A secondary swing anti-swing control method for a hoisting unmanned aerial vehicle

Abstract

The application provides a hoisting unmanned aerial vehicle two-stage swing anti-swing control method, the hoisting unmanned aerial vehicle two-stage swing anti-swing control method is simulated and verified, and the control performance is analyzed. Further applied to the variable rope length two-stage swing hoisting unmanned aerial vehicle system, better replace the experience operation of technical personnel, continuously reduce the error caused by human factors, solve the shortage that the manual control method cannot cope with harsh environment, and the two-stage swing problem generated in the flight process of the unmanned aerial vehicle, improve the safety and reliability of transportation, realize the accurate positioning and swing angle anti-swing during the unmanned aerial vehicle transportation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of crane unmanned aerial vehicle control, and particularly relates to a crane unmanned aerial vehicle two-stage swing anti-swing control method. BACKGROUND

[0002] With the development and application of unmanned aerial vehicles, due to the advantages of flexibility, high transportation efficiency and low cost, unmanned aerial vehicles begin to be widely used in cargo transportation. Unmanned aerial vehicles belong to under-actuated systems, and the under-actuated characteristics are more obvious after adding a hanging load. In actual flight, due to factors such as distance, it is difficult for humans to effectively prevent the hanging load from swinging, which has a great impact on the safety and reliability of unmanned aerial vehicle transportation, and therefore the swing elimination problem of the crane unmanned aerial vehicle becomes an important research direction.

[0003] For the swing elimination problem of the crane unmanned aerial vehicle, many scholars at home and abroad have carried out a lot of research and proposed different control methods, which can be mainly divided into open-loop control and closed-loop control. Most of the methods are based on open-loop control design, such as input shaping and trajectory planning. Huo Xi et al. combined command shaping with double closed-loop control, proposed an improved command shaping method, and verified the stability of the control structure.

[0004] Closed-loop control generally needs to collect data, and compare the collected data with target parameters to adjust the control input. For example, Wang Shizhang et al. proposed a nonlinear control method based on energy coupling, which still has strong robustness even under the influence of unknown wind resistance parameters. The crane unmanned aerial vehicle has similar characteristics with the bridge crane and other hoisting systems. In actual transportation process, the two-stage swing problem caused by the hook cannot be ignored. Liang X. et al. constructed a new energy function for the two-stage swing problem of the crane unmanned aerial vehicle, and proposed a new nonlinear swing elimination controller. Sun Ning et al. proposed an anti-swing control method based on online trajectory planning, which effectively solves the two-stage swing problem of the bridge crane. Shi Haitao et al. analyzed the coupling relationship between the crane and the two-stage swing angle, and designed an anti-swing control strategy for the two-stage swing problem based on energy coupling, and then verified through experiments that the method has excellent robustness. SUMMARY

[0005] SUMMARY

[0006] The purpose of the present application is to provide a crane unmanned aerial vehicle two-stage swing anti-swing control method, which realizes accurate positioning and swing angle anti-swing during unmanned aerial vehicle transportation.

[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: a crane unmanned aerial vehicle two-stage swing anti-swing control method, comprising the following steps:

[0008] Step 1, build the hardware structure of the unmanned aerial vehicle hoisting system with the variable rope length two-stage pendulum swing effect;

[0009] Step 2, based on the dynamic model of the unmanned aerial vehicle hoisting system, construct the variable rope length two-stage pendulum hoisting unmanned aerial vehicle dynamics equation; Step 3, select a smooth expected positioning trajectory to ensure the smooth operation of the unmanned aerial vehicle;

[0010] Step 4, according to the dynamic model of the unmanned aerial vehicle hoisting system, design a pendulum elimination controller;

[0011] Step 5, combine the unmanned aerial vehicle position information, pendulum angle information and the pendulum elimination controller to obtain an input signal, and under the driving of the input signal, complete the dual goals of unmanned aerial vehicle positioning, load and hook pendulum elimination.

[0012] Preferably, the variable rope length two-stage pendulum hoisting unmanned aerial vehicle dynamics equation in step 2 is:

[0013]

[0014] In the formula, , and are the masses of the unmanned aerial vehicle, the hook and the load, and represent the lengths of the hoisting ropes, and represent the swing angles of the hook and the load, is the acceleration of gravity, is the resultant force applied to the unmanned aerial vehicle, is the direction driving force on

[0015] Preferably, the smooth expected positioning trajectory in step 3 is:

[0016]

[0017] In the formula, , is the positioning part trajectory, , is the specified position to which it must converge, and ε is the initial acceleration adjustment parameter, , , , is the gain.

[0018] Preferably, after selecting a smooth expected positioning trajectory in step 3, in order to improve the anti-interference ability of the system, a system generalized load signal is constructed, which contains the unmanned aerial vehicle displacement and swing angle signals:

[0019]

[0020]

[0021] wherein ∈ R+, , , is a positive gain.

[0022] Preferably, the dynamics equation of the variable rope length secondary pendulum crane unmanned aerial vehicle is rewritten in matrix form ;

[0023] wherein , , , , are the inertia matrix, the centripetal force matrix, the gravity vector, the driving vector, and the disturbance vector of the system, respectively.

[0024] Preferably, the anti-swing control law of the anti-swing controller in step 4 is:

[0025]

[0026] wherein , , , , , is a gain.

[0027] Preferably, the anti-swing control law can ensure that the unmanned aerial vehicle reaches the specified position ; the length of the hoisting rope reaches the specified length ; the swing angle of the hook and the load can be effectively suppressed, and the control law meets the system stability requirement, that is, the system should satisfy:

[0028]

[0029] wherein, is the target position in the x direction, is the target position in the z direction, is the target length of the hoisting rope.

[0030] Preferably, the hardware structure of the unmanned aerial vehicle hoisting system in step 1 includes the unmanned aerial vehicle body, the hook and the load, and the hoisting rope between the unmanned aerial vehicle and the hook, and the hoisting rope between the hook and the load.

[0031] Advantages:

[0032] The application simulates and verifies the secondary swing prevention control method of the hoisting unmanned aerial vehicle, and analyzes the control performance. Further application to the variable rope length secondary swing hoisting unmanned aerial vehicle system can better replace the experience operation of technical personnel, continuously reduce the error caused by human factors, solve the deficiency that the artificial control method cannot cope with harsh environment, and solve the secondary swing problem in the flight process of the unmanned aerial vehicle, improve the safety and reliability of transportation, realize accurate positioning and swing angle prevention of the unmanned aerial vehicle during transportation.

[0033] The application is based on the dynamic model of the unmanned aerial vehicle hoisting system, and selects a smooth expected trajectory to ensure the stable operation of the unmanned aerial vehicle. Since the positioning trajectory does not have swing elimination capability, the energy coupling relationship among the unmanned aerial vehicle, the hook and the load is utilized to construct a swing elimination controller of the hoisting system, so that the unmanned aerial vehicle hoisting transportation system can effectively eliminate residual swing angle, realize accurate positioning of the unmanned aerial vehicle, and has strong robustness and stability when subjected to external interference; in addition, the variable rope length characteristic greatly improves the transportation efficiency of the unmanned aerial vehicle, so that the unmanned aerial vehicle hoisting system has the advantages of accurate positioning and swing angle prevention

[0034] . BRIEF DESCRIPTION OF DRAWINGS

[0035] BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a variable rope length secondary swing unmanned aerial vehicle hoisting model schematic diagram of the application.

[0037] Figure 2 It is a hoisting unmanned aerial vehicle x direction position change curve diagram of the application.

[0038] Figure 3 It is a hoisting unmanned aerial vehicle z direction position change curve diagram of the application.

[0039] Figure 4 It is a hoisting unmanned aerial vehicle rope length change curve diagram of the application.

[0040] Figure 5 It is a hoisting unmanned aerial vehicle hook swing angle change curve diagram of the application.

[0041] Figure 6 It is a hoisting unmanned aerial vehicle load swing angle change curve diagram of the application.

[0042] Figure 7 It is a hoisting unmanned aerial vehicle x direction position change curve diagram when subjected to external interference of the application.

[0043] Figure 8 It is a hoisting unmanned aerial vehicle z direction position change curve diagram when subjected to external interference of the application.

[0044] Figure 9 The present invention provides a method for hoisting a drone when subjected to external interference. Rope length variation curve.

[0045] Figure 10 The present invention relates to the swing angle of the hook for hoisting a drone under external interference. Change curve graph.

[0046] Figure 11 The present invention relates to the swing angle of the load of a hoisting drone under external interference. Change curve graph. Detailed Implementation

[0047] DETAILED DESCRIPTION

[0048] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0049] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0050] It should also be noted that, unless otherwise stated, "multiple" means two or more; the terms "upper," "lower," "left," "right," "front end," "rear end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.

[0051] It should be noted that any parts not described in detail in this application are prior art.

[0052] Example 1:

[0053] like Figure 1 As shown, a method for controlling the anti-swing of a two-stage swing of a hoisting drone includes the following steps: Step 1, constructing the hardware structure of a drone hoisting system with a variable rope length two-stage swing effect;

[0054] Step 2: Based on the dynamic model of the UAV hoisting system, construct the dynamic equations for hoisting the UAV using a variable rope length two-stage pendulum, and write the energy coupling relationship between the UAV, the hook, and the load;

[0055] Step 3, a smooth expected positioning trajectory is selected to ensure smooth operation of the UAV, and a system generalized load signal is constructed to improve the anti-interference ability of the system, the system generalized load signal containing UAV displacement and swing angle signals, and a generalized displacement tracking error signal can be obtained;

[0056] Step 4, according to the dynamic model of the UAV hoisting system, a swing elimination controller is designed, and the obtained controller can make the UAV hoisting transportation system have the advantages of precise positioning and swing angle anti-swing;

[0057] Step 5, combining the UAV position information, swing angle information and the swing elimination controller to obtain an input signal, under the driving of the input signal, the dual goals of UAV positioning and load and hook swing elimination are completed.

[0058] In this embodiment, the hardware structure of the flight hoisting system with double-swing swing effect includes a UAV body, a hook and a load, and a hoisting rope between the UAV and the hook, and a hoisting rope between the hook and the load.

[0059] The variable rope length two-stage swing hoisting UAV dynamic equation constructed according to the Lagrange dynamics equation in step 2 is as follows:

[0060]

[0061] In combination Figure 1 , is the inertial coordinate system, is the body coordinate system.

[0062] In the formula , and are the mass of the UAV, the mass of the hook and the mass of the load, and respectively represent the length of the hoisting rope, and respectively represent the swing angle of the hook and the load, is the gravitational acceleration, is the resultant force applied to the UAV, is the direction driving force.

[0063] In step 3, after selecting a smooth expected positioning trajectory, in order to improve the anti-interference ability of the system, a system generalized load signal is constructed, which contains UAV displacement and swing angle signals:

[0064]

[0065]

[0066] wherein ∈ R+, , , is a positive gain.

[0067] The error signal vector is then represented as:

[0068]

[0069] wherein is x the desired trajectory in the direction, is z the desired trajectory in the direction.

[0070] The two-stage swing angles satisfy:

[0071]

[0072] The rope motor driving force is limited:

[0073] Rope always satisfies:

[0074] Thus, the generalized displacement tracking error signal

[0075]

[0076] wherein,

[0077] ,

[0078]

[0079] For convenience of calculation and stability analysis, the variable rope length two-stage swing unmanned aerial vehicle dynamics equation is rewritten in matrix form: .

[0080] wherein, , , , , are the inertia matrix, the centripetal force matrix, the gravity vector, the driving vector, and the disturbance vector of the system, respectively.

[0081] The matrix specific expression is as follows:

[0082] ,

[0083] ,

[0084] ,

[0085] ,

[0086] wherein , , , ,

[0087] , , , ,

[0088] , , , , ,

[0089] , , , ,

[0090] , , , ,

[0091] , , , ,

[0092] .

[0093] represents , represents , represents , represents .

[0094] The sway control law of the sway controller in Step 4:

[0095]

[0096] wherein , , , , , is a gain;

[0097] The sway control law can ensure that the UAV reaches a specified position ; the length of the sling reaches a specified length ; the swing angle of the hook and the load can be effectively inhibited, the control law meets the system stability requirement, that is, the system should meet:

[0098]

[0099] In the formula, is the target position in the x direction, is the target position in the z direction, is the target length of the sling.

[0100] By using the Lyapunov method and the Barbara lemma, the following is obtained

[0101] Derivation and limit for time can obtain

[0102]

[0103] The following can be obtained in combination

[0104] .

[0105] As described above, it is proved that

[0106] The conclusion is correct.

[0107] The control law meets the system stability requirement.

[0108] The smooth expected positioning trajectory described in step 3 is:

[0109]

[0110] In the formula , is the positioning part trajectory, , the specified position to which it must converge, and epsilon is the initial acceleration adjustment parameter, , , , is the gain.

[0111] In the embodiment, under the driving of the above control input signal, the dual goals of unmanned aerial vehicle positioning and load and hook swing elimination are achieved.

[0112] To verify the effectiveness of the controller designed in the disclosure, the above steps can be performed on the self-built platform. The invention uses the matlab / simulink experimental simulation platform to build a variable rope length two-stage swing crane unmanned aerial vehicle simulation model, and analyzes the positioning and swing elimination performance of the system through numerical simulation. The main parameters of the simulation model are:

[0113] M =10kg, =1kg, =2kg, =1m, =0.2m,g=9.8m / s 2 , ε=3

[0114] Positioning trajectory displacement =2m and =2m

[0115] Generalized load signal gain

[0116] Anti-swing controller gain

[0117] Wind resistance coefficient

[0118] Rope friction coefficient

[0119] Desired trajectory gain

[0120] The results are shown in Figures 2-6. As can be seen from the comparison curves in the figures, compared with the other two control methods, the method can make the unmanned aerial vehicle reach the specified position faster. In terms of swing elimination, the conventional PID and the conventional energy coupling have a higher swing frequency and a larger swing amplitude. The control method has better performance in swing elimination, can quickly and effectively suppress the swing angle of the hook and the load, and eliminate the residual swing angle.

[0121] As shown in Figures 7-11. At 12-14s, a 4° sinusoidal disturbance signal is added, and after the disturbance disappears, the system can eliminate the swing angle caused by external disturbance within 2s. It shows that the control method proposed in this paper has strong robustness and can effectively suppress the influence caused by external disturbance, so that the system quickly recovers stability.

[0122] Embodiment 2:

[0123] The embodiment provides an electronic device, which comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the two-stage swing anti-swing control method of the hoisting unmanned aerial vehicle according to the embodiment 1 when executing the program.

[0124] Embodiment 3:

[0125] The embodiment provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to implement the two-stage swing anti-swing control method of the hoisting unmanned aerial vehicle according to the embodiment 1.

[0126] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical contents to obtain equivalent embodiments with equivalent changes, without departing from the technical solution of the present application. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application should be covered within the protection scope of the present application.

Claims

1. A method for anti-swing control of a secondary swing of a hoisting drone, characterized in that : The method comprises the following steps: Step 1, constructing the hardware structure of the unmanned aerial vehicle hoisting system with the variable rope length two-stage pendulum swing effect; Step 2, constructing the dynamic equation of the variable rope length two-stage pendulum hoisted unmanned aerial vehicle based on the dynamic model of the unmanned aerial vehicle hoisting system; Step 3, selecting a smooth expected positioning trajectory to ensure the smooth operation of the unmanned aerial vehicle; Step 4, designing a pendulum elimination controller according to the dynamic model of the unmanned aerial vehicle hoisting system; Step 5, obtaining an input signal in combination of the unmanned aerial vehicle position information, the pendulum angle information and the pendulum elimination controller, and completing the dual goals of unmanned aerial vehicle positioning and load and hook pendulum elimination under the driving of the input signal; The dynamic equation of the variable rope length two-stage pendulum hoisted unmanned aerial vehicle in step 2 is: wherein , and are the mass of the drone, the mass of the hook and the mass of the load, and denote the length of the hoisting rope, and denote the swing angle of the hook and the load, is the acceleration of gravity, is the resultant force applied to the drone, is the direction driving force on the ; The pendulum elimination control law of the pendulum elimination controller in step 4 is: In the formula For gain; The swing control law can ensure that the unmanned aerial vehicle reaches a specified position ; the length of the hoisting rope reaches a specified length ; the swing angle of the hook and the load can be effectively suppressed, and the control law meets the system stability requirements, that is, the system should meet: In the formula, is a target position in the x direction, is a target position in the z direction, is a target length of the sling.

2. The two-stage swing prevention control method for the hoisting drone according to claim 1, characterized in that The smooth expected positioning trajectory in step 3 is: wherein , is a specified position to which the portion of the trajectory must converge, , is an initial acceleration adjustment parameter, , , , is a gain.

3. The two-stage swing prevention control method for the hoisting drone according to claim 1, characterized in that After selecting a smooth expected positioning trajectory in step 3, in order to improve the anti-interference ability of the system, a system generalized load signal is constructed, and the system generalized load signal comprises the unmanned aerial vehicle displacement and the pendulum angle signal: wherein , , 、 are all positive gains.

4. The two-stage swing prevention control method for the hoisting drone according to claim 3, characterized in that The dynamic equation of the variable rope length two-stage pendulum suspension unmanned aerial vehicle is rewritten in matrix form: ; where , , , , are the system's inertia matrix, centripetal matrix, gravity vector, drive vector, and disturbance vector, respectively.

5. The two-stage swing prevention control method for the hoisting drone according to claim 1, characterized in that The hardware structure of the unmanned aerial vehicle hoisting system in step 1 comprises the unmanned aerial vehicle body, the hook and the load, and the hoisting rope between the unmanned aerial vehicle and the hook and the hoisting rope between the hook and the load.

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