A method and system for secondary calibration of an encoder

Abstract

The application discloses a secondary calibration method and system of an encoder, which comprises the following steps: calculating a first set of calibration parameters through an internal self-calibration program after the encoder is installed; collecting and processing data of the encoder through a servo motor and a counter-drag platform, and generating a second set of calibration parameters; and providing position information through linear fitting in combination with the first set of calibration parameters and the second set of calibration parameters when a device where the encoder is located is normally working. The method can improve the accuracy of the encoder, and solve the problems of poor flexibility and the incapability of eliminating system-level errors through built-in calibration.

Description

Technical Field

[0001] This invention relates to the field of encoder technology, and in particular to a method and system for secondary calibration of an encoder. Background Technology

[0002] In modern precision motion control applications such as servo motors, robot modules, and humanoid robots, high-precision rotary encoders play a crucial role. They ensure accurate positioning and speed control of the system by providing precise position feedback. However, to achieve this goal, inherent errors in the encoder must be addressed, including but not limited to zero-position deviation, gain error, and quadrature error. Therefore, encoders typically require self-calibration before leaving the factory to eliminate these errors.

[0003] Current typical calibration methods involve mounting the encoder onto a standard motor and using a high-precision drive source to bring it to a constant speed of rotation. In this state, the encoder's built-in self-calibration program is triggered. This program is responsible for collecting error data and calculating compensation parameters, ultimately storing these parameters in the encoder's own non-volatile memory.

[0004] While effective, this method has several limitations. First, the limitations of the encoder's internal chip performance, particularly its limited storage space and computing power, restrict the application of more complex error modeling and compensation algorithms. Besides the encoder itself, signal conditioning circuitry, ADC (Analog-to-Digital Converter) conversion errors, and mechanical installation errors such as insufficient concentricity and shaft misalignment also affect the overall system's output accuracy, and existing calibration methods cannot comprehensively cover these aspects. Once the encoder module is assembled, adjustments or recalibrations during subsequent use are difficult and inconvenient, making it difficult to meet the needs of different application scenarios or cope with changes caused by temperature drift, component aging, and other factors. Even encoders from the same production batch may exhibit significant differences in overall performance when used with different drivers or microcontrollers, posing a challenge to ensuring the consistency and reliability of the entire control system.

[0005] Therefore, it is necessary to design a new method to improve the accuracy of the encoder and solve the problems of built-in calibration failing to eliminate system-level errors and lacking flexibility. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a secondary calibration method and system for encoders.

[0007] To solve the above-mentioned technical problems, the objective of this invention is achieved through the following technical solution: providing a secondary calibration method for an encoder, comprising: After the encoder is installed, the first set of calibration parameters is calculated through the internal self-calibration program; The encoder data is collected and processed via a servo motor and a drag platform, and a second set of calibration parameters is generated. When the device containing the encoder is operating normally, position information is provided through linear fitting by combining the first set of calibration parameters and the second set of calibration parameters.

[0008] The further technical solution is as follows: after the encoder is installed, the first set of calibration parameters is calculated through an internal self-calibration program, including: After the encoder is installed, the motor is controlled by the sensorless controller to drive the encoder to rotate at a constant speed and trigger the encoder's internal self-calibration program to perform the initial calibration. After the initial calibration is completed, the encoder calculates the first set of calibration parameters and saves the first set of calibration parameters in the encoder's non-volatile memory.

[0009] Its further technical solution is as follows: the encoder data is collected and processed through the servo motor and the dragging platform, and a second set of calibration parameters is generated, including: The module under test and the servo motor are mechanically connected to the drag platform, with their axes aligned and securely fixed. Control the servo motor to run at a stable speed, and synchronously collect the raw output data of the encoder; The original output data is processed using a linear fitting method. A servo motor is used to move the module to different speed points to evaluate the range, variance, or standard deviation at different speeds and ensure that the range, variance, or standard deviation is within an acceptable range. The second set of calibration parameters is calculated based on the system-level error model and stored in the non-volatile memory of the main controller.

[0010] The further technical solution is as follows: the module under test includes a motor and a main control board.

[0011] The further technical solution is as follows: after processing the original output data using a linear fitting method, moving the module to different speed points using a servo motor, evaluating the range, variance, or standard deviation at different speeds, and ensuring that the range, variance, or standard deviation is within an acceptable range, it further includes: If at least one of the range, variance, or standard deviation is outside the acceptable range, the control servo motor is restarted to run at a stable speed, and the original output data of the encoder is collected synchronously.

[0012] The further technical solution is as follows: when the device where the encoder is located is working normally, position information is provided through linear fitting by combining the first set of calibration parameters and the second set of calibration parameters, including: When the device containing the encoder is working normally, the first set of calibration parameters after the encoder has undergone initial calibration is read in real time, and then the second set of calibration parameters is read from its own Flash. The two are then linearly fitted to obtain the position information.

[0013] In addition, to overcome the shortcomings of the prior art, the present invention also provides a secondary calibration system for an encoder, which uses the above-mentioned secondary calibration method for an encoder.

[0014] The further technical solution includes: a module under test, a servo motor, and a dragging platform; the module under test and the servo motor are respectively connected to the dragging platform.

[0015] The further technical solution includes: a speed detection device, which is connected to the module under test and the servo motor respectively.

[0016] The further technical solution includes: a leveling device and a base, wherein the leveling device is connected to the towing platform, there are two towing platforms, and the towing platforms are connected to the base.

[0017] The advantages of this invention compared to existing technologies are as follows: After encoder installation, this invention calculates a first set of calibration parameters using an internal self-calibration program to correct initial errors. Then, it utilizes a servo motor and a towing platform to collect encoder data during actual operation and generate a second set of calibration parameters to compensate for system-level errors generated during operation. When the equipment is operating normally, these two sets of parameters are combined and linear fitting is used to provide precise position information. This method not only effectively solves the system-level error problem that built-in calibration cannot eliminate, but also significantly improves the system's flexibility and adaptability because the calibration parameters can be flexibly adjusted and updated in the main controller, ultimately achieving a significant improvement in encoder accuracy.

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a secondary calibration process for an encoder provided in an embodiment of the present invention; Figure 2 A schematic diagram of a linear fitting curve provided for an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a secondary calibration system for an encoder provided in an embodiment of the present invention; Explanation of the markings in the image: 1. Module to be calibrated; 2. Servo motor; 3. Speed ​​monitoring equipment; 4. Base; 5. Leveling device; 6. Traction platform. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0023] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0024] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0025] In the field of modern precision motion control, high-precision rotary encoders are crucial for ensuring accurate positioning and speed control of servo motors, robot modules, and humanoid robots. However, their application is limited by various inherent errors such as zero-position deviation, gain error, and quadrature error. While current calibration methods can eliminate these errors to some extent by mounting the encoder on a standard motor and using a high-precision drive source for self-calibration, limitations in the encoder's internal chip performance and the inability to fully cover signal conditioning circuitry, ADC conversion errors, and mechanical installation errors make it difficult to achieve more complex error modeling and compensation. Furthermore, subsequent adjustments and recalibrations after encoder module assembly are inconvenient, and products from the same production batch may perform significantly differently in different application scenarios or when used in conjunction with other hardware, posing challenges to the consistency and reliability of the control system.

[0026] Therefore, this invention provides a secondary calibration method for encoders, which improves encoder accuracy and solves the problems of built-in calibration failing to eliminate system-level errors and lacking flexibility.

[0027] Specifically, this encoder secondary calibration method improves encoder accuracy by combining internal self-calibration and external system-level calibration. First, after encoder installation, a sensorless controller drives its rotation, and the internal self-calibration program calculates the first set of calibration parameters to eliminate basic errors. Then, through a servo motor 2 and a dragging platform 6, encoder data is collected under actual working conditions and processed using methods such as linear fitting to generate a second set of calibration parameters targeting system-level errors. During normal equipment operation, these two sets of parameters are combined to provide more accurate position information. This method not only solves system-level error problems that built-in calibration cannot cover, such as signal conditioning circuit errors, ADC conversion errors, and mechanical installation errors, but also improves the flexibility and adaptability of the calibration process, ensuring high accuracy and consistency across different application scenarios. When performance indicators are detected to be outside the acceptable range, the calibration steps can be re-executed to ensure accuracy.

[0028] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0029] Please see Figure 1 A secondary calibration method for an encoder includes steps S110 to S130.

[0030] S110. After the encoder is installed, the first set of calibration parameters is calculated through the internal self-calibration program.

[0031] In this embodiment, after the encoder is installed, the motor is controlled by the sensorless controller to drive the encoder to rotate at a constant speed, and the self-calibration program inside the encoder is triggered to perform the initial calibration. After the initial calibration is completed, the encoder calculates the first set of calibration parameters and saves the first set of calibration parameters in the encoder's non-volatile memory.

[0032] In this embodiment, the first set of calibration parameters refers to a set of correction data calculated by the encoder through its internal self-calibration program to compensate for inherent errors generated during manufacturing and installation.

[0033] Specifically, after the encoder is securely installed, a sensorless controller is used to control the motor to run at a constant speed. "Sensorless" here refers to a method that does not rely on external sensors for position or speed feedback, but rather estimates the motor's state through algorithms. This control method ensures that the motor drives the encoder to rotate at a stable rate, thus providing a stable and repeatable operating environment for subsequent self-calibration.

[0034] When the motor drives the encoder to rotate at a constant speed, it triggers a pre-set self-calibration program within the encoder. This self-calibration program is a self-testing mechanism designed by the encoder manufacturer, capable of automatically identifying and compensating for fixed deviations or errors caused by the manufacturing process, material properties, etc. This process typically involves measuring and analyzing the difference between the encoder output signal and the theoretical value, and adjusting the internal parameters accordingly.

[0035] After completing the self-calibration process described above, the encoder calculates a set of calibration parameters based on the collected data. These parameters represent error correction information specific to this particular encoder unit, designed to improve its accuracy and reliability. This set of calibration parameters is then stored in the encoder's built-in non-volatile memory (e.g., Flash memory). This ensures that this crucial calibration data is not lost even during power outages and can be directly retrieved for subsequent use, guaranteeing that the device operates at its optimal state every time it is started.

[0036] In this way, the initial calibration not only solves the accuracy problems caused by individual encoder differences, but also lays the foundation for the subsequent secondary calibration. The secondary calibration is a process of further optimizing encoder performance in a broader system environment. It takes into account various factors under actual application conditions, such as mechanical installation errors and electrical noise interference, thereby achieving a higher level of position control accuracy.

[0037] S120. The encoder data is collected and processed through the servo motor 2 and the dragging platform 6, and a second set of calibration parameters is generated.

[0038] In this embodiment, the second set of calibration parameters refers to a set of data calculated based on a system-level error model after acquiring, processing, and analyzing the encoder's raw output data to compensate for system-level errors. This set of parameters aims to enable the encoder to provide high-precision position or speed information under various operating conditions through precise control and adjustment, thereby overcoming system-level error problems that cannot be eliminated during the initial calibration.

[0039] In one embodiment, step S120 described above may include steps S121 to S125.

[0040] S121. Mechanically connect the module under test and the servo motor 2 to the dragging platform 6, with their axes aligned and securely fixed.

[0041] In this embodiment, the module under test includes a motor and a main control board.

[0042] S122. Control the servo motor 2 to run at a stable speed and synchronously collect the raw output data of the encoder; S123. The original output data is processed using a linear fitting method. The module is moved to different speed points using servo motor 2. The range, variance or standard deviation at different speeds are evaluated, and the range, variance or standard deviation is ensured to be within the acceptable range. If at least one of the range, variance, or standard deviation is outside the acceptable range, step S122 is repeated.

[0043] S124. Calculate the second set of calibration parameters based on the system-level error model, and store the second set of calibration parameters in the non-volatile memory of the main controller.

[0044] In this embodiment, the module under test (including the motor and main control board) is first mechanically connected to the high-precision servo motor 2 on the dragging platform 6. It is ensured that the axes of both are aligned and securely fixed to avoid any unnecessary offset or vibration, thereby guaranteeing the accuracy of data acquisition.

[0045] Next, the servo motor 2 is controlled to run to a stable speed point, and the collection of the encoder's raw output data begins simultaneously. This stage requires the servo motor 2 to remain stable after reaching the specified speed in order to accurately obtain the encoder's performance under these conditions. This step may need to be repeated multiple times, testing at different speeds, to comprehensively evaluate the encoder's performance under various operating conditions.

[0046] Subsequently, as Figure 2 As shown, the encoder linear fitting curve is presented. The calibration data points are all discrete points. When the full range of data is collected, linear fitting is also required. L0 is the theoretical curve; L1 is the actual curve; A0 and B0 are theoretical sampling points; A1 and B1 are actual sampling points; X0 and X1 are the points to be calibrated. The previously collected raw output data is processed using a linear fitting method. This process involves comparing the difference between the actual collected data and the theoretical values ​​to calculate the corresponding calibration parameters. Furthermore, servo motor 2 is used to move the module to different speed points to evaluate the range, variance, or standard deviation of the speed values ​​measured at these different speeds, ensuring that all these statistical indicators are within acceptable ranges. If any indicator exceeds the preset range, the data acquisition process must be restarted until all accuracy requirements are met.

[0047] Based on the system-level error model, and using the data obtained in the previous step, a second set of calibration parameters is calculated to compensate for system-level errors. This set of parameters aims to adjust the encoder's output to more accurately reflect the actual situation. After calculation, this set of calibration parameters is immediately stored in the main controller's non-volatile memory, such as the microcontroller's internal Flash or external SPI Flash, for quick retrieval and application in subsequent use.

[0048] In this embodiment, the system-level error model refers to a mathematical or physical model established when analyzing and correcting the performance of a complex system (such as a module consisting of an encoder and a driver), taking into account the interactions between all components and their impact on the overall accuracy. For encoders, system-level errors not only originate from the encoder itself (e.g., inaccurate scale, installation deviation, etc.), but also include the influence of the motor, controller, and other external factors (e.g., temperature changes, mechanical wear, etc.) used with it.

[0049] First, raw encoder output data needs to be collected under different operating conditions (such as different speed points). These conditions should cover the actual usage scenarios of the encoder as much as possible to ensure that the collected data is representative. The collected data is then processed using linear fitting or other statistical methods to identify the difference between the actual output and the ideal output. In this process, statistical measures such as range, variance, or standard deviation may be calculated to quantify this difference.

[0050] An error model is constructed based on the results of data analysis. This model aims to describe how system-level errors vary with various factors (such as speed, load, etc.). For example, in the case of an encoder, system-level errors might be estimated by comparing the differences between theoretical and actual measurements, and how to compensate for these errors might be considered.

[0051] The calibration parameters used to compensate for the error are calculated based on the established error model. This step involves complex mathematical operations, such as solving systems of equations or optimization algorithms, to find the optimal combination of calibration parameters that minimizes the system error.

[0052] Finally, the calculated calibration parameters are applied to the system, and their effectiveness is verified experimentally. If the results do not meet expectations, the previous steps must be repeated for adjustments until the required accuracy is achieved.

[0053] The second set of calibration parameters is calculated based on a system-level error model through linear fitting of the encoder data. Specifically, the corresponding points on the theoretical and actual curves are first determined, and then the calibration value for each sampling point is calculated. Next, linear fitting is performed on discrete data points across the entire range to generate the final calibration parameters. These parameters are then stored in the main controller's non-volatile memory for real-time access and use in subsequent applications, thereby achieving high-precision position information acquisition.

[0054] The calculated calibration parameters are saved to memory according to certain rules (such as ascending order), and corresponding functions are designed to read and apply these parameters. For example, a specific read function, uint16 get_Encoder_CaliData(uint16 value), is provided to retrieve calibration data from a specific location in memory, ensuring that these calibration parameters can be applied in real time during normal device operation to improve the accuracy of motion control.

[0055] S130. When the device where the encoder is located is working normally, position information is provided by linear fitting by combining the first set of calibration parameters and the second set of calibration parameters.

[0056] In this embodiment, when the device containing the encoder is working normally, the first set of calibration parameters after the encoder has undergone initial calibration is read in real time, and then the second set of calibration parameters is read from its own Flash. The two are then linearly fitted to obtain the position information.

[0057] When the device starts up and enters normal operating mode, the system first reads the first set of calibration parameters previously saved from the encoder's non-volatile memory. These parameters are obtained during the self-calibration process performed after the encoder is installed. These parameters are mainly used to correct position or speed measurement errors caused by factors such as manufacturing errors and installation deviations of the encoder itself.

[0058] Next, the system reads the second set of calibration parameters from the Flash memory of the main controller (such as an STM32 microcontroller). These parameters are calculated based on a system-level error model after precise testing of the entire module (including the motor, encoder, and its control system). The second set of calibration parameters is used to compensate for additional errors caused by the interaction of the entire system, such as mechanical connection errors between the motor and encoder, and the effects of temperature changes.

[0059] Once the two sets of calibration parameters are obtained, the next step is to combine them. This typically involves a series of mathematical processing steps on the raw signal, including but not limited to linear interpolation, polynomial fitting, or other forms of data smoothing techniques. For each sampling point, the actual measured data is adjusted using the first and second sets of calibration parameters based on its corresponding theoretical value (the ideal output). For example, if the actual value at a point is Encoder(X1), the corrected value might be Encoder(X1) + Calib(X), where Calib(X) is a correction factor determined by both sets of calibration parameters. This process aims to minimize the impact of all known error sources in the system, thereby improving the accuracy and reliability of the final location information.

[0060] After completing the above steps, the system can output high-precision position information after dual calibration. This means that both static positioning and dynamic tracking tasks can be performed with higher accuracy. Ensuring stable and accurate position feedback throughout the entire working range, regardless of speed variations, is crucial for applications requiring highly precise control.

[0061] In this way, this embodiment not only solves the problem that built-in calibration cannot eliminate system-level errors, but also greatly improves the flexibility and adaptability of the entire system, enabling it to maintain a high performance level even in different working environments or conditions.

[0062] In this embodiment, a module consisting of an STM32 microcontroller as the main control chip, a Magnum MT6826S encoder, and a servo motor 2, along with a high-precision servo motor 2 and a dragging platform 6, constitutes the hardware used in this method.

[0063] After ensuring the encoder is securely installed, perform the encoder self-calibration process according to the manufacturer's instructions. This step aims to eliminate manufacturing defects in the encoder itself and any deviations that may have occurred during installation.

[0064] After the initial calibration is completed, the driver, encoder and servo motor 2 are assembled together to form a module, and it is fixed together with the high-precision servo motor 2 on the towing platform 6, and then the secondary calibration is started.

[0065] First, the high-precision servo motor 2 is controlled to operate at a specific speed mode (e.g., 800 RPM). After its speed stabilizes, a secondary verification command is sent to the module via CAN communication. Upon receiving the command, the module begins searching for the encoder zero point and collects encoder data at fixed time intervals from that point, temporarily storing it in the microcontroller's internal RAM. After data acquisition, the collected data is initially checked to determine if the direction of data change is reasonable, thereby confirming the validity of the data or identifying whether there is a fault in the encoder. Next, the compensation value is calculated based on the difference between the theoretical value and the actual sampled value. For any two points A and B, the calibration values ​​are: Calib(A) = Encoder(A0) - Encoder(A1); Calib(B) = Encoder(B0) - Encoder(B1); When processing discrete data points, linear fitting is required. Suppose a data point X is collected between A and B, and its actual sampled value is Encoder(X1). Then the calibration value of point X is: Calib(X) = ; The calibrated value of point X is: Encoder(X0) = Encoder(X1) + Calib(X); After calculating the calibration values, these data need to be validated to assess whether they meet specifications and effectively improve performance. Error analysis methods include range analysis and variance / standard deviation analysis.

[0066] The module is dragged to different speed points (such as 500 RPM, 1000 RPM, and 2000 RPM) using the dragging platform 6, and an error analysis command is sent to the module after it stabilizes at each speed point.

[0067] Range analysis: Velocity data is collected every 50ms, and the range of the velocity curve is calculated within 5 seconds. : For high-precision modules, the requirements are... <0.03 Speed.

[0068] Analysis of variance or standard deviation: First, collect N sets of data (N>50), then calculate the variance ERRσ using the following formula: Variance ERRσ is the mathematical expectation that measures the “unevenness” or “fluctuation” of a set of data, quantifying the degree to which data or random variables deviate from their mean.

[0069] Standard deviation It is the square root of the variance, and is the most commonly used and intuitive indicator for describing volatility. Used to describe volatility: ; For high-precision modules, a standard deviation is required. <0.01 Speed.

[0070] If the range or standard deviation does not meet the requirements, step S120 needs to be repeated until the conditions are met.

[0071] The parameters determined after error analysis should be saved to the MCU's Flash memory for later use. Parameter saving follows an ascending order principle, that is, saving sequentially starting from the encoder's zero point. Taking a 16-bit encoder as an example, the function for reading any encoder calibration value is as follows: uint16 get_Encoder_CaliData(uint16 value){ return ((uint16) (uint8 )(ADDR_ENCONDER_START + value) + value); }

[0072] The above is a detailed explanation of the implementation steps based on the STM32 microcontroller driver, the Magnum MT6826S encoder, and the servo motor module 2, covering the entire process from initial calibration to secondary calibration and finally parameter saving and reading.

[0073] The method in this embodiment, through implementing a secondary calibration procedure, effectively compensates for systematic errors throughout the entire signal chain from the encoder to the processor chip, including mechanical mounting and circuit-related errors. This system-level error compensation mechanism significantly improves the overall system accuracy.

[0074] In this embodiment, the calibration parameters are stored in the main controller, which not only facilitates parameter modification and updates but also supports flexible adjustments based on the needs of different application scenarios. Furthermore, this design even allows the device to perform online calibration and parameter optimization during operation, further enhancing its adaptability.

[0075] By performing joint calibration of the entire system, the method in this embodiment can eliminate individual differences between different devices, ensuring that the performance of each device remains highly consistent even under large-scale production conditions. This is of great significance for ensuring product quality and improving user experience.

[0076] The method described in this embodiment is designed to allow the use of encoder components with slightly lower performance but more economical costs, while meeting high accuracy requirements through subsequent secondary calibration. This method effectively reduces the overall cost of the system without sacrificing the performance quality of the final product.

[0077] In summary, the method of this embodiment, through its unique design concept and technical implementation, not only improves product performance but also takes into account factors such as cost control and application flexibility, demonstrating the important value of technological innovation in promoting industry development.

[0078] The aforementioned secondary calibration method for encoders calculates a first set of calibration parameters after encoder installation using an internal self-calibration program to correct initial errors. Then, servo motor 2 and the dragging platform 6 collect encoder data during actual operation to generate a second set of calibration parameters to compensate for system-level errors generated during operation. When the equipment is operating normally, these two sets of parameters are combined and linear fitting is used to provide precise position information. This method not only effectively solves the system-level error problem that built-in calibration cannot eliminate, but also significantly improves the system's flexibility and adaptability because the calibration parameters can be flexibly adjusted and updated in the main controller, ultimately achieving a significant improvement in encoder accuracy.

[0079] In one embodiment, a secondary calibration system for an encoder is also provided, which uses the aforementioned secondary calibration method for an encoder.

[0080] Please see Figure 3 The aforementioned encoder secondary calibration system includes: a module under test, a servo motor 2, and a dragging platform 6; the module under test and the servo motor 2 are respectively connected to the dragging platform 6.

[0081] Please see Figure 3 The aforementioned encoder secondary calibration system also includes a speed detection device, which is connected to both the module under test and the servo motor 2.

[0082] Please see Figure 3 The aforementioned encoder secondary calibration system also includes: a leveling device 5 and a base 4. The leveling device 5 is connected to a dragging platform 6. There are two dragging platforms 6, which are connected to the base 4.

[0083] The module under test (DUT): This part includes the motor and a processor chip with built-in Flash memory. The processor chip is configured to perform all steps of the secondary calibration method, including data acquisition, calculation, storage, and application of the second calibration parameters. In this way, the DUT can not only achieve accurate calibration of its own position information, but also flexibly adjust the calibration parameters according to the actual working environment.

[0084] Servo Motor 2: A high-precision servo motor 2 is used to provide high-precision position / speed control. Servo Motor 2 is one of the key components of the entire system. It is connected to the module under test on the towing platform 6 to ensure that the two can operate synchronously, thereby achieving accurate data acquisition and processing.

[0085] The dragging platform 6 consists of two dragging platforms 6, each equipped with a leveling device 5, and ultimately fixed to a common base 4. The main function of the dragging platform 6 is to drive the module under test (DUT) to operate at a stable speed point, while ensuring synchronous movement between the servo motor 2 and the DUT. This design helps eliminate errors caused by mechanical structures and improves calibration accuracy.

[0086] Speed ​​detection device: As an additional component, the speed detection device is connected to both the module under test and servo motor 2. Its function is to monitor the operating speed of both in real time, ensuring that they remain consistent throughout the calibration process. This step is crucial for obtaining accurate calibration parameters.

[0087] Leveling device 5 and base 4: Leveling device 5 is used to ensure that the drag platform 6 is in an ideal level state, avoiding any tilting or unevenness that may affect the calibration results. All components are mounted on a sturdy base 4 to ensure the stability of the entire system.

[0088] First, after the encoder is installed, the first set of calibration parameters is calculated by the internal self-calibration program and stored in the encoder's first memory. Then, using the servo motor 2 and the dragging platform 6, the module under test is run at a stable speed. The speed detection device monitors and records the relevant data, thereby generating the second set of calibration parameters. Finally, when the equipment is working normally, the first and second sets of calibration parameters are combined and precise position information is provided through linear fitting.

[0089] This design not only solves the problem that traditional built-in calibration cannot eliminate system-level errors, but also greatly improves the system's flexibility and adaptability, enabling the encoder to maintain high accuracy in various complex operating environments.

[0090] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A secondary calibration method for an encoder, characterized in that, include: After the encoder is installed, the first set of calibration parameters is calculated through the internal self-calibration program; The encoder data is collected and processed via a servo motor and a drag platform, and a second set of calibration parameters is generated. When the device containing the encoder is working normally, position information is provided by linear fitting by combining the first set of calibration parameters and the second set of calibration parameters. After the encoder is installed, the first set of calibration parameters is calculated through an internal self-calibration program, including: After the encoder is installed, the motor is controlled by the sensorless controller to drive the encoder to rotate at a constant speed and trigger the encoder's internal self-calibration program to perform the initial calibration. After the initial calibration is completed, the encoder calculates the first set of calibration parameters and saves the first set of calibration parameters in the encoder's non-volatile memory; The process involves collecting and processing encoder data via a servo motor and a dragging platform, and generating a second set of calibration parameters, including: The module under test and the servo motor are mechanically connected to the drag platform, with their axes aligned and securely fixed. Control the servo motor to run at a stable speed, and synchronously collect the raw output data of the encoder; The original output data is processed using a linear fitting method. A servo motor is used to move the module to different speed points to evaluate the range, variance, or standard deviation at different speeds and ensure that the range, variance, or standard deviation is within an acceptable range. The second set of calibration parameters is calculated based on the system-level error model and stored in the non-volatile memory of the main controller. The module under test includes a motor and a main control board; When the device containing the encoder is operating normally, the position information is provided through linear fitting by combining the first set of calibration parameters and the second set of calibration parameters, including: When the device containing the encoder is working normally, the first set of calibration parameters after the encoder has undergone initial calibration is read in real time, and then the second set of calibration parameters is read from its own Flash. The two are then linearly fitted to obtain the position information.

2. The encoder secondary calibration method according to claim 1, characterized in that, The process of processing the original output data using a linear fitting method, moving the module to different speed points using a servo motor, evaluating the range, variance, or standard deviation at different speeds, and ensuring that the range, variance, or standard deviation is within an acceptable range, further includes: If at least one of the range, variance, or standard deviation is outside the acceptable range, the control servo motor is restarted to run at a stable speed, and the original output data of the encoder is collected synchronously.

3. A secondary calibration system for an encoder, characterized in that, The system uses a secondary calibration method for an encoder as described in any one of claims 1 to 2.

4. The encoder secondary calibration system according to claim 3, characterized in that, include: The module under test, the servo motor, and the dragging platform; The module under test and the servo motor are respectively connected to the dragging platform.

5. The encoder secondary calibration system according to claim 4, characterized in that, Also includes: A speed detection device is connected to both the module under test and the servo motor.

6. The encoder secondary calibration system according to claim 5, characterized in that, Also includes: The leveling device and the base are provided. The leveling device is connected to the two towing platforms, which are connected to the base.

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