A large-torque low-speed motor speed estimation method based on quantized feedback extended state observer

Abstract

The application discloses a large-torque low-speed motor speed estimation method based on a quantized feedback extended state observer, and belongs to the technical field of low-speed motor evaluation, and comprises the following steps: S1: a control system of a motor outputs a control instruction system to operate so that the motor rotates; S2: an extended state observer observes a discrete angle position signal; S3: an observation error value is taken as a feedback signal to input the extended state observer to update a state; S4: an estimated speed is output as a final speed estimation value of the motor; in the above manner, a method capable of effectively inhibiting quantization noise, improving speed estimation precision and smoothness under ultra-low speed is provided, so that the accuracy and stability of speed measurement are effectively improved while timely response and real-time performance are ensured.

Description

Technical Field

[0001] This invention relates to the field of low-speed motor evaluation technology, specifically to a method for estimating the speed of a high-torque low-speed motor based on a quantized feedback extended state observer. Background Technology

[0002] To date, both academia and industry still face certain difficulties in accurately measuring the speed of low-speed, high-torque permanent magnet synchronous motors. This is because these motors are characterized by low speed and high torque, making it difficult for traditional speed measurement methods (such as encoders) to provide accurate speed information.

[0003] Especially under low-speed conditions, low-resolution encoders are usually used for measurement. However, due to the low resolution of the encoder, measurement errors are easily caused. Furthermore, the real-time performance of low-resolution encoders is poor due to their inherent performance limitations. Timely and accurate acquisition of motor speed is crucial for high-torque low-speed motors to provide stable and efficient high-torque output. Therefore, it is urgent to design a speed estimation method for high-torque low-speed motors based on a quantized feedback extended state observer to solve the above problems.

[0004] To address the aforementioned speed measurement problem of low-speed, high-torque permanent magnet synchronous motors, this solution designs corresponding algorithms and observers to process low-resolution sensor data. This overcomes the problems of large quantization errors, significant noise, and poor dynamic response caused by encoder discretization in existing low-speed motor speed estimation methods. It provides a method and system that effectively suppresses quantization noise and improves the accuracy and smoothness of speed estimation at ultra-low speeds, thereby significantly improving the accuracy and stability of speed measurement. This method eliminates the need for high-resolution encoders, improving speed measurement accuracy while saving costs. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the problems of large quantization error, significant noise, and poor dynamic response caused by encoder discretization in existing low-speed motor speed estimation methods by designing corresponding algorithms and observers to process low-resolution sensor data. This invention provides a method that can effectively suppress quantization noise and improve the accuracy and smoothness of speed estimation at ultra-low speeds, thereby achieving timely response to ensure real-time performance while effectively improving the accuracy and stability of speed measurement.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows: a method for estimating the speed of a high-torque low-speed motor based on a quantized feedback extended state observer, comprising the following steps:

[0007] S1: The control system of the motor outputs control commands. make The system operation causes the motor to rotate, and the actual angular position of the motor is... The encoder of the motor acquires the angular position signal of the motor in real time to obtain the angular position value of the motor. The signal acquired by the encoder of the motor is a discrete angular position signal. ;

[0008] S2: The extended state observer observes the discrete angular position signal Observations are performed, and based on the encoder resolution, the continuous angular positions generated within the extended state observer in the quantization module of the control system are obtained. Quantization function for discretization Through the quantization function Obtain the estimated angular position signal The estimated angular position signal As shown in Formula 1:

[0009] (1)

[0010] The discretization process of the quantization module is obtained through formulas 2, 3, 4, and 5:

[0011] (2)

[0012] (3)

[0013] (4)

[0014] (5)

[0015] Formula 2 is transformed into state equation formula 5 using formulas 3 and 4. The actual speed of the motor with respect to time The function, This is the torque coefficient of the motor. This is the load torque of the motor. Let be the moment of inertia of the motor. This represents the actual angular position of the motor. For the observed angular position signal, These are the continuous angular positions and velocities estimated by the extended state observer, respectively.

[0016] Formula 6 can be obtained from Formula 1 and Formula 5;

[0017] (6)

[0018] Calculate the estimated angular position signal With discrete angular position signal The error is used to obtain the observation error value. The calculation formula is shown in Formula 7:

[0019] (7);

[0020] S3: The observation error value The state update is performed by inputting the extended state observer as a feedback signal, and the state update is performed by Equation 8.

[0021] (8)

[0022] in, The extended state observer is used to estimate the continuous angular position, velocity, and total disturbance state, respectively.

[0023] This represents the number of iterations.

[0024] Observation error A function of the number of iterations;

[0025] The system sampling period;

[0026] For observer gain;

[0027] This is the estimated control gain value;

[0028] For system control input;

[0029] For quantization functions;

[0030] S4: After performing the state update, the extended state observer outputs the estimated velocity. As the final speed estimate of the motor As shown in Formula 9;

[0031] (9).

[0032] In a preferred embodiment of the present invention, the encoder is an incremental encoder that generates N counts per revolution, and the estimated angular position signal... quantization function As shown in Formula 10:

[0033] (10)

[0034] in, This is the rounding function.

[0035] In a preferred embodiment of the present invention, the signal acquired by the encoder of the motor in step S1 is a discrete angular position signal. Specifically, it includes:

[0036] Based on the encoder's resolution, the encoder determines the actual angular position of the motor. The discrete angular position signals are obtained by acquiring and discretizing the data. .

[0037] As a preferred embodiment of the present invention, the control system of the motor in step S1 outputs control commands. The system operation specifically includes:

[0038] The motor's control system outputs control commands. The system operates by providing a current signal to the motor. The actual speed of the motor is calculated according to Formula 11. Compared with actual angular position ;

[0039] (11)

[0040] in, This is the actual speed of the motor. The electromagnetic torque of the motor. This is the torque coefficient of the motor. This is the load torque of the motor. Let be the moment of inertia of the motor. This represents the actual angular position of the motor. For time.

[0041] As a preferred embodiment of the present invention, Formula 2 is obtained from Formula 11 through Laplace transform, and in Formula 2... for frequency domain signal, is the complex frequency domain variable in the Laplace transform.

[0042] As a preferred embodiment of the present invention, the discretization processing of the quantization module in step S2, obtained through formulas 2, 3, 4, and 5, further includes:

[0043] Introducing Formula 12 as a new state into Formula 5, we obtain Formula 13;

[0044] (12)

[0045] (13)

[0046] in, for frequency domain signal, The actual speed of the motor with respect to time The function, These are used to estimate the continuous angular position, velocity, and total disturbance state of the extended state observer, respectively.

[0047] As a preferred embodiment of the present invention, the extended state observer is a linear extended state observer, and its order is not equal to second order.

[0048] As a preferred embodiment of the present invention, the extended state observer is a nonlinear extended state observer with an order of not less than second order.

[0049] As a preferred embodiment of the present invention, the extended state observer is the nonlinear state shown in Formula 14;

[0050] (14)

[0051] in, The extended state observer is used to estimate the continuous angular position, velocity, and total disturbance state, respectively. , , , For the observer bandwidth, Let be a nonlinear function used to improve performance in the small error range, and its parameters are . .

[0052] As a preferred embodiment of the present invention, the extended state observer is the linear state shown in Formula 15;

[0053] (15)

[0054] in, The extended state observer is used to estimate the continuous angular position, velocity, and total disturbance state, respectively. , , , This represents the observer bandwidth.

[0055] The beneficial effects of this invention are reflected in:

[0056] 1. By explicitly introducing the encoder quantization model into the extended state observer loop, the observer can "sense" and actively compensate for quantization noise, rather than treating it as general noise and filtering it afterward. This in principle improves the estimation accuracy and stability at extremely low speeds when the position signal change is less than one minimum resolution.

[0057] 2. Velocity information is output directly and continuously as the internal state of the extended state observer, without the need for additional numerical differentiation of position. This avoids noise amplification and delay caused by the differentiation process, resulting in a faster dynamic response and improved real-time velocity measurement.

[0058] 3. The extended state observer itself has the ability to estimate and compensate for total disturbances, so it is not sensitive to changes in motor parameters and has strong robustness. At the same time, the method of this invention closely fits the discretization and quantization characteristics of digital control systems, has a clear algorithm structure, and is easy to implement and debug in microprocessors. It has a significant effect on solving the "creeping" or "jumping" phenomenon in ultra-low speed servo systems. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the overall process and system structure of the invention;

[0060] Figure 2 This is a diagram of the transfer function model of a PMSM motor;

[0061] Figure 3 This is a schematic diagram of the discrete angular position signal of the present invention;

[0062] Figure 4 This is a block diagram of the general extended state observer (ESO) for estimating motor speed;

[0063] Figure 5 This is a block diagram of the motor speed estimation method of the present invention;

[0064] Figure 6 This is a simulation diagram of motor speed estimation using a standard extended state observer (ESO).

[0065] Figure 7 This is a simulation diagram of motor speed estimation based on the present invention. Detailed Implementation

[0066] The invention will now be described in further detail with reference to the accompanying drawings.

[0067] Combined with appendix Figure 1-7 As shown, a method for estimating the speed of a high-torque low-speed motor based on a quantized feedback extended state observer includes the following steps:

[0068] S1: The control system of the motor outputs control commands. make The system operation causes the motor to rotate, and the actual angular position of the motor is... The encoder of the motor acquires the angular position signal of the motor in real time to obtain the angular position value of the motor. The signal acquired by the encoder of the motor is a discrete angular position signal. Specifically, in practice, the encoder collects the actual angular position signal. That is, discrete angular position signal ;

[0069] Specifically:

[0070] The motor's control system outputs control commands. The system operates by providing a current signal to the motor. The actual speed of the motor is calculated according to Formula 11. Compared with actual angular position ;

[0071] (11)

[0072] in, This is the actual speed of the motor. The electromagnetic torque of the motor. This is the torque coefficient of the motor. This is the load torque of the motor. Let be the moment of inertia of the motor. This represents the actual angular position of the motor. For time;

[0073] Based on the encoder's resolution, the encoder determines the actual angular position of the motor. The discrete angular position signals are obtained by acquiring and discretizing the data. ;

[0074] S2: The extended state observer observes the discrete angular position signal Observations are performed, and based on the encoder resolution, the continuous angular positions generated within the extended state observer in the quantization module of the control system are obtained. Quantization function for discretization Wherein, given the parameters of the extended state observer and the motor, the continuous angular position It can be clearly known that it represents a signal that is continuous in time and infinitely precise in amplitude, through the quantization function. Obtain the estimated angular position signal The estimated angular position signal As shown in Formula 1:

[0075] (1)

[0076] The discretization process of the quantization module is obtained through formulas 2, 3, 4, and 5:

[0077] (2)

[0078] (3)

[0079] (4)

[0080] (5)

[0081] Formula 2 is obtained from Formula 11 through Laplace transform. Formula 2 is then transformed into the state equation Formula 5 using Formulas 3 and 4. for frequency domain signal, For the complex frequency domain variables in the Laplace transform, The actual speed of the motor with respect to time The function, This is the torque coefficient of the motor. This is the load torque of the motor. Let be the moment of inertia of the motor. This represents the actual angular position of the motor. For the observed angular position signal, These are the continuous angular positions and velocities estimated by the extended state observer, respectively.

[0082] Formula 6 can be obtained from Formula 1 and Formula 5;

[0083] (6)

[0084] Calculate the estimated angular position signal With discrete angular position signal The error is used to obtain the observation error value. The calculation formula is shown in Formula 7:

[0085] (7);

[0086] Specifically:

[0087] The encoder is an incremental encoder that generates N counts per revolution, then the estimated angular position signal quantization function As shown in Formula 10:

[0088] (10)

[0089] in, This is the rounding function;

[0090] Introducing Formula 12 as a new state into Formula 5, we obtain Formula 13;

[0091] (12)

[0092] (13)

[0093] in, for frequency domain signal, The actual speed of the motor with respect to time The function, Specifically, the extended state observer estimates continuous angular position, velocity, and total disturbance state. This refers to a new state that is an extension of the original system.

[0094] S3: The observation error value The state update is performed by inputting the extended state observer as a feedback signal, and the state update is performed by Equation 8.

[0095] (8)

[0096] in, The extended state observer is used to estimate the continuous angular position, velocity, and total disturbance state, respectively.

[0097] This represents the number of iterations.

[0098] Observation error A function of the number of iterations;

[0099] The system sampling period;

[0100] For observer gain;

[0101] This is the estimated control gain value;

[0102] For system control input;

[0103] For quantization functions;

[0104] S4: After performing the state update, the extended state observer outputs the estimated velocity. As the final speed estimate of the motor As shown in Formula 9;

[0105] (9)

[0106] The extended state observer is a linear extended state observer with an order not equal to second order, or the extended state observer is a nonlinear extended state observer with an order not lower than second order.

[0107] When the extended state observer is a linear extended state observer, the extended state observer is the linear state shown in Equation 15:

[0108] (15)

[0109] in, The extended state observer is used to estimate the continuous angular position, velocity, and total disturbance state, respectively. , , , For observer bandwidth;

[0110] When the extended state observer is a nonlinear extended state observer, the extended state observer is the nonlinear state shown in Formula 14;

[0111] (14)

[0112] in, The extended state observer is used to estimate the continuous angular position, velocity, and total disturbance state, respectively. , , , For the observer bandwidth, Let be a nonlinear function used to improve performance in the small error range, and its parameters are . .

[0113] Example:

[0114] Based on Formula 11, construct the motor system model, see attached. Figure 2 Load torque Motor torque coefficient Moment of inertia of motor In the simulation model, the sampling time interval of the simulated encoder is 0.1s, and the given current is... The discrete angular position signal is obtained. , See Figure 3 ;

[0115] Based on formulas 3, 4, and 5, construct a model for the extended state observer as follows: Figure 4 As shown, for discrete angular position signals Observations were conducted, among which , , , The observer bandwidth is set to 10 Hz. The velocity value can then be estimated. The comparison diagram with the actual speed signal of the motor is shown below. Figure 6 As shown;

[0116] Based on the original extended state observer model, the fundamental encoder resolution is improved to handle the continuous angular positions generated within the extended state observer. Discretize the data and build an improved observer model, such as... Figure 5 As shown, at this time, the discrete angular position signal By observing, the velocity value can be estimated. The comparison graph with the actual speed signal of the motor is as follows: Figure 7 As shown;

[0117] like Figure 6 As shown, the estimated speed is affected by the encoder, fluctuating significantly at low speeds and failing to reflect the true speed information. Figure 7 The results show that, during the speed estimation process, adding a quantization function results in almost no deviation between the actual speed and the estimated speed, thus correctly estimating the motor speed.

[0118] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A large torque low speed motor speed estimation method based on quantized feedback extended state observer, characterized in that, Includes the following steps: S1: The control system of the motor outputs control commands. make The system operation causes the motor to rotate, and the actual angular position of the motor is... The encoder of the motor acquires the angular position signal of the motor in real time to obtain the angular position value of the motor. The signal acquired by the encoder of the motor is a discrete angular position signal. ; S2: The extended state observer observes the discrete angular position signal Observations are performed, and based on the encoder resolution, the continuous angular positions generated within the extended state observer in the quantization module of the control system are obtained. Quantization function for discretization Through the quantization function Obtain the estimated angular position signal The estimated angular position signal As shown in Formula 1: （1） The discretization process of the quantization module is obtained through formulas 2, 3, 4, and 5: （2） （3） （4） （5） Formula 2 is transformed into state equation formula 5 using formulas 3 and 4. The actual speed of the motor with respect to time The function, This is the torque coefficient of the motor. This is the load torque of the motor. Let be the moment of inertia of the motor. This represents the actual angular position of the motor. For the observed angular position signal, These are the continuous angular positions and velocities estimated by the extended state observer, respectively. Formula 6 can be obtained from Formula 1 and Formula 5; （6） Calculate the estimated angular position signal With discrete angular position signal The error is used to obtain the observation error value. The calculation formula is shown in Formula 7: （7）； S3: The observation error value The state update is performed by inputting the extended state observer as a feedback signal, and the state update is performed by Equation 8. （8） in, The extended state observer is used to estimate the continuous angular position, velocity, and total disturbance state, respectively. This represents the number of iterations. Observation error A function of the number of iterations; The system sampling period; For observer gain; This is the estimated control gain value; For system control input; For quantization functions; S4: After performing the state update, the extended state observer outputs the estimated velocity. As the final speed estimate of the motor As shown in Formula 9; （9）。 2. The method for estimating the speed of a high-torque low-speed motor based on a quantized feedback extended state observer according to claim 1, characterized in that: The encoder is an incremental encoder that generates N counts per revolution, then the estimated angular position signal quantization function As shown in Formula 10: （10） in, This is the rounding function.

3. The speed estimation method for a high-torque low-speed motor based on a quantized feedback extended state observer according to claim 1, characterized in that: The signal acquired by the encoder of the motor in S1 is a discrete angular position signal. Specifically, it includes: Based on the encoder's resolution, the encoder determines the actual angular position of the motor. The discrete angular position signals are obtained by acquiring and discretizing the data. .

4. The speed estimation method for a high-torque low-speed motor based on a quantized feedback extended state observer according to claim 1, characterized in that: The control system of the motor in S1 outputs control commands. The system operation specifically includes: The motor's control system outputs control commands. The system operates by providing a current signal to the motor. The actual speed of the motor is calculated according to Formula 11. Compared with actual angular position ; （11） in, This is the actual speed of the motor. The electromagnetic torque of the motor. This is the torque coefficient of the motor. This is the load torque of the motor. Let be the moment of inertia of the motor. This represents the actual angular position of the motor. For time.

5. The speed estimation method for a high-torque low-speed motor based on a quantized feedback extended state observer according to claim 4, characterized in that: Formula 2 is obtained from Formula 11 through Laplace transform. In Formula 2... for frequency domain signal, is the complex frequency domain variable in the Laplace transform.

6. The method for estimating the speed of a high-torque low-speed motor based on a quantized feedback extended state observer according to claim 5, characterized in that: The discretization process of the quantization module in S2, obtained through formulas 2, 3, 4, and 5, further includes: Introducing Formula 12 as a new state into Formula 5, we obtain Formula 13; （12） （13） in, for frequency domain signal, The actual speed of the motor with respect to time The function, These are used to estimate the continuous angular position, velocity, and total disturbance state of the extended state observer, respectively.

7. The method for estimating the speed of a high-torque low-speed motor based on a quantized feedback extended state observer according to claim 1, characterized in that: The extended state observer is a linear extended state observer, and its order is not equal to second order.

8. The speed estimation method for a high-torque low-speed motor based on a quantized feedback extended state observer according to claim 1, characterized in that: The extended state observer is a nonlinear extended state observer, and its order is not lower than second order.

9. The speed estimation method for a high-torque low-speed motor based on a quantized feedback extended state observer according to claim 7, characterized in that: The extended state observer is the nonlinear state shown in Equation 14; （14） in, The extended state observer is used to estimate the continuous angular position, velocity, and total disturbance state, respectively. , , , For the observer bandwidth, Let be a nonlinear function used to improve performance in the small error range, and its parameters are . .

10. The method for estimating the speed of a high-torque low-speed motor based on a quantized feedback extended state observer according to claim 8, characterized in that: The extended state observer is the linear state shown in Equation 15; （15） in, The extended state observer is used to estimate the continuous angular position, velocity, and total disturbance state, respectively. , , , This represents the observer bandwidth.

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