Mooring cable control method and device

Abstract

The invention provides a mooring cable control method and device, and the method comprises the steps: determining the expected torque of a take-up and pay-off motor corresponding to a mooring cable based on the actual tension and expected tension of the mooring cable corresponding to a target unmanned plane; based on the expected torque and the actual torque of the take-up and pay-off motor, the expected current of the take-up and pay-off motor is determined; based on the expected current and the actual current of the take-up and pay-off motor, a control signal corresponding to the take-up and pay-off motor is determined; and controlling the take-up and pay-off motor to control the mooring cable based on the control signal. The take-up and pay-off motor is controlled through three closed loops of tension-torque-current, and the tension outer ring can solve the expected torque of the take-up and pay-off motor according to the real-time state of the mooring cable; the torque and current inner ring controls operation of the take-up and pay-off motor in a high-dynamic and high-precision mode, control over constant tension of the mooring cable is achieved, and reliable operation of the mooring unmanned aerial vehicle system is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of aircraft control technology, and in particular to a tethered cable control method and apparatus. Background Technology

[0002] Drones have broad application prospects in emergency rescue, agricultural plant protection, and military fields, but their limited battery life usually makes it difficult to perform long-duration missions. Tethered drones solve this problem by using ground power and continuously supplying power to the aircraft through a tethering cable.

[0003] However, when adjusting the flight altitude, the length of the tether cable needs to be adjusted in a timely manner. If the cable tension is unstable, it may affect the attitude control of the drone, thus posing a hidden danger to the safe and stable operation of the aircraft.

[0004] Existing tethered cable deployment and retrieval systems mostly rely on manual adjustment of the ground-based tether box motor torque, or adjustment based on altitude information transmitted from the flight control unit. These methods suffer from slow dynamic response and poor control precision, making them unsuitable for automated deployment and retrieval under complex conditions such as strong winds or rapid takeoffs and landings of drones. Therefore, an effective solution is urgently needed to address these issues. Summary of the Invention

[0005] To address the above problems, the present invention provides a method and apparatus for controlling tethered cables.

[0006] This invention provides a method for controlling tethered cables, comprising: Based on the actual tension and expected tension of the tether cable corresponding to the target UAV, the expected torque of the take-up and release motor corresponding to the tether cable is determined; Based on the desired torque and the actual torque of the take-up and release motor, the desired current of the take-up and release motor is determined; Based on the desired current and the actual current of the take-up and release motor, determine the control signal corresponding to the take-up and release motor; The take-up and release motor is controlled based on the control signal to control the mooring cable.

[0007] According to a tethered cable control method provided by the present invention, determining the desired torque of the take-up and release motor corresponding to the tethered cable based on the actual tension and desired tension of the tethered cable corresponding to the target UAV includes: Obtain the actual tension and the desired tension of the tethered cable corresponding to the UAV; Calculate the tension error between the actual tension and the desired tension; Based on the tension error, calculate the rate of change of error; The tension error and the rate of change of error are processed using fuzzy control rules to obtain the desired torque of the take-up and unwinding motor.

[0008] According to a tethered cable control method provided by the present invention, the step of using fuzzy control rules to process the tension error and the error change rate to obtain the desired torque of the take-up and release motor includes: The tension error and the rate of change of error are respectively fuzzed to obtain the first membership degree corresponding to the tension error and the second membership degree corresponding to the rate of change of error; Based on the first membership degree, the second membership degree, the pre-built rule base, and the minimum operation reasoning method, fuzzy reasoning is performed on the tension error and the error change rate to obtain the output membership degree; The output membership degree is defuzzified using the centroid method to obtain the desired torque of the take-up and unwind motor.

[0009] According to the present invention, a method for controlling tethered cables includes performing fuzzy inference on the tension error and the rate of change of error based on the first membership degree, the second membership degree, a pre-built rule base, and a minimum computational inference method to obtain the output membership degree, comprising: Based on the first membership degree and the second membership degree, calculate the activation strength of each fuzzy rule in the rule base: A minimization algorithm is used to calculate the output fuzzy set of each fuzzy rule; The maximization algorithm is used to aggregate the output fuzzy sets of all the fuzzy rules to obtain the output membership degree.

[0010] According to a tethered cable control method provided by the present invention, determining the control signal corresponding to the take-up and release motor based on the desired current and the actual current of the take-up and release motor includes: Based on the actual current of the take-up and release motor, predict the current of the take-up and release motor at the next moment; Calculate the current error between the desired current and the predicted current, and determine the inverter switching state that minimizes the current error; The inverter switch state is used as the control signal for the take-up and unwinding motor.

[0011] According to a tethered cable control method provided by the present invention, the predicted current includes a first predicted current value of the stator in the take-up and release motor under the direct axis at the next moment and a second predicted current value of the stator under the quadrature axis at the next moment; the expected current includes the first expected current value of the stator under the direct axis and the second expected current value of the stator under the quadrature axis. The step of predicting the current of the take-up and release motor at the next moment based on the actual current of the take-up and release motor includes: The sampling period, permanent magnet flux linkage, stator resistance, stator winding inductance, actual voltage, permanent magnet flux linkage, and rotational speed of the take-up and release motor at the current moment are obtained. The actual voltage includes the first voltage measurement value of the stator under the direct axis at the current moment and the second voltage measurement value of the stator under the quadrature axis at the current moment. The first predicted current value is predicted based on the actual current, the sampling period, the stator resistance, the rotational speed, the stator winding inductance, and the first voltage measurement value; and the second predicted current value is predicted based on the actual current, the sampling period, the stator resistance, the rotational speed, the stator winding inductance, the second voltage measurement value, and the permanent magnet flux linkage.

[0012] According to the present invention, a tethered cable control method is provided, wherein the actual current includes a first current measurement value of the stator of the take-up and release motor under the direct axis at the current moment and a second current measurement value of the stator under the quadrature axis at the current moment; And / or, the stator winding inductance includes the first winding inductance of the stator under the direct axis and the second winding inductance of the stator under the quadrature axis.

[0013] According to a tethered cable control method provided by the present invention, determining the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor includes: Calculate the torque error between the desired torque and the actual torque; The torque error is processed by proportional-integral-differential (PID) to obtain the desired current of the take-up and unwinding motor.

[0014] According to a tethered cable control method provided by the present invention, before determining the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor, the method further includes: Obtain the three-phase input current of the take-up and release motor; The actual torque of the take-up and unwind motor is calculated based on the three-phase input current.

[0015] The present invention also provides a tethered cable control device, comprising: The tension processing module is configured to determine the desired torque of the take-up and release motor corresponding to the tether cable based on the actual tension and desired tension of the tether cable corresponding to the target UAV. The torque processing module is configured to determine the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor. The current processing module is configured to determine the control signal corresponding to the take-up and release motor based on the desired current and the actual current of the take-up and release motor. The control module is configured to control the take-up and release motor to control the mooring cable based on the control signal.

[0016] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the tethered cable control method as described above.

[0017] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the tethered cable control method as described above.

[0018] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the tethered cable control method as described above.

[0019] The tethered cable control method and apparatus provided by this invention determine the desired torque of the take-up and release motor corresponding to the tethered cable based on the actual tension and desired tension of the tethered cable corresponding to the target UAV; determine the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor; determine the control signal corresponding to the take-up and release motor based on the desired current and the actual current of the take-up and release motor; and control the take-up and release motor to control the tethered cable based on the control signal. This invention controls the take-up and release motor through three closed loops of "tension-torque-current". The tension outer loop can obtain the desired torque of the take-up and release motor according to the real-time state of the tethered cable; the torque and current inner loops control the operation of the take-up and release motor with high dynamics and high precision, realizing constant tension control of the tethered cable and ensuring the reliable operation of the tethered UAV system. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating the tethered cable control method provided by the present invention.

[0022] Figure 2 This is a schematic diagram of the three-closed-loop motor control framework provided by the present invention.

[0023] Figure 3 This is a schematic diagram of the tension error membership function provided by the present invention.

[0024] Figure 4 This is a schematic diagram of the membership function of the error change rate provided by the present invention.

[0025] Figure 5 This is a schematic diagram of the desired torque membership function provided by the present invention.

[0026] Figure 6 This is a schematic diagram of the tethered cable control device provided by the present invention.

[0027] Figure 7 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] The following is combined Figures 1-6 The present invention describes a tethered cable control method and apparatus.

[0030] Figure 1 This is a flowchart illustrating the tethered cable control method provided by the present invention, as shown below. Figure 1 As shown, the method includes steps 101 to 104.

[0031] Step 101: Based on the actual tension and expected tension of the tether cable corresponding to the target UAV, determine the expected torque of the take-up and release motor corresponding to the tether cable.

[0032] Specifically, the target drone refers to the tethered drone whose tether cable needs to be controlled. Actual tension indicates the current tension or pull on the tether cable. Desired tension refers to the tension of the tether cable under ideal conditions. The take-up / release motor is the motor that controls the length of the tether cable, i.e., the motor that tightens or loosens the tether cable. Desired torque refers to the torque of the take-up / release motor under ideal conditions.

[0033] In practical applications, the actual tension and expected tension of the mooring cable can be obtained first, and then the actual tension and expected tension can be processed according to the set torque determination strategy to obtain the expected torque of the take-up and release motor.

[0034] For example, the present invention provides a three-closed-loop motor control framework based on tension-torque-current to achieve high-performance closed-loop control of tether cable tension. See also Figure 2 , Figure 2 This is a schematic diagram of the three-closed-loop motor control framework provided by the present invention: the three-closed-loop motor control framework includes tension closed-loop control, torque closed-loop control and current closed-loop control.

[0035] In this system, the tension closed-loop control takes the desired tension F* and the actual tension F as inputs and the desired torque T* as output. The actual tension F is obtained through a tension acquisition device, which can be a physical sensor such as a three-pulley tension sensor, or a sensorless computing unit; the type of device is not limited.

[0036] Step 102: Determine the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor.

[0037] Specifically, actual torque refers to the torque of the take-up / layout motor under its current state. Desired current refers to the current of the take-up / layout motor under ideal conditions.

[0038] In practical applications, based on the desired torque of the take-up and release motor, the actual torque and desired torque of the take-up and release motor are processed according to the set current determination strategy to obtain the desired current of the take-up and release motor.

[0039] For example, see Figure 2 The torque closed-loop control takes the desired torque T* and the actual torque T as inputs, and the desired current I* of the take-up and lay-out motor as the output. The actual torque T can be obtained by measuring and calculating the parameters of the take-up and lay-out motor.

[0040] Step 103: Based on the desired current and the actual current of the take-up and release motor, determine the control signal corresponding to the take-up and release motor.

[0041] Specifically, the actual current refers to the current of the take-up and release motor in its current state. The control signal refers to the signal used by the take-up and release motor to perform take-up and release operations; the control signal can be a pulse width modulation (PWM) wave.

[0042] In practical applications, based on the desired current of the take-up and release motor, the actual current and desired current of the take-up and release motor are processed according to the set control signal determination strategy to obtain the corresponding control signal for the take-up and release motor.

[0043] For example, see Figure 2The current closed-loop control takes the desired current I* and the actual current I as inputs, and the control signal (such as a PWM wave) corresponding to the take-up and lay-out motor as the output. The actual current I can be obtained by measuring the take-up and lay-out motor using a current sensor. Any type of closed-loop controller can be used as the current controller.

[0044] Step 104: Control the take-up and release motor to control the mooring cable based on the control signal.

[0045] In practical applications, after determining the control signal, see [reference needed]. Figure 2 The take-up and release motor can be controlled based on control signals, so that the take-up and release motor controls the take-up and release of the mooring cable, thereby achieving constant tension of the mooring cable under different take-up and release states.

[0046] The tethered cable control method provided by this invention determines the desired torque of the take-up and release motor corresponding to the tethered cable based on the actual tension and desired tension of the tethered cable corresponding to the target UAV; determines the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor; determines the control signal corresponding to the take-up and release motor based on the desired current and the actual current of the take-up and release motor; and controls the take-up and release motor to control the tethered cable based on the control signal. This invention controls the take-up and release motor through three closed loops: tension, torque, and current. The outer tension loop can obtain the desired torque of the take-up and release motor based on the real-time state of the tethered cable; the inner torque and current loops control the operation of the take-up and release motor with high dynamics and high precision, achieving constant tension control of the tethered cable and ensuring the reliable operation of the tethered UAV system.

[0047] In one or more optional embodiments of the present invention, determining the desired torque of the take-up and release motor corresponding to the tethered cable based on the actual tension and desired tension of the tethered cable corresponding to the target UAV includes: Obtain the actual tension and the desired tension of the tethered cable corresponding to the UAV; Calculate the tension error between the actual tension and the desired tension; Based on the tension error, the desired torque of the take-up and release motor is determined.

[0048] Specifically, tension error refers to the difference between the expected tension and the actual tension.

[0049] In practical applications, the actual tension F of the mooring cable can be obtained using a tension acquisition device, and the pre-set desired tension F* of the mooring cable can also be obtained. The desired tension F* can be obtained through experimental analysis of the mooring cable.

[0050] Furthermore, the difference between the desired tension F* and the actual tension F is calculated to obtain the tension error e. F That is, e F =F*-F. Then, according to the set torque determination strategy, the tension error is processed to obtain the expected torque T* of the take-up and unwinding motor.

[0051] See Figure 2 In tension closed-loop control, the tension error between the desired tension F* and the actual tension F can be calculated. After obtaining the tension error, it is input to the tension controller, which then calculates the desired torque T* of the take-up and release motor.

[0052] The tension controller can be any type of closed-loop controller, such as a traditional proportional-integration-differential controller (PID controller), a fuzzy controller, or a neural network controller. This invention does not limit the type of closed-loop controller.

[0053] In this embodiment of the invention, the tension error between the actual tension and the desired tension is processed by a closed-loop controller, which can improve the accuracy and efficiency of determining the desired torque.

[0054] In one or more optional embodiments of the present invention, determining the desired torque of the take-up and unwinding motor based on the tension error includes: Based on the tension error, calculate the rate of change of error; The tension error and the rate of change of error are processed using fuzzy control rules to obtain the desired torque of the take-up and unwinding motor.

[0055] Specifically, the actual operating states of a tethered drone can be roughly divided into acceleration ascent, deceleration ascent, acceleration descent, deceleration descent, and hovering states. Considering the disturbance of the tethering cable tension by wind in the environment, these states can be summarized as differences in tension error and error change rate in the tension closed-loop control. Because PID control is sensitive to noise, prone to overshoot or steady-state oscillation in dynamic response, and lacks full-condition adaptability of parameters, it is difficult to meet the requirements of tension control with nonlinear, high-disturbance, and highly time-varying characteristics. Therefore, in this embodiment of the invention, fuzzy control is used to determine the desired torque in the tension closed-loop control.

[0056] In practical applications, the tension error can be differentiated to obtain the rate of change of the error. ,Right now Furthermore, according to fuzzy control rules, i.e., using fuzzy control to analyze and process the tension error and error change rate, the desired torque of the take-up and release motor is obtained. This improves the accuracy of the desired torque, thereby enhancing the accuracy of the mooring cable control. The fuzzy inference method used in the fuzzy control rules can be any fuzzy inference method; this invention does not impose any limitations on it.

[0057] For example, the tension controller employs fuzzy control, using tension error as input. The tension controller differentiates the tension error, obtains the tension error, and then processes the tension error and its rate of change based on fuzzy control rules before outputting the desired torque.

[0058] In one or more optional embodiments of the present invention, the step of using fuzzy control rules to process the tension error and the error change rate to obtain the desired torque of the take-up and unwinding motor includes: The tension error and the rate of change of error are respectively fuzzed to obtain the first membership degree corresponding to the tension error and the second membership degree corresponding to the rate of change of error; Based on the first membership degree, the second membership degree, the pre-built rule base, and the minimum operation reasoning method, fuzzy reasoning is performed on the tension error and the error change rate to obtain the output membership degree; The output membership degree is defuzzified using the centroid method to obtain the desired torque of the take-up and unwind motor.

[0059] In practical applications, we first define the variables and the universe of discourse. The variables are tension error and the rate of change of error.

[0060] Then, see Figure 3 , Figure 3 This is a schematic diagram of the tension error membership function provided by the present invention: The tension error e F The data is divided into 7 fuzzy sets: negative large (NB), negative medium (NM), negative small (NS), zero (ZO), positive small (PS), positive medium (PM), and positive large (PB), and a triangular membership function is constructed, where the horizontal axis represents the tension error and the vertical axis represents the membership degree.

[0061] Similarly, see Figure 4 , Figure 4 This is a schematic diagram of the membership function of the error change rate provided by the present invention: The error change rate... Similarly, it is divided into 7 fuzzy sets: negative large (NB), negative medium (NM), negative small (NS), zero (ZO), positive small (PS), positive medium (PM) and positive large (PB), and a triangular membership function is constructed, where the horizontal axis is the error change rate and the vertical axis is the membership degree.

[0062] Similarly, see Figure 5 , Figure 5 This is a schematic diagram of the membership function of the desired torque provided by the present invention; the desired torque T* is also divided into 7 fuzzy sets: negative large (NB), negative medium (NM), negative small (NS), zero (ZO), positive small (PS), positive medium (PM) and positive large (PB), and a triangular membership function is constructed, where the horizontal axis is the desired torque and the vertical axis is the membership degree.

[0063] Based on the established fuzzy sets and membership functions, the calculated tension error can be fuzzified using the tension error membership function and the corresponding fuzzy set to obtain the first membership degree. Similarly, the calculated error change rate can be fuzzified using the error change rate membership function and the corresponding fuzzy set to obtain the second membership degree.

[0064] Since the actual tension of the drone and tethered cable system is equal to the expected tension in steady state (i.e., the tension error is zero), when the drone switches to accelerated ascent, the actual tension of the tethered cable increases and the rate of change of tension is positive. Therefore, e F <0 and At this point, the torque of the take-up and release motor needs to be reduced to quickly decrease the tension of the mooring cable. Furthermore, the cable tension should be reduced even faster as the magnitude of the tension error and its rate of change increases to ensure cable safety. The same principle applies to other operating conditions; the motor torque output should be adjusted according to the magnitude of the tension error and its rate of change. Therefore, a rule base (i.e., fuzzy rules) is constructed based on the combination of tension error and its rate of change, as shown in Table 1.

[0065] Table 1 Based on the established rule base, and using the first membership degree, second membership degree, and rule base, the minimal operation (Mamdani) reasoning method is employed to perform fuzzy reasoning on tension error and error change rate to obtain the output membership degree.

[0066] Furthermore, the centroid method is used to defuzzify the output membership, thereby achieving precise control output of the desired torque for the take-up and unwinding motors. This provides greater accuracy in achieving the desired torque.

[0067] It should be noted that, in order to further improve the accuracy of the desired torque, the tension error and the rate of change of error can be normalized according to a set range before fuzzification. For example, if the set range is [-3, 3], then the tension error and the rate of change of error can be normalized to the range of [-3, 3].

[0068] In one or more optional embodiments of the present invention, the step of performing fuzzy inference on the tension error and the error change rate based on the first membership degree, the second membership degree, a pre-built rule base, and the minimum operational inference method to obtain the output membership degree includes: Based on the first membership degree and the second membership degree, calculate the activation strength of each fuzzy rule in the rule base: A minimization algorithm is used to calculate the output fuzzy set of each fuzzy rule; The maximization algorithm is used to aggregate the output fuzzy sets of all the fuzzy rules to obtain the output membership degree.

[0069] Specifically, the process of using Mamdani for fuzzy reasoning is as follows.

[0070] First, define the i-th fuzzy rule as: if the fuzzy set corresponding to the tension error is A i And the fuzzy set corresponding to the rate of change of tension error is B. i Then the fuzzy set corresponding to the expected torque is C. i .

[0071] Therefore, the activation strength of the i-th fuzzy rule can be calculated using the following formula. .

[0072] in, Is the tension error in fuzzy set A i Membership degree in Is the rate of change of tension error in fuzzy set B i The degree of membership in the system.

[0073] Then, calculate the output fuzzy set for each fuzzy rule according to the following formula.

[0074] Wherein, U is the process quantity for calculating the torque corresponding to the desired torque T*, that is, the desired torque output quantity; Is the desired torque output U in the fuzzy set C i Membership degree in; The truncated membership degree represents the actual contribution of the fuzzy rule.

[0075] It should be noted that A i That is, the tension error e F It is one of the seven fuzzy sets: negative large (NB), negative medium (NM), negative small (NS), zero (ZO), positive small (PS), positive medium (PM), and positive large (PB). i That is, the rate of change of error. It is one of the seven fuzzy sets: negative large (NB), negative medium (NM), negative small (NS), zero (ZO), positive small (PS), positive medium (PM), and positive large (PB). i The desired torque T* is one of the seven fuzzy sets: negative large (NB), negative medium (NM), negative small (NS), zero (ZO), positive small (PS), positive medium (PM), and positive large (PB).

[0076] Next, according to the following formula, the output fuzzy sets of all fuzzy rules, i.e. the truncated membership degrees, are aggregated to obtain the output membership degrees.

[0077] in, The output membership degree is the sum of all fuzzy rules, where n represents the number of fuzzy rules.

[0078] Based on this, the centroid method is used to complete the defuzzification according to the following formula, thereby achieving precise control output of the desired torque of the take-up and unwinding motor.

[0079] Thus, the min operation aggregates the premises, and the max operation combines the rule results. At the same time, the centroid method is used for defuzzification, which can calculate the centroid of the output fuzzy set as the precise control quantity of the expected torque T* of the take-up and unwinding motor, further improving the accuracy of the expected torque.

[0080] In one or more optional embodiments of the present invention, determining the control signal corresponding to the take-up and release motor based on the desired current and the actual current of the take-up and release motor includes: Based on the actual current of the take-up and release motor, predict the current of the take-up and release motor at the next moment; Calculate the current error between the desired current and the predicted current, and determine the inverter switching state that minimizes the current error; The inverter switch state is used as the control signal for the take-up and unwinding motor.

[0081] In practical applications, the actual tension F of the mooring cable can be obtained using a tension acquisition device, and the pre-set desired tension F* of the mooring cable can also be obtained. The desired tension F* can be obtained through experimental analysis of the mooring cable.

[0082] In practical applications, based on the actual current of the take-up and untake-down motor, the current at the next moment can be predicted based on the actual current, thus obtaining the predicted current at the next moment.

[0083] Furthermore, the difference between the desired current and the predicted current is calculated to obtain the current error. Then, the inverter switching state that minimizes the current error is selected as the control information, and the control signal is output to the take-up and release motor to control the motor to adjust the moored cable. This improves the speed of determining the control signal.

[0084] For example, see Figure 2 In current closed-loop control, the desired current I* and the actual current I can be input to the current controller. The current controller determines the predicted current based on the actual current prediction and selects the inverter switching state that minimizes the current error based on the current error between the desired current and the predicted current as the control information.

[0085] In one or more optional embodiments of the present invention, the take-up and release motor is a permanent magnet synchronous motor. Accordingly, the predicted current includes a first predicted current value of the stator in the take-up and release motor under the direct axis at the next moment and a second predicted current value of the stator under the quadrature axis at the next moment; the expected current includes a first expected current value of the stator under the direct axis and a second expected current value of the stator under the quadrature axis. The step of predicting the current of the take-up and release motor at the next moment based on the actual current of the take-up and release motor includes: The sampling period, permanent magnet flux linkage, stator resistance, stator winding inductance, actual voltage, permanent magnet flux linkage, and rotational speed of the take-up and release motor at the current moment are obtained. The actual voltage includes the first voltage measurement value of the stator under the direct axis at the current moment and the second voltage measurement value of the stator under the quadrature axis at the current moment. The first predicted current value is predicted based on the actual current, the sampling period, the stator resistance, the rotational speed, the stator winding inductance, and the first voltage measurement value; and the second predicted current value is predicted based on the actual current, the sampling period, the stator resistance, the rotational speed, the stator winding inductance, the second voltage measurement value, and the permanent magnet flux linkage.

[0086] Specifically, the quadrature axis and the direct axis are a coordinate system established on the motor rotor, rotating synchronously with the rotor; the quadrature axis, also called the q-axis, is the axis perpendicular to the rotor's magnetic poles and controls the magnitude of the force. The direct axis, also called the d-axis, is the axis in the same direction as the rotor's magnetic poles and controls the magnitude of the magnetic field.

[0087] In practical applications, if the current time is set as time k, then the predicted current includes the predicted value of the motor stator current under the dq axis at time k+1, namely the first predicted current value and the second predicted current value; the expected current includes the expected value of the motor stator current under the dq axis, namely the first expected current value and the second expected current value.

[0088] Therefore, we can first obtain the sampling period, permanent magnet flux linkage, stator resistance, stator winding inductance, actual voltage, permanent magnet flux linkage, and current speed (speed at time k) of the take-up and release motor. Then, based on these parameters and the actual current, we can calculate the first and second predicted current values ​​according to a pre-defined algorithm. This improves the reliability and accuracy of the predicted current.

[0089] In one or more optional embodiments of the present invention, the actual current includes a first current measurement value of the stator under the direct axis and a second current measurement value of the stator under the quadrature axis at the current moment in the take-up and release motor; and / or, the stator winding inductance includes the first winding inductance of the stator under the direct axis and the second winding inductance of the stator under the quadrature axis.

[0090] In practical applications, see Figure 2 The electronic control unit can employ Model Predictive Current Control (MPCC). MPCC uses the desired current of the winding and unwinding motor as the control objective with a cost function, selecting the optimal vector output to control each power device within the inverter to achieve variable frequency speed regulation. This method features fast dynamic response, multi-variable collaborative optimization, explicit constraint handling, high robustness, and adaptability, and has broad application prospects.

[0091] Considering that permanent magnet synchronous motors are mostly used for take-up and unwinding motors, the calculation process for MPCC is as follows.

[0092] The predicted current, i.e., the predicted stator current at time k+1 along the dq axis, can be calculated using the following formula: Among them, T s The system sampling period; This is the predicted value of the motor stator current under the d-axis at time k+1, i.e., the first predicted current value; This is the predicted value of the motor stator current under the q-axis at time k+1, i.e., the second predicted current value; The stator current measurement value of the motor under the d-axis at time k is the first current measurement value. The stator current measurement value of the motor under the q axis at time k is the second current measurement value. The stator voltage measurement value of the motor under the d-axis at time k is the first voltage measurement value. The measured value of the stator voltage of the motor under the q-axis at time k is the second voltage measurement value. The permanent magnet flux linkage for the take-up and untake-down motor; R is the rotational speed of the take-up and release motor at time k; s Stator resistance; This is the stator winding inductance under the d-axis, i.e., the first winding inductance; This is the stator winding inductance along the q-axis, i.e., the second winding inductance.

[0093] Based on the working principle of MPCC, the following cost function g is established: in, This represents the component of the current reference value I* on the d-axis, i.e., the first expected current value. This is the component of the current reference value I* on the q-axis, i.e., the second expected current value.

[0094] Furthermore, the inverter switching state output to the motor that minimizes its error can be selected using the cost function g. This ensures constant tension of the mooring cable under different winding and unwinding states, improving the stability and reliability of the mooring cable control.

[0095] In one or more optional embodiments of the present invention, determining the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor includes: Calculate the torque error between the desired torque and the actual torque; The torque error is processed by proportional-integral-differential (PID) to obtain the desired current of the take-up and unwinding motor.

[0096] In practical applications, the actual torque T of the mooring cable can be obtained by measurement. Further, the difference between the desired torque T* and the actual torque T is calculated to obtain the torque error. Then, according to a set torque determination strategy, the torque error is processed to obtain the desired current for the take-up and release motors. The torque determination strategy can employ a PID algorithm, i.e., PID processing is applied to the torque error to obtain the desired current. This ensures both the speed and accuracy of determining the desired current.

[0097] See Figure 2 In torque closed-loop control, the torque error between the desired torque T* and the actual torque T can be calculated. After obtaining the torque error, it is input to the torque controller, which calculates the desired torque T* of the take-up and unwinding motor. The torque controller adopts PID control.

[0098] For example, the torque controller takes the desired torque T* and the actual torque T as inputs to calculate a reference value for the current required by the motor, i.e., the desired current I*. This process uses... Taking control as an example, the reference value of id Set to 0 where, The calculation process for the desired current I*, which is the differential gain of the PID controller, is shown in the following formula: Where k represents the current time as k. This represents the component of the current reference value I* on the d-axis, i.e., the first expected current value. This is the component of the current reference value I* on the q-axis, i.e., the second expected current value. For torque error, The proportional gain of the PID controller. This is the integral gain of the PID controller.

[0099] It should be noted that before determining the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor, it is also necessary to determine the actual torque.

[0100] To reduce control costs without compromising the accuracy of the actual torque, the actual torque T does not require additional sensors. It can be obtained simply by measuring the three-phase input current of the take-up / play-off motor and calculating it according to a pre-defined algorithm. Specifically, the actual torque T can be calculated using the following formula:

[0101] Where, p n This represents the number of pole pairs of the motor. The permanent magnet flux linkage for the wire reeling and unloading motor. The measured value of the stator current of the motor under the d-axis at time k; The measured value of the stator current of the motor under the q-axis at time k. The stator winding inductance is located along the d-axis. The stator winding inductance is shown in the q-axis diagram. The tethered cable control method provided in this invention achieves constant tension in the tethered cable under different winding and unwinding states by precisely controlling the operation of the winding and unwinding motor within the tether box, thereby improving system stability and reliability. Based on a three-loop motor control framework of "tension-torque-current," an outer loop based on fuzzy control is established to meet the requirements of nonlinear, high-disturbance, and highly time-varying tension control in the system, while an inner loop based on model-predictive direct torque control is established to efficiently control the motor torque, ultimately effectively maintaining constant tension in the tethered cable. Using the tethered cable control method provided in this invention, the tension of the tethered cable can be adaptively controlled to remain constant under different winding and unwinding states, thereby ensuring the safe and stable operation of the tethered UAV's power supply and wired communication, reducing interference from the tethered cable to the UAV's flight control, and improving system operational efficiency.

[0102] In addition, the actual torque of the receiver can be obtained by measuring with relevant sensors, or by calculating the actual torque of the receiver using information such as power and speed, or by any other feasible method. This invention does not limit the actual torque of the receiver in any way.

[0103] The tethered cable control device provided by the present invention is described below. The tethered cable control device described below can be referred to in correspondence with the tethered cable control method described above.

[0104] Figure 6 This is a schematic diagram of the tethered cable control device provided by the present invention, as shown below. Figure 6 As shown, the device includes: The tension processing module 601 is configured to determine the desired torque of the take-up and release motor corresponding to the tether cable based on the actual tension and desired tension of the tether cable corresponding to the target UAV. The torque processing module 602 is configured to determine the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor. The current processing module 603 is configured to determine the control signal corresponding to the take-up and release motor based on the desired current and the actual current of the take-up and release motor. The control module 602 is configured to control the take-up and release motor to control the mooring cable based on the control signal.

[0105] The tethered cable control device provided by this invention includes a tension processing module configured to determine the desired torque of the take-up and release motor corresponding to the tethered cable based on the actual and desired tension of the tethered cable for the target UAV; a torque processing module configured to determine the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor; a current processing module configured to determine the control signal corresponding to the take-up and release motor based on the desired current and the actual current of the take-up and release motor; and a control module configured to control the take-up and release motor to control the tethered cable based on the control signal. This invention controls the take-up and release motor through three closed loops: tension, torque, and current. The outer tension loop calculates the desired torque of the take-up and release motor based on the real-time state of the tethered cable; the inner torque and current loops control the operation of the take-up and release motor with high dynamics and high precision, achieving constant tension control of the tethered cable and ensuring the reliable operation of the tethered UAV system.

[0106] In one or more optional embodiments of the present invention, the tension processing module 601 is specifically configured as follows: Obtain the actual tension and the desired tension of the tethered cable corresponding to the UAV; Calculate the tension error between the actual tension and the desired tension; Based on the tension error, calculate the rate of change of error; The tension error and the rate of change of error are processed using fuzzy control rules to obtain the desired torque of the take-up and unwinding motor.

[0107] In one or more optional embodiments of the present invention, the tension processing module 601 is specifically configured as follows: The tension error and the rate of change of error are respectively fuzzed to obtain the first membership degree corresponding to the tension error and the second membership degree corresponding to the rate of change of error; Based on the first membership degree, the second membership degree, the pre-built rule base, and the minimum operation reasoning method, fuzzy reasoning is performed on the tension error and the error change rate to obtain the output membership degree; The output membership degree is defuzzified using the centroid method to obtain the desired torque of the take-up and unwind motor.

[0108] In one or more optional embodiments of the present invention, the tension processing module 601 is specifically configured as follows: Based on the first membership degree and the second membership degree, calculate the activation strength of each fuzzy rule in the rule base: A minimization algorithm is used to calculate the output fuzzy set of each fuzzy rule; The maximization algorithm is used to aggregate the output fuzzy sets of all the fuzzy rules to obtain the output membership degree.

[0109] In one or more optional embodiments of the present invention, the current processing module 603 is specifically configured as follows: Based on the actual current of the take-up and release motor, predict the current of the take-up and release motor at the next moment; Calculate the current error between the desired current and the predicted current, and determine the inverter switching state that minimizes the current error; The inverter switch state is used as the control signal for the take-up and unwinding motor.

[0110] In one or more optional embodiments of the present invention, the predicted current includes a first predicted current value of the stator in the take-up and unwinding motor under the direct axis at the next moment and a second predicted current value of the stator under the quadrature axis at the next moment; the expected current includes a first expected current value of the stator under the direct axis and a second expected current value of the stator under the quadrature axis. The current processing module 603 is specifically configured as follows: The sampling period, permanent magnet flux linkage, stator resistance, stator winding inductance, actual voltage, permanent magnet flux linkage, and rotational speed of the take-up and release motor at the current moment are obtained. The actual voltage includes the first voltage measurement value of the stator under the direct axis at the current moment and the second voltage measurement value of the stator under the quadrature axis at the current moment. The first predicted current value is predicted based on the actual current, the sampling period, the stator resistance, the rotational speed, the stator winding inductance, and the first voltage measurement value; and the second predicted current value is predicted based on the actual current, the sampling period, the stator resistance, the rotational speed, the stator winding inductance, the second voltage measurement value, and the permanent magnet flux linkage.

[0111] In one or more optional embodiments of the present invention, the actual current includes a first current measurement value of the stator in the take-up and unwinding motor under the direct axis at the current moment and a second current measurement value of the stator under the quadrature axis at the current moment; And / or, the stator winding inductance includes the first winding inductance of the stator under the direct axis and the second winding inductance of the stator under the quadrature axis.

[0112] In one or more optional embodiments of the present invention, the torque processing module 602 is specifically configured as follows: Calculate the torque error between the desired torque and the actual torque; The torque error is processed by proportional-integral-differential (PID) to obtain the desired current of the take-up and unwinding motor.

[0113] In one or more optional embodiments of the present invention, the torque processing module 602 is specifically configured as follows: Obtain the three-phase input current of the take-up and release motor; The actual torque of the take-up and unwind motor is calculated based on the three-phase input current.

[0114] Figure 7 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 7As shown, the electronic device may include a processor 710, a communications interface 720, a memory 730, and a communication bus 740, wherein the processor 710, communications interface 720, and memory 730 communicate with each other via the communication bus 740. The processor 710 can call logic instructions in the memory 730 to execute a tethered cable control method. This method includes: determining the desired torque of the take-up / release motor corresponding to the tethered cable based on the actual tension and desired tension of the tethered cable corresponding to the target UAV; determining the desired current of the take-up / release motor based on the desired torque and the actual torque of the take-up / release motor; determining a control signal corresponding to the take-up / release motor based on the desired current and the actual current of the take-up / release motor; and controlling the take-up / release motor to control the tethered cable based on the control signal.

[0115] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0116] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the tethered cable control method provided by the above methods. The method includes: determining the desired torque of the take-up and release motor corresponding to the tethered cable based on the actual tension and desired tension of the tethered cable corresponding to the target UAV; determining the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor; determining the control signal corresponding to the take-up and release motor based on the desired current and the actual current of the take-up and release motor; and controlling the take-up and release motor to control the tethered cable based on the control signal.

[0117] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the tethered cable control method provided by the above methods. The method includes: determining the desired torque of a take-up / release motor corresponding to the tethered cable based on the actual tension and desired tension of the tethered cable corresponding to the target UAV; determining the desired current of the take-up / release motor based on the desired torque and the actual torque of the take-up / release motor; determining a control signal corresponding to the take-up / release motor based on the desired current and the actual current of the take-up / release motor; and controlling the take-up / release motor to control the tethered cable based on the control signal.

[0118] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0119] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling a mooring cable, characterized in that, include: Based on the actual tension and expected tension of the tether cable corresponding to the target UAV, the expected torque of the take-up and release motor corresponding to the tether cable is determined; Based on the desired torque and the actual torque of the take-up and release motor, the desired current of the take-up and release motor is determined; Based on the desired current and the actual current of the take-up and release motor, determine the control signal corresponding to the take-up and release motor; The take-up and release motor is controlled based on the control signal to control the mooring cable.

2. The tethered cable control method according to claim 1, characterized in that, The determination of the desired torque of the take-up and release motor corresponding to the tethered cable based on the actual tension and desired tension of the tethered cable corresponding to the target UAV includes: Obtain the actual tension and the desired tension of the tethered cable corresponding to the UAV; Calculate the tension error between the actual tension and the desired tension; Based on the tension error, calculate the rate of change of error; The tension error and the rate of change of error are processed using fuzzy control rules to obtain the desired torque of the take-up and unwinding motor.

3. The tethered cable control method according to claim 2, characterized in that, The step of using fuzzy control rules to process the tension error and the rate of change of error to obtain the desired torque of the take-up and unwinding motor includes: The tension error and the rate of change of error are respectively fuzzed to obtain the first membership degree corresponding to the tension error and the second membership degree corresponding to the rate of change of error; Based on the first membership degree, the second membership degree, the pre-built rule base, and the minimum operation reasoning method, fuzzy reasoning is performed on the tension error and the error change rate to obtain the output membership degree; The output membership degree is defuzzified using the centroid method to obtain the desired torque of the take-up and unwind motor.

4. The tethered cable control method according to claim 3, characterized in that, The step of performing fuzzy inference on the tension error and the rate of change of error based on the first membership degree, the second membership degree, a pre-built rule base, and the minimum operational inference method to obtain the output membership degree includes: Based on the first membership degree and the second membership degree, calculate the activation strength of each fuzzy rule in the rule base: A minimization algorithm is used to calculate the output fuzzy set of each fuzzy rule; The maximization algorithm is used to aggregate the output fuzzy sets of all the fuzzy rules to obtain the output membership degree.

5. The tethered cable control method according to claim 1, characterized in that, The step of determining the control signal corresponding to the take-up and release motor based on the expected current and the actual current of the take-up and release motor includes: Based on the actual current of the take-up and release motor, predict the current of the take-up and release motor at the next moment; Calculate the current error between the desired current and the predicted current, and determine the inverter switching state that minimizes the current error; The inverter switch state is used as the control signal for the take-up and unwinding motor.

6. The tethered cable control method according to claim 5, characterized in that, The predicted current includes the first predicted current value of the stator in the take-up and release motor under the direct axis at the next moment and the second predicted current value of the stator under the quadrature axis at the next moment; the expected current includes the first expected current value of the stator under the direct axis and the second expected current value of the stator under the quadrature axis. The step of predicting the current of the take-up and release motor at the next moment based on the actual current of the take-up and release motor includes: The sampling period, permanent magnet flux linkage, stator resistance, stator winding inductance, actual voltage, permanent magnet flux linkage, and rotational speed of the take-up and release motor at the current moment are obtained. The actual voltage includes the first voltage measurement value of the stator under the direct axis at the current moment and the second voltage measurement value of the stator under the quadrature axis at the current moment. The first predicted current value is predicted based on the actual current, the sampling period, the stator resistance, the rotational speed, the stator winding inductance, and the first voltage measurement value; and the second predicted current value is predicted based on the actual current, the sampling period, the stator resistance, the rotational speed, the stator winding inductance, the second voltage measurement value, and the permanent magnet flux linkage.

7. The tethered cable control method according to claim 6, characterized in that, The actual current includes the first current measurement value of the stator under the direct axis of the take-up and release motor at the current moment and the second current measurement value of the stator under the quadrature axis at the current moment; And / or, the stator winding inductance includes the first winding inductance of the stator under the direct axis and the second winding inductance of the stator under the quadrature axis.

8. The tethered cable control method according to claim 1, characterized in that, Determining the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor includes: Calculate the torque error between the desired torque and the actual torque; The torque error is processed by proportional-integral-differential (PID) to obtain the desired current of the take-up and unwinding motor.

9. The method for controlling tethered cables according to any one of claims 1-4, characterized in that, Before determining the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor, the method further includes: Obtain the three-phase input current of the take-up and release motor; The actual torque of the take-up and unwind motor is calculated based on the three-phase input current.

10. A tethered cable control device, characterized in that, include: The tension processing module is configured to determine the desired torque of the take-up and release motor corresponding to the tether cable based on the actual tension and desired tension of the tether cable corresponding to the target UAV. The torque processing module is configured to determine the desired current of the take-up and release motor based on the desired torque and the actual torque of the take-up and release motor. The current processing module is configured to determine the control signal corresponding to the take-up and release motor based on the desired current and the actual current of the take-up and release motor. The control module is configured to control the take-up and release motor to control the mooring cable based on the control signal.

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