Wall-climbing robot permanent magnet adsorption device with adjustable magnetic force and control method

Abstract

The invention belongs to the technical field of magnetic adsorption wall-climbing robots, and particularly relates to a wall-climbing robot permanent magnet adsorption device with adjustable magnetic force and a control method. The device comprises an electric push rod, a connecting rod, a swing arm, a supporting frame, an arc-shaped permanent magnet, an ultrasonic sensor, a pivot, a rigid arm and a pressure sensor. The pivot is mounted on an axle of the wall-climbing robot and is fixedly connected with the lower end of a frame supporting arm of the wall-climbing robot; one end of the rigid arm is fixedly connected with the middle of a frame supporting arm of the wall-climbing robot, the electric push rod is located at the other end of the rigid arm, the tail end of a telescopic rod of the electric push rod is rotationally connected with one end of the connecting rod, the other end of the connecting rod is rotationally connected with one end of the swing arm, and the other end of the swing arm is fixedly connected with the upper end of the supporting frame. The arc-shaped permanent magnet is located at the lower end of the support; the expansion amount is controlled by controlling the rotation time of a motor of the electric push rod, so that the distance between a magnetic force concentration point of the arc-shaped permanent magnet and the wall surface is controlled; and the push-pull force variation is controlled by controlling the driving force of the electric push rod, so that the actual magnetic adsorption force is controlled. The magnetic force can be adjusted through the rotating motion of the permanent magnet, so that the robot can adapt to different wall surfaces and complete different actions.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic adsorption wall-climbing robots, and in particular relates to a permanent magnetic adsorption device of a wall-climbing robot with adjustable magnetic force and a control method thereof. Background Art

[0002] Steel bridges are exposed to the outdoors and are affected by natural factors such as wind, sun, rain, and moisture for a long time. Steel bridges near the sea are even corroded by chloride ions, and their surfaces will gradually rust and corrode, which will not only significantly shorten the service life of the structure, but may also cause serious safety hazards. Therefore, steel bridges need to be inspected and maintained regularly. Traditional methods usually rely on workers to work at high altitudes, which is not only inefficient, but also difficult to effectively guarantee the safety of workers. Wall-climbing robots can replace manual labor to inspect and maintain steel bridges. The adsorption system is a vital component of wall-climbing robots, and traditional magnetic adsorption devices usually rely on fixed magnetic force to attach to the working wall surface. However, with the increasing demand for robots to operate under different curvatures and complex walls, traditional magnetic adsorption devices have gradually exposed defects such as high energy consumption, insufficient durability, and inflexible magnetic force adjustment, which seriously affect the efficiency and adaptability of wall-climbing robots in practical applications.

[0003] The patent application with publication number CN107310640A discloses a crawler-type electromagnetic adsorption wall-climbing robot walking mechanism, which uses electric control technology to accurately control the adsorption force of the electromagnet, and can achieve climbing on vertical or horizontal walls. Although the electromagnetic adsorption device of the wall-climbing robot can change the magnetic force by adjusting the current, there is a risk of falling when the power is off. The patent application with publication number CN102745278A discloses a permanent magnetic adsorption wall-climbing robot with a self-locking device, which realizes wall climbing movement through the cooperation of the sprocket drive system and the permanent magnetic adsorption unit. However, the adsorption force generated by the device is fixed and cannot be adjusted according to the needs of the working environment. When strong adsorption force is not required, providing too large an adsorption force will cause excessive resistance during the robot's movement, affecting the operating efficiency of the wall-climbing robot. When the robot leaves the wall, the demagnetization process of the permanent magnetic adsorption unit is relatively complicated and inconvenient, affecting the operating efficiency.

[0004] In summary, although the electromagnetic adsorption device has the characteristics of adjustable magnetic force, it is difficult to adapt to long-term and high-intensity work tasks due to its high energy consumption, limited endurance and insufficient durability, and there is a risk of falling when the power is off. With its advantages of low energy consumption and durability, the permanent magnetic adsorption device can effectively meet the needs of long-term operation of the wall-climbing robot. However, the adsorption force generated by the traditional permanent magnetic adsorption device is usually constant and cannot be adjusted according to actual needs. On the one hand, due to the different adsorption forces required on different wall surfaces such as vertical wall surfaces, inclined wall surfaces, wall intersection angles and certain local concave and convex parts of the wall surface, excessive adsorption force will cause difficulty in the movement of the wall-climbing robot, and too small adsorption force will cause instability. On the other hand, after the wall-climbing robot completes the operation, the large constant adsorption force will make it difficult to detach from the wall surface, and forced detachment will cause damage to the robot structure and even the wall surface. Although a few magnetic adsorption devices have the function of adjustable magnetic force, the adjustment direction is often consistent with the magnetic force, and the requirements for adjusting the external force are high, and the efficiency is low, which limits the adaptability and operational flexibility of the robot in different operation scenarios. Summary of the invention

[0005] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a permanent magnetic adsorption device and a control method for a wall-climbing robot with adjustable magnetic force.

[0006] The present invention solves the technical problem by adopting the following technical solution:

[0007] A permanent magnetic adsorption device for a wall-climbing robot with adjustable magnetic force, characterized in that the device comprises an electric push rod, a connecting rod, a swing arm, a support frame, an arc-shaped permanent magnet, an ultrasonic sensor, a pivot, a rigid arm and a pressure sensor; the pivot is installed on the axle of the wall-climbing robot and is fixedly connected to the lower end of the support arm of the wall-climbing robot frame; one end of the rigid arm is fixedly connected to the middle part of the support arm of the wall-climbing robot frame, the electric push rod is located at the other end of the rigid arm and the telescopic direction is always along the vertical direction, the telescopic rod end of the electric push rod is rotatably connected to one end of the connecting rod, the other end of the connecting rod is rotatably connected to one end of the swing arm, the other end of the swing arm is fixedly connected to the upper end of the support frame, the upper end of the support frame is rotatably connected to the pivot at the same time, and the arc-shaped permanent magnet is located at the lower end of the support frame; the electric push rod drives the arc-shaped permanent magnet to rotate, adjusts the distance between the arc-shaped permanent magnet and the wall surface, thereby realizing adjustable magnetic adsorption force, and at the same time makes the magnetic adsorption force adjustment direction along the tangent direction of the magnetic force line;

[0008] The ultrasonic sensor is located on the support frame and is used to measure the distance between the installation position and the wall surface; the pressure sensor is located between the support frame and the pivot and is used to measure the force applied by the support frame to the pivot.

[0009] Furthermore, the control method of the device includes the following contents:

[0010] The force analysis of the wall-climbing robot is carried out on the wall surface to obtain the magnetic force design value F d , calculate the standard value d0 of the distance between the magnetic force concentration point of the arc-shaped permanent magnet and the wall surface according to formula (1), and the magnetic force concentration point of the arc-shaped permanent magnet is the center point of the outer edge of the arc-shaped permanent magnet;

[0011]

[0012] Where k is a constant;

[0013] Based on the distance data measured by the ultrasonic sensor, according to the geometric relationship, the distance d between the magnetic concentration point of the arc permanent magnet and the wall surface is obtained; according to the geometric relationship, the relationship between the angular change Δξ of the arc permanent magnet and d and d0 can be obtained as follows:

[0014]

[0015] Where d2 is the distance between the magnetic force concentration point of the arc-shaped permanent magnet and the pivot axis, and r is the wheel radius;

[0016] That is, the relationship between the angular change Δξ of the arc-shaped permanent magnet and the extension ΔL of the electric push rod is:

[0017]

[0018] Combining equations (2) and (12), we can get the calculation formula for the extension and contraction amount ΔL of the electric push rod:

[0019]

[0020] Where, L2 is the length of the connecting rod, L1 is the projection length of the connecting rod in the vertical direction in the initial state, d1 is the length of the swing arm, and x2 is the projection length of the swing arm in the horizontal direction in the initial state;

[0021] By controlling the rotation time of the electric push rod motor and the extension and contraction amount of the electric push rod, the distance between the magnetic force concentration point of the arc-shaped permanent magnet and the wall surface is made equal to the standard distance value;

[0022] Based on the force data measured by the pressure sensor, the force analysis of the arc permanent magnet is carried out to obtain the actual magnetic adsorption force F; according to the actual magnetic adsorption force F and the magnetic design value F d , the push-pull force variation ΔN of the electric push rod can be obtained as:

[0023]

[0024] Where α1 is the angle between the magnetic adsorption force and the vertical direction, β1 is the angle between the electric push rod and the connecting rod in the initial state, and γ is the angle between the connecting rod and the swing arm in the initial state;

[0025] By controlling the driving force of the electric push rod, the change in the push and pull force of the electric push rod is controlled so that the actual magnetic adsorption force is equal to the magnetic design value.

[0026] Furthermore, to realize the rotational motion of the arc-shaped permanent magnet, the driving force N1 of the electric push rod must meet the following conditions:

[0027]

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention is an adjustable magnetic adsorption device based on permanent magnetic adsorption technology. Compared with the traditional electromagnetic adsorption device, it has the advantage of stable magnetic force and no risk of falling in the case of power failure. The position of the arc-shaped permanent magnet is adjusted by the rotational movement of the arc-shaped permanent magnet, and then the distance between the magnetic force concentration point of the arc-shaped permanent magnet and the wall surface is adjusted, so that the magnetic adsorption force generated by the permanent magnet can be adjusted. The larger the distance, the smaller the magnetic adsorption force, and the smaller the distance, the larger the magnetic adsorption force, so that the device can adapt to different working environments such as horizontal wall surfaces, vertical wall surfaces, inclined wall surfaces, wall intersection angles, concave and convex wall surfaces, or different actions such as robot installation and detachment. After the task is completed, the prior art generally increases the distance between the wall-climbing robot and the wall surface by inserting additional pads, thereby reducing the magnetic adsorption force to make the wall-climbing robot detach. This method is not only cumbersome to operate, but also increases the risk of high-altitude operations. After the task is completed, the present invention reduces the magnetic adsorption force by increasing the distance between the arc-shaped permanent magnet and the wall surface, so that the wall-climbing robot is easier to detach from the wall surface, and no additional measures are required, which reduces the risk of high-altitude operations. By changing the position of the arc-shaped permanent magnet, the direction of the magnetic field can also be changed, which greatly increases the efficiency of increasing or decreasing the magnetic force under unit force, which not only speeds up the adjustment process but also improves the convenience of using the device.

[0030] The arc-shaped permanent magnet moves in a circular motion around the pivot axis, and the direction of motion is tangential to the magnetic force lines. The magnetic adsorption force is adjusted tangentially rather than normally to the magnetic force lines, which overcomes the defect of providing a large axial force when adjusting the magnetic force along the normal direction of the magnetic force lines. The required external force for adjustment is greatly reduced, the size of the supporting structure is reduced, the weight of the wall-climbing robot is reduced, and energy consumption is saved.

[0031] 2. The application of the external torque required to adjust the magnetic adsorption force adopts the lever principle. The force is applied to the end of the swing arm through the connecting rod. With the help of the amplification effect of the swing arm length, a small force can produce a large driving torque, thereby driving the arc-shaped permanent magnet to rotate, which greatly improves the efficiency of magnetic force regulation and avoids the problems of increased robot cost and complex control system caused by directly adding a torque motor. The telescopic motion of the electric push rod is converted into the rotational motion of the arc-shaped permanent magnet through the connecting rod. The power output of the electric push rod is stable and the power output direction is constant. The precise regulation of the magnetic adsorption force is achieved by controlling the electric push rod.

[0032] 3. Adaptive dynamic control of magnetic adsorption force is realized based on the data collected by ultrasonic sensors and pressure sensors. By controlling the extension and extension amount and driving force of the electric push rod, the distance between the magnetic concentration point of the arc-shaped permanent magnet and the wall surface and the actual magnetic adsorption force are adjusted respectively, so as to realize the coordinated control of distance and magnetic adsorption force and ensure the adsorption effect of the magnetic adsorption device.

[0033] 4. The present invention effectively solves the problem that the magnetic adsorption force is difficult to flexibly adjust when the wall-climbing robot is operating on the surface of a steel bridge. In particular, when the robot is transitioning to the wall or leaving the surface of the steel bridge, the magnetic force is dynamically adjusted to avoid instability caused by insufficient or excessive magnetic force, thereby significantly improving the safety and reliability of the wall-climbing robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall structure;

[0035] Figure 2 It is a partial structural schematic diagram;

[0036] Figure 3 It is a schematic diagram of the structure of the electric linear actuator;

[0037] Figure 4 It is a schematic diagram of the structure of the pivot;

[0038] Figure 5 This is a schematic diagram of the connection between the axle and the wheels of the wall-climbing robot;

[0039] Figure 6 It is a schematic diagram of the positions of arc-shaped permanent magnets on different walls;

[0040] Figure 7 It is a schematic diagram of the position of the arc-shaped permanent magnet before and after leaving the wall;

[0041] Figure 8 It is a schematic diagram of the state of the magnetic adsorption device at the intersection angle of the wall;

[0042] Fig. 9 It is the force analysis diagram of the magnetic adsorption device in the initial state and after the electric push rod moves;

[0043] Fig.10 It is a force analysis diagram to determine the driving force of the electric linear actuator;

[0044] In the figure: 1. Electric push rod; 2. Limit switch; 3. Intelligent machine lock; 4. Connecting rod; 5. Swing arm; 6. Support frame; 7. Arc permanent magnet; 8. Control panel; 9. Frame support arm; 10. Wheel; 11. Ultrasonic sensor; 12. Axle; 13. Pivot; 14. Rigid arm; 15. Pressure sensor; 16. Sealed bearing. DETAILED DESCRIPTION

[0045] Specific embodiments are given below in conjunction with the accompanying drawings. The specific embodiments are only used to introduce the technical solutions of the present invention in detail and are not intended to limit the protection scope of the present application.

[0046] The present invention provides a permanent magnetic adsorption device for a wall-climbing robot with adjustable magnetic force (hereinafter referred to as the device, see Figures 1 to 10 ), including an electric push rod 1, a connecting rod 4, a swing arm 5, a support frame 6, an arc-shaped permanent magnet 7, a control panel 8, an ultrasonic sensor 11, a pivot 13, a rigid arm 14 and a pressure sensor 15;

[0047] Among them, the pivot 13 is installed at one end of the axle 12 of the wall-climbing robot through a sealed bearing 16, the axle 12 can rotate relative to the pivot 13, and the other end of the axle 12 is installed with a wheel 10; the lower end of the frame support arm 9 of the wall-climbing robot is fixedly connected to the pivot 13, and the frame support arm 9 and the wheel 10 play a role in supporting the wall-climbing robot; one end of the rigid arm 14 is fixedly connected to the middle part of the frame support arm 9, the electric push rod 1 is fixedly installed on the other end of the rigid arm 14 and the telescopic direction of the electric push rod 1 is always along the vertical direction, the telescopic rod end of the electric push rod 1 is rotatably connected to one end of the connecting rod 4, the other end of the connecting rod 4 is rotatably connected to one end of the swing arm 5, the other end of the swing arm 5 is fixedly connected to the upper end of the support frame 6, and the upper end of the support frame 6 is also rotatably connected to the pivot 13, and the arc permanent magnet 7 is fixed to the lower end of the support frame 6. The electric push rod 1 is extended and retracted, so that the connecting rod 4 rotates around the rotation center between it and the electric push rod 1, and the angle between the connecting rod 4 and the telescopic rod of the electric push rod 1 is constantly changing, so that the power output direction remains constant. During the rotation of the connecting rod 4, a push-pull force is applied to the swing arm 5, so that the swing arm 5 drives the support frame 6 to rotate around the pivot 13, and the arc-shaped permanent magnet 7 rotates around the pivot 13 together with the support frame 6; the distance between the arc-shaped permanent magnet 7 and the wall is changed by the rotational movement of the arc-shaped permanent magnet 7, and as the position of the arc-shaped permanent magnet 7 is adjusted, the distribution of the magnetic lines of force also changes, thereby changing the adsorption force of the magnetic adsorption device, and realizing the adjustable magnetic adsorption force; the smaller the distance between the arc-shaped permanent magnet 7 and the wall, the greater the magnetic adsorption force; the larger the distance, the smaller the magnetic adsorption force. The ultrasonic sensor 11 is installed on the support frame 6, and is used to measure the distance between its installation position and the wall surface, and then obtain the distance between the magnetic concentration point of the arc-shaped permanent magnet 7 and the wall surface; the pressure sensor 15 is installed between the support frame 6 and the pivot 13, and is used to measure the force applied by the support frame 6 to the pivot 13, and then obtain the actual magnetic adsorption force; the electric push rod 1, the ultrasonic sensor 11 and the pressure sensor 15 are all connected to the control panel 8, and the distance data measured by the ultrasonic sensor 11 and the force data measured by the pressure sensor 15 are transmitted to the control panel 8. After processing and analysis, the control panel 8 controls the electric push rod 1 to extend or shorten, so as to adjust the relative position between the arc-shaped permanent magnet 7 and the wall surface, and then adjust the magnetic adsorption force.

[0048] The electric push rod 1 is also provided with a limit switch 2 and an intelligent machine lock 3. The limit switch 2 is used to limit the extension and contraction amount of the electric push rod 1, and the intelligent machine lock 3 is used to protect the electric push rod 1 when the power is suddenly cut off.

[0049] The arc-shaped design of the permanent magnet makes the magnetic force lines more concentrated in the middle area of ​​the arc-shaped permanent magnet 7, thereby improving the adsorption capacity of the permanent magnetic adsorption device. The center point of the outer edge of the arc-shaped permanent magnet 7 is the magnetic force concentration point and is recorded as point A. Different from the method of applying force in the normal direction of the magnetic force lines to change the magnitude of the magnetic force, the present invention rotates the arc-shaped permanent magnet 7 so that the force applied by the support frame 6 to the arc-shaped permanent magnet 7 is tangentially distributed with the direction of the magnetic force lines, thereby making the magnetic adsorption force adjustment direction along the tangential direction of the magnetic force lines. Compared with the existing magnetic adsorption force adjustment direction along the direction of the magnetic force lines, this adjustment method has low energy consumption and is easier to adjust; the telescopic movement of the electric push rod 1 is converted into the rotational movement of the swing arm 5 through the push-pull movement of the connecting rod 4. The small push-pull force generated by the connecting rod 4 can generate a large driving torque through the swing arm 5 by means of the lever principle, thereby driving the arc-shaped permanent magnet 7 to rotate, so that the regulation efficiency of the magnetic adsorption force is greatly improved, and the precise control of the magnetic adsorption force can be achieved by controlling the telescopic amount of the electric push rod 1, thereby improving the adjustability of the magnetic adsorption device. The telescopic movement of the electric push rod 1 is transmitted through the connecting rod 4, thereby driving the arc-shaped permanent magnet 7 to rotate, and at the same time, it can ensure that the telescopic direction of the electric push rod 1 always remains vertical, avoiding additional internal force caused by the tilt of the power element.

[0050] The pivot 13 not only provides support for the rotation of the support frame 6, but is also fixedly connected to the frame support arm 9 to form the main support structure of the device. The pivot 13 is mounted on the axle 12 through the sealed bearing 16, which not only ensures the free rotation of the axle 12 and improves the stability of the rotation of the axle 12, but also prevents dust or other foreign matter from entering the gap between the axle 12 and the pivot 13, ensures the sealing of the internal lubricating oil, reduces friction, and effectively prolongs the service life of the device, especially maintaining the stable operation of the device in complex environments.

[0051] like Figure 6 As shown, the magnetic adsorption force generated in the initial state is small, and the distance between the magnetic force concentration point A of the arc-shaped permanent magnet 7 and the wall surface is large at this time; the magnitude of the magnetic adsorption force required for the horizontal wall surface, the inclined wall surface and the vertical wall surface gradually increases, and the rotational movement of the arc-shaped permanent magnet 7 is controlled to adjust its position, so that the distance between the magnetic force concentration point A of the arc-shaped permanent magnet 7 and the wall surface gradually decreases. Therefore, the magnetic adsorption force can be dynamically adjusted according to the adsorption requirements of different wall surfaces, thereby achieving a stable adsorption effect and meeting the working requirements of the wall-climbing robot.

[0052] When the wall-climbing robot completes its task, the magnetic adsorption force must be effectively reduced to ensure that the magnetic adsorption device can be safely detached from the wall and avoid damaging the wall. Figure 7As shown, when the magnetic adsorption device enters the disengaged state, the electric push rod 1 extends, causing the arc-shaped permanent magnet 7 to rotate clockwise, thereby gradually increasing the distance between the magnetic force concentration point A of the arc-shaped permanent magnet 7 and the wall surface, thereby reducing the magnetic field strength between the arc-shaped permanent magnet 7 and the wall surface. As the magnetic field strength decreases, the magnetic adsorption force generated by the magnetic adsorption device also decreases until it reaches a critical value for complete separation from the wall surface.

[0053] like Figure 8 As shown, when the wall-climbing robot transitions from a horizontal wall surface to an inclined wall surface, the rotation angle of the arc-shaped permanent magnet 7 is adjusted by the continuous contraction movement of the electric push rod 1, so that the magnetic force concentration point A of the arc-shaped permanent magnet 7 is offset to the inclined wall surface side until the wall-climbing robot completely transitions to the inclined wall surface. For the transition from one wall surface to another, sufficient magnetic adsorption force needs to be ensured.

[0054] The control method of the permanent magnetic adsorption device of the wall-climbing robot with adjustable magnetic force comprises the following contents:

[0055] The force analysis of the wall-climbing robot is carried out on the wall surface to obtain the magnetic force design value F d ; Based on the magnetic design value F d , calculate the standard value d0 of the distance between the magnetic force concentration point A of the arc permanent magnet and the wall surface according to formula (1);

[0056]

[0057] Where k is a constant, which is related to the magnetic properties of the arc permanent magnet and the material properties of the wall;

[0058] Based on the distance between the ultrasonic sensor installation position and the wall, according to the geometric relationship, the distance d between the magnetic force concentration point A of the arc permanent magnet and the wall is obtained; according to the geometric relationship, the relationship between the angular change Δξ of the arc permanent magnet and d and d0 is obtained as follows:

[0059]

[0060] Where, d2 is the distance between the magnetic force concentration point A of the arc-shaped permanent magnet and the pivot axis, and r is the wheel radius;

[0061] like Fig. 9 As shown, assuming that the length of the connecting rod is L2, and the projection length of the connecting rod in the vertical direction in the initial state is L1, the angle β1 between the electric push rod and the connecting rod in the initial state can be expressed as:

[0062]

[0063] In the initial state, the horizontal distance x1 between the connecting rod and the electric push rod satisfies the following formula:

[0064]

[0065] As the electric push rod is extended and retracted, the angle between the electric push rod and the connecting rod, the projection length of the connecting rod in the vertical direction, and the horizontal distance between the connecting rod and the electric push rod will also change. At this time, the angle β2 between the electric push rod and the connecting rod and the horizontal distance x4 between the connecting rod and the electric push rod can be expressed as:

[0066]

[0067] The change in the horizontal distance Δx between the connecting rod and the electric push rod can be expressed as:

[0068] Δx=x1-x4(7)

[0069] The length of the swing arm is d1, the projection length of the swing arm in the horizontal direction in the initial state is x2, and the angle ξ1 between the swing arm and the horizontal direction can be expressed as:

[0070]

[0071] As the electric push rod is extended and retracted, the horizontal projection length of the swing arm and the angle between the swing arm and the horizontal direction change. When the extension amount of the electric push rod is ΔL, the horizontal projection length x3 of the swing arm and the angle ξ2 between the swing arm and the horizontal direction are expressed as:

[0072]

[0073] The angular change Δξ of the arc magnet can be expressed as:

[0074] Δξ=ξ1-ξ2(11)

[0075] The relationship between the angular change Δξ of the arc-shaped permanent magnet and the extension ΔL of the electric push rod is:

[0076]

[0077] Combining equations (2) and (12), we can get the calculation formula for the extension and contraction amount ΔL of the electric push rod:

[0078]

[0079] The relationship between the extension and contraction amount ΔL of the electric push rod and the motor parameters is:

[0080]

[0081] In the formula, n is the motor speed, s is the lead of the electric push rod, t is the motor rotation time, and δ is the reduction ratio of the electric push rod;

[0082] Therefore, it can be seen from formula (14) that by controlling the motor rotation time of the electric push rod, that is, controlling the extension and contraction amount of the electric push rod, the distance between the magnetic concentration point A of the arc permanent magnet and the wall surface reaches the standard distance value d0, thereby realizing precise control of the position of the arc permanent magnet.

[0083] Based on the force applied by the support frame to the arc permanent magnet measured by the pressure sensor, the actual magnetic adsorption force F can be obtained according to the force analysis of the arc permanent magnet. d , the push-pull force variation ΔN of the electric push rod can be obtained as:

[0084]

[0085] Where α1 is the angle between the magnetic adsorption force and the vertical direction, β1 is the angle between the electric push rod and the connecting rod in the initial state, and γ is the angle between the connecting rod and the swing arm in the initial state;

[0086] Therefore, the driving force of the electric push rod is controlled, and then the push-pull force change of the electric push rod is controlled, so that the actual magnetic adsorption force F reaches the magnetic design value F d .

[0087] In summary, by controlling the extension and extension amount and driving force of the electric push rod, the distance between the magnetic force concentration point A of the arc-shaped permanent magnet and the wall surface and the actual magnetic adsorption force are adjusted respectively, so as to realize the coordinated control of the distance and the magnetic adsorption force and ensure the adsorption effect of the magnetic adsorption device. When the distance d between the magnetic force concentration point A of the arc-shaped permanent magnet and the wall surface approaches the standard value d0, and the actual magnetic adsorption force F also approaches the magnetic design value F d When , it indicates that the magnetic adsorption device is in normal working state, and all components move in coordination; if the distance d between the magnetic force concentration point A of the arc permanent magnet and the wall surface does not approach the standard distance value d0, or the actual magnetic adsorption force F does not approach the magnetic force design value F d , it indicates that the magnetic adsorption device is not in normal working condition. You should stop working and find out the cause and eliminate the fault before continuing to work. The actual magnetic adsorption force required by the wall-climbing robot on different wall surfaces (including horizontal wall surfaces, vertical wall surfaces, inclined wall surfaces, wall surface intersection angles and concave and convex wall surfaces) is different. Therefore, the electric push rod is used to control the magnetic adsorption force requirements of the wall-climbing robot on different wall surfaces and when starting and stopping.

[0088] When the push-pull force of the electric linear actuator is greater than or equal to the push-pull force of the electric linear actuator corresponding to the magnetic design value, and the actual magnetic adsorption force is less than the magnetic design value, or when the distance between the magnetic concentration point A of the arc-shaped permanent magnet and the wall surface is less than the standard distance value, and the extension and contraction amount of the electric linear actuator is equal to the extension and contraction amount of the electric linear actuator corresponding to the distance between the magnetic concentration point A of the arc-shaped permanent magnet and the wall surface, it indicates that the device has a stuck fault.

[0089] like Fig.10As shown in the figure, assuming that the driving force generated by the electric push rod is N1, the angle between the electric push rod and the connecting rod in the initial state is β1, and the force N2 exerted by the electric push rod on the connecting rod is:

[0090] N2=N1·cosβ1 (16)

[0091] The torque M1 generated by the connecting rod on the swing arm is expressed as:

[0092] M1=N2·sinγ·d1 (17)

[0093] The actual magnetic attraction force F generated by the arc permanent magnet is expressed as:

[0094]

[0095] The horizontal component of the actual magnetic attraction force F x for:

[0096] F x =F·sinα1 (19)

[0097] The torque M2 generated by the horizontal component of the actual magnetic adsorption force is:

[0098] M2=F·sinα1·d2 (20)

[0099] According to the moment balance, the moment M1 generated by the connecting rod on the swing arm is equal to the moment M2 generated by the horizontal component of the actual magnetic adsorption force, so:

[0100]

[0101] Therefore, the driving force N1 of the electric linear actuator can be expressed as:

[0102]

[0103] In order to achieve the rotation of the arc-shaped permanent magnet through the extension and contraction of the electric push rod, the driving force N1 of the electric push rod must meet the following conditions:

[0104]

[0105] Any matters not described in the present invention are applicable to the prior art.

Claims

1. A permanent magnetic adsorption device for a wall-climbing robot with adjustable magnetic force, characterized in that: The device comprises an electric push rod, a connecting rod, a swing arm, a support frame, an arc-shaped permanent magnet, an ultrasonic sensor, a pivot, a rigid arm and a pressure sensor; the pivot is installed on the axle of the wall-climbing robot and is fixedly connected to the lower end of the support arm of the wall-climbing robot frame; one end of the rigid arm is fixedly connected to the middle part of the support arm of the wall-climbing robot frame, the electric push rod is located at the other end of the rigid arm and the telescopic direction is always along the vertical direction, the telescopic rod end of the electric push rod is rotatably connected to one end of the connecting rod, the other end of the connecting rod is rotatably connected to one end of the swing arm, the other end of the swing arm is fixedly connected to the upper end of the support frame, the upper end of the support frame is rotatably connected to the pivot at the same time, and the arc-shaped permanent magnet is located at the lower end of the support frame; the electric push rod drives the arc-shaped permanent magnet to rotate, adjusts the distance between the arc-shaped permanent magnet and the wall surface, thereby realizing adjustable magnetic adsorption force, and at the same time makes the magnetic adsorption force adjustment direction along the tangent direction of the magnetic force line; The ultrasonic sensor is located on the support frame and is used to measure the distance between the installation position and the wall surface; the pressure sensor is located between the support frame and the pivot and is used to measure the force applied by the support frame to the pivot.

2. The permanent magnetic adsorption device for a wall-climbing robot with adjustable magnetic force according to claim 1, characterized in that: The control method of the device realizes the coordinated control of distance and magnetic adsorption force, including the following contents: The force analysis of the wall-climbing robot is carried out on the wall surface to obtain the magnetic force design value F d , calculate the standard value d0 of the distance between the magnetic force concentration point of the arc-shaped permanent magnet and the wall surface according to formula (1), and the magnetic force concentration point of the arc-shaped permanent magnet is the center point of the outer edge of the arc-shaped permanent magnet; Where k is a constant; Based on the distance data measured by the ultrasonic sensor, according to the geometric relationship, the distance d between the magnetic concentration point of the arc permanent magnet and the wall surface is obtained; according to the geometric relationship, the relationship between the angular change Δξ of the arc permanent magnet and d and d0 can be obtained as follows: Where d2 is the distance between the magnetic force concentration point of the arc-shaped permanent magnet and the pivot axis, and r is the wheel radius; That is, the relationship between the angular change Δξ of the arc-shaped permanent magnet and the extension ΔL of the electric push rod is: Combining equations (2) and (12), we can get the calculation formula for the extension and contraction amount ΔL of the electric push rod: Where, L2 is the length of the connecting rod, L1 is the projection length of the connecting rod in the vertical direction in the initial state, d1 is the length of the swing arm, and x2 is the projection length of the swing arm in the horizontal direction in the initial state; By controlling the rotation time of the electric push rod motor and the extension and contraction amount of the electric push rod, the distance between the magnetic force concentration point of the arc-shaped permanent magnet and the wall surface is made equal to the standard distance value; Based on the force data measured by the pressure sensor, the force analysis of the arc permanent magnet is carried out to obtain the actual magnetic adsorption force F; according to the actual magnetic adsorption force F and the magnetic design value F d , the push-pull force variation ΔN of the electric push rod can be obtained as: Where α1 is the angle between the magnetic adsorption force and the vertical direction, β1 is the angle between the electric push rod and the connecting rod in the initial state, and γ is the angle between the connecting rod and the swing arm in the initial state; By controlling the driving force of the electric push rod, the change in the push and pull force of the electric push rod is controlled so that the actual magnetic adsorption force is equal to the magnetic design value.

3. The permanent magnetic adsorption device for a wall-climbing robot with adjustable magnetic force according to claim 2, characterized in that: To achieve the rotational motion of the arc-shaped permanent magnet, the driving force N1 of the electric push rod must meet the following conditions:

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