Bridge cable detection robot control method

Abstract

The invention discloses a bridge cable detection robot control method, a bridge cable detection robot comprises an outer regular octagonal prism frame and an inner octagonal reinforcing frame, the top and the bottom of the outer regular octagonal prism frame are respectively provided with a front moving wheel set and a rear moving wheel set, the front moving wheel set comprises four H-shaped swing arms hinged to the outer regular octagonal prism frame, and the rear moving wheel set comprises four H-shaped swing arms hinged to the outer regular octagonal prism frame. A swing arm telescopic rod is hinged between the middle of each H-shaped swing arm and the inner octagonal reinforcing frame. Mecanum wheels are arranged on the sides, away from the hinged ends, of the H-shaped swing arms. The sensor assembly comprises a nine-axis attitude sensor and a pressure sensor for acquiring the pressure of the telescopic rod of the swing arm. The control method comprises the control steps of S1 to S7. The bridge inhaul cable detection robot is provided with a specific posture control algorithm, the stability of the bridge inhaul cable detection robot is greatly enhanced, the bridge inhaul cable detection robot can stably crawl on the inhaul cable in a complex environment, and the safety of the detection process is effectively guaranteed.

Description

Technical Field

[0001] This invention relates to the field of bridge structure inspection technology, and in particular to a control method for a bridge cable inspection robot. Background Technology

[0002] As the core structure of long-span transportation engineering, cable-stayed bridges bear the entire load of the bridge deck through their cables. They are exposed to complex environments such as wind, rain, and vibration for a long time, making them prone to defects such as sheath cracking and wire corrosion. Regular inspection and maintenance are crucial to ensuring bridge safety.

[0003] Cable-climbing robots have become a trend in the industry, with wheeled robots being widely used due to their simple structure and strong load-bearing capacity. However, they are prone to tilting, deviation, and other abnormal postures during crawling due to the spiral protrusions on the cable surface, wind vibration interference, and slippery environments. Early robots even required manual cable pulling to correct their posture, but existing equipment lacks real-time and accurate posture correction capabilities. This not only leads to misalignment of detection images and decreased accuracy of 3D modeling, but also poses risks such as equipment damage and secondary cable damage due to rollover, becoming a core bottleneck restricting the intelligent application of robots. However, traditional manual inspection and cable-climbing robot inspection still have the following problems: 1. Traditional manual inspection relies on winch baskets, which is inefficient and poses serious safety hazards. It takes many people half a day to complete the inspection of a 200-meter cable. 2. In terms of safety, traditional manual inspections using winch-assisted suspended baskets involve inspectors working at heights, facing a significant risk of falling. If the suspended basket malfunctions or is affected by external factors such as strong winds or swaying cables, safety accidents are highly likely to occur. 3. In terms of detection accuracy, existing robot technologies are prone to problems such as image misalignment and decreased accuracy of 3D modeling due to unstable posture control. 4. Existing cable climbing robots are prone to abnormal posture when faced with complex factors such as spiral protrusions on the cable surface, wind vibration interference, and slippery environments, which can lead to unstable operation of the equipment and even accidents such as rolling or falling, resulting in equipment damage. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides a control method for a bridge cable inspection robot, which greatly enhances the stability and inspection efficiency of the robot, enabling it to crawl stably on cables in complex environments and ensuring the safety of the inspection process.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A control method for a bridge cable inspection robot is provided. The bridge cable inspection robot includes an outer regular octagonal prism frame and an inner octagonal reinforcement frame. The outer regular octagonal prism frame and the inner octagonal reinforcement frame are fixedly connected by several connecting rods. The top and bottom of the outer regular octagonal prism frame have front and rear moving wheel sets, respectively. The front and rear moving wheel sets have the same structure. The front moving wheel set includes four H-shaped swing arms hinged to the outer regular octagonal prism frame. Each H-shaped swing arm has a swing arm telescopic rod hinged to its middle section with the inner octagonal reinforcement frame. A Mecanum wheel is provided on the side of the H-shaped swing arm away from the hinge end. The robot also includes a sensor assembly, which includes a nine-axis attitude sensor and a pressure sensor for collecting pressure from the swing arm telescopic rod. The pressure sensor and the nine-axis attitude sensor are electrically connected to a main controller. The nine-axis attitude sensor includes a three-axis gyroscope, a three-axis accelerometer, and a three-axis electronic compass. The control method for the bridge cable inspection robot includes the following steps: S1: Install the bridge cable inspection robot on the cable to be inspected at the initial position. The bridge cable inspection robot starts at the initial position and performs self-check and program initialization. At the same time, set the clamping force threshold, roll angle warning threshold and target roll angle. S2: After the bridge cable inspection robot completes self-inspection and program initialization, the main controller controls the swing arm telescopic rods of the front and rear moving wheel sets to begin tightening inward. Once the clamping force of the swing arm telescopic rods of the front and rear moving wheel sets reaches the clamping force threshold, the main controller controls the swing arm telescopic rods to stop tightening and lock. S3: The bridge cable inspection robot begins to adjust its standard posture to its initial position. The nine-axis posture sensor collects the roll angle adjustment of the bridge cable inspection robot, and the main controller adjusts the front and rear movement wheel sets according to the roll angle adjustment. S4: The bridge cable inspection robot begins to crawl upwards along the cable, and the main controller controls both the front and rear moving wheel sets to rotate forward. S5: During the crawling process, pressure sensors collect the clamping force of each swing arm telescopic rod, and the nine-axis attitude sensor collects the raw attitude angle data of the bridge cable inspection robot. Based on the collected clamping force data and raw attitude angle data, the main controller, combined with a PID control algorithm, controls the bridge cable inspection robot to move to the inspection position to perform the inspection operation; specifically: S51: The main controller calculates the circumferential acceleration, axial acceleration, axial velocity, and circumferential velocity of the bridge cable inspection robot through the original attitude angle data, and adjusts the circumferential acceleration, axial acceleration, axial velocity, and circumferential velocity of the bridge cable inspection robot for control. S52: The angular velocity of the bridge cable inspection robot is collected in real time by the three-axis gyroscope, and the actual attitude angle of the bridge cable inspection robot is calculated by combining the quaternion method. The main controller adjusts the angular velocity of the bridge cable inspection robot by the actual attitude angle. S6: After the bridge cable inspection robot completes the inspection work, the main controller controls the front and rear moving wheel sets to reverse, so that the bridge cable inspection robot can perform a backward operation and return to the initial position. S7: After the bridge cable inspection robot returns to its initial position, remove the bridge cable inspection robot and install it on the next cable. Repeat steps S1-S6 to perform the inspection work on the next cable.

[0006] Furthermore, the outer regular octagonal prism frame is divided into an identical left outer regular octagonal prism frame and a right outer regular octagonal prism frame. The left outer regular octagonal prism frame and the right outer regular octagonal prism frame are hinged at one end, and the other end of the left outer regular octagonal prism frame and the right outer regular octagonal prism frame are connected by an electric locking pin, an electromagnet, or a buckle. The inner octagonal reinforcing frame is divided into a left inner octagonal reinforcing frame and a right octagonal reinforcing frame that cooperate with the outer regular octagonal prism frame.

[0007] Furthermore, the telescopic arm is a force-controlled electric push rod.

[0008] Furthermore, the Mecanum wheel has a roller tilt angle of 45°, and the Mecanum wheel rollers of the front moving wheel set and the rear moving wheel set have opposite tilt directions.

[0009] Furthermore, the telescopic arm of the front moving wheel assembly is set at an angle upward, while the telescopic arm of the front moving wheel assembly is set at an angle downward.

[0010] Furthermore, the outer octagonal prism frame, the inner octagonal reinforcing frame, the connecting rod, and the H-shaped swing arm are all made of carbon fiber.

[0011] Furthermore, step S51 specifically includes: S511: Establish the body coordinate system of the bridge cable inspection robot, with the axis of the cable as the coordinate system. An axis, perpendicular to the cable axis and established in a plane on the cable cross-section. Planar coordinate system; the initial position is set as the origin of the bridge cable inspection robot. ; S512: Calculate the circumferential and axial accelerations of the bridge cable inspection robot on the cable; specifically: Calculate circumferential acceleration : ; In the formula, This refers to the circumferential traction component generated by the front moving wheelset. This refers to the circumferential traction component generated by the rear moving wheelset. Quality inspection robot for bridge cables; Calculate axial acceleration : ; ; In the formula, The axial force along the cable axis is measured by a robot used for detecting bridge cables. The output torque of the hub motors in the front and rear moving wheel sets. The wheel radii of the front and rear moving wheelsets are given. The coefficient of friction between the wheel and the cable. The weight of the bridge cable inspection robot, It is the acceleration due to gravity. The angle between the cable and the horizontal plane; S513: Calculate the axial and circumferential velocities of the bridge cable inspection robot on the cable; specifically: Calculate axial velocity : ; In the formula, This refers to the rotational speed of the hub motor. The radius of the wheel; Calculate circumferential velocity : .

[0012] Furthermore, step S52 specifically includes the following steps: S521: The angular velocity of the bridge cable inspection robot is acquired in real time by a three-axis gyroscope. The quaternion is first updated using differential equations, and then the quaternion is converted into attitude angles. Specifically: The angular velocity of the bridge cable inspection robot is acquired in real time using a three-axis gyroscope. Based on the relationship between the quaternion time derivative and the angular velocity, the quaternion model is updated using quaternion differentiation. The specific quaternion differentiation update model is as follows: ; In the formula, quaternions ,in For the real part, , , It is the imaginary part; To detect the angular components of the rotation of the bridge cable detection robot, , The rotation angle of the bridge cable inspection robot around the rotation axis; The unit vector is the axis of rotation; For the three-axis gyroscope to collect data for the bridge cable inspection robot Axis angular velocity, For the three-axis gyroscope to collect data for the bridge cable inspection robot Axis angular velocity, For the three-axis gyroscope to collect data for the bridge cable inspection robot Axial angular velocity; S522: Numerically integrate the quaternion differential update model from step S511 to obtain the relationship between the quaternion and time. Then, obtain the attitude angles, including pitch angles, by converting the quaternion to an attitude angle model. Roll angle Yaw angle The quaternion attitude angle model is as follows: .

[0013] Furthermore, in step S2, the main controller calculates the clamping force required for each telescopic arm to reach the clamping force threshold. At that time, clamping force threshold The following conditions must be met: ; In the formula, The coefficient of friction between the telescopic boom and the cable is denoted as . The angle between the cable and the horizontal plane.

[0014] The beneficial effects of this invention are as follows: The bridge cable inspection robot of this invention adopts a full carbon fiber frame structure. Inside the cable climbing device, it is equipped with a nine-axis attitude sensor. The nine-axis attitude sensor integrates multiple motion sensors such as a three-axis gyroscope, a three-axis accelerometer, and a three-axis electronic compass. Through an embedded low-power ARM processor, using a quaternion-based three-dimensional algorithm and special data fusion technology, it can acquire the robot's attitude information in three-dimensional space in real time and accurately, including pitch angle, roll angle, and yaw angle. During the climbing process of the bridge cable inspection robot, when the cable tilts due to wind vibration, the nine-axis attitude sensor can quickly capture the changes in the robot's pitch and roll angles and transmit this data to the control system in a timely manner, providing an accurate basis for subsequent attitude adjustments. The bridge cable inspection robot of this invention is equipped with four electrically driven tie rods with force monitoring sensors at both the front and rear. These tie rods play a crucial role in the robot's operation, providing a clamping force along the radial direction of the bridge cable to ensure the robot's stable attachment to the cable and prevent slippage due to external forces. The force monitoring sensors monitor the clamping force applied by each tie rod in real time and feed the data back to the main controller. When the robot climbs to certain specific parts of the cable, and the cable's diameter or surface shape changes, the control system can automatically adjust the extension and retraction length of the electric tie rods based on the force monitoring sensor data, thereby changing the clamping force and ensuring that the robot and the cable maintain a suitable frictional force at all times. The bridge cable inspection robot of this invention features a hub motor at the end of the electric tie rod. This hub motor employs a Mecanum wheel structure, with the roller tilt angle precisely set at 45°, and the rollers of the front and rear wheel sets tilting in opposite directions. This unique design enables the hub motor to provide powerful momentum for climbing along the cable's axis. The special structure of the Mecanum wheel gives the robot the ability to move omnidirectionally on a plane. In cable climbing scenarios, it can better adapt to the complex conditions of the cable surface. Through the coordinated movement of different wheel sets, it effectively overcomes problems such as spiral protrusions and unevenness on the cable surface, ensuring the robot's stable forward movement.

[0015] The bridge cable inspection robot of this invention can shorten the inspection cycle to several weeks or even less, greatly improving inspection efficiency. It can provide timely data support for bridge maintenance and management, and reduce the risk of defects not being detected and treated in time due to long inspection cycles.

[0016] The robot of this invention completely avoids the risks of personnel working at heights. Through advanced attitude stabilization control technology and a reliable mechanical structure, it can stably crawl on cables in complex environments, effectively ensuring the safety of the inspection process. Even in harsh conditions such as strong winds or uneven cable surfaces, the robot's attitude controller can respond quickly to ensure that the robot will not fall or roll over, avoiding threats to the lives of inspection personnel and reducing economic losses caused by equipment failure or accidents. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the operation of the bridge cable inspection robot in this invention; Figure 2 This is a schematic diagram of the overall structure of the bridge cable inspection robot in this invention; Figure 3 A structural diagram showing the outer regular octagonal prism frame and the inner octagonal reinforcing frame; Figure 4 This is a structural schematic diagram of the H-shaped swing arm and the swing arm extension rod.

[0018] The symbols for the main components in the diagram are explained below: 1. External octagonal prism frame; 2. Internal octagonal reinforcing frame; 3. Connecting rod; 4. H-shaped swing arm; 5. Swing arm telescopic rod; 6. Mecanum wheel; 7. Cable. Detailed Implementation

[0019] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0020] like Figure 1 , 2 As shown in Figures 3 and 4, the bridge cable inspection robot includes an outer regular octagonal prism frame 1 and an inner octagonal reinforcing frame 2. The outer regular octagonal prism frame 1 and the inner octagonal reinforcing frame 2 are fixedly connected by several connecting rods 3. The top and bottom of the outer regular octagonal prism frame 1 have front and rear moving wheel sets, respectively. The front and rear moving wheel sets have the same structure. The front moving wheel set includes four H-shaped swing arms 4 hinged to the outer regular octagonal prism frame 1. Each H-shaped swing arm 4 has a swing arm telescopic rod 5 hinged between its middle and the inner octagonal reinforcing frame 2. A Mecanum wheel 6 is provided on the side of the H-shaped swing arm 4 away from the hinge end. The robot also includes a sensor assembly, which includes a nine-axis attitude sensor and a pressure sensor that collects the pressure of the swing arm telescopic rod 5. The pressure sensor and the nine-axis attitude sensor are electrically connected to the main controller. The nine-axis attitude sensor includes a three-axis gyroscope, a three-axis accelerometer, and a three-axis electronic compass. The swing arm telescopic rod 5 is a force-controlled electric push rod. The Mecanum wheel 6 has a roller tilt angle of 45°, and the rollers of the Mecanum wheel 6 in the front moving wheel assembly and the rear moving wheel assembly have opposite tilt directions. The swing arm telescopic rod 5 of the front moving wheel assembly is set diagonally upward, and the swing arm telescopic rod 5 of the front moving wheel assembly is set diagonally downward. The outer regular octagonal prism frame 1, the inner octagonal reinforcing frame 2, the connecting rod 3, and the H-shaped swing arm 4 are all made of carbon fiber.

[0021] The control method for a bridge cable inspection robot includes the following steps: S1: Install the bridge cable inspection robot on the cable to be inspected at the initial position. The bridge cable inspection robot starts at the initial position and performs self-check and program initialization. At the same time, set the clamping force threshold, roll angle warning threshold and target roll angle. S2: After the bridge cable inspection robot completes self-inspection and program initialization, the main controller controls the swing arm telescopic rods 5 of the front and rear moving wheel sets to start tightening inward. After the clamping force of the swing arm telescopic rods 5 of the front and rear moving wheel sets reaches the clamping force threshold, the main controller controls several swing arm telescopic rods 5 to stop tightening and lock. In step S2, the main controller calculates the clamping force required for each telescopic arm to reach the clamping force threshold. At that time, clamping force threshold The following conditions must be met: ; In the formula, The coefficient of friction between the telescopic boom and the cable is denoted as . The angle between the cable and the horizontal plane; S3: The bridge cable inspection robot begins to adjust its standard posture to its initial position. The nine-axis posture sensor collects the roll angle adjustment of the bridge cable inspection robot, and the main controller adjusts the front and rear movement wheel sets according to the roll angle adjustment. S4: The bridge cable inspection robot begins to crawl upwards along the cable, and the main controller controls both the front and rear moving wheel sets to rotate forward. S5: During the crawling process, pressure sensors collect the clamping force of each telescopic arm 5, and the nine-axis attitude sensor collects the raw attitude angle data of the bridge cable inspection robot. Based on the collected clamping force data and raw attitude angle data, the main controller, combined with a PID control algorithm, controls the bridge cable inspection robot to move to the inspection position to perform the inspection operation; specifically: S51: The main controller calculates the circumferential acceleration, axial acceleration, axial velocity, and circumferential velocity of the bridge cable inspection robot through the original attitude angle data, and adjusts the circumferential acceleration, axial acceleration, axial velocity, and circumferential velocity of the bridge cable inspection robot for control. S511: To accurately describe the motion state of the bridge cable inspection robot on the cable, a body coordinate system for the bridge cable inspection robot is established, with the axis of the cable as the reference point. An axis, perpendicular to the cable axis and established in a plane on the cable cross-section. Planar coordinate system; let the position coordinates of the bridge cable inspection robot on the cable be... Let the initial position be the origin of the coordinate system for the bridge cable inspection robot. ; S512: Calculate the circumferential and axial accelerations of the bridge cable inspection robot on the cable; The velocity of the bridge cable inspection robot can be decomposed into axial acceleration. and circumferential acceleration ; Axial acceleration It is related to factors such as the output torque of the hub motor, the mass of the robot, and the friction of the cable surface; Let the output torque of the hub motor in the moving wheel assembly be... The coefficient of friction between the wheel and the cable is According to Newton's second law, the axial acceleration can be obtained; specifically: Calculate circumferential acceleration : ; In the formula, This refers to the circumferential traction component generated by the front moving wheelset. This refers to the circumferential traction component generated by the rear moving wheelset. Quality inspection robot for bridge cables; Circumferential acceleration As calculated above, the circumferential traction force component of the moving wheel assembly determines the motion. Establishing these kinematic formulas provides a foundation for subsequent analysis of the robot's motion state and attitude control. Specifically: Calculate axial acceleration : ; ; In the formula, The axial force along the cable axis is measured by a robot used for detecting bridge cables. The output torque of the hub motors in the front and rear moving wheel sets. The wheel radii of the front and rear moving wheelsets are given. The coefficient of friction between the wheel and the cable. The weight of the bridge cable inspection robot, It is the acceleration due to gravity. The angle between the cable and the horizontal plane; The speed of the bridge cable inspection robot on the cable can be decomposed into axial velocity. and circumferential velocity axial velocity The circumferential speed is determined by the traction force along the cable axis provided by the hub motor. It is determined by the circumferential traction component generated by the front and rear wheel sets; S513: Calculate the axial and circumferential velocities of the bridge cable inspection robot on the cable; Calculate axial velocity : ; In the formula, This refers to the rotational speed of the hub motor; Let the circumferential traction component generated by the front wheel assembly be... The circumferential traction component generated by the rear wheel assembly is The robot's mass is According to Newton's second law The circumferential acceleration can be obtained. Then, regarding the circumferential acceleration By integrating, the circumferential velocity can be obtained. Specifically: Calculate circumferential velocity : ; S52: The angular velocity of the bridge cable inspection robot is collected in real time by the three-axis gyroscope, and the actual attitude angle of the bridge cable inspection robot is calculated by combining the quaternion method. The main controller adjusts the angular velocity of the bridge cable inspection robot by the actual attitude angle. A nine-axis attitude sensor acquires the raw attitude angle data of the bridge cable inspection robot, and calculates the actual pitch, roll, and yaw angles of the robot using the quaternion method; specifically: The attitude data acquired by the nine-axis attitude sensor includes: Axial angular velocity , axial angular velocity , Axial angular velocity , Axial acceleration , Axial acceleration , Axial acceleration , Axial magnetic field strength , Axial magnetic field strength , Axial magnetic field strength ; , and The raw data obtained from measurements by a three-axis gyroscope. , and The raw data measured by the triaxial accelerometer. , and Raw data measured by a three-axis electronic compass; S521: The angular velocity of the bridge cable inspection robot is acquired in real time by a three-axis gyroscope. The quaternion is first updated using differential equations, and then the quaternion is converted into attitude angles. Specifically: The angular velocity of the bridge cable inspection robot is acquired in real time using a three-axis gyroscope. Based on the relationship between the quaternion time derivative and the angular velocity, the quaternion model is updated using quaternion differentiation. The specific quaternion differentiation update model is as follows: ; In the formula, quaternions ,in For the real part, , , It is the imaginary part; To detect the angular components of the rotation of the bridge cable detection robot, , The rotation angle of the bridge cable inspection robot around the rotation axis; The unit vector is the axis of rotation; For the three-axis gyroscope to collect data for the bridge cable inspection robot Axis angular velocity, For the three-axis gyroscope to collect data for the bridge cable inspection robot Axis angular velocity, For the three-axis gyroscope to collect data for the bridge cable inspection robot Axial angular velocity; S522: Numerically integrate the quaternion differential update model from step S511 to obtain the relationship between the quaternions and time (the differential equation in S511 is "continuous-time," while the actual data from the three-axis gyroscope is "discrete-time," for example, collected every 0.01 seconds. Numerical integration, such as Euler integration or Runge-Kutta integration, is needed to transform the continuous differential equation into a discrete "quaternion update at each step," obtaining the quaternions at different times). The attitude angles, including pitch angle, are then obtained through the quaternion-to-attitude angle model. Roll angle Yaw angle The quaternion attitude angle model is as follows: ; The bridge cable inspection robot of this invention uses a PID control algorithm to achieve robot posture adjustment: The PID control algorithm processes system errors through three components: proportional (P), integral (I), and derivative (D), thereby outputting a control quantity that makes the system output as close as possible to the target value; specifically: Let the target roll angle be The actual roll angle is Then the error ; The output control quantity of the PID controller The calculation formula is: ; in, As a proportionality coefficient, when When it increases, The integral coefficient; S6: After the bridge cable inspection robot completes the inspection work, the main controller controls the front and rear moving wheel sets to reverse, so that the bridge cable inspection robot can perform a backward operation and return to the initial position. Specifically: During the backward movement, the main controller does not adjust the bridge cable detection robot posture, but controls the clamping force of several swing arm telescopic rods (5) to adjust the position. At the same time, the main controller controls the robot to prevent it from stalling and falling. S7: After the bridge cable inspection robot returns to its initial position, remove the bridge cable inspection robot and install it on the next cable. Repeat steps S1-S6 to perform the inspection work on the next cable.

[0022] In data processing, data filtering and fusion algorithms can be used to improve data accuracy and stability. The Extended Kalman Filter (EKF) algorithm is used to fuse data from gyroscopes, accelerometers, and electronic compasses. The EKF algorithm estimates and updates the system's state by establishing the system's state equations and observation equations. Specifically: Establish the state equation and observation equation of the main controller to estimate and update the state of the bridge cable inspection robot system; Let the state vector of the main controller be... , For transpose, where For a three-axis gyroscope Zero offset error in the axial direction, For a three-axis gyroscope Zero offset error in the axial direction, For a three-axis gyroscope Zero offset error in the axial direction; Equations of state: ; In the formula, This is the state transition function. This is process noise; The first-order differential equation for the state vector; Observation equation: ; In the formula, For the observation function, To observe noise; The observation vector is shown in the table below; more accurate attitude estimates are obtained by iterating the prediction and update steps of the EKF algorithm.

[0023]

Claims

1. A control method for a bridge cable inspection robot, the bridge cable inspection robot comprising an outer regular octagonal prism frame (1) and an inner octagonal reinforcing frame (2), the outer regular octagonal prism frame (1) and the inner octagonal reinforcing frame (2) being fixedly connected by a plurality of connecting rods (3), the top and bottom of the outer regular octagonal prism frame (1) having a front moving wheel set and a rear moving wheel set respectively, the front moving wheel set and the rear moving wheel set having the same structure, the front moving wheel set comprising four H-shaped swing arms (4) hinged to the outer regular octagonal prism frame (1). Each of the H-shaped swing arms (4) is hinged to the inner octagonal reinforcing frame (2) with a swing arm telescopic rod (5). A Mecanum wheel (6) is provided on the side of the H-shaped swing arm (4) away from the hinge end. The system also includes a sensor assembly, which includes a nine-axis attitude sensor and a pressure sensor for collecting the pressure of the swing arm telescopic rod (5). The pressure sensor and the nine-axis attitude sensor are electrically connected to the main controller. The nine-axis attitude sensor includes a three-axis gyroscope, a three-axis accelerometer, and a three-axis electronic compass. The system is characterized in that... The control method for the bridge cable inspection robot includes the following steps: S1: Install the bridge cable inspection robot on the cable to be inspected at the initial position. The bridge cable inspection robot starts at the initial position and performs self-check and program initialization. At the same time, set the clamping force threshold, roll angle warning threshold and target roll angle. S2: After the bridge cable inspection robot completes self-inspection and program initialization, the main controller controls the swing arm telescopic rod (5) of the front moving wheel group and the rear moving wheel group to start tightening inward. After the clamping force of the swing arm telescopic rod (5) of the front moving wheel group and the rear moving wheel group reaches the clamping force threshold, the main controller controls the swing arm telescopic rod (5) to stop tightening and lock. S3: The bridge cable inspection robot begins to adjust its standard posture to its initial position. The nine-axis posture sensor collects the roll angle adjustment of the bridge cable inspection robot, and the main controller adjusts the front and rear movement wheel sets according to the roll angle adjustment. S4: The bridge cable inspection robot begins to crawl upwards along the cable, and the main controller controls both the front and rear moving wheel sets to rotate forward. S5: During the crawling process, the pressure sensor collects the clamping force of each swing arm telescopic rod (5), and the nine-axis attitude sensor collects the original attitude angle data of the bridge cable inspection robot. Based on the collected clamping force data and original attitude angle data, the main controller, combined with the PID control algorithm, controls the bridge cable inspection robot to move to the inspection position to perform the inspection operation; specifically: S51: The main controller calculates the circumferential acceleration, axial acceleration, axial velocity, and circumferential velocity of the bridge cable inspection robot through the original attitude angle data, and adjusts the circumferential acceleration, axial acceleration, axial velocity, and circumferential velocity of the bridge cable inspection robot for control. S52: The angular velocity of the bridge cable inspection robot is collected in real time by the three-axis gyroscope, and the actual attitude angle of the bridge cable inspection robot is calculated by combining the quaternion method. The main controller adjusts the angular velocity of the bridge cable inspection robot by the actual attitude angle. S6: After the bridge cable inspection robot completes the inspection work, the main controller controls the front and rear moving wheel sets to reverse, so that the bridge cable inspection robot can perform a backward operation and return to the initial position. S7: After the bridge cable inspection robot returns to its initial position, remove the bridge cable inspection robot and install it on the next cable. Repeat steps S1-S6 to perform the inspection work on the next cable.

2. The control method for a bridge cable inspection robot according to claim 1, characterized in that, The outer regular octagonal prism frame (1) is divided into an identical left outer regular octagonal prism frame and a right outer regular octagonal prism frame. The left outer regular octagonal prism frame and the right outer regular octagonal prism frame are hinged at one end, and the other end of the left outer regular octagonal prism frame and the right outer regular octagonal prism frame are connected by an electric locking pin, an electromagnet, or a buckle. The inner octagonal reinforcing frame (2) is divided into a left inner octagonal reinforcing frame and a right octagonal reinforcing frame that cooperate with the outer regular octagonal prism frame (1).

3. The control method for a bridge cable inspection robot according to claim 2, characterized in that, The swing arm telescopic rod (5) is a force-controlled electric push rod.

4. The control method for a bridge cable inspection robot according to claim 3, characterized in that, The Mecanum wheel (6) has a roller tilt angle of 45°, and the Mecanum wheel (6) rollers of the front moving wheel set and the Mecanum wheel (6) rollers of the rear moving wheel set have opposite tilt directions.

5. The control method for a bridge cable inspection robot according to claim 4, characterized in that, The swing arm telescopic rod (5) of the front moving wheel assembly is set obliquely upward, and the swing arm telescopic rod (5) of the front moving wheel assembly is set obliquely downward.

6. The control method for a bridge cable inspection robot according to claim 5, characterized in that, The outer regular octagonal prism frame (1), the inner octagonal reinforcing frame (2), the connecting rod (3) and the H-shaped swing arm (4) are all made of carbon fiber.

7. The control method for a bridge cable inspection robot according to claim 1, characterized in that, Step S51 specifically includes: S511: Establish the body coordinate system of the bridge cable inspection robot, with the axis of the cable as the coordinate system. An axis, perpendicular to the cable axis and established in a plane on the cable cross-section. Planar coordinate system; the initial position is set as the origin of the bridge cable inspection robot. ; S512: Calculate the circumferential and axial accelerations of the bridge cable inspection robot on the cable; specifically: Calculate circumferential acceleration : ； In the formula, This refers to the circumferential traction component generated by the front moving wheelset. This refers to the circumferential traction component generated by the rear moving wheelset. Quality inspection robot for bridge cables; Calculate axial acceleration : ； ； In the formula, The axial force along the cable axis is measured by a robot used for detecting bridge cables. The output torque of the hub motors in the front and rear moving wheel sets. The wheel radii of the front and rear moving wheelsets are given. The coefficient of friction between the wheel and the cable. The weight of the bridge cable inspection robot, It is the acceleration due to gravity. The angle between the cable and the horizontal plane; S513: Calculate the axial and circumferential velocities of the bridge cable inspection robot on the cable; specifically: Calculate axial velocity : ； In the formula, This refers to the rotational speed of the hub motor; Calculate circumferential velocity : 。 8. The control method for a bridge cable inspection robot according to claim 1, characterized in that, Step S52 specifically includes the following steps: S521: The angular velocity of the bridge cable inspection robot is acquired in real time by a three-axis gyroscope. The quaternion is first updated using differential equations, and then the quaternion is converted into attitude angles. Specifically: A three-axis gyroscope is used to collect the angular velocity of the bridge cable inspection robot in real time. The relationship between the quaternion time derivative and the angular velocity is then used to update the quaternion using a quaternion differential update model. The specific quaternion differential update model is as follows: ； In the formula, quaternions ,in For the real part, , , It is the imaginary part; To detect the angular components of the rotation of the bridge cable detection robot, , The rotation angle of the bridge cable inspection robot around the rotation axis; The unit vector is the axis of rotation; For the three-axis gyroscope to collect data for the bridge cable inspection robot Axis angular velocity, For the three-axis gyroscope to collect data for the bridge cable inspection robot Axis angular velocity, For the three-axis gyroscope to collect data for the bridge cable inspection robot Axial angular velocity; S522: Numerically integrate the quaternion differential update model from step S511 to obtain the relationship between the quaternion and time. Then, obtain the attitude angles, including pitch angles, by converting the quaternion to an attitude angle model. Roll angle Yaw angle The quaternion attitude angle model is as follows: 。 9. The control method for a bridge cable inspection robot according to claim 1, characterized in that, In step S2, the main controller calculates the clamping force required for each telescopic arm to reach the clamping force threshold. At that time, clamping force threshold The following conditions must be met: ； In the formula, The coefficient of friction between the telescopic boom and the cable is denoted as . The angle between the cable and the horizontal plane.

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