A method for controlling electromagnetic force of a magnetically adsorbed cable climbing robot

Abstract

This invention discloses a method for controlling the electromagnetic force of a magnetically adsorbed cable-climbing robot. The method uses the vibration of a bridge cable detection robot on the bridge cable as interference, and uses a posture sensor to detect the robot's motion state. As the magnetically adsorbed robot moves on the inclined cable, if vibration occurs, the posture sensor detects an acceleration signal. This acceleration signal is read by an industrial computer, and the output port voltage is adjusted based on the signal. Finally, a buck boost module is used to amplify the voltage at the industrial computer output port and pass it across the electromagnetic mechanism. A sliding mode control method is used to control the voltage at the industrial computer output port, thereby controlling the current flowing into the electromagnetic mechanism coil. The robot can automatically select the most appropriate electromagnetic force level for control based on the detected vibration signal.

Description

Technical Field

[0001] The present invention relates to the field of robot control technology, and in particular to an electromagnetic force control method for a magnetic adsorption cable climbing robot. Background Art

[0002] Inspecting cables on cable bridges is a crucial task in industrial technology. This type of work, carried out under extremely dangerous conditions, is inefficient, time-consuming, and carries significant risks and challenges if performed manually. The use of magnetic adsorption robots for maintenance not only improves efficiency but also reduces the incidence of maintenance accidents, offering significant benefits to the industrial technology sector.

[0003] The magnetic adsorption robot is a special robot that can perform continuous crawling operations on magnetic conductive surfaces. It can effectively replace humans in performing these dangerous and complicated surface inspection tasks. The magnetic adsorption robot is adsorbed on the cable surface through the adsorption force generated by the magnetic adsorption unit, and the motor drives the robot to climb upward. During the robot's climbing process, factors such as wind force or bulges on the inclined cable surface will cause electromagnetic force fluctuations, causing the robot to fall. The commonly used method at present is PID control, but PID control cannot quickly rise to the required voltage, and the robot is prone to fall during the climbing process. In order to better control the robot, the present invention relates to a new electromagnetic force control method for a magnetic adsorption robot, namely a sliding mode control method in robust control.

[0004] Sliding mode control is a control concept primarily designed for control problems involving unknown disturbances with upper bounds. Broadly speaking, sliding mode control, similar to methods such as H-infinity and disturbance observers, is a form of robust control that enables the control system to maintain certain control performance despite disturbances. From a system dynamics perspective, the key to designing a sliding mode control algorithm lies in:

[0005] 1) For a controlled system exhibiting specific dynamic behavior, how to design a sliding surface or select sliding mode variables (or whether such a sliding surface exists) to ensure that the control system performance (e.g., control error convergence under disturbances) meets expectations;

[0006] 2) How to design the control rate to ensure that the system trajectory starting from the initial state can reach the sliding surface within a finite time, stay within the sliding surface after reaching it, and ensure that the system state variables converge as quickly as possible.

[0007] For magnetic adsorption robots, interference comes from the vibration of the robot affected by many factors. The sliding mode control method of the present invention can effectively keep the robot stable during the maintenance process, thereby achieving the effect of completing the task safely and efficiently. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned existing technologies and to provide an electromagnetic force control method for a magnetic adsorption robot based on sliding mode control of bridge cables, which can timely control the magnitude of the magnetic adsorption force. An electromagnetic mechanism is used to design the adsorption structure. The magnetic force of the electromagnetic mechanism is easy to control, and the value of the magnetic attraction force can be controlled by controlling the magnitude of the current passed into the coil of the electromagnetic mechanism.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0010] A method for controlling electromagnetic force of a magnetically adsorbed cable climbing robot comprises the following steps: Step 1: establishing an electromagnetic force-related model based on the number of coil turns, contact area, current magnitude, and air gap length:

[0011]

[0012] Among them, F dc Indicates the magnitude of electromagnetic force, I indicates the magnitude of current, and N indicates the number of coil turns. is the insurance factor (its value is between 0.05 and 0.15), μ0 is the magnetic permeability of air (its value is 4π×10 -7 H / m), S represents the relative area between the magnetic pole and the inclined cable, and δ represents the average length of the air gap;

[0013] Step 2: The shape of the magnetic pole is an arc. According to the mathematical equations of the curve at the magnetic pole and the curve at the rope, the total length of the air gap is:

[0014]

[0015] in, represents the total length of the air gap, X represents the value of the abscissa in the rectangular coordinate system, Y1 represents the value of the ordinate of the magnetic pole curve in the rectangular coordinate system, R1 represents the radius of curvature of the magnetic pole, Y2 represents the value of the ordinate of the rope curve in the rectangular coordinate system, R2 represents the radius of the rope, and the average length of the air gap in step 1 can be obtained by dividing the total length of the air gap obtained in step 2 by the length of the magnetic pole;

[0016] Step 3: Using the vibration of the magnetic adsorption robot as an interference source, the attitude sensor is used to detect the acceleration change of the magnetic adsorption robot, and the information of the lateral acceleration and longitudinal acceleration is received to detect the shaking state of the magnetic adsorption robot;

[0017] Step 4: Use the industrial computer to read the two acceleration signal values ​​in step 3, process the two values ​​in the industrial computer, and obtain the total acceleration average value |a|; according to the different average values, the shaking level is divided into 10 levels, and the acceleration average value |a| and the output voltage reference value are obtained. The relationship:

[0018]

[0019] The total acceleration average value |a| is compared in real time in the industrial computer to obtain the output voltage reference value

[0020] Step 5: Design the sliding surface s k for:

[0021] s k =mE k +v k

[0022] Among them, m is the parameter to be designed, E k is the voltage tracking gain, v k is the output voltage error integral, and s k >0,v k >0, m>0. Output voltage error integral v k It can be further expressed as:

[0023] v k =v k-1 +GE k-1

[0024] Where G is the integral gain;

[0025] Step 6: According to step 5, the initial state of the system is configured on the sliding surface, and the output voltage error integral v is set k The initial value v0 is:

[0026] v0=-mE0

[0027] Step 7: Design a sliding mode voltage controller and use the discrete equivalent control law:

[0028] s k+1 -s k =0

[0029] Among them, s k+1 To recursively calculate the sliding mode surface of one sampling time step, when the sampling time step is small enough, the output voltage reference value can be considered to remain unchanged within one sampling period:

[0030]

[0031] The sliding mode control law of the Buck circuit is obtained as follows:

[0032]

[0033] in, is the equivalent control sliding film control rate, C is the capacitance value, R is the resistance value, T is the sampling period, uok is the voltage feedback value, f k is the estimated value of the concentrated disturbance;

[0034] In order to enable the system to always reach the quasi-sliding mode, a discontinuous switching control item is added:

[0035]

[0036] in, is an additional switching control item, C is the capacitance value, T is the sampling period K sw is the switching gain, and K sw >0,sgn(s k ) is the sliding surface s k The symbolic function of

[0037] Finally, the complete form of the sliding mode voltage controller is:

[0038]

[0039] Step 8: Introduce the “delayed disturbance estimation” strategy by calculating the concentrated disturbance value mf at the previous sampling moment k To approximate the disturbance at this moment:

[0040]

[0041] Step 9: Output voltage u o Perform real-time sampling and output voltage reference value As one of the input variables, and the real-time output voltage u o Subtract and get E k And f k-1 Input into the formula to get the inductor current reference value

[0042]

[0043] Among them, f k-1 is the estimated value of the concentrated disturbance;

[0044] Step 10, the inductor current i L Perform real-time sampling and compare it with the inductor current reference value Make a difference, perform current inner loop PI control on the difference, and perform PWM on the equivalent duty cycle;

[0045] In step 11, the PWM signal controls the MOSFET in the Buck circuit to obtain an ideal voltage value. The ideal voltage value is output to the DC-DC boost module through the output port of the industrial computer, and finally the voltage is output to both ends of the electromagnetic mechanism to generate a corresponding current, ensuring that the electromagnetic mechanism generates sufficient electromagnetic force to prevent the magnetic adsorption robot from falling under vibration.

[0046] As a further preferred embodiment of the present invention, the mathematical equation of the curve at the magnetic pole obtained according to the curvature radius of the electromagnetic mechanism in step 2 is as follows:

[0047]

[0048] The mathematical equation of the curve at the rope is obtained based on the rope radius as follows:

[0049]

[0050] Wherein, X represents the value of the abscissa of the rectangular coordinate system, Y1 represents the value of the ordinate of the magnetic pole curve in the rectangular coordinate system, R1 represents the radius of curvature of the magnetic pole, Y2 represents the value of the ordinate of the rope curve in the rectangular coordinate system, and R2 represents the radius of the rope.

[0051] Subtract the two equations and integrate them to obtain the mathematical equation for the total length of the air gap in step 2.

[0052] As a further preference of the present invention, in step 5 Among them E k is the voltage tracking gain, u ok is the voltage feedback value, is the output voltage reference value.

[0053] As a further preferred embodiment of the present invention, the posture sensor is arranged on the magnetic adsorption robot. The posture sensor collects information on the lateral acceleration and longitudinal acceleration of the magnetic adsorption robot and transmits a signal to an industrial computer. A DC-DC boost module is connected in series to the output port of the industrial computer. The ideal voltage value is output to the DC-DC boost module through the output port of the industrial computer, and finally the voltage is output to both ends of the electromagnetic mechanism to generate corresponding current.

[0054] As a further preferred embodiment of the present invention, an industrial computer is used as the core control unit to realize automatic current control. Simulink is used as an experimental platform in the industrial computer, and a program is input into the industrial computer using visual programming. The serial receive module in Simulink receives data generated by the posture sensor, processes the data, and uses this data as an input variable for controlling the output voltage reference value. The output voltage reference value is then used in sliding mode control to obtain an ideal output voltage. The ideal output voltage is converted by the industrial computer into a voltage that enables the robot to operate smoothly through a DC-DC boost circuit.

[0055] As a further preference of the present invention, the insurance coefficient is 0.1. According to the actual object, the number of coil turns is 3050, and the relative area between the electromagnetic mechanism and the inclined cable is 1500mm. 2 , taking the air gap δ = 0.2mm, the electromagnetic force is as follows:

[0056] The present invention has the following beneficial effects:

[0057] (1) The robot of the present invention can introduce a "delayed disturbance estimation" strategy based on the detected vibration signal to realize online estimation of the system's centralized disturbance, and integrate the estimation into the robust DISM controller to form compensation, which not only enables the controller to be implemented in engineering, but also further enhances the system output voltage's resistance to load changes and weakens vibration. The control effect of the electromagnetic force can meet the requirements of use.

[0058] (2) For magnetic adsorption robots, interference comes from the vibration of the robot affected by many factors. The sliding mode control method of the present invention can effectively keep the robot stable during the maintenance process, thereby achieving the effect of completing the task safely and efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is the curvature radius in rectangular coordinates;

[0060] Figure 2 is the relationship between the rope radius R2 and the air gap;

[0061] Figure 3 is a curve diagram of electromagnetic force changing with current;

[0062] Figure 4 It is the electromagnetic force control flow chart;

[0063] Figure 5 This is the schematic diagram of the sliding mode control algorithm;

[0064] Figure 6 It is the structure diagram of sliding mode control system;

[0065] Figure 7 This is the hardware schematic diagram of the sliding mode control system;

[0066] Figure 8 This is the voltage simulation curve after sliding mode control. DETAILED DESCRIPTION

[0067] The present invention will be further described in detail below with reference to the accompanying drawings and specific preferred embodiments.

[0068] In the description of the present invention, it should be understood that the terms "left side," "right side," "upper," "lower," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Terms such as "first" and "second" do not indicate the importance of components and therefore should not be construed as limitations on the present invention. The specific dimensions used in this embodiment are intended only to illustrate the technical solution and do not limit the scope of protection of the present invention.

[0069] like Figure 1-8 Figure 1 shows a sliding-mode controlled electromagnetic force control method for a magnetic adsorption robot. The robot is a magnetic adsorption robot that needs to be attached to an inclined cable, and the adsorption surface is a curved surface. To ensure that the adsorption wheel is perpendicular to the cable surface, the angle between the wheel arm and the robot body can be adjusted. The electromagnetic adsorption structure provides electromagnetic force, enabling the robot to be stably attached to the inclined cable surface. A drive motor and drive wheels provide power for the robot's movement.

[0070] The present invention utilizes the function of the lifting electromagnetic mechanism, which is placed at the bottom of the robot and connected to the robot. The inclined cable is made of ferromagnetic material. When the electromagnetic wire is energized, it generates electromagnetic force that attracts the robot and the inclined cable together, achieving the purpose of adsorption, allowing the robot to be stably attached to the inclined cable surface.

[0071] A magnetic robot attaches to an inclined cable using electromagnetic force. Controlling the electromagnetic force is crucial for controlling the robot's motion on the cable. Therefore, mathematical modeling of the electromagnetic force is necessary for the designed electromagnetic structure.

[0072] Maxwell's equations are the most basic equations in electromagnetism. Maxwell's electromagnetic force formula is used to establish a mathematical model of electromagnetic force. After deduction, the following formula can be obtained:

[0073]

[0074] Formula (1-1) is the electromagnetic force model, where F dc is the magnitude of the electromagnetic force, I is the magnitude of the current, N is the number of coil turns, is the safety factor, whose value ranges between 0.05 and 0.15. μ0 is the magnetic permeability of air and its value is 4π×10 -7 H / m, S is the relative area between the magnetic pole and the inclined cable, and δ is the average air gap length.

[0075] As can be seen from Equation (1-1), the magnitude of the electromagnetic force is related to the current, the number of turns of the coil around the iron core, the contact area between the electromagnetic mechanism and the inclined cable, and the air gap length. Among them, the number of turns of the coil and the relative area between the electromagnetic mechanism and the inclined cable are fixed, while the air gap length is related to the diameter of the inclined cable and the shape of the magnetic pole of the electromagnetic mechanism.

[0076] Next, the relationship between the diameter of the inclined cable and the average air gap is analyzed.

[0077] The length of the electromagnetic mechanism is 50 mm and its radius of curvature is 45 mm. The diameter of the inclined cable ranges from 60 mm to 180 mm. The following Figure 1 right-angled coordinate system is established, Figure 1 where both the horizontal and vertical coordinates are lengths and the unit is mm. The radius of curvature of the magnetic pole is 45 mm. Therefore, when the radius of the cable is greater than 45 mm, both ends of the magnetic pole contact the cable. When the radius of the cable is less than 45 mm, the center of the magnetic pole contacts the cable.

[0078] The shape of the magnetic pole is arc-shaped. Let the value of the abscissa of the right-angled coordinate system be X, the radius of curvature of the magnetic pole be R1, the radius of the rope be R2, the value of the ordinate of the magnetic pole curve in the right-angled coordinate system be Y1, and the value of the ordinate of the rope curve in the right-angled coordinate system be Y2. The mathematical equation of the curve at the magnetic pole is as follows:

[0079]

[0080] The mathematical equation of the curve at the rope is obtained according to the radius of the rope as follows:

[0081]

[0082] Since the length of the air gap is different everywhere, we need to first find out the total length of the air gap. Subtracting the mathematical equation of the curve at the magnetic pole from the mathematical equation of the curve at the rope and then integrating, the total length of the air gap is obtained as:

[0083]

[0084] Dividing the obtained total length of the air gap by the length of the magnetic pole, the average length of the air gap can be obtained. According to the conditions, we know that the radius of curvature of the magnetic pole R1 = 45 mm, and the radius of the rope: 30 mm < R2 < 90 mm. The curve of the average gap between the cable and the robot changing with the radius of the inclined cable is as follows Figure 2 shown.

[0085] From the previous analysis, we get the electromagnetic force model as shown in formula (1-1), taking the insurance coefficient is 0.1. According to the actual object, the number of coil turns is 3050, and the contact area between the electromagnetic mechanism and the inclined cable is 1500mm. 2 The unit of I is A. If the air gap δ = 0.2 mm, the electromagnetic force is as shown in the following formula (3-1):

[0086] The curve of electromagnetic force changing with current is as follows Figure 3 shown.

[0087] However, when the robot is heavy, the voltage at the output port of the industrial computer alone may not provide enough suction force to keep the robot stable on the slope. Therefore, in order to solve the problem of insufficient electromagnetic force, a DC-DC boost circuit can be connected in series with the output port of the industrial computer to increase the maximum voltage and thus increase the electromagnetic force. The electromagnetic force control flow chart is shown in the figure below. Figure 4 The structure diagram of the sliding mode control system is shown in Figure 5 shown.

[0088] During the robot's climbing process, factors such as wind or bulges on the inclined cable surface can cause electromagnetic force fluctuations, resulting in changes in lateral and longitudinal acceleration, which can cause the robot to fall. The attitude sensor, mounted on the magnetic robot, collects information about the robot's lateral and longitudinal accelerations and transmits a signal to an industrial computer. A DC-DC boost module is connected in series to the computer's output port. The desired voltage is then output to the DC-DC boost module, which then outputs the voltage to both ends of the electromagnetic mechanism, generating a corresponding current.

[0089] An industrial computer will be used as the core control unit to achieve automatic control of current. Simulink is used as the experimental platform in the industrial computer, and the program is input into the industrial computer using visual programming. The serialreceive module is used in Simulink to receive the data generated by the attitude sensor. After processing the data, this data is used as the input variable to control the output voltage reference value. The output voltage reference value is then used in sliding mode control to obtain the ideal output voltage. The ideal output voltage is converted by the industrial computer through a DC-DC boost circuit into a voltage that can enable the robot to operate smoothly, so that the robot will not shake or even fall when working on a high-altitude cable. The attitude sensor outputs a signal to the industrial computer, which receives the acceleration information, processes the lateral acceleration and longitudinal acceleration, and obtains the total acceleration average value |a|, where |a| is in m / s. 2 According to the different average acceleration values, the shaking level is divided into 10 levels. Based on the empirical values ​​of multiple tests, the average acceleration value |a| and the output voltage reference value are obtained. The relationship:

[0090]

[0091] The vibration level piecewise function diagram is as follows Figure 6 As shown. By using the relationship between acceleration and voltage, the greater the acceleration, the greater the current and the greater the adsorption force, thus ensuring the stability of the robot. The total acceleration average value |a| is compared in real time in the industrial computer to obtain the output voltage reference value.

[0092] Next, perform sliding mode control and design the sliding surface s k for:

[0093] s k =mE k +v k

[0094] Among them, m is the parameter to be designed, E k is the voltage tracking gain, v k is the output voltage error integral, Among them E k is the voltage tracking gain, u ok is the voltage feedback value, is the output voltage reference value, and s k >0,v k >0, m>0.

[0095] Output voltage error integral v k It can be further expressed as:

[0096] v k =v k-1 +GE k-1

[0097] Where G is the integral gain.

[0098] The initial state of the system is configured on the sliding surface, and the output voltage error integral v is set k The initial value v0 is:

[0099] v0=-mE0

[0100] Design a sliding mode voltage controller and use the discrete equivalent control law:

[0101] s k+1 -s k =0

[0102] Among them, s k+1 is the sliding surface of the forward recursion for one sampling time step.

[0103] When the sampling time step is small enough, that is, when the time interval is almost 0, the output voltage reference value can be considered to remain unchanged within one sampling period:

[0104]

[0105] The sliding mode control law of the Buck circuit is obtained as follows:

[0106]

[0107] Where C is the capacitance value, R is the resistance value, T is the sampling period, u ok is the voltage feedback value, f k is the estimated value of the concentrated disturbance.

[0108] In order to enable the system to always reach the quasi-sliding mode, a discontinuous switching control item is added:

[0109]

[0110] Among them, K sw is the switching gain, and K sw >0,sgn(s k ) is the sliding surface s k The sign function of .

[0111] Finally, the complete form of the sliding mode voltage controller is:

[0112]

[0113] Figure 7 The hardware schematic diagram of the sliding mode control system. The “delayed disturbance estimation” strategy is introduced to calculate the concentrated disturbance value mf at the previous sampling moment. k To approximate the disturbance at this moment, u ok Using voltage sensor sampling, u o(k-1) is the voltage sampling value at the previous moment, i L(k-1) is the inductor current sampling value at the previous moment:

[0114]

[0115] For output voltage u o Perform real-time sampling and output voltage reference value As one of the input variables, and the real-time output voltage u o Subtract and get E k And f k-1 Input into the formula to get the inductor current reference value

[0116]

[0117] Among them, f k-1 is the estimated value of the concentrated disturbance.

[0118] For the inductor current i L Perform real-time sampling and compare it with the inductor current reference value The difference is made, the current inner loop PI control is performed on the difference, and the equivalent duty cycle is PWM.

[0119] The PWM signal controls the MOSFET in the Buck circuit to obtain the ideal voltage value, which is the voltage value at which the robot stably adsorbs on the cable. The ideal voltage value is output to the DC-DC boost module through the output port of the industrial computer. The DC-DC boost module amplifies the voltage value of the output port of the industrial computer and finally outputs the voltage to both ends of the electromagnetic mechanism, generating a corresponding current. This can automatically control the size of the adsorption force and ensure that the electromagnetic mechanism generates sufficient electromagnetic force to prevent the robot from falling in a vibrating state. The sufficient electromagnetic force is greater than the wind and other interference forces during the robot's climbing process, thereby preventing the robot from falling. The voltage simulation curve after sliding mode control is shown in the figure below. Figure 8 As shown, Figure 8 The horizontal axis is time, in seconds; the vertical axis is voltage, in V. The present invention greatly reduces the risk and cost of a magnetic adsorption robot falling from a high altitude, and greatly improves the degree of automation of cable bridge cable detection.

[0120] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the scope of protection of the present invention.

Claims

1. A method for controlling electromagnetic force of a magnetically adsorbed cable climbing robot, characterized by: The following steps are involved: Step 1: Establish an electromagnetic force model based on the number of coil turns, contact area, current size, and air gap length: Among them, F dc Indicates the magnitude of electromagnetic force, I indicates the magnitude of current, and N indicates the number of coil turns. is the safety factor, which is between 0.05 and 0.15, and μ0 is the magnetic permeability of air, which is 4π×10 -7 H / m, S represents the relative area between the magnetic pole and the inclined cable, and δ represents the average length of the air gap; Step 2: The shape of the magnetic pole is an arc. According to the mathematical equations of the curve at the magnetic pole and the curve at the rope, the total length of the air gap is: in, represents the total length of the air gap, X represents the value of the abscissa in the rectangular coordinate system, Y1 represents the value of the ordinate of the magnetic pole curve in the rectangular coordinate system, R1 represents the radius of curvature of the magnetic pole, Y2 represents the value of the ordinate of the rope curve in the rectangular coordinate system, R2 represents the radius of the rope, and the average length of the air gap in step 1 can be obtained by dividing the total length of the air gap obtained in step 2 by the length of the magnetic pole; Step 3: Using the vibration of the magnetic adsorption robot as an interference source, the attitude sensor is used to detect the acceleration change of the magnetic adsorption robot, and the information of the lateral acceleration and longitudinal acceleration is received to detect the shaking state of the magnetic adsorption robot; Step 4: Use the industrial computer to read the two acceleration signal values ​​in step 3, process the two values ​​in the industrial computer, and obtain the total acceleration average value |a|; according to the different average values, the shaking level is divided into 11 levels, and the acceleration average value |a| and the output voltage reference value are obtained. The relationship: The total acceleration average value |a| is compared in real time in the industrial computer to obtain the output voltage reference value Step 5: Design the sliding surface s k for: s k =mE k +v k Among them, m is the parameter to be designed, E k is the voltage tracking gain, v k is the output voltage error integral, and s k >0,v k >0, m>0; Output voltage error integral v k Further expressed as: v k =v k-1 +GE k-1 Where G is the integral gain; Step 6: According to step 5, the initial state of the system is configured on the sliding surface, and the output voltage error integral v is set k The initial value v0 is: v0=-mE0 Step 7: Design a sliding mode voltage controller and use the discrete equivalent control law: s k+1 -s k =0 Among them, s k+1 To recursively calculate the sliding surface of one sampling time step, when the sampling time step is small enough, the output voltage reference value is assumed to remain unchanged within one sampling period: The sliding mode control law of the Buck circuit is obtained as follows: in, is the equivalent control sliding film control rate, C is the capacitance value, R is the resistance value, T is the sampling period, u ok is the voltage feedback value, f k is the estimated value of the concentrated disturbance; In order to enable the system to always reach the quasi-sliding mode, a discontinuous switching control item is added: in, is an additional switching control item, C is the capacitance value, T is the sampling period K sw is the switching gain, and K sw >0,sgn(s k ) is the sliding surface s k The symbolic function of Finally, the complete form of the sliding mode voltage controller is: Step 8: Introduce the "delayed disturbance estimation" strategy by calculating the concentrated disturbance value f at the previous sampling moment k-1 To approximate the disturbance at this moment: Step 9: Output voltage u o Perform real-time sampling and output voltage reference value As one of the input variables, and the real-time output voltage u o Subtract and get E k And f k-1 Input into the formula to get the inductor current reference value Among them, f k-1 is the estimated value of the concentrated disturbance; Step 10, the inductor current i L Perform real-time sampling and compare it with the inductor current reference value Make a difference, perform current inner loop PI control on the difference, and perform PWM on the equivalent duty cycle; In step 11, the PWM signal controls the MOSFET in the Buck circuit to obtain an ideal voltage value. The ideal voltage value is output to the DC-DC boost module through the output port of the industrial computer, and finally the voltage is output to both ends of the electromagnetic mechanism to generate a corresponding current, ensuring that the electromagnetic mechanism generates sufficient electromagnetic force to prevent the magnetic adsorption robot from falling under vibration.

2. The electromagnetic force control method of a magnetic adsorption cable climbing robot according to claim 1, characterized in that: In step 2, the mathematical equation of the curve at the magnetic pole obtained based on the curvature radius of the electromagnetic mechanism is as follows: The mathematical equation of the curve at the rope is obtained based on the rope radius as follows: Wherein, X represents the value of the abscissa of the rectangular coordinate system, Y1 represents the value of the ordinate of the magnetic pole curve in the rectangular coordinate system, R1 represents the radius of curvature of the magnetic pole, Y2 represents the value of the ordinate of the rope curve in the rectangular coordinate system, and R2 represents the radius of the rope. Subtract the two equations and integrate them to obtain the mathematical equation for the total length of the air gap in step 2.

3. The electromagnetic force control method of a magnetic adsorption cable climbing robot according to claim 1, characterized in that: In step 5 Among them E k is the voltage tracking gain, u ok is the voltage feedback value, is the output voltage reference value.

4. The electromagnetic force control method of a magnetic adsorption cable climbing robot according to claim 1, characterized in that: The posture sensor is arranged on the magnetic adsorption robot. The posture sensor collects information on the lateral acceleration and longitudinal acceleration of the magnetic adsorption robot and transmits a signal to the industrial computer. A DC-DC boost module is connected in series to the output port of the industrial computer. The ideal voltage value is output to the DC-DC boost module through the output port of the industrial computer, and finally the voltage is output to both ends of the electromagnetic mechanism to generate corresponding current.

5. The electromagnetic force control method of a magnetic adsorption cable climbing robot according to claim 4, characterized in that: An industrial computer is used as the core control unit to realize automatic control of current; Simulink is used as the experimental platform in the industrial computer, and the program is input into the industrial computer through visual programming. The serial receive module is used in Simulink to receive the data generated by the posture sensor. After processing the data, this data is used as the input variable to control the output voltage reference value. The output voltage reference value is then used in sliding mode control to obtain the ideal output voltage. The ideal output voltage is converted by the industrial computer into a voltage that can enable the robot to operate smoothly through a DC-DC boost circuit.

6. The electromagnetic force control method of a magnetic adsorption cable climbing robot according to claim 1, characterized in that: Take the insurance factor is 0.

1. According to the actual object, the number of coil turns is 3050, and the relative area between the electromagnetic mechanism and the inclined cable is 1500mm. 2 , taking the air gap δ = 0.2mm, the electromagnetic force is as follows:

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