Structural angle design and performance analysis method and system for inclined thrust quad-rotor

Abstract

The invention relates to the technical field of aircraft performance analysis, and particularly discloses a structural angle design and performance analysis method and system for a tilt thrust quadrotor, and the method comprises the steps: firstly setting two-degree-of-freedom angle parameters of the tilt thrust quadrotor, and constructing a three-axis thrust equation under a body coordinate system; then enabling component forces of an x axis and a y axis in the three-axis thrust equation to be equal to zero, calculating a self-stabilization boundary of the four rotors to obtain a self-stabilization domain, calculating a lift coefficient and a yaw moment coefficient according to the three-axis thrust equation, discretizing angle parameters in the self-stabilization domain, calculating a lift coefficient value and a yaw moment coefficient value at each discrete point, and calculating a yaw moment coefficient value at each discrete point; and finally, the expected lift force efficiency and the expected yaw control efficiency are set, and the values of the angle parameters meeting the expected efficiency are solved respectively. According to the invention, the coupling relation and sensitivity between the flight performance and the two structure angles are explored from the two aspects of quantification and qualitative, and a guidance direction is provided for aircraft structure optimization.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft performance analysis, and particularly to a structural angle design and performance analysis method and system for an inclined thrust quadrotor. Background Art

[0002] Due to the ability to achieve vertical takeoff and landing and long-time hovering in narrow and changeable areas, rotor UAVs show strong development potential and application value, and have begun to receive more and more attention and research. Multi-rotor aircraft achieve attitude motion control by adjusting the magnitude and direction of the thrust of different ducts. However, ordinary-layout multi-rotor UAVs usually show poor yaw maneuverability and wind resistance. To address this problem, methods for optimizing the performance of the airframe based on vector thrust have gradually attracted attention, but there are many difficulties in the engineering implementation of this design. Therefore, scholars consider using structural design to achieve passive thrust inclination to avoid complex mechanical structure design and control. For example, the non-planar multi-rotor design scheme can achieve full controllability by adjusting the inclination angle, significantly improving the yaw control efficiency. Most of the inclination angles in these studies are single-degree-of-freedom rotation angles. Another scholar proposed a two-layer optimization method for large multi-rotor aircraft, which involves rotation angles of two degrees of freedom and successfully improves the maneuverability while ensuring high endurance.

[0003] Obviously, thrust inclination will bring a loss of lift efficiency while improving yaw maneuverability. Therefore, the balance between lift efficiency and maneuverability needs to be considered in the process of structural parameter design. Most of the existing studies focus on the inclination configuration of a single degree of freedom, especially for the inclination of two degrees of freedom, and a complete design system has not yet been formed. Therefore, based on this problem, how to construct a two-degree-of-freedom inclination angle model and analyze its performance is an urgent problem to be solved. Summary of the Invention

[0004] Aiming at the technical problems in the prior art, the present invention provides a structural angle design and performance analysis method and system for an inclined thrust quadrotor.

[0005] In the first aspect of the present invention, a structural angle design and performance analysis method for an inclined thrust quadrotor includes:

[0006] Setting the angle parameters of two degrees of freedom of the inclined thrust quadrotor, and constructing a three-axis thrust equation in the body coordinate system according to the angle parameters; the three-axis thrust equation includes the component force equations of the x-axis, y-axis, and z-axis in the body coordinate system;

[0007] Making the component forces of the x-axis and y-axis in the three-axis thrust equation equal to zero, calculating the self-stabilization boundary of the quadrotor, and obtaining the self-stabilization domain;

[0008] Calculate the lift coefficient according to the z-axis component force equation in the three-axis thrust equation, and calculate the yaw moment coefficient according to the x-axis and y-axis component force equations in the three-axis thrust equation;

[0009] Within the self-stabilizing domain, discretize the angle parameters according to the set grid step size, and calculate the lift coefficient value and yaw moment coefficient value at each discrete point;

[0010] Set the desired lift efficiency and desired yaw control efficiency, and respectively solve for the values of the angle parameters that satisfy the desired lift efficiency and desired yaw control efficiency;

[0011] Calculate the values of the angle parameters that simultaneously satisfy the desired lift efficiency and desired yaw control efficiency. If there is no solution, change the settings of the desired lift efficiency and desired yaw control efficiency, and re-execute the previous step until the values of the angle parameters that simultaneously satisfy the desired lift efficiency and desired yaw control efficiency are obtained.

[0012] Furthermore, set the angle parameters of the tilt-thrust quadrotor with two degrees of freedom, and construct the three-axis thrust equation in the body coordinate system according to the angle parameters, including:

[0013] Set the angle parameters of the tilt-thrust quadrotor with two degrees of freedom to be the angle of the rotor motor rotating around the arm and the angle between the arm and the horizontal plane of the frame ;

[0014] Obtain the thrust of a single motor according to the rotation angle of each motor The component forces on the x-axis, y-axis, and z-axis in the body coordinate system 、 、 .

[0015] Furthermore, make the component forces on the x-axis and y-axis in the three-axis thrust equation 、 equal to zero, calculate the self-stabilizing boundary of the quadrotor, and obtain the self-stabilizing domain, including:

[0016] Set the angle parameters to satisfy and when holds;

[0017] Let and , calculate and 's functional relationship , as the self-stabilizing boundary of the quadrotor;

[0018] Calculate the necessary and sufficient conditions for the functional relationship to have real solutions. The necessary and sufficient conditions are for The first value range;

[0019] Define the self-stabilizing domain as: and and respectively satisfy and the first value range.

[0020] Furthermore, calculate the lift coefficient according to the z-axis component equation in the three-axis thrust equation, including: The lift coefficient is: .

[0021] Furthermore, calculate the yaw moment coefficient according to the x-axis and y-axis component equations in the three-axis thrust equation, including:

[0022] Calculate the yaw moment generated by the thrust of a single motor ;

[0023] Consider the thrust increment caused by the rotational speed difference , and calculate the yaw moment coefficient according to the x-axis and y-axis component equations in the three-axis thrust equation and the yaw moment generated by the thrust of a single motor Calculate the yaw moment coefficient .

[0024] Furthermore, within the self-stabilizing domain, discretize the angle parameter according to the set grid step size, and calculate the lift coefficient value and yaw moment coefficient value at each discrete point, including:

[0025] According to the grid spacing Discretize and ;

[0026] According to the lift coefficient and the yaw moment coefficient Calculate the lift coefficient value and yaw moment coefficient value at each discrete point.

[0027] Furthermore, it also includes:

[0028] Take the lift coefficient value as the vertical axis, and use the discrete grid of the angle parameter as the horizontal axis and the plane where the vertical axis is located to create a three-dimensional surface plot of the angle parameter and the lift coefficient;

[0029] Take as the horizontal axis coordinate and the yaw moment coefficient value as the vertical axis coordinate to create a curve plot of the angle parameter and the yaw moment coefficient;

[0030] Conduct quantitative analysis on the three-dimensional surface plot and the curve plot.

[0031] Further, set the expected lift efficiency and the expected yaw control efficiency, and solve the values of the angular parameters that satisfy the expected lift efficiency and the expected yaw control efficiency respectively, including:

[0032] Design the expected lift efficiency , let the coordinate value on the number axis be , which generates an intersection line L with the three-dimensional surface diagram; L is the relationship that the structural angles under the expected lift efficiency and need to satisfy;

[0033] Design the expected yaw control efficiency , let the yaw moment coefficient , and solve the structural angles that satisfy the expected yaw control efficiency .

[0034] Further, calculate the values of the angular parameters that simultaneously satisfy the expected lift efficiency and the expected yaw control efficiency. If there is no solution, then change the settings of the expected lift efficiency and the expected yaw control efficiency, including:

[0035] If the angular value range corresponding to the intersection line L is , , then judge whether the structural angle satisfies . If so, the intersection point of the intersection line L and is the design value of the angle ; if not, then change the expected lift efficiency and the expected yaw control efficiency .

[0036] In the second aspect of the present invention, it is a structural angle design and performance analysis system for an inclined thrust quadrotor. The system includes a thrust equation construction module, a self-stabilizing domain calculation module, a lift coefficient calculation module, a yaw moment coefficient calculation module, and an expected value calculation module, wherein:

[0037] The thrust equation construction module is connected to the self-stabilizing domain calculation module, the lift coefficient calculation module, and the yaw moment coefficient calculation module. The thrust equation construction module is used to set the angular parameters of the two degrees of freedom of the inclined thrust quadrotor, and construct the three-axis thrust equation in the body coordinate system according to the angular parameters; the three-axis thrust equation includes the component force equations of the x-axis, y-axis, and z-axis in the body coordinate system;

[0038] ​The self-stabilization domain calculation module is connected to the thrust equation construction module, the lift coefficient calculation module, and the yaw moment coefficient calculation module. The self-stabilization domain calculation module is used to make the x-axis and y-axis component forces in the three-axis thrust equation equal to zero, calculate the self-stabilization boundary of the quadrotor, and obtain the self-stabilization domain;

[0039] The lift coefficient calculation module is connected to the thrust equation construction module, the self-stabilization domain calculation module, and the expected value calculation module. The lift coefficient calculation module is used to calculate the lift coefficient according to the z-axis component force equation in the three-axis thrust equation, and, within the self-stabilization domain, discretize the angle parameter according to the set grid step size, and calculate the lift coefficient value at each discrete point;

[0040] The yaw moment coefficient calculation module is connected to the thrust equation construction module, the self-stabilization domain calculation module, and the expected value calculation module. The yaw moment coefficient calculation module is used to calculate the yaw moment coefficient according to the x-axis and y-axis component force equations in the three-axis thrust equation, and, within the self-stabilization domain, discretize the angle parameter according to the set grid step size, and calculate the yaw moment coefficient value at each discrete point;

[0041] The expected value calculation module is connected to the lift coefficient calculation module and the yaw moment coefficient calculation module. The expected value calculation module is used to set the expected lift efficiency and the expected yaw control efficiency, and respectively solve the values of the angle parameter that satisfy the expected lift efficiency and the expected yaw control efficiency; and calculate the values of the angle parameter that simultaneously satisfy the expected lift efficiency and the expected yaw control efficiency. If there is no solution, then change the settings of the expected lift efficiency and the expected yaw control efficiency, and re-solve until the values of the angle parameter that simultaneously satisfy the expected lift efficiency and the expected yaw control efficiency are obtained.

[0042] A method and system for structural angle design and performance analysis of an inclined thrust quadrotor of the present invention first sets the angle parameters of the two degrees of freedom of the inclined thrust quadrotor and constructs the three-axis thrust equation in the body coordinate system. Then, it makes the component forces on the x-axis and y-axis in the three-axis thrust equation equal to zero, calculates the self-stabilization boundary of the quadrotor to obtain the self-stabilization domain. Next, it calculates the lift coefficient and yaw moment coefficient according to the three-axis thrust equation. After discretizing the angle parameters at a set grid step within the self-stabilization domain, it calculates the lift coefficient value and yaw moment coefficient value at each discrete point. Finally, it sets the desired lift efficiency and desired yaw control efficiency, and respectively solves the values of the angle parameters that satisfy the desired lift efficiency and desired yaw control efficiency. By establishing the functional relationship between the two degrees of freedom of inclination angle and the force / moment coefficient, the present invention explores the coupling relationship and sensitivity between flight performance and the two structural angles from both quantitative and qualitative levels, thereby obtaining an optimization scheme for the structural parameters of an inclined thrust quadrotor aircraft, providing a guiding direction for aircraft structural optimization, and also having a certain degree of generality. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0044] Figure 1 It is a flowchart of the steps of a method for structural angle design and performance analysis of an inclined thrust quadrotor according to an embodiment of the present invention;

[0045] Figure 2 It is a schematic diagram (one) of the structural angles in a method for structural angle design and performance analysis of an inclined thrust quadrotor according to an embodiment of the present invention;

[0046] Figure 3 It is a schematic diagram (two) of the structural angles in a method for structural angle design and performance analysis of an inclined thrust quadrotor according to an embodiment of the present invention;

[0047] Figure 4 It is a schematic diagram of the body of a quadrotor UAV in a method for structural angle design and performance analysis of an inclined thrust quadrotor according to an embodiment of the present invention;

[0048] Figure 5 It is a schematic diagram of the self-stabilization boundary in a method for structural angle design and performance analysis of an inclined thrust quadrotor according to an embodiment of the present invention;

[0049] Figure 6 It is a three-dimensional surface diagram of the lift coefficient in a method for structural angle design and performance analysis of an inclined thrust quadrotor according to an embodiment of the present invention;

[0050] Figure 7 For the three - dimensional surface projection diagram (1) in the structural angle design and performance analysis method of an inclined - thrust quadrotor according to an embodiment of the present invention;

[0051] Figure 8 For the three - dimensional surface projection diagram (2) in the structural angle design and performance analysis method of an inclined - thrust quadrotor according to an embodiment of the present invention;

[0052] Figure 9 For the yaw moment coefficient curve diagram in the structural angle design and performance analysis method of an inclined - thrust quadrotor according to an embodiment of the present invention;

[0053] Figure 10 For the lift efficiency parameter diagram in the structural angle design and performance analysis method of an inclined - thrust quadrotor according to an embodiment of the present invention;

[0054] Figure 11 For the structural composition diagram of the structural angle design and performance analysis system of an inclined - thrust quadrotor according to an embodiment of the present invention. Detailed implementation manners

[0055] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0056] A structural angle design and performance analysis method of an inclined - thrust quadrotor according to an embodiment of the present invention, as Figure 1 shown, includes the following steps:

[0057] Step S10: Set the angle parameters of the two degrees of freedom of the inclined - thrust quadrotor, and construct the three - axis thrust equations in the body coordinate system according to the angle parameters.

[0058] In this embodiment, the three - axis thrust equations in this step include the component force equations of the x - axis, y - axis, and z - axis in the body coordinate system. Specifically, step S10 includes:

[0059] Step S101: Set the angle parameters of the two degrees of freedom of the inclined - thrust quadrotor to be the angle of the rotor motor rotating around the arm and the angle between the arm and the horizontal plane of the frame. As Figure 2 and Figure 3 shown, they are respectively the schematic diagrams of the structural angle and the structural angle .

[0060] Step S102: Obtain the thrust of a single motor according to the rotation angle of each motor The component forces on the x-axis, y-axis, and z-axis in the body coordinate system 、 、 。The body coordinate system of the quadrotor UAV and the rotation angle directions of each motor are as Figure 4 shown. By force decomposition, the thrust of a single motor The magnitudes of the component forces in the body coordinate system can be obtained. Taking the No. 1 motor as an example, its corresponding component forces 、 、 are respectively:

[0061] (1)

[0062] (2)

[0063] (3).

[0064] The component forces of other motors 、 、 can be obtained corresponding to their positions in the body coordinate system, which will not be elaborated in the embodiments of the present invention, and the calculation methods of subsequent steps are common for each motor.

[0065] Step S20: Set the component forces on the x-axis and y-axis in the three-axis thrust equation to zero, calculate the self-stabilization boundary of the quadrotor, and obtain the self-stabilization domain.

[0066] When the component forces of the thrust on the x-axis and y-axis point to the inside of the fuselage, the restoring moment generated under the oncoming flow disturbance is beneficial to the self-stabilization of the fuselage. It can be seen that the self-stability of the fuselage depends on the directions of the component forces of the thrust on the x-axis and y-axis in the body coordinate system. Therefore, set the component forces 、 on the x-axis and y-axis in the three-axis thrust equation obtained in Step S10 to zero, that is and , solve the functional relationship between the structural angles and , derive the self-stabilization boundary constraint based on the condition that the fuselage generates a restoring moment under the oncoming flow disturbance, so as to calculate the self-stabilization boundary of the quadrotor and obtain the self-stabilization domain Ω.

[0067] Specifically, Step S20 includes:

[0068] Step S201: Set the angle parameters to satisfy and when holds.

[0069] Combined with the setting of the structural angle in this embodiment and , the value range of the known structural angle is and . Taking the No. 1 motor as an example, from Equation (1), it can be obtained that holds, that is, the component force of the thrust on the x-axis always points to the inside of the fuselage.

[0070] Step S202: Let , and , calculate the functional relationship and as , which is used as the self-stabilizing boundary of the quadrotor.

[0071] Considering Equation (2), let , and , then when the component force on the y-axis is 0, the functional relationship that the structural angles and need to satisfy is (4).

[0072] Step S203: Calculate the necessary and sufficient conditions for the existence of real solutions of the functional relationship . The necessary and sufficient conditions are the first value range of .

[0073] This step is to calculate the necessary and sufficient conditions for the existence of real solutions of Equation (4). The first value range of is: (5).

[0074] Step S204: Define the self-stabilizing domain as: , and and respectively satisfy , the first value range.

[0075] In summary, the self-stabilizing boundary of the quadrotor is defined as:

[0076] (6).

[0077] Taking and as the ordinate and abscissa respectively, the self-stabilizing boundary shown in Equation (4) is as shown by the red solid line in Figure 5 . The angle value range that satisfies the self-stabilizing boundary constraint of Equation (6) is called the self-stabilizing domain Ω, as shown by the blue shaded part in Figure 5

[0078]

[0078] Step S30: Calculate the lift coefficient according to the component force equation of the z-axis in the three-axis thrust equation, and calculate the yaw moment coefficient according to the component force equations of the x-axis and y-axis in the three-axis thrust equation.

[0079] If the lift generated at different structural angles under the same rotor speed is used as an index, the lift magnitudes corresponding to different and can be obtained according to Equation (3), and thus the lift efficiency of the airframe structure can be evaluated.

[0080] Specifically, in step S30, the lift coefficient is calculated according to the z-axis component equation in the three-axis thrust equation, including: the lift coefficient is: . It can be obtained from Equation (3) that the function of the lift coefficient with respect to the parameters and is: (7). It can be seen that both the parameters and will affect the lift efficiency of the aircraft.

[0081] The yaw moment of the UAV is composed of the x-axis and y-axis component forces of the thrust of each nozzle and the motor counter-torque. Given that the motor installation angle remains unchanged, the magnitude of the counter-torque of a single motor generated by the same rotational speed difference is the same. Therefore, at the same motor speed, the yaw moment coefficient is only related to the magnitude of the component force of the thrust.

[0082] Specifically, in step S30, the yaw moment coefficient is calculated according to the x-axis and y-axis component equations in the three-axis thrust equation, including:

[0083] First, calculate the yaw moment generated by the thrust of a single motor, which is (8), where is the distance between the motor and the center of mass of the aircraft.

[0084] If the thrust increment generated by the rotational speed difference is considered, then according to the x-axis and y-axis component equations in the three-axis thrust equation, and the yaw moment generated by the thrust of a single motor, calculate the yaw moment coefficient , that is, substituting Equations (2) and (3) into Equation (8) and expanding, the yaw moment coefficient generated by the thrust component force can be obtained as (9). It can be seen that the yaw moment generated by the rotational speed change is only related to the angle .

[0085] Qualitatively analyze the influence of the structural angle on the flight performance according to the lift coefficient and yaw moment coefficient calculated above.

[0086] Step S40: Discretize the angle parameters at a set grid step within the self-stabilization domain, and calculate the lift coefficient value and yaw moment coefficient value at each discrete point.

[0087] This step specifically includes:

[0088] Step S401: Design the grid spacing within the self-stabilizing domain , and discretize the angle parameters with respect to the grid spacing and . Then the self-stabilizing domain can be represented as a set composed of discrete points. In this embodiment, the value of the grid spacing is not specifically limited. Taking as an example, the lift coefficient values at each discrete point can be calculated from Equation (7), and the normalized results are as shown in Figure 6 . Figure 6 is a three-dimensional surface plot of the angle parameter and the lift coefficient, with the lift coefficient value as the vertical axis and the discrete grid of the angle parameter as the horizontal and vertical axes in the plane. Figure 7 is the projection of the three-dimensional surface plot on the vertical axis - vertical axis plane, Figure 8 is the projection of the three-dimensional surface plot on the horizontal axis - vertical axis plane. It can be seen from Figures 6 to 8 that the angle parameter and the lift coefficient show a monotonically decreasing trend. The angle parameter is the main factor affecting the lift efficiency. If the given parameter is given, then changing has an impact on the lift coefficient of no more than 13.2%. Through the surface curvature, it can be known that within the angle range of [0°, 25°], the sensitivity of the lift coefficient to the parameter is small, and the lift efficiency is above 80% at this time; when the angle is greater than 25°, the lift coefficient drops sharply as the angle increases.

[0089] Step S402: Calculate the lift coefficient value and the yaw moment coefficient value at each discrete point according to the lift coefficient and the yaw moment coefficient .

[0090] According to Equation (9), the specific numerical correspondence between the angle parameter and the yaw moment coefficient can be solved, and the normalized results are as shown in Figure 9 . Figure 9 is a curve plot of the angle parameter and the yaw moment coefficient, with as the horizontal axis coordinate and the yaw moment coefficient value as the vertical axis coordinate. It can be seen that the parameter within the self-stabilizing domain has an approximately linear relationship with the yaw efficiency.

[0091] Combined with the above content regarding Step S40, quantitative analysis is performed on the three-dimensional surface plot and the curve plot.

[0092] Step S50: Set the expected lift efficiency and the expected yaw control efficiency, and respectively solve for the values of the angular parameters that satisfy the expected lift efficiency and the expected yaw control efficiency.

[0093] Specifically, this step includes:

[0094] Step S501: Design the expected lift efficiency , let the coordinate value on the number axis be , which generates an intersection line L with the three-dimensional surface plot; L is the relationship that the structural angles and need to satisfy under the expected lift efficiency .

[0095] Step S502: Design the expected yaw control efficiency , let the yaw moment coefficient , and solve for the structural angles that satisfy the expected yaw control efficiency.

[0096] Considering the actual engineering constraints, the throttle control of the UAV is prone to saturation under large angular parameters, and even the situation of being unable to hover may occur. Therefore, preferably, in this embodiment, the expected lift efficiency is designed to be , that is, the purple plane in Figure 6 . The projection of the intersection line of this plane and the original surface on the horizontal axis - vertical axis plane is the functional relationship that and need to satisfy under this lift efficiency, as shown by the black solid line in Figure 10 .

[0097] As an example, select the expected yaw efficiency to be , then from Equation (9), can be solved.

[0098] Step S60: Calculate the values of the angular parameters that simultaneously satisfy the expected lift efficiency and the expected yaw control efficiency. If there is no solution, change the settings of the expected lift efficiency and the expected yaw control efficiency, and re - execute Step S50 until the values of the angular parameters that simultaneously satisfy the expected lift efficiency and the expected yaw control efficiency are obtained.

[0099] Specifically: If the angular value range corresponding to the intersection line L is , , then determine whether the structural angle satisfies . If so, the intersection point of the intersection line L and is the design value of the angle ; if not, change the expected lift efficiency and the expected yaw control efficiency .

[0100] Combined with the example in step S50, the corresponding angle range is: , , within the range of parameter values. According to Figure 10 the intersection point of the black solid line in , the value of can be determined as . If there is no solution in the solution process, the settings of the expected lift efficiency and the expected yaw control efficiency are changed, and step S50 is executed again to solve again until the values of the angle parameters that simultaneously satisfy the expected lift efficiency and the expected yaw control efficiency are obtained.

[0101] A structural angle design and performance analysis system for an inclined-thrust quadrotor according to another embodiment of the present invention, as Figure 11 shown, the system includes a thrust equation construction module 101, a self-stabilizing domain calculation module 102, a lift coefficient calculation module 103, a yaw moment coefficient calculation module 104, and an expected value calculation module 105, wherein:

[0102] The thrust equation construction module 101 is connected to the self-stabilizing domain calculation module 102, the lift coefficient calculation module 103, and the yaw moment coefficient calculation module 104. The thrust equation construction module 101 is used to set the angle parameters of the two degrees of freedom of the inclined-thrust quadrotor and construct a three-axis thrust equation in the body coordinate system; the three-axis thrust equation includes the component force equations of the x-axis, y-axis, and z-axis in the body coordinate system;

[0103] The self-stabilizing domain calculation module 102 is connected to the thrust equation construction module 101, the lift coefficient calculation module 103, and the yaw moment coefficient calculation module 104. The self-stabilizing domain calculation module 102 is used to make the component forces of the x-axis and y-axis in the three-axis thrust equation equal to zero, calculate the self-stabilizing boundary of the quadrotor, and obtain the self-stabilizing domain;

[0104] The lift coefficient calculation module 103 is connected to the thrust equation construction module 101, the self-stabilizing domain calculation module 102, and the expected value calculation module 105. The lift coefficient calculation module 103 is used to calculate the lift coefficient according to the component force equation of the z-axis in the three-axis thrust equation, and, within the self-stabilizing domain, discretize the angle parameters according to the set grid step size and calculate the lift coefficient values at each discrete point;

[0105] The yaw moment coefficient calculation module 104 is connected to the thrust equation construction module 101, the self-stabilizing region calculation module 102, and the expected value calculation module 105. The yaw moment coefficient calculation module 104 is used to calculate the yaw moment coefficient according to the component force equations of the x-axis and y-axis in the three-axis thrust equation, and, within the self-stabilizing region, discretize the angular parameters according to the set grid step size, and calculate the yaw moment coefficient values at each discrete point;

[0106] The expected value calculation module 105 is connected to the lift coefficient calculation module 103 and the yaw moment coefficient calculation module 104. The expected value calculation module 105 is used to set the expected lift efficiency and the expected yaw control efficiency, and respectively solve the values of the angular parameters that satisfy the expected lift efficiency and the expected yaw control efficiency; and calculate the values of the angular parameters that simultaneously satisfy the expected lift efficiency and the expected yaw control efficiency. If there is no solution, then change the settings of the expected lift efficiency and the expected yaw control efficiency, and re-solve until the values of the angular parameters that simultaneously satisfy the expected lift efficiency and the expected yaw control efficiency are obtained.

[0107] The implementation method of the above structural angle design and performance analysis system for the tilt-thrust quadrotor can refer to the relevant steps of the foregoing method embodiments, and will not be elaborated here.

[0108] A structural angle design and performance analysis method and system for a tilt-thrust quadrotor of the present invention first sets the angular parameters of the two degrees of freedom of the tilt-thrust quadrotor and constructs a three-axis thrust equation in the body coordinate system, then makes the component forces of the x-axis and y-axis in the three-axis thrust equation equal to zero, calculates the self-stabilizing boundary of the quadrotor to obtain the self-stabilizing region, and then calculates the lift coefficient and the yaw moment coefficient according to the three-axis thrust equation. After discretizing the angular parameters according to the set grid step size within the self-stabilizing region, calculate the lift coefficient values and the yaw moment coefficient values at each discrete point. Finally, set the expected lift efficiency and the expected yaw control efficiency, and respectively solve the values of the angular parameters that satisfy the expected lift efficiency and the expected yaw control efficiency. The present invention explores the coupling relationship and sensitivity between flight performance and two structural angles from both quantitative and qualitative levels by establishing the functional relationship between the two-degree-of-freedom inclination angle and the force / moment coefficient, thereby obtaining an optimization scheme for the structural parameters of the tilt-thrust quadrotor aircraft, providing a guiding direction for aircraft structure optimization, and also having a certain degree of generality.

[0109] The above further describes the present invention with the aid of specific embodiments. However, it should be understood that the specific description here should not be construed as a limitation on the essence and scope of the present invention. Various modifications made by those of ordinary skill in the art to the above embodiments after reading this specification all fall within the scope protected by the present invention.

Claims

1. A structural angle design and performance analysis method for a tilt-thrust quadrotor, characterized in that: include: Setting angle parameters of the two degrees of freedom of the tilt-thrust quadrotor, and constructing a three-axis thrust equation in the body coordinate system according to the angle parameters; the three-axis thrust equation includes component force equations of the x-axis, y-axis and z-axis in the body coordinate system; The components of the x-axis and y-axis in the three-axis thrust equation are set to zero, and the self-stabilizing boundary of the quadrotor is calculated to obtain the self-stabilizing domain; Calculating the lift coefficient according to the component force equation of the z-axis in the three-axis thrust equation, and calculating the yaw moment coefficient according to the component force equations of the x-axis and y-axis in the three-axis thrust equation; In the self-stabilizing domain, the angle parameter is discretized according to a set grid step size, and the lift coefficient value and the yaw moment coefficient value at each discrete point are calculated; The desired lift efficiency and the desired yaw control efficiency are set, and the values ​​of the angle parameters that satisfy the desired lift efficiency and the desired yaw control efficiency are respectively solved; Calculate the value of the angle parameter that satisfies both the expected lift efficiency and the expected yaw control efficiency. If there is no solution, change the settings of the expected lift efficiency and the expected yaw control efficiency, and re-execute the previous step until the value of the angle parameter that satisfies both the expected lift efficiency and the expected yaw control efficiency is obtained.

2. The structural angle design and performance analysis method of a tilt-thrust quadrotor according to claim 1, characterized in that: The angle parameters of the two degrees of freedom of the tilt-thrust quadrotor are set, and the three-axis thrust equations in the body coordinate system are constructed according to the angle parameters, including: The angle parameters of the two degrees of freedom of the tilt-thrust quadrotor are set to be the angles at which the rotor motor rotates around the arm. Angle between the arm and the horizontal plane of the frame ; Get the thrust of a single motor according to the rotation angle of each motor The x-axis, y-axis and z-axis components in the body coordinate system , , .

3. The structural angle design and performance analysis method of a tilt-thrust quadrotor according to claim 2, characterized in that: Let the x-axis and y-axis components of the three-axis thrust equation be , Equal to zero, calculate the self-stabilization boundary of the quadrotor, and obtain the self-stabilization domain, including: Set the angle parameters to meet as well as hour, Established; make ,and ,calculate and Functional relationship , as the self-stabilizing boundary of the quadrotor; Calculate the functional relationship The necessary and sufficient conditions for the existence of real solutions are as follows: The first value interval of ; Define the self-stabilizing domain as: ,and and Satisfy , the first value interval.

4. The structural angle design and performance analysis method of a tilt-thrust quadrotor according to claim 3, characterized in that: Calculating the lift coefficient according to the component force equation of the z-axis in the three-axis thrust equation includes: the lift coefficient is: .

5. The structural angle design and performance analysis method of a tilt-thrust quadrotor according to claim 4, characterized in that: The yaw moment coefficient is calculated based on the x-axis and y-axis component force equations in the three-axis thrust equation, including: Calculate the yaw moment generated by a single motor thrust ; Considering the speed difference to generate thrust increment , and according to the component force equations of the x-axis and y-axis in the three-axis thrust equation and the yaw moment generated by the thrust of a single motor Calculating the Yaw Moment Coefficient .

6. The structural angle design and performance analysis method of a tilt-thrust quadrotor according to claim 5, characterized in that: In the self-stabilizing domain, the angle parameter is discretized according to a set grid step size, and the lift coefficient value and the yaw moment coefficient value at each discrete point are calculated, including: According to the grid spacing right and Discretize According to the lift coefficient And the yaw moment coefficient Calculate the lift coefficient and yaw moment coefficient at each discrete point.

7. The structural angle design and performance analysis method of a tilt-thrust quadrotor according to claim 6, characterized in that: Also includes: With the lift coefficient value as the vertical axis and the discrete grid of the angle parameter as the plane where the horizontal and vertical axes are located, a three-dimensional surface diagram of the angle parameter and the lift coefficient is made; by As the horizontal axis coordinate, the yaw moment coefficient value is used as the vertical axis coordinate, and a curve graph of the angle parameter and the yaw moment coefficient is drawn; The three-dimensional surface graph and the curve graph are quantitatively analyzed.

8. The structural angle design and performance analysis method of a tilt-thrust quadrotor according to claim 7, characterized in that: Set the expected lift efficiency and the expected yaw control efficiency, and solve the values ​​of the angle parameters that meet the expected lift efficiency and the expected yaw control efficiency, including: Design expected lift efficiency , let the axis coordinate value be , which intersects the three-dimensional surface diagram to form an intersection line L; L is the desired lift efficiency Lower structure angle and Relationships that need to be satisfied; Design expected yaw control efficiency , let the yaw moment coefficient , solve the structural angle that meets the desired yaw control efficiency .

9. The structural angle design and performance analysis method of a tilt-thrust quadrotor according to claim 8, characterized in that: Calculate the value of the angle parameter that satisfies both the desired lift efficiency and the desired yaw control efficiency. If there is no solution, change the settings of the desired lift efficiency and the desired yaw control efficiency, including: If the angle corresponding to the intersection line L is in the range of , , then determine the structural angle Is it satisfied? , if so, then the intersection line L and The intersection point is the angle Design value ; If not, change the expected lift efficiency and expected yaw control efficiency .

10. A structural angle design and performance analysis system for a tilt-thrust quadrotor, characterized in that: The system includes a thrust equation building module, a self-stabilizing domain calculation module, a lift coefficient calculation module, a yaw moment coefficient calculation module and an expected value calculation module, wherein: The thrust equation construction module is connected to the self-stabilization domain calculation module, the lift coefficient calculation module, and the yaw moment coefficient calculation module. The thrust equation construction module is used to set the angle parameters of the two degrees of freedom of the tilt-thrust quadrotor, and construct the three-axis thrust equation in the body coordinate system according to the angle parameters; the three-axis thrust equation includes the component force equations of the x-axis, y-axis and z-axis in the body coordinate system; The self-stabilization domain calculation module is connected to the thrust equation construction module, the lift coefficient calculation module, and the yaw moment coefficient calculation module. The self-stabilization domain calculation module is used to make the x-axis and y-axis components in the three-axis thrust equation equal to zero, calculate the self-stabilization boundary of the quadrotor, and obtain the self-stabilization domain; The lift coefficient calculation module is connected to the thrust equation construction module, the self-stabilization domain calculation module, and the expected value calculation module. The lift coefficient calculation module is used to calculate the lift coefficient according to the z-axis component equation in the three-axis thrust equation, and, in the self-stabilization domain, discretize the angle parameter according to a set grid step size, and calculate the lift coefficient value at each discrete point; The yaw moment coefficient calculation module is connected to the thrust equation construction module, the self-stabilization domain calculation module, and the expected value calculation module. The yaw moment coefficient calculation module is used to calculate the yaw moment coefficient according to the component force equations of the x-axis and the y-axis in the three-axis thrust equation, and, in the self-stabilization domain, discretize the angle parameter according to the set grid step size, and calculate the yaw moment coefficient value at each discrete point; The expected value calculation module is connected to the lift coefficient calculation module and the yaw moment coefficient calculation module. The expected value calculation module is used to set the expected lift efficiency and the expected yaw control efficiency, and respectively solve the values ​​of the angle parameters that meet the expected lift efficiency and the expected yaw control efficiency; and calculate the values ​​of the angle parameters that simultaneously meet the expected lift efficiency and the expected yaw control efficiency. If there is no solution, the settings of the expected lift efficiency and the expected yaw control efficiency are changed, and the solution is re-solved until the values ​​of the angle parameters that simultaneously meet the expected lift efficiency and the expected yaw control efficiency are obtained.

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