Unmanned helicopter suspension anti-swing method and system

Abstract

The invention relates to an unmanned helicopter suspension anti-swing method and system, belongs to the technical field of unmanned aerial vehicle control, and solves the problems that an existing unmanned aerial vehicle suspension flight system is high in dependence on load mass, limited in application range and low in control precision during control. The method comprises the following steps: respectively obtaining three-axis attitude motion information of a detacher adapter plate and three-axis attitude motion information of a hanging box; on the basis of the three-axis attitude motion information of the detacher adapter plate and the three-axis attitude motion information of the hanging box, calculating to obtain swing data of the hanging box relative to the detacher adapter plate; based on the swing data, calculating to obtain an anti-swing horizontal acceleration; and based on the anti-swing horizontal acceleration, calculating to obtain an anti-swing angle output by the anti-swing controller, and inputting the anti-swing angle and the current attitude angle and the target attitude angle of the unmanned helicopter into an attitude controller to control the unmanned helicopter. The swing is quickly eliminated, the flight stability is improved, the dependence on specific conditions is reduced, and the system adaptability and reliability are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle control, and in particular to a method and system for hanging and eliminating sway of an unmanned helicopter. Background Art

[0002] In recent years, UAV technology has developed rapidly in many application fields, such as reconnaissance and exploration, agricultural plant protection, emergency rescue, power line inspection, post-disaster assessment and other fields, all of which play an important role. Among them, the transportation of heavy-load materials is one of the most urgent application scenarios for unmanned helicopter missions. Heavy-load cargo is generally large in size and difficult to store directly in the fuselage transport cabin or under the belly of the fuselage. Therefore, hanging flight is the main mode of transportation for heavy-loaded unmanned helicopters. Similar to transportation systems such as bridge cranes, how to transport the suspended load to the designated target location smoothly, safely, efficiently and accurately is the key to the development of unmanned helicopter hanging control systems.

[0003] In the existing control design, many assumptions and simplifications are made on the dynamic characteristics of the controlled object. For example, the controller is designed based on the assumption that the load swing angle is small enough. However, in actual situations, it should be considered that when the swing angle fluctuates greatly, necessary feedback control is required to ensure the stability of the system. Other control methods are based on the condition that the mass of the suspended load is known, but in actual applications, there are situations where the load mass changes. When the load mass changes, the control accuracy will decrease. Summary of the invention

[0004] In view of the above analysis, the embodiments of the present invention aim to provide an unmanned helicopter suspension anti-sway method and system to solve the problems of strong dependence on load mass, limited scope of application and low control accuracy when controlling the existing unmanned aerial vehicle suspension flight system.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] The present invention provides a method for hanging and eliminating sway of an unmanned helicopter, comprising the following steps:

[0007] Respectively obtain the three-axis attitude motion information of the unhooking device adapter plate and the three-axis attitude motion information of the hanging box; wherein the three-axis attitude motion information includes the three-axis attitude angle and the three-axis attitude angular velocity;

[0008] Based on the three-axis posture motion information of the unhooking device adapter plate and the three-axis posture motion information of the hanging box, the swing data of the hanging box relative to the unhooking device adapter plate is calculated;

[0009] Based on the swing data, a swing elimination horizontal acceleration is calculated;

[0010] Based on the sway elimination horizontal acceleration, the sway elimination angle output by the sway elimination controller is calculated, and the sway elimination angle, as well as the current attitude angle and target attitude angle of the unmanned helicopter are input into the attitude controller to control the unmanned helicopter.

[0011] Furthermore, the swing data includes a swing angle and a swing angular acceleration; the swing data of the hanging box relative to the unhooking device adapter plate obtained by calculation includes:

[0012] Based on the three-axis attitude angles of the unhooking device adapter plate and the three-axis attitude angles of the hanging box, a rotation matrix of the hanging box relative to the unhooking device adapter plate is obtained;

[0013] Based on the rotation matrix, the swing angle of the hanging box relative to the unhooking device adapter plate is obtained;

[0014] Based on the three-axis attitude angular velocity of the unhooker adapter plate, the three-axis attitude angular velocity of the hanging box and the rotation matrix of the hanging box relative to the unhooker adapter plate, the swing angular acceleration of the hanging box relative to the unhooker adapter plate is obtained.

[0015] Furthermore, the rotation matrix of the hanging box relative to the unhooking device adapter plate is calculated by the following formula:

[0016]

[0017] Among them, bx represents the attitude angle of the hanging box in the x-axis direction; by represents the attitude angle of the hanging box in the y-axis direction; bz represents the attitude angle of the hanging box in the z-axis direction; ax represents the attitude angle of the unhooking device adapter plate in the x-axis direction; ay represents the attitude angle of the unhooking device adapter plate in the y-axis direction; az represents the attitude angle of the unhooking device adapter plate in the z-axis direction.

[0018] Furthermore, the swing angle of the hanging box relative to the unhooking device adapter plate is calculated by the following formula:

[0019] β x =r 32 / r 33

[0020] β y =-r 31

[0021] Among them, β x Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the x-axis direction; β y Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the y-axis direction; r 31 The third row and first column element of the rotation matrix of the hanging box relative to the unhooking device adapter plate; r 32The third row and second column element of the rotation matrix of the hanging box relative to the unhooking device adapter plate; r 33 Represents the third row and third column element of the rotation matrix of the hanging box relative to the unhooking device adapter plate.

[0022] Furthermore, the swing angular acceleration of the hanging box relative to the unhooking device adapter plate is calculated by the following formula:

[0023]

[0024] in, It represents the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the x-axis direction; Indicates the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the y-axis direction; represents the swing angular acceleration of the hanging box relative to the unhooker adapter plate in the z-axis direction; bwx represents the attitude angular velocity of the hanging box in the x-axis direction; bwy represents the attitude angular velocity of the hanging box in the y-axis direction; bwz represents the attitude angular velocity of the hanging box in the z-axis direction; awx represents the attitude angular velocity of the unhooker adapter plate in the x-axis direction; awy represents the attitude angular velocity of the unhooker adapter plate in the y-axis direction; awz represents the attitude angular velocity of the unhooker adapter plate in the z-axis direction.

[0025] Furthermore, the horizontal acceleration of the anti-sway is calculated using the following formula:

[0026]

[0027]

[0028] Where g is the acceleration of gravity; L is the length of the hanging rope; λ is the time constant of the swing stabilization system; β x Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the x-axis direction; β y Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the y-axis direction; It represents the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the x-axis direction; It represents the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the y-axis direction.

[0029] Furthermore, based on the sway elimination horizontal acceleration, the angle change output by the sway elimination controller is calculated using the following formula:

[0030] Δθ=α h,x / g

[0031]

[0032] Among them, Δθ represents the change in pitch angle; Indicates the change in roll angle.

[0033] Furthermore, the target attitude angle of the unmanned helicopter is calculated by a speed controller based on the current speed of the unmanned helicopter and the target speed of the unmanned helicopter.

[0034] Furthermore, a first attitude sensor and a second attitude sensor are respectively arranged at the unhooking device adapter plate of the unmanned helicopter and the hook of the hanging box at the bottom of the hanging rope to obtain three-axis attitude motion information of the unhooking device adapter plate and the three-axis attitude motion information of the hanging box respectively.

[0035] On the other hand, the present invention provides an unmanned helicopter suspension anti-sway control system, comprising:

[0036] A speed controller, used to calculate the target attitude angle of the unmanned helicopter based on the current speed and target speed of the unmanned helicopter;

[0037] The anti-sway controller is used to calculate the anti-sway angle based on the three-axis attitude motion information of the unhooking device adapter plate and the three-axis attitude motion information of the hanging box obtained by the first attitude sensor and the second attitude sensor arranged at the unhooking device adapter plate of the unmanned helicopter and the hanging box hook at the bottom of the hanging rope;

[0038] The attitude controller is used to control the unmanned helicopter based on the current attitude angle of the unmanned helicopter, the target attitude angle and the anti-sway angle.

[0039] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0040] 1. The anti-sway method designed in the present invention can effectively solve the problem of the swing of the hanging objects during the unmanned transport helicopter's forward flight and the influence of the hanging objects on the stable flight. It is suitable for different load swing angles. When the swing angle fluctuates greatly, feedback control can still be used to ensure that the system is quickly stable.

[0041] 2. The anti-sway method of the present invention avoids introducing force information through acceleration feedback, so it does not need to be based on the known mass of the suspended load. The control effect does not depend on the load mass and is not limited to use under small disturbance models such as the hovering mode of an unmanned helicopter.

[0042] 3. The present invention uses a low-cost, small-mass tilt sensor to complete the anti-sway control, which is suitable for various types of drones and has the advantages of wide application range, low cost, simple integration, and easy transplantation.

[0043] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0045] Figure 1 It is a schematic diagram of the mechanical structure of the hanging and anti-swaying airborne terminal device of the unmanned helicopter in an embodiment of the present invention;

[0046] Figure 2 It is a schematic diagram of the flow of the method for eliminating the sway of the unmanned helicopter suspension in an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the electrical connection relationship of the suspension and sway elimination of an unmanned helicopter in an embodiment of the present invention;

[0048] Figure 4 It is a schematic diagram of the hanging swing principle of an unmanned helicopter in an embodiment of the present invention;

[0049] Figure 5 is a block diagram of an unmanned helicopter control system according to an embodiment of the present invention;

[0050] Figure 6 It is a structural schematic diagram of the unmanned helicopter suspension sway elimination system in an embodiment of the present invention.

[0051] Reference numerals:

[0052] 1-airborne end adapter plate; 2-airborne end hook; 3-sensor A; 4-airborne end rope; 5-unhooking device adapter plate; 6-unhooking device; 7-rope; 8-sensor B. DETAILED DESCRIPTION

[0053] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0054] The suspension sway elimination control method of the present invention is mainly aimed at the problems of the suspended objects being disturbed and swinging during the forward flight of an unmanned transport helicopter and the influence of the suspended objects on the stable flight. The suspension object swing angle information is introduced to control the UAV motion, thereby achieving the purpose of quickly eliminating the swing and connecting in a short time.

[0055] In a specific embodiment of the present invention, the mechanical structure of the hanging and anti-swaying airborne device of the unmanned helicopter is as follows: Figure 1 As shown, the unhooking device adapter plate 5 is connected to the four onboard end hooks 2 through four onboard lifting ropes 4, the four onboard end hooks 2 are connected to the unmanned helicopter body through four onboard end adapter plates 1, and the lifting rope 7 is connected to the unhooking device adapter plate 5 through the unhooking device 6. The anti-sway device of this embodiment can avoid the problem of insufficient body strength caused by excessive cargo mass in the single-point hanging mode, and at the same time reduce the influence of complex vibration modes caused by rigid connection on the control of the unmanned helicopter itself.

[0056] Specifically, this embodiment discloses a method for eliminating the swing of an unmanned helicopter suspension, such as Figure 2 As shown, the steps S1 to S4 are included:

[0057] Step S1, respectively obtaining the three-axis posture motion information of the unhooking device adapter plate and the three-axis posture motion information of the hanging box; wherein the three-axis posture motion information includes the three-axis posture angle and the three-axis posture angular velocity.

[0058] Specifically, in order to simplify the complex movement characteristics of the suspended object caused by the flexible connection mechanism, the suspension sway elimination device of this embodiment uses two attitude sensors to simplify the swing angle between the suspension rope and the machine body to the swing angle between the suspension rope and the adapter plate of the sway elimination device unhooking device.

[0059] Furthermore, a first attitude sensor and a second attitude sensor are respectively arranged at the unhooking device adapter plate of the unmanned helicopter and the hook of the hanging box at the bottom of the hanging rope to obtain three-axis attitude motion information of the unhooking device adapter plate and the three-axis attitude motion information of the hanging box respectively.

[0060] Specifically, Figure 3 As shown in the electrical connection diagram, sensor A is set on the unhooking device adapter plate, and sensor B is set on the cargo box at the bottom of the sling. The two attitude sensors respectively send the measured three-axis attitude angles and three-axis attitude angular velocities of the unhooking device adapter plate and the hanging box to the flight control computer through the WIFI signal receiver. The flight control computer then estimates the angle and angular velocity of the hanging box according to the measured sensor angle difference, and calculates the UAV anti-swing acceleration command according to the estimation result, completes the command tracking in the anti-swing mode, and realizes intelligent anti-swing control.

[0061] Exemplarily, the attitude sensor is a sensor capable of measuring angular velocity and angular acceleration, which may be a gyroscope, an inclinometer, an accelerometer, a magnetometer, a MEMS angular velocity sensor, and the like.

[0062] Step S2: based on the three-axis posture motion information of the unhooking device adapter plate and the three-axis posture motion information of the hanging box, the swing data of the hanging box relative to the unhooking device adapter plate is calculated.

[0063] Specifically, Figure 4 The hanging swing principle shown in the figure applies an acceleration control to the unmanned helicopter. The unhooking device adapter plate generates acceleration following the unmanned helicopter, and the hanging box obtains a reverse relative acceleration. Without considering external interference conditions such as wind resistance, the hanging box performs a simple pendulum motion relative to the unhooking device adapter plate during steady-state flight.

[0064] Furthermore, the swing data includes the swing angle and the swing angular acceleration.

[0065] Specifically, the swing angle can detect the current state of the hanging box, and the swing angular acceleration represents the rate of change of the swing speed, which can predict the future swing angle. The swing data of the hanging box relative to the unhooker adapter plate can monitor the state of the hanging box and control the swing of the hanging box.

[0066] Specifically, the calculation to obtain the swing data of the hanging box relative to the unhooking device adapter plate includes the following steps S201 to S203:

[0067] Step S201: obtaining a rotation matrix of the hanging box relative to the unhooking device adapter plate based on the three-axis attitude angles of the unhooking device adapter plate and the three-axis attitude angles of the hanging box.

[0068] Specifically, since the suspension rope is twisted during flight, it is impossible to ensure that the inclination angles measured by the upper and lower sensors are in the same coordinate system. Therefore, to estimate the suspension rope swing data, it is necessary to first convert the angle measured by sensor B at the cargo box end into the angle in the coordinate system of sensor A at the onboard end of the unmanned helicopter, that is, calculate the projection of the attitude angle of the sensor at the cargo box end in the onboard coordinate system based on the heading difference measured by the upper and lower sensors.

[0069] The formula for the rotation matrix around the x-axis, y-axis and z-axis is as follows:

[0070]

[0071]

[0072]

[0073] Among them, δ x ,δ y ,δ y Represent the attitude angles on the x-axis, y-axis, and z-axis respectively.

[0074] For the unmanned helicopter airborne sensor A, its rotation matrix can be expressed as follows:

[0075] R A =R x (ax)*R y(ay)*R z (az)

[0076] Wherein, ax represents the attitude angle of the unhooker adapter plate in the x-axis direction; ay represents the attitude angle of the unhooker adapter plate in the y-axis direction; az represents the attitude angle of the unhooker adapter plate in the z-axis direction.

[0077] For the sensor B at the hanging object end, its rotation matrix can be expressed as follows:

[0078] R B =R x (bx)*R y (by)*R z (bz)

[0079] Among them, bx represents the attitude angle of the hanging box in the x-axis direction; by represents the attitude angle of the hanging box in the y-axis direction; bz represents the attitude angle of the hanging box in the z-axis direction.

[0080] Since the reference coordinates of sensor A and sensor B in the z-axis direction are the same, the rotation angle of sensor B at the hanging object end relative to sensor A on the unmanned helicopter on the z-axis is -az+bz.

[0081] Furthermore, the rotation matrix of the hanging object end sensor B relative to the unmanned helicopter airborne end sensor A can be expressed as follows:

[0082]

[0083] Step S202: Based on the rotation matrix, obtain the swing angle of the hanging box relative to the unhooking device adapter plate.

[0084] Furthermore, the swing angle of the hanging box relative to the unhooking device adapter plate is calculated by the following formula:

[0085] β x =r 32 / r 33

[0086] β y =-r 31

[0087] Among them, β x Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the x-axis direction; β y Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the y-axis direction; r 31 The third row and first column element of the rotation matrix of the hanging box relative to the unhooking device adapter plate; r 32 The third row and second column element of the rotation matrix of the hanging box relative to the unhooking device adapter plate; r 33Represents the third row and third column element of the rotation matrix of the hanging box relative to the unhooking device adapter plate.

[0088] Specifically, according to the orthogonality of the rotation matrix and the properties of the inverse matrix, the third row of the rotation matrix represents the unit vector pointing to the z-axis after the rotation around the z-axis. 31 It is the element in the third row and first column of the rotation matrix, which represents the projection of the z-axis on the x-axis after rotation. 32 It is the element in the third row and second column of the rotation matrix, which represents the projection of the rotated z-axis on the y-axis. 33 It is the element in the third row and third column of the rotation matrix. It is an element in an orthogonal unit vector and represents the cosine value of the Z-axis direction after rotation.

[0089] It should be noted that the coordinate system is the unmanned helicopter coordinate system, and the X, Y, and Z axes represent the forward flight direction of the unmanned helicopter body, the right direction of the unmanned helicopter body, and the upward direction of the unmanned helicopter, respectively.

[0090] Step S203, obtaining the swing angular acceleration of the hanging box relative to the unhooking device adapter plate based on the three-axis attitude angular velocity of the unhooking device adapter plate, the three-axis attitude angular velocity of the hanging box and the rotation matrix of the hanging box relative to the unhooking device adapter plate.

[0091] Specifically, by calculating the swing angular acceleration of the hanging box relative to the unhooking device adapter plate, the movement trend of the hanging box can be predicted, and the control strategy can be adjusted in time to suppress excessive swing.

[0092] Furthermore, the swing angular acceleration of the hanging box relative to the unhooking device adapter plate is calculated by the following formula:

[0093]

[0094] in, It represents the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the x-axis direction; Indicates the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the y-axis direction; represents the swing angular acceleration of the hanging box relative to the unhooker adapter plate in the z-axis direction; bwx represents the attitude angular velocity of the hanging box in the x-axis direction; bwy represents the attitude angular velocity of the hanging box in the y-axis direction; bwz represents the attitude angular velocity of the hanging box in the z-axis direction; awx represents the attitude angular velocity of the unhooker adapter plate in the x-axis direction; awy represents the attitude angular velocity of the unhooker adapter plate in the y-axis direction; awz represents the attitude angular velocity of the unhooker adapter plate in the z-axis direction.

[0095] Step S3: Calculate and obtain the sway elimination horizontal acceleration based on the sway data.

[0096] Specifically, according to Figure 4 The hanging and swinging principle shown in the figure, the hanging rope of the hanging box swings sideways relative to the vertical direction at angles of β x and β y At this time, the relative speed between the hanging box and the unhooking device adapter plate is as follows:

[0097]

[0098]

[0099] Wherein, L represents the length of the hanging rope; the subscripts x and y represent the projection directions of the swing angle, respectively, wherein x represents the forward flight direction of the unmanned helicopter body; y represents the right direction of the unmanned helicopter body; represents the swing angular velocity of the hanging rope in the x direction; It represents the swing angular velocity of the hanging rope in the x direction.

[0100] The goal of eliminating the swing of the hanging box is to make the swing angle of the hanging rope in each direction β within a certain period of time x and β y and angular velocity and Converges to 0.

[0101] According to Newton's second law and rotational dynamics, the relationship between the swing angular acceleration and the rate of change of the motion speed of the unhooking device adapter plate is obtained as shown in the following formula:

[0102]

[0103]

[0104] in, and They represent the swing angular acceleration of the hanging rope in the x direction and the y direction respectively; and They respectively represent the movement acceleration of the unhooking device adapter plate.

[0105] The swing angle motion is designed as a second-order linear homogeneous differential equation as follows:

[0106]

[0107]

[0108] Where λ is the time constant of the swing stabilization system.

[0109] The second-order linear homogeneous differential equation simulates the behavior of a damped resonator. By controlling the speed of the drone, the swing of the hanging object can be indirectly controlled. λ represents the damping ratio of the system. The purpose of the equation is to ensure that the swing angle β x and βy The system is in a stable state when it decays to zero over time. The damping ratio λ is used to control the speed of the swing decay. If λ is large, the swing will decay quickly; if λ is small, the swing will decay slowly. For example, the time constant λ of this embodiment can be set to 1.

[0110] From the above formula (2) to formula (5), the relative acceleration between the hanging box and the unhooking device adapter plate can be obtained, as shown in the following formula:

[0111]

[0112]

[0113] in, and They represent the velocity change rate of the unhooking device adapter plate in the x direction and the y direction, that is, the acceleration.

[0114] Since the swing of the hanging box causes the direction of the hanging box relative to the unhooking device adapter plate to change, the relative linear acceleration between the hanging box and the unhooking device adapter plate is obtained by formula (7) and formula (8):

[0115]

[0116]

[0117] Among them, α c,x and α c,y They represent the relative linear acceleration components of the hanging box and the unhooking device adapter plate in the x direction and y direction respectively.

[0118] according to Figure 4 The force analysis of the hanging swing principle shown in the figure, the gravity acceleration of the hanging box in the x-direction and the y-direction is shown as follows:

[0119] α g,x =gtanβ x (11)

[0120] α g,y =gtanβ y (12)

[0121] Based on the relative linear acceleration between the hanging box and the unhooking device adapter plate and the gravity acceleration of the hanging box, the following formula is used to obtain the acceleration component (α h,x ,α h,y ):

[0122] α c,x =α g,x -α h,x (13)

[0123] α c,y =α g,y -α h,y (14)

[0124] Among them, α h,x and α h,y They represent the acceleration components in the x and y directions caused by the reaction force of the unmanned helicopter control hanging box.

[0125] Furthermore, according to formula (9) to formula (14), the acceleration that needs to be eliminated is obtained as shown in the following formula:

[0126]

[0127]

[0128] Where g is the acceleration of gravity; L is the length of the hanging rope; λ is the time constant of the swing stabilization system; β x Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the x-axis direction; β y Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the y-axis direction; It represents the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the x-axis direction; It represents the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the y-axis direction.

[0129] Step S4, based on the sway elimination horizontal acceleration, calculate the sway elimination angle output by the sway elimination controller, input the sway elimination angle, as well as the current attitude angle and target attitude angle of the unmanned helicopter into the attitude controller to control the unmanned helicopter.

[0130] Specifically, the block diagram of the unmanned helicopter control system implemented in this embodiment is as follows: Figure 5 As shown, in the unmanned helicopter speed tracking mode, the speed error between the target speed of the unmanned helicopter and the current speed of the unmanned helicopter is solved by the speed controller to obtain the target attitude angle of the unmanned helicopter. The target attitude angle is superimposed on the anti-sway angle output by the anti-sway controller and the attitude angle of the current unmanned helicopter, and the control input value of the unmanned helicopter is calculated by the attitude controller to control the unmanned helicopter to reach the target speed while achieving the purpose of quickly suppressing the swing angle of the hanging box.

[0131] The current attitude angle of the unmanned helicopter is measured by the navigation equipment carried by the unmanned helicopter; the control quantity of the unmanned helicopter output by the attitude controller is the pitch change of the lateral and longitudinal periods, that is, the angle of attack of the rotor blades is adjusted in different phases to achieve the pitch, yaw and roll control of the unmanned helicopter.

[0132] Furthermore, based on the sway elimination horizontal acceleration, the angle change output by the sway elimination controller is calculated using the following formula:

[0133] Δθ=α h,x / g

[0134]

[0135] Among them, Δθ represents the change in pitch angle; Indicates the change in roll angle.

[0136] Specifically, the pitch angle variation is the amount of the unmanned helicopter's pitch angle variation calculated by the anti-sway controller to offset the swing of the hanging object in the vertical plane (such as forward and backward swing) to generate the torque required to suppress the swing of the hanging object.

[0137] The roll angle change is for the unmanned helicopter to offset the swing of the hanging object in the horizontal plane (such as left and right swing). The anti-sway controller will calculate a suitable roll angle change so that the unmanned helicopter can generate the necessary torque by adjusting its roll posture, thereby suppressing or eliminating the swing of the hanging object.

[0138] Specifically, the anti-swing controller is a control system for suppressing or eliminating the swing phenomenon. The anti-swing controller may use a PID controller, an LQR (linear quadratic regulator) controller, a state feedback controller, etc., which is not required in this embodiment.

[0139] The speed controller calculates the angular acceleration or speed change required to control the unmanned helicopter based on the difference between the current speed of the unmanned helicopter and the predetermined target speed, and then obtains the angle required to achieve the target speed; the speed controller can also use a PID controller, an LQR (linear quadratic regulator) controller, a state feedback controller, etc., which is not required in this embodiment.

[0140] Exemplarily, an embodiment of the present invention is applied to a small unmanned helicopter, which is a conventional single-rotor with a tail rotor, with a main rotor diameter of 2.1 meters. The attitude controller uses a conventional PID controller, and the speed controller uses a feedforward controller combined with PI control to achieve speed tracking. The cargo box is mounted by a single-point hanging fixed rope length method, with a rope length of 5 meters. The swing angle stabilization system λ=1 is designed in combination with the response characteristics of the unmanned helicopter, and the anti-swing controller is introduced through a switch quantity. According to the actual flight test results, the method of the embodiment of the present invention is used to perform anti-swing control. When the anti-swing mode is turned off, the helicopter is manually manipulated to swing, and the suspension swing angle is increased to a maximum swing angle of 11.4 degrees. After turning on the anti-swing mode, the swing angle can be stabilized to within 2 degrees within 3 seconds.

[0141] Another embodiment of the present invention discloses an unmanned helicopter suspension anti-sway control system, such as Figure 6 As shown, the system includes:

[0142] The speed controller 601 is used to calculate the target attitude angle of the unmanned helicopter based on the current speed and target speed of the unmanned helicopter;

[0143] The anti-sway controller 602 is used to calculate the anti-sway angle based on the three-axis attitude motion information of the unhooking device adapter plate and the three-axis attitude motion information of the hanging box obtained by the first attitude sensor and the second attitude sensor arranged at the unhooking device adapter plate of the unmanned helicopter and the hanging box hook at the bottom of the hanging rope;

[0144] The attitude controller 603 is used to control the unmanned helicopter based on the current attitude angle of the unmanned helicopter, the target attitude angle and the anti-sway angle.

[0145] The above system embodiment and method embodiment are based on the same principle, and their related parts can be used for reference, and can achieve the same technical effect. The specific implementation process refers to the above embodiment, which will not be repeated here.

[0146] In summary, the unmanned helicopter suspension anti-sway control method and system according to the embodiment of the present invention have the following beneficial effects:

[0147] 1. The anti-sway method designed in the present invention can effectively solve the problem of the swing of the hanging objects during the unmanned transport helicopter's forward flight and the influence of the hanging objects on the stable flight. It is suitable for different load swing angles. When the swing angle fluctuates greatly, feedback control can still be used to ensure that the system is quickly stable.

[0148] 2. The anti-sway method of the present invention avoids introducing force information through acceleration feedback, so it does not need to be based on the known mass of the suspended load. The control effect does not depend on the load mass and is not limited to use under small disturbance models such as the hovering mode of an unmanned helicopter.

[0149] 3. The present invention uses a low-cost, small-mass tilt sensor to complete the anti-sway control, which is suitable for various types of drones and has the advantages of wide application range, low cost, simple integration, and easy transplantation.

[0150] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for eliminating sway in hanging of an unmanned helicopter, characterized in that: The steps include: Respectively obtain the three-axis attitude motion information of the unhooking device adapter plate and the three-axis attitude motion information of the hanging box; wherein the three-axis attitude motion information includes the three-axis attitude angle and the three-axis attitude angular velocity; Based on the three-axis posture motion information of the unhooking device adapter plate and the three-axis posture motion information of the hanging box, the swing data of the hanging box relative to the unhooking device adapter plate is calculated; Based on the swing data, a swing elimination horizontal acceleration is calculated; Based on the sway elimination horizontal acceleration, the sway elimination angle output by the sway elimination controller is calculated, and the sway elimination angle, as well as the current attitude angle and target attitude angle of the unmanned helicopter are input into the attitude controller to control the unmanned helicopter.

2. The method according to claim 1, characterized in that: The swing data includes a swing angle and a swing angular acceleration; the swing data of the hanging box relative to the unhooking device adapter plate obtained by calculation includes: Based on the three-axis attitude angles of the unhooking device adapter plate and the three-axis attitude angles of the hanging box, a rotation matrix of the hanging box relative to the unhooking device adapter plate is obtained; Based on the rotation matrix, the swing angle of the hanging box relative to the unhooking device adapter plate is obtained; Based on the three-axis attitude angular velocity of the unhooker adapter plate, the three-axis attitude angular velocity of the hanging box and the rotation matrix of the hanging box relative to the unhooker adapter plate, the swing angular acceleration of the hanging box relative to the unhooker adapter plate is obtained.

3. The method according to claim 2, characterized in that: The rotation matrix of the hanging box relative to the unhooking device adapter plate is calculated by the following formula: Among them, bx represents the attitude angle of the hanging box in the x-axis direction; by represents the attitude angle of the hanging box in the y-axis direction; bz represents the attitude angle of the hanging box in the z-axis direction; ax represents the attitude angle of the unhooking device adapter plate in the x-axis direction; ay represents the attitude angle of the unhooking device adapter plate in the y-axis direction; az represents the attitude angle of the unhooking device adapter plate in the z-axis direction.

4. The method according to claim 3, characterized in that: The swing angle of the hanging box relative to the unhooking device adapter plate is calculated by the following formula: β x ＝r 32 / r 33 β y ＝-r 31 Among them, β x Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the x-axis direction; β y Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the y-axis direction; r 31 The third row and first column element of the rotation matrix of the hanging box relative to the unhooking device adapter plate; r 32 The third row and second column element of the rotation matrix of the hanging box relative to the unhooking device adapter plate; r 33 Represents the third row and third column element of the rotation matrix of the hanging box relative to the unhooking device adapter plate.

5. The method according to claim 4, characterized in that: The swing angular acceleration of the hanging box relative to the unhooking device adapter plate is calculated by the following formula: in, It represents the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the x-axis direction; Indicates the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the y-axis direction; represents the swing angular acceleration of the hanging box relative to the unhooker adapter plate in the z-axis direction; bwx represents the attitude angular velocity of the hanging box in the x-axis direction; bwy represents the attitude angular velocity of the hanging box in the y-axis direction; bwz represents the attitude angular velocity of the hanging box in the z-axis direction; awx represents the attitude angular velocity of the unhooker adapter plate in the x-axis direction; awy represents the attitude angular velocity of the unhooker adapter plate in the y-axis direction; awz represents the attitude angular velocity of the unhooker adapter plate in the z-axis direction.

6. The method according to claim 1, characterized in that: Use the following formula to calculate the horizontal acceleration of the sway elimination: Where g is the acceleration of gravity; L is the length of the hanging rope; λ is the time constant of the swing stabilization system; β x Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the x-axis direction; β y Indicates the swing angle of the hanging box relative to the unhooking device adapter plate in the y-axis direction; It represents the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the x-axis direction; It represents the swing angular acceleration of the hanging box relative to the unhooking device adapter plate in the y-axis direction.

7. The method according to claim 6, characterized in that: Based on the horizontal acceleration of the sway elimination, the angle change output by the sway elimination controller is calculated using the following formula: Δθ=a h,x / g Among them, Δθ represents the change in pitch angle; Indicates the change in roll angle.

8. The method according to any one of claims 1 to 7, characterized in that: The target attitude angle of the unmanned helicopter is calculated by a speed controller based on the current speed of the unmanned helicopter and the target speed of the unmanned helicopter.

9. The method according to claim 1, characterized in that: A first attitude sensor and a second attitude sensor are respectively arranged at the unhooker adapter plate of the unmanned helicopter and the hook of the hanging box at the bottom of the hanging rope to obtain three-axis attitude motion information of the unhooker adapter plate and the three-axis attitude motion information of the hanging box.

10. An unmanned helicopter suspension anti-sway control system, characterized in that: include: A speed controller, used to calculate the target attitude angle of the unmanned helicopter based on the current speed and target speed of the unmanned helicopter; The anti-sway controller is used to calculate the anti-sway angle based on the three-axis attitude motion information of the unhooking device adapter plate and the three-axis attitude motion information of the hanging box obtained by the first attitude sensor and the second attitude sensor arranged at the unhooking device adapter plate of the unmanned helicopter and the hanging box hook at the bottom of the hanging rope; The attitude controller is used to control the unmanned helicopter based on the current attitude angle of the unmanned helicopter, the target attitude angle and the anti-sway angle.

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