A Motor Fault Tolerance Control Method for High-Altitude Operation UAVs

Abstract

The present invention provides a motor fault tolerance control method for an unmanned aerial vehicle (UAV) used for high-altitude operations. By collecting the operating state data of the target motor, including vibration signals, temperature signals, current signals, rotational speed signals, attitude information, ambient air pressure, and ambient wind speed, the motor fault type is determined. The fault types include rotor imbalance, current overload, thermal runaway, bearing fault, and single-phase fault. According to the fault type and the current flight state of the UAV, corresponding adjustment operations are performed, including: when there is rotor imbalance, adjusting the PWM duty cycle by calculating the lateral component of the target rotational speed to offset the offset torque, etc. After the adjustment operation is completed, the task execution mode is adjusted according to the motor operating state, including reducing the task load or starting the landing mode, to ensure the completion of the UAV task and flight safety. This method improves the reliability and fault tolerance of the UAV in complex high-altitude operation environments.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and particularly to a motor fault-tolerant control method for an unmanned aerial vehicle (UAV) used for high-altitude operations. Background Art

[0002] With the rapid development of UAV technology, UAVs for high-altitude operations are widely used in fields such as power inspection, agricultural plant protection, and building monitoring. These UAVs usually adopt a multi-rotor structure and an electric drive system, and achieve complex tasks through precise flight control technology and efficient motor drive. In the prior art, the UAV motor control system mostly relies on real-time data acquisition and algorithm-based operating state analysis to ensure flight stability and successful completion of tasks.

[0003] However, in actual operation, UAVs for high-altitude operations face complex and changeable environmental conditions, such as strong winds, high temperatures, and high humidity, which pose higher requirements for the reliability and fault-tolerant ability of motors. The prior art usually performs fault detection and response based on single-sensor data, but there are still limitations in detection accuracy and response efficiency when facing various potential faults such as rotor imbalance, current overload, and thermal runaway. In addition, for mechanical and electrical problems such as bearing faults and open-phase faults, the fault-tolerant ability of the prior art is relatively limited, which may lead to interruption or loss of control of the flight mission.

[0004] Therefore, there is an urgent need to develop a new motor fault-tolerant control method for UAVs used for high-altitude operations. Summary of the Invention

[0005] The present application provides a motor fault-tolerant control method for an unmanned aerial vehicle used for high-altitude operations to improve the reliability and fault-tolerant ability of the UAV in a complex high-altitude operation environment.

[0006] The present application provides a motor fault-tolerant control method for an unmanned aerial vehicle used for high-altitude operations, including:

[0007] Collecting the operating state data of a target motor in the unmanned aerial vehicle used for high-altitude operations, where the operating state data includes vibration signals, temperature signals, current signals, rotational speed signals, attitude information, ambient air pressure, and ambient wind speed;

[0008] Determining the fault type of the target motor according to the operating state data, where the fault type includes rotor imbalance, current overload, thermal runaway, bearing fault, and open-phase fault;

[0009] Execute corresponding adjustment operations according to the fault type and the current flight state of the drone; among them, the adjustment operations include calculating the lateral component of the target rotational speed and adjusting the PWM duty cycle of the motor to counteract the offset torque caused by imbalance when rotor imbalance is detected and the drone is flying at high wind speeds; reducing the power output of the target motor and redistributing the thrust of other motors to maintain flight stability when current overload is detected and the flight altitude of the drone exceeds the set value; switching the target motor to the intermittent operation mode and reducing the internal heat accumulation of the target motor by setting a fixed ratio of shutdown and startup times when thermal runaway is detected and the tilt angle of the drone is greater than the preset threshold; reducing the rotational speed of the target motor and adjusting the thrust output of other motors to reduce the axial load of the target motor when bearing failure is detected and the drone is in a long-term hovering state; reducing the load of the target motor, switching to the emergency power reduction mode, and adjusting the attitude of the drone to balance the overall thrust distribution when phase loss fault is detected and the thrust of the drone is insufficient;

[0010] After the adjustment operation is completed, adjust the task execution method of the drone according to the operating state of the target motor, including reducing the load of high-altitude operation tasks or starting the landing mode until the drone task is completed or safely landed.

[0011] Furthermore, collecting the operating state data of the target motor in the high-altitude operation drone includes:

[0012] Real-time monitor the operating state of the target motor through a vibration sensor, collect vibration signals, and record the amplitude and frequency of the vibration for analyzing the balance state and mechanical operating characteristics of the motor;

[0013] Collect the temperature signals on the surface and surrounding environment of the target motor through a temperature sensor, and compare it with the safe operating temperature range of the motor for evaluating whether there is a risk of thermal runaway in the motor;

[0014] Detect the three-phase current signals of the target motor using a current sensor and record the change trend of the current for identifying current anomalies and possible electrical faults;

[0015] Obtain the real-time rotational speed signal of the target motor through a rotational speed sensor and analyze the stability and change pattern of the rotational speed for evaluating the operating performance and mechanical loss of the motor;

[0016] Combine with the attitude sensor of the drone to collect attitude information, including roll angle, pitch angle and yaw angle, for analyzing the impact of the fault of the target motor on the overall attitude of the drone;

[0017] Measure the environmental air pressure and wind speed in the area where the drone is located using an environmental sensor to evaluate the potential impact of the external environment on the operation of the motor.

[0018] Further, determining the fault type of the target motor according to the operating state data includes:

[0019] Based on the collected operating state data, analyze the vibration signal. When the vibration amplitude exceeds the preset normal operating range and there are irregular periodic changes, it is determined as a rotor imbalance fault;

[0020] Compare the collected current signal with the rated current range of the target motor. When the current value continuously exceeds the set safety threshold and the motor power output does not significantly decrease, it is determined as a current overload fault.

[0021] Further, determining the fault type of the target motor according to the operating state data further includes:

[0022] Real-time monitor the collected temperature signal. When the temperature value of the target motor continuously rises and exceeds the set temperature upper limit, and the influence of the ambient temperature is excluded, it is determined as a thermal runaway fault;

[0023] Comprehensively analyze the speed signal and the vibration signal. When the speed is unstable and accompanied by low-frequency vibration characteristics, and the current signal does not exceed the normal range, it is determined as a bearing fault;

[0024] Combining the current signal and the speed signal, when the current signal shows obvious fluctuations and one of the phase currents tends to zero, and at the same time the motor speed significantly decreases, it is determined as a phase loss fault.

[0025] Further, when detecting current overload and the flight altitude of the drone exceeds the set value, reducing the power output of the target motor and redistributing the thrust of other motors to maintain flight stability includes:

[0026] Real-time monitor the current value of the target motor through a current sensor. When it is detected that the current value of the target motor continuously exceeds the set safety threshold, it is judged as a current overload situation;

[0027] According to the reading of the flight altitude sensor of the drone, confirm whether the current flight altitude of the drone exceeds the set safety altitude value. If the flight altitude meets the ultra-high condition, enter the power reduction adjustment process;

[0028] During the power reduction adjustment process, gradually reduce the power output of the target motor by reducing the PWM duty cycle of the target motor, and limit its power within a safe range to avoid motor overheating or damage;

[0029] Real-time calculate the available thrust of other motors through the flight control system, and evenly distribute the thrust gap caused by the power reduction of the target motor to the remaining motors, especially the adjacent motors, to ensure the overall thrust balance of the drone;

[0030] Combined with the attitude sensor data of the drone, dynamically adjust the thrust output of the remaining motors to control the pitch angle and roll angle of the drone, so that the drone maintains a stable flight state.

[0031] Furthermore, when thermal runaway is detected and the tilt angle of the drone is greater than the preset threshold, switch the target motor to the intermittent operation mode, and reduce the internal heat accumulation of the target motor by setting a fixed ratio of shutdown and startup time, including:

[0032] Real-time monitor the temperature of the target motor through a temperature sensor. When the temperature signal shows that the temperature of the target motor continues to rise and exceeds the set safety threshold, confirm that the target motor has a thermal runaway situation;

[0033] Combined with the attitude sensor data of the drone, detect the pitch angle and roll angle of the drone. When the tilt angle is greater than the preset threshold, trigger the protection mechanism of the target motor;

[0034] Enter the intermittent operation mode, set the operation and shutdown time ratio of the target motor, and ensure that there is enough shutdown time after each operation cycle to reduce the internal heat accumulation of the motor;

[0035] During the intermittent operation mode of the target motor, the flight control system reallocates the thrust of the remaining motors in real time to compensate for the thrust loss during the intermittent shutdown of the target motor, and at the same time adjusts the output power of other motors to keep the attitude of the drone stable;

[0036] Monitor the operating status of other motors to ensure that the reallocated thrust will not cause other motors to be overloaded or overheated, and ensure the safe operation of the entire drone power system;

[0037] The intermittent operation mode continues until the temperature of the target motor returns to the safe range or the drone completes the current task and lands safely. During this process, the drone maintains a stable flight attitude and controllable flight ability.

[0038] Furthermore, when a bearing failure is detected and the drone is in a long-term hovering state, reduce the speed of the target motor and adjust the thrust output of other motors to reduce the axial load of the target motor, including:

[0039] Real-time monitor the operating status of the target motor through a vibration sensor and a speed sensor. When the vibration signal shows abnormal axial vibration and the speed shows irregular fluctuations, determine that the bearing of the target motor has failed;

[0040] Combined with the drone flight control data, confirm that the drone is currently in a long-term hovering state, that is, the height data and attitude data of the flight controller show that the time when the drone remains stationary at a fixed position exceeds the preset threshold;

[0041] Enter the adjustment process, gradually reduce the rotational speed of the target motor, and control it within the lower limit range of the rated speed to relieve the mechanical stress on the bearings, while maintaining sufficient thrust output to avoid the instability of the UAV's attitude;

[0042] Reallocate the thrust of the remaining non-faulty motors through the flight control system, and preferentially increase the thrust of the motor at the diagonal position of the target motor to share the axial load of the target motor;

[0043] Combined with the real-time data of the attitude sensor, dynamically adjust the output thrust of each motor to ensure that the pitch angle and roll angle of the UAV remain within a stable range, so as to maintain the overall balance of the UAV while reducing the load on the target motor.

[0044] The beneficial effects of the technical solution provided by this application include:

[0045] (1) By collecting various operating state data such as vibration signals, temperature signals, current signals, rotational speed signals, attitude information, ambient air pressure, and wind speed, it can comprehensively and real-time reflect the operating state of the motor, so as to accurately identify rotor imbalance, current overload, thermal runaway, bearing failure, and open-phase failure, and improve the accuracy and reliability of fault diagnosis. (2) According to different fault types and the current flight state of the UAV, adopt targeted adjustment operations, such as adjusting the PWM duty cycle, intermittent operation mode, and thrust reallocation, which can quickly relieve the impact of faults and maintain the flight stability and mission continuity of the UAV. (3) Considering the complex working conditions such as strong winds, high loads, and long-term hovering often faced by high-altitude operation UAVs, the method significantly improves the flight reliability of the UAV in harsh environments and reduces the risks of mission interruption and flight out of control through real-time data combined with fault-tolerant control of multiple fault types. (4) After the adjustment operation is completed, dynamically adjust the task execution method according to the operating state of the motor, such as reducing the task load or starting the landing mode, which can ensure the safety of the UAV first while ensuring the completion of the task, and is especially suitable for the emergency response requirements in high-risk operation scenarios. Description of the Drawings

[0046] Figure 1 is a flowchart of a motor fault-tolerant control method for a high-altitude operation UAV provided by the first embodiment of this application. Detailed Embodiments

[0047] Many specific details are set forth in the following description to facilitate a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of this application. Therefore, this application is not limited by the specific embodiments disclosed below.

[0048] The first embodiment of the present application provides a motor fault-tolerant control method for an unmanned aerial vehicle (UAV) used in high-altitude operations. Please refer to Figure 1 which is a schematic diagram of the first embodiment of the present application. The following will describe in detail a motor fault-tolerant control method for an unmanned aerial vehicle (UAV) used in high-altitude operations provided by the first embodiment of the present application in conjunction with Figure 1 this diagram.

[0049] Step S101: Collect the operating state data of the target motor in the unmanned aerial vehicle (UAV) used in high-altitude operations. The operating state data includes vibration signals, temperature signals, current signals, rotational speed signals, attitude information, ambient air pressure, and ambient wind speed.

[0050] In step S101, to collect the operating state data of the target motor in the unmanned aerial vehicle (UAV) used in high-altitude operations, a combination of hardware devices and software algorithms is required to ensure that the acquired data has sufficient accuracy and real-time performance. The operating state data includes vibration signals, temperature signals, current signals, rotational speed signals, attitude information, ambient air pressure, and ambient wind speed. The specific implementation methods are as follows:

[0051] First, to collect vibration signals, highly sensitive vibration sensors can be installed on the housing or fixed bracket of the target motor. The sensor continuously collects the vibration characteristic signals of the motor and transmits them to the controller through a data acquisition system with a sampling frequency of at least 1000 Hz. Vibration signal data is usually in the time domain. For ease of subsequent processing, it can be converted into the frequency domain, and key frequency components can be extracted to reflect the mechanical state of the motor.

[0052] Second, to collect temperature signals, thermocouples or thermistors can be installed in the winding area or on the outer wall of the housing of the motor. The temperature sensor inputs the real-time temperature data into the controller by converting analog signals into digital signals. When collecting temperature data, attention should be paid to the temperature changes in different areas to ensure that local overheating phenomena can be captured.

[0053] To collect current signals, Hall effect current sensors or shunt resistors are required to continuously monitor the current signals of each phase of the target motor and transmit them to the control system. The sensor needs to have high dynamic response characteristics to capture instantaneous current fluctuations. The collected current signals need to be filtered to eliminate high-frequency noise to ensure the accuracy of the signals.

[0054] For the collection of rotational speed signals, optical encoders, Hall sensors, or rotational speed estimation techniques based on back electromotive force can be used. The optical encoder obtains rotational speed data by recording the number of encoding pulses of the rotating shaft, and the Hall sensor calculates the rotational speed based on the change in the internal magnetic field of the motor. The collected data is input into the controller through a high-speed interface and undergoes linear interpolation or smoothing processing.

[0055] The acquisition of attitude information relies on an Inertial Measurement Unit (IMU), which usually integrates a three-axis gyroscope and a three-axis accelerometer. The data collected includes roll angle, pitch angle, yaw angle, and the corresponding angular velocities. Through an attitude calculation algorithm, the real-time attitude parameters of the UAV are calculated and combined with other operating state data for fault judgment.

[0056] The acquisition of ambient air pressure requires the use of a high-precision barometer. The barometer is usually installed in the flight control module of the UAV to obtain the external air pressure value in real time for calculating the relative altitude of the UAV and the change in ambient pressure. The acquisition of ambient wind speed requires a micro wind speed sensor, which is installed at the front or upper part of the UAV to reduce rotor interference. The wind speed magnitude and direction data provided by the wind speed sensor are used to analyze the impact of the external environment on the motor load.

[0057] The output signals of all the above sensors are synchronously sampled through a multi-channel data acquisition card or an embedded controller. The collected operating state data is stored in local memory and aligned according to a unified timestamp to ensure data consistency. For signals with high-frequency noise (such as current and vibration signals), low-pass filters or Fast Fourier Transform (FFT) are required for preprocessing for subsequent fault analysis and control decisions.

[0058] Through the above steps, it is ensured that the collected operating state data of the target motor comprehensively covers possible fault sources and provides a reliable data basis for fault judgment and adjustment operations in subsequent steps.

[0059] Furthermore, the acquisition of the operating state data of the target motor in the high-altitude operation UAV includes:

[0060] The operating state of the target motor is monitored in real time through a vibration sensor, vibration signals are collected, and the amplitude and frequency of the vibration are recorded for analyzing the balance state and mechanical operating characteristics of the motor;

[0061] The temperature signals on the surface and in the surrounding environment of the target motor are collected through a temperature sensor and compared with the safe operating temperature range of the motor to evaluate whether there is a risk of thermal runaway in the motor;

[0062] The three-phase current signals of the target motor are detected using a current sensor, and the change trend of the current is recorded for identifying current anomalies and possible electrical faults;

[0063] The real-time rotational speed signal of the target motor is obtained through a rotational speed sensor, and the stability and change pattern of the rotational speed are analyzed for evaluating the operating performance and mechanical losses of the motor;

[0064] Combined with the attitude sensors of the drone, attitude information is collected, including roll angle, pitch angle, and yaw angle, to analyze the impact of the target motor's failure on the overall attitude of the drone;

[0065] The environmental sensors are used to measure the environmental air pressure and wind speed in the area where the drone is located to evaluate the potential impact of the external environment on the motor operation.

[0066] First, the vibration sensor is used to monitor the vibration condition of the target motor in real time. The vibration sensor is installed on the outer shell or fixed structure of the target motor to capture the vibration signal generated during the motor operation. The amplitude and frequency of the vibration signal are key parameters, and these data are used to analyze the balance state and mechanical operation characteristics of the motor. When the vibration amplitude exceeds the normal operation range or the frequency changes abnormally, it may indicate rotor imbalance or other mechanical failures of the motor.

[0067] Second, the temperature sensors are used to collect the temperature signals on the surface of the target motor and its surrounding environment. These sensors are usually installed at key positions on the motor outer shell to ensure accurate monitoring of the motor operating temperature. The collected temperature signals are compared with the safe operating temperature range of the motor in real time. If the temperature exceeds the upper limit, it may indicate the risk of thermal runaway of the motor. The temperature signals of the surrounding environment are used to exclude the influence of the external environment on the motor temperature, so as to more accurately judge the heat accumulation inside the motor.

[0068] The three-phase current signals of the target motor are detected in real time through current sensors. These sensors are installed in the power supply circuit of the motor and can capture the instantaneous value and change trend of the current. The recorded current data is used to identify possible current anomalies, such as current overload, open-phase fault, or short-circuit condition. When the current signal fluctuates or is unstable in a certain phase, these data provide a direct fault indication.

[0069] The speed sensors are used to obtain the real-time speed signals of the target motor. These sensors are installed at the shaft end or other rotating parts of the motor and can continuously monitor the speed change of the motor. By analyzing the stability and change pattern of the speed signal, the operating performance and mechanical loss of the motor can be evaluated. For example, when the speed shows periodic fluctuations or sudden drops, it may imply bearing failure or abnormal mechanical load.

[0070] The attitude sensors are important components in the operation of the drone and are used to collect the attitude information of the drone, including roll angle, pitch angle, and yaw angle. Combining these data with the operating state of the target motor can analyze the impact of the target motor's failure on the overall attitude of the drone. For example, when the vibration or thrust output of the target motor is abnormal, it may cause the attitude angle of the drone to deviate, thus requiring further adjustment operations.

[0071] In addition, the environmental air pressure and wind speed in the area where the drone is located are measured by environmental sensors, and this data is used to evaluate the potential impact of the external environment on the operation of the motor. Changes in environmental air pressure may affect the cooling effect of the motor, while changes in wind speed may cause the drone to increase the motor load under high wind speed conditions. This data provides important external parameters for analyzing the operating state of the motor.

[0072] Through the above steps, the operating state data of the target motor can be collected comprehensively and accurately. All sensor data is centrally processed by the flight control system of the drone, providing a necessary basis for subsequent fault type judgment and adjustment operations.

[0073] Step S102: Determine the fault type of the target motor according to the operating state data, and the fault types include rotor imbalance, current overload, thermal runaway, bearing fault, and open-phase fault.

[0074] In step S102, according to the operating state data of the target motor collected in step S101, determine the fault type of the target motor. This step needs to accurately judge common motor fault types such as rotor imbalance, current overload, thermal runaway, bearing fault, and open-phase fault through data analysis and comparison with preset thresholds, combined with the operating characteristics of the motor. The specific implementation method is as follows.

[0075] First, for the processing of vibration signals, a frequency domain analysis method needs to be adopted. Through the Fast Fourier Transform (FFT), the collected vibration signals are transformed from the time domain to the frequency domain, and key frequency components are extracted. If the amplitude of a certain frequency significantly exceeds the preset normal operating range, it can be preliminarily judged as rotor imbalance. In addition, by analyzing the change trend of the total amplitude of the vibration signal, the existence of mechanical imbalance problems can be further verified.

[0076] Secondly, the analysis of temperature signals needs to be based on the safe temperature range of the target motor. For the winding temperature, if it exceeds the preset overheat threshold, it is judged as thermal runaway. To further confirm, the temperature change rate can be combined to judge whether the temperature continues to rise rapidly. If the temperature rise trend does not match the operating load, it is further verified whether there is abnormal heat dissipation.

[0077] For the processing of current signals, it is necessary to monitor the changes in the current values of each phase in real time and compare them with the rated current range of the motor. When the current of a certain phase is significantly higher than the safety limit value, it can be judged as a current overload fault. At the same time, if it is detected that the current of a certain phase is continuously zero or intermittent, combined with the voltage signal, it can be judged as an open-phase fault.

[0078] For the analysis of the rotational speed signal, by comparing it with the target rotational speed, it is possible to determine whether there is a deviation. If the change in rotational speed does not conform to the input command and is consistent with the abnormal vibration signal, it can be further verified as rotor imbalance. The abnormal fluctuation of rotational speed data may also indicate other mechanical failures, such as bearing wear.

[0079] The judgment of bearing failure needs to combine the characteristics of vibration signals and rotational speed signals. When the high-frequency component of the vibration signal increases significantly and is accompanied by a decrease in rotational speed, it can be initially determined as a bearing failure. In addition, by continuously monitoring the temperature signal in the bearing area, if the local temperature rises abnormally, it can further confirm the problems of insufficient bearing lubrication or jamming.

[0080] On the basis of combining environmental air pressure and wind speed data, it is also necessary to consider the influence of the external environment on the operating state of the motor. For example, when the wind speed is high and the vibration signal shows periodic fluctuations, it should be analyzed in combination to determine whether it is dynamic imbalance caused by rotor imbalance. The analysis of environmental data can also be used as an auxiliary condition for judging current overload and thermal runaway. For example, the heat dissipation ability decreases under high air pressure or the thrust demand increases in strong winds.

[0081] Through the above data processing and analysis, for different types of faults, the characteristics of signals such as vibration, temperature, current, and rotational speed are extracted in sequence and matched with the preset fault judgment conditions. Finally, the result of fault judgment will be used as the input basis for subsequent adjustment operations to ensure the accuracy and reliability of fault tolerance control.

[0082] Furthermore, determining the fault type of the target motor according to the operating state data includes:

[0083] Based on the collected operating state data, analyze the vibration signal. When the vibration amplitude exceeds the preset normal operating range and there are irregular periodic changes, it is determined as a rotor imbalance fault;

[0084] Compare the collected current signal with the rated current range of the target motor. When the current value continuously exceeds the set safety threshold and the motor power output does not decrease significantly, it is determined as a current overload fault.

[0085] Furthermore, determining the fault type of the target motor according to the operating state data also includes:

[0086] Monitor the collected temperature signal in real time. When the temperature value of the target motor continuously rises and exceeds the set temperature upper limit, and the influence of the environmental temperature is excluded, it is determined as a thermal runaway fault;

[0087] Comprehensively analyze the rotational speed signal and the vibration signal. When the rotational speed is unstable and accompanied by low-frequency vibration characteristics, and the current signal does not exceed the normal range, it is determined as a bearing fault;

[0088] Combining the current signal and the rotational speed signal, when the current signal shows obvious fluctuations and one of the phase currents tends to zero, and at the same time the motor speed drops significantly, it is determined as a single-phase fault.

[0089] When judging the rotor imbalance fault, first analyze the vibration signal collected by the vibration sensor. By comparing the vibration amplitude with the preset normal operating range, it can be preliminarily judged whether there is an abnormality in the motor. If the vibration amplitude exceeds the normal range and is accompanied by irregular periodic changes, this indicates that the rotor may be in an unbalanced state. The imbalance may be caused by mass deviation or installation looseness on the rotor, and such vibration characteristics provide a clear diagnostic basis for rotor imbalance.

[0090] For the current overload fault, the three-phase current signals of the target motor are monitored in real time through the current sensor and compared with the rated current range of the target motor. When the current value continuously exceeds the set safety threshold and the motor power output does not drop significantly, it can be judged as a current overload fault. This situation usually occurs when the load is too large or the circuit is abnormal, and it is necessary to focus on the change trend of the current to avoid motor overheating or damage caused by current overload.

[0091] When determining the thermal runaway fault, the real-time monitoring of the temperature signal is crucial. When the temperature value of the target motor continuously rises and exceeds the set temperature upper limit, the influence of the ambient temperature on the motor needs to be excluded. If the ambient temperature is low and the motor temperature keeps rising, it can be judged as a thermal runaway fault. This fault is usually related to the obstruction of heat dissipation inside the motor or abnormal operation, which may cause permanent damage to the motor, so it is necessary to take measures quickly.

[0092] The judgment of bearing faults requires a comprehensive analysis of the rotational speed signal and the vibration signal. When the rotational speed signal shows instability and is accompanied by low-frequency vibration characteristics, and at the same time the current signal does not exceed the normal range, it can be determined as a bearing fault. This situation indicates that there may be wear, insufficient lubrication or other mechanical problems with the bearing, resulting in abnormal vibration and rotational speed fluctuations during motor operation.

[0093] In the judgment of single-phase faults, it is necessary to analyze by combining the current signal and the rotational speed signal. When the current signal shows obvious fluctuations and one of the phase currents tends to zero, and at the same time the motor speed drops significantly, it can be determined as a single-phase fault. This fault is usually caused by the open circuit or loose connection of one phase of the motor power supply line, which directly affects the stable operation of the motor.

[0094] By describing in detail the judgment methods for the above five types of faults, each judgment method is based on specific sensor data and combined with the actual operating state of the drone for analysis. This comprehensive analysis method ensures the accuracy and real-time nature of fault identification, providing a reliable basis for the motor fault tolerance control of the drone.

[0095] Step S103: Execute corresponding adjustment operations according to the fault type and the current flight state of the drone; among them, the adjustment operations include calculating the lateral component of the target speed when detecting rotor imbalance and the drone is flying at high wind speed, and adjusting the PWM duty cycle of the motor to counteract the offset torque caused by the imbalance; when detecting current overload and the flight altitude of the drone exceeds the set value, reducing the power output of the target motor and redistributing the thrust of other motors to maintain flight stability; when detecting thermal runaway and the tilt angle of the drone is greater than the preset threshold, switching the target motor to the intermittent operation mode and reducing the internal heat accumulation of the target motor by setting a fixed ratio of shutdown and startup time; when detecting bearing failure and the drone is in a long-term hovering state, reducing the speed of the target motor and adjusting the thrust output of other motors to reduce the axial load of the target motor; when detecting phase loss fault and the thrust of the drone is insufficient, reducing the load of the target motor, switching to the emergency power reduction mode, and adjusting the attitude of the drone to balance the overall thrust distribution.

[0096] In step S103, corresponding adjustment operations are executed according to the fault type of the target motor and the current flight state of the drone. The adjustment operations aim to alleviate the impact of the fault on the flight performance by reasonably regulating the operating parameters of the target motor and the overall flight attitude of the drone, and ensure the stable operation of the drone.

[0097] When detecting rotor imbalance and the drone is flying at high wind speed, it is necessary to first calculate the lateral component of the target motor speed to evaluate the offset torque caused by the imbalance. By establishing the dynamic model of the target motor, the influence of the speed change on the asymmetric distribution of the rotor aerodynamic force can be calculated. After obtaining the offset torque, adjust the PWM duty cycle of the target motor to gradually reduce the dynamic imbalance caused by the imbalance, so that the motor output torque is balanced with the thrust of other motors again. This adjustment operation needs to monitor the change of the vibration signal in real time to ensure that the influence of the imbalance is effectively suppressed.

[0098] When detecting current overload and the flight altitude of the drone exceeds the set value, it is necessary to immediately reduce the power output of the target motor. This can be achieved by limiting the input current of the motor while monitoring whether the output power of the motor is lower than the preset safety threshold. While reducing the output of the target motor, it is necessary to recalculate the overall thrust distribution strategy of the drone, appropriately increase the thrust output of other motors to compensate for the power shortage of the target motor, and ensure flight stability and altitude maintenance. The thrust distribution adjustment needs to be dynamically executed according to the real-time attitude data and altitude information in the flight control system.

[0099] When thermal runaway is detected and the tilt angle of the drone is greater than the preset threshold, the target motor should be immediately switched to the intermittent operation mode. This mode controls the operation cycle of the target motor by setting a fixed ratio of shutdown and startup times, thereby reducing its heat accumulation. To ensure that the thermal runaway problem is alleviated, the parameter settings of the intermittent operation mode need to be based on the real-time temperature signal of the target motor and the task load situation. Meanwhile, the flight control system needs to adjust the drone's attitude to avoid flight instability caused by the intermittent operation of the target motor.

[0100] When a bearing fault is detected and the drone is in a long-term hover state, such as when the hover time exceeds a predetermined time, the speed of the target motor should be reduced to reduce the mechanical load on the bearing. At the same time, the thrust output of other motors should be adjusted appropriately to ensure the stable hover attitude of the drone. In the case of a bearing fault, the vibration signal and the speed change of the target motor need to be continuously monitored to evaluate the further wear risk of the bearing. When necessary, the adjustment operation can trigger a change in task priority to reduce the dependence on the target motor.

[0101] When a phase loss fault is detected and the drone has insufficient thrust, the load on the target motor should be reduced and its power output should be limited to avoid further faults caused by phase loss. At the same time, the target motor should be switched to the emergency power reduction mode to reduce the over-dependence on the missing phase. To maintain the flight stability of the drone, the attitude parameters of the drone need to be adjusted through the flight control system, and the thrust output of the remaining motors should be redistributed to balance the overall power distribution. In addition, combining the attitude information and the current flight altitude, the standby landing mode can be activated to ensure the safety of the drone.

[0102] Through the above operations, for different fault types, differential adjustment strategies are adopted, making full use of the operating state data and the regulation ability of the flight control system, so that the fault tolerance control process of the target motor is efficient and implementable.

[0103] The following provides specific examples for each fault type:

[0104] When rotor imbalance is detected and the drone is flying at high wind speeds, it is necessary to adjust the operating state of the target motor to counteract the offset torque caused by the imbalance. The specific operation is to use the vibration signal of the target motor to judge the imbalance direction, and then reduce the PWM duty cycle of the target motor appropriately to reduce its output thrust. For example, if the right motor vibrates too much, causing the drone to deviate to one side, the thrust of this motor can be reduced, and at the same time, the thrust of the adjacent motor can be increased to balance the attitude. After the operation is completed, the flight control system monitors the attitude change of the drone to ensure that the vibration weakens and the flight direction of the drone remains stable.

[0105] When current overload is detected and the flight altitude of the drone exceeds the set value, it is necessary to quickly reduce the power output of the target motor to prevent overheating or further damage. The specific implementation method is to monitor the real-time current value of the motor. When it is found that the current exceeds the set safe current threshold, gradually reduce the PWM duty cycle of the target motor. For example, if the current of the front left motor is overloaded, its power can be reduced to 70% of normal operation, and at the same time, the flight control system distributes more thrust to the remaining motors, especially the rear right motor to balance the attitude of the drone. After adjustment, monitor again whether the current returns to the safe range.

[0106] When thermal runaway is detected and the tilt angle of the drone is greater than the preset threshold, it is necessary to reduce the heat accumulation of the target motor through an intermittent operation mode. The specific implementation is to set the target motor to a fixed start and stop cycle, such as running for 2 seconds and stopping for 1 second. During each operation cycle, reduce the load of the target motor to further reduce heat generation. At the same time, to compensate for the impact of the reduced thrust of the target motor, the other motors will increase their thrust accordingly. For example, when the right motor experiences thermal runaway, gradually increase the thrust of the left motor and the rear motor to maintain the balance of the drone.

[0107] When a bearing fault is detected and the drone is in a long-term hovering state, it is necessary to reduce the rotational speed of the target motor to reduce the mechanical stress on the bearing. The specific operation is to monitor the current rotational speed of the target motor through a rotational speed sensor, and then limit its rotational speed to 70%-80% of the rated speed. At the same time, redistribute the thrust of the remaining motors to maintain the stable hovering of the drone. For example, if the target motor is located in the front right of the drone, after its rotational speed is reduced, the rear left and rear right motors can increase their thrust to balance the load, and the attitude parameters are adjusted in real time through the flight control system to prevent the drone from tilting.

[0108] When a phase loss fault is detected and the thrust of the drone is insufficient, it is necessary to reduce the load of the target motor and switch to the emergency power reduction mode, while adjusting the attitude to balance the overall thrust distribution. The specific operation is to calculate the power reduction ratio according to the remaining working phases of the motor, and then reduce the PWM duty cycle of the target motor to this ratio. For example, when only two phases of a three-phase motor are working, reduce its output power to 2 / 3 of normal operation. At the same time, the thrust of the remaining non-faulty motors is adjusted in real time through the flight control system. For example, increase the thrust of the diagonal motors to compensate for the deficiency of the target motor, ensuring that the flight direction and altitude of the drone remain stable.

[0109] The implementation of each adjustment operation requires real-time analysis of the operation data of the target motor, dynamically adjusting its operation parameters, and redistributing the thrust of other motors through the flight control system, ultimately achieving effective fault tolerance control of the drone.

[0110] Furthermore, when current overload is detected and the flight altitude of the drone exceeds the set value, the power output of the target motor is reduced, and the thrust of other motors is redistributed to maintain stable flight, including:

[0111] The current value of the target motor is monitored in real time through a current sensor. When it is detected that the current value of the target motor continuously exceeds the set safety threshold, it is judged as a current overload situation;

[0112] According to the reading of the flight altitude sensor of the drone, confirm whether the current flight altitude of the drone exceeds the set safety altitude value. If the flight altitude meets the ultra-high condition, enter the power reduction adjustment process;

[0113] During the power reduction adjustment process, the power output of the target motor is gradually reduced by reducing the PWM duty cycle of the target motor, and its power is limited within a safe range to avoid motor overheating or damage;

[0114] The available thrust of other motors is calculated in real time through the flight control system, and the thrust gap caused by the reduction of the target motor power is evenly distributed to the remaining motors, especially the adjacent motors, to ensure the overall thrust balance of the drone;

[0115] Combined with the attitude sensor data of the drone, dynamically adjust the thrust output of the remaining motors, and control the pitch angle and roll angle of the drone to keep the drone in a stable flight state.

[0116] First, the current value of the target motor is monitored in real time through a current sensor installed on the target motor. The current sensor captures the instantaneous current data during motor operation and compares it with a pre-set safe current threshold. If the current value of the target motor continuously exceeds the safe threshold and does not show an obvious downward trend, it is judged as a current overload situation. This overload may be caused by high load, winding overheating or circuit abnormality, and immediate measures need to be taken to prevent motor damage.

[0117] On the basis of confirming current overload, the current altitude data of the drone is obtained through a flight altitude sensor. The flight altitude sensor can measure the flight altitude of the drone through methods such as air pressure, GPS or laser ranging. When the altitude data exceeds the pre-set safe flight altitude value, it indicates that the drone is in a high-altitude flight state. At this time, the risk brought by current overload may intensify. Therefore, the system enters the power reduction adjustment process to protect the target motor and maintain the stable flight of the drone.

[0118] During the power-down adjustment process, the power output of the target motor is gradually reduced by decreasing its PWM duty cycle. The reduction of the PWM duty cycle directly reduces the input power of the motor, thereby limiting its output power within a safe range. The adjustment process needs to be carried out gradually to avoid sudden impacts on the overall thrust balance of the drone. By controlling the power output of the target motor, its current load can be effectively reduced while avoiding overheating or permanent damage to the motor windings due to overload.

[0119] As the power of the target motor decreases, the flight control system needs to calculate in real time the thrust gap generated by the reduced thrust and evenly distribute this thrust gap to other motors, especially those adjacent to the target motor in terms of position. This process is based on the real-time operating data of other motors and the current thrust requirements. The flight control system dynamically adjusts the thrust output of these motors to ensure that the total thrust of the drone can maintain the stability required for flight.

[0120] Meanwhile, the overall flight state is monitored through the attitude sensor data of the drone, including changes in pitch angle, roll angle, and yaw angle. If an attitude deviation is caused during the thrust distribution process, the system will dynamically adjust the output thrust of other motors to balance the attitude of the drone and restore its normal flight state. For example, when the target motor is located at the front right of the drone and its power is reduced, the system can increase the thrust of the motors at the rear left and rear right to keep the pitch angle and roll angle stable.

[0121] Furthermore, when thermal runaway is detected and the tilt angle of the drone is greater than a preset threshold, switch the target motor to the intermittent operation mode, and reduce the internal heat accumulation of the target motor by setting a fixed ratio of shutdown and startup times, including:

[0122] The temperature of the target motor is monitored in real time through a temperature sensor. When the temperature signal shows that the temperature of the target motor continues to rise and exceeds the set safety threshold, it is confirmed that the target motor has a thermal runaway situation;

[0123] Combined with the attitude sensor data of the drone, the pitch angle and roll angle of the drone are detected. When the tilt angle is greater than the preset threshold, the protection mechanism of the target motor is triggered;

[0124] Enter the intermittent operation mode, set the operation and shutdown time ratio of the target motor, and ensure that there is enough shutdown time after each operation cycle to reduce the internal heat accumulation of the motor;

[0125] During the period when the target motor is in the intermittent operation mode, the thrust of the remaining motors is redistributed in real time through the flight control system to compensate for the thrust loss during the intermittent shutdown of the target motor, and at the same time, the output power of other motors is adjusted to keep the attitude of the drone stable;

[0126] Monitor the operating status of other motors to ensure that the reallocated thrust will not cause other motors to be overloaded or overheated, and ensure the safe operation of the entire UAV power system;

[0127] The intermittent operation mode continues until the temperature of the target motor returns to the safe range or the UAV completes the current mission and lands safely. During this process, the UAV maintains a stable flight attitude and controllable flight ability.

[0128] First, the temperature of the target motor is monitored in real time through a temperature sensor. The temperature sensor is usually installed at key parts of the motor, such as near the housing or winding, to capture the temperature changes during operation. When the temperature signal shows that the temperature of the target motor continues to rise and exceeds the preset safety threshold, it can be confirmed that the target motor has a thermal runaway situation. The occurrence of thermal runaway may be caused by continuous high-load operation, insufficient cooling or other internal problems. This situation needs to be dealt with in time to prevent the motor from being damaged or failing.

[0129] Combined with the attitude sensor data of the UAV, the pitch angle and roll angle of the current UAV are detected. When it is detected that the tilt angle of the UAV exceeds the preset safety threshold, it indicates that the attitude of the UAV may have been affected by the abnormal operation of the target motor. In this case, immediately trigger the protection mechanism of the target motor to avoid further heat accumulation and attitude loss of control by adjusting the operation mode.

[0130] After the target motor switches to the intermittent operation mode, the system will operate according to the preset operation and shutdown time ratio. The intermittent operation mode is designed to allow the heat inside the motor to dissipate naturally by setting sufficient shutdown time after each operation cycle, thereby reducing the overall temperature of the motor. This method can not only maintain a certain thrust output but also effectively control the heat accumulation of the motor and prevent its temperature from rising continuously during continuous operation.

[0131] When the target motor enters the intermittent operation mode, the flight control system will reallocate the thrust of other motors in real time to compensate for the thrust loss caused by the shutdown of the target motor. The thrust reallocation needs to be dynamically adjusted according to the current attitude and flight mission of the UAV. Especially for the motor opposite to the position of the target motor, its thrust may need to be increased appropriately to maintain the overall flight balance. In addition, the flight control system will also monitor the operating status of other motors to ensure that the reallocated thrust will not cause non-faulty motors to be overloaded or overheated, thus ensuring the safe operation of the entire UAV power system.

[0132] The intermittent operation mode will continue until the temperature of the target motor returns to the safe range or the drone completes the current mission and lands safely. During this process, the drone needs to maintain a stable flight attitude and be able to dynamically adjust flight parameters according to the actual situation. If the task priority is high and the environmental conditions permit, the system will give priority to completing the task and ensuring a safe landing. If the thermal runaway problem is serious, the system will initiate the landing procedure in advance to protect the target motor and the overall drone.

[0133] Each step in this process requires real-time monitoring and dynamic adjustment to ensure the safety and reliability of the drone in a complex operating environment.

[0134] Furthermore, when a bearing failure is detected and the drone is in a long-term hovering state, reducing the speed of the target motor and adjusting the thrust output of other motors to reduce the axial load of the target motor includes:

[0135] Real-time monitor the operating state of the target motor through vibration sensors and speed sensors. When the vibration signal shows abnormal axial vibration and the speed shows irregular fluctuations, it is determined that the bearing of the target motor has failed;

[0136] Combined with the flight control data of the drone, confirm that the drone is currently in a long-term hovering state, that is, the altitude data and attitude data of the flight controller show that the time the drone remains stationary at a fixed position exceeds the preset threshold;

[0137] Enter the adjustment process, gradually reduce the speed of the target motor, and control it within the lower limit range of the rated speed to reduce the mechanical stress on the bearing, while maintaining sufficient thrust output to avoid the instability of the drone's attitude;

[0138] Reallocate the thrust of the remaining non-faulty motors through the flight control system, and give priority to increasing the thrust of the motors at the diagonal position of the target motor to share the axial load of the target motor;

[0139] Combined with the real-time data of the attitude sensor, dynamically adjust the output thrust of each motor to ensure that the pitch angle and roll angle of the drone remain within a stable range, so as to maintain the overall balance of the drone while reducing the load on the target motor.

[0140] First, the operating state of the target motor is monitored in real time through vibration sensors and speed sensors. The vibration sensor is installed on the motor housing or related components to detect the axial vibration signal of the motor during operation. When the vibration signal shows abnormality and exceeds the normal operating range, and at the same time the speed sensor detects irregular fluctuation characteristics, it can be determined that there is a fault in the bearing of the target motor. This kind of fault is usually caused by bearing wear, insufficient lubrication or abnormal mechanical stress, which may lead to a decrease in the operating efficiency of the motor or more serious mechanical damage.

[0141] After confirming the bearing fault of the target motor, it is determined whether the current flight state is long-term hovering through the flight control data of the UAV. The altitude sensor and attitude sensor of the flight control system can provide the position and attitude information of the UAV in real time. When these data indicate that the UAV has remained hovering at a fixed position for more than a preset safety threshold, it is confirmed that the UAV is in a long-term hovering state. In this case, the bearing load of the target motor may continue to increase, and adjustment measures need to be taken immediately to protect the motor.

[0142] The adjustment process starts with gradually reducing the speed of the target motor. The power output of the target motor is controlled by the flight control system to adjust its speed to the lower limit range of the rated speed. Reducing the speed can effectively reduce the mechanical stress on the bearing, thereby reducing bearing wear. However, while reducing the speed, it is necessary to ensure that the target motor still maintains sufficient thrust output to avoid the UAV's attitude instability due to insufficient thrust.

[0143] To make up for the reduction in the thrust of the target motor, the flight control system redistributes the thrust of the remaining non-faulty motors in real time, giving priority to increasing the thrust output of the motor at the diagonal position to the target motor. This can share the axial load of the target motor and maintain the overall balance of the UAV through a reasonable thrust distribution. For other non-faulty motors, the system will dynamically adjust their thrust output to adapt to the new flight requirements.

[0144] Combined with the real-time data of the attitude sensor, the system monitors and adjusts the pitch angle and roll angle of the UAV. By precisely controlling the thrust distribution of each motor, the attitude of the UAV can be maintained within a safe and stable range. Even during the process of reducing the load of the target motor, the UAV can continue to perform hovering tasks or other flight operations without losing control of its attitude due to uneven thrust distribution.

[0145] The entire adjustment process requires real-time monitoring of the operating states of the target motor and other motors to ensure that the adjusted thrust distribution does not cause overloading of non-faulty motors or instability of the UAV as a whole.

[0146] Furthermore, when it is detected that the rotor is unbalanced and the UAV is flying at high wind speeds, calculating the lateral component of the target speed and adjusting the PWM duty cycle of the motor to counteract the offset torque caused by the imbalance includes:

[0147] Calculating the lateral component of the target motor speed according to Formula 1 below:

[0148] ;

[0149] Where Represents the lateral component of the target motor, in radians per second (rad / s). It represents the contribution to the rotational speed in the lateral direction due to vibration.

[0150] Represents the mass of the

[0151] Represents the angular velocity corresponding to the vibration frequency of the

[0152] For the vibration phase angle of the

[0153] is the roll angle of the drone, in radians (rad). This angle is provided in real-time by the attitude sensor.

[0154] Represents the total number of mass points involved in the vibration analysis, determined by the granularity of the vibration analysis, usually 4 to 12.

[0155] Calculate the additional offset torque caused by rotor imbalance according to Formula 2 below :

[0156] ;

[0157] Where represents the additional offset torque;

[0158] is the environmental wind speed, obtained by sensor measurement;

[0159] is the reference wind speed, determined according to the specifications provided by the drone manufacturer;

[0160] Represents the distance from the

[0161] Calculate the lateral correction torque according to Formula 3 below:

[0162] ;

[0163] Among them, represents the correction torque; is the roll angle of the UAV;

[0164] is the yaw angle of the UAV, which is provided in real time by the attitude sensor.

[0165] Calculate the PWM duty cycle of the target motor through the following formula 4 :

[0166] ;

[0167] Among them, is the equivalent resistance of the target motor, with the unit of ohm. It is provided by the motor design parameters.

[0168] is the motor torque constant, with the unit of newton-meter per ampere (N·m / A), which is determined by the motor characteristics.

[0169] is the battery voltage of the target motor, which is determined by the battery characteristics.

[0170] Through the above calculations, the lateral component, offset torque, and correction torque of the target motor are gradually solved. Finally, the PWM duty cycle of the motor is dynamically adjusted according to the correction torque to ensure that the UAV maintains a stable attitude during high wind speed flight.

[0171] Furthermore, when a phase loss fault is detected and the UAV thrust is insufficient, reduce the load of the target motor, switch to the emergency power reduction mode, and adjust the UAV attitude to balance the overall thrust distribution, including:

[0172] Calculate the power factor of the target motor according to the following formula 5 :

[0173] ;

[0174] Among them, represents the remaining working phases of the current target motor, which is determined by detecting the number of normal working phases in the current signal, generally 1 to 2 (for three-phase motors).

[0175] represents the complete working phases of the target motor, and the design value is 3 (for three-phase motors).

[0176] represents the additional offset torque caused by the phase loss fault; it is calculated from the dynamic characteristics of the motor, and the recommended range is 0 to 50 N·m.

[0177] Represents the maximum allowable torque of the target motor, provided by the motor manufacturer.

[0178] Calculate the PWM duty cycle of the target motor according to the following formula 6:

[0179] ;

[0180] Where, Represents the original PWM duty cycle of the target motor, set by the flight control system according to the mission requirements, and the recommended range is 0 to 100%.

[0181] Represents the adjusted PWM duty cycle;

[0182] Calculate the UAV attitude correction factor according to the following formula 7 :

[0183] ;

[0184] Where, Represents the total thrust requirement of the UAV, calculated by the flight control system according to the current flight conditions and load of the UAV, and the recommended range is 50 to 1000 N.

[0185] Is the current roll angle of the UAV, Is the current pitch angle of the UAV, measured by the attitude sensor.

[0186] Represents the remaining working phases of the current target motor; Represents the complete working phases of the target motor;

[0187] Calculate the adjusted thrust of the target motor according to the following formula 8:

[0188] ;

[0189] Where, Is the adjusted thrust of the target motor;

[0190] Is the original thrust of the target motor, set by the flight control system.

[0191] Is the power factor of the target motor, obtained by calculating through formula 5;

[0192] Calculate the thrust of the remaining motors according to the following formula 9:

[0193] ;

[0194] Where, The thrust of the th non-faulty motor after reallocation;

[0195] The thrust of the th non-faulty motor before adjustment, which is usually determined according to the real-time operation data provided by the flight control system of the drone.

[0196] is the attitude correction factor; is the number of currently available non-faulty motors.

[0197] By evenly distributing the correction factor to the non-faulty motors, the compensation for the thrust gap is achieved while maintaining the overall attitude stability of the drone.

[0198] When a phase loss fault is detected in the target motor and it is confirmed that the drone's thrust is insufficient, a series of adjustment operations need to be implemented through the flight control system to ensure that the drone can continue to fly stably and complete the mission. The following are the specific implementation steps for the adjusted thrust and attitude correction:

[0199] First, after calculating the adjusted thrust of the target motor, the flight control system will convert this adjustment result into the operating parameters of the motor. Specifically, by reducing the PWM duty cycle or input current of the target motor, its load and output thrust are directly reduced. This can limit the operating ability of the target motor within the safe range in its faulty state, preventing further damage to the motor or affecting other components.

[0200] For other non-faulty motors, the flight control system will adjust the output thrust of these motors one by one according to the reallocated thrust requirements. The specific operations include sending new commands to the electronic speed controllers (ESCs) of these motors to increase or decrease their PWM duty cycles, so that their thrust increases or decreases to the new set value. Especially for the motor opposite to the position of the target motor, its thrust usually needs to be appropriately increased to make up for the gap caused by the insufficient thrust of the target motor.

[0201] After completing the thrust adjustment, the flight control system monitors the attitude changes of the drone in real time through attitude sensors (such as accelerometers and gyroscopes), including roll angle, pitch angle, and yaw angle. If the attitude deviates from the safe range, for example, the roll angle of the drone tilts towards the side where the target motor is located, the flight control system will dynamically adjust the thrust of other motors to correct the attitude deviation. For example, when the right side of the drone tilts downward, the thrust of the left motor can be increased while the thrust of the right motor is decreased to make the drone return to the horizontal state.

[0202] The flight control system will also continuously monitor the operating status of all motors to ensure that thrust adjustment will not cause non-faulty motors to be overloaded or their temperatures to rise beyond the safe range. If a non-faulty motor approaches its load limit due to the increased thrust reallocated to it, the flight control system will further optimize the thrust distribution strategy and disperse the excess thrust demand to other non-faulty motors.

[0203] The entire adjustment process is dynamic and integrated with the flight mission and environmental conditions of the UAV. For example, under high wind speed conditions, the motors on the windward side may need to increase thrust additionally, while the thrust of the motors on the leeward side may need to be appropriately reduced to maintain the stability of the UAV. The flight control system continuously optimizes the distribution of motor thrust based on real-time wind speed data and the attitude information of the UAV.

[0204] If it is found during the adjustment process that the status of the target motor continues to deteriorate or the loads of other motors are already approaching their limits, the flight control system will automatically activate the landing mode of the UAV. In the landing mode, the load on the target motor is further reduced, and other motors cooperate to decelerate, smoothly landing the UAV in a safe area.

[0205] Step S104: After the adjustment operation is completed, adjust the task execution mode of the UAV according to the operating status of the target motor, including reducing the load of high-altitude operation tasks or activating the landing mode until the UAV mission is completed or safely landed.

[0206] In step S104, after the adjustment operation is completed, adjust the task execution mode of the UAV according to the operating status of the target motor. The adjustment process needs to comprehensively analyze the real-time operating ability of the target motor and the current task requirements of the UAV to ensure the smooth completion of the flight mission or the safe landing of the UAV.

[0207] First, evaluate the remaining performance parameters of the motor based on the operating status data of the target motor, including information such as rotational speed, current, vibration, temperature, etc. If the rotational speed of the motor can be stably maintained within the task requirements range and both the vibration signal and temperature signal do not exceed the preset safety thresholds, it can be determined that the target motor has recovered to an available state and there is no need to further reduce the task load. However, if it is detected that the performance of the target motor has significantly declined, such as large fluctuations in rotational speed, continuous abnormal current, or high-amplitude characteristics in the vibration signal, the load of the high-altitude operation tasks of the UAV needs to be reduced. This can be achieved by adjusting the flight path of the UAV, reducing the working intensity, or shortening the task time, thereby reducing the working pressure on the target motor and extending its operating life.

[0208] When the operating state of the target motor indicates that it cannot be restored to an acceptable range, such as continuous high temperature, phase loss, or other difficult-to-correct faults, the landing mode should be initiated first. In the landing mode, the flight control system first selects a suitable landing point and path based on the current environmental conditions (including air pressure, wind speed, etc.). To ensure the safety of the landing process, it is necessary to dynamically adjust the thrust distribution of other motors to maintain the attitude stability of the UAV. During the descent, it is necessary to continuously monitor the status data of the target motor to ensure that it does not further exacerbate the instability risk of the UAV. At the same time, according to the real-time flight altitude and UAV attitude, gradually reduce the power output of the target motor to prevent the excess torque generated by the faulty motor from affecting the landing trajectory.

[0209] If the failure of the target motor occurs in the middle or later stage of task completion and the UAV is close to the task target area, the flight control system can adjust the task priority and complete the remaining tasks on the premise of ensuring that the target motor is not overloaded. At this time, it is necessary to appropriately reduce the energy consumption of other non-essential task modules, such as turning off some auxiliary equipment or restricting unnecessary attitude adjustments, so as to concentrate the limited power resources on the main task.

[0210] During the entire adjustment process, the system needs to combine the real-time status data of the target motor with the flight status parameters of the UAV (such as attitude angle, thrust distribution, etc.) to dynamically optimize the task execution strategy. Between the adjustment of the task load during high-altitude operation and the switching of the landing mode, the system needs to make the optimal choice based on the real-time analysis results to ensure that both the task completion requirements are met and the overall safety of the UAV is guaranteed. The implementation of this step can effectively cope with the impact of the failure of the target motor on the UAV task and ensure flight safety and task integrity in extreme situations.

[0211] Furthermore, after the adjustment operation is completed, adjusting the task execution mode of the UAV according to the operating state of the target motor, including reducing the task load during high-altitude operation or initiating the landing mode until the UAV task is completed or safely landed, includes:

[0212] Real-time evaluate the remaining performance of the target motor through its operating state data, including the current power output capacity, rotational speed stability, and temperature change trend, to determine whether the target motor can continue to support the current high-altitude operation task;

[0213] When the evaluation result shows that the remaining performance of the target motor is insufficient to complete the current task, immediately reduce the load of the high-altitude operation task;

[0214] Combined with the flight control data of the UAV, judge whether the current environmental conditions are suitable for continuous flight. If the environmental conditions are unfavorable or the operating state of the target motor further deteriorates, initiate the landing mode;

[0215] When starting the landing mode, the drone's landing path is preferentially planned to the nearest safe area. By adjusting the thrust distribution of other motors, the stable descending attitude of the drone is maintained, and the flight altitude is gradually reduced.

[0216] During the landing process, by real-time monitoring the states of the target motor and other motors, the thrust output and attitude of the drone are dynamically adjusted to ensure the safety and controllability of the landing process.

[0217] First, the remaining performance of the target motor is evaluated in real time through its operating state data. These data include the current power output capacity of the motor, the stability of the rotational speed, and the temperature change trend. The power output capacity is deduced from the actual current, voltage, and motor torque characteristics measured by the flight control system to evaluate whether the target motor can maintain its normal operation. The stability of the rotational speed is monitored through the real-time readings of the rotational speed sensor. If frequent fluctuations or significant drops occur, it indicates that the target motor may have lost the ability to output stably. The temperature change trend is provided by the temperature sensor, and a continuously rising temperature indicates that the motor may be at risk of overheating. Combining these indicators, the flight control system can accurately determine whether the target motor can continue to support the current high-altitude operation task.

[0218] If the evaluation result shows that the remaining performance of the target motor is insufficient to complete the current task, the flight control system will immediately take measures to reduce the load of the high-altitude operation task. For example, for a drone carrying supplies, part of the cargo can be released to reduce the flight load; for a drone continuously performing inspections, the task scope can be reduced to shorten the flight time. This load reduction strategy aims to reduce the working pressure of the target motor and at the same time relieve the compensation burden of other non-faulty motors.

[0219] Combined with the real-time flight control data of the flight control system, it is judged whether the current environmental conditions are suitable for the drone to continue flying. If environmental conditions such as strong winds, low air pressure, or high temperatures have an adverse impact on flight, or the operating state of the target motor deteriorates further, such as a sharp rise in temperature or a significant drop in output power, the flight control system will immediately start the landing mode to ensure the safety of the drone.

[0220] When starting the landing mode, the flight control system will preferentially plan the drone's landing path to the nearest safe area, such as a flat open space or an unmanned operation area. The landing path planning combines the current position, altitude, and obstacle distribution of the drone, and through path optimization algorithms, it ensures the safety of the landing process. During the landing process, the stable attitude of the drone is maintained by adjusting the thrust distribution of non-faulty motors. In particular, the thrust of the target motor will be further reduced to reduce the mechanical load, and the thrust distribution of other motors is dynamically adjusted according to the real-time data of the attitude sensor to ensure that the roll angle and pitch angle of the drone remain within a stable range during the descent.

[0221] As the drone gradually reduces its flight altitude, the flight control system continuously monitors the operating states of the target motor and other motors in real time. If it is found that the operating state of a non-faulty motor is abnormal, such as excessive current or rising temperature, the system will further optimize the thrust distribution to avoid the loss of control of the drone's attitude due to a single motor failure. Through this dynamic adjustment, the drone can maintain a stable flight attitude and a controllable descent speed throughout the landing process.

[0222] Finally, after the drone successfully lands, the flight control system will completely stop the operation of the target motor to protect it from further damage, and at the same time record the fault and operation data for subsequent analysis.

[0223] The second embodiment of the present application provides an electronic device, and the electronic device includes:

[0224] A processor;

[0225] A memory for storing a program, which when read and executed by the processor, executes a motor fault tolerance control method for an unmanned aerial vehicle for high-altitude operations provided in the first embodiment of the present application.

[0226] The third embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it executes a motor fault tolerance control method for an unmanned aerial vehicle for high-altitude operations provided in the first embodiment of the present application.

[0227] Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be subject to the scope defined by the claims of the present application.

Claims

1. A motor fault-tolerant control method for a high-altitude operation UAV, characterized in that: include: Collecting the operating status data of the target motor in the aerial work drone, wherein the operating status data includes vibration signal, temperature signal, current signal, speed signal, attitude information, ambient air pressure and ambient wind speed; Determining a fault type of the target motor according to the operating status data, wherein the fault type includes rotor imbalance, current overload, thermal runaway, bearing fault, and phase loss fault; According to the fault type and the current flight state of the drone, the corresponding adjustment operation is performed; wherein, the adjustment operation includes, when a rotor imbalance is detected and the drone is flying at a high wind speed, calculating the lateral component of the target speed, adjusting the PWM duty cycle of the motor to offset the offset torque caused by the imbalance; when a current overload is detected and the drone's flight altitude exceeds a set value, reducing the power output of the target motor, and redistributing the thrust of other motors to maintain flight stability; when thermal runaway is detected and the drone's tilt angle is greater than a preset threshold, switching the target motor to an intermittent operation mode, and reducing the internal heat accumulation of the target motor by setting a fixed shutdown and startup time ratio; when a bearing fault is detected and the drone is in a long-term hovering state, reducing the speed of the target motor and adjusting the thrust output of other motors to reduce the axial load of the target motor; when a phase loss fault is detected and the drone's thrust is insufficient, reducing the load of the target motor, switching to an emergency power reduction mode, and adjusting the drone's attitude to balance the overall thrust distribution; After the adjustment operation is completed, the mission execution mode of the UAV is adjusted according to the operating state of the target motor, including reducing the high-altitude operation mission load or starting the landing mode, until the UAV mission is completed or lands safely.

2. The motor fault-tolerant control method for a high-altitude working UAV according to claim 1 is characterized in that: The collecting of the operating status data of the target motor in the aerial work drone includes: The vibration sensor monitors the operating status of the target motor in real time, collects vibration signals, and records the amplitude and frequency of the vibration to analyze the balance state and mechanical operating characteristics of the motor; The temperature sensor collects the temperature signals of the target motor surface and the surrounding environment, and compares them with the safe operating temperature range of the motor to assess whether the motor has a risk of thermal runaway; Use current sensors to detect the three-phase current signals of the target motor and record the current change trend to identify current anomalies and possible electrical faults; The real-time speed signal of the target motor is obtained through the speed sensor, and the stability and change pattern of the speed are analyzed to evaluate the operating performance and mechanical loss of the motor; Combined with the attitude sensor of the drone, attitude information is collected, including roll angle, pitch angle and yaw angle, to analyze the impact of the target motor failure on the overall attitude of the drone; Environmental sensors are used to measure the ambient air pressure and wind speed in the area where the drone is located to assess the potential impact of the external environment on motor operation.

3. The motor fault-tolerant control method for a high-altitude working UAV according to claim 1 is characterized in that: Determining the fault type of the target motor according to the operating status data includes: Based on the collected operating status data, the vibration signal is analyzed. When the vibration amplitude exceeds the preset normal operating range and there are irregular periodic changes, it is determined to be a rotor imbalance fault; Based on the comparison between the collected current signal and the rated current range of the target motor, when the current value continues to exceed the set safety threshold and the motor power output fails to drop significantly, it is determined to be a current overload fault.

4. The motor fault-tolerant control method for a high-altitude working UAV according to claim 3 is characterized in that: The step of determining the fault type of the target motor according to the operating status data further includes: The collected temperature signals are monitored in real time. When the temperature value of the target motor continues to rise and exceeds the set temperature upper limit, and the influence of the ambient temperature on it is eliminated, it is determined to be a thermal runaway fault; Comprehensively analyze the speed signal and vibration signal. When the speed is unstable and accompanied by low-frequency vibration characteristics, and the current signal does not exceed the normal range, it is determined to be a bearing fault. Combining the current signal and the speed signal, when the current signal shows obvious fluctuations and one phase current tends to zero, and the motor speed drops significantly, it is determined to be a phase loss fault.

5. The motor fault-tolerant control method for a high-altitude working UAV according to claim 1 is characterized in that: When a current overload is detected and the flight altitude of the drone exceeds a set value, the power output of the target motor is reduced, and the thrust of other motors is redistributed to maintain flight stability, including: The current value of the target motor is monitored in real time by a current sensor. When it is detected that the current value of the target motor continuously exceeds the set safety threshold, it is judged as a current overload condition; According to the reading of the drone's flight altitude sensor, confirm whether the drone's current flight altitude exceeds the set safety altitude value. If the flight altitude meets the over-altitude condition, enter the power reduction adjustment process; During the power reduction adjustment process, the power output of the target motor is gradually reduced by reducing the PWM duty cycle of the target motor, and its power is limited to a safe range to avoid overheating or damage to the motor; The flight control system calculates the available thrust of other motors in real time, and evenly distributes the thrust gap caused by the reduction of the target motor power to the remaining motors to ensure the overall thrust balance of the drone. Combined with the drone's attitude sensor data, the thrust output of the remaining motors is dynamically adjusted to control the drone's pitch and roll angles to keep the drone in a stable flight state.

6. The motor fault-tolerant control method for a high-altitude working UAV according to claim 1 is characterized in that: When thermal runaway is detected and the tilt angle of the drone is greater than a preset threshold, the target motor is switched to an intermittent operation mode, and the internal heat accumulation of the target motor is reduced by setting a fixed stop and start time ratio, including: The temperature of the target motor is monitored in real time by a temperature sensor. When the temperature signal shows that the temperature of the target motor continues to rise and exceeds the set safety threshold, it is confirmed that the target motor is in thermal runaway; Combined with the attitude sensor data of the drone, the pitch and roll angles of the drone are detected. When the tilt angle is greater than the preset threshold, the protection mechanism of the target motor is triggered; Enter intermittent operation mode and set the ratio of running and stopping time of the target motor to ensure that there is enough stopping time after each operation cycle to reduce the heat accumulation inside the motor; When the target motor is in intermittent operation mode, the flight control system redistributes the thrust of the remaining motors in real time to compensate for the thrust loss during the intermittent shutdown of the target motor, and adjusts the output power of other motors to keep the attitude of the drone stable; Monitor the operating status of other motors to ensure that the redistributed thrust does not cause other motors to overload or overheat, thus ensuring the safe operation of the entire UAV power system; The intermittent operation mode continues until the temperature of the target motor returns to a safe range or the drone completes the current mission and lands safely. During this process, the drone maintains a stable flight attitude and controllable flight capability.

7. The motor fault-tolerant control method for a high-altitude working UAV according to claim 1, characterized in that: When a bearing fault is detected and the UAV is in a long-term hovering state, the rotation speed of the target motor is reduced and the thrust output of other motors is adjusted to reduce the axial load of the target motor, including: The operating status of the target motor is monitored in real time through the vibration sensor and the speed sensor. When the vibration signal shows abnormal axial vibration and irregular fluctuations in speed, it is determined that the bearing of the target motor is faulty. Combined with the UAV flight control data, it is confirmed that the UAV is currently in a long-term hovering state, that is, the flight controller's altitude data and attitude data show that the UAV remains motionless at a fixed position for a time exceeding a preset threshold; Enter the adjustment process, gradually reduce the speed of the target motor and control it within the lower limit of the rated speed to reduce the mechanical stress of the bearing, while maintaining sufficient thrust output to avoid the UAV's attitude instability; The flight control system redistributes the thrust of the remaining non-faulty motors, giving priority to increasing the thrust of the motors at the diagonal position of the target motor to share the axial load of the target motor. Combined with the real-time data of the attitude sensor, the output thrust of each motor is dynamically adjusted to ensure that the pitch and roll angles of the drone remain within a stable range, thereby maintaining the overall balance of the drone while reducing the target motor load.

8. The motor fault-tolerant control method for a high-altitude working UAV according to claim 1 is characterized in that: When a rotor imbalance is detected and the UAV is flying at a high wind speed, the lateral component of the target speed is calculated, and the PWM duty cycle of the motor is adjusted to offset the offset torque caused by the imbalance, including: According to the following formula 1, the lateral component of the target motor speed is calculated: ； in, represents the lateral component of the target motor; Indicates The mass of each vibrating mass point; Indicates The angular velocity corresponding to the vibration frequency of each vibrating mass point; For the The vibration phase angle of each vibrating mass point; is the roll angle of the drone; Indicates the total number of mass points involved in vibration analysis; According to the following formula 2, the additional offset torque caused by rotor imbalance is calculated: : ； in, represents the additional offset moment; is the ambient wind speed; is the reference wind speed; Indicates The distance from the vibrating mass point to the rotation axis; The lateral correction moment is calculated according to the following formula 3: ； in, represents the correction torque; is the yaw angle of the drone; The PWM duty cycle of the target motor is calculated by the following formula 4: : ； in, is the equivalent resistance of the target motor; is the motor torque constant; is the battery voltage of the target motor.

9. The motor fault-tolerant control method for a high-altitude working UAV according to claim 1, characterized in that: When a phase failure is detected and the thrust of the drone is insufficient, the load of the target motor is reduced, the emergency power reduction mode is switched, and the attitude of the drone is adjusted to balance the overall thrust distribution, including: According to the following formula 5, calculate the power factor of the target motor : ； in, Indicates the remaining working phases of the current target motor; Indicates the number of complete working phases of the target motor; Indicates the additional offset torque caused by phase failure; Indicates the maximum allowable torque of the target motor; According to the following formula 6, calculate the PWM duty cycle of the target motor: ； in, Indicates the original PWM duty cycle of the target motor; Indicates the adjusted PWM duty cycle; According to the following formula 7, calculate the drone attitude correction factor : ； in, represents the total thrust requirement of the UAV; is the current roll angle of the drone; is the current pitch angle of the drone; Indicates the remaining working phases of the current target motor; Indicates the number of complete working phases of the target motor; The adjusted thrust of the target motor is calculated according to the following formula 8: ； in, is the adjusted target motor thrust; is the original target motor thrust; is the power factor of the target motor; The remaining motor thrust is calculated according to Formula 9 below: ； in, After redistribution Thrust of a non-faulty motor; Before adjustment Thrust of a non-faulty motor; is the attitude correction factor; is the number of non-faulty motors currently available.

10. The motor fault-tolerant control method for a high-altitude working UAV according to claim 1, characterized in that: After the adjustment operation is completed, the task execution mode of the UAV is adjusted according to the operating state of the target motor, including reducing the high-altitude operation task load or starting the landing mode, until the UAV task is completed or landed safely, including: The remaining performance of the target motor is evaluated in real time through its operating status data, including the current power output capacity, speed stability, and temperature change trend, to determine whether the target motor can continue to support the current high-altitude operation task; When the evaluation results show that the remaining performance of the target motor is insufficient to complete the current task, the load of the aerial work task is immediately reduced; Combined with the flight control data of the UAV, it determines whether the current environmental conditions are suitable for continuous flight. If the environmental conditions are unfavorable or the operating status of the target motor deteriorates further, the landing mode is initiated; When the landing mode is activated, the drone's landing path is planned to the nearest safe area first, and the drone's stable descent posture is maintained by adjusting the thrust distribution of other motors, and the flight altitude is gradually reduced; During the landing process, the status of the target motor and other motors is monitored in real time, and the thrust output and attitude of the drone are dynamically adjusted to ensure the safety and controllability of the landing process.

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