Motor noise suppression control method

Abstract

The invention discloses a motor noise suppression control method, and relates to the field of electronic speed controllers of multi-rotor unmanned aerial vehicles. According to the motor noise suppression control method, no-load operation is carried out on a motor, the rotating speed of the motor is gradually increased from 0 to the highest rotating speed through a motor controller, in the speed increasing process of the motor, the noise performance of the whole process of the motor is recorded through a decibel meter, and then the rotating speed of the maximum range section of noise is intercepted; a noise point rotating speed is marked as a noise section rotating speed of the motor, then the noise point rotating speed is set as an adjusting electric signal, a noise point avoiding algorithm is designed in a motor controller, the motor automatically adjusts the rotating speed and avoids the noise point rotating speed through the algorithm, and the active noise reduction effect is achieved by reducing the time of the motor at the noise section rotating speed.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-rotor unmanned aerial vehicle (UAV) electronic regulation control, and in particular to a motor noise suppression control method. Background Art

[0002] There are many types of drones on the market, including rotary-wing, fixed-wing and jet types. Rotary-wing drones have relatively higher stability and controllability, so their application areas are wider. They mainly rely on multiple motors to drive the rotors to rotate, thereby providing the entire fuselage with a lift force greater than the fuselage's gravity, allowing the fuselage to perform vertical lift and flight.

[0003] When multiple rotors are in use, some noise is inevitable due to the high-speed rotation of the motors. The noise sources mainly include mechanical noise, electromagnetic noise, and air noise. The first two are fixed parameters, while air noise behaves differently in different external air environments. Therefore, during the noise suppression process, the first two are usually processed.

[0004] Among existing technical solutions, one approach is to optimize the motor body to increase the precision of the overall mechanical assembly and reduce mechanical noise. However, this approach is costly and may also generate noise at other speeds. Another approach is to extract harmonic currents and control them to zero, which can effectively eliminate electromagnetic noise caused by current harmonics. However, the overall effect is not significant.

[0005] After research, it was found that the noise performance of the motor is different at different speeds. Within a certain speed range, the noise of the motor is at its maximum. Therefore, as long as the motor is reasonably kept away from the corresponding noise section speed, the noise reduction effect of the entire drone can be achieved. For this purpose, a motor noise suppression control method is specially provided. Summary of the Invention

[0006] In response to the shortcomings of the existing technology, the present invention provides a motor noise suppression control method, which solves the problem that the current solutions on the market for suppressing motor noise reduce mechanical noise by optimizing the motor body, but the actual cost is high; and eliminates the electromagnetic noise caused by current harmonics by controlling the current harmonics to 0, but the overall effect is not obvious.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: A motor noise suppression control method includes the following steps:

[0008] Step 1: Extract the speed point with the loudest noise during the operation of the motor;

[0009] Step 2: Set the speed of the noise point to adjust the electrical signal;

[0010] Step 4: Design a noise point avoidance algorithm in the motor controller. The motor automatically adjusts its speed through this algorithm to avoid the noise point speed. By reducing the time the motor is in the noise range speed, the active noise reduction effect is achieved.

[0011] Preferably, in step 1, when extracting the speed point with the largest noise during the operation of the motor, the following steps are performed:

[0012] S1. Place the target motor and the decibel meter in the test space and monitor the target motor speed using a tachometer.

[0013] S2. Run the target motor at no load, gradually accelerating the motor speed from zero to the rated speed, and obtain the noise curve of the entire process using a decibel meter;

[0014] S3. Fitting the noise curve with the speed curve to obtain a target noise segment speed. The target noise segment speed obtained at this time is the speed segment with the maximum noise of the motor.

[0015] Preferably, in step 2, the input throttle signal is converted into an electronically controlled target speed signal, so that when the motor reaches the target speed, a control signal is sent to the motor controller. At this time, the motor speed is actively changed by the motor controller, so that the motor speed quickly leaves the noise section speed range.

[0016] Preferably, the sources of noise during the operation of the motor include:

[0017] Mechanical noise is generated by the collision and friction between internal parts during rotation. Without considering wear and aging, the mechanical noise at a fixed speed is a fixed value and can be measured by a decibel meter.

[0018] Electromagnetic noise is caused by the interaction of the magnetic fields between the stator and rotor inside the motor, which causes the motor core to vibrate, thereby generating noise. Mechanical noise at a fixed speed has a fixed value and can be measured with a decibel meter.

[0019] Air noise is caused by the friction of airflow and vibration of the working parts when the motor's actual working parts come into contact with the air. In addition to being affected by the motor speed, it is also related to the external airflow velocity and is a variable noise.

[0020] Preferably, when extracting the rotation speed of the motor noise point, air noise is ignored, and the combined noise effect of mechanical noise and electromagnetic noise is actually detected.

[0021] Preferably, the algorithm logic for avoiding noise points is as follows:

[0022] 1. Extract the speed of the noise points in the noise segment, and mark the speed as V1, V2, ..., Vn;

[0023] 2. Get the current motor speed, marked as Va, and get the speed Vb of the previous measurement stage;

[0024] 3. Compare the current speed. If Va-Vb=0, it means that the motor speed is constant. At this time, the motor is in normal operation. At this time, the principle for quickly identifying and judging the current motor speed Va is based on the convergence principle.

[0025] When Va-Vb≠0, it means that the motor speed is in a rapidly changing state. At this time, it is judged that the motor is in the speed adjustment stage. At this time, the principle of quickly identifying and judging the current motor speed Va is based on the acceleration principle.

[0026] Preferably, when the motor is at a constant speed, the current motor speed Va is compared with the interval value. If Va∈{V1, Vn}, the noise reduction system actively intervenes; if Then the noise reduction system does not intervene;

[0027] When the noise reduction system intervenes, it quickly identifies and determines the current motor speed Va, and then quickly adjusts it based on the determination result, so that the motor speed can leave the noise range speed in the fastest time.

[0028] Preferably, the approach principle is: when Va∈{V1, Vn}, if Va-V1≥Vn-V1, then Va is controlled to quickly increase to a state greater than Vn; if Va-V1<Vn-V1, then Va is controlled to quickly decrease to a state less than V1, so that the motor can actively avoid the noise section speed when it is in normal operating state.

[0029] Preferably, the acceleration principle is: if the motor speed is in the adjustment state, the motor has an acceleration a=(Vt-Vo) / t, where Vt is the terminal target speed, Vo is the initial speed before acceleration, and t is the acceleration time. When the motor acceleration a≥0, Va is controlled to quickly increase to a state greater than Vn; when the motor acceleration a<0, Va is controlled to quickly decrease to a state less than V1, so that the motor can actively increase the speed in the noise section during the speed adjustment stage to quickly leave the noise section speed.

[0030] The present invention discloses a motor noise suppression control method, which has the following beneficial effects:

[0031] 1. The motor noise suppression control method operates the motor at no-load and gradually increases the motor speed from 0 to the maximum speed through the motor controller. During the motor speed-up process, the noise performance of the motor is recorded through a decibel meter. The speed of the maximum noise range is intercepted and marked as the noise segment speed of the motor. The noise point speed is set as the adjustment electrical signal. The motor controller is designed with an algorithm to avoid noise points. The motor automatically adjusts the speed through the algorithm to avoid the noise point speed. By reducing the time the motor is at the noise segment speed, the active noise reduction effect is achieved.

[0032] 2. The motor noise suppression control method is designed according to actual applications in the noise point avoidance algorithm and is divided into two cases. When the motor is at a constant speed, the current motor speed will be compared with the minimum and maximum speeds of the noise segment according to the convergence principle, and then the motor speed will be automatically adjusted to the nearest speed value, so as to escape the noise segment speed as quickly as possible; when the motor is in a variable speed state, according to the acceleration principle, when the motor is accelerating, the speed is increased to quickly exceed the maximum speed value of the noise segment. When the motor is decelerating, the speed is reduced to quickly reduce the minimum speed value of the noise segment, so as to reasonably adjust the speed according to the current operating state of the drone, so that the actual operating speed can escape from the noise segment speed while meeting the operating requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a flow chart of the noise suppression control method of the present invention;

[0035] Figure 2 This is a diagram analyzing the noise sources of the motor of the present invention;

[0036] Figure 3 This is a diagram showing the relationship between noise and motor speed in the present invention;

[0037] Figure 4 This is a logical architecture diagram of the noise point avoidance algorithm of the present invention. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0039] The embodiments of the present application provide a motor noise suppression control method to solve the problem that the current solutions on the market for suppressing motor noise reduce mechanical noise by optimizing the motor body, but the actual cost is high; and eliminate the electromagnetic noise caused by current harmonics by controlling the current harmonics to 0, but the overall effect is not obvious.

[0040] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0041] An embodiment of the present invention discloses a motor noise suppression control method.

[0042] According to the attached Figure 1-4 As shown, the following steps are included:

[0043] Step 1: Extract the speed point with the loudest noise during the operation of the motor;

[0044] Step 2: Set the speed of the noise point to adjust the electrical signal;

[0045] Step 4: Design a noise point avoidance algorithm in the motor controller. The motor automatically adjusts its speed through this algorithm to avoid the noise point speed. By reducing the time the motor is in the noise range speed, the active noise reduction effect is achieved.

[0046] Preferably, in step 1, when extracting the speed point with the largest noise during the operation of the motor, the following steps are performed:

[0047] S1. Place the target motor and the decibel meter in the test space and monitor the target motor speed using a tachometer.

[0048] S2. Run the target motor at no load, gradually accelerating the motor speed from zero to the rated speed, and obtain the noise curve of the entire process using a decibel meter;

[0049] S3. Fitting the noise curve with the speed curve to obtain a target noise segment speed. The target noise segment speed obtained at this time is the speed segment with the maximum noise of the motor.

[0050] Preferably, in step 2, the input throttle signal is converted into an electronically controlled target speed signal, so that when the motor reaches the target speed, a control signal is sent to the motor controller. At this time, the motor speed is actively changed by the motor controller, so that the motor speed quickly leaves the noise section speed range.

[0051] Preferably, the sources of noise during the operation of the motor include:

[0052] Mechanical noise is generated by the collision and friction between internal parts during rotation. Without considering wear and aging, the mechanical noise at a fixed speed is a fixed value and can be measured by a decibel meter.

[0053] Electromagnetic noise is caused by the interaction of the magnetic fields between the stator and rotor inside the motor, which causes the motor core to vibrate, thereby generating noise. Mechanical noise at a fixed speed has a fixed value and can be measured with a decibel meter.

[0054] Air noise is caused by the friction of airflow and vibration of the working parts when the motor's actual working parts come into contact with the air. In addition to being affected by the motor speed, it is also related to the external airflow velocity and is a variable noise.

[0055] Preferably, when extracting the rotation speed of the motor noise point, air noise is ignored, and the combined noise effect of mechanical noise and electromagnetic noise is actually detected.

[0056] Preferably, the algorithm logic for avoiding noise points is as follows:

[0057] 1. Extract the speed of the noise points in the noise segment, and mark the speed as V1, V2, ..., Vn;

[0058] 2. Get the current motor speed, marked as Va, and get the speed Vb of the previous measurement stage;

[0059] 3. Compare the current speed. If Va-Vb=0, it means that the motor speed is constant. At this time, the motor is in normal operation. At this time, the principle for quickly identifying and judging the current motor speed Va is based on the convergence principle.

[0060] When Va-Vb≠0, it means that the motor speed is in a rapidly changing state. At this time, it is judged that the motor is in the speed adjustment stage. At this time, the principle of quickly identifying and judging the current motor speed Va is based on the acceleration principle.

[0061] Preferably, when the motor is at a constant speed, the current motor speed Va is compared with the interval value. If Va∈{V1, Vn}, the noise reduction system actively intervenes; if Then the noise reduction system does not intervene;

[0062] When the noise reduction system intervenes, it quickly identifies and determines the current motor speed Va, and then quickly adjusts it based on the determination result, so that the motor speed can leave the noise range speed in the fastest time.

[0063] Preferably, the approach principle is: when Va∈{V1, Vn}, if Va-V1≥Vn-V1, then Va is controlled to quickly increase to a state greater than Vn; if Va-V1<Vn-V1, then Va is controlled to quickly decrease to a state less than V1, so that the motor can actively avoid the noise section speed when it is in normal operating state.

[0064] Preferably, the acceleration principle is: if the motor speed is in the adjustment state, the motor has an acceleration a = (Vt-Vo) / t, where Vt is the terminal target speed, Vo is the initial speed before acceleration, and t is the acceleration time. When the motor acceleration a≥0, Va is controlled to quickly increase to a state greater than Vn; when the motor acceleration a<0, Va is controlled to quickly decrease to a state less than V1, so that the motor can actively increase the speed in the noise section during the speed adjustment stage to quickly leave the noise section speed.

[0065] Working principle: The present invention aims to provide a method for achieving noise reduction by intelligently adjusting the motor speed so that the motor avoids the noise segment speed. In this method, the relationship data between the motor speed and noise is obtained through actual measurement. The process is to run the motor at no load and gradually increase the motor speed from 0 to the maximum speed through the motor controller. In the process of motor speed increase, the noise performance of the motor throughout the whole process is recorded by a decibel meter, and then the speed of the maximum noise range is intercepted and marked as the noise segment speed of the motor.

[0066] Then, an algorithm for avoiding noise points is designed and applied to the motor controller, enabling the motor controller to automatically control the motor according to the algorithm during operation. The logic of the algorithm is mainly based on two practical application starting points;

[0067] One is that the motor is in a constant speed state, which is usually used when the drone moves within the same altitude range. By obtaining the speed of the drone's previous measurement point and comparing it with the current speed, if the two speeds are the same, it means that the drone is in a constant speed state. At this time, the algorithm automatically determines whether the speed is in the noise segment speed. If not, the noise reduction system does not intervene. If it is in the noise segment, the algorithm sees whether the current speed is close to the maximum speed or the maximum speed of the noise segment. According to the convergence principle, the closer speed is automatically selected to increase or decrease the speed, so that the motor speed leaves the noise segment speed as quickly as possible.

[0068] The second is that the motor is in a variable speed state, which is usually used when the drone is ascending or descending. Due to the technical principle of the drone, the motor speed is increased, so that the rotor provides greater lift force, causing the drone to rise. Conversely, the motor slows down, the lift force of the rotor decreases, and the drone descends. According to this principle, by obtaining the rotational speed of the previous measurement point of the drone and comparing it with the current rotational speed, when the two rotational speeds are different, the acceleration of the two can be calculated. When the acceleration is positive, it means that the drone is in the ascending stage. At this time, by increasing the input speed, the motor speed is quickly increased, and the speed is increased from the noise segment to a higher speed; if the acceleration is negative, it means that the drone is in the descending stage. At this time, by reducing the input speed, the drone decelerates quickly, and the speed is reduced from the noise segment to a lower speed. In this way, the speed is reasonably adjusted according to the current operating state of the drone, so that the actual operating speed can meet the operating requirements while escaping from the noise segment speed.

[0069] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A motor noise suppression control method, characterized in that: The steps include: Step 1: Extract the speed point with the loudest noise during the operation of the motor; Step 2: Set the speed of the noise point to adjust the electrical signal; Step 3: Design a noise point avoidance algorithm in the motor controller. The motor automatically adjusts its speed through the algorithm to avoid the speed at the noise point, thereby achieving active noise reduction effect by reducing the time the motor is in the noise range.

2. A motor noise suppression control method according to claim 1, characterized in that: In the step 1, when extracting the rotation speed point with the largest noise during the operation of the motor, the following steps are performed: S1. Place the target motor and the decibel meter in the test space, and monitor the speed of the target motor through the tachometer; S2, running the target motor at no load, so that the motor speed is gradually accelerated from zero speed to rated speed, and obtaining the noise curve of the whole process through a decibel meter; S3. The target noise section speed is obtained by fitting the noise curve with the speed curve. At this time, the target noise section speed obtained is the speed section with the maximum noise of the motor.

3. A motor noise suppression control method according to claim 2, characterized in that: In the step 2, the input throttle signal is converted into an electronically controlled target speed signal, so that when the motor reaches the target speed, a control signal is sent to the motor controller. At this time, the motor speed is actively changed by the motor controller, so that the motor speed quickly leaves the noise section speed range.

4. The motor noise suppression control method according to claim 1, characterized in that: The sources of noise during the operation of the motor include: Mechanical noise is generated by the collision and friction between internal parts when they rotate. Without considering wear and aging, the mechanical noise at a fixed speed is a fixed value and can be measured by a decibel meter. Electromagnetic noise is caused by the interaction of the magnetic field between the stator and the rotor inside the motor, which causes the motor core to vibrate and then generates noise. The mechanical noise at a fixed speed is a fixed value and can be measured by a decibel meter. Air noise is caused by the air flow friction and vibration of the motor's actual working parts when they come into contact with the air. In addition to being affected by the motor speed, it is also related to the external air flow velocity and is a variable noise.

5. A motor noise suppression control method according to claim 4, characterized in that: When extracting the rotation speed of the motor noise point, air noise is ignored, and the common noise effect of mechanical noise and electromagnetic noise is actually detected.

6. The motor noise suppression control method according to claim 1, characterized in that: The algorithm logic of avoiding noise points is as follows:

1. Extract the speed of the noise points in the noise segment, and mark the speed as V1, V2, ..., Vn; 2. Get the current motor speed, marked as Va, and get the speed Vb of the previous measurement stage; 3. Compare the current speed. If Va-Vb=0, it means that the motor speed is in a constant state. At this time, the motor is in a normal operating state. At this time, the principle for quickly identifying and judging the current motor speed Va is based on the approach principle. When Va-Vb≠0, it means that the motor speed is in a fast changing state. At this time, it is judged that the motor is in the speed adjustment stage. At this time, the principle of fast identification and judgment of the current motor speed Va is based on the acceleration principle.

7. A motor noise suppression control method according to claim 6, characterized in that: When the motor is at a constant speed, the interval value comparison of the current motor speed Va is performed. If Va∈{V1, Vn}, the noise reduction system actively intervenes; if Then the noise reduction system does not intervene; When the noise reduction system intervenes, it quickly identifies and determines the current motor speed Va, and then quickly adjusts it according to the determination result, so that the motor speed can leave the noise section speed in the fastest time.

8. The motor noise suppression control method according to claim 7, characterized in that: The approaching principle is: when Va∈{V1, Vn}, if Va-V1≥Vn-V1, Va is controlled to be quickly increased to a state greater than Vn; If Va-V1<Vn-V1, Va is controlled to be quickly reduced to a state less than V1, so that the motor can actively avoid the noise section speed when it is in normal operation.

9. The motor noise suppression control method according to claim 6, characterized in that: The acceleration principle is: if the motor speed is in the adjustment state, the motor has an acceleration a=(Vt-Vo) / t, where Vt is the terminal target speed, Vo is the initial speed before acceleration, and t is the acceleration time. When the motor acceleration a≥0, Va is controlled to quickly increase to a state greater than Vn; when the motor acceleration a<0, Va is controlled to quickly decrease to a state less than V1, so that the motor can actively increase the speed in the noise section during the speed adjustment stage to quickly leave the noise section speed.

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