Flight-wall climbing dual-mode conversion unmanned aerial vehicle and motion control method thereof

Abstract

The application provides a flight-wall climbing dual-mode conversion unmanned aerial vehicle and a motion control method thereof, and relates to the technical field of aircrafts. The unmanned aerial vehicle comprises: a rack, the top of which is provided with a laser radar; a suction mechanism; a plurality of wall climbing mechanisms, comprising a fixed support, a walking wheel, a rotor, a first motor and a second motor; a plurality of mode conversion mechanisms, each of which is connected with a wall climbing mechanism; and a controller, which is used for acquiring target wall features from the laser radar, controlling the second motor to drive the rotor to rotate so that the unmanned aerial vehicle approaches the target wall, controlling the first steering wheel and the second steering wheel to rotate to adjust the posture of the unmanned aerial vehicle, controlling the vacuum pump to adjust the air pressure in the suction cavity so that the suction cavity is adsorbed to the target wall, and controlling the first motor to drive the walking wheel to move on the target wall. The application has the beneficial effect that the unmanned aerial vehicle can be smoothly and efficiently switched between the flight mode and the wall climbing mode, and the unmanned aerial vehicle can be smoothly transitioned to the wall and kept stably attached.

Description

Technical Field

[0001] This invention relates to the field of aircraft technology, and in particular to a flight-climbing dual-mode switching unmanned aerial vehicle and its motion control method. Background Technology

[0002] Currently, multi-rotor drones are widely used in diverse mission scenarios such as aerial inspection and environmental monitoring due to their flexible control performance and relatively convenient deployment. However, due to the inherent constraints of their flight characteristics, multi-rotor drones can only perform tasks in a three-dimensional aerial environment. They have significant limitations in special operating scenarios such as vertical walls and complex terrains. Specifically, they cannot operate on these special surfaces and simultaneously face the dual technical bottlenecks of insufficient flight performance and climbing ability.

[0003] To effectively overcome the aforementioned technical challenges, some cutting-edge research has proposed innovative solutions, namely, deeply integrating adhesion technology with the flight control system of quadcopter drones. This aims to achieve stable adhesion of the drone to special surfaces such as walls, while simultaneously ensuring precise motion control. This technological integration provides new ideas and possibilities for expanding the application boundaries of quadcopter drones. However, although the technology combining adhesion and flight control has significant application potential, in practical applications, how to achieve smooth and efficient switching between flight modes and wall-climbing modes, while ensuring that the drone's flight trajectory remains smooth and collisions are avoided during mode transitions, remains a key technical challenge that urgently needs to be overcome. Summary of the Invention

[0004] In view of this, in order to solve the problem of stable attachment of UAVs to special surfaces such as walls, while ensuring that they can perform precise motion control, embodiments of the present invention provide a flight-wall-climbing dual-mode UAV and its motion control method.

[0005] Embodiments of the present invention provide a flight-wall-climbing dual-mode switching unmanned aerial vehicle, comprising:

[0006] The rack has a lidar sensor mounted on top.

[0007] An adsorption mechanism is located at the bottom of the frame. The adsorption mechanism includes an adsorption chamber, a vacuum pump, and a pressure sensor. The vacuum pump is connected to the adsorption chamber. The lower end of the adsorption chamber is provided with a soft skirt. The pressure sensor is located in the adsorption chamber to detect the gas pressure in the adsorption chamber.

[0008] Multiple wall-climbing mechanisms include a fixed bracket, wheels, rotors, a first motor, and a second motor, wherein the wheels are rotatably mounted on the fixed bracket, the first motor is connected to the wheels to drive them to rotate, the rotors are mounted inside the wheels, and the second motor is connected to the rotors to drive them to rotate.

[0009] Multiple modal conversion mechanisms are provided, each of which is spaced apart around the frame. Each modal conversion mechanism is connected to a wall-climbing mechanism. Each modal conversion mechanism includes a first servo motor and a second servo motor. The first servo motor is fixedly mounted on the frame and its output end is connected to the second servo motor. The output end of the second servo motor is connected to a fixed bracket. The first servo motor and the second servo motor are used to drive the wall-climbing mechanism to rotate around two mutually perpendicular rotation axes.

[0010] The system includes a controller connected to the lidar, the vacuum pump, the pressure sensor, the first motor, the second motor, the first servo motor, and the second servo motor. The controller is used to acquire target wall features from the lidar, control the second motor to drive the rotor to rotate so that the UAV approaches the target wall, control the first and second servo motors to rotate to adjust the UAV's attitude, and control the vacuum pump to adjust the air pressure in the adsorption chamber so that the adsorption chamber adsorbs onto the target wall. The controller also controls the first motor to drive the wheels to move on the target wall.

[0011] Furthermore, the adsorption cavity includes a fixed plate, a sealing cover, and a movable plate, wherein the fixed plate is fixed to the bottom of the frame, the sealing cover is a multi-layered folded cavity structure, the upper end of the sealing cover is connected to the fixed plate, the lower end of the sealing cover is connected to the movable plate, and the upper end of the soft skirt is connected to the movable plate and is arranged around the movable plate.

[0012] Furthermore, the traveling wheel includes a hub, the hub includes an outer ring, an inner ring, and a plurality of connecting plates connecting the outer ring and the inner ring. The second motor is installed inside the inner ring, and the rotor is located on the front side of the inner ring and connected to the second motor.

[0013] Furthermore, the front edge of the outer ring of the wheel hub is provided with a protective cover that extends forward. The protective cover has a hollow structure, and the rotor is located inside the protective cover.

[0014] Furthermore, the rotor includes two helical blades and a blade support, with one end of each helical blade overlapping and fixed to the blade support, and the blade support connected to the second motor.

[0015] Furthermore, the first motor is connected to the walking wheel via a gear set, the gear set including a driving gear and a driven gear, the driving gear being rotatably mounted on the fixed bracket, the driven gear being sleeved on the inner ring of the wheel hub, the driving gear and the driven gear meshing, and the first motor being connected to the driving gear.

[0016] Furthermore, the top of the frame is provided with an upwardly extending radar bracket, on which the lidar is mounted.

[0017] Furthermore, the frame is rectangular, and there are four wall-crawling mechanisms, which are respectively located at the four corners of the frame.

[0018] Furthermore, embodiments of the present invention also provide a motion control method for a flight-wall-climbing dual-mode conversion UAV, applied to the aforementioned flight-wall-climbing dual-mode conversion UAV, and including the following steps:

[0019] S1. Obtain target wall features and current status information of the UAV through lidar;

[0020] S2. Establish a mode transition dynamics model by combining the target wall features and the current state information of the UAV;

[0021] S3. Using the mode transition dynamics model as a constraint and minimizing the state tracking error and control cost as the objective, a cost function is constructed. The gradient method is used to solve the cost function online to obtain the optimal adsorption force adjustment curve and the optimal trajectory control command.

[0022] S4. Control the input of the second motor of each wall-climbing mechanism according to the optimal trajectory control command, drive the rotor to rotate, and bring the UAV close to the target wall. Control the vacuum pump according to the adsorption force adjustment curve to adjust the magnitude of the adsorption force, so that the adsorption mechanism adsorbs onto the target wall. Control the first servo and the second servo of each mode conversion mechanism to rotate, so that each walking wheel contacts the target wall, thereby converting the UAV from flight mode to wall-climbing mode.

[0023] S5. In wall-climbing mode, control the first motor to drive the walking wheels to rotate and the vacuum pump to adjust the magnitude of the adsorption force, and coordinate the control of the propulsion force and adsorption force to make the walking wheels move on the wall surface.

[0024] Furthermore, the mode transition dynamics model in step S2 includes the dynamic equations in flight mode and the dynamic equations in wall-climbing mode;

[0025] The dynamic equations in flight mode are:

[0026]

[0027] Where M(q) is the mass matrix. Let G(q) be the Coriolis force matrix, G(q) be the gravity term, τ be the external disturbance torque, and u be the control input.

[0028] The dynamic equations in the wall-climbing mode are:

[0029]

[0030] Among them, F adhesion It is adsorption force, and the expression for adsorption force is:

[0031] F adhesion =k adhesion ·p

[0032] Where, k adhesion is the adsorption force coefficient, and p is the gas pressure inside the adsorption chamber;

[0033] The cost function in step S3 is:

[0034]

[0035] Where α and β are weighting coefficients, q state (t) represents the state variable of the UAV.

[0036] q ref (t) represents the desired state, and u(t) represents the control input;

[0037] The control input for the optimal trajectory control command is determined using the following method:

[0038] Design a mode transition function λ(t) whose value smoothly transitions between flight mode and wall-climbing mode:

[0039]

[0040] Among them, T transition It is the duration of the mode transition;

[0041] The control input is:

[0042] u(t)=λ(t)·u flight (t)+(1-λ(t))·u adhesion (t)

[0043] Among them, U flight (t) represents the control input in flight mode, U adhesion (t) is the adsorption force control input.

[0044] The beneficial effects of the technical solutions provided by the embodiments of the present invention are as follows:

[0045] 1. The present invention provides a flight-wall-climbing dual-mode conversion UAV, which has a flight mode and a wall-climbing mode. In flight mode, each wall-climbing mechanism generally maintains a horizontal state, and the rotor is driven to rotate by a second motor, enabling the UAV to fly stably to the target wall. When it is necessary to switch to the wall-climbing mode, the adsorption mechanism extracts negative pressure inside the sealed cover through a vacuum pump, causing the soft skirt to adhere tightly to the target wall. The mode conversion mechanism drives each wall-climbing mechanism to tilt, and the walking wheels of the wall-climbing mechanism contact the target wall, achieving a stable and reliable adsorption effect on complex curved surfaces. In wall-climbing mode, while the adsorption mechanism successfully contacts the target wall, each wall-climbing mechanism can also drive the walking wheels through a first motor, enabling it to move flexibly on the target wall, thereby achieving attitude adjustment of the UAV and realizing a smooth and efficient switching between flight mode and wall-climbing mode.

[0046] 2. The present invention provides a motion control method for a flight-wall-climbing dual-mode conversion UAV. During the transition from flight mode to wall-climbing mode, a laser radar is used to acquire target wall features and relative attitude information of the UAV. Combined with the UAV's dynamic model and adsorption characteristics, a mode-conversion dynamic model is constructed. A model predictive control method is used to calculate the optimal adsorption force adjustment curve and the optimal trajectory control command in real time. During the contact between the UAV and the target wall, the rotor of the wall-climbing mechanism is controlled to rotate according to the optimal trajectory control command to bring the UAV closer to the target wall. At the same time, the magnitude of the adsorption force is precisely adjusted according to the optimal adsorption force adjustment curve. Based on the relative position and speed of the UAV and the wall, the target value of the adsorption force is calculated in real time to ensure that the UAV can smoothly transition to the wall and maintain stable adhesion. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of a flight-wall-climbing dual-mode conversion unmanned aerial vehicle (UAV) according to the present invention;

[0048] Figure 2 This is a schematic diagram of a flight mode of a dual-mode switching UAV for flying and climbing according to the present invention;

[0049] Figure 3 This is a schematic diagram of the adsorption mechanism;

[0050] Figure 4 This is the first schematic diagram of a wall-crawling mechanism;

[0051] Figure 5 This is a second schematic diagram of the wall-crawling mechanism;

[0052] Figure 6 This is a schematic diagram of the mode conversion mechanism;

[0053] Figure 7 This is a schematic diagram illustrating the process by which a dual-mode conversion UAV for flight and wall climbing of the present invention switches from flight mode to wall climbing mode;

[0054] Figure 8 This is a schematic diagram of a dual-mode switching (flight-climbing) drone climbing mode according to the present invention.

[0055] In the diagram: 1. Frame; 101. Radar bracket; 102. LiDAR; 2. Adsorption mechanism; 201. Vacuum pump; 202. Fixing plate; 203. Sealing cover; 204. Movable plate; 205. Soft skirt; 206. Support column; 3. Wall crawling mechanism; 301. Outer ring of hub; 302. Inner ring of hub; 303. Connecting plate; 304. Spiral blade; 305. Blade bracket; 306. Support plate; 307. First motor; 308. Second motor; 309. Protective cover; 310. Hole; 311. Drive gear; 312. Driven gear; 4. Mode conversion mechanism; 401. First servo motor; 402. Second servo motor; 403. Servo motor bracket. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described below with reference to the accompanying drawings. The following description presents a preferred embodiment of the various possible embodiments of the present invention, intended to provide a basic understanding of the invention, but not intended to identify key or decisive elements of the invention or to limit the scope of protection sought.

[0057] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0058] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0059] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures. Also, it should be understood that, for ease of description, the dimensions of the various parts shown in the figures are not drawn to actual scale.

[0060] It should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] Please refer to Figure 1 and Figure 2 The present invention provides a flight-wall-climbing dual-mode conversion unmanned aerial vehicle, including a frame 1, an adsorption mechanism 2, multiple wall-climbing mechanisms 3, a mode conversion mechanism 4, and a controller.

[0062] The frame 1 is a mounting platform, and a lidar 102 is mounted on its top. The lidar 102 is used to obtain information about the target wall features and the current status of the UAV. The wall features include the position and angle of the wall and the relative position between the UAV and the wall.

[0063] The shape of the frame 1 can be flexibly selected according to the actual application scenario. For example, in this embodiment, the frame 1 is rectangular, specifically a rectangular frame structure. The top of the frame 1 is provided with an upwardly extending radar bracket 101, and the lidar 102 is installed on the radar bracket.

[0064] Please refer to Figure 3 The adsorption mechanism 2 is located at the bottom of the frame 1. The adsorption mechanism 2 mainly includes an adsorption chamber, a vacuum pump 201 and a pressure sensor. The vacuum pump 201 is connected to the adsorption chamber. The lower end of the adsorption chamber is provided with a soft skirt 205. The pressure sensor is located in the adsorption chamber to detect the air pressure in the adsorption chamber.

[0065] The adsorption chamber includes a fixed plate 202, a sealing cover 203, and a movable plate 204. The fixed plate 202 is fixed to the bottom surface of the frame 1. Multiple support columns 206 are provided on the fixed plate 202, and the upper end of each support column 206 is fixedly connected to the bottom surface of the frame 1. The vacuum pump 201 is mounted on the fixed plate 202 and communicates with the interior of the sealing cover 203. The upper end of the sealing cover 203 is connected to the fixed plate 202, and the lower end is connected to the movable plate 204. The upper end of the soft skirt 205 is connected to the movable plate 204 and surrounds the movable plate 204.

[0066] The soft skirt 205 is generally a rubber skirt. The vacuum pump 201 can draw negative pressure inside the sealing cover 203 to make the soft skirt 205 contact and adhere to the surface of the object being tested. When the surface of the object being tested is curved or other undulating, the soft skirt 205 can adapt to the shape of the surface of the object being tested, thereby stably contacting and adhering to the surface of the object being tested.

[0067] In some embodiments, the sealing cover 203 is a multi-layered folded cavity structure. Thus, when the vacuum pump 201 draws negative pressure into the sealing cover 203, the sealing cover 203 can be folded, reducing its length and thus allowing for more stable contact and adsorption with the surface of the object being tested.

[0068] Please refer to Figure 4 and Figure 5 The wall crawling mechanism 3 is generally configured as multiple, and each modal conversion mechanism 4 is arranged at intervals around the frame 1, with each modal conversion mechanism 4 connected to one wall crawling mechanism 3.

[0069] Each of the wall-climbing mechanisms 3 includes a fixed bracket, a walking wheel, a rotor, a first motor 307, and a second motor 308. The walking wheel is rotatably mounted on the fixed bracket. The first motor 307 is connected to the walking wheel to drive the walking wheel to rotate. The rotor is installed inside the walking wheel. The second motor 308 is connected to the rotor to drive the rotor to rotate.

[0070] Specifically, the traveling wheel includes a hub, which includes an outer hub ring 301, an inner hub ring 302, and multiple connecting plates 303 connecting the outer hub ring 301 and the inner hub ring 302. The outer hub ring 301 and the inner hub ring 302 are coaxially arranged. The number of connecting plates 303 is generally three or more, as in this embodiment, the number of connecting plates 303 is three. Each connecting plate 303 is generally evenly spaced around the inner hub ring 302. The second motor 308 is installed inside the inner hub ring 302, and the rotor is located on the front side of the inner hub ring 302 and connected to the second motor 308. Both the first motor 307 and the second motor 308 can be selected as motors, and the rotation of the hub and the rotor is controlled by controlling the rotation of the motors.

[0071] In some embodiments, the first motor 307 is connected to the walking wheel via a gear set, the gear set including a driving gear 311 and a driven gear 312, the driving gear 311 being rotatably mounted on the fixed bracket, the driven gear 312 being sleeved on the inner ring 302 of the wheel hub, the driving gear 311 and the driven gear 312 meshing, and the first motor 307 being connected to the driving gear 311.

[0072] The rotor can be flexibly selected from various UAV rotors according to actual applications. In some embodiments, the rotor includes two helical blades 304 and a blade support 305, one end of the two helical blades 304 overlaps and is fixed on the blade support 305, and the blade support 305 is connected to the second motor 308.

[0073] In some embodiments, the front edge of the outer ring 301 of the hub is further provided with a forward-extending protective cover 309, and the rotor is located inside the protective cover 309. The protective cover 309 is arranged circumferentially around the outer ring 301 of the hub, and the rotation diameter of the rotor is smaller than the inner diameter of the protective cover 309. In order to facilitate smoother airflow when the rotor rotates, the protective cover 309 has a hollow structure, such as a ring of hollow holes 310 on the side wall of the protective cover 309, to accelerate airflow.

[0074] Please refer to Figure 6 and Figure 8 Each of the modal conversion mechanisms 4 is spaced apart around the frame 1. Each modal conversion mechanism 4 is connected to a wall-crawling mechanism 3. Each modal conversion mechanism 4 includes a first servo motor 401 and a second servo motor 402. The first servo motor 401 is fixedly installed on the frame 1 and its output end is connected to the second servo motor 402. The output end of the second servo motor 402 is connected to a fixed bracket. The first servo motor 401 and the second servo motor 402 are used to drive the wall-crawling mechanism 3 to rotate around two mutually perpendicular rotation axes so that the walking wheel can walk on the curved surface.

[0075] Specifically, the first servo 401 is a single-axis servo, and the second servo 402 is a dual-axis servo. The single-axis servo is fixedly mounted on the servo bracket 403. The output shaft of the single-axis servo is arranged along the front-rear direction, extends out of the servo bracket 403, and connects to the dual-axis servo. The fixed bracket includes two support plates 306 arranged opposite each other. The two output shafts of the dual-axis servo extend to the left and right respectively, and are respectively connected to one end of the two support plates 306. The two output shafts of the dual-axis servo synchronously drive the two support plates 306 to rotate. The other end of the two support plates 306 is connected to the rear end of the inner ring 302 of the wheel hub, thereby connecting to the running wheel.

[0076] It should be noted that the number of the wall-climbing mechanisms 3 can be flexibly set according to the walking needs of the frame 1. In this embodiment, for example, there are four wall-climbing mechanisms 3, which are respectively arranged at the four corners of the frame 1.

[0077] Please refer to Figure 7The controller is installed inside the frame 1 and is connected to the lidar 102, the vacuum pump 201, the pressure sensor, the first motor 307, the second motor 308, the first servo motor 401, and the second servo motor 402. The controller is used to obtain target wall features from the lidar 102, control the second motor 308 to drive the rotor to rotate so that the UAV approaches the target wall, control the first servo motor 401 and the second servo motor 402 to rotate and adjust the attitude of the UAV, control the vacuum pump 201 to adjust the air pressure in the adsorption chamber so that the adsorption chamber adsorbs with the target wall, and control the first motor 307 to drive the wheels to move on the target wall.

[0078] This invention discloses a dual-mode flying / wall-climbing unmanned aerial vehicle (UAV) with a flight mode and a wall-climbing mode. In flight mode, each wall-climbing mechanism 3 generally remains horizontal, and the rotor is driven to rotate by the second motor 308, enabling the UAV to fly stably to the target wall. When switching to wall-climbing mode, the adsorption mechanism 2 uses a vacuum pump 201 to extract negative pressure inside the sealed cover, causing the soft skirt to adhere tightly to the target wall. The mode-switching mechanism drives the wheels of each wall-climbing mechanism 3 to tilt and contact the target wall, achieving a stable and reliable adsorption effect on complex curved surfaces. In wall-climbing mode, while the adsorption mechanism 2 successfully contacts the target wall, each wall-climbing mechanism 3 can also drive the wheels through the first motor 307, allowing it to move flexibly on the target wall, thereby achieving attitude adjustment of the UAV. This enables the UAV to switch smoothly and efficiently between flight mode and wall-climbing mode.

[0079] In addition, the exam Figure 7 The embodiments of the present invention also provide a motion control method for a flight-wall-climbing dual-mode conversion UAV, applied to the aforementioned flight-wall-climbing dual-mode conversion UAV, and including the following steps:

[0080] S1. Obtain target wall features and current status information of the UAV through lidar 102.

[0081] First, the UAV flies to a preset range near the target wall in flight mode. Then, in flight mode, the UAV uses TMINCO (Timed Minimum Control Force Method) to generate the optimal quadcopter flight trajectory. This method utilizes the differential flatness characteristic of multi-rotor systems, greatly simplifying the trajectory optimization model by mapping translational motion to a single flat output space. The specific method is as follows:

[0082] First, define a flat output function y(t), which represents the deviation of the UAV trajectory:

[0083] y(t)=q(t)-q0(t)

[0084] Where q0(t) is the target trajectory, and q(t) is the actual trajectory. The relationship between the control input and the trajectory can be expressed as:

[0085]

[0086] The formula derives the required control input through dynamic equations and constraints. The control input is the magnitude of the lift generated by the rotor, and the input is adjusted by controlling the second motor 308.

[0087] The objective function is as follows: Minimize the total change in control input by optimizing the objective, thereby reducing energy consumption and smoothing the trajectory.

[0088]

[0089] The objective function requires minimizing the change in the control input over a given time interval.

[0090] During actual drone flight, a set of time intervals and intermediate waypoints are first selected to discretize the entire trajectory into multiple segments. Within each segment, the drone's flat output function is expressed as a high-order polynomial using the method described above, and the analytical relationship between the polynomial coefficients and the control input is solved based on the dynamic model. Next, by minimizing the rate of change of the control input along the entire trajectory, a convex quadratic programming problem is constructed to solve for the optimal polynomial coefficients.

[0091] After obtaining the flat output polynomial, the state and control variables of the UAV, such as position, velocity, acceleration, and angular velocity, can be easily solved. Compared with traditional trajectory optimization methods, TMINCO avoids a large amount of numerical integration and iterative computation, generates smooth trajectories with continuous acceleration, and can fully consider the dynamic constraints of the UAV, making it very suitable for real-time applications.

[0092] In this way, the UAV can quickly generate the optimal trajectory from the starting point to the destination based on the waypoint sequence of the global trajectory planning; on the other hand, it can adjust the local trajectory in real time to cope with environmental interference, such as obstacle avoidance and wind disturbance.

[0093] During the drone's flight, the lidar 102 continuously scans the area ahead. Once it reaches a preset range near the target wall, it acquires the target wall features and the drone's current status information, and sends these information to the controller. The wall features include the wall's position, angle, and the relative position of the drone to the wall. The drone's current status information includes its position, speed, and attitude.

[0094] S2. Establish a mode transition dynamics model by combining the target wall features and the current state information of the UAV.

[0095] The mode conversion dynamics model in step S2 includes the dynamic equations in flight mode and the dynamic equations in wall climbing mode;

[0096] The dynamic equations in flight mode are:

[0097]

[0098] Where M(q) is the mass matrix, representing the inertial characteristics of the UAV;

[0099] The Coriolis force matrix includes the rotational inertia of the UAV and the effects of external forces.

[0100] G(q) is the gravity term, representing the effect of gravity on the drone;

[0101] τ is the external disturbance torque, representing wind or other external disturbances;

[0102] u is a control input, representing the thrust generated by the second motor 308 driving the rotor to rotate;

[0103] In wall-climbing mode, in addition to the flight control inputs, the effect of adhesion forces must also be considered. Therefore, the dynamic equations for wall-climbing mode are:

[0104]

[0105] Where F adhesion Adsorption force is expressed as:

[0106] F adhesion =k adhesion ·p

[0107] in:

[0108] k adhesion Adhesion coefficient: indicates the adhesion properties of a material.

[0109] p: The air pressure inside the adsorption chamber, representing the driving source of the adsorption force.

[0110] S3. Using the mode transition dynamics model as a constraint and minimizing the state tracking error and control cost as the objective, a cost function is constructed. The gradient method is used to solve the cost function online to obtain the optimal adsorption force adjustment curve and the optimal trajectory control command.

[0111] This section first optimizes the timing of the drone's transition from flight mode to wall-climbing mode. A cost function is defined to minimize the changes in control input and adhesion force during the switching process. The cost function is used to evaluate the deviation between the control input and the state variables.

[0112] The cost function is:

[0113] J=∫0 T (α·||q state (t)-q ref (t)|| 2 +β·||u(t)|| 2 )dt

[0114] Where α and β are weighting coefficients used to balance the weights of state error and control input;

[0115] q state (t) represents the state variable of the UAV;

[0116] q ref (t) represents the desired state;

[0117] u(t) represents the control input.

[0118] When switching between flight mode and wall-climbing mode, the control input needs to transition smoothly to avoid instability.

[0119] The control input for the optimal trajectory control command when the drone switches from flight mode to wall-climbing mode is determined according to the following method:

[0120] Design a mode transition function λ(t) whose value smoothly transitions between flight mode and wall-climbing mode:

[0121]

[0122] Among them, T transition It is the duration of the mode transition.

[0123] The control input is:

[0124] u(t) = λ(t)·u fight (t)+(1-λ(t))·u adhesion (t)

[0125] Among them, U flight (t) represents the control input in flight mode, U adhesion (t) is the adsorption force control input.

[0126] During the transition from flight mode to wall-climbing mode, this control input gradually reduces the drone's speed in flight mode and increases its suction force, ultimately completing the wall-climbing switch. This ensures a smooth transition of control input during mode transitions, avoiding instability caused by abrupt changes.

[0127] To ensure a smooth transition to the wall-climbing mode, kinematic and dynamic constraints are used to limit abrupt changes in control inputs during the transition, and linear interpolation is employed to smooth the transition speed and adhesion force.

[0128] Furthermore, a gradient optimization algorithm is used to adjust the control input in real time to ensure the optimality of the trajectory in the dynamic environment. The gradient descent method is used to update the control input to approximate the optimal trajectory, thereby obtaining the optimal adsorption force adjustment curve and the optimal trajectory control command.

[0129] S4. According to the optimal trajectory control command, control the input of the second motor 308 of each of the wall climbing mechanisms 3 to drive the rotor to rotate, so that the UAV approaches the target wall. According to the adsorption force adjustment curve, control the vacuum pump 201 to adjust the magnitude of the adsorption force, so that the adsorption mechanism 2 adsorbs onto the target wall. Control the first servo motor 401 and the second servo motor 402 of each of the mode conversion mechanisms to rotate, so that each of the walking wheels contacts the target wall, thereby converting the UAV from flight mode to wall climbing mode.

[0130] S5. In wall-climbing mode, the first motor 307 is controlled to drive the walking wheels to rotate and the vacuum pump 201 is controlled to adjust the magnitude of the adsorption force, so as to coordinate and control the propulsion force and the adsorption force, so that the walking wheels move on the wall surface.

[0131] In steps S4 and S5, the adsorption force of the adsorption mechanism 2 is adjusted using a closed-loop control scheme based on pressure feedback. By adjusting the negative pressure inside the adsorption chamber in real time, the change in adsorption force is precisely controlled.

[0132] Specifically, the controller collects the gas pressure information in the adsorption chamber in real time through the pressure sensor, compares it with the target pressure value determined by the optimal adsorption force adjustment curve, calculates the control error, and then obtains the output through the PID controller to drive the opening of the electronically controlled proportional valve of the vacuum pump 201. The proportional valve adjusts the pumping speed of the vacuum pump 201, and the negative pressure change is further transmitted to the adsorption chamber, forming a force control closed loop.

[0133] The parameters of the PID controller can be calibrated on the ground, enabling the closed-loop system to achieve fast, accurate, and stable pressure tracking. To further improve control performance, feedforward compensation and adaptive correction mechanisms are also introduced. The former compensates the proportional valve in advance based on the expected rate of change of adsorption force, reducing hysteresis error; the latter identifies the adsorption force model parameters in real time during flight and automatically corrects the control gain.

[0134] Closed-loop control of adsorption force can employ the classic PID control algorithm to ensure smooth adjustment of adsorption force:

[0135]

[0136] Where e is the adsorption force error (the difference between the target adsorption force and the actual adsorption force), and K p K d K i It is the gain of the PID controller. It is the rate of change of the adsorption force error.

[0137] The adsorption force closed-loop control system of the adsorption mechanism 2 improves the force tracking accuracy through robust control, which effectively ensures the high quality and repeatability of the adhesion process.

[0138] In this document, the directional terms such as front, back, top, and bottom are defined based on the position of the components in the accompanying drawings and their relative positions to each other, solely for the purpose of clarity and convenience in expressing the technical solution. It should be understood that these are relative concepts and can vary depending on different methods of use and placement; the use of these directional terms should not limit the scope of protection claimed in this application.

[0139] Where there is no conflict, the embodiments and features described above can be combined with each other. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A flying-wall-climbing dual-mode conversion unmanned aerial vehicle, characterized in that, The utility model relates to a wall surface climbing robot, including: a rack is equipped with laser radar on top; suction mechanism is arranged in the bottom of rack, and the suction mechanism includes suction cavity, vacuum pump and pressure sensor, vacuum pump connects suction cavity, and the lower end of suction cavity is equipped with soft skirt, and pressure sensor is arranged in the suction cavity and is used for detecting the air pressure in the suction cavity; a plurality of wall surface climbing mechanisms, including fixed support, walking wheel, rotor, first motor and second motor, wherein the walking wheel is rotatably mounted on the fixed support, the first motor is connected to the walking wheel to drive the walking wheel to rotate, the rotor is mounted in the walking wheel, and the second motor is connected to the rotor to drive the rotor to rotate; a plurality of modal conversion mechanisms, each of the modal conversion mechanisms is spaced around the rack, each of the modal conversion mechanisms is connected to one of the wall surface climbing mechanisms, each of the modal conversion mechanisms includes a first steering wheel and a second steering wheel, the first steering wheel is fixedly mounted on the rack and has an output end connected to the second steering wheel, the output end of the second steering wheel is connected to one of the fixed supports, and the first steering wheel and the second steering wheel are used to drive the wall surface climbing mechanism to rotate around two mutually perpendicular rotation axes; and a controller is connected to the laser radar, the vacuum pump, the pressure sensor, the first motor, the second motor, the first steering wheel and the second steering wheel respectively, wherein the controller is used to obtain target wall surface features from the laser radar, control the second motor to drive the rotor to rotate to make the unmanned aerial vehicle approach the target wall surface, control the first steering wheel and the second steering wheel to rotate to adjust the attitude of the unmanned aerial vehicle, the vacuum pump adjusts the air pressure in the suction cavity to make the suction cavity adsorb the target wall surface, and the first motor drives the walking wheel to move on the target wall surface.

2. The flight-wall climbing dual-mode conversion unmanned aerial vehicle according to claim 1, characterized in that: The suction cavity includes a fixed plate, a sealing cover and a movable plate, the fixed plate is fixed to the bottom of the rack, the sealing cover is a multi-layer folded cavity structure, the upper end of the sealing cover is connected to the fixed plate, the lower end is connected to the movable plate, and the soft skirt is connected to the upper end of the movable plate and arranged around the movable plate.

3. The flight-wall climbing dual-mode conversion unmanned aerial vehicle according to claim 1, wherein: The walking wheel includes a hub, the hub includes a hub outer ring, a hub inner ring and a plurality of connecting plates connected between the hub outer ring and the hub inner ring, the second motor is mounted in the hub inner ring, and the rotor is located in front of the hub inner ring and connected to the second motor.

4. The flight-wall climbing dual-mode conversion unmanned aerial vehicle according to claim 3, characterized in that: The front edge of the hub outer ring is also provided with a forwardly extending protective cover, the protective cover is a hollow structure, and the rotor is located in the protective cover.

5. The flight-wall climbing dual-mode conversion unmanned aerial vehicle according to claim 3, characterized in that: The rotor includes two spiral blades and a blade support, one end of the two spiral blades coincides and is fixed to the blade support, and the blade support is connected to the second motor.

6. The flight-wall climbing dual-mode conversion unmanned aerial vehicle according to claim 3, characterized in that: The first motor is connected to the walking wheel through a gear set, the gear set includes a driving gear and a driven gear, the driving gear is rotatably mounted on the fixed support, the driven gear is sleeved and mounted on the hub inner ring, the driving gear and the driven gear are engaged, and the first motor is connected to the driving gear.

7. The flight-wall climbing dual-mode conversion unmanned aerial vehicle according to claim 1, wherein: The top of the rack is provided with an upwardly extending radar support, and the laser radar is installed on the radar support.

8. The flight-wall climbing dual-mode conversion unmanned aerial vehicle according to claim 1, wherein: The rack is rectangular, and the number of the wall climbing mechanisms is four, and the four wall climbing mechanisms are respectively arranged at the four corners of the rack. 9.A method for motion control of a flight-wall climbing dual-mode conversion unmanned aerial vehicle, characterized in that: The application is applied to the flight-wall climbing dual-mode conversion unmanned aerial vehicle of any one of claims 1-8, and comprises the following steps: S1, obtaining target wall features and current state information of the unmanned aerial vehicle through the laser radar; S2, combining the target wall features and the current state information of the unmanned aerial vehicle to establish a modal conversion dynamics model; S3, taking the modal conversion dynamics model as a constraint, taking the minimization of state tracking error and control cost as an objective, constructing a cost function, and using gradient method to solve the cost function on line to obtain an optimal adsorption force adjustment curve and an optimal trajectory control command; S4, controlling the input of the second motor of each wall climbing mechanism according to the optimal trajectory control command to drive the rotor to rotate, so that the unmanned aerial vehicle approaches the target wall, and controlling the size of the adsorption force of the vacuum pump according to the optimal adsorption force adjustment curve to make the adsorption mechanism adsorb to the target wall, and controlling the first steering gear and the second steering gear of each modal conversion mechanism to rotate, so that each walking wheel contacts the target wall, thereby making the unmanned aerial vehicle convert from flight mode to wall climbing mode; S5, in the wall climbing mode, controlling the first motor to drive the walking wheel to rotate and the vacuum pump to adjust the size of the adsorption force, and coordinating the control of the propulsion force and the adsorption force, so that the walking wheel moves on the wall.

10. The motion control method of the flight-wall climbing dual-mode conversion unmanned aerial vehicle according to claim 9, wherein: The modal conversion dynamics model in the step S2 comprises a dynamics equation in flight mode and a dynamics equation in wall climbing mode; The dynamics equation in flight mode is: where M(q) is the mass matrix, is the Coriolis matrix, G(q) is the gravity term, τ is the external disturbance torque, and u is the control input. The dynamics equation in wall climbing mode is: where F adhesion is the adsorption force, the expression of which is F adhesion = k adhesion · p where k adhesion is the adsorption force coefficient, p is the gas pressure in the adsorption chamber; The cost function in the step S3 is: wherein a and β are weighting coefficients, q state (t) represents state variables of the UAV, q ref (t) represents the desired state, u(t) represents the control input; The control input of the optimal trajectory control command is determined according to the following method: A modal conversion function λ(t) is designed, and its value is smoothly transitioned between flight mode and wall climbing mode: where T transition is the duration of the mode conversion; The control input is: u(t) = λ(t) - u flight (t) + (1 - λ(t)) - u adhesion (t) wherein U flight (t) is the control input in the flight mode, U adhesion (t) is the suction force control input.

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