A relative position-based method of controlling the motion of a suspended object

Abstract

This invention relates to the field of unmanned helicopter sling load control technology, and discloses a method for controlling the motion of a suspended object based on relative position. First, the real-time motion state of the suspended object is calculated based on the real-time motion states of the unmanned helicopter and the suspended object. Then, the motion control target of the suspended object is compared with its actual motion state to obtain the deviation of the suspended object's motion control quantity. Next, based on the real-time motion state of the unmanned helicopter and the relative motion state correction, a target motion state command for the unmanned helicopter is output to control its real-time motion state, thereby achieving motion control of the suspended object. Here, the motion state is either position or velocity. This invention solves the problem in existing technologies where the lack of effective control over the motion of the suspended object prevents the sling transport system from being applied to precision operation scenarios with high requirements for the motion of the suspended object.

Description

Technical Field

[0001] This invention relates to the field of unmanned helicopter sling control technology, specifically a method for controlling the motion of slings based on relative position. Background Technology

[0002] Unmanned helicopters, as ideal operational platforms, possess advantages such as high mobility, minimal restrictions on takeoff and landing sites, and short maintenance and preparation cycles. They can quickly and efficiently carry out high-intensity, high-frequency missions, and are increasingly widely used in both military and civilian fields. As a convenient means of air transport, logistics transportation has become an important application area for unmanned helicopters.

[0003] Compared to fixed-wing unmanned helicopters that use fixed transport devices installed inside and outside the cabin, unmanned helicopters typically use tethered sling structures for logistics transportation. This method avoids the matching problem between the shape of the helicopter and the load, and does not need to consider the limitations of the loading volume. At the same time, it can maintain a certain distance between the helicopter and the load, ensuring that the helicopter's attitude and maneuverability are not affected, and it is more suitable for environments that may pose a safety threat to the aircraft, such as disaster areas and minefields.

[0004] Sling transport systems exhibit nonlinear, strongly coupled, time-varying, and underactuated characteristics, typically requiring sway mitigation measures to ensure the safety of aerial equipment, ground facilities, and personnel. Sling mitigation measures rely on a sling mitigation controller to correct and compensate for the helicopter's reference trajectory, reducing system sway energy to suppress sling sway. However, the lack of effective control over the movement of the suspended load prevents sling transport systems from being applied to precision-controlled operations requiring precise control over the movement of the suspended load, such as disaster search and rescue and minefield scanning. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a method for controlling the motion of suspended objects based on relative position, which solves the problem that the lack of effective control over the motion of suspended objects in existing technologies prevents the application of suspended transport systems to precision operation scenarios with high requirements for the motion of suspended objects.

[0006] The technical solution adopted by the present invention to solve the above problems is:

[0007] A method for controlling the motion of a suspended object based on relative position is proposed. First, the real-time motion state of the suspended object is solved based on the real-time motion state of the unmanned helicopter and the suspended object. Then, the motion control target of the suspended object is compared with the actual motion state to obtain the deviation of the motion control quantity of the suspended object. Based on the real-time motion state of the unmanned helicopter and the relative motion state correction, the target motion state command of the unmanned helicopter is output to control the real-time motion state of the unmanned helicopter, thereby realizing the motion control of the suspended object. Here, the motion state is either position or velocity.

[0008] As a preferred technical solution, if the motion control target is the position of the suspended object, the following steps are included:

[0009] S1, realizes the perception of the relative motion state between the unmanned helicopter and the suspended object: based on the real-time position of the unmanned helicopter. , And the real-time relative position of the unmanned helicopter and the suspended object. Determine the real-time position of the suspended object. , ;in, For time, This represents the longitudinal component of the real-time position of the unmanned helicopter. This represents the lateral component of the real-time position of the unmanned helicopter. The angle of inclination of the suspended object in a non-inertial frame of reference. The longitudinal component is denoted as , The horizontal component is denoted as , The longitudinal component represents the real-time position of the suspended object. The lateral component represents the real-time position of the suspended object;

[0010] S2, compare the target motion control of the suspended object with its actual motion state to obtain the deviation of the motion control quantity of the suspended object. ;

[0011] in, For deviations in the motion control of suspended objects;

[0012] S3, due to the deviation in the motion control of the suspended object. The relative motion state correction was calculated. Combining the real-time relative positions of the unmanned helicopter and the suspended object Real-time location of unmanned helicopters , Received the target location command from the unmanned helicopter , ;

[0013] in, Correction for relative motion state. The longitudinal component of the target position command for the unmanned helicopter. The lateral component of the target position command for the unmanned helicopter.

[0014] As a preferred technical solution, if the motion control target is the position of the suspended object, in step S1, the relationship between the actual tilt angle of the suspended object in the non-inertial reference frame and the tilt angle measured by the tilt sensor is as follows:

[0015] ;

[0016] in, This represents the true tilt angle of the suspended object in a non-inertial reference frame. The tilt angle of the suspended object is measured in a non-inertial reference frame. The actual swing acceleration of the suspended object. The oscillation acceleration measured at the installation position of the tilt sensor. To accelerate the suspension system, It is the acceleration due to gravity. This refers to the distance between the hanging hinge and the suspended object. This refers to the distance between the hanging hinge and the tilt sensor.

[0017] As a preferred technical solution, if the motion control target is the position of the suspended object, the correction of the relative position in step S1 is as follows:

[0018] ;

[0019] ;

[0020] in, for The longitudinal component, for The horizontal component, This is the distance between the longitudinal hinge and the suspended object. This is the distance between the horizontal hinge and the suspended object. This is the distance between the longitudinal hinge and the tilt sensor. This is the distance between the lateral hinge and the tilt sensor. for The longitudinal component, for The horizontal component, for The longitudinal component, for The horizontal component.

[0021] As a preferred technical solution, if the motion control target is the position of the suspended object, in step S1, , The calculation formula is:

[0022] ;

[0023] ;

[0024] in, The longitudinal component represents the position of the suspended object. This represents the lateral component of the hanging object's position.

[0025] As a preferred technical solution, if the motion control target is the position of the suspended object, in step S2, The calculation formula is:

[0026] ;

[0027] ;

[0028] in, The deviation between the longitudinal position of the suspended target and its actual longitudinal position. The longitudinal position of the suspended object. The deviation between the lateral position of the suspended target and its actual lateral position. This indicates the lateral position of the suspended object.

[0029] As a preferred technical solution, if the motion control target is the position of the suspended object, the calculation formula for the unmanned helicopter position control command in step S3 is:

[0030] ;

[0031] in, For the longitudinal position control correction of the suspended object, Correction amount for controlling the lateral position of the suspended object. This represents the longitudinal component of the real-time position of the unmanned helicopter. The lateral component represents the real-time position of the unmanned helicopter.

[0032] As a preferred technical solution, if the motion control target is the position of the suspended object, the calculation formula for the position control correction of the suspended object is:

[0033] ;

[0034] in, Correction for relative position The longitudinal component, To control the deviation in the longitudinal position of the suspended object, for The proportional adjustment parameter, for Integral adjustment parameters, for The differential adjustment parameter, Correction for relative position The horizontal component, To control the lateral position deviation of the suspended object, for The proportional adjustment parameter, for Integral adjustment parameters, for The differential adjustment parameter.

[0035] As a preferred technical solution, if the motion control target is the speed of the suspended object, the correction for the swing angular velocity of the suspended object is as follows:

[0036] ;

[0037] ;

[0038] in, The longitudinal component of the true angular velocity of the suspended object. For the lateral component of the true angular velocity of the suspended object, To measure the longitudinal component of the angular velocity of a suspended object. To measure the lateral component of the angular velocity of a suspended object. for Partial derivative with respect to time, for Partial derivative with respect to time.

[0039] As a preferred technical solution, if the motion control target is the velocity of the suspended object, the longitudinal and lateral components of the velocity of the suspended object's center of gravity relative to the origin of the inertial coordinate system are respectively:

[0040] ;

[0041] ;

[0042] in, The longitudinal velocity component of the suspended mass center relative to the origin of the inertial coordinate system. Let be the longitudinal velocity component of the unmanned helicopter's center of mass relative to the origin of the inertial coordinate system. The true angular velocity of the suspended object The longitudinal component, The transverse velocity component of the suspended mass center relative to the origin of the inertial coordinate system. Let be the lateral velocity component of the unmanned helicopter's center of mass relative to the origin of the inertial coordinate system. The true angular velocity of the suspended object The horizontal component.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] This invention proposes a motion control method and system logic for slinging objects from an unmanned helicopter. Based on the accurate perception of the relative positional relationship between the helicopter and the sling, a closed-loop control model is established with the relative position of the UAV and the sling as the control target. By controlling the target position of the UAV, the motion of the sling is precisely controlled. By applying this control method and system control logic, precise control of the motion of the sling can be achieved, which helps to apply the UAV sling system to precision work scenarios with high requirements for the motion of the sling. Attached Figure Description

[0045] Figure 1 Force analysis diagram of the suspended object and sensor;

[0046] Figure 2 A schematic diagram showing the installation positions of the suspended objects and sensors;

[0047] Figure 3 A schematic diagram illustrating the deviation between the tilt angle measured by the sensor and the actual tilt angle of the suspended object.

[0048] Figure 4 This is a schematic diagram showing the arrangement of longitudinal and transverse hinges;

[0049] Figure 5 A simplified schematic diagram of the longitudinal and lateral motion of an unmanned helicopter sling system;

[0050] Figure 6 This is a schematic diagram of the force analysis of the suspended object;

[0051] Figure 7 This is one of the structural block diagrams of a closed-loop control system for the motion of suspended objects.

[0052] Figure 8 This is the second block diagram of the closed-loop control system for the motion of suspended objects. Detailed Implementation

[0053] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0054] Example 1

[0055] like Figures 1 to 8 As shown, this invention proposes a motion control method and system logic for slinging objects from an unmanned helicopter. Based on the precise perception of the relative positional relationship between the unmanned helicopter and the sling, a closed-loop control model is established with the relative position of the unmanned helicopter and the sling as the control target. By controlling the target position of the unmanned helicopter, precise motion control of the sling is achieved. Applying this control method and system control logic enables precise control of the sling's motion, facilitating the application of unmanned helicopter slinging systems in sophisticated work scenarios with high requirements for the motion of slings.

[0056] To accurately sense the sway position of a suspended object, a tilt sensor can be installed in the suspension system. The tilt sensor, using a built-in gyroscope and accelerometer, measures static gravitational acceleration and converts it into a change in tilt angle, thus measuring the tilt and pitch angles relative to the horizontal plane. However, this measurement method is limited to static or slowly changing dynamic environments and is unsuitable for rapidly changing environments. This invention provides a correction method that overcomes this problem, enabling the measurement of the tilt sensor to obtain the true sway position of the suspended object in rapidly changing environments.

[0057] Let the hanging point be Hanging point Fixed connection to the drone. Cable length is... The sensor installation location is far from the hanging point. for The sensor's sensitive shaft follows the swing of the sling. For sensor overload acceleration, The overload acceleration of the suspended object; For the sensor's oscillation acceleration, Let be the acceleration of the suspended object's swing. The motion analysis of the entire suspension system is established within the non-inertial coordinate system of the UAV, and the entire system exhibits motion acceleration. .

[0058] The weight of the suspended object is much greater than the weight of the sling, and the sling is taut. Therefore, the swaying displacement of each point on the sling relative to the equilibrium position is linearly distributed along the length of the sling. The swaying velocity and acceleration of each point on the sling relative to the equilibrium position are also linearly distributed along the length of the sling. That is:

[0059] (1)

[0060] Based on the force analysis, we can obtain:

[0061] (2)

[0062] A tilt sensor is actually an acceleration sensor that uses the principle of inertia. Its essence in measuring tilt angle is to convert the component of overload acceleration on the sensor's sensitive axis into the angle between the overload acceleration and the sensor's sensitive axis. When the sensor is installed at a non-suspended position ( The sensor's sensitive axis direction is opposite to the overload acceleration direction. The included angle is not the tilt angle of the suspended object. It only applies when the sensor is installed at the suspension point. The sensor's sensitive axis direction changes with the oscillation, and the sensor's sensitive axis is related to the overload acceleration direction ( The angle between the two sides is the tilt angle of the suspended object.

[0063] Considering that the measurement of tilt angle may be inaccurate when the sensor is installed at a non-suspending point, this invention proposes a sensor tilt angle correction method. After correction, the tilt angle sensor installed at any position in the suspension system can obtain an accurate tilt angle measurement value.

[0064] Install the tilt sensor on the hook (or bracket), as shown in the installation diagram. Figure 2 As shown. Oscillation acceleration, gravitational acceleration, overload acceleration, system acceleration, and sensor-measured tilt angle. The actual angle of inclination with the suspended object The relationship between them is as follows Figure 3 As shown.

[0065] Based on the small angle assumption and the linear relationship of the swing acceleration (see equation (1)), the relationship between the true tilt angle of the suspended object and the tilt angle measured by the sensor in the non-inertial reference frame can be obtained as follows:

[0066] (3)

[0067] In a practical suspension system, the swing of the suspended object is a composite motion of the lateral and longitudinal directions. There is a certain distance between the lateral and longitudinal hinges, and the swing length of the suspended object differs in the longitudinal and lateral directions. The components of the system acceleration in the longitudinal and lateral directions are different, so it is necessary to determine the tilt angle correction values ​​for the longitudinal and lateral swings respectively according to the above tilt angle correction formula, as shown in equation (3).

[0068] by Figure 4 Taking the unidirectional hinge arrangement as an example, the pendulum lengths of the sensor in the longitudinal and lateral directions are respectively... and The pendulum lengths of the suspended object in the longitudinal and lateral swings are respectively and The system acceleration in the longitudinal and lateral directions is and The correction for the lateral tilt angle measurement according to equation (3) is as follows:

[0069] (4)

[0070] (5)

[0071] Since the angular velocity is obtained by differentiating the angle with respect to time, and the differential operator is linear, the linear correction for the angle also applies to the angular velocity:

[0072] (6)

[0073] (7)

[0074] Establish a simplified model of the longitudinal and lateral motion of the unmanned helicopter sling system, such as Figure 5As shown. The inertial coordinate system is... ,origin A designated point on the ground within the longitudinal plane of the unmanned helicopter's flight. The axis is the intersection of the flight longitudinal plane and the ground, and is positive along the direction of the helicopter's movement. shaft and The axis is vertical, with left as positive. The pendulum lengths of the suspended object in the longitudinal and lateral swings are respectively... and The swing angles of the suspended object in the longitudinal and lateral directions are: , .

[0075] Let the position vector of the unmanned helicopter's center of mass relative to the Earth's axis in the horizontal plane of motion be... Then the position vector of the suspended mass center relative to the Earth's axis in the horizontal plane of motion is... The longitudinal and lateral positional components can be determined based on the pendulum length and swing angle:

[0076] (8)

[0077] (9)

[0078] Differentiating equations (8) and (9) with respect to time, we obtain the longitudinal and transverse velocity components of the suspended mass center relative to the origin of the inertial coordinate system as follows:

[0079] (10)

[0080] (11)

[0081] Force analysis of the suspended object easily yields conclusions (such as...) Figure 6 As shown), the acceleration of the suspended object is related to the relative position of the UAV and the suspended object (i.e., the swing angle). , The positive correlation is shown in equation (12) under the small angle assumption. Therefore, the movement of the suspended object can be controlled by controlling the relative position of the suspended object and the UAV.

[0082] (12)

[0083] Based on the feedback control principle and the dynamic model of the suspended system, the closed-loop control equation for the motion of the suspended object based on the relative positional relationship between the UAV and the suspended object is established as shown in equation (13). The block diagram of the closed-loop control system is shown in the figure. Figure 7 As shown.

[0084] (13)

[0085] in , To determine the real-time motion parameters of the suspended object , The relative position correction of the feedback solution is shown in formula (14).

[0086] (14)

[0087] In the formula , This refers to the deviation in the longitudinal and lateral motion control of the suspended object. Its value is the difference between the target motion control value and the actual motion state of the suspended object. The motion control deviation can be adapted to different control examples. (Controller parameters...) , , The appropriate option can be selected based on system characteristics and control objectives.

[0088] The closed-loop control model uses the real-time position signal of the UAV. , As input, the drone target location command , For output. Based on the real-time relative position of the drone and the suspended object. , Solve for the real-time motion state of the suspended object. , By comparing the target motion control parameters with the actual motion state of the suspended object, the deviation of the motion control parameters is obtained. , The relative position correction is calculated by the automatic controller. , Combining the relative position status fed back by the tilt sensor, the target position command of the UAV is output after correction. , The system uses relative position correction as control feedback to ensure precise and reliable system control.

[0089] The motion control system for the suspended object can be built by using tilt sensors and nonlinear controllers. According to the closed-loop control equation (13), the control system can control the relative position of the UAV and the suspended object by controlling the target position of the UAV and combining it with real-time relative position feedback, thereby realizing the motion control of the suspended object.

[0090] Furthermore, if the motion state is velocity, the block diagram of the closed-loop control system for the suspended object's motion is shown below. Figure 8 The principle is similar to that when the motion state is a position.

[0091] The present invention has the following key technical points:

[0092] 1. The installation position of the tilt sensor in the suspension system;

[0093] 2. Tilting correction methods for tilt sensors at different installation positions in a non-inertial reference frame;

[0094] 3. A closed-loop control system and method for the motion of a suspended object, with the real-time position of the UAV as input, the motion of the suspended object as the control target, the relative position correction between the UAV and the suspended object as feedback, and the target position of the UAV as the output.

[0095] Example 2

[0096] like Figures 1 to 7 As shown, as a further optimization of Embodiment 1, this embodiment also includes the following technical features based on Embodiment 1:

[0097] Control of suspended object position:

[0098] 1. Install tilt sensors in the suspension system;

[0099] 2. Apply the angular velocity correction formulas (6) and (7) to the raw longitudinal and transverse angular velocity data measured by the tilt sensor;

[0100] 3. Based on the overall parameters of the suspension system, establish the dynamic model of the suspension system (8)-(11);

[0101] 4. Using a nonlinear controller as the core and data from airborne sensors and tilt sensors as feedback, a system is established... Figure 7 The motion control system shown;

[0102] 5. According to equations (13) and (14), when the longitudinal position of the suspended object is... Horizontal position To control the target (motor control deviation) The components in the vertical and horizontal directions are , By controlling the target position of the drone, the relative position of the suspended object and the drone is corrected, thereby achieving precise control over the hovering position of the suspended object.

[0103] Example 3

[0104] like Figures 1 to 6 , Figure 8 As shown, as a further optimization of Embodiment 1, this embodiment also includes the following technical features based on Embodiment 1:

[0105] Trajectory control of suspended objects:

[0106] 1. Install tilt sensors in the suspension system;

[0107] 2. Apply the tilt correction formulas (4) and (5) to the original longitudinal and lateral tilt angle data measured by the tilt sensor;

[0108] 3. Based on the overall parameters of the suspension system, establish the dynamic model of the suspension system (8)-(11);

[0109] 4. Using a nonlinear controller as the core and data from airborne sensors and tilt sensors as feedback, a system is established... Figure 7 The motion control system shown;

[0110] 5. According to equations (13) and (14), when the longitudinal velocity of the suspended object is... Horizontal position To control the target (motor control deviation) The components in the vertical and horizontal directions are , By controlling the target position of the drone, the relative position of the suspended object and the drone is corrected, thereby achieving precise control of the movement trajectory of the suspended object.

[0111] As described above, the present invention can be implemented well.

[0112] All features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A relative position-based method of controlling the motion of a suspended object, characterized by, First, according to the real-time motion state of the unmanned helicopter and the hanging object, the real-time motion state of the hanging object is solved; then, the motion control target of the hanging object is compared with the actual motion state to obtain the motion control amount deviation of the hanging object; and then, based on the real-time motion state of the unmanned helicopter and the relative motion state correction, the target motion state instruction of the unmanned helicopter is output to control the real-time motion state of the unmanned helicopter, so as to realize the motion control of the hanging object; wherein the motion state is position or speed; If the motion control target is the position of the hanging object, the following steps are included: S1, realizing the perception of the relative motion state relationship between the unmanned helicopter and the suspended object: according to the real-time position of the unmanned helicopter , , and the real-time relative position of the unmanned helicopter and the suspended object , the real-time position of the suspended object is solved , ; wherein, is the time, is the longitudinal component of the real-time position of the unmanned helicopter, is the lateral component of the real-time position of the unmanned helicopter, is the inclination angle of the suspended object in the non-inertial reference system, the longitudinal component of , the lateral component of , is the longitudinal component of the real-time position of the suspended object, is the lateral component of the real-time position of the suspended object; S2, compare the motion control target of the hanging object with the actual motion state to obtain a hanging object motion control quantity deviation ; wherein is the deviation of the motion control variable for the suspended object S3, deviation of the suspension movement control amount Calculate the relative motion state correction , combined with the real-time relative position of the unmanned helicopter and the suspension And the real-time position of the unmanned helicopter , Get the target position command of the unmanned helicopter , ; wherein, is a relative motion state correction, is a longitudinal component of a target position command for the unmanned helicopter, is a lateral component of a target position command for the unmanned helicopter; If the motion control target is the position of the hanging object, in step S1, the relationship between the real inclination of the hanging object in the non-inertial reference system and the inclination measured by the inclination sensor is: ； wherein is the true inclination of the suspended object in the non-inertial reference frame, is the measured inclination of the suspended object in the non-inertial reference frame, is the true pendulum acceleration of the suspended object, is the pendulum acceleration measured at the inclination sensor mounting position, is the acceleration of the suspension system, is the acceleration of gravity, is the distance between the suspension hinge and the suspended object, is the distance between the suspension hinge and the inclination sensor; If the motion control target is the position of the hanging object, in step S1, the correction of the relative position is as follows: ； ； wherein is the longitudinal component of is the transverse component of is the distance between the longitudinal hinge and the pendant, is the distance between the transverse hinge and the pendant, is the distance between the longitudinal hinge and the tilt sensor, is the distance between the transverse hinge and the tilt sensor, is the longitudinal component of is the transverse component of is the longitudinal component of is the transverse component of ​​​​​​ 2. A relative position-based control method for the movement of a suspended object according to claim 1, characterized in that, If the motion control target is the position of the suspended object, in step S1... , The calculation formula is: ； ； wherein is the longitudinal component of the position of the suspended object, is the transverse component of the position of the suspended object.

3. A relative position based control method for the movement of a suspended object as claimed in claim 1, wherein, If the motion control target is the position of the suspended object, in step S2, The calculation formula is: ； ； wherein is a deviation of the target longitudinal position of the suspended object from the actual longitudinal position, is a target longitudinal position of the suspended object, is a deviation of the target lateral position of the suspended object from the actual lateral position, is a target lateral position of the suspended object.

4. A relative position-based control method for the movement of a suspended object according to claim 1, characterized in that, If the motion control target is the position of the hanging object, in step S3, the calculation formula of the position control instruction of the unmanned helicopter is: ； wherein, is a longitudinal position control correction amount for the suspended object, is a lateral position control correction amount for the suspended object, is a longitudinal component of the real-time position of the unmanned helicopter, is a lateral component of the real-time position of the unmanned helicopter.

5. A relative position based control method for the movement of a suspended object according to claim 4, wherein, If the motion control target is the position of the hanging object, the calculation formula of the position control correction amount of the hanging object is: ； in, Correction for relative position The longitudinal component, To control the deviation in the longitudinal position of the suspended object, for The proportional adjustment parameter, for Integral adjustment parameters, for The differential adjustment parameter, Correction for relative position The horizontal component, To control the lateral position deviation of the suspended object, for The proportional adjustment parameter, for Integral adjustment parameters, for The differential adjustment parameter.

6. A relative position-based control method for the movement of a suspended object according to claim 2, characterized in that, If the motion control target is the speed of the hanging object, the correction of the swing angular velocity of the hanging object is as follows: ； ； wherein is the longitudinal component of the real angular velocity of the suspended object, is the transversal component of the real angular velocity of the suspended object, is the longitudinal component of the measured angular velocity of the suspended object, is the transversal component of the measured angular velocity of the suspended object, is the longitudinal component of the real angular velocity of the suspended object, is the transversal component of the real angular velocity of the suspended object, is the longitudinal component of the real angular velocity of the suspended object, is the transversal component of the real angular velocity of the suspended object.

7. A relative position based control method for the movement of a suspended object as claimed in claim 2, wherein, If the motion control target is the speed of the hanging object, the longitudinal component and the transverse component of the speed of the center of mass of the hanging object relative to the origin of the inertial coordinate system are respectively: ； ； wherein is the longitudinal velocity component of the sling mass center relative to the origin of the inertial coordinate system, is the longitudinal velocity component of the unmanned helicopter center of mass relative to the origin of the inertial coordinate system, is the longitudinal component of the real angular velocity of the sling , is the lateral velocity component of the sling mass center relative to the origin of the inertial coordinate system, is the lateral velocity component of the unmanned helicopter center of mass relative to the origin of the inertial coordinate system, is the lateral component of the real angular velocity of the sling .

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