Variable type machine arm and four-rotor aircraft with up and down staggered blades and control method thereof

Abstract

The present application relates to a variable arm and four-rotor aircraft with up-down staggered blades and a control method thereof, comprising two cross-arranged arms, the cross centers of which are rotationally connected with a linear motor, the upper ends of the two ends of the upper arm are fixedly provided with upper rotating motors, the lower ends of the two ends of the lower arm are fixedly connected with lower rotating motors, the upper rotating motor and the lower rotating motor driving end are connected with rotors; the primary of the linear motor is located between the two arms, and the end thereof extends a guide rail for linear motion of the secondary of the linear motor, the two sides of the secondary of the linear motor extend reverse L-shaped rods and are hinged with the two arms, the two arms move linearly on the guide rail with the secondary of the linear motor and move towards each other or move away from each other around the hinge point, the upper arm is rotationally connected with a body above the middle part, the body is provided with a power supply for power supply, the aircraft adjusts the included angle between the arms to adapt to narrow environment, and has the characteristics of high flexibility and strong environmental adaptability.

Description

Technical Field

[0001] This invention belongs to the field of small aircraft and rotor aerodynamics technology, and particularly relates to a quadcopter with variable-shaped arms and vertically offset blades and its control method. Background Technology

[0002] Unmanned aerial vehicles (UAVs) can take off and land vertically and hover. Due to these characteristics, they are used for tasks such as surveillance, search and rescue, and reconnaissance. They reduce the risk of human exposure in environments with chemical contamination and in confined spaces. They can perform necessary tasks in places such as sewers, caves, and collapsed buildings, and have significant applications in many fields. However, traditional UAVs often struggle to perform effectively in narrow terrain; therefore, a quadcopter UAV capable of changing its arm angle was designed. Furthermore, considering the changes in the dynamic equations caused by the change in arm angle, a flight control method adapted to this aircraft was proposed. Summary of the Invention

[0003] The purpose of this invention is to overcome the insufficient control performance in the prior art and to provide a quadcopter with variable arms and staggered blades and its control method. It achieves efficient control of the angle between the arms to adapt to narrow environments, and through special blade settings, it can ensure that the blades do not interfere with each other after the cantilever rotates, thus achieving high flexibility.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: a quadcopter with variable-sized arms and staggered blades, comprising two arms arranged in a cross configuration, each cross center rotatably connected to a linear motor. An upper rotary motor is fixed to the upper part of both ends of the upper arm, and a lower rotary motor is fixed to the lower part of both ends of the lower arm. Rotors are connected to the drive ends of both the upper and lower rotary motors. The primary winding of the linear motor is located between the two arms on the upper and lower sides, and its end extends a guide rail for the linear movement of the secondary winding of the linear motor. Opposite L-shaped rods extend from both sides of the secondary winding of the linear motor and are hinged to the two arms. The two arms move linearly along the guide rails as the secondary winding of the linear motor moves, moving towards each other or away from each other around the hinge point. An airframe is rotatably connected above the middle of the upper arm, and a power supply for powering the airframe is provided on the airframe.

[0005] Furthermore, the upper arm is called the upper arm, and the lower arm is called the lower arm. The upper arm is hinged to an L-shaped rod extending upward vertically, and the lower arm is hinged to an L-shaped rod extending downward vertically.

[0006] Furthermore, the upper rotating motor and the lower rotating motor rotate in opposite directions, that is, among the four rotors of the quadcopter, the two adjacent rotors rotate in opposite directions, to avoid the reaction force generated on the motor during rotation causing the motor to rotate in the opposite direction, so that the aircraft can spin.

[0007] Furthermore, the power source consists of multiple battery packs.

[0008] The control method for a quadcopter with variable-arm and vertically offset blades is as follows:

[0009] First, establish an Earth coordinate system. This is used to study the state of an aircraft relative to the ground, ignoring the curvature of the Earth, and using the takeoff position of the UAV as the origin of the coordinate system. An axis perpendicular to the ground and pointing downwards is specified in the horizontal plane. The axis is then determined using the right-hand rule. axis;

[0010] The three-dimensional position of the drone can be represented as follows:

[0011]

[0012] And according to the definition of Euler angles, where The pitch angle, For roll angle, Yaw angle:

[0013]

[0014] Set the body coordinate system The origin Take it at the body's center of gravity. shaft and If the axes are in the same direction, the same applies to the other axes.

[0015] Where u is the velocity of the machine along the x-axis, v is the velocity of the machine along the y-axis, and w is the velocity of the machine along the z-axis:

[0016]

[0017] Where p is the roll rate, q is the pitch rate, and r is the yaw rate.

[0018]

[0019] The thrust generated by a single rotor can be calculated using the following formula:

[0020]

[0021]

[0022] Indicates the first The rotational speed of each rotor, in units of ;

[0023] RPM is the number of rotations per minute of the rotor, and pitch is the rotor pitch in inches. Where k is the air velocity and k is the lift coefficient;

[0024] Because the angle between the aircraft's arms can change, it is necessary to specify the angle between the arms and... The angle between the positive axis and the positive axis is ;

[0025] Create a model of tension and torque:

[0026]

[0027] in The total thrust generated by the rotor. For the rotor in The torque generated by the direction, For the rotor in The torque generated by the direction, For the rotor in The torque generated in the direction; From the rotor center to The distance between the axes, where d is the drag coefficient;

[0028] Because the angle between the aircraft's arms changes, the overall moment of inertia of the aircraft also changes accordingly; since the connection point between the two arms is the center point, the arms are considered as uniform cantilever arms, and the mass of each cantilever arm is assumed to be... The cantilever length is The weight of each set of upper / lower rotating motors and rotor is The body and battery pack The moment of inertia of the shaft is The body and battery pack The moment of inertia of the shaft is

[0029] Therefore, the moment of inertia of the entire machine can be obtained as:

[0030]

[0031]

[0032] Changes in the arm angle will not affect the overall machine's performance. Moment of inertia

[0033] Let the mass of the entire aircraft be... ;

[0034] Combining the classic transformation matrix between the machine coordinate system and the Earth coordinate system:

[0035]

[0036] achievable

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] To facilitate calculations and improve processor response speed, the dynamic model of the quadcopter is linearized:

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062] Therefore, a longitudinal state-space model of the organism can be derived:

[0063]

[0064]

[0065] And the lateral state-space model of the body:

[0066]

[0067]

[0068] Compared with the prior art, the present invention has the following advantages: the variable arm and the staggered blades of the quadcopter can control the rotation of the arm to adapt to narrow environments, and the special blade arrangement can ensure that the blades do not interfere with each other after the cantilever rotates. It has the characteristics of high flexibility, strong environmental adaptability and easy commercialization. Attached Figure Description

[0069] Figure 1 This is a schematic diagram illustrating the structure of an embodiment of the present invention;

[0070] Figure 2 This is a schematic diagram of the structure of the two arms when the included angle is 45° according to an embodiment of the present invention;

[0071] Figure 3 This is a front view of an embodiment of the present invention;

[0072] Figure 4 This is a bottom view of an embodiment of the present invention;

[0073] Figure 5 This is a schematic diagram of the structure of a linear motor in an embodiment of the present invention;

[0074] Figure 6 This is a schematic diagram of the rotor distribution according to an embodiment of the present invention.

[0075] In the diagram: 1-arm, 2-upper rotating motor, 3-lower rotating motor, 4-rotor, 5-primary of linear motor, 6-secondary of linear motor, 7-guide rail, 8-L-shaped rod, 9-body, 10-battery, 11-baffle, 12-upper arm, 13-lower arm, 14-linear motor. Detailed Implementation

[0076] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0077] like Figures 1-6As shown, the quadcopter with variable arms and staggered blades provided by the present invention includes two cross-shaped arms 1, each with its center rotatably connected to a linear motor 14. An upper rotating motor 2 is fixed to the upper part of both ends of the upper arm, and a lower rotating motor 3 is fixed to the lower part of both ends of the lower arm. Both the upper and lower rotating motors are connected to rotors 4, effectively avoiding rotor interference that may occur when the angle between the arms decreases. The primary motor 5 is located between the two arms on the upper and lower sides, and its end extends a guide rail 7 for the linear movement of the secondary motor 6. L-shaped rods 8 extend from both sides of the secondary motor, respectively, and are hinged to the two arms. The two arms move linearly along the guide rail as the secondary motor moves, moving towards each other or away from each other around the hinge point. A body 9 is rotatably connected above the middle of the upper arm, and a power supply for powering the body is provided on the body.

[0078] In this embodiment of the invention, the upper arm is called the upper arm 12, and the lower arm is called the lower arm 13. The upper arm is hinged to an L-shaped rod extending upward vertically, and the lower arm is hinged to an L-shaped rod extending downward vertically.

[0079] In this embodiment of the invention, a baffle 11 is fixed at the outer end of the guide rail to prevent the secondary winding 6 of the linear motor from detaching from the guide rail 7 during movement.

[0080] In this embodiment of the invention, the upper rotating motor and the lower rotating motor rotate in opposite directions. That is, among the four rotors of the quadcopter, the rotation directions of two adjacent rotors are opposite, so as to avoid the reaction force generated on the motor during rotation causing the motor to rotate in the opposite direction, so that the aircraft can spin.

[0081] In this embodiment of the invention, the power supply is composed of multiple battery packs, each consisting of multiple batteries 10 evenly distributed on the fuselage. In order to supply power to the rotor motor and the linear motor, four interfaces are provided at the bottom of the fuselage, and the batteries will be vertically connected to the lower side of the fuselage. This saves space on the fuselage and also constrains the movement of the cantilever to prevent the angle between the cantilever from being too large.

[0082] In this embodiment of the invention, a linear motor is provided between the two robotic arms. The primary of the linear motor is fixed, but the secondary can move on the guide rail after being charged. The secondary is closely connected to the two robotic arms. When the secondary moves forward, it will cause the included angle of the robotic arms to decrease.

[0083] In this embodiment of the invention, since the fuselage and arms undergo active deformation, the dynamic model of the fuselage needs to be updated in real time. Therefore, the complex dynamic model is linearized, which ensures computational accuracy while accelerating the processor's response speed. This enables the related control of the fuselage's lateral and longitudinal flight.

[0084] In this embodiment of the invention, the quadcopter with variable arms and vertically offset blades also includes a body for carrying computing hardware, sensors and other necessary circuit components, as well as providing interfaces for batteries and other components.

[0085] In this embodiment of the invention, the control method for a quadcopter with variable arms and vertically offset blades is performed according to the following steps:

[0086] First, establish an Earth coordinate system. This is used to study the state of an aircraft relative to the ground, ignoring the curvature of the Earth, and using the takeoff position of the UAV as the origin of the coordinate system. An axis perpendicular to the ground and pointing downwards is specified in the horizontal plane. The axis is then determined using the right-hand rule. axis;

[0087] The three-dimensional position of the drone can be represented as follows:

[0088]

[0089] And according to the definition of Euler angles, where The pitch angle, For roll angle, Yaw angle:

[0090]

[0091] Set the body coordinate system The origin Take it at the body's center of gravity. shaft and If the axes are in the same direction, the same applies to the other axes.

[0092] Where u is the velocity of the machine along the x-axis, v is the velocity of the machine along the y-axis, and w is the velocity of the machine along the z-axis:

[0093]

[0094] Where p is the roll rate, q is the pitch rate, and r is the yaw rate.

[0095]

[0096] The thrust generated by a single rotor can be calculated using the following formula:

[0097]

[0098]

[0099] Indicates the first The rotational speed of each rotor, in units of ;

[0100] RPM is the number of rotations per minute of the rotor, and pitch is the rotor pitch in inches. Where k is the air velocity and k is the lift coefficient;

[0101] Because the angle between the aircraft's arms can change, it is necessary to specify the angle between the arms and... The angle between the positive axis and the positive axis is ;

[0102] Create a model of tension and torque:

[0103]

[0104] in The total thrust generated by the rotor. For the rotor in The torque generated by the direction, For the rotor in The torque generated by the direction, For the rotor in The torque generated in the direction; From the rotor center to The distance between the axes, where d is the drag coefficient;

[0105] Because the angle between the aircraft's arms changes, the overall moment of inertia of the aircraft also changes accordingly; since the connection point between the two arms is the center point, the arms are considered as uniform cantilever arms, and the mass of each cantilever arm is assumed to be... The cantilever length is The weight of each set of upper / lower rotating motors and rotor is The body and battery pack The moment of inertia of the shaft is The body and battery pack The moment of inertia of the shaft is

[0106] Therefore, the moment of inertia of the entire machine can be obtained as:

[0107]

[0108]

[0109] Changes in the arm angle will not affect the overall machine's performance. Moment of inertia

[0110] Let the mass of the entire aircraft be... ;

[0111] Combining the classic transformation matrix between the machine coordinate system and the Earth coordinate system:

[0112]

[0113] achievable

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126] To facilitate calculations and improve processor response speed, the dynamic model of the quadcopter is linearized:

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139] Therefore, a longitudinal state-space model of the organism can be derived:

[0140]

[0141]

[0142] And the lateral state-space model of the body:

[0143]

[0144]

[0145] This invention is not limited to the preferred embodiment described above. Anyone inspired by this invention can derive various other forms of quadcopter aircraft with variable arms and vertically offset blades, and their control methods. All equivalent variations and modifications made within the scope of the claims of this invention should be considered within the scope of this invention.

Claims

1. A control method for a quadcopter with variable-width arms and staggered blades, the quadcopter comprising two arms arranged crosswise, each crosswise and rotatably connected to a linear motor at its center; an upper rotary motor is fixedly mounted on the upper part of both ends of the upper arm, and a lower rotary motor is fixedly mounted on the lower part of both ends of the lower arm; rotors are connected to the drive ends of the upper and lower rotary motors; the primary of the linear motor is located between the two arms and its end extends a guide rail for linear motion of the secondary of the linear motor; L-shaped rods extending in opposite directions from both sides of the secondary of the linear motor are hinged to the two arms; the two arms move linearly towards each other or away from each other around the hinge point as the secondary of the linear motor moves linearly on the guide rail; an airframe is rotatably connected above the middle of the upper arm, and a power supply for power supply is provided on the airframe; Its features are: The control method is performed according to the following steps: First, establish an Earth coordinate system. This is used to study the state of an aircraft relative to the ground, ignoring the curvature of the Earth, and using the takeoff position of the UAV as the origin of the coordinate system. An axis perpendicular to the ground and pointing downwards is specified in the horizontal plane. The axis is then determined using the right-hand rule. axis; The three-dimensional position of the drone can be represented as follows: And according to the definition of Euler angles, where The pitch angle, For roll angle, Yaw angle: Set the body coordinate system The origin Take it at the body's center of gravity. shaft and If the axes are in the same direction, the same applies to the other axes. Where u is the velocity of the machine along the x-axis, v is the velocity of the machine along the y-axis, and w is the velocity of the machine along the z-axis: Where p is the roll rate, q is the pitch rate, and r is the yaw rate. The thrust generated by a single rotor can be calculated using the following formula: Indicates the first The rotational speed of each rotor, in units of ; RPM is the number of rotations per minute of the rotor, and pitch is the rotor pitch in inches. Where k is the air velocity and k is the lift coefficient; Because the angle between the aircraft's arms can change, it is necessary to specify the angle between the arms and... The angle between the positive axis and the positive axis is ; Create a model of tension and torque: in The total thrust generated by the rotor. For the rotor in The torque generated by the direction, For the rotor in The torque generated by the direction, For the rotor in The torque generated in the direction; From the rotor center to The distance between the axes, where d is the drag coefficient; Because the angle between the aircraft's arms changes, the overall moment of inertia of the aircraft also changes accordingly; since the connection point between the two arms is the center point, the arms are considered as uniform cantilever arms, and the mass of each cantilever arm is assumed to be... The cantilever length is The weight of each set of upper / lower rotating motors and rotor is... The body and battery pack The moment of inertia of the shaft is The body and battery pack The moment of inertia of the shaft is Therefore, the moment of inertia of the entire machine can be obtained as: Changes in the arm angle will not affect the overall machine's performance. Moment of inertia Let the mass of the entire aircraft be... ; Combining the classic transformation matrix between the body coordinate system and the Earth coordinate system: achievable To facilitate calculations and improve processor response speed, the dynamic model of the quadcopter is linearized: Therefore, a longitudinal state-space model of the organism can be derived: And the lateral state-space model of the body:

2. The control method for a quadcopter with variable arms and vertically offset blades according to claim 1, characterized in that: The upper arm is the upper arm, and the lower arm is the lower arm. The upper arm is hinged to an L-shaped rod extending upward vertically, and the lower arm is hinged to an L-shaped rod extending downward vertically.

3. The control method for a quadcopter with variable arms and vertically offset blades according to claim 1, characterized in that: The upper rotating motor and the lower rotating motor rotate in opposite directions.

4. The control method for a quadcopter with variable arms and vertically offset blades according to claim 1, characterized in that: The power source consists of multiple battery packs.

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