Control method of unmanned aerial vehicle with multi-degree-of-freedom flight mode

Abstract

The control method for a drone with multiple degrees of freedom flight modes according to the present invention includes: a fuselage section equipped with a battery, the forward direction of which is set as the x-axis; multiple rotors, four or more arranged around the fuselage section, each rotor having its rotation axis aligned in the z-axis direction; an x-axis tilting mechanism section for tilting the multiple rotors about axes parallel to the x-axis; a y-axis tilting mechanism section for tilting the multiple rotors about axes parallel to the y-axis; a first drive motor section for driving the y-axis tilting mechanism section; a second drive motor section for driving the x-axis tilting mechanism section; and a control section for controlling the first rotor, the second rotor, the third rotor, the fourth rotor, the first drive motor section, and the second drive motor section to realize multiple flight modes.

Description

Technical Field

[0001] This invention relates to a control method for an unmanned aerial vehicle (UAV) with multiple degrees of freedom flight modes. Background Technology

[0002] Multi-rotor or multi-fan aircraft, often referred to as drones, are typically a type of helicopter with three or more rotors. Compared to traditional single-rotor helicopters, their advantages include the ability to change rotor torque and speed, and ease of maintenance and operation. Due to these advantages and the rapid development of electronic technology, the application areas of multi-rotor aircraft have expanded rapidly. While previously dominated by larger military drones, more recently smaller civilian drones have been produced. Their applications have also expanded from image capture to various fields such as cargo transportation.

[0003] Among various types of small unmanned aerial vehicles (UAVs), quadcopters, in particular, have several advantages over other types. The biggest advantage is their extremely simple mechanical mechanism. Quadcopters do not require pre-flight trimming, exhibit minimal mechanical vibration, and have a low probability of component failure due to aging. Furthermore, due to their simple shape, quadcopters are mathematically easy to model, making them suitable for autonomous flight. Unlike other small UAVs that require extensive training to adjust, even beginners can easily operate them. Additionally, the use of multiple small propellers makes them relatively safe for those unfamiliar with operation or management. In other words, even without specialized knowledge of aircraft or extensive prior training, quadcopters can be easily operated, maintained, and managed. Thanks to these advantages, the influence of quadcopters in the civilian small UAV market is gradually expanding.

[0004] Numerous researchers have studied the control and guidance of quadrotors. Firstly, in the control domain, to effectively handle the characteristics of the quadrotor's nonlinear model, backstepping or sliding mode techniques are used to directly control the nonlinear system. There are also attempts to use feedback linearization to linearize the quadrotor model before control. Secondly, in the guidance domain, not only can flip maneuvers that rotate the quadrotor fuselage 360 ​​degrees or more in one direction be performed, but also rapid maneuvers based on specific trajectories and attitudes, and sophisticated maneuvers such as ball swapping, can be achieved.

[0005] Thanks to the contributions of numerous researchers, while multi-rotor aircraft, including quadcopters, can now be precisely controlled and guided, their functionality still requires improvement. Because the precise position and attitude of an aircraft in three-dimensional space are represented by six variables, multi-rotor systems ultimately become underactuated systems, where the input dimension is smaller than the output dimension. This limitation restricts the control and guidance of multi-rotor aircraft. For example, to accelerate a multi-rotor forward, its main body must tilt forward; when a multi-rotor is tilted backward, no forward acceleration will be generated. In other words, the attitude and acceleration of a multi-rotor aircraft cannot be completely independent.

[0006] Therefore, when a camera is attached to the body of a multirotor aircraft to photograph a target, if the multirotor changes direction, its body will also tilt, causing the camera's shooting direction to deviate from the target. Furthermore, since changing direction requires the entire multirotor to tilt, the responsiveness is relatively low, making rapid maneuvers difficult. For these reasons, using a separate device to hold the camera in place according to changes in the aircraft's angle increases components, cost, and weight, and shortens battery life. Additionally, because this camera attachment device is susceptible to vibration, a separate dust extraction device is required, resulting in increased complexity.

[0007] *Relevant Existing Technologies

[0008] Korean Patent Publication No. 10-2017-0061941 (Published on June 7, 2017)

[0009] Korean Patent No. 10-1692315 (granted on December 28, 2016) Summary of the Invention

[0010] Technical problems to be solved

[0011] The purpose of this invention is to enable drones to stably have multiple degrees of freedom and achieve multiple flight modes without the need for additional devices to install cameras, and to maintain a stable state without shaking.

[0012] Another objective of this invention is to minimize air resistance experienced by the drone by reducing the difference between the azimuth angle of the fuselage and the forward speed of the drone.

[0013] Another object of the present invention is to provide a maneuver that fixes the azimuth angle of the fuselage to a specific target point by adjusting the tilt angle of the rotor.

[0014] Another objective of this invention is to provide a control method for a drone that allows the angle of the fuselage to be freely manipulated regardless of the drone's direction of travel, enabling the operator to perform a variety of tasks.

[0015] Problem-solving methods

[0016] According to the control method of the unmanned aerial vehicle (UAV) with multi-degree-of-freedom flight modes of the present invention, the UAV includes: a fuselage section equipped with a battery, the forward direction of which is set as the x-axis; a first rotor and a second rotor, each with its rotation axis arranged in the z-axis direction, and positioned opposite each other with the fuselage section as the center when viewed from the x-axis direction; a third rotor and a fourth rotor, each with its rotation axis arranged in the z-axis direction, and positioned opposite each other with the fuselage section in the y-axis direction when viewed from the x-axis direction; and a first frame shaft, rotatably supported by the fuselage section at the first position with an axis y1 parallel to the y-axis as the center, and located at both ends. The first rotor and the second rotor are supported by support shafts parallel to the x-axis; the second frame shaft, at the second position, is rotatably supported by the fuselage about a y2 axis parallel to the y-axis, and at both ends supports the third rotor and the fourth rotor based on support shafts parallel to the x-axis; the third frame shaft, relative to the first frame shaft, is spaced apart in the z-axis direction based on a plurality of first rods, and moves based on a force parallel to the y-axis, causing the first rotor and the second rotor to tilt about axes parallel to the x-axis; the fourth frame shaft, relative to the second... A frame axis, spaced apart along the z-axis by multiple second rods, moves based on a force parallel to the y-axis, causing the third and fourth rotors to tilt about axes parallel to the x-axis; a first drive motor, connected via a first conversion mechanism, provides a force parallel to the y-axis to the third and fourth frame axes; a second drive motor, connected via a second conversion mechanism, provides a force to the first and second frame axes, causing them to rotate about axes y1 and y2 respectively; and a control unit controls the first rotor, the second rotor, and the third... The control method, which includes a tri-rotor, a fourth rotor, a first drive motor, and a second drive motor to achieve multiple flight modes, comprises the following steps: in order to make the UAV fly according to the input values, setting the speed from the first rotor to the fourth rotor and the tilt angle from the first rotor to the fourth rotor; calculating the difference between the azimuth angle of the fuselage and the forward speed of the UAV in the trajectory; and if the difference between the azimuth angle of the fuselage and the forward speed of the UAV exceeds a reference value, changing the tilt angle from the first rotor to the fourth rotor to reduce the difference between the azimuth angle and the forward speed of the UAV.

[0017] According to one embodiment of the present invention, the control method further includes the following steps: receiving a target pointing point; during the movement of the UAV according to the trajectory, in order to change the azimuth angle of the fuselage so that the fuselage continues to face the target pointing point, changing the tilt angle of the first rotor to the fourth rotor.

[0018] According to one embodiment of the present invention, the control method further includes the following steps: inputting an arbitrary angle mode regarding the azimuth angle of the fuselage; inputting the tilt angle from the first rotor to the fourth rotor; and changing the azimuth angle of the fuselage by changing the tilt angle from the first rotor to the fourth rotor according to the input tilt angle.

[0019] According to one embodiment of the present invention, the plurality of flight modes may include: a first flight mode in which both the first drive motor and the second drive motor are stopped, and the speeds of the first rotor to the fourth rotor are controlled individually; and a second flight mode in which the first drive motor and the second drive motor are started individually, and the speeds of the first rotor to the fourth rotor are controlled individually.

[0020] According to one embodiment of the present invention, the first flight mode may include: a first-1 flight mode in which the fuselage tilts toward the x-axis or moves toward the y-axis; a first-2 flight mode in which the fuselage tilts toward the y-axis or moves toward the x-axis; a first-3 flight mode in which the fuselage rotates about the z-axis; and a first-4 flight mode in which the fuselage moves toward the z-axis.

[0021] According to one embodiment of the present invention, the second flight mode may include: a 2-1 flight mode in which the fuselage is kept horizontal, the first rotor to the fourth rotor are tilted about axes parallel to the x-axis, and the fuselage is moved in the y-axis direction; a 2-2 flight mode in which the fuselage is kept horizontal, the first rotor to the fourth rotor are tilted about axes parallel to the y-axis, and the fuselage is moved in the y-axis direction; and a 2-3 flight mode in which the fuselage is kept horizontal, and the first rotor to the fourth rotor are individually controlled. The speed of the rotor causes the fuselage to rotate around the z-axis; Flight modes 2-4 keep the fuselage horizontal and individually control the speed of the first to fourth rotors to move the fuselage in the z-axis direction; Flight modes 2-5 cause the first to fourth rotors to rotate around axes parallel to the x-axis, causing the fuselage to rotate relative to the x-axis; and Flight modes 2-6 cause the first to fourth rotors to rotate around axes parallel to the y-axis, causing the fuselage to rotate relative to the y-axis.

[0022] According to one embodiment of the present invention, the second to fifth flight modes may include: making the rotation axes of the first to the fourth rotors parallel to the z-axis, rotating the fuselage relative to the x-axis, and maintaining an attitude in which the fuselage is tilted relative to the ground.

[0023] According to one embodiment of the present invention, the second to sixth flight modes may include: making the rotation axes of the first to the fourth rotors parallel to the z-axis, rotating the fuselage relative to the y-axis, and maintaining an attitude in which the fuselage is tilted relative to the ground.

[0024] This invention also includes a control method for a drone with multiple degrees of freedom flight modes. The drone includes: a fuselage section equipped with a battery, the forward direction of which is set to the x-axis; multiple rotors, four or more arranged around the fuselage section, each rotor's rotation axis neatly arranged in the z-axis direction; an x-axis tilting mechanism section for tilting the multiple rotors about axes parallel to the x-axis; a y-axis tilting mechanism section for tilting the multiple rotors about axes parallel to the y-axis; a first drive motor section for driving the y-axis tilting mechanism section; a second drive motor section for driving the x-axis tilting mechanism section; and a control unit for controlling the first rotor, the first rotor, the second rotor, the third rotor, the fourth rotor, the fifth rotor, the sixth rotor, the seventh rotor, the y-axis tilting mechanism section, the y-axis tilting mechanism section, the y-axis tilting mechanism section, the y-axis tilting mechanism section, the y-axis tilting mechanism section, the y-axis tilting mechanism section, the y-axis tilting mechanism section, and the y-axis tilting mechanism section. The control method, which includes two rotors, a third rotor, a fourth rotor, a first drive motor, and a second drive motor to achieve multiple flight modes, comprises the following steps: in order to make the UAV fly according to the input values, setting the speed of the first rotor to the fourth rotor and the tilt angle of the first rotor to the fourth rotor; calculating the difference between the azimuth angle of the fuselage and the forward speed of the UAV in the trajectory; and if the difference between the azimuth angle of the fuselage and the forward speed of the UAV exceeds a reference value, changing the tilt angle of the first rotor to the fourth rotor to reduce the difference between the azimuth angle and the forward speed of the UAV.

[0025] The effects of the invention

[0026] The UAV with multiple degrees of freedom flight modes according to the present invention enables multiple rotors to tilt independently with the x-axis and y-axis as the center. Even when the rotors are hovering, changing their attitude or speed, the main body can maintain its original attitude or be set to a specific attitude, thereby enabling multiple flight modes.

[0027] According to one example of the present invention, by individually controlling the speed of multiple rotors, a first flight mode with 4 degrees of freedom can be achieved, and a second flight mode with 6 degrees of freedom can be achieved by tilting multiple rotors in the x-axis and y-axis directions.

[0028] According to one embodiment of the present invention, based on the input, with the speed and tilt angle of the first to fourth rotors set, the difference between the azimuth angle of the fuselage and the forward speed of the drone is obtained in the trajectory of the drone. When the difference exceeds a reference value, the tilt angle of the first to fourth rotors is changed to reduce the difference between the azimuth angle of the fuselage and the forward speed of the drone, thereby minimizing the air resistance experienced by the drone.

[0029] According to one example of the present invention, in order to change the azimuth angle of the fuselage and keep the fuselage pointing toward the target point during the movement of the UAV along the trajectory, the tilt angle of the first rotor to the fourth rotor is changed, so that multiple tasks can be performed in one or a group flight.

[0030] According to another example of the invention, while the drone is moving along a specific trajectory, the angle of the fuselage can be freely manipulated regardless of the drone's direction of travel, allowing the operator to perform a variety of tasks. Attached Figure Description

[0031] Figure 1 This is a perspective view of an example of a drone 100 according to the present invention.

[0032] Figure 2 It is shown Figure 1 A 3D view of the drone 100 with its casing 111 disassembled.

[0033] Figure 3 Viewed from below Figure 2 A 3D view of the drone 100.

[0034] Figure 4 It is shown Figure 2 A 3D image showing multiple rotors tilted around the y-axis in a specific configuration.

[0035] Figure 5 It is shown Figure 2 A 3D image showing multiple rotors tilted around the x-axis in a specific configuration.

[0036] Figure 6 yes Figure 2 A 3D image showing multiple rotors tilted around the x-axis and y-axis in a state of equilibrium.

[0037] Figures 7 to 13 The posture of the drone 200 of the present invention based on a first flight mode is shown.

[0038] Figure 7 This indicates a state of equilibrium.

[0039] Figure 8 and Figure 9 This shows the forward and backward movement (x-axis direction) and rotation about the y-axis of the drone.

[0040] Figure 10 and Figure 11 This shows the drone's left and right movement (y-axis direction) and rotation about the x-axis.

[0041] Figure 12 This illustrates the concept of a drone moving in the z-axis direction.

[0042] Figure 13 The image shows the drone rotating around the z-axis.

[0043] Figures 14 to 17 The diagram illustrates a posture of the UAV 200 based on a second flight mode that differs from the first flight mode.

[0044] Figure 14 The drone is shown moving forward and backward.

[0045] Figure 15 The drone is shown moving left and right.

[0046] Figure 16 The fuselage is shown rotating about the x-axis.

[0047] Figure 17 The fuselage is shown rotating around the y-axis.

[0048] Figures 18 to 22 This is a diagram used to describe the various flight modes and control methods of the present invention. Detailed Implementation

[0049] The UAV with multi-degree-of-freedom flight modes of the present invention will now be described in detail with reference to the accompanying drawings. In this specification, even in different embodiments, the same or similar components are referred to by the same or similar reference numerals, and their description can be found in the preceding description.

[0050] according to Figure 1 The UAV 100 with multi-degree-of-freedom flight mode of the present invention has a central fuselage 110 and a plurality of rotors 121, 122, 123, and 124 disposed around the fuselage 110. In order to support the plurality of rotors 121, 122, 123, and 124, a first frame shaft 131, a second frame shaft 132, a third frame shaft 133, and a fourth frame shaft 134 are disposed on the fuselage 110.

[0051] For ease of explanation, if a coordinate system is defined, the fuselage 110 is positioned along the front-to-back direction (x-axis), the left-to-right direction (y-axis), and the up-to-down direction (z-axis). The rotation axes of the multiple rotors 121, 122, 123, and 124 are arranged along the z-axis.

[0052] Multiple rotors can be installed in pairs at multiple locations along the 110x axis of the fuselage. Figure 1 This is one such example, showing that two pairs are arranged. Specifically, at the rear end of the fuselage section 110, the first rotor 121 and the second rotor 122 form a pair, and at the front end of the fuselage section 110, the third rotor 123 and the fourth rotor 124 form a pair. The first rotor 121 and the second rotor 122 are supported by the first frame shaft 131 and the third frame shaft 133, while the third rotor 123 and the fourth rotor 124 are supported by the second frame shaft 132 and the fourth frame shaft 134.

[0053] Multiple rotors 121, 122, 123, and 124 are supported by support shafts 136, 137, 138, and 139 parallel to the x-axis. Support shafts 136, 137, 138, and 139 serve two purposes: firstly, to provide space for cables supplying power to the multiple rotors; and secondly, to act as primary support points for controlling the tilting of the rotors 121, 122, 123, and 124.

[0054] The body 110 can be a configuration where a casing 111 covers multiple internal components. A camera 112 can be mounted on the front of the body 110. For example... Figure 2 The camera 112 is directly mounted on a substrate or similar material, and no additional stabilizer or other components are used to reduce swaying. This is due to the fact that the components and flight modes of the drone of the present invention, described later, reduce the swaying of the camera 112 and accurately and easily orient the camera 112 in the desired direction.

[0055] like Figure 2 The fuselage 110 is equipped with a battery 113 to supply power to multiple components. In order to reduce the power consumption of the battery 113 and increase flight time, the present invention omits the aforementioned stabilizer and additional components, thereby reducing the corresponding weight.

[0056] The multiple frame shafts 131, 132, 133, and 134 used to support the multiple rotors 121, 122, 123, and 124 adopt a structure that can be both 'fixed' and 'tilted'. For example, the multiple frame shafts include: a first frame shaft 131, located at the rear end of the fuselage section 110, supported by the fuselage section 110, and capable of rotating about a y1 axis parallel to the y-axis; a second frame shaft 132, located at the front end of the fuselage section 110, supported by the fuselage section 110, and capable of rotating about a y2 axis parallel to the y-axis; a third frame shaft 133, positioned relative to the first frame shaft 131 and spaced apart in the z-axis direction by multiple first rods 141 and 142; and a fourth frame shaft 134, positioned relative to the second frame shaft 132 and spaced apart in the z-axis direction by multiple second rods 143 and 144. That is, the first frame shaft 131 and the second frame shaft 132 are supported by the fuselage 110 and can rotate in the y-axis direction. Although the third frame shaft 133 and the fourth frame shaft 134 are not fixed relative to the fuselage 110, they are, based on the various rods 141, 142, 143, and 144, moved relative to the first frame shaft 131 and the second frame shaft 132 under a constrained state due to driving force. In this example, the third frame shaft 133 and the fourth frame shaft 134 move in the y-axis direction, causing the support shafts 136, 137, 138, and 139 that primarily support the multiple rotors 121, 122, 123, and 124 to rotate around their respective axes parallel to the x-axis.

[0057] A first conversion mechanism is provided to drive the third frame shaft 133 and the fourth frame shaft 134. This first conversion mechanism receives the driving force from the first drive motor 150 and converts it into a force that moves the third frame shaft 133 and the fourth frame shaft 134 in a direction parallel to the y-axis. However, because the third frame shaft 133 and the fourth frame shaft 134 are constrained by the first rods 141 and 142, they move relative to the first frame shaft 131 and the second frame shaft 132 in directions that rotate around axes x1 and x2, respectively, which are parallel to the x-axis. The first conversion mechanism is provided with a first transmission rod 151 to simultaneously transmit the driving force of the first drive motor 150 to the third frame shaft 133 and the fourth frame shaft 134. The first transmission rod 151 extends in the x-axis direction and rotates due to the rotational force transmitted by the first drive motor 150. At its opposite end, the connecting rod member rotates, causing the third frame shaft 133 and the fourth frame shaft 134 to move simultaneously in the y-axis direction.

[0058] like Figure 3The first frame shaft 131 and the second frame shaft 132 are connected by a second conversion mechanism, which is connected by a second drive motor 160. The second conversion mechanism transmits the rotational force of the second drive motor 160, causing the first frame shaft 131 and the second frame shaft 132 to rotate around their respective rotation axes y1 and y2. The second conversion mechanism has a second transmission rod 161 capable of simultaneously transmitting the driving force of the second drive motor 160 to both the first frame shaft 131 and the second frame shaft 132. The second transmission rod 161 also extends in the x-axis direction, receiving the driving force of the second drive motor 160 and moving in the x-axis direction, thereby providing the torque necessary to rotate the first frame shaft 131 and the second frame shaft 132.

[0059] Reference Figures 4 to 6 Describe the function of this structure. Figure 4 The diagram illustrates how the second transmission rod 161 moves in the x-axis direction due to the driving force of the second drive motor 160, causing the first frame shaft 131 and the second frame shaft 132 to rotate. As a result, the first rotor 121 and the second rotor 122 rotate around the y1 axis, and the third rotor 123 and the fourth rotor 124 rotate around the y2 axis. This tilting of the multiple rotors 121, 122, 123, and 124 in the y-axis direction results in a change in their angle relative to the fuselage 110, and the thrust of the multiple rotors 121, 122, 123, and 124 is tilted in the y-axis direction relative to the fuselage 110.

[0060] Figure 5 The diagram illustrates how the first transmission rod 151 rotates around the x-axis due to the driving force of the first drive motor 150, causing the third frame shaft 133 and the fourth frame shaft 134 to move in the y-axis direction. As a result, the support shafts 136, 137, 138, and 139 supporting the multiple rotors 121, 122, 123, and 124 rotate in the x1 and x2 axes respectively, and the multiple rotors 121, 122, 123, and 124 also rotate in the same direction. This tilting of the multiple rotors 121, 122, 123, and 124 will guide them to tilt (tilt left or right) relative to the fuselage 110 around the x-axis or move (move left or right) in the y-axis direction.

[0061] Figure 6 The diagram shows that both the first drive motor 150 and the second drive motor 160 are in operation, resulting in the multiple rotors 121, 122, 123, and 124 tilting towards the x-axis and y-axis, respectively. This tilting of the multiple rotors 121, 122, 123, and 124 ultimately causes the fuselage section 110 to move or tilt in a diagonal direction.

[0062] The multi-degree-of-freedom unmanned aerial vehicle 100 of the present invention includes a control unit that enables multiple flight modes by controlling multiple rotors 121, 122, 123, 124 and a first drive motor unit 150 and a second drive motor unit 160. The control unit precisely adjusts the tilt of the multiple rotors 121, 122, 123, 124 by controlling the speed of the multiple rotors 121, 122, 123, 124 or the movement or rotation angle of the first drive motor unit 150 and the second drive motor unit 160. A wireless communication module is provided on the fuselage 110 for communication with a ground-based remote controller, and the control unit implements the flight mode based on input signals.

[0063] The following reference Figure 7 The flight modes of the multi-degree-of-freedom unmanned aerial vehicle 200 of the present invention are described. In these figures, the plurality of rotors 221, 222, 223, 224 correspond to the aforementioned plurality of rotors 121, 122, 123, 124, and the components supporting or tilting these plurality of rotors 221, 222, 223, 224 are also the same as those described above. However, simplified representations are used for ease of understanding.

[0064] The multiple flight modes of the multi-degree-of-freedom UAV 200 of the present invention may include 4-degree-of-freedom modes and 6-degree-of-freedom modes. These 4-degree-of-freedom modes and 6-degree-of-freedom modes can be implemented independently, or simultaneously, depending on the situation.

[0065] Figures 7 to 13 The posture of the first flight mode of the drone 200 based on the present invention is shown.

[0066] Figure 7 The diagram illustrates the rotational states of multiple rotors 221, 222, 223, and 224 used to achieve a balanced state. Specifically, for the fuselage 210 of the drone to hover stably, the rotation directions of the multiple rotors 221, 222, 223, and 224, which are diagonally opposite, must be consistent, and the rotors arranged side-by-side must rotate in opposite directions. If the rotational speeds of the multiple rotors 221, 222, 223, and 224 are the same, the fuselage 210 can remain horizontal. Since the magnitude of the propulsive force from the rotor rotation is consistent with the magnitude of the drone 200's gravity, the drone 200 can stably achieve hovering maneuvers. In this example, the multiple rotors 221, 222, 223, and 224 of the drone 200 do not require additional tilting and are controlled by motor speed.

[0067] Figure 8 and Figure 9The diagram illustrates the relationship between the rotational speeds of the multiple rotors 221, 222, 223, and 224 that cause the UAV 200 to move forward and backward (in the x-direction). Specifically, to move the UAV 200 forward and backward, the fuselage 210 needs to be tilted forward and backward to change the direction of thrust. To achieve this, by slowing down the rotational speeds of the forward-facing third rotor 223 and fourth rotor 224 and increasing the speeds of the rearward-facing first rotor 221 and second rotor 222, the fuselage 210 of the UAV 200 will tilt forward. As a result, the thrust will be directed towards the rear of the fuselage 210, and the UAV 200 will move forward.

[0068] Figure 10 and Figure 11 The diagram illustrates the drone's left-right movement (y-axis direction) and rotation around the x-axis. Specifically, for the drone 200 to move left and right, the fuselage 210 needs to tilt left and right to change the direction of thrust. To achieve this, the speeds of the second rotor 222 and the fourth rotor 224 are reduced, while the rotational speeds of the first rotor 221 and the third rotor 223 are increased. This causes the fuselage 210 of the drone 200 to tilt to the right, resulting in thrust directed towards the left side of the fuselage 210, thus causing the drone 200 to move to the right.

[0069] Figure 12 This illustrates the concept of a drone moving along the z-axis. The vertical movement of the drone 200 is based on the same principle as hovering. If the rotational speeds of multiple rotors 221, 222, 223, and 224 are all the same, then increasing the rotational speeds of all rotors 221, 222, 223, and 224 by the same amount will increase the thrust, and the altitude will increase while the fuselage remains horizontal. Figure 12 a) Conversely, if the rotational speeds of multiple rotors 221, 222, 223, and 224 are reduced by the same amount, the thrust will decrease, and the altitude will decrease while the fuselage remains horizontal. Figure 12 b).

[0070] Figure 13 The diagram illustrates the UAV rotating around the z-axis. To make the UAV 200 rotate in the z-axis direction, the rotational speeds of multiple rotors rotating diagonally in the z-axis direction are reduced by a certain percentage, while the rotational speeds of the remaining rotors rotating in the opposite z-axis direction are increased by the same percentage. According to Newton's law of action and reaction, when the sum of the z-axis rotation vectors of the multiple rotors 221, 222, 223, and 224 is greater than 0, the fuselage rotates in the opposite z-axis direction based on the reaction force.

[0071] Figures 14 to 17This illustration shows a posture of the UAV 200 based on a second flight mode that differs from the first flight mode. In the 6-DOF flight mode, hovering, z-axis rotation, ascent, and descent can be achieved similarly to the aforementioned 4-DOF flight mode. This example primarily focuses on configurations that cannot be achieved in the 4-DOF flight mode.

[0072] Figure 14 The diagram illustrates the forward and backward movement of the drone. Specifically, to move the drone 200 forward and backward while it is hovering, multiple rotors 221, 222, 223, and 224 are tilted forward (meaning they tilt around the y-axis). The mechanism for keeping the fuselage 210 horizontal is similar to that during hovering.

[0073] Figure 15 The diagram illustrates the left-right movement of the drone. To enable the drone 200 to move left and right, while maintaining a hovering state, multiple rotors 221, 222, 223, and 224 are tilted to the left and right (meaning tilted while rotating around the x-axis). At this time, the mechanism for keeping the fuselage 210 horizontal is similar to that during hovering.

[0074] Figure 16 The fuselage section is shown rotating around the x-axis. That is, while hovering, in order to tilt the fuselage section 210 around the x-axis, the rotational speed of the second rotor 222 and the fourth rotor 224 on the right side is increased, while the rotational speed of the first rotor 221 and the third rotor 223 on the left side is decreased, and the fuselage section 210 of the UAV 200 will rotate around the x-axis.

[0075] When the fuselage 210 rotates, multiple rotors 221, 222, 223, and 224 also rotate in the same direction, changing the direction of thrust and causing the fuselage 210 to move. To compensate for this, the angles of multiple rotors 221, 222, 223, and 224 are changed by the same amount in the opposite direction to the rotation direction of the fuselage 210.

[0076] Figure 17 The fuselage section is shown rotating around the y-axis. That is, while hovering, in order to tilt the fuselage section 210 towards the y-axis, the rotational speed of the front third rotor 223 and fourth rotor 224 is increased, while the rotational speed of the rear first rotor 221 and second rotor 222 is decreased, and the fuselage section 210 of the UAV 200 will rotate around the y-axis.

[0077] and Figure 16 Similarly, when the fuselage 210 rotates, the multiple rotors 221, 222, 223, and 224 also rotate in the same direction to change the direction of thrust, thereby causing the fuselage 210 to move. To compensate for this, the angles of the multiple rotors 221, 222, 223, and 224 are changed by the same amount in the opposite direction to the rotation direction of the fuselage 210.

[0078] Figure 18 This diagram illustrates the control method of the drone 300 in 4DOF flight mode. In this example, it shows the aforementioned method where the motor angles of the drive motors 150 and 160 are not adjusted; similar to existing drones, the drone's flight mode is controlled solely by the rotational speed of the rotor (propeller). To ensure thrust, the drone fuselage 310 is tilted forward relative to the direction of travel. This tilt results in greater air resistance and downward pressure, reducing flight efficiency. In this situation, if a fixed camera is mounted on the fuselage 310, the camera's line of sight will sway due to the angle of the fuselage 310, making it difficult to capture images.

[0079] Figure 19 This is a diagram illustrating the control method of the UAV 300 in Horizontal Flight Mode, in which the present invention is applied.

[0080] The flight mode in this example keeps the fuselage 310 of the drone 300 level with the ground at all times, improving sensor performance and ensuring stable operation. There's no need to tilt the fuselage 310 in the forward direction to ensure thrust; only the rotors 321, 322, 323, and 324 are tilted in the forward direction. Because there's no tilting of the fuselage 310, air resistance is low, significantly improving flight efficiency. If a camera is installed on the fuselage 310, the camera's line of sight remains at a constant angle, allowing for stable filming. If there are passengers, the consistently level fuselage 310 greatly enhances the passenger experience.

[0081] Figure 20This diagram illustrates the control method of the UAV 300 in Efficient Flight Mode using the present invention. In this example, the flight mode is one in which the azimuth angle of the fuselage 310 of the UAV 300 is set in the same direction as the forward speed of the UAV 300, minimizing air resistance during forward movement. To this end, firstly, in order to make the UAV 300 fly according to the input values, the speeds and tilt angles of multiple rotors 321, 322, 323, and 324 are set. Within a pre-specified or controlled trajectory, the difference between the azimuth angle of the fuselage 310 and the forward speed (vector) of the UAV 300 is calculated. If the difference between the azimuth angle of the fuselage 310 and the forward speed of the UAV 300 exceeds a reference value, the tilt angles of the multiple rotors 321, 322, 323, and 324 are changed to reduce the difference between the azimuth angle of the fuselage 310 and the forward speed of the UAV 300, thereby minimizing the air resistance of the UAV 300. In other words, to ensure thrust, the angle of the fuselage 310 is aligned with the direction of travel, and the multiple rotors 321, 322, 323, and 324 are tilted in the direction of travel. Because the speed and attitude of the fuselage 310 are consistent, air resistance is minimized, maximizing flight efficiency. If a fixed camera is installed on the fuselage 310, the camera's line of sight will always remain in the same direction as the drone's movement speed, thus minimizing shooting constraints caused by shaking or directional changes, resulting in stable shooting effects. Ultimately, the most efficient and fastest maneuverability can be achieved.

[0082] Figure 21 This diagram illustrates the control method for the Focusing Flight Mode of the UAV 300 using this invention. In this example, the flight mode effectively handles various missions by fixing the azimuth of the fuselage 310 to a target specified by the operator. That is, regardless of the direction of movement of the UAV 300, the heading of the fuselage 310 is fixed to a specific target, making it suitable for performing various tasks. If equipped with firearms, it can shoot down targets and significantly increase the operating range of various sensors such as cameras, lidar, and radar. As for other applications, it can be used as the most suitable mode for image capture.

[0083] Figure 22This diagram illustrates the control method of the drone 300 in its Extreme Flight Mode, in which the present invention is applied. The flight mode in this example allows for free manipulation of the fuselage 310 angle regardless of the drone 300's forward direction, enabling the operator to control the drone for various tasks. Specifically, the control method includes the following steps: inputting an arbitrary angle mode with respect to the azimuth of the fuselage 310; inputting tilt angles of multiple rotors 321, 322, 323, and 324; and changing the tilt angles of the multiple rotors 321, 322, 323, and 324 according to the input tilt angles, thereby altering the azimuth of the fuselage 310. This allows for breaking free from fixed flight patterns and completing various tasks (drilling, drawing, carving, etc.), maximizing the drone's usability. Furthermore, it supports functions such as flipping more than 360 degrees in place and maximizes the enjoyment of operation by realizing the ultimate flight mode for drone operation. This mode is suitable for capturing dramatic footage.

[0084] The control method for a drone with multiple degrees of freedom flight modes described above is not limited to the configuration and methods of the above embodiments. Various modifications can be made to the embodiments by selectively combining all or part of the various embodiments.

Claims

1. A control method for a drone with multiple degrees of freedom flight modes, characterized in that, The drone includes: a fuselage, a battery installed, and its forward direction is set to the x-axis; The first rotor and the second rotor are arranged in the z-axis direction, and when viewed from the x-axis direction, they are positioned opposite each other with the fuselage as the center in the first position. The third and fourth rotors are arranged with their rotation axes aligned in the z-axis direction. When viewed from the x-axis direction, they are positioned opposite each other in the y-axis direction at the second position of the fuselage, wherein the x-axis, y-axis, and z-axis are perpendicular to each other. The first frame shaft, at the first position, is rotatably supported by the fuselage about a y1 axis parallel to the y axis, and at both ends, it supports the first rotor and the second rotor based on respective support shafts parallel to the x axis. The second frame axis, in the second position, is rotatably supported by the fuselage with the y2 axis parallel to the y axis as its center, and at both ends, it supports the third rotor and the fourth rotor based on each support axis parallel to the x axis. The third frame axis, relative to the first frame axis, is spaced apart in the z-axis direction based on a plurality of first rods, and moves based on a force parallel to the y-axis, such that the first rotor and the second rotor tilt about each axis parallel to the x-axis. The fourth frame axis, relative to the second frame axis, is spaced apart in the z-axis direction based on a plurality of second rods, and moves based on a force parallel to the y-axis, causing the third rotor and the fourth rotor to tilt about each axis parallel to the x-axis as a center; The first drive motor unit is connected via the first conversion mechanism unit and provides a force parallel to the y-axis to the third frame shaft and the fourth frame shaft; The second drive motor, connected via the second conversion mechanism, provides force to the first frame shaft and the second frame shaft, causing them to rotate about the y1 axis and the y2 axis respectively; and The control unit controls the first rotor, the second rotor, the third rotor, the fourth rotor, the first drive motor unit, and the second drive motor unit to achieve multiple flight modes. The control method includes the following steps: in order to make the UAV fly according to the input values, the speeds of the first rotor to the fourth rotor and the tilt angles of the first rotor to the fourth rotor are set; In the trajectory, calculate the difference between the azimuth angle of the fuselage and the forward speed of the UAV; and If the difference between the azimuth angle of the fuselage and the forward speed of the UAV exceeds a reference value, the tilt angles of the first to fourth rotors are adjusted to reduce the difference between the azimuth angle and the forward speed of the UAV. The plurality of flight modes include: a first flight mode in which both the first and second drive motors are completely stopped, and the speeds of the first to fourth rotors are controlled individually; and In the second flight mode, the first and second drive motors are activated independently, and the speeds of the first to fourth rotors are controlled independently. The first flight mode includes: Flight mode 1-1 causes the fuselage to tilt in the x-axis direction or move in the y-axis direction; Flight modes 1-2 cause the fuselage to tilt in the y-axis direction or move in the x-axis direction; Flight modes 1-3 cause the fuselage to rotate about the z-axis; and Flight modes 1-4 cause the fuselage to move in the z-axis direction. The second flight mode includes: Flight mode 2-1: The fuselage is kept horizontal, the first to the fourth rotors are tilted around axes parallel to the x-axis, and the fuselage is moved toward the y-axis. In the second-second flight mode, the fuselage is kept horizontal, the first to the fourth rotors are tilted around axes parallel to the y-axis, and the fuselage is moved in the direction of the y-axis. In the second and third flight modes, the fuselage is kept horizontal, and the speeds of the first to fourth rotors are controlled individually, causing the fuselage to rotate around the z-axis. Flight modes 2-4 keep the fuselage horizontal and control the speed of the first to fourth rotors individually to move the fuselage in the z-axis direction; Flight modes 2-5 cause the first to fourth rotors to rotate around axes parallel to the x-axis, and the fuselage to rotate relative to the x-axis; and Flight modes 2-6 cause the first to fourth rotors to rotate around axes parallel to the y-axis, and the fuselage to rotate relative to the y-axis.

2. The control method for a UAV with multi-degree-of-freedom flight modes according to claim 1, characterized in that, The control method further includes the following step: inputting the target pointing point; During the movement of the UAV according to the trajectory, in order to change the azimuth angle of the fuselage so that the fuselage continues to face the target pointing point, the tilt angle of the first rotor to the fourth rotor is changed.

3. The control method for a UAV with multi-degree-of-freedom flight modes according to claim 1, characterized in that, The control method further includes the following steps: inputting an arbitrary angle mode with respect to the azimuth angle of the fuselage; The tilt angle input from the first rotor to the fourth rotor; and The azimuth angle of the fuselage is changed by altering the tilt angle of the first rotor to the fourth rotor based on the input tilt angle.

4. The control method for a UAV with multi-degree-of-freedom flight modes according to claim 1, characterized in that, The second to fifth flight modes include: making each rotation axis of the first to the fourth rotor parallel to the z-axis, making the fuselage rotate relative to the x-axis, and maintaining an attitude of tilting relative to the ground.

5. The control method for a UAV with multi-degree-of-freedom flight modes according to claim 1, characterized in that, The second to sixth flight modes include: making the rotation axes of the first to the fourth rotors parallel to the z-axis, rotating the fuselage relative to the y-axis, and maintaining an attitude of tilting relative to the ground.

Images