阅读说明：本技术 一种无人直升机及其控制系统 (Unmanned helicopter and control system thereof ) 是由 丛闯闯 姜杨 吴成东 陈明非 姜文辉 闫志敏 孙昕 于 2021-11-05 设计创作，主要内容包括：本发明公开了一种无人直升机及其控制系统,包括控制器、主旋翼、用于操控主旋翼变距的第一操控机构、安装于无人直升机的两侧的机翼,两侧的机翼上均安装有推进机构；当无人直升机处于升降或悬停状态时,控制器控制无人直升机的两侧的推进机构进行差动,且使两侧的推进机构所产生的水平差动力矩与主旋翼旋转而产生的扭矩平衡。该控制系统,在实际应用过程中,当无人直升机处于升降或悬停状态时,通过控制器控制无人直升机的两侧的推进机构进行差动,且使两侧的推进机构所产生的水平差动力矩与主旋翼旋转而产生的扭矩平衡,从而能够使得无人直升机升降或者悬停时保持平衡。(The invention discloses an unmanned helicopter and a control system thereof, wherein the control system comprises a controller, a main rotor, a first control mechanism for controlling the variable pitch of the main rotor and wings arranged on two sides of the unmanned helicopter, wherein the wings on the two sides are provided with a propulsion mechanism; when the unmanned helicopter is in a lifting or hovering state, the controller controls the propulsion mechanisms on the two sides of the unmanned helicopter to perform differential motion, and the horizontal differential moment generated by the propulsion mechanisms on the two sides is balanced with the torque generated by the rotation of the main rotor. In the practical application process, when the unmanned helicopter is in a lifting or hovering state, the controller controls the propulsion mechanisms on the two sides of the unmanned helicopter to perform differential motion, and the horizontal differential moment generated by the propulsion mechanisms on the two sides is balanced with the torque generated by the rotation of the main rotor, so that the unmanned helicopter can keep balance when lifted or hovered.)

1. A control system of an unmanned helicopter comprises a controller, a main rotor (1), a first control mechanism (2) for controlling the variable pitch of the main rotor (1), and wings (3) arranged on two sides of the unmanned helicopter, and is characterized in that the wings (3) on the two sides are both provided with a propulsion mechanism (4); when the unmanned helicopter is in a lifting or hovering state, the controller controls the propulsion mechanisms (4) on the two sides of the unmanned helicopter to perform differential motion, and enables the horizontal differential moment generated by the propulsion mechanisms (4) on the two sides to be balanced with the torque generated by the rotation of the main rotor (1).

2. The control system of the unmanned helicopter of claim 1, characterized in that the propulsion mechanisms (4) on both sides are used for generating a propulsion force obliquely upward to the unmanned helicopter; when the unmanned helicopter is in a lifting or hovering state, the first control mechanism (2) controls the main rotor (1) to tilt backwards by a preset angle, and the horizontal backward partial pull force generated by the main rotor (1) is balanced with the resultant force of the horizontal forward partial push forces generated by the pushing mechanisms (4) on the two sides.

3. The control system of an unmanned helicopter of claim 2, wherein when said unmanned helicopter is in a vertical lift state, the pulling force of said main rotor (1) and the pushing force of said propulsion mechanism (4) satisfy the following relationship:

in the formula, F₁And F₂The thrust of the propulsion mechanism on two sides is respectively, T is the tension of the main rotor, theta is the inclination angle of the main rotor, beta is the installation angle of the propulsion mechanism, Q is the torque generated by the rotation of the main rotor, L is the wingspan of the helicopter, m is the weight of the unmanned helicopter, g is the gravity acceleration, and a is the expected acceleration of the unmanned helicopter in the vertical direction.

4. The control system of the unmanned helicopter of claim 3, further comprising detectors for monitoring the accelerations of the unmanned helicopter in all directions, wherein the controller performs closed-loop control adjustment of the main rotor (1) and the propulsion mechanism (4) in real time according to data detected by the detectors.

5. The control system of an unmanned helicopter of claim 1, characterized in that said propulsion mechanism (4) is at least one of a ducted fan, a propeller and a small turbine engine.

6. The control system of the unmanned helicopter of claim 1, further comprising a power mechanism (6) for driving the main rotor (1) to rotate, a position sensor for detecting the position of the blades of the main rotor (1), and a locking mechanism for locking the main rotor (1);

when the forward flying speed of the unmanned helicopter reaches a first preset speed, the controller controls the power mechanism (6) to drive the rotation speed of the main rotor (1) to be reduced along with the increase of the forward flying speed of the unmanned helicopter; when the forward flying speed of the unmanned helicopter reaches a second preset speed and the position sensor detects that two blades of the main rotor (1) point to the front and the rear of the unmanned helicopter respectively, the locking mechanism locks the main rotor; when the speed that unmanned helicopter flies forward is less than the second and predetermines speed, locking mechanism unblock main rotor (1), wherein, first predetermines speed and is less than the second and predetermines speed.

7. The control system of an unmanned helicopter of claim 6, wherein said first preset speed V₁And a second predetermined speed V₂Satisfies the relationship: v₁=kV₂Wherein the value of k is 0.8-0.9.

8. The control system of an unmanned helicopter of claim 7, wherein said second preset speed V₂The calculation method is as follows:

wherein m is the weight of the unmanned helicopter, g is the gravitational acceleration, rho is the atmospheric density, S is the wing area of the unmanned helicopter, C_lαThe slope of the lifting line of the wing airfoil is shown, and beta is the mounting angle of the wing.

9. The control system of the unmanned helicopter of claim 6, wherein the locking mechanism performs a locking action when the position sensor detects that two blades of the main rotor (1) rotate to a preset angle ahead of or behind the unmanned helicopter.

10. An unmanned helicopter comprising a control system, wherein the control system is the control system of the unmanned helicopter of any of claims 1-9.

Technical Field

The invention relates to the technical field of aviation, in particular to an unmanned helicopter and a control system thereof.

Background

The unmanned helicopter on the market at present adopts conventional configuration mostly, uses main rotor to provide required lifting force when all flight, leads to when unmanned helicopter goes up and down or suspends, and unmanned helicopter is difficult to keep balance.

In summary, how to solve the problem that the unmanned helicopter is difficult to keep balance when the unmanned helicopter is lifted or suspended becomes a technical problem to be solved urgently by those skilled in the art.

Disclosure of Invention

The invention aims to provide an unmanned helicopter and a control system thereof, and aims to solve the problem that the unmanned helicopter is difficult to keep balance when the unmanned helicopter is lifted or suspended.

In order to achieve the purpose, the invention provides a control system of an unmanned helicopter, which comprises a controller, a main rotor, a first control mechanism for controlling the variable pitch of the main rotor, and wings arranged on two sides of the unmanned helicopter, wherein the wings on the two sides are provided with a propulsion mechanism; when the unmanned helicopter is in a lifting or hovering state, the controller controls the propulsion mechanisms on the two sides of the unmanned helicopter to perform differential motion, and enables horizontal differential torque generated by the propulsion mechanisms on the two sides to be balanced with torque generated by rotation of the main rotor.

Preferably, the propulsion mechanisms on both sides are used for generating an upward thrust on the unmanned helicopter in an oblique direction; when the unmanned helicopter is in a lifting or hovering state, the first control mechanism controls the main rotor wing to tilt backwards by a preset angle, and the resultant force of the horizontal backward partial pulling force generated by the main rotor wing and the horizontal forward partial pushing force generated by the pushing mechanisms on the two sides is balanced.

Preferably, when the unmanned helicopter is in a vertical lifting state, the pulling force of the main rotor and the pushing force of the propelling mechanism satisfy the following relationship:

in the formula, F₁And F₂The thrust of the propulsion mechanism on two sides is respectively, T is the tension of the main rotor, theta is the inclination angle of the main rotor, beta is the installation angle of the propulsion mechanism, Q is the torque generated by the rotation of the main rotor, L is the wingspan of the helicopter, m is the weight of the unmanned helicopter, g is the gravity acceleration, and a is the expected acceleration of the unmanned helicopter in the vertical direction.

Preferably, the unmanned helicopter further comprises a detector for monitoring the acceleration of the unmanned helicopter in each direction, and the controller performs closed-loop control adjustment on the main rotor and the propulsion mechanism in real time according to data detected by the detector.

Preferably, the propulsion mechanism is at least one of a ducted fan, a propeller and a small turbine engine.

Preferably, the device further comprises a power mechanism for driving the main rotor to rotate, a position sensor for detecting the position of a blade of the main rotor, and a locking mechanism for locking the main rotor;

when the forward flying speed of the unmanned helicopter reaches a first preset speed, the controller controls the power mechanism to drive the rotation speed of the main rotor to reduce along with the increase of the forward flying speed of the unmanned helicopter; when the forward flying speed of the unmanned helicopter reaches a second preset speed and the position sensor detects that two blades of the main rotor respectively point to the front and the back of the unmanned helicopter, the locking mechanism locks the main rotor; when the speed that unmanned helicopter flown forward is less than the second and predetermines speed, locking mechanism unblock main rotor, wherein, first predetermined speed is less than the second and predetermines speed.

Preferably, the first preset speed V₁And a second predetermined speed V₂Satisfies the relationship: v₁=kV₂Wherein the value of k is 0.8-0.9.

Preferably, the second preset speed V₂The calculation method is as follows:

wherein m is the weight of the unmanned helicopter, g is the gravitational acceleration, rho is the atmospheric density, S is the wing area of the unmanned helicopter, C_lαThe slope of the lifting line of the wing airfoil is shown, and beta is the mounting angle of the wing.

Preferably, when the position sensor detects that two blades of the main rotor rotate to a preset angle in front of the unmanned helicopter or a preset angle behind the unmanned helicopter, the locking mechanism executes a locking action.

Compared with the introduction content of the background technology, the control system of the unmanned helicopter comprises a controller, a main rotor, a first control mechanism for controlling the variable pitch of the main rotor and wings arranged on two sides of the unmanned helicopter, wherein the wings on the two sides are provided with propulsion mechanisms; when the unmanned helicopter is in a lifting or hovering state, the controller controls the propulsion mechanisms on the two sides of the unmanned helicopter to perform differential motion, and the horizontal differential moment generated by the propulsion mechanisms on the two sides is balanced with the torque generated by the rotation of the main rotor. In the practical application process, when the unmanned helicopter is in a lifting or hovering state, the controller controls the propulsion mechanisms on the two sides of the unmanned helicopter to perform differential motion, and the horizontal differential moment generated by the propulsion mechanisms on the two sides is balanced with the torque generated by the rotation of the main rotor, so that the unmanned helicopter can keep balance when lifted or hovered.

In addition, the invention also provides an unmanned helicopter, which comprises a control system, wherein the control system is the control system of the unmanned helicopter described in any scheme above, and the control system of the unmanned helicopter has the technical effects, so the unmanned helicopter with the control system also has the corresponding technical effects, and the details are not repeated herein.

Drawings

Fig. 1 is a schematic overall structural diagram of an unmanned helicopter provided in an embodiment of the present invention;

fig. 2 is a schematic partial structural view of an unmanned helicopter provided in an embodiment of the present invention;

FIG. 3 is a schematic view of a partially cut-away structure of an unmanned helicopter provided in an embodiment of the present invention;

FIG. 4 is a schematic pitch angle diagram of a leading side blade provided in accordance with an embodiment of the present invention;

FIG. 5 is a schematic pitch angle diagram of a trailing blade according to an embodiment of the present invention;

fig. 6 is a schematic diagram illustrating a corresponding relationship between a rotation speed of a main rotor and a forward flying speed of an unmanned helicopter according to an embodiment of the present invention;

fig. 7 is a schematic diagram illustrating a corresponding relationship between a pitch angle of a main rotor and a forward flying speed of an unmanned helicopter according to an embodiment of the present invention;

FIG. 8 is a schematic diagram illustrating a relationship between a lift control ratio of a wing and a forward flying speed of an unmanned helicopter according to an embodiment of the present invention;

FIG. 9 is a schematic view of an installation angle of a wing provided by an embodiment of the invention;

fig. 10 is a schematic structural view of positions of a forward side blade and a backward side blade of a main rotor according to an embodiment of the present invention;

fig. 11 is a schematic structural view of the position of the blades of the main rotor directly in front and behind according to the embodiment of the present invention.

In the context of figures 1-11,

the main rotor wing 1, the forward side blade 1a, the backward side blade 1b, the first control mechanism 2, the wing 3, the main wing 31, the aileron 32, the propulsion mechanism 4, the empennage 5, the horizontal empennage 51, the elevator 51a, the vertical empennage 52, the rudder 52a, the power mechanism 6, the driving motor 61, the transmission mechanism 62, the first sensor 7 and the second sensor 8.

Detailed Description

The invention provides an unmanned helicopter and a control system thereof, and aims to solve the problem that the unmanned helicopter is difficult to keep balance when the unmanned helicopter is lifted or suspended.

In order to make those skilled in the art better understand the technical solutions provided by the present invention, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1 to 11, an embodiment of the present invention provides a control system of an unmanned helicopter, including a controller, a main rotor 1, a first control mechanism 2 for controlling the pitch of the main rotor 1, and wings 3 mounted on two sides of the unmanned helicopter, wherein the wings 3 on the two sides are both provided with a propulsion mechanism 4; when the unmanned helicopter is in a lifting or hovering state, the controller controls the propulsion mechanisms 4 on the two sides of the unmanned helicopter to perform differential motion, and makes the horizontal differential moment generated by the propulsion mechanisms 4 on the two sides balanced with the torque generated by the rotation of the main rotor 1.

In the practical application process, when the unmanned helicopter is in a lifting or hovering state, the controller controls the propulsion mechanisms on the two sides of the unmanned helicopter to perform differential motion, and the horizontal differential moment generated by the propulsion mechanisms on the two sides is balanced with the torque generated by the rotation of the main rotor, so that the unmanned helicopter can keep balance when lifted or hovered.

It should be noted that, as those skilled in the art will understand, the term "differential" in the aforementioned "controlling the propulsion mechanisms on both sides of the unmanned helicopter to perform differential" means that the propulsion forces generated by the propulsion mechanisms on both sides of the unmanned helicopter do not move in an equal manner, and then the horizontal differential torque that can be generated is balanced with the torque generated by the rotation of the main rotor 1.

In some specific embodiments, the propulsion mechanisms 4 on both sides are used for generating a thrust force obliquely upwards on the unmanned helicopter; when the unmanned helicopter is in a lifting or hovering state, the first control mechanism 2 controls the main rotor 1 to tilt backwards by a preset angle, and the resultant force of the horizontal backward partial pulling force generated by the main rotor 1 and the horizontal forward partial pushing force generated by the pushing mechanisms 4 on the two sides is balanced. Because the general installation angle of the propulsion mechanism on the wings on both sides can adopt the oblique upward direction, the forward thrust generated by the propulsion mechanism is balanced by the horizontal backward partial pull force generated by the main rotor wing, so that the stress balance of the unmanned helicopter in a lifting or hovering state in a horizontal plane can be ensured.

In a further embodiment, when the unmanned helicopter is in a vertical lifting state, the pulling force of the main rotor 1 and the pushing force of the pushing mechanism 4 should satisfy the following relationship:

in the formula, F₁And F₂The thrust of the propulsion mechanisms on the two sides, T is the tension of the main rotor, theta is the inclination angle of the main rotor, beta is the installation angle of the propulsion mechanisms, Q is the torque generated by the rotation of the main rotor, L is the wingspan of the helicopter, m is the weight of the unmanned helicopter, g is the gravity acceleration, and a is the expected acceleration of the unmanned helicopter in the vertical direction. Wherein, when the unmanned helicopter is in a hovering state, a = g.

In a further embodiment, the control system may further include a detector for monitoring the accelerations of the unmanned helicopter in all directions, and the controller performs closed-loop control adjustment on the main rotor 1 and the propulsion mechanism 4 in real time according to data detected by the detector, so as to calculate the required operating parameters of the propulsion mechanism 4 and the main rotor 1 with the goal of minimizing the power consumed by the propulsion mechanism 4, and performs closed-loop control by monitoring the accelerations of the unmanned helicopter in all directions through the detector and adjusting the main rotor 1 and the propulsion mechanism 4 in real time.

It should be noted that, in general, the propulsion mechanism 4 may be specifically configured by one or a combination of a plurality of ducted fans, propellers, and small turbine engines, and during the practical application, the propulsion mechanism may be specifically configured according to the specific model, which is not limited herein more specifically.

In some specific embodiments, the control system further comprises a power mechanism 6 which is supposed to drive the main rotor 1 to rotate, a position sensor for detecting the position of the blades of the main rotor 1, and a locking mechanism for locking the main rotor 1; when the forward flying speed of the unmanned helicopter reaches a first preset speed, the controller controls the power mechanism 6 to drive the rotation speed of the main rotor 1 to be reduced along with the increase of the forward flying speed of the unmanned helicopter; when the forward flying speed of the unmanned helicopter reaches a second preset speed and the position sensor detects that two blades of the main rotor 1 point to the front and the back of the unmanned helicopter respectively, the locking mechanism locks the main rotor; when the forward flying speed of the unmanned helicopter is lower than a second preset speed, the locking mechanism unlocks the main rotor wing 1, wherein the first preset speed is lower than the second preset speed. Because along with unmanned helicopter flying speed's increase, reach first predetermined speed after, when flying speed reached second predetermined speed, the rotation rate of main rotor had reduced to lower rotation rate this moment, and rethread locking mechanical system carries out the locking operation this moment, can effectively avoid high-speed rotor suddenly to lock and die to produce too big impact. When the aircraft is in a high-speed flight state, namely the speed exceeds the second preset speed, the propulsion mechanism provides the main power for forward flight, and the lift force of the aircraft is mainly provided by the wings.

It should be noted that the locking mechanism may be specifically realized by a static locking function of the driving motor 61 of the power mechanism 6, or by a mechanical structure in the transmission device 62, which belongs to the conventional technology and is not limited herein.

Generally, the first predetermined speed V₁And a second predetermined speed V₂Satisfies the relationship: v₁=kV₂Wherein the value of k is 0.8-0.9. Wherein the second preset speed V₂The calculation method specifically comprises the following steps:

wherein m is the weight of the unmanned helicopter, g is the gravitational acceleration, rho is the atmospheric density, S is the wing area of the unmanned helicopter, C_lαThe slope of the lifting line of the wing airfoil is shown, and beta is the mounting angle of the wing.

In some more specific embodiments, considering that a certain buffer is needed for completing the locking action of the main rotor, when the position sensor detects that the two blades of the main rotor 1 rotate to a preset angle ahead of the unmanned helicopter or a preset angle behind the unmanned helicopter, the locking mechanism performs the locking action, wherein the preset angle ahead of the unmanned helicopter or the preset angle behind the unmanned helicopter may specifically be 1 ° to 5 °, and during the actual application process, the corresponding preset angle may be selected and configured according to the actual requirement, which is not limited herein in more detail.

In some more specific embodiments, the wing 3 may specifically include a main wing 31, an aileron 32 mounted to the main wing 31 in a longitudinally deflectable manner, and a second steering mechanism for steering the longitudinal deflection angle of the aileron 32; when the forward flying speed of the unmanned helicopter reaches a second preset speed, the controller is used for controlling the first control mechanism 2 to reduce the pitch angle of the main rotor wing 1 to zero, and simultaneously controlling the second control mechanism to adjust the longitudinal deflection angle of the aileron 32, so that the overall lift force of the unmanned helicopter is equal to the gravity of the unmanned helicopter. In the practical application process, when the forward flying speed of the unmanned helicopter reaches a second preset speed, the controller controls the first control mechanism to reduce the pitch angle of the main rotor to zero, at the moment, the main rotor does not generate lift force, and the controller controls the second control mechanism to adjust the longitudinal deflection angle of the aileron to realize that the overall lift force of the unmanned helicopter is equal to the gravity of the unmanned helicopter, so that the influence of the unbalanced aerodynamic force of the main rotor on the flying of the unmanned helicopter can be reduced; meanwhile, the included angle between the rotating plane of the main rotor and the flying direction can be ensured to be 0 degree in the horizontal flying process, so that the resistance and the interference of the main rotor to the forward flying of the unmanned helicopter are reduced, and the flying speed of the unmanned helicopter is promoted.

In some specific embodiments, the unmanned helicopter further includes a tail 5, and the tail 5 may specifically include a horizontal tail 51 and a vertical tail 52, wherein the horizontal tail 51 may be provided with an elevator 51a for adjusting a lifting moment of the horizontal tail 51, and the vertical tail 52 is provided with a rudder 52a for adjusting a guiding direction of the vertical tail 52; when the forward flying speed of the unmanned helicopter reaches a second preset speed, the controller controls the second control mechanism to adjust the longitudinal deflection angle of the ailerons 32 so as to raise the lifting moment of the wings 3, and simultaneously controls the elevators 51a to raise the lifting moment of the horizontal tail wing, so that the overall lifting force of the unmanned helicopter is kept equal to the gravity of the unmanned helicopter. By designing the horizontal tail wing and the elevator, the lift force control can be realized by matching with the wings, and the problem of insufficient lift force regulation of the ailerons can be avoided. Meanwhile, the control of the flight direction can be facilitated through the vertical tail fin and the rudder.

In some specific embodiments, when the forward flying speed of the unmanned helicopter reaches a first preset speed and does not reach a second preset speed, the controller controls the first control mechanism 2 to decrease the pitch angle of the main rotor 1, and controls the second control mechanism to adjust the longitudinal deflection angle of the aileron 32, so that the overall lift generated by the main rotor 1 and the wings 3 is equal to the gravity of the unmanned helicopter, wherein the first preset speed is less than the second preset speed. By the control mode, the pitch angle of the main rotor wing is adjusted to zero, a transition stage is achieved, meanwhile, transition is achieved by adjusting the longitudinal deflection angle of the ailerons on the wings, and the situation that flight is unstable due to overlarge pitch angle adjustment or overlarge longitudinal deflection angle is avoided.

In a further embodiment, when the first control mechanism 2 controls the pitch angle of the main rotor 1 to decrease, the controller controls the first control mechanism 2 to perform cyclic pitch change on the main rotor 1 and maintain the pitch angle of the forward-moving blade 1a on the main rotor 1 lower than the pitch angle of the backward-moving blade 1b on the main rotor 1, so that the lift force of the forward-moving blade 1a is balanced with the lift force of the backward-moving blade 1 b. Through the adjusting mode, the stability of the lifting force of the two sides of the main rotor wing can be enhanced, and the unstable flight caused by the loss of the balance of the left side and the right side is avoided.

In some more specific embodiments, when the first control mechanism 2 controls the pitch angle of the main rotor 1 to decrease, the following method can be specifically adopted: the pitch angle of the trailing blade 1b is kept at a preset maximum value and the pitch angle of the leading blade 1a is reduced, mainly in the case of a gradual acceleration of the forward flight speed.

Note that the pitch angle of the forward blade 1a and the pitch angle of the backward blade 1b may be obtained specifically according to the following formulas:

wherein s is the rotor solidity of the main rotor, θ₀Is a fixed geometric parameter of the rotor; c is the slope of the lifting line of the airfoil of the blade; v is the flight speed of the unmanned helicopter; omega is the angular speed of the main rotor rotation; r is the main rotor radius; ρ is the atmospheric density; t is the pulling force generated by the main rotor; v. of_iThe air flow speed for blowing the main rotor wing downwards; theta₁Is the pitch angle of the advancing side blade; theta₂For trailing side bladesThe pitch angle.

Wherein the preset maximum value of the pitch angle of the trailing side blades 1b is typically preferably 15-20.

It should be noted that the unmanned helicopter should also be equipped with various sensors to achieve various detection requirements, for example, a first sensor 7 (specifically, a hall element) may be installed at the wing, and a longitudinal deflection angle of an aileron on the wing may be detected by the first sensor; a second sensor 8 (which may be specifically an optical sensor) may be provided on the top of the body.

In addition, the invention also provides an unmanned helicopter, which comprises a control system, wherein the control system is the control system of the unmanned helicopter described in any scheme above, and the control system of the unmanned helicopter has the technical effects, so the unmanned helicopter with the control system also has the corresponding technical effects, and the details are not repeated herein.

The unmanned helicopter and the control system thereof provided by the invention are described in detail above. It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

It is also noted that, in this document, terms such as "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in an article or device that comprises the element.

The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the core concepts of the present invention. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.