A method of motor control based on predicted encoder readings

Abstract

This invention provides a motor control method based on predictive encoder readings, comprising: calculating the predicted encoder reading at the next sampling time based on the sampling interval of the motor speed and the encoder feedback reading using an encoder prediction algorithm; determining the range of the encoder predicted reading at the next sampling time based on the predicted reading and the allowable deviation of the system corresponding to the motor control method; acquiring the actual encoder reading at the next sampling time and comparing the actual reading with the range of the encoder predicted reading to obtain a comparison result; and controlling the motor accordingly based on the comparison result and in conjunction with a motor control strategy based on the encoder state. This method enables the controller to monitor the encoder state throughout the entire process, and by classifying deviations, it achieves classified control of the motor under different deviations, improving the reliability and safety of motor control.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a motor control method based on predictive encoder readings. Background Technology

[0002] Currently, complex equipment systems have high requirements for precise positioning of equipment. To achieve a certain level of positioning accuracy, servo motors are a commonly used control method for driving equipment. The main control methods for servo motors include speed loop control and position loop control. Position loop control uses the current motor position as a calculation parameter to more accurately describe the movement of the equipment, so it has a wider range of applications.

[0003] Position loop control mainly relies on encoder readings to feedback the current position of the device. However, due to the lack of encoder status detection, when the encoder malfunctions and the returned data fluctuates abnormally, the control system may misjudge the device's operating status, leading to serious consequences such as motor overrunning. Therefore, in a position loop motor control system, it is necessary to detect the encoder while ensuring the reliable operation of the system to the greatest extent possible and reducing the false alarm rate. Summary of the Invention

[0004] In view of the above-mentioned problems in the prior art, the present invention provides a motor control method based on predictive encoder readings. In this method, the controller calculates the range of encoder readings that may be fed back at the next interruption time by using the motor speed and the encoder feedback reading interval, and compares it with the actual encoder feedback as the basis for judging the encoder status. This enables the controller to monitor the encoder status throughout the process. At the same time, by classifying the deviation, it realizes classified control of the motor under different deviations, thereby improving the reliability and safety of motor control.

[0005] This invention provides a motor control method based on predictive encoder readings, comprising:

[0006] Based on the sampling interval time of the motor speed and encoder feedback reading, the predicted reading of the encoder at the next sampling moment is calculated according to the encoder prediction algorithm.

[0007] Based on the predicted reading and the allowable deviation of the system corresponding to the motor control method, the range of the encoder predicted reading at the next sampling time is determined;

[0008] The actual reading of the encoder is acquired at the next sampling time, and the actual reading is compared with the predicted reading range of the encoder to obtain the comparison result;

[0009] Based on the comparison results and in conjunction with the motor control strategy based on the encoder status, the motor is controlled accordingly.

[0010] In some embodiments of the present invention, the encoder prediction algorithm specifically includes:

[0011] The prediction method for when the motor speed is in the state-holding phase is given by the following formula:

[0012] x n =x n-1 +v n-1 ×T s

[0013] In the formula: x n For the encoder to predict the reading at the next moment, x n-1 v represents the actual encoder feedback reading at the previous moment. n-1 T represents the motor control speed at the previous moment. s This represents the system encoder acquisition cycle.

[0014] In some embodiments of the present invention, the encoder prediction algorithm further includes:

[0015] The prediction algorithm for when the motor speed is at the end of acceleration is given by the following formula:

[0016]

[0017] In the formula: X1 is the motor's position at the end of acceleration, V y This refers to the speed during the constant speed phase of the motor.

[0018] In some embodiments of the present invention, the encoder prediction algorithm further includes:

[0019] The prediction algorithm for when the motor speed is at the end of a constant speed range is given by the following formula:

[0020]

[0021] In the formula: X2 is the position of the motor at the end of the uniform motion, and a is the acceleration of the motor during the deceleration phase.

[0022] In some embodiments of the present invention, determining the encoder prediction reading range for the next sampling time based on the predicted reading and the allowable deviation of the system corresponding to the motor control method includes:

[0023] Based on the predicted result x n The encoder's predicted reading range {x} is formed by the system's set allowable deviation λ. n -λ,x n +λ}.

[0024] In some embodiments of the present invention, the step of controlling the motor accordingly based on the comparison result and in conjunction with the motor control strategy of the encoder state includes:

[0025] If the actual encoder reading does not exceed the encoder's predicted reading range, the encoder is considered to be in normal condition. The speed control system then calculates the motor speed for the next moment based on the actual encoder reading.

[0026] In some embodiments of the present invention, the step of controlling the motor accordingly based on the comparison result and in conjunction with the motor control strategy of the encoder state further includes:

[0027] If the actual encoder reading exceeds the encoder's predicted reading range, and the absolute value of the deviation Δx is less than the system's set threshold δ, speed control is performed according to the predicted reading for the next sampling interval, the number of out-of-tolerance events is incremented by one, and the encoder reading at the next sampling time is predicted.

[0028] If the encoder reading returns to the normal range in the next moment, the encoder is considered to be normal, and the number of out-of-tolerance counts is reset to zero.

[0029] If the error still occurs but the absolute value is small, then the operation will be carried out according to the previous sampling interval, and so on.

[0030] If the encoder exceeds the tolerance for three consecutive sampling intervals, the controller sends an encoder fault signal and issues a stop command to the driver.

[0031] In some embodiments of the present invention, the step of controlling the motor accordingly based on the comparison result and in conjunction with the motor control strategy of the encoder state further includes:

[0032] If the encoder reading exceeds the system's predicted range and the absolute value of the deviation Δx is greater than or equal to the system's set threshold δ, the encoder is considered to be in an abnormal state. The controller then sends an encoder fault signal and issues a stop command to the driver.

[0033] Compared with the prior art, the beneficial effects of the motor control method based on predictive encoder readings provided by the embodiments of the present invention are as follows: it can be widely applied in military and civilian applications. In the position loop control system of the motor, it not only realizes the prediction of encoder readings and the soft stop of the motor under abnormal conditions, but also classifies the motor for control by different degrees of encoder reading deviation. This not only realizes encoder detection, but also avoids the phenomenon of false stop caused by instantaneous encoder fluctuations, thereby improving the safety and reliability of the entire motor control system. Attached Figure Description

[0034] Figure 1 A schematic diagram of the motor speed control curve in the motor control method based on predictive encoder readings provided in an embodiment of the present invention;

[0035] Figure 2This is a flowchart illustrating the motor control method based on predictive encoder readings provided in an embodiment of the present invention. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Various embodiments and features of this application are described herein with reference to the accompanying drawings.

[0038] These and other features of this application will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0039] It should also be understood that although this application has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of this application, which have the features described in the claims and are therefore all within the scope of protection defined herein.

[0040] The above and other aspects, features and advantages of this application will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0041] Specific embodiments of this application are described below with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of this application, which can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to ascertain the true intent based on the user's historical operations, and to avoid unnecessary or redundant details that would obscure this application. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely serve as the basis and representative basis for the claims to teach those skilled in the art to use this application in various ways with substantially any suitable detailed structure.

[0042] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in other embodiments,” all of which may refer to one or more of the same or different embodiments according to this application.

[0043] This invention provides a motor control method based on predictive encoder readings, applicable to motor position closed-loop control systems that rely on encoder readings of the motor's current position and control the motor speed via position signals to achieve precise stopping. This method reduces motor runaway caused by encoder malfunctions by predicting encoder readings, thus improving motor operation safety. Figure 1 and Figure 2 As shown, the method includes:

[0044] Based on the sampling interval time of the motor speed and encoder feedback reading, the predicted reading of the encoder at the next sampling moment is calculated according to the encoder prediction algorithm.

[0045] Based on the predicted reading and the allowable deviation of the system corresponding to the motor control method, the range of the encoder predicted reading at the next sampling time is determined;

[0046] The actual reading of the encoder is acquired at the next sampling time, and the actual reading is compared with the predicted reading range of the encoder to obtain the comparison result;

[0047] Based on the comparison results and in conjunction with the motor control strategy based on the encoder status, the motor is controlled accordingly.

[0048] In the above embodiment, the controller calculates the range of encoder readings that may be fed back by the encoder at the next interruption time by using the motor speed and the encoder feedback reading interval, and compares it with the actual encoder feedback as the basis for judging the encoder status. This enables the controller to monitor the encoder status throughout the process. At the same time, by classifying the deviation, it realizes classified control under different motor deviations, which improves the reliability and safety of motor control.

[0049] The above method mainly employs three aspects: encoder prediction algorithm, encoder state detection algorithm, and motor control strategy based on encoder state. Specifically, the encoder prediction algorithm uses parameters such as the system's encoder sampling frequency, the current motor speed, and the motor speed control curve to calculate and predict the encoder reading at the next sampling moment. Furthermore, it iterates step-by-step using the difference between historical predicted data and actual sampled data to improve prediction accuracy. Figure 1 The graph shows the motor speed control curve, which can be divided into three parts: acceleration, constant speed, and deceleration. Therefore, encoder reading prediction includes not only the prediction of readings during the state holding phase but also the prediction of encoder readings at the curve inflection points. Thus, it is necessary to classify and calculate these three states.

[0050] Specifically, the prediction method for the motor speed in the state-holding phase is formulated as follows:

[0051] x n =x n-1 +v n-1 ×T s

[0052] In the formula: x n For the encoder to predict the reading at the next moment, x n-1 v represents the actual encoder feedback reading at the previous moment. n-1 T represents the motor control speed at the previous moment. s This represents the system encoder acquisition cycle.

[0053] The prediction algorithm for when the motor speed is at the end of acceleration is given by the following formula:

[0054]

[0055] In the formula: X1 is the motor's position at the end of acceleration, V y This refers to the speed during the constant speed phase of the motor.

[0056] The prediction algorithm for when the motor speed is at the end of a constant speed range is given by the following formula:

[0057]

[0058] In the formula: X2 is the position of the motor at the end of the uniform motion, and a is the acceleration of the motor during the deceleration phase.

[0059] The encoder state detection algorithm determines the encoder predicted reading range for the next sampling moment based on the predicted reading and the allowable deviation of the system corresponding to the motor control method, including:

[0060] Based on the predicted result x n The encoder's predicted reading range {x} is formed by the system's set allowable deviation λ. n -λ,x n +λ}, after the actual encoder reading is collected, the encoder reading is judged to be normal by detecting whether the actual reading exceeds the predicted range.

[0061] In this embodiment, the motor control strategy is divided into three cases based on the encoder's actual reading and predicted range: normal, small out-of-tolerance value, and large out-of-tolerance value. The motor control strategy, based on the comparison result and combined with the encoder state, performs corresponding motor control, including:

[0062] If the actual encoder reading does not exceed the predicted range, and its status is judged to be normal, the speed control system will calculate the motor speed for the next moment according to the actual encoder reading.

[0063] When the encoder reading exceeds the system's predicted range and the absolute value of the deviation Δx is less than the system's set threshold δ, in order to rule out the possibility that the out-of-tolerance phenomenon is caused by short-term acquisition error of the encoder, the system performs speed control for the next cycle according to the predicted value, increments the out-of-tolerance count by one, and predicts the encoder reading at the next moment. When the encoder reading returns to the normal range at the next moment, the encoder is considered to be normal, and the out-of-tolerance count is cleared to zero. If the out-of-tolerance situation still occurs but the absolute value is small, the operation of the previous cycle is performed, and so on. When the encoder has out-of-tolerance situations for three consecutive sampling cycles, the controller sends an encoder fault signal and issues a stop command to the driver.

[0064] When the encoder reading exceeds the system's predicted range and the absolute value of the deviation Δx is greater than or equal to the system's set threshold δ, the encoder is considered to be in an abnormal state. In this case, the controller sends an encoder fault signal and issues a stop command to the driver.

[0065] As can be seen from the above technical solution, the motor control method based on dynamic encoder reading prediction technology uses the encoder reading not only as a position sensor component for motor control, but also as a basis for determining the normal operation of the motor. This not only achieves traditional closed-loop position control but also adds judgment conditions for safe motor operation, improving system reliability. Furthermore, it adds an encoder feedback prediction unit within the motor controller to predict the range of the encoder reading at the next acquisition moment. While acquiring the encoder reading, it also judges the correctness of the reading through the predicted value, avoiding motor runaway due to encoder failure. In addition, while detecting the encoder status, it uses the encoder status as a necessary condition for whether the motor is operating normally. When the system determines that the encoder status is abnormal, it classifies the deviation and adopts different control methods for different deviation situations. This not only avoids motor runaway but also minimizes the impact of instantaneous small-range errors, preventing accidental shutdowns.

[0066] The motor control method based on predictive encoder readings provided in this embodiment can be widely applied in both military and civilian applications. In the motor position loop control system, it not only realizes the prediction of encoder readings and the soft shutdown of the motor under abnormal conditions, but also classifies the motor for control based on the different degrees of encoder reading deviation. This achieves encoder detection while avoiding false shutdowns caused by instantaneous encoder fluctuations, thus improving the safety and reliability of the entire motor control system.

[0067] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A motor control method based on predictive encoder readings, characterized in that, include: Based on the sampling interval time of the motor speed and encoder feedback reading, the predicted reading of the encoder at the next sampling moment is calculated according to the encoder prediction algorithm. Based on the predicted reading and the allowable deviation of the system corresponding to the motor control method, the range of the encoder predicted reading at the next sampling time is determined; The actual reading of the encoder is acquired at the next sampling time, and the actual reading is compared with the predicted reading range of the encoder to obtain the comparison result; Based on the comparison results and in conjunction with the motor control strategy based on the encoder status, the motor is controlled accordingly. The encoder prediction algorithm specifically includes: The prediction method for when the motor speed is in the state-holding phase is given by the following formula: x n =x n-1 +v n-1 ×T s In the formula: x n For the encoder to predict the reading at the next moment, x n-1 v represents the actual encoder feedback reading at the previous moment. n-1 T represents the motor control speed at the previous moment. s This refers to the system encoder acquisition cycle; The encoder prediction algorithm further includes: The prediction algorithm for when the motor speed is at the end of acceleration is given by the following formula: In the formula: X1 is the motor's position at the end of acceleration, V y This refers to the speed during the constant speed phase of the motor. The encoder prediction algorithm further includes: The prediction algorithm for when the motor speed is at the end of a constant speed range is given by the following formula: In the formula: X2 is the position of the motor at the end of the uniform motion, and a is the acceleration of the motor during the deceleration phase.

2. The motor control method based on predictive encoder readings according to claim 1, characterized in that, The step of determining the encoder predicted reading range for the next sampling time based on the predicted reading and the allowable deviation of the system corresponding to the motor control method includes: Based on the predicted result x n The encoder's predicted reading range {x} is formed by the system's set allowable deviation λ. n -λ,x n +λ}.

3. The motor control method based on predictive encoder readings according to claim 2, characterized in that, The motor is controlled accordingly based on the comparison result and the motor control strategy in conjunction with the encoder state, including: If the actual encoder reading does not exceed the encoder's predicted reading range, the encoder is considered to be in normal condition. The speed control system then calculates the motor speed for the next moment based on the actual encoder reading.

4. The motor control method based on predictive encoder readings according to claim 3, characterized in that, The step of controlling the motor based on the comparison result and in conjunction with the motor control strategy of the encoder state also includes: If the actual encoder reading exceeds the encoder's predicted reading range, and the absolute value of the deviation Δx is less than the system's set threshold δ, speed control is performed according to the predicted reading for the next sampling interval, the number of out-of-tolerance events is incremented by one, and the encoder reading at the next sampling time is predicted. If the encoder reading returns to the normal range in the next moment, the encoder is considered to be normal, and the number of out-of-tolerance counts is reset to zero. If the error still occurs but the absolute value is small, then the operation will be carried out according to the previous sampling interval, and so on. If the encoder exceeds the tolerance for three consecutive sampling intervals, the controller sends an encoder fault signal and issues a stop command to the driver.

5. The motor control method based on predictive encoder readings according to claim 4, characterized in that, The step of controlling the motor based on the comparison result and in conjunction with the motor control strategy of the encoder state also includes: If the encoder reading exceeds the system's predicted range and the absolute value of the deviation Δx is greater than or equal to the system's set threshold δ, the encoder is considered to be in an abnormal state. The controller then sends an encoder fault signal and issues a stop command to the driver.

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