Hydrofoil device, hydrofoil sliding control method and cross-medium unmanned aerial vehicle

Abstract

The invention belongs to the field of cross-medium unmanned aerial vehicles, and particularly relates to a hydrofoil device, a hydrofoil sliding control method and a cross-medium unmanned aerial vehicle, and a hydrofoil comprises a vertical plate, a bottom plate, a hydrofoil, an underwater propeller and a depth gauge; the other end of the vertical plate is fixedly connected with the bottom plate; hydrofoils are rotationally arranged on the two sides of the bottom plate, underwater propellers are fixedly arranged on the hydrofoils, the propelling direction of the underwater propellers faces the downstream of the hydrofoils, and the underwater propeller further comprises a hydrofoil angle adjusting mechanism used for driving the hydrofoils to deflect. The hydrofoil has the water-air medium-crossing capacity, and by means of the high-efficiency control capacity of the hydrofoil propelled by the depth meter and the differential vector, the hydrofoil can keep a certain underwater immersion depth, and the unmanned aerial vehicle connected with the hydrofoil can slide at a high speed across the medium on the water surface.

Description

Technical Field

[0001] The present invention belongs to the field of cross-media UAVs, and specifically relates to a hydrofoil device, a hydrofoil gliding control method and a cross-media UAV. Background Art

[0002] As a means of transportation, the hydrofoil device can generate lifting force when moving in water, thereby lifting the connected objects out of the water and greatly reducing the fluid resistance. The original unpowered hydrofoil device relied on the change of human gravitational potential energy to move forward, and on this basis, a propeller can be directly added to achieve unpowered forward movement. However, this structural design can only simply realize the hydrofoil device gliding on the water surface, but cannot realize underwater diving and cross-medium transformation between water and air.

[0003] That is, the existing electric hydrofoil device is mainly used for hydrofoil surfboards to glide on the water surface. Such electric hydrofoil propellers are generally directly installed on the hydrofoil, with a fixed thrust direction, and cannot be flexibly moved underwater and cannot be integrated with drones. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a hydrofoil device, a hydrofoil gliding control method and a cross-media UAV which can keep the hydrofoil submerged at a certain depth in water and enable a UAV connected to the hydrofoil device to form a cross-media UAV for high-speed gliding on the water surface.

[0005] The present invention provides a hydrofoil device, comprising a vertical plate, a bottom plate, a hydrofoil, an underwater propeller and a depth gauge; One end of the vertical plate is used to connect to the cross-medium drone, and the other end is fixedly connected to the bottom plate; Hydrofoils are rotatably arranged on both sides of the bottom plate, and underwater thrusters are fixedly arranged on the hydrofoils. The propulsion direction of the underwater thrusters is toward the downstream of the hydrofoils, and a hydrofoil angle adjustment mechanism for driving the hydrofoils to deflect is also included. Furthermore, the depth meter includes a water level meter and a pressure sensor, and the water level meter and the pressure sensor are coupled to collect depth data.

[0006] Furthermore, a water level gauge is arranged on the front side of the vertical plate.

[0007] Furthermore, a pressure sensor is arranged downstream of the connection between the bottom plate and the vertical plate.

[0008] Furthermore, the hydrofoil angle adjustment mechanism is a steering gear fixedly arranged on the bottom plate, and the hydrofoil is fixedly arranged on the output shaft of the steering gear.

[0009] Furthermore, a steering gear installation hole is provided on the bottom plate, and the steering gear is embedded in the steering gear installation hole; The upper and lower surfaces of the bottom plate are detachably fixed with servo pressure plates, which are used to fix the servo and provide a streamlined outer surface.

[0010] Furthermore, the thickness of the hydrofoil at one end close to the bottom plate gradually becomes thinner than that at one end far from the bottom plate.

[0011] Furthermore, a cable trough is provided in the downstream direction of the vertical plate, and the lines of the underwater propeller and the hydrofoil angle adjustment mechanism are led to one end of the vertical plate for connecting to the cross-medium UAV through the cable trough; Wire baffles are arranged at intervals on the outside of the wire trough.

[0012] The present invention also provides a hydrofoil glide control method, the hydrofoil glide control method controls a cross-medium UAV and the above-mentioned hydrofoil device, the upper end of the vertical plate of the hydrofoil device is fixedly arranged on the fuselage of the cross-medium UAV, the hydrofoil glide control method is applied to a hydrofoil glide control device, the hydrofoil glide control device comprises an immersion depth controller, a roll attitude controller, a pitch attitude controller and a control distribution model unit, the input end of the immersion depth controller is used to access the immersion depth measured by the depth gauge on the above-mentioned hydrofoil, the input ends of the roll attitude controller and the pitch attitude controller are respectively used to connect to the remote controller of the cross-medium UAV, the output ends of the immersion depth controller and the roll attitude controller are connected to the input end of the control distribution model unit, the input end of the control distribution model unit is also used to access the throttle amount given by the remote controller, the output end of the pitch attitude controller is used to connect to the horizontal tail through the flight controller of the cross-medium UAV, the output end of the control distribution model unit is used to connect the hydrofoil angle adjustment mechanism and the underwater thruster of the above-mentioned hydrofoil device, the immersion depth controller uses a proportional-integral controller plus a feedforward control scheme, and the pitch attitude controller and the roll attitude controller both use a proportional-integral-differential controller plus a feedforward control scheme; The hydrofoil gliding control method comprises the steps of: Obtaining a submerged depth set value given to a submerged depth controller, a pitch attitude set value of a pitch attitude controller, and a roll attitude set value of a roll attitude controller; the pitch attitude set value and the roll attitude set value are both specified by a remote controller; The forward thrust obtained by mapping the throttle amount of the remote controller of the cross-medium UAV is used to perform forward thrust control and the three-axis attitude control of the hydrofoil is performed using the flight controller; generating an immersion depth controller output through an immersion depth controller according to the immersion depth setting value and the immersion depth measured by the depth gauge; generating a pitch attitude controller output and a roll attitude controller output through a pitch attitude controller and a roll attitude controller according to a pitch attitude given value and a roll attitude given value respectively; The throttle amount given by the remote controller, the output of the immersion depth controller and the output of the roll attitude controller are input into the control distribution model unit; Using the control allocation result generated by the control allocation model unit, the submerged depth control and the rolling attitude control are performed through the hydrofoil angle adjustment mechanism and the underwater propeller of the hydrofoil device of the cross-medium UAV; The output of the pitch attitude controller is passed to the horizontal tail through the flight controller to perform pitch attitude control.

[0013] The present invention also provides a cross-media UAV, comprising the above-mentioned hydrofoil device of the UAV.

[0014] The beneficial effect of the present invention is that the hydrofoil device of the present invention forms a hydrofoil with differential vector propulsion through two hydrofoils with independently controllable angles and two underwater thrusters with independently controllable thrusts, which can realize flexible movement of the hydrofoil on the water surface and underwater, and complete yaw, pitch and roll actions. At the same time, it has the ability to cross the medium between water and air, and with the help of the depth meter combined with the efficient control ability of the hydrofoil with differential vector propulsion, the hydrofoil can maintain a certain immersion depth in the water, so that the UAV connected to the hydrofoil device can form a high-speed glide on the water surface across the medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 is a schematic structural diagram of a hydrofoil device in one embodiment; Attached Figure 2 is a front view of a hydrofoil device in one embodiment; Attached Figure 3 For attachment Figure 2 Middle AA section view; Attached Figure 4 A partial explosion schematic diagram of a hydrofoil device in one embodiment; Attached Figure 5 is a block diagram of a module structure of a hydrofoil gliding control device in one embodiment; Attached Figure 6 1 is a flow chart of a hydrofoil gliding control method according to an embodiment; Attached Figure 7 A schematic diagram of an intermediate equivalent effectiveness analysis in one embodiment; Attached Figure 8 is a side view of a hydrofoil device in one embodiment; Attached Fig. 9 This is a flow chart of using Newton's method to solve an optimization problem in one embodiment.

[0016] In the figure, 1-hydrofoil gliding control device; 11-immersion depth controller; 13-roll attitude controller; 15-pitch attitude controller; 17-control distribution model unit; 2-vertical plate; 21-wire trough; 22-wire baffle; 3-bottom plate; 31-servo mounting hole; 32-servo pressure plate; 4-hydrofoil; 5-underwater thruster; 6-hydrofoil angle adjustment mechanism; 7-water level gauge; 8-pressure sensor. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0019] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0020] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0022] As attached Figure 1 -Attached Figure 4 As shown, the present invention provides a hydrofoil device, comprising a vertical plate 2, a bottom plate 3, a hydrofoil 4, an underwater propeller 5 and a depth gauge, wherein the depth gauge is used to provide hydrofoil depth data support for hydrofoil gliding control; One end of the vertical plate 2 is used to connect the cross-medium UAV. Specifically, the vertical plate 2 and the cross-medium UAV can be detachably connected by fasteners, or can be integrally formed with the fuselage of the cross-medium UAV. The other end is fixedly connected to the bottom plate 3. Similarly, the vertical plate 2 and the bottom plate 3 can be detachably connected by fasteners, or can be integrally formed with the bottom plate 3. Preferably, the vertical plate 2 is arranged in the middle of the bottom plate 3, so that the vertical plate 2 and the bottom plate 3 are in a T-shaped structure. Hydrofoils 4 are rotatably arranged on both sides of the base plate 3, and underwater thrusters 5 are fixedly arranged on the hydrofoils 4. The propulsion direction of the underwater thrusters 5 is toward the downstream of the hydrofoil 4. It also includes a hydrofoil angle adjustment mechanism 6 for driving the hydrofoil 4 to deflect. The two hydrofoil angle adjustment mechanisms 6 can control the angle of the hydrofoil 4 oppositely, and the two underwater thrusters 5 can independently control the thrust. Specifically, the hydrofoil 4 can be rotatably connected to the side of the base plate 3 through a rotating connection structure, and the hydrofoil angle adjustment mechanism 6 is used to drive the hydrofoil 4 to rotate. The hydrofoil angle adjustment mechanism 6 can also be fixedly arranged on the base plate 3, and the hydrofoil 4 is directly fixed on the output shaft of the hydrofoil angle adjustment mechanism 6, or the hydrofoil angle adjustment mechanism 6 is fixedly arranged on the hydrofoil 4, and the output shaft of the hydrofoil angle adjustment mechanism 6 is fixed on the base plate 3. The specific connection method is selected according to actual needs.

[0023] The hydrofoil device of the present invention forms a hydrofoil with differential vector propulsion through two hydrofoils 4 with independently controllable angles and two underwater thrusters 5 with independently controllable thrusts, which can realize flexible movement of the hydrofoil on the water surface and underwater, and complete yaw, pitch and roll actions. At the same time, it has the ability to cross the medium between water and air, and with the help of the depth meter combined with the efficient control ability of the hydrofoil with differential vector propulsion, the hydrofoil can maintain a certain immersion depth in the water, so that the UAV connected to the hydrofoil can form a high-speed glide on the water surface across the medium. In one embodiment, the depth meter includes a water level meter 7 and a pressure sensor 8. The water level meter 7 and the pressure sensor 8 are coupled to collect depth data. The specific coupling method is the existing technology and will not be described in detail here.

[0024] In one embodiment, the water level meter 7 is arranged on the front side of the vertical plate 2. Preferably, the water level meter 7 is arranged in a strip shape in front of the vertical plate 2 to ensure the accuracy of water level data collection. At the same time, it can be integrated with the vertical plate 2 without increasing the underwater movement resistance of the hydrofoil.

[0025] In one of the embodiments, the pressure sensor 8 is disposed downstream of the connection between the bottom plate 3 and the vertical plate 2. Similarly, the pressure sensor 8 is disposed at a position that avoids increasing the underwater movement resistance of the hydrofoil while ensuring accurate acquisition of pressure data.

[0026] In one preferred embodiment, the hydrofoil angle adjustment mechanism 6 is a steering gear fixedly mounted on the bottom plate 3, and the hydrofoil 4 is fixedly mounted on the output shaft of the steering gear. In this way, the rotational coordination and angle control of the hydrofoil 4 and the bottom plate 3 can be achieved, and the connection strength of the hydrofoil 4 can be ensured.

[0027] In one embodiment, a steering gear mounting hole 31 is provided on the bottom plate 3, and the steering gear is embedded in the steering gear mounting hole 31. Such a configuration can simplify the installation and positioning of the steering gear on the one hand, and avoid excessive increase in the thickness of the bottom plate 3 on the other hand; The bottom plate 3 has servo pressure plates 32 detachably fixed on its upper and lower surfaces. The servo pressure plates 32 are used to fix the servo and provide a streamlined outer surface, that is, the servo pressure plates 32 limit and lock the servo on the servo mounting hole 31, thereby improving the fixing stability of the servo. In addition, the servo pressure plates 32 can provide physical protection for the servo and increase its service life. In addition, the outer wall of the servo pressure plates 32 is streamlined to avoid the protrusion at the connection between the servo and the pressure plate increasing the resistance of the hydrofoil device to move forward in the water.

[0028] In one of the embodiments, the thickness of the hydrofoil 4 at one end close to the bottom plate 3 gradually becomes thinner than that at the end far from the bottom plate 3, so that the resistance of the hydrofoil 4 moving forward in the water can be reduced while ensuring the structural strength and guiding effect of the hydrofoil 4.

[0029] In one embodiment, a wire groove 21 is provided in the downstream direction of the vertical plate 2, and the lines of the underwater propeller 5 and the hydrofoil angle adjustment mechanism 6 are led to the vertical plate 2 through the wire groove 21 for connecting one end of the cross-medium UAV, thereby facilitating the connection of the wires, that is, facilitating the docking of the lines, and avoiding the resistance of the lines in the water. In addition, the wire groove 21 can reduce the weight of the vertical plate 2; Wire baffles 22 are arranged at intervals outside the wire trough 21. The wire baffles 22 can prevent the wires from escaping from the wire trough 21, thereby improving the installation stability of the wires.

[0030] The present invention also provides a hydrofoil gliding control method, which controls a cross-medium UAV and the above-mentioned hydrofoil device. The upper end of the vertical plate 2 of the hydrofoil device is fixedly arranged on the fuselage of the cross-medium UAV, and a hydrofoil gliding control device 1 is provided for use, thereby controlling the above-mentioned hydrofoil device, such as Figure 5As shown, the hydrofoil gliding control device 1 includes an immersion depth controller 11, a roll attitude controller 13, a pitch attitude controller 15 and a control distribution model unit 17. The input end of the immersion depth controller 11 is used to access the immersion depth measured by the depth gauge on the hydrofoil device. The input ends of the roll attitude controller 13 and the pitch attitude controller 15 are respectively used to connect the remote controller of the cross-medium UAV. The output ends of the immersion depth controller 11 and the roll attitude controller 13 are connected to the input end of the control distribution model unit 17, and the input end of the control distribution model unit 17 is also used to access the throttle amount given by the remote controller. The output end of the pitch attitude controller 15 is used to connect the horizontal tail through the flight controller of the cross-medium UAV. The output end of the control distribution model unit 17 is used to connect the hydrofoil angle adjustment mechanism 6 and the underwater thruster 5 of the hydrofoil device. The immersion depth controller 11 uses a proportional-integral controller plus a feedforward control scheme. The pitch attitude controller 15 and the roll attitude controller 13 both use a proportional-integral-differential controller plus a feedforward control scheme.

[0031] like Figure 6 As shown, the hydrofoil gliding control method may include the following processing steps S10 to S22: S10, obtaining a submergence depth set value given to the submergence depth controller, a pitch attitude set value of the pitch attitude controller, and a roll attitude set value of the roll attitude controller; the pitch attitude set value and the roll attitude set value are both specified by the remote controller; S12, performing forward thrust control using the forward thrust obtained by mapping the throttle amount of the remote controller of the cross-medium UAV and performing three-axis attitude control of the hydrofoil using the flight controller; S14, generating an immersion depth controller output through an immersion depth controller according to the immersion depth setting value and the immersion depth measured by the depth gauge; S16, generating a pitch attitude controller output and a roll attitude controller output through a pitch attitude controller and a roll attitude controller according to the pitch attitude given value and the roll attitude given value respectively; S18, inputting the throttle amount given by the remote controller, the immersion depth controller output and the roll attitude controller output into the control distribution model unit; S20, using the control allocation result generated by the control allocation model unit to perform immersion depth control and rolling attitude control through the hydrofoil angle adjustment mechanism 6 and the underwater propeller 5 of the hydrofoil device of the cross-medium UAV; S22, using the pitch attitude controller output to send it to the horizontal tail through the flight controller to perform pitch attitude control.

[0032] It can be understood that the controlled parameters of the hydrofoil's gliding control in this embodiment include forward thrust, three-axis attitude (x, y, z) and the immersion depth of the hydrofoil in the water. Among them, the three-axis attitude can be controlled by the built-in controller of the existing flight controller PX4, and the forward thrust can be obtained by mapping the throttle amount of the remote controller of the cross-medium drone, so it is necessary to design the immersion depth controller 11 to output the desired force in the vertical direction. Since the controller calculates the desired force and the desired torque of a certain axis, it is necessary to design a control distribution model to make the hydrofoil actually generate these desired forces and desired torques. Among them, the vertical direction desired force, horizontal direction desired force, rolling desired torque and yaw desired torque of the hydrofoil are the model inputs of the control distribution model, and the desired angle of attack of the hydrofoils 4 on both sides of the hydrofoil device and the desired thrust of the underwater thrusters 5 on both sides of the hydrofoil are the model outputs of the control distribution model. This control distribution model is nonlinear.

[0033] It can be understood that, first of all, the design of the immersion depth controller 11: the controlled parameter is the immersion depth of the hydrofoil in the water, which is measured by the depth gauge on the hydrofoil device. The output of the immersion depth controller 11 is the desired force in the vertical direction. The control scheme is a control scheme using a proportional-integral controller (PI) plus a feedforward (FF), in which the feedforward part is used to compensate for gravity, and the compensation amount is obtained by measuring the fuselage weight of the cross-medium drone; the proportional part is used to stabilize the immersion depth controller 11 and realize the adjustment in the vertical direction; the integral part is used to compensate for the error of the feedforward part, thereby eliminating the steady-state error in the control and realizing zero-difference adjustment. The parameters of the immersion depth controller 11 are obtained by the empirical parameter adjustment method.

[0034] The overall control block diagram of hydrofoil gliding control is as follows: Figure 5 As shown in the figure, PID is a proportional-integral-differential controller, P is a proportional controller, and RC_setpoint is an important concept in drone control. It is usually used to set the position, speed, acceleration, resultant force, yaw angle, and yaw angular velocity of the drone. These control instructions can be issued by using the mavros / setpoint_raw / local command of the existing mavros library. Mixer is a mixer, PI is a proportional-integral control unit, FF is a feedforward control unit, and the output f zbd The square device is the square root operation module, the circle node is the summation node, and IMU is the inertial measurement unit. Figure 5 middle, h d represents a given value of depth, Represents a measurement of depth, represents the given value of the roll angle, Represents the measured value of the roll angle, q d represents the given value of the roll angular rate, The conversion formula between the Euler coordinate system and the body coordinate system is: represents the measured value of the roll angular rate, l d represents the output value of the roll controller, f xbd Indicates the throttle value given by the remote controller. f zbd represents the output value of the immersion depth controller 11, T 1c represents the expected thrust of the left underwater propeller 5, T 2c represents the expected thrust of the right underwater propeller 5, represents the desired angle of the left hydrofoil 4, represents the desired angle of the right hydrofoil 4, represents the given value of the pitch angle, represents the measured value of the pitch angle, p d represents the given value of the pitch rate, represents the measured value of the pitch angular rate, m d represents the output value of the pitch controller, Indicates the desired horizontal tail angle.

[0035] The pitch attitude, roll attitude and immersion depth of the hydrofoil are controlled by independent controllers. Among them, the controller of the immersion depth part is as mentioned above, and the pitch attitude and roll attitude both use the PID+feedforward control scheme. For gliding, the immersion depth of the hydrofoil can be kept at a constant value, so the given value of the controller of the immersion depth part is a fixed value, and the given values ​​of the pitch attitude controller 15 and the roll attitude controller 13 are both specified by the remote control of the cross-medium UAV. The output of the pitch attitude controller 15 is handed over to the horizontal tail for execution through the controller (such as Mixer) provided by the flight controller PX4; while the output of the controller of the immersion depth part and the roll attitude controller 13 are input together with the throttle amount given by the remote control into the nonlinear control allocation model unit 17 introduced below, and the obtained control allocation result is handed over to the hydrofoil angle adjustment mechanism 6 and the underwater thruster 5 on both sides for execution.

[0036] The above-mentioned hydrofoil gliding control method obtains the immersion depth of the hydrofoil through a depth gauge installed on the hydrofoil device (depth data is collected by coupling a pressure sensor and a water level gauge), and uses a designed control method to keep the hydrofoil at a given immersion depth, so that other components installed on the hydrofoil can be accurately placed above the water surface to reduce resistance. The underwater propeller 5 of the hydrofoil device is kept below the water surface and the blades of the underwater propeller 5 are completely immersed, which can provide maximum thrust during gliding and realize the rapid gliding of the cross-medium UAV on the water surface.

[0037] In one embodiment, the control allocation model unit 17 maps the immersion depth controller output and the roll attitude controller output to the actuator inputs of the hydrofoil angle adjustment mechanism 6 and the underwater thruster 5 of the hydrofoil device of the cross-medium UAV based on intermediate equivalent force analysis and solved by Newton's method.

[0038] It can be understood that for a nonlinear control allocation model: the process of control allocation is the process of calculating the actuator input based on the controller output.

[0039] (1) First, define the coordinate system as follows: b System: It is the fuselage coordinate system, the conventional front ( x )-right( y )-Down( z ) coordinate system.

[0040] s System: Assume that the sideslip angle of the aircraft is 0, x The axis points in the direction of the incoming flow. y Axis and b During the taxiing process, the height of the aircraft is kept in a small range, so it can be approximately considered that the s system x When the axis is kept horizontal and the roll angle of the aircraft is 0, the s system z The axis is pointed vertically downward.

[0041] (2) Define the controller output parameters, including the horizontal forward desired force , vertical upward expectation , Rolling desired moment and the desired yaw moment .

[0042] (3) The intermediate equivalent effect is as follows: In order to map the controller output to the actuator input, it is necessary to analyze the force of the hydrofoil device in the water. b The analysis is carried out under the assumption that the force exerted by water on the underwater assembly is only: First, the impact of water on the hydrofoil z Directional force; Second, the water on the underwater propeller 5 x Direction and z Direction of force.

[0043] The above two forces are considered to act on a point fixed to the fuselage, and the points of action of the two forces on each side coincide, so the two forces on each side can be combined. Considering the hydrofoil 4 and underwater propeller 5 on each side as a whole, there are four forces exerted by water on the underwater assembly, namely, x Directional force andz Directional force.

[0044] Intermediate equivalence analysis Figure 7 As shown, is the water acting on the right side point x Directional force, in b The following indicates. The water acts on the left point x Directional force, in b The following indicates. is the water acting on the right side point z Directional force, in b The following indicates. The water acts on the left point z Directional force, in b These four forces are called intermediate equivalent forces. is the desired rolling moment, b The following indicates. is the desired yaw moment, b The following is indicated. is the distance between the action points on both sides. Then the process of control allocation becomes to calculate the intermediate equivalent force according to the controller output, and then calculate the actuator input according to the intermediate equivalent force.

[0045]

[0046]

[0047]

[0048]

[0049]

[0050] First, according to the pitch angle of the aircraft, s The desired thrust under the system is mapped to b system, and then the intermediate equivalent forces can be calculated based on simple mechanical relations.

[0051] (4) Calculate the actuator input based on the intermediate equivalent force: The side view of the hydrofoil device is as follows Figure 8 As shown, taking the left hydrofoil 4 and the underwater propeller 5 as an example, according to the principles of fluid mechanics, it is simplified to assume that the lift is proportional to the square of the speed and the angle of attack, and the following relationship can be listed:

[0052]

[0053] in, The additional angle of attack brought by the pitch of the aircraft, that is, the pitch angle of the aircraft; is the forward velocity in the s system, equivalent to the gliding speed; is the coefficient obtained by simulation for calculating lift; is the thrust of the underwater propeller 5, is the angle of the hydrofoil 4 relative to the fuselage, is the forward speed of the fuselage. The right hydrofoil 4 and underwater propeller 5 are similar to those on the left, and can be described by the above relationship. Solving the equation in the previous section can get the actuator input, but this equation does not have an analytical solution, so it is converted into the following optimization problem:

[0054] In one embodiment, the process of solving the problem using Newton's method includes: Initialization, select the initial value of the solution; Calculate the residual vector; Check whether the convergence condition is met; the convergence condition includes that the modulus length of the residual vector is less than a preset threshold or the number of iterations reaches the maximum number of iterations; If satisfied, the iterative solution is terminated and the actuator input is obtained; If it is not satisfied, the Jacobian matrix and the update vector are calculated, the variables are updated and then projected to the feasible domain, and the step of calculating the residual vector is returned; the feasible domain is a closed interval.

[0055] (5) Use Newton's method to solve the optimization problem in the previous section, such as Fig. 9 The solution process is shown below: First, initialize and select the initial value to solve:

[0056] Then calculate the residual vector, the residual vector is a 2×1 vector whose elements are and Values:

[0057] Then the convergence condition is checked. If the modulus of the residual vector is less than a preset threshold or the maximum number of iterations is reached, the convergence condition is met, otherwise it is not met.

[0058] Compute the Jacobian matrix, whose elements are and ,right and The partial derivative of is expressed as follows:

[0059] Solve the linear equations to get the update vector:

[0060] Update variables, update and Values:

[0061]

[0062] Project the variable to the feasible domain. The feasible domain here is a closed interval. Therefore, when the variable is greater than the upper bound, set it equal to the upper bound; when the variable is less than the lower bound, set it equal to the lower bound. k and k +1 indicates the two adjacent iterations.

[0063] It should be understood that although Figure 6 The steps in the method are shown in sequence as indicated by the arrows, but the steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of the steps, and the steps can be executed in other orders. Figure 6 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequentially, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0064] In one embodiment, Figure 5 As shown, a hydrofoil gliding control device 1 is provided, comprising an immersion depth controller 11, a roll attitude controller 13, a pitch attitude controller 15 and a control allocation model unit 17. The input end of the immersion depth controller 11 is used to access the immersion depth measured by the depth gauge on the hydrofoil device, and the input ends of the roll attitude controller 13 and the pitch attitude controller 15 are respectively used to connect the remote controller of the cross-medium UAV. The output ends of the immersion depth controller 11 and the roll attitude controller 13 are connected to the input end of the control allocation model unit 17, and the input end of the control allocation model unit 17 is also used to access the throttle amount given by the remote controller. The output end of the pitch attitude controller 15 is used to connect the horizontal tail through the flight controller of the cross-medium UAV. The output end of the control allocation model unit 17 is used to connect the hydrofoil angle adjustment mechanism 6 and the underwater thruster 5 of the hydrofoil device, and the immersion depth controller 11 uses a proportional-integral controller plus a feedforward control scheme. The pitch attitude controller 15 and the roll attitude controller 13 both use a proportional-integral-differential controller plus a feedforward control scheme.

[0065] The forward thrust obtained by mapping the throttle amount of the remote controller of the cross-medium UAV is used to perform forward thrust control and the three-axis attitude control of the hydrofoil is performed by the flight controller. The immersion depth controller output is generated by the immersion depth controller 11 according to the given immersion depth constant and the immersion depth measured by the depth meter. The pitch attitude controller output and the roll attitude controller output are generated by the pitch attitude controller 15 and the roll attitude controller 13 according to the pitch attitude given value and the roll attitude given value specified by the remote controller respectively. The throttle amount, the immersion depth controller output and the roll attitude controller output given by the remote controller are input into the control allocation model unit 17. The control allocation result generated by the control allocation model unit 17 is used to perform immersion depth control and roll attitude control through the hydrofoil angle adjustment mechanism 6 and the underwater thruster 5 of the hydrofoil device of the cross-medium UAV. The pitch attitude controller output is used to be handed over to the horizontal tail through the flight controller to perform pitch attitude control.

[0066] The above-mentioned hydrofoil gliding control device 1 obtains the immersion depth of the hydrofoil through a depth gauge installed on the hydrofoil device (depth data is collected by coupling a pressure sensor and a water level gauge), and uses a designed control method to keep the hydrofoil at a given immersion depth, so that other components installed on the hydrofoil can be accurately placed above the water surface to reduce resistance. The underwater propeller 5 propeller of the hydrofoil device is kept below the water surface and the blades of the underwater propeller 5 are completely immersed, which can provide maximum thrust during gliding and realize the rapid gliding of the cross-medium UAV on the water surface.

[0067] In one embodiment, the control allocation model unit 17 maps the immersion depth controller output and the roll attitude controller output to the actuator inputs of the hydrofoil angle adjustment mechanism 6 and the underwater thruster 5 of the hydrofoil device of the cross-medium UAV based on intermediate equivalent force analysis and solved by Newton's method.

[0068] In one embodiment, the process of solving the problem using Newton's method includes: Initialization, select the initial value of the solution; Calculate the residual vector; Check whether the convergence condition is met; the convergence condition includes that the modulus length of the residual vector is less than a preset threshold or the number of iterations reaches the maximum number of iterations; If satisfied, the iterative solution is terminated and the actuator input is obtained; If it is not satisfied, the Jacobian matrix and the update vector are calculated, the variables are updated and then projected to the feasible domain, and the step of calculating the residual vector is returned; the feasible domain is a closed interval.

[0069] It can be understood that for the specific limitations of the hydrofoil gliding control device 1, reference can be made to the corresponding limitations of the hydrofoil gliding control method described above, which will not be repeated here.

[0070] The present invention also provides a cross-media UAV, comprising a UAV and the above-mentioned hydrofoil device.

[0071] The above is only an embodiment and does not limit the present invention in any way. Any person skilled in the art can use the above disclosed technical contents to make many possible changes, modifications or modifications to the technical solutions of the present invention into equivalent embodiments of equivalent changes without departing from the scope of the technical solutions of the present invention. Therefore, any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A hydrofoil device, characterized in that: It comprises a vertical plate (2), a bottom plate (3), a hydrofoil (4), an underwater propeller (5) and a depth gauge; One end of the vertical plate (2) is used for connecting to the cross-medium drone, and the other end is fixedly connected to the bottom plate (3); The hydrofoils (4) are rotatably arranged on both sides of the bottom plate (3), the underwater propellers (5) are fixedly arranged on the hydrofoils (4), the propulsion direction of the underwater propellers (5) is toward the downstream of the hydrofoils (4), and a hydrofoil angle adjustment mechanism (6) for driving the hydrofoils (4) to deflect is also included.

2. The hydrofoil device according to claim 1, characterized in that: The depth meter comprises a water level meter (7) and a pressure sensor (8), and the water level meter (7) and the pressure sensor (8) are coupled to collect depth data.

3. The hydrofoil device according to claim 2, characterized in that: The water level gauge (7) is arranged on the front side of the vertical plate (2).

4. The hydrofoil device according to claim 2, characterized in that: The pressure sensor (8) is arranged downstream of the connection between the bottom plate (3) and the vertical plate (2).

5. The hydrofoil device according to claim 1, characterized in that: The hydrofoil angle adjustment mechanism (6) is a steering gear fixedly arranged on the bottom plate (3), and the hydrofoil (4) is fixedly arranged on the output shaft of the steering gear.

6. The hydrofoil device according to claim 5, characterized in that: The bottom plate (3) is provided with a steering gear mounting hole (31), and the steering gear is embedded in the steering gear mounting hole (31); The bottom plate (3) is detachably fixed with a steering gear pressure plate (32) on its upper and lower surfaces, and the steering gear pressure plate (32) is used to fix the steering gear and provide a streamlined outer surface.

7. The hydrofoil device according to claim 1, characterized in that: The thickness of the hydrofoil (4) at an end close to the bottom plate (3) gradually becomes thinner than that at an end far from the bottom plate (3).

8. The hydrofoil device according to claim 1, characterized in that: A cable trough (21) is provided in the downstream direction of the vertical plate (2), and the lines of the underwater propeller (5) and the hydrofoil angle adjustment mechanism (6) are led to the vertical plate (2) through the cable trough (21) for connecting to one end of the cross-medium UAV; Wire baffles (22) are arranged at intervals outside the wire trough (21).

9. A hydrofoil gliding control method, characterized in that: The hydrofoil gliding control method controls a cross-media UAV and a hydrofoil device as described in any one of claims 1 to 8, wherein the upper end of the vertical plate (2) of the hydrofoil device is fixedly arranged on the fuselage of the cross-media UAV, and the hydrofoil gliding control method is applied to a hydrofoil gliding control device (1), wherein the hydrofoil gliding control device (1) comprises an immersion depth controller, a roll attitude controller, a pitch attitude controller and a control allocation model unit, wherein the input end of the immersion depth controller is used to access the immersion depth measured by the depth meter on the hydrofoil device as described in any one of claims 1 to 8, and the input ends of the roll attitude controller and the pitch attitude controller are respectively used to connect to the remote controller of the cross-media UAV. , the output ends of the immersion depth controller and the roll attitude controller are connected to the input end of the control allocation model unit, the input end of the control allocation model unit is also used to access the throttle amount given by the remote controller, the output end of the pitch attitude controller is used to connect the horizontal tail through the flight controller of the cross-medium UAV, the output end of the control allocation model unit is used to connect the hydrofoil angle adjustment mechanism (6) and the underwater thruster (5) of the hydrofoil device according to any one of claims 1 to 8, the immersion depth controller uses a proportional-integral controller plus a feedforward control scheme, and the pitch attitude controller and the roll attitude controller both use a proportional-integral-differential controller plus a feedforward control scheme; The hydrofoil gliding control method comprises the steps of: Acquire a submergence depth set value given to the submergence depth controller, a pitch attitude set value of the pitch attitude controller, and a roll attitude set value of the roll attitude controller; the pitch attitude set value and the roll attitude set value are both specified by a remote controller; The forward thrust obtained by mapping the throttle amount of the remote controller of the cross-medium UAV is used to perform forward thrust control and the three-axis attitude control of the hydrofoil is performed using the flight controller; generating an immersion depth controller output through the immersion depth controller according to the immersion depth setting value and the immersion depth measured by the depth gauge; generating a pitch attitude controller output and a roll attitude controller output through the pitch attitude controller and the roll attitude controller according to the pitch attitude given value and the roll attitude given value respectively; Inputting the throttle amount given by the remote controller, the immersion depth controller output and the roll attitude controller output into the control allocation model unit; Using the control allocation result generated by the control allocation model unit, the hydrofoil angle adjustment mechanism (6) and the underwater propeller (5) of the hydrofoil device of any one of claims 1 to 7 of the cross-medium UAV are used to perform immersion depth control and rolling attitude control; The pitch attitude controller output is delivered to the horizontal tail through the flight controller to perform pitch attitude control.

10. A cross-media drone, characterized in that: The invention comprises a drone and a hydrofoil device as described in any one of claims 1 to 8.

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