An airborne composite cable tension control method

Abstract

The application relates to an airborne composite cable tension control method, and belongs to the technical field of aviation flight.The method steps are as follows: a two-dimensional composite cable damping-spring model is established; a two-dimensional coordinate system of the composite cable damping-spring model is established; a composite cable dynamics model is established; a test target object dynamics model is established; a test target object surface wall pressure distribution diagram is obtained; micro-element stress distribution diagrams of the composite cable at different positions under different working conditions are obtained; a power motor control model is constructed; stress fluctuation curves of the composite cable and the connection position of a mother machine are input into the power motor control model, speed and position control instructions of a direct-current brushless motor are obtained, the control instructions are executed by the direct-current brushless motor, action control of composite cable retraction and release is completed, and airborne composite cable tension control is completed.The control mode of the application is optimized, and compared with a traditional observer, an error is reduced by 26.45%, and the position and speed tracking effect is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aviation flight, and particularly relates to an airborne composite cable tension control method. BACKGROUND

[0002] The photoelectric composite cable device mainly uses a customized photoelectric composite cable to provide high-strength towing and traction between the aircraft and the test target object. During the flight task execution, the photoelectric composite cable device controls the rotation of the winding winch to realize the unwinding and winding of the photoelectric composite cable, and thus realizes the unwinding and winding of the test target object.

[0003] The tow cable is an important bridge connecting the test target object and the mother machine, and is a kind of excellent structural component mainly bearing tension in the system. For the airborne test target object unwinding and winding system, the tow cable is generally composed of a steel cable or a photoelectric composite cable, both of which have the characteristics of "tensionable and incompressible". The mother machine often makes some maneuvering postures, and due to the interference of acceleration, the tension on the tow cable will increase sharply, which greatly endangers the safety of the test target object and the tow cable, and the excessive tension will damage the structure. If the test target object is unwound from the tail of the aircraft, the influence of the turbulence at the tail of the aircraft will cause the tension on the tow cable to decrease, and the small tension will cause the displacement of the winch unwinding the tow cable to be smaller than the actual displacement of the test target object unwinding, and the tow cable will accumulate in the cabin, causing the photoelectric composite cable to break or damage other equipment. In order to ensure that the tension of the composite cable towing the test target object remains within a certain safe range when the aircraft makes maneuvering actions, it is necessary to develop an airborne composite cable tension control method to ensure the safety and stability of the composite cable during the unwinding and winding of the test target object and the maneuvering of the aircraft.

[0004] Currently, the cable releasing and collecting device disclosed by the prior art mainly consists of a slide rail, a lead screw, a winding wheel and a driving wheel. There are two modes of operation, i.e. releasing and collecting. When releasing, the lead screw starts to rotate, drives the winding group and the second limiting cover to move linearly under the restriction of the lead screw and the slide rail to approach the first limiting cover; at the same time, the driving wheel starts to operate, the cable is dragged out by the test target, the cable tension drives the winding wheel to rotate; finally, the cable is released under the coordination of the lead screw and the driving wheel, the test target is quickly released; lubricating grease is applied between the second limiting cover and the slide rail to reduce the sliding friction therebetween, so that the second limiting cover slides more smoothly. When collecting, the lead screw starts to rotate, drives the winding group and the second limiting cover to move linearly under the restriction of the lead screw and the slide rail to move away from the first limiting cover; at the same time, the driving wheel starts to operate, the winding wheel rotates to drive the cable to be regularly wound on the cable groove, the cable tension pulls the test target to move towards the device; finally, the cable is collected under the coordination of the lead screw and the driving wheel, the test target is collected. The driving wheel and the lead screw are driven by numerical control motors to accurately control the releasing and collecting speed. The cable tension control loop of the device has the following problems: low intelligentization; the system does not add a numerical control motor control algorithm, only uses a simple releasing and collecting logic for operation, does not constitute a closed loop system based on a traction cable, and is prone to cause the cable tension to exceed the threshold value, which is unstable.

[0005] The existing technology discloses a towing device mainly consisting of a traction winch, a tensioning winch, a guide pulley set and an electrical system. The traction method steps consist of a system starting and tension reduction stage, an acceleration stage, a constant speed stage, a deceleration stage and an accurate tension parking. According to the above steps, the control system realizes self-adaptive collaborative control of the traction winch and the tensioning winch through a PID self-adaptive controller. The problems in the dynamic modeling are that the instability and randomness caused by ocean waves are not analyzed enough; the control stability is poor. SUMMARY

[0006] The technical problem to be solved is:

[0007] In order to avoid the shortcomings of the prior art, the present application provides an airborne composite cable tension control method, which firstly builds a dynamic model of the test target and the composite cable, secondly analyzes the model by finite element analysis to obtain the stress change curve of the composite cable under different working conditions; and by establishing an inductionless vector control model of the dynamic motor, the observer applies a second-order generalized integrator cascaded with a single-frequency notch filter to the position observation loop to replace the traditional method. The present application proves that each part of the structure is within the limit stress of its material based on the working condition, meets the engineering deformation requirement, and proves the reliability of the structure in the process of the aircraft maneuvering. After the control mode is optimized, the error is reduced by 26.45% compared with the traditional observer, and the present application effectively improves the position and speed tracking effect.

[0008] The technical scheme of the present application is: an airborne composite cable tension control method, characterized by the following specific steps:

[0009] A two-dimensional composite cable damping-spring model is established, and the composite cable damping-spring model is discretized into a plurality of microelements;

[0010] A two-dimensional coordinate system of the composite cable damping-spring model is established, and the plane of the two-dimensional coordinate system is perpendicular to the ground;

[0011] Dynamics calculation is performed on the composite cable damping-spring model to obtain a composite cable dynamics model;

[0012] Based on the composite cable dynamics model, a test target object dynamics model is established; the head direction vector of the test target object and the direction vector of the last microelement of the composite cable point in the same direction;

[0013] Based on the test target object dynamics model, steady-state analysis is performed on a test target object simulation model to obtain a test target object surface wall pressure distribution diagram and a surface velocity streamline distribution cloud diagram;

[0014] Based on the composite cable dynamics model, the test target object dynamics model, the test target object surface wall pressure distribution diagram, and the surface velocity streamline distribution cloud diagram, transient analysis is performed on the composite cable damping-spring model to obtain a microelement stress distribution diagram of the composite cable at different positions under different working conditions;

[0015] A dynamic motor control model is constructed; the stress fluctuation curve at the connection between the composite cable and the parent machine is input into the dynamic motor control model to obtain a speed and position control instruction for the direct-current brushless motor, the control instruction is executed by the direct-current brushless motor, the action control of the composite cable retraction and release is completed, and the airborne composite cable tension control is completed.

[0016] A further technical scheme of the present application is: the mass of each microelement in the two-dimensional composite cable damping-spring model is concentrated at the end thereof, and each microelement is defined as a node of the composite cable, i.e., a composite cable damping-spring model in which the nodes are connected by springs is obtained; the composite cable damping-spring model can only bear tension and cannot bear pressure.

[0017] A further technical scheme of the present application is: the two-dimensional coordinate system is O-XY; let the coordinate of the jth node of the composite cable damping-spring model be r j =[x j ,y j ], the differential is obtained as the node velocity v j , and the differential of the node velocity is obtained as the node acceleration a j , and the formula is as follows:

[0018]

[0019] wherein, is the elastic force vector; is the damping force vector; is the gravity force vector; is the aerodynamic force vector.

[0020] A further technical solution of the present application is that the formula of the composite cable dynamics model is as follows:

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] wherein, Q j is the position vector of the jth node, E is the elastic modulus of the rope, A is the cross-sectional area of the rope, LS j is the length of the jth segment of the microelement rear rope, r f is the position vector of the rope head and the connection of the aircraft, C is the damping force coefficient of the rope microelement, m j is the mass of the jth segment of the cable microelement, ρ is the air density of the current microelement segment, C D is the air resistance coefficient vector, S is the effective windward area vector, and V is the velocity vector.

[0027] A further technical solution of the present application is that the resultant force on the test target object includes its own gravity, air resistance and the traction of the composite cable; the formula of the test target object dynamics model is as follows:

[0028]

[0029]

[0030] wherein, Q1 is the position vector of the first node of the composite cable damping-spring model, and the first node is connected with the test target object; Q D is the position vector of the last node of the composite cable damping-spring model, and the last node is connected with the mother machine; r D is the position vector of the test target object warhead and the cable connection; m d is the mass of the test target object; a d is the acceleration of the test target object; is the gravity of the test target object itself; is the air resistance on the test target object; To test the target object is subjected to traction from the end of the cable.

[0031] A further technical solution of the present application is that the method for obtaining the surface wall pressure distribution map and the surface speed streamline distribution cloud map of the test target object is,

[0032] According to the dynamic model of the test target object, a simulation model of the test target object is constructed;

[0033] The simulation model of the test target object is imported into the COMSOL and Catia environment, and the test target object is analyzed to obtain the surface wall pressure distribution map and the surface speed streamline distribution cloud map of the test target object.

[0034] The steady-state analysis adopts the turbulent flow k-ε (spf) model for calculation, and the turbulent kinetic energy transport equation is as follows:

[0035]

[0036] Wherein, is a turbulent kinetic energy generation term, which represents the energy transfer from the average kinetic energy to the fluctuating kinetic energy due to shear action; is a diffusion term, which represents the diffusion effect of turbulent flow; is a dissipation term, which represents the dissipation rate of turbulent kinetic energy due to viscosity; k is the turbulent kinetic energy; t is time; u is the velocity vector; x is the spatial coordinate; ρ is the fluid density; v is the turbulent kinetic energy diffusion coefficient generated by molecular viscosity.

[0037] A further technical solution of the present application is that the method for obtaining the micro-element stress distribution map of the composite cable at different positions under different working conditions is:

[0038] According to the dynamic model of the test target object, a simulation model of the test target object is constructed;

[0039] The simulation model of the composite cable connected with the test target object is imported into the Visual studio+Intel visualFortran+Abaqus / CAE environment, the corresponding parameters are set, and the UAMP user subroutine is used for secondary development to perform transient analysis on the composite cable.

[0040] The simulation model of the composite cable with the target object is solved in Abaqus using the Standard solver to obtain the node stress map at different positions under different working conditions.

[0041] A further technical solution of the present application is that the dynamic motor control model includes a motor position loop control calculation module, a sine wave vibration pulse high-frequency injection model and a non-inductive observer model, which can realize optimization based on a filter speed position observation loop.

[0042] The motor position loop control calculation module obtains the load torque of the motor through the node stress coupling calculation of the composite cable and the connection of the mother machine, and timely releases the stress accumulation in the composite cable by adjusting the motor position during the retraction and release of the composite cable.

[0043] The sinusoidal wave vibration pulse high-frequency injection model is used for injecting a high-frequency sinusoidal voltage signal into the direct axis direction of the direct-current brushless motor to excite the saturation salient-pole effect of the motor.

[0044] The non-inductive observer model extracts the response current from the cross axis of the direct-current brushless motor and realizes the estimation of the speed and position through signal modulation and demodulation, and feeds back the estimated rotor angle to the FOC coordinate transformation.

[0045] A further technical solution of the application is that the non-inductive observer model applies a second-order generalized integrator and a single-frequency notch filter to the position observation loop, and adopts a position error extraction strategy based on SOGI cascaded NOTCH to obtain position error information.

[0046] A further technical solution of the application is that the specific steps of the position error extraction strategy based on SOGI cascaded NOTCH are as follows:

[0047] A high-frequency voltage signal is injected into the direct axis of the direct-current brushless motor; the high-frequency signal can obtain a current signal containing position information through the internal reaction of the motor;

[0048] The required current signal is extracted through the SOGI filter, and the filtered current signal is demodulated by using the multiplier;

[0049] The demodulated current signal is extracted by the NOTCH filter and used as the input signal of the position estimator;

[0050] The position error information is outputted through the position estimator.

[0051] Beneficial effects

[0052] The beneficial effects of the application are that the airborne composite cable tension control method considers the problems of the composite cable tension exceeding the threshold value when the aircraft is maneuvering, the unstable motor speed when the composite cable is retracted and released, and the lack of dynamic model analysis in the traditional airborne test target object retracting and releasing system. The airborne composite cable tension control model is established. In order to improve the control stability of the traditional retracting and releasing system, the dynamic model of the composite cable and the test target object is established in advance for stress analysis. In addition, the dynamic motor control model is designed, which reduces the influence of the composite cable tension exceeding the threshold value on the system, and greatly improves the stability of the system operation.

[0053] After simulation calculation verification, the head of the test target object adopts an aviation aluminum alloy, the tail adopts an engineering plastic, a signal generating part is placed in the hollow inside the test target object, the surface speed flow line of the test target object, the surface wall pressure and the transient stress curve of the composite cable under different working environments are calculated by using finite element analysis, the surface speed flow line and the wall pressure distribution cloud diagram of the test target object are as shown in Figures 1-2 The composite cable transient stress curve is as shown in Figures 3-5 The analysis simulation result shows that the structures of each part based on the above working conditions are within the limit stress of the material, meet the engineering deformation requirements, and prove the reliability of the structure in the process of the aircraft maneuvering.

[0054] When the traditional position observer is used, a band-pass filter cascaded with a low-pass filter is applied to the position observation loop, the direct-current brushless motor low-speed mode is used, the average error of the speed tracking calculation within 9 seconds obtained under the actual working condition is 0.08353 r / min; a comparison test group is set, the position observer uses a second-order generalized integrator cascaded with a low-pass filter, the average error of the speed tracking calculation within 9 seconds obtained under the actual working condition is 0.09719 r / min; the position observer using the second-order generalized integrator cascaded with the single-frequency notch filter after optimization in the application has the average error of the speed tracking calculation within 9 seconds obtained under the actual working condition is 0.06144 r / min. Compared with the traditional observer, the error is reduced by 26.45%, that is, the technical scheme of the application has better position and speed tracking effect than the traditional filter cascaded group.

[0055] The technical scheme of the application is compared with the control effect of the traditional observer.

[0056] BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 It is the surface speed flow line distribution cloud diagram of the test target object according to the embodiment of the application;

[0058] Figure 2 It is the surface wall pressure distribution cloud diagram of the test target object according to the embodiment of the application;

[0059] Figure 3 It is the stress comparison analysis curve of the composite cable when the aircraft uniformly accelerates and linearly maneuvers under different acceleration loads according to the embodiment of the application;

[0060] Figure 4 It is the stress comparison analysis curve of the composite cable when the aircraft uniformly accelerates and linearly maneuvers under different altitudes according to the embodiment of the application;

[0061] Figure 5 It is the stress comparison analysis curve of the composite cable when the aircraft uniformly accelerates and linearly maneuvers under different composite cable position nodes according to the embodiment of the application;

[0062] Figure 6 is a schematic diagram of a second-order generalized integrator cascade single-frequency notch filter position observation loop structure according to the present application;

[0063] Figure 7 is a schematic diagram of the method according to the present application. DETAILED DESCRIPTION

[0064] The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0065] Based on the poor stability of the existing cable towing device in cable paying-off control, the present application provides an airborne composite cable tension control method, and the specific steps are as follows:

[0066] Step 1: a two-dimensional composite cable damping-spring model is established, and the composite cable damping-spring model is discretized into a plurality of microelements;

[0067] Step 2: a two-dimensional coordinate system of the composite cable damping-spring model is established, and the plane where the two-dimensional coordinate system is located is perpendicular to the ground;

[0068] Step 3: dynamic calculation is performed on the composite cable damping-spring model to obtain a composite cable dynamic model;

[0069] Step 4: based on the composite cable dynamic model, a test target object dynamic model is established; the head direction vector of the test target object and the direction vector of the last microelement of the composite cable point in the same direction;

[0070] Step 5: based on the test target object dynamic model, steady-state analysis is performed on a test target object simulation model to obtain a test target object surface wall pressure distribution diagram and a surface velocity flow line distribution cloud diagram;

[0071] Step 6: based on the composite cable dynamic model, the test target object dynamic model, the test target object surface wall pressure distribution diagram and the surface velocity flow line distribution cloud diagram, transient analysis is performed on the composite cable damping-spring model to obtain a microelement stress distribution diagram of the composite cable at different positions under different working conditions;

[0072] Step 7: a dynamic motor control model is constructed; the stress fluctuation curve of the connection between the composite cable and the mother machine is input into the dynamic motor control model to obtain a speed and position control instruction of the direct-current brushless motor, the control instruction is executed by the direct-current brushless motor, the action control of the composite cable retraction and paying-off is completed, and the airborne composite cable tension control is completed.

[0073] The application firstly establishes a composite cable and test target object dynamics model for stress analysis, and secondly designs a dynamic motor control model, thereby reducing the influence of the composite cable tension exceeding the threshold on the system and greatly improving the stability of the system.

[0074] The above technical solutions are further described below with reference to the accompanying drawings:

[0075] As shown in the figure, the embodiment of the airborne composite cable tension control method is specifically implemented according to the following steps: Figure 7

[0076] Step 1: Establish a two-dimensional composite cable damping-spring model;

[0077] According to the multi-flexible body dynamics characteristics of the rope system, it is planned to use the finite segment method to establish a two-dimensional composite cable damping-spring model; the composite cable is discretized into a certain number of microelements from the rope head segment to the tail end, and the mass of each microelement is concentrated at the end points adjacent to the microelement.

[0078] In the discretized model, only the axial elongation of the rope segment is considered without considering the bending of the rope segment, it can be assumed that the nodes of the rope segment are connected by a “spring”, and the “spring” can only bear tension and cannot bear pressure, and considering the damping effect of the rope, the rope segment is treated as a concentrated mass damping spring with mass concentrated at the two end points of the rope segment.

[0079] Step 2: Establish a two-dimensional coordinate system of the composite cable damping-spring model;

[0080] Based on the composite cable damping-spring model established in step 1, only the model in the two-dimensional coordinate system perpendicular to the ground is considered, and a two-dimensional inertial coordinate system is established with a point on the ground as the origin.

[0081] Step 3: Establish a composite cable dynamics model;

[0082] The gravity, aerodynamic force, elastic force and damping force vectors of each node of the two-dimensional composite cable damping-spring model are calculated respectively to obtain the composite cable dynamics model.

[0083] Step 4: Establish a test target object dynamics model;

[0084] The composite cable dynamics model obtained in step 3 is used to analyze the dynamics characteristics of the test target object, and the test target object dynamics model is established accordingly. The direction vector of the test target object warhead points in the same direction as the direction vector of the last microelement of the cable, and the test target object is subjected to the combined force of its own gravity, air resistance and the traction force of the composite cable.

[0085] Step 5: Obtain the test target object surface wall pressure distribution diagram and

[0086] ​According to the test target object dynamic model established in step 4, the test target object model is studied in a steady state, and a test target object surface wall pressure distribution diagram and a test target object surface velocity stream line distribution cloud diagram are obtained.

[0087] Step 6: Obtain the microelement stress distribution diagram of the composite cable at different positions under different working conditions.

[0088] Based on the composite cable dynamic model, the test target object dynamic model and the test target object surface wall pressure distribution diagram, the composite cable model is analyzed in a transient state, and the node stress size of the composite cable at different altitudes, different accelerations of the carrier and different positions of the composite cable is analyzed.

[0089] Step 7: Construct a dynamic motor control model to complete the control of the airborne composite cable tension.

[0090] According to the node stress distribution diagram of the composite cable and the test target object at different altitudes, different accelerations of the carrier and different positions of the composite cable obtained in step 6, the stress fluctuation curve of the composite cable and the parent machine connection is obtained; the stress fluctuation curve of the composite cable and the aircraft connection is input into the dynamic motor control model to obtain the control of the speed and position of the direct current brushless motor, and then the optimization of the retraction and release action of the composite cable is completed; and in the case of stress change of the composite cable due to the maneuvering action of the carrier, a better dynamic response is obtained. After the composite cable is released to a fixed distance, the control algorithm is used to change the rotating position of the direct current brushless motor to indirectly release the stress accumulation in the composite cable.

[0091] The airborne composite cable tension control method will be further described in detail through specific embodiments.

[0092] The two-dimensional inertial coordinate system established in step 2 of the embodiment is O-XY. The cable is connected by nodes, and the coordinate of the jth node is r j =[x j ,y j ], the differential of which is the node velocity v j , and the differential of the node velocity is the node acceleration a j . The specific formula is as follows:

[0093]

[0094] Among them, is the elastic force vector; is the damping force vector; is the gravity vector; is the aerodynamic force vector.

[0095] The force vector borne by each node of the composite cable established in step 3 of the embodiment is as follows:

[0096]

[0097]

[0098]

[0099]

[0100] where E is the elastic modulus of the rope, A is the cross-sectional area of the rope, LS j is the length of the jth segment of the rear rope, r f is the position vector of the connection between the front end of the rope and the aircraft, C is the damping force coefficient at the cable microelement, m j is the mass of the jth segment of the cable microelement, p is the air density of the current microelement segment, C D is the air resistance coefficient vector, S is the effective wind area vector, and V is the velocity vector.

[0101] The test target object dynamics model established in step 4 of the embodiment is as follows:

[0102]

[0103]

[0104] where r D is the position vector of the connection between the warhead of the test target object and the cable, m d is the mass of the test target object; a d is the acceleration of the test target object; is the gravity of the test target object itself; is the air resistance received by the test target object; is the traction force received by the test target object from the end of the cable.

[0105] Referring to Figures 1-2 , in step 5 of the embodiment, a physical simulation model of the test target object is constructed according to the test target object dynamics model; and then the physical simulation model of the test target object is imported into Comsol6.14 and Catia2020V5 environments to perform steady-state analysis on the test target object model, and a test target object surface wall pressure distribution diagram is obtained.

[0106] In the steady-state analysis, the turbulent flow k-ε(spf) model is used for calculation, and the turbulent kinetic energy transport equation is specifically as formula (20).

[0107]

[0108] where, is the turbulent kinetic energy generation term, which represents the energy transfer from the average kinetic energy to the fluctuating kinetic energy due to shear action; is the diffusion term, which represents the diffusion effect of the turbulent flow; is the dissipation term, which represents the dissipation rate of the turbulent kinetic energy due to viscosity.

[0109] With reference to Figures 3-5 In step 6 of the embodiment, a simulation model of the composite cable connected with the test target object is constructed according to a dynamic model of the composite cable and a dynamic model of the test target object; the simulation model of the composite cable connected with the test target object is imported into a Visual studio 2019 Professional (English version) + Intel visual Fortran 11.1.065 + Abaqus / CAE 2020 environment, corresponding parameters are set, the initial speed of the carrier is set to 100 m / s, the flight altitude is set to 6 km, and stress analysis is performed on the composite cable when the carrier is uniformly accelerated at 10 m / s 2 , 20 m / s 2 and 30 m / s 2 ; when the carrier is accelerated at 10 m / s 2 , stress analysis is performed on the composite cable at flight altitudes of 2 km, 4 km and 6 km, respectively; when the carrier is accelerated at 10 m / s 2 , the flight altitude is 6 km, and stress analysis is performed on the nodes at 0%, 20%, 40%, 60%, 80% and 100% of the length of the composite cable, respectively. Secondary development is performed on the composite cable by using a UAMP user subroutine for transient analysis; the simulation model of the composite cable with the target object is solved by using a Standard solver in Abaqus, and node stress diagrams at different positions under different working conditions are obtained.

[0110] In step 7 of the embodiment, the motor control model comprises a motor position loop control calculation module, a sinusoidal vibration pulse high-frequency injection model and a non-inductive observer model, and can realize optimization based on a filter speed position observation loop;

[0111] The motor position loop control calculation module obtains the load torque of the motor by coupling calculation of the node stress at the connection between the composite cable and the parent machine, and timely releases the stress accumulation in the composite cable by adjusting the motor position during the retraction and release of the composite cable.

[0112] The sinusoidal vibration pulse high-frequency injection model is used to inject a high-frequency sinusoidal voltage signal into the direct-axis direction of the direct-current brushless motor to excite the saturation salient-pole effect of the motor.

[0113] The non-inductive observer model extracts the response current from the quadrature axis and realizes the estimation of the speed and position through signal modulation and demodulation, and feeds back the estimated rotor angle to the FOC coordinate transformation.

[0114] With reference to Figure 6As shown in the figure, the sensorless observer model applies a second-order generalized integrator and a single-frequency notch filter to the position observation loop, replacing the traditional BPF+LPF mode. A position error extraction strategy based on SOGI cascade NOTCH is proposed. The specific steps of obtaining position error information using the position error extraction strategy based on SOGI cascade NOTCH are as follows:

[0115] Step 1: Inject a high-frequency voltage signal into the direct axis of the brushless DC motor. The high-frequency signal reacts inside the motor to generate a current signal containing position information.

[0116] Step 2: Extract the desired current signal through the SOGI filter and then demodulate the filtered current signal using a multiplier.

[0117] Step 3: Extract the demodulated current signal through the NOTCH filter as the input signal of the position estimator;

[0118] Step 4: Output the position error information through the position estimator (phase-locked loop).

[0119] When a traditional position observer is used, a bandpass filter cascaded with a low-pass filter is applied to the position observation loop, and the DC brushless motor is used in low-speed mode. The average error of the speed tracking calculation within 9 seconds under actual working conditions is 0.08353 r / min. A comparative test group is set up, and the position observer adopts a second-order generalized integrator cascaded with a low-pass filter. The average error of the speed tracking calculation within 9 seconds under actual working conditions is 0.09719 r / min. The optimized position observer composed of a second-order generalized integrator cascaded with a single-frequency notch filter in the present invention has an average error of 0.06144 r / min in actual working conditions. Compared with the traditional observer, the error is reduced by 26.45%, that is, the technical solution of the present invention has better position and speed tracking effect than the traditional filter cascade group.

[0120] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A method for controlling the tension of an airborne composite cable, characterized in that The specific steps are as follows: Establishing a two-dimensional composite cable damping-spring model, and discretizing the composite cable damping-spring model into a plurality of infinitesimal elements; Establishing a two-dimensional coordinate system of the composite cable damping-spring model, wherein the plane of the two-dimensional coordinate system is perpendicular to the ground; Performing dynamic calculation on the composite cable damping-spring model to obtain a composite cable dynamic model; Based on the composite cable dynamics model, a test target dynamics model is established; the head direction vector of the test target is in the same direction as the direction vector of the last infinitesimal element of the composite cable; Based on the dynamic model of the test target object, a steady-state analysis is performed on the simulation model of the test target object to obtain a surface pressure distribution diagram and a surface velocity streamline distribution cloud diagram of the test target object; Based on the composite cable dynamics model, the test target dynamics model, the test target surface wall pressure distribution map and the surface velocity streamline distribution cloud map, a transient analysis of the composite cable damping-spring model is performed to obtain microelement stress distribution maps at different positions of the composite cable under different working conditions; Construct a power motor control model; input the stress fluctuation curve at the connection between the composite cable and the mother machine into the power motor control model to obtain the speed and position control instructions for the DC brushless motor. The DC brushless motor executes the control instructions to complete the action control of retracting and releasing the composite cable, that is, to complete the tension control of the onboard composite cable.

2. The method for controlling the tension of an airborne composite cable according to claim 1, wherein: The mass of each microelement in the two-dimensional composite cable damping-spring model is concentrated at its end, and each microelement is defined as a node of the composite cable, that is, a composite cable damping-spring model in which each node is connected by a spring is obtained; the composite cable damping-spring model can only withstand tension but not compression.

3. The method for controlling the tension of an airborne composite cable according to claim 2, wherein: The two-dimensional coordinate system is O-XY; let the coordinate of the jth node of the composite cable damping-spring model be r j =[x j ,y j ], differentiate and get the node velocity v j , and then differentiate the node velocity to get the node acceleration a j , the formula is as follows: in, is the elastic force vector; is the damping force vector; is the gravity vector; is the aerodynamic force vector.

4. The method for controlling the tension of an airborne composite cable according to claim 3, wherein: The formula of the composite cable dynamic model is as follows: Among them, Q j is the position vector of the jth node, E is the elastic modulus of the rope, A is the cross-sectional area of ​​the rope, LS j is the length of the jth section of the rope after the infinitesimal element, r f is the position vector of the connection between the rope head and the carrier, C is the damping force coefficient at the rope microelement, m j is the mass of the jth segment after the cable infinitesimal element, ρ is the air density of the environment where the current infinitesimal segment is located, C D is the air resistance coefficient vector, S is the effective frontal area vector, and V is the velocity vector.

5. The method for controlling the tension of an airborne composite cable according to claim 4, wherein: The resultant force on the test object includes its own gravity, air resistance, and the traction force of the composite cable. The formula of the test object dynamic model is as follows: Where Q1 is the position vector of the first node of the composite cable damping-spring model, which is connected to the test object; Q D is the position vector of the last node of the composite cable damping-spring model, which is connected to the mother machine; r D is the position vector of the connection between the warhead of the test target and the cable; m d is the mass of the test object; a d is the acceleration of the test object; To test the target's own gravity; The air resistance of the test object; The test target is subjected to a pulling force from the end of the cable.

6. The method for controlling the tension of an airborne composite cable according to claim 5, wherein: The method for obtaining the surface pressure distribution map and surface velocity streamline distribution cloud map of the test target object is as follows: Construct a simulation model of the test target according to the dynamic model of the test target; The simulation model of the test target is imported into COMSOL and Catia environments, and a steady-state analysis is performed on the test target to obtain the surface wall pressure distribution map and surface velocity streamline distribution cloud map of the test target. The steady-state analysis is calculated using the turbulent k-ε (spf) model, and the turbulent kinetic energy transport equation is as follows: in, is the turbulent kinetic energy generation term, which represents the energy transfer from average kinetic energy to pulsating kinetic energy due to shearing; is the diffusion term, which represents the diffusion effect of turbulence; is the dissipation term, which represents the dissipation rate of turbulent kinetic energy caused by viscosity; k is the turbulent kinetic energy; t is time; u is the velocity vector; x is the spatial coordinate; ρ is the fluid density; and v is the turbulent kinetic energy diffusion coefficient caused by molecular viscosity.

7. The method for controlling the tension of an airborne composite cable according to claim 6, wherein: The method for obtaining the microelement stress distribution diagram at different positions of the composite cable under different working conditions is as follows: A composite cable simulation model connected to a test target is constructed based on the composite cable dynamics model and the test target dynamics model; The simulation model of the composite cable connected to the test target was imported into the Visual studio+Intel visual Fortran+Abaqus / CAE environment, the corresponding parameters were set, and the UAMP user subroutine was used for secondary development to perform transient analysis on the composite cable. The Standard solver is used in Abaqus to solve the composite cable simulation model with the target object, and the stress diagrams of the nodes at different positions under different working conditions are obtained.

8. The method for controlling the tension of an airborne composite cable according to claim 7, wherein: The power motor control model includes a motor position loop control calculation module, a sinusoidal wave pulse high-frequency injection model and a sensorless observer model, which can realize filter-based speed position observation loop optimization; The motor position loop control calculation module obtains the load torque of the motor through the node stress coupling calculation at the connection between the composite cable and the mother machine, and timely releases the stress accumulation in the composite cable by adjusting the motor position during the composite cable retraction and release process; The sinusoidal wave pulse high-frequency injection model is used to inject a high-frequency sinusoidal voltage signal into the direct axis direction of the brushless DC motor to stimulate the saturation saliency effect of the motor; The sensorless observer model extracts the response current from the quadrature axis of the brushless DC motor and estimates the speed and position through signal modulation and demodulation, and feeds the estimated rotor angle back into the FOC coordinate transformation.

9. The method for controlling tension of an airborne composite cable according to claim 8, characterized in that: The sensorless observer model applies a second-order generalized integrator and a single-frequency notch filter to the position observation loop, and adopts a position error extraction strategy based on SOGI cascade NOTCH to obtain position error information.

10. The method for controlling the tension of an airborne composite cable according to claim 9, characterized in that: The specific steps of the position error extraction strategy based on SOGI cascade NOTCH are as follows: A high-frequency voltage signal is injected into the direct axis of the brushless DC motor; the high-frequency signal reacts inside the motor to generate a current signal containing position information; The required current signal is extracted through the SOGI filter, and the filtered current signal is demodulated using a multiplier; The demodulated current signal is extracted through the NOTCH filter and used as the input signal of the position estimator; The position error information is output through the position estimator.

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