of the mechanical arm mounting platform, so that the mechanical arm adapts to different work areas, the six-axis mechanical arm is designed to make the mill real-time fit the ship body curved surface and start derusting and polishing according to the preset pressure and speed through the coordinated movement of each joint;

[0017] When the IMU detects that the ship body is inclined or heaved, the real-time output shaking parameter triggers the reverse displacement of the X-axis sliding table according to the compensation formula, so as to offset the inertial impact and maintain the constant pressure of the mill;

[0018] The contact force data of the grinding head is collected by the force feedback sensor, and the speed is automatically reduced and the grinding times are increased in the curvature mutation area combined with the grinding head pressure and speed adjustment equation to ensure the uniformity of rust removal and the depth fluctuation is less than or equal to ±0.1mm;

[0019] When the infrared sensor detects a moving obstacle, the system immediately triggers the obstacle avoidance strategy, the first Z-axis lead screw and the second Z-axis lead screw lift the mechanical arm, the robot chassis synchronously plans a detour path, and the X-axis sliding table increases the speed to offset the brake inertia to avoid the grinding head from deviating;

[0020] S4, remote monitoring and cooperation:

[0021] The physical robot data, including but not limited to three-dimensional position, attitude trajectory, grinding head pressure, environmental point cloud, and transmission delay, are collected in real time through 5G or industrial WiFi, a simulation model consistent with the physical environment is constructed on the virtual end, the mechanical arm motion path is preplayed, the interference risk with the ship structure or equipment is detected, and the trajectory is optimized in advance;

[0022] The worker accesses the virtual model through the control software and fine-tunes the trajectory by dragging the virtual mechanical hand, and the dynamic balance system compensates for the pose deviation by the X-axis sliding table (8) to maintain the constant pressure of the grinding head;

[0023] The worker labels key points such as curvature mutations in the three-dimensional model, and the system automatically generates an optimized path and issues it to the physical robot for execution.

[0024] Further, in step S1, the key areas include but are not limited to bulb bow and side weld areas.

[0025] Further, in step S2, the update equation for adjusting the initial pose is as follows:

[0026]

[0027] The equation is used to control the omnidirectional movement of the robot chassis, and the linear speed and angular speed of the servo wheel hub motor are used to calculate the coordinates and heading angle of the robot chassis at the next time in real time, so as to dynamically adjust the pose of the robot chassis when navigating along the curved surface in ship rust removal, and ensure that the mechanical arm is always perpendicular to the ship surface.

[0028] Further, x t- , y t- : are the plane coordinates of the robot chassis in the world coordinate system at time t; θ t : is the heading angle of the chassis at time t, i.e. the angle of rotation around the z-axis; x t+Δt , y t+Δt : are the updated coordinates of the robot chassis in the world coordinate system at time t+Δt; θ t+Δt : is the updated heading angle of the robot chassis at time t+Δt, which is obtained by accumulating the angular velocity ω;

[0029] is a rotation matrix, used to convert the velocity in the body coordinate system into the displacement in the world coordinate system; is a velocity vector; v x is the linear velocity of the robot chassis in the x-axis direction of the body coordinate system; v y is the linear velocity of the robot chassis in the y-axis direction of the body coordinate system; Δt is the time interval of the pose update.

[0030] Further, in the step S3, the X-axis slide compensation displacement formula is as follows:

[0031]

[0032] Further, Δs x is the compensation displacement of the X-axis slide, that is, the active displacement perpendicular to the hull surface along the X-axis direction of the mechanical arm, used to offset the inertial impact; k is an angular acceleration compensation coefficient, which is determined through a frequency domain sweep frequency experiment; is the first derivative of the angular velocity, that is, the acceleration degree of the robot chassis or the hull rotating around the z-axis; b is an angular jerk compensation coefficient, which is determined through a frequency domain sweep frequency experiment; is the second derivative of the angular velocity, that is, the rate of change of the angular acceleration.

[0033] Further, the formula is used to eliminate the start-stop inertial impact, trigger the X-axis slide to increase speed when the walking wheel decelerates and brakes, the second derivative term suppresses instantaneous jitter, and maintain the constant pressure of the rust removal grinding head on the hull when the hull shakes or emergency obstacle avoidance.

[0034] Further, in the step S3, the grinding head pressure and speed adjustment equation is as follows:

[0035]

[0036] Further, v adjust is the adjusted grinding head travel speed; v0 is the reference speed; α is a speed adjustment coefficient, which is determined through a curvature gradient experiment; R is the curvature radius of the current position, which is derived in real time from the three-dimensional point cloud of the laser radar; R0 is the reference curvature radius;

[0037] The equation is used to optimize the complex curved surface machining quality, reduce the grinding head speed and increase the polishing times in the hull curvature mutation area such as a weld, and guarantee the uniformity of rust removal.

[0038] The present application provides a multi-degree-of-freedom rust removal and polishing robot, which has the following beneficial effects:

[0039] 1. The multi-degree-of-freedom rust removal and polishing robot uses a laser radar to construct a three-dimensional point cloud map, identifies the curvature of the hull surface and obstacles, generates a basic path in combination with the working radius of a six-axis mechanical arm; an omnidirectional mobile chassis ensures that the grinding head is perpendicular to the hull surface, a dynamic balance system compensates for hull sway through an X-axis sliding table, reduces speed and increases the number of polishing in areas with sudden changes in curvature, ultimately improves coverage, and cooperates with a recovery channel to collect and recover separated rust and debris to a designated location through a channel such as a pipeline through vacuum adsorption principle to avoid environmental pollution, and workers can remotely view device status, environmental map and process parameters, intervene in work through path correction, virtual demonstration and other modes, combined with force feedback to reduce manual load, and remote operation improves safety and efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0040] Fig. 1 Figure 1 is a schematic diagram of the robot chassis to Y-axis screw structure of the multi-degree-of-freedom rust removal and polishing robot of the present application;

[0041] Fig. 2 Figure 2 is a schematic diagram of the rust removal and polishing robot model motion simulation process of the multi-degree-of-freedom rust removal and polishing robot of the present application;

[0042] Fig. 3 Figure 3 is a schematic diagram of the main process of mechanical arm digital twin model collaborative simulation of the multi-degree-of-freedom rust removal and polishing robot of the present application.

[0043] In the figure: 1, robot chassis; 2, first Z-axis sliding rod frame; 3, first Z-axis motor; 4, first Z-axis screw; 5, Z-axis upward and downward plate; 6, X-axis motor; 7, X-axis screw; 8, X-axis sliding table; 9, second Z-axis sliding rod frame; 10, second Z-axis motor; 11, second Z-axis screw; 12, two-stage lifting seat; 13, Y-axis sliding rod frame; 14, Y-axis motor; 15, mechanical arm mounting platform; 16, Y-axis screw. DETAILED DESCRIPTION

[0044] The embodiments of the present application will be further described in detail below in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0045] As Figs. 1-3As shown, the present application provides technical solutions: a multi-degree-of-freedom derusting and polishing robot, comprising a robot chassis 1 and a mechanical arm mounting platform 15, the four corners of the robot chassis 1 are connected with bogies through four steering reducers to control the moving direction of the walking wheels, and the forward or backward movement of the walking wheels is controlled through a servo wheel hub motor, and the surface of the robot chassis 1 is fixed with a first Z-axis slide rod frame 2 on both sides, the top of the first Z-axis slide rod frame 2 is provided with a first Z-axis motor 3, and the bottom of the first Z-axis motor 3 is connected with a first Z-axis screw rod 4, the outer wall of the first Z-axis screw rod 4 is connected with a Z-axis upward and downward plate 5 through a moving sleeve, and the Z-axis upward and downward plate 5 is two in number, and the Z-axis upward and downward plates 5 are connected through a transverse slide rod;

[0046] The outer side of any Z-axis upward and downward plate 5 is fixed with an X-axis motor 6, and the output end of the X-axis motor 6 is connected with an X-axis screw rod 7, and the outer wall of the X-axis screw rod 7 is connected with an X-axis sliding table 8 through a moving sleeve;

[0047] The surface of the X-axis sliding table 8 is fixed with a second Z-axis slide rod frame 9 around the four corners, the top of the second Z-axis slide rod frame 9 is fixed with a second Z-axis motor 10, and the bottom of the second Z-axis motor 10 is connected with a second Z-axis screw rod 11, and the outer wall of the second Z-axis screw rod 11 is connected with a secondary lifting seat 12 through a moving sleeve;

[0048] The side surface of the secondary lifting seat 12 is penetrated through with a Y-axis slide rod frame 13, one end of the Y-axis slide rod frame 13 is fixed with a Y-axis motor 14, and the other end of the Y-axis slide rod frame 13 is fixed with a mechanical arm mounting platform 15, the output end of the Y-axis motor 14 is connected with a Y-axis screw rod 16, and the outer wall of the Y-axis screw rod 16 is connected with the secondary lifting seat 12 through a moving sleeve;

[0049] The specific operation is as follows, the multi-axis designed mechanical arm is mounted at the mechanical arm mounting platform 15, the end of the mechanical arm is provided with a grinding head for derusting, polishing and polishing work, the first Z-axis screw rod 4 is driven by the first Z-axis motor 3 to rotate clockwise or counterclockwise to make the Z-axis upward and downward plate 5 lift, so as to adjust the height of the mechanical arm, at the same time, the second Z-axis screw rod 11 is driven by the second Z-axis motor 10 to rotate clockwise or counterclockwise to make the secondary lifting seat 12 further adjust the height of the mechanical arm on the lifting height of the Z-axis upward and downward plate 5;

[0050] And the X-axis sliding table 8 is translated along the X-axis direction by driving the X-axis screw rod 7 to rotate clockwise or counterclockwise through the X-axis motor 6, so as to adjust the X-axis direction position of the mechanical arm;

[0051] And the Y-axis slide rod frame 13 is translated along the Y-axis direction by driving the Y-axis screw rod 16 to rotate clockwise or counterclockwise through the Y-axis motor 14, so that the mechanical arm mounting platform 15 carries the mechanical arm to adjust the Y-axis direction position;

[0052] And the walking wheels are driven by servo wheel hub motors to adjust the advancing direction (i.e. control the forward and backward movement) to adjust the position of the robot chassis 1, and each walking wheel is further connected with a motor for controlling the rotation angle, the motor reduces the rotation speed and amplifies the torque through a speed reducer, and at the same time, the angle control precision is amplified through the speed reduction ratio, such as a speed reduction ratio of 10:1, 10° rotation of the motor corresponds to 1° rotation of the wheel, and the control resolution is improved by 10 times.

[0053] Based on the above description, the multi-degree-of-freedom rust removal and polishing robot comprises the following steps:

[0054] S1, device deployment and environment modeling:

[0055] According to the work scene such as dry dock, wet dock and wharf, the robot is deployed near the ship body, connected with the AGV transportation module or floating carrier, the initial attitude is calibrated by using the IMU inertial unit to ensure the horizontal stability of the robot chassis 1, the integrated laser radar and infrared sensor of the robot is started, the global scanning of the ship body surface is carried out, the curved surface curvature, weld position and obstacle coordinate data are collected, and the three-dimensional point cloud map of the ship body is constructed based on the scanning data, and the key areas are automatically identified, including but not limited to bulb bow, side weld area;

[0056] S2, path planning:

[0057] Combined with the working radius of the six-axis mechanical arm, the system generates an initial rust removal path according to the three-dimensional point cloud map, adopts the equal arc length method to plan the trajectory, ensures that the maximum coverage range of the mechanical arm end mill, the robot chassis 1 adjusts the initial attitude according to the path requirement, ensures that the mill head is always perpendicular to the ship body surface, the mill head is provided with a recycling channel, the separated rust and slag falling through the vacuum adsorption principle is collected and recycled to the specified position through the channel such as pipeline;

[0058] The update equation for adjusting the initial attitude is as follows:

[0059]

[0060] The equation is used to control the omnidirectional movement of the robot chassis 1, through the linear speed and angular speed of the servo wheel hub motor, the coordinates and orientation angle of the robot chassis at the next time are calculated in real time, so as to dynamically adjust the attitude of the robot chassis 1 when navigating along the curved surface in the ship rust removal, and ensure that the mechanical arm is always perpendicular to the surface of the ship body, wherein the mechanical arm adopts a multi-axis mechanical arm which can be adjusted at multiple angles, so as to realize the multi-angle orientation adjustment of the mill head while the robot chassis 1 cooperates with the structure of the surface to realize the three-axis movement, such as a four-axis mechanical arm.

[0061] x t- , y t- : the planar coordinates of the robot chassis 1 in the world coordinate system at time t; θ t : the heading angle of the chassis at time t, i.e. the angle of rotation around the z axis; xt+Δt , y t+Δt : is the updated coordinate of robot chassis 1 in the world coordinate system at time t+Δt; θ t+Δt : is the updated heading angle of robot chassis 1 at time t+Δt, which is accumulated by angular velocity ω; is a rotation matrix used to convert the velocity in the body coordinate system into displacement in the world coordinate system; is a velocity vector; v x : is the linear velocity of robot chassis 1 in the x-axis direction of the body coordinate system; v y : is the linear velocity of robot chassis 1 in the y-axis direction of the body coordinate system; Δt: is the time interval of pose update;

[0062] S3, automatic rust removal and dynamic compensation:

[0063] The system issues an initial path instruction, and the robot chassis 1 moves along the planned trajectory. The first Z-axis lead screw 4 and the second Z-axis lead screw 11 rotate to adjust the height of the mechanical arm mounting platform 15, so that the mechanical arm adapts to different work areas. The mechanical arm is designed with six axes, which cooperates with each joint to make the grinding head real-time fit the ship body curve and start rust removal and polishing according to the preset pressure and speed;

[0064] When the IMU detects that the ship body is tilted or jolted, it outputs the shaking parameters in real time to trigger the X-axis sliding table 8 to move in the opposite direction according to the compensation formula, so as to offset the inertial impact and maintain the constant pressure of the grinding head;

[0065] The compensation displacement formula of the X-axis sliding table 8 is as follows:

[0066]

[0067] Δs x : is the compensation displacement of the X-axis sliding table 8, which is the active displacement perpendicular to the ship body surface along the X-axis direction of the mechanical arm, used to offset the inertial impact; k: is the angular acceleration compensation coefficient, which is determined by frequency domain sweep frequency experiment; is the first derivative of angular velocity, that is, the acceleration degree of robot chassis 1 or ship body rotating around z-axis; b: is the angular jerk compensation coefficient, which is determined by frequency domain sweep frequency experiment; is the second derivative of angular velocity, that is, the rate of change of angular acceleration;

[0068] This formula is used to eliminate the start-stop inertial impact. When the walking wheel is decelerated and braked, the X-axis sliding table 8 is triggered to speed up. The second derivative term suppresses the instantaneous jitter. When the ship body shakes or emergency obstacle avoidance, the constant pressure of the rust removal grinding head on the ship body is maintained;

[0069] The contact force data of the grinding head is collected by the force feedback sensor, and the grinding head pressure and speed adjustment equation is used in the curvature mutation area to automatically reduce the speed and increase the grinding times to ensure the uniformity of rust removal, and the depth fluctuation is ≤±0.1mm;

[0070] The grinding head pressure and speed adjustment equation is as follows:

[0071]

[0072] v adjust : the adjusted grinding head speed; v0: the reference speed; a: the speed adjustment coefficient, which is determined by the curvature gradient experiment; R: the curvature radius of the current position, which is derived from the three-dimensional point cloud of the laser radar in real time; R0: the reference curvature radius;

[0073] The equation is used to optimize the machining quality of complex curved surfaces, reduce the grinding head speed and increase the grinding times in the curvature mutation area of the ship body such as the weld, and ensure the uniformity of rust removal;

[0074] When the infrared sensor detects a moving obstacle, the system immediately triggers the obstacle avoidance strategy, the first Z-axis lead screw 4 and the second Z-axis lead screw 11 lift the mechanical arm, the robot chassis 1 synchronously plans a detour path, and the X-axis sliding table 8 increases the speed to offset the brake inertia to avoid the grinding head deviation;

[0075] S4, remote monitoring and cooperation:

[0076] The physical robot data is collected in real time through 5G or industrial WiFi, including but not limited to three-dimensional position, attitude trajectory, grinding head pressure, environment point cloud, transmission delay, and the virtual end constructs a simulation model consistent with the physical environment, preforms the mechanical arm motion path, detects the interference risk with the ship body structure or equipment, and optimizes the trajectory in advance;

[0077] The worker accesses the virtual model through the control software, drags the virtual mechanical hand to fine-tune the trajectory, dynamically balances the system linkage X-axis sliding table 8 to compensate for the pose deviation, and maintains the constant pressure of the grinding head;

[0078] The worker labels key points such as curvature mutations in the three-dimensional model, and the system automatically generates an optimized path and issues it to the entity robot for execution;

[0079] Based on the above description, the application uses laser radar to construct a three-dimensional point cloud map, identifies the curvature of the hull surface and obstacles, and generates a basic path in combination with the working radius of the six-axis mechanical arm; the omnidirectional mobile chassis ensures that the grinding head is perpendicular to the hull surface, the dynamic balance system compensates for the hull sway through the X-axis sliding table 8, reduces the speed and increases the polishing frequency in the area with sudden change of curvature, finally improves the coverage rate, and cooperates with the recovery channel, collects the rust and slag separated by vacuum adsorption principle and recovers to the designated position through the channel such as pipeline to avoid environmental pollution, and workers can remotely view the equipment state, environmental map and process parameters, intervene in the operation through path correction, virtual demonstration and other modes, combined with force feedback to reduce the artificial load, and remote operation improves safety and efficiency.

[0080] Embodiments of the application are presented for the purpose of illustration and description, and are not intended to be exhaustive or to limit the application to the precise forms disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Embodiments were chosen and described in order to best explain the principles of the application and its practical application, and to enable others skilled in the art to understand the application for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

1. A multi-degree of freedom derusting and polishing robot comprising a robot chassis (1) and a robot arm mounting platform (15), characterized in that: The robot chassis (1) is connected to the bogie through four steering reducers to control the moving direction of the walking wheels, and is controlled by the servo wheel hub motor to control the forward or backward of the walking wheel steering, and the surface of the robot chassis (1) is fixed with a first Z-axis slide rod frame (2), the top of the first Z-axis slide rod frame (2) is provided with a first Z-axis motor (3), and the bottom of the first Z-axis motor (3) is connected with a first Z-axis screw rod (4), the outer wall of the first Z-axis screw rod (4) is connected with a Z-axis upward and downward plate (5) through a moving sleeve, and the Z-axis upward and downward plate (5) is shared by two, and the Z-axis upward and downward plates (5) are connected through transverse slide rods; The outer side of any Z-axis upward and downward plate (5) is fixed with an X-axis motor (6), and the output end of the X-axis motor (6) is connected with an X-axis screw rod (7), and the outer wall of the X-axis screw rod (7) is connected with an X-axis sliding table (8) through a moving sleeve; The surface of the X-axis sliding table (8) is fixed with a second Z-axis slide rod frame (9) around, the top of the second Z-axis slide rod frame (9) is fixed with a second Z-axis motor (10), and the bottom of the second Z-axis motor (10) is connected with a second Z-axis screw rod (11), the outer wall of the second Z-axis screw rod (11) is connected with a secondary lifting seat (12) through a moving sleeve; The side surface of the secondary lifting seat (12) is penetrated through with a Y-axis slide rod frame (13), one end of the Y-axis slide rod frame (13) is fixed with a Y-axis motor (14), and the other end of the Y-axis slide rod frame (13) is fixed with a mechanical arm mounting platform (15), the output end of the Y-axis motor (14) is connected with a Y-axis screw rod (16), and the outer wall of the Y-axis screw rod (16) is connected with the secondary lifting seat (12) through a moving sleeve.

2. The multi-degree of freedom derusting and polishing robot according to claim 1, characterized in that: The multi-degree-of-freedom derusting and polishing robot comprises the following steps: S1, device deployment and environment modeling: According to the work scene such as dry dock, wet dock and wharf, the robot is deployed near the ship body, connected with AGV transportation module or floating carrier, the initial attitude is calibrated by IMU inertial unit to ensure that the robot chassis (1) is stable and horizontal, the integrated laser radar and infrared sensor of the robot is started, the whole domain scanning of the ship body surface is carried out, the curved surface curvature, weld position and obstacle coordinate data are collected, and the three-dimensional point cloud map of the ship body is constructed based on the scanning data, and the key area is automatically identified; S2, path planning: Combined with the working radius of the six-axis mechanical arm, the system generates an initial derusting path according to the three-dimensional point cloud map, plans the trajectory by using the equal arc length method, ensures that the maximum coverage range of the mechanical arm end mill is realized, the robot chassis (1) adjusts the initial attitude according to the path requirement, ensures that the mill head is always perpendicular to the ship body surface, the mill head is provided with a recycling channel, the separated rust and slag falling through the vacuum adsorption principle is collected and recycled to the specified position through the channel such as pipeline; S3, automatic derusting and dynamic compensation: The system issues an initial path instruction, the robot chassis (1) moves along the planned trajectory, the first Z-axis lead screw (4) and the second Z-axis lead screw (11) rotate to adjust the height of the mechanical arm mounting platform (15), so that the mechanical arm adapts to different work areas, and the mechanical arm is designed as a six-axis design, which cooperates through each joint to make the grinding head real-time fit the ship body curve and start rust removal and polishing according to the preset pressure and speed; When the IMU detects that the ship body is tilted or heaved, the real-time output of the shaking parameter triggers the reverse displacement of the X-axis sliding table (8) according to the compensation formula, so as to offset the inertial impact and thus maintain the constant pressure of the grinding head; Through the force feedback sensor, the contact force data of the grinding head is collected, and the grinding head pressure and speed adjustment equation is combined to automatically reduce the speed and increase the polishing times in the curvature mutation area, so as to ensure the uniformity of rust removal and the depth fluctuation is less than or equal to ±0.1mm. When the infrared sensor detects a moving obstacle, the system immediately triggers the obstacle avoidance strategy, the first Z-axis lead screw (4) and the second Z-axis lead screw (11) lift the mechanical arm, the robot chassis (1) synchronously plans a bypass path, and the X-axis sliding table (8) increases the speed to offset the brake inertia, so as to avoid the deviation of the grinding head. S4, remote monitoring cooperation: Through 5G or industrial WiFi, physical robot data is collected in real time, including but not limited to three-dimensional position, attitude trajectory, grinding head pressure, environmental point cloud, transmission delay, a virtual end constructs a simulation model consistent with the physical environment, preforms the mechanical arm movement path, detects the interference risk with the ship body structure or equipment, and optimizes the trajectory in advance; Workers access the virtual model through the control software, drag the virtual mechanical hand to fine-tune the trajectory, dynamically balance the system linkage X-axis sliding table (8) to compensate for the pose deviation, and maintain the constant pressure of the grinding head; Workers mark key points such as curvature mutations in the three-dimensional model, and the system automatically generates an optimized path and issues it to the entity robot for execution.

3. A multi-degree of freedom derusting and polishing robot according to claim 2, characterized in that: In the step S1, the key areas include but are not limited to the bulb bow and the side weld area.

4. The multi-degree of freedom derusting and polishing robot according to claim 2, characterized in that: In the step S2, the update equation for adjusting the initial pose is as follows: This equation is used to control the omnidirectional movement of the robot chassis (1), and through the linear speed and angular speed of the servo wheel hub motor, the coordinates and orientation angle of the robot chassis at the next moment are calculated in real time, so as to dynamically adjust the pose of the robot chassis (1) when navigating along the curved surface in ship rust removal, and ensure that the mechanical arm is always perpendicular to the ship body surface.

5. A multi-degree of freedom derusting and polishing robot according to claim 4, characterized in that: x t- , y t- : are the planar coordinates of the robot chassis (1) in the world coordinate system at time t; θ t : is the heading angle of the chassis at time t, i.e. the angle of rotation around the z-axis; x t+Δt , y t+Δt : are the updated coordinates of the robot chassis (1) in the world coordinate system at time t+Δt; θ t+Δt : is the updated heading angle of the robot chassis (1) at time t + Δt, which is accumulated from the angular velocity ω; is the rotation matrix used to convert the velocity in the body frame to the displacement in the world frame; is the velocity vector; v x : is the linear velocity of the robot chassis (1) in the x-axis direction of the body frame; v y : is the linear velocity of the robot chassis (1) in the y-axis direction of the body frame; Δt: is the time interval for pose updating.

6. The multi-degree of freedom derusting and polishing robot according to claim 2, characterized in that: In the step S3, the X-axis sliding table (8) compensation displacement formula is as follows:

7. A multi-degree of freedom derusting and polishing robot according to claim 6, characterized in that: Δs x : is the compensation displacement of X-axis slide table (8), that is, the active displacement perpendicular to the surface of the ship body along the X-axis direction of the mechanical arm, which is used to offset the inertial impact; k: is the angular acceleration compensation coefficient, which is determined by frequency domain sweep frequency experiment; is the first derivative of angular velocity, that is, the acceleration degree of the robot chassis (1) or the ship body rotating around the z-axis; b: is the angular jerk compensation coefficient, which is determined by the frequency domain sweep experiment; is the second derivative of angular velocity, i.e., the rate of change of angular acceleration.

8. The multi-degree of freedom derusting and polishing robot according to claim 6, characterized in that: This formula is used to eliminate the start-stop inertial impact, and when the walking wheel is decelerated and braked, the X-axis sliding table (8) is triggered to increase the speed, and the second derivative term suppresses the instantaneous jitter, so as to maintain the constant pressure of the rust removal grinding head on the ship body when the ship body shakes or emergency obstacle avoidance.

9. The multi-degree of freedom derusting and polishing robot according to claim 2, characterized in that: In the step S3, the grinding head pressure and speed adjustment equation is as follows:

10. The multi-degree of freedom rust removal and polishing robot according to claim 9, characterized in that: v adjust : is the adjusted travel speed of the grinding head; v0: is the reference speed; a: is the speed adjustment coefficient, which is determined by the curvature gradient experiment; R: is the curvature radius of the current position, which is derived from the real-time three-dimensional point cloud of the laser radar; R0: is the reference curvature radius; This equation is used to optimize the processing quality of complex curved surfaces, and in the ship body curvature mutation area such as the weld, the grinding head speed is reduced and the polishing times are increased, so as to ensure the uniformity of rust removal.

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