A tachometer calibration device

Abstract

The present invention discloses a tachometer calibration device, which relates to the field of tachometer calibration. The tachometer calibration device includes a camera unit, a rotation speed detection unit, a control and processing unit, and a calibration unit; the camera unit is used to photograph the tachometer of the target motor to obtain an image of the indicated value of the tachometer; the rotation speed detection unit is used to detect the rotation speed of the target motor and generate a rotation speed detection signal; the control and processing unit is respectively connected to the camera unit and the rotation speed detection unit, and is used to determine the indicated rotation speed value displayed by the tachometer according to the image of the indicated value, determine the rotation speed detection value of the target motor according to the rotation speed detection signal, determine that the tachometer needs calibration processing according to the rotation speed detection value and the indicated rotation speed value, and generate a calibration processing signal; the calibration unit is used to calibrate the tachometer according to the calibration processing signal. The present invention can accurately measure and calibrate the motor tachometer automatically, ensure the accuracy of its reading, reduce the error of manual operation, and improve the reliability of the calibration accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of tachometer calibration, and particularly to a tachometer calibration device. Background Art

[0002] The tachometer of an electric motor is an important monitoring tool for measuring and displaying the rotational speed of the electric motor in real time. It is crucial for ensuring that mechanical equipment operates according to predetermined parameters, helping operators monitor the working state of the electric motor and promptly adjust or handle potential problems. Through the tachometer, equipment damage caused by abnormal speed can be prevented, ensuring the continuity and efficiency of the production line. Tachometer calibration is carried out to ensure the accuracy and reliability of its measurement data. Due to environmental changes, equipment aging or other factors, the readings of the tachometer may deviate. Regular calibration can eliminate these errors and ensure that the electric motor operates in the best state.

[0003] In related technologies, the tachometer calibration method usually involves connecting the electric motor tachometer to a calibration device. By comparing the reading displayed on the tachometer with the known rotational speed provided by the calibration device, the operator can adjust the tachometer to make its reading consistent with the standard rotational speed.

[0004] However, this manual operation calibration method relies heavily on the experience and judgment of the operator, and human errors increase the uncertainty in the calibration process, resulting in unreliable calibration accuracy. Summary of the Invention

[0005] Aiming at the above technical problems and deficiencies, the purpose of the present invention is to provide a tachometer calibration device that can accurately measure and calibrate the electric motor tachometer automatically, ensure the accuracy of its readings, reduce the errors of manual operation, and improve the reliability of calibration accuracy.

[0006] To achieve the above purpose, the present invention provides a tachometer calibration device, including a camera unit, a rotational speed detection unit, a control and processing unit, and a calibration unit; the camera unit is used to photograph the tachometer of the target electric motor to obtain an image of the displayed value of the tachometer; the rotational speed detection unit is used to detect the rotational speed of the target electric motor and generate a rotational speed detection signal; the control and processing unit is respectively connected to the camera unit and the rotational speed detection unit, and is used to determine the displayed rotational speed value displayed on the tachometer according to the image of the displayed value, determine the rotational speed detection value of the target electric motor according to the rotational speed detection signal, determine that the tachometer needs calibration processing according to the rotational speed detection value and the displayed rotational speed value, and generate a calibration processing signal; the calibration unit is respectively connected to the tachometer and the control and processing unit, and is used to calibrate the tachometer according to the calibration processing signal.

[0007] The present invention achieves the high efficiency and accuracy of tachometer calibration through precise automated processes. First, the imaging unit captures real-time images of the tachometer, and uses image recognition technology to extract the indicated speed value. This process avoids human reading errors and ensures the objectivity and consistency of speed value reading. Secondly, the speed detection unit uses a high-precision sensor to directly measure the actual speed of the motor, generating an accurate speed detection signal, thereby providing a reliable reference benchmark. The control processing unit, as the core, compares and analyzes the indicated speed value obtained by the imaging unit with the actual speed value measured by the speed detection unit, identifies the deviation between the two, and calculates the necessary calibration parameters; based on these calibration parameters, the control processing unit generates a calibration processing signal to drive the calibration unit to automatically and precisely adjust the tachometer. This automated calibration process not only reduces errors caused by human factors, but also improves the speed and efficiency of calibration. Moreover, through real-time monitoring and continuous calibration, this device can ensure that the tachometer can provide accurate speed readings under various working conditions, thereby improving the reliability and stability of the entire system.

[0008] In some embodiments, the control processing unit is specifically configured to call a preset tachometer display value recognition model to perform recognition processing on the display value image to obtain the indicated speed value.

[0009] Adopting the technical solution of the above embodiment, by introducing a preset tachometer display value recognition model, the recognition accuracy and processing speed of the tachometer display value image are significantly improved. This model is specifically optimized for the display characteristics of the tachometer and can efficiently extract speed information from the image. By using a trained machine learning model, this device can adapt to different display value representation methods, whether it is pointer type or digital type, and can accurately identify them. In addition, the preset nature of the model means that it can be quickly deployed, reducing on-site debugging time and improving the overall calibration efficiency.

[0010] In some embodiments, the training process of the tachometer display value recognition model includes: obtaining a plurality of display value sample images, where the display value sample images include pointer type display value sample images and digital type display value sample images; marking the true values of the pointer type display value sample images and the digital type display value sample images in the display value sample images to obtain a training data set; training a selected machine learning model through the training data set to obtain a trained tachometer display value recognition model.

[0011] Adopting the technical solution of the above embodiments, a training process for the tachometer display value recognition model is provided. By using diverse sample images, including pointer-type and digital tachometers, as well as images under different lighting and stain conditions, the generalization ability and robustness of the model are enhanced. This training method ensures that the model can still accurately recognize the readings of the tachometer when facing the variable conditions in the actual environment. In this way, the tachometer calibration device can provide more reliable and consistent calibration results, reducing errors caused by environmental factors.

[0012] In some embodiments, the sample images of the displayed values also include tachometer images under different lighting environments and tachometer images affected by stains.

[0013] Adopting the technical solution of the above embodiments, by including tachometer images under different lighting environments and affected by stains as samples, the practicability and accuracy of the calibration device are further improved. This comprehensive consideration of samples ensures that the device can accurately perform the calibration task even under extreme or unfavorable conditions. This not only improves the accuracy of the calibration results but also expands the application range of the device, enabling it to work reliably in various industrial environments.

[0014] In some embodiments, the tachometer calibration device further includes a reminder unit. The reminder unit is connected to the control and processing unit. The control and processing unit is used to determine that the surface stain occlusion range of the tachometer exceeds the set standard range according to the displayed value image and generate a cleaning prompt instruction. The reminder unit is used to issue a physical reminder signal that the tachometer needs to be cleaned according to the cleaning prompt instruction.

[0015] Adopting the technical solution of the above embodiments, by integrating the reminder unit, the user interaction function is increased, and the operation convenience and the intelligence of the device are improved. When the control and processing unit detects that the surface stain of the tachometer exceeds the preset standard, the reminder unit will actively notify the user to clean, thus avoiding recognition errors and calibration failures caused by stains. This active reminder mechanism ensures the smooth progress of the calibration process and reduces the risk of repeated calibration due to unclear displayed value images.

[0016] In some embodiments, the tachometer calibration device further includes a signal processing unit. The signal processing unit is connected between the rotation speed detection unit and the control and processing unit. The signal processing unit is used to perform enhancement processing on the rotation speed detection signal.

[0017] Adopting the technical solution of the above embodiment, by adding a signal processing unit between the rotation speed detection unit and the control processing unit, the quality of the rotation speed detection signal is improved. The signal processing unit performs enhancement processing such as filtering and amplifying on the original rotation speed signal, ensuring that even under conditions of more noise or weaker signals, the control processing unit can receive clear and accurate signals. This not only improves the accuracy of rotation speed detection but also enhances the reliability and stability of the entire calibration device.

[0018] In some embodiments, the calibration unit is further configured to return a calibration completion signal to the control processing unit after calibration is completed, and the control processing unit is further configured to generate a calibration record report for the tachometer according to the calibration completion signal.

[0019] Adopting the technical solution of the above embodiment, by integrating the function of generating a calibration record report in the control processing unit and combining the feedback mechanism of the calibration unit, the full automation of the calibration process and the automated management of records are realized. After calibration is completed, the calibration unit sends a calibration completion signal to the control processing unit, and the control processing unit generates a detailed calibration record report accordingly. This automated record management not only improves the calibration efficiency but also facilitates subsequent data analysis and quality control.

[0020] In some embodiments, the tachometer calibration device further includes a wireless communication unit, which is connected to the control processing unit and is used to send the calibration record report to the user terminal of the staff.

[0021] Adopting the technical solution of the above embodiment, by integrating a wireless communication unit in the tachometer calibration device, the wireless transmission of the calibration record report is realized, greatly improving the convenience of the staff and the accessibility of the calibration data. The staff can remotely receive the calibration record report through the user terminal device and monitor the calibration status and results in real time. This wireless communication function is particularly suitable for large factories or multi-region facilities, improving the flexibility and response speed of the calibration work.

[0022] In some embodiments, the control processing unit is connected to the motor control unit of the target motor and is used to send a rotation speed control instruction to the motor control unit so that the motor control unit controls the rotation speed of the target motor according to the rotation speed control instruction.

[0023] Adopting the technical solution of the above embodiment, by connecting the control processing unit to the motor control unit of the target motor, the direct control of the rotation speed of the target motor is realized. This direct control mechanism allows the calibration device to adjust the motor rotation speed as needed for precise calibration. This not only improves the calibration accuracy but also makes the calibration process more flexible and efficient, especially in cases where calibration is required at a specific rotation speed.

[0024] In some embodiments, the tachometer calibration device further includes a metal housing, and the control processing unit is disposed in the metal housing.

[0025] Adopting the technical solution of the above embodiment, by designing a metal housing for the tachometer calibration device, additional physical protection and environmental isolation are provided. The metal housing not only protects the internal components from mechanical damages such as impacts and drops, but also helps to shield external electromagnetic interference, ensuring the accuracy of signal processing and data calculation. In addition, the metal housing has corrosion-resistant characteristics, can resist the influence of harsh environments, improves the durability and reliability of the device, and enables it to adapt to the challenges of various industrial environments.

[0026] One or more technical solutions provided by the present invention have at least the following technical effects or advantages:

[0027] 1. The tachometer calibration device of the present invention realizes the full automation of the tachometer calibration process by integrating a camera unit, a tachometer detection unit, a control processing unit, a calibration unit, and a wireless communication unit. This automation not only reduces human operation errors and labor intensity, but also improves the efficiency and accuracy of calibration. By automatically acquiring the image of the tachometer display value, automatically detecting the actual speed of the motor, automatically performing image recognition, automatically comparing and analyzing data, automatically executing the calibration operation, and automatically generating and sending the calibration record report, the device significantly improves the intelligent level of motor control and maintenance in industrial environments.

[0028] 2. Through the high-precision tachometer detection unit and advanced image recognition technology, accurate measurement and calibration of the motor speed are ensured. The tachometer detection unit uses a non-contact sensor to directly measure the motor speed and generates an accurate tachometer detection signal; the control processing unit calls a well-trained tachometer display value recognition model to accurately identify the speed value in the image. In addition, the enhanced processing of the signal processing unit further improves the signal quality. The combination of these technologies enables the device to provide high-precision tachometer measurement and calibration results, meeting the strict requirements for precision in industrial applications.

[0029] 3. It has environmental adaptability and friendly user interaction. The present invention can process images under different lighting conditions and can accurately identify the readings of the tachometer even when it is blocked by stains. In addition, through the integration of the reminder unit, the device can actively remind the user to clean the tachometer when it detects stain blocking, ensuring the smooth progress of the calibration process. The addition of the wireless communication unit enables the calibration record report to be remotely transmitted to the user side, improving the convenience of the staff. The protection of the metal housing further improves the durability and reliability of the device in harsh industrial environments. These designs enable the tachometer calibration device to work stably in various environments and at the same time provide a convenient operation experience for users. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments in accordance with the present invention, and are used together with the specification to explain the principles of the present invention. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. In the drawings:

[0031] Figure 1 is a schematic structural organization diagram of a tachometer calibration device according to an embodiment of the present invention;

[0032] Figure 2 is a schematic architecture diagram of a tachometer calibration device according to an embodiment of the present invention.

[0033] Explanation of reference numerals:

[0034] 1. Camera unit; 2. Rotation speed detection unit; 3. Control processing unit; 4. Calibration unit; 5. Reminder unit; 6. Signal processing unit; 7. Wireless communication unit. Detailed implementation manners

[0035] The terms used in the following embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention, the singular forms "a", "an", "the above", "the", and "this" are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used in the present invention refers to any or all possible combinations including one or more of the listed items.

[0036] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0037] It should also be noted that, unless otherwise clearly specified and defined, in the embodiments of the present invention, terms such as "set" and "connect" should be understood in a broad sense. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components; it can be a wired communication connection or a wireless communication connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following is a specific description of the embodiments of the present invention.

[0038] An embodiment of the present invention provides a tachometer calibration device, as Figure 1 shown, including a camera unit 1, a speed detection unit 2, a control processing unit 3, and a calibration unit 4.

[0039] The camera unit 1 is used to photograph the tachometer of the target motor to obtain an image of the displayed value of the tachometer.

[0040] Among them, the camera unit 1 can be composed of a high-resolution industrial camera, an adapter lens, a stable bracket, and an image acquisition card. The camera unit 1 is designed to stably capture images of the tachometer of the target motor under various environmental conditions. The industrial camera has high sensitivity and fast capture capabilities and can set different exposure times and shutter speeds to adapt to different lighting environments. The adapter lens ensures image clarity and focusing accuracy and can be adjusted manually or automatically to obtain the best image quality. The camera unit 1 is mounted on a stable bracket that allows precise adjustment of the camera's angle and distance to ensure that the displayed value of the tachometer is at the center of the camera's field of view. The image acquisition card is responsible for transmitting the images captured by the camera to the control processing unit 3 for further processing and analysis. Through these designs, the camera unit 1 can accurately capture the image of the displayed value of the tachometer, providing reliable visual data input for the tachometer calibration device.

[0041] The speed detection unit 2 is used to detect the speed of the target motor and generate a speed detection signal.

[0042] Among them, the speed detection unit 2 can include one or more non-contact speed sensors, such as photoelectric sensors, Hall effect sensors, or magnetoelectric sensors. These speed sensors use physical effects to detect the speed on the motor shaft. For example, a photoelectric sensor works by emitting light and detecting the light reflected by a rotating part of the motor (such as a disk with a reflective mark); a Hall effect sensor uses the Hall effect to detect the magnetic field change caused by the rotating part. The sensors are installed near the motor to ensure the correct alignment of their detection heads with the rotating parts to accurately capture speed information. The original signal output by the speed sensor is usually a pulse sequence, and each pulse corresponds to one rotation period of the motor shaft. The electronic processing system inside the speed detection unit 2 counts and times these pulses to calculate the real-time speed of the motor.

[0043] Then, the speed detection unit 2 converts the calculation result into a corresponding speed detection signal, which can be an analog voltage, a digital value, or serial data, and transmits it to the control processing unit 3 for comparison and analysis to determine whether the tachometer needs to be calibrated. This high-precision speed detection method provides a reliable reference benchmark, ensuring the accuracy and reliability of the calibration process.

[0044] The control processing unit 3 is respectively connected to the imaging unit 1 and the rotational speed detection unit 2, and is used to determine the indicated rotational speed value displayed by the tachometer according to the indicated value image, determine the rotational speed detection value of the target motor according to the rotational speed detection signal, determine that the tachometer needs calibration processing according to the rotational speed detection value and the indicated rotational speed value, and generate a calibration processing signal.

[0045] Specifically, the control processing unit 3 is the center of the tachometer calibration device and is responsible for processing and analyzing data from the imaging unit 1 and the rotational speed detection unit 2. First, the control processing unit 3 receives the indicated value image of the tachometer captured by the imaging unit 1, and pre-processes the image using built-in image processing algorithms, such as denoising and enhancing contrast, to improve the recognition accuracy of the indicated value. Then, through optical character recognition (OCR) technology, the rotational speed value in the image is converted into a digital signal, thereby determining the indicated rotational speed value displayed by the tachometer.

[0046] Next, the control processing unit 3 receives the pulsed rotational speed detection signal generated by the rotational speed detection unit 2, and these rotational speed detection signals are proportional to the physical rotational speed of the target motor. By counting the number of pulses within a certain time and combining the specification parameters of the sensor, the control processing unit 3 calculates the actual rotational speed of the motor and generates a rotational speed detection value.

[0047] Finally, the control processing unit 3 compares the indicated rotational speed value and the rotational speed detection value. If there is a significant difference between the two, it indicates that the reading of the tachometer is inaccurate and calibration is required.

[0048] Specifically, the control processing unit 3 compares the error value between the indicated rotational speed value and the rotational speed detection value, combines the performance parameters of the tachometer and historical calibration data, and uses a mathematical model and a calibration strategy to calculate the amount that needs to be adjusted, that is, the calibration parameter.

[0049] For example, the mathematical model can adopt a linear regression model to determine the linear relationship between the indicated rotational speed value and the actual rotational speed detection value, thereby calculating the calibration parameter. If the error shows a non-linear characteristic, a polynomial regression or other non-linear model may be used to more accurately describe this relationship. In addition, the least squares method can also be used to find the best fit line by minimizing the sum of the squares of the errors, thereby determining the calibration parameter.

[0050] The calibration strategy involves how to apply these mathematical models to perform effective calibration. It may include selecting key calibration points that can represent the performance of the entire range of the tachometer; determining the calibration sequence, whether to calibrate the high or low end of the range first, or using a step-by-step calibration method to gradually approach the ideal value; and calculating the calibration step value, i.e., the amount of adjustment each time, to avoid over-adjustment or under-adjustment. The calibration strategy may also include an iterative process, in which the control processing unit 3 updates the model parameters according to the results after each calibration until the preset accuracy requirement is met. In addition, an adaptive algorithm can be introduced to dynamically adjust the calibration strategy based on the real-time feedback of the tachometer response to improve the accuracy and efficiency of calibration.

[0051] Calibration parameters may include but are not limited to: the magnitude of adjustment (such as the rotational speed value to be increased or decreased), the step size of adjustment, the rate of adjustment, and in some cases, it may also be necessary to compensate for environmental factors (such as the influence of temperature and humidity on the tachometer reading). The calculated calibration parameters are encapsulated into a calibration processing signal, which clearly indicates in a certain format (possibly digital quantity, analog voltage, or serial data) how the calibration unit 4 should adjust the tachometer to eliminate errors.

[0052] The calibration processing signal is then transmitted to the calibration unit 4, which performs the actual calibration actions according to these signals, such as changing the mechanical pointer position of the tachometer by finely tuning the motor-driven adjustment mechanism, or correcting the counter threshold of the tachometer through electronic adjustment.

[0053] Throughout the process, the control processing unit 3 may also monitor the calibration results in real time to ensure that the calibration operation meets the expected accuracy. If the calibration results do not meet the expectations, the control processing unit 3 will continue to adjust the calibration parameters based on the feedback until the reading of the tachometer is consistent with the actual rotational speed.

[0054] These calibration processing signals will be sent to the calibration unit 4 to guide it to perform precise calibration operations on the tachometer to eliminate errors and ensure that the reading of the tachometer is consistent with the actual rotational speed of the motor. The entire process has a high degree of automation, reducing human intervention and improving the efficiency and accuracy of calibration.

[0055] In this embodiment, the control processing unit can adopt various types of electronic devices, including but not limited to microcontrollers (MCUs), digital signal processors (DSPs), microprocessors (MPUs), systems on a chip (SoCs), programmable logic controllers (PLCs), single-board computers (SBCs), embedded computer modules, field-programmable gate arrays (FPGAs), and application-specific integrated circuits (ASICs). The selection of these devices depends on the required processing power, power consumption, cost-effectiveness, software support, and specific application requirements. For example, for resource-constrained and cost-effective scenarios, an MCU may be selected; while for applications that require running complex algorithms and processing large amounts of data, an MPU or SBC may be chosen.

[0056] The calibration unit 4 is respectively connected to the tachometer and the control processing unit 3, and is used to calibrate the tachometer according to the calibration processing signal.

[0057] Among them, the calibration unit 4 is the part responsible for implementing the calibration operation in the tachometer calibration device. It usually consists of a precision fine-tuning mechanism and an actuator. When the control processing unit 3 determines that the tachometer needs to be calibrated, it sends detailed calibration processing signals to the calibration unit 4. These calibration processing signals contain the specific parameters and adjustment amounts required for calibration. These signals can also include the specific type of calibration, such as whether it is an adjustment for mechanical deviation or a correction for electronic display, as well as the amplitude of the adjustment, that is, the specific value or range that needs to be changed.

[0058] After receiving these signals, the calibration unit 4 first performs signal parsing to clarify the specific calibration requirements. After the parsing is completed, the fine-tuning mechanism starts to perform the calibration task. The fine-tuning mechanism may include one or more micro-motors, which drive the adjustment screw through precise control, thereby finely adjusting the mechanical components of the tachometer, such as the gear or pointer position. This mechanical adjustment can very precisely eliminate mechanical deviations and ensure the correct alignment of the pointer or reading.

[0059] At the same time, the calibration unit 4 may also use piezoelectric ceramic elements for fine-tuning. This technology is based on the piezoelectric effect, that is, by applying a voltage, the ceramic element generates a small deformation, thereby achieving fine adjustment of the tachometer reading. This adjustment method is particularly suitable for digital tachometers and can precisely correct electronic display deviations.

[0060] Whether it is through the adjustment screw driven by a micro-motor or piezoelectric ceramic elements, the calibration unit 4 can achieve precise adjustment of the tachometer, ensuring that its reading is consistent with the actual speed of the motor, thus meeting the requirements of high-precision calibration.

[0061] During the adjustment process, the calibration unit 4 may monitor the output of the tachometer in real time to ensure that the adjustment achieves the desired effect. If necessary, it can also perform multiple fine-tuning and inspections to ensure that the tachometer reading accurately matches the actual rotational speed of the motor. Once the calibration is complete and the displayed value of the tachometer is consistent with the actual rotational speed value provided by the control processing unit 3, the calibration unit 4 will stop the adjustment and may send a confirmation signal back to the control processing unit 3 indicating that the calibration process has been successfully completed.

[0062] This automated calibration process ensures the accuracy and repeatability of the operation, greatly improving the efficiency and accuracy of calibration.

[0063] The tachometer calibration device of the present invention achieves the high efficiency and accuracy of tachometer calibration through an accurate automated process. First, the imaging unit 1 captures real-time images of the tachometer and uses image recognition technology to extract the displayed rotational speed value. This process avoids human reading errors and ensures the objectivity and consistency of rotational speed value reading. Second, the rotational speed detection unit 2 uses a high-precision sensor to directly measure the actual rotational speed of the motor and generates an accurate rotational speed detection signal, thereby providing a reliable reference benchmark. The control processing unit 3, as the core, compares and analyzes the displayed rotational speed value obtained by the imaging unit 1 with the actual rotational speed value measured by the rotational speed detection unit 2, identifies the deviation between the two, and calculates the necessary calibration parameters; based on these calibration parameters, the control processing unit 3 generates a calibration processing signal to drive the calibration unit 4 to automatically adjust the tachometer precisely. This automated calibration process not only reduces errors caused by human factors but also improves the speed and efficiency of calibration. Moreover, through real-time monitoring and continuous calibration, this device can ensure that the tachometer provides accurate rotational speed readings under various working conditions, thereby improving the reliability and stability of the entire system.

[0064] In some embodiments, the control processing unit 3 is specifically configured to call a preset tachometer displayed value recognition model to perform recognition processing on the displayed value image to obtain the displayed rotational speed value.

[0065] Among them, the tachometer displayed value recognition model is usually constructed based on machine vision and image processing technologies. This model is specifically designed to accurately extract the displayed rotational speed value from the tachometer image captured by the imaging unit 1.

[0066] For a pointer-type tachometer, the tachometer displayed value recognition model performs image preprocessing steps such as grayscale conversion and filtering denoising to clearly identify the pointer and scale of the tachometer. Then, it uses edge detection technology to determine the precise position of the pointer and determines the rotational speed value based on the relative position of the pointer and the scale.

[0067] For a digital tachometer, the model may use optical character recognition (OCR) technology to learn the features of different digits through a training dataset for highly accurate recognition.

[0068] In addition, the tachometer display value recognition model may also include a calibration mechanism to handle distortions or tilts in the image and ensure the robustness of the recognition process. The performance of the model is improved through continuous training and optimization to adapt to different tachometer types, sizes, and environmental conditions. Finally, the model converts the display value in the image into a digital format for further analysis and calibration by the control processing unit 3.

[0069] Specifically, the training process of the tachometer display value recognition model includes:

[0070] First, obtain multiple sample images of the display values, which include sample images of pointer-type display values and digital-type display values.

[0071] Specifically, image data can be collected from various pointer-type and digital tachometers. To ensure that the model can handle various different display scenarios, these images should be captured under various environmental conditions, including different lighting, angles, backgrounds, and tachometer specifications. A professional camera device can be used to aim at the tachometer and record images at different speeds of the motor operation to ensure that the sample images can cover the full range of the tachometer.

[0072] Then, mark the true values of the pointer-type display value sample images and the digital-type display value sample images in the sample images of the display values to obtain a training dataset.

[0073] Among them, for the pointer-type display value sample images, the pointer position of the tachometer can be identified and marked by experts and mapped to the specific rotational speed value; for the digital-type display value sample images, each digit displayed on the tachometer needs to be identified and these digits are concatenated into the actual rotational speed value.

[0074] Finally, train the selected machine learning model through the training dataset to obtain a trained tachometer display value recognition model.

[0075] Among them, for the digital-type display value sample images, a convolutional neural network (CNN) may be used to recognize and classify the digits in the image; for the pointer-type display value sample images, a regression model may be used to predict the rotational speed value pointed by the pointer. During the training process, the model will continuously adjust its own parameters to reduce the difference between the predicted value and the actual marked value. Through repeated training and verification, the finally obtained model will be able to accurately recognize the display value of the tachometer on new and unseen images.

[0076] In this embodiment, a selected machine learning model is trained using a training dataset. This process includes adjusting model parameters, using techniques such as cross-validation to evaluate the model's performance, and selecting the best model structure and hyperparameters.

[0077] After that, it is also necessary to test the accuracy and robustness of the model on an independent validation dataset. The model is adjusted and optimized according to the test results to improve its prediction performance on unknown data.

[0078] Once the model performs well in the validation phase, it can be deployed to an actual tachometer calibration device for real-time identification of tachometer display values.

[0079] In some embodiments, the sample images of the displayed values also include tachometer images under different lighting environments and tachometer images affected by stains.

[0080] This can make the sample images diverse. During the training process of the tachometer display value recognition model, in order to ensure that the model has high adaptability and accuracy in actual applications, the sample images need to be diverse. This includes collecting tachometer images under different lighting environments and tachometer images affected by stains. For the lighting environment, the sample images should cover a variety of lighting conditions from strong light to dim light, including direct sunlight, indoor lighting, and cloudy days, etc. The purpose of doing this is to enable the model to learn to accurately identify the displayed values of the tachometer under various lighting effects and improve its robustness at different times and locations.

[0081] At the same time, considering that the tachometer may accumulate dust, oil stains, or other stains during use, resulting in difficult image recognition, it is also very crucial to collect and include these affected sample images in the training process. These images contain tachometer readings with stain occlusion, blurring, or partial display incompleteness, enabling the model to learn how to accurately identify the rotational speed values in the case of common stains or damages in the real environment.

[0082] By training with these diverse sample images, the tachometer display value recognition model can better generalize to various actual scenarios and improve its recognition accuracy and reliability in complex environments.

[0083] In some embodiments, when the imaging unit 1 acquires the tachometer image, it may be affected by the vibration of the motor, resulting in a blurred image and affecting the accurate recognition of the tachometer display value. To solve this problem, the imaging unit 1 usually integrates image stabilization technology, which reduces the impact of vibration on image clarity through software algorithms or hardware devices. Software algorithms may include techniques such as multi-frame fusion and motion compensation. They synthesize a stable image by comparing the differences between consecutive frames, predicting the vibration trend, and adjusting the image data accordingly. In terms of hardware, an optical stabilization system or a mechanical anti-shake device may be adopted. For example, a gyroscope is used to detect the vibration of the camera and drive the compensation mechanism to move in the opposite direction to offset the vibration. Through these image stabilization measures, the imaging unit 1 can provide a clear and stable tachometer image, providing high-quality visual input for the tachometer display value recognition model, thereby improving the recognition accuracy of the tachometer and the reliability of the entire calibration system.

[0084] In some embodiments, such as Figure 2 shown, the tachometer calibration device further includes one or more of a reminder unit 5, a signal processing unit 6, and a wireless communication unit 7.

[0085] The reminder unit 5 is connected to the control and processing unit 3. The control and processing unit 3 is configured to determine that the stain occlusion range on the surface of the tachometer exceeds a set standard range based on the image of the displayed value, and generate a cleaning prompt instruction. The reminder unit 5 is configured to issue a physical reminder signal that the tachometer needs to be cleaned according to the cleaning prompt instruction.

[0086] Specifically, when the control and processing unit 3 analyzes the image of the displayed value captured by the imaging unit 1, it evaluates whether there are stains or other visual obstacles in the display area of the tachometer in the image, and determines whether these stains have reached a preset standard range that affects the recognition accuracy. If the stain occlusion range exceeds this range, the control and processing unit 3 will generate a cleaning prompt instruction that clearly indicates that the tachometer needs to be cleaned. Subsequently, the control and processing unit 3 transmits this instruction to the reminder unit 5, and the reminder unit 5 immediately sends a reminder signal to the operator visually or audibly, such as a flashing warning light or a beeping sound, to prompt the operator that there are obvious stain occlusions on the surface of the tachometer and that cleaning is required to ensure the accuracy of image recognition and calibration. This process ensures that the surface of the tachometer is clean before calibration, thus avoiding misreading or calibration failure caused by stains.

[0087] The signal processing unit 6 is connected between the speed detection unit 2 and the control and processing unit 3. The signal processing unit 6 is configured to perform enhancement processing on the speed detection signal.

[0088] The signal processing unit 6 is mainly responsible for processing and optimizing the original rotational speed detection signal output by the rotational speed detection unit 2. The signal processing unit 6 uses a series of signal processing techniques, such as filtering, amplification, and digital processing, to improve the quality of the signal. Specifically, it may include a band-pass filter to remove high-frequency noise or low-frequency drift generated during motor operation, thereby only retaining the useful signal part containing rotational speed information. In addition, the signal processing unit 6 may also include an amplifier to enhance the signal strength, ensuring that the control processing unit 3 can accurately receive and analyze these signals even when the signal is weak. Finally, through an analog-to-digital converter (ADC), the enhanced analog signal is converted into a digital signal for further data analysis and processing by the control processing unit 3. Through these enhancement processes, the accuracy and reliability of the rotational speed detection signal are significantly improved, providing a solid foundation for the precise calibration of the tachometer.

[0089] The calibration unit 4 is also used to return a calibration completion signal to the control processing unit 3 after calibration is completed, and the control processing unit 3 is also used to generate a calibration record report of the tachometer according to the calibration completion signal.

[0090] Specifically, after completing the calibration process of the tachometer, the calibration unit 4 will send a calibration completion signal to the control processing unit 3, which is a key feedback mechanism to inform the control processing unit 3 that the calibration process has ended. After receiving this signal, the control processing unit 3 will perform the final processing steps, including verifying whether the calibration result meets the preset accuracy standard and generating a detailed calibration record report of the tachometer.

[0091] The calibration record report usually includes the calibration date, time, motor information, initial error value, calibration parameters, calibration result, and any other diagnostic information. The calibration record report not only provides the operator with the detailed results of the calibration but also facilitates future maintenance and auditing work.

[0092] In addition, the control processing unit 3 may also store this report in a database or send it to a host computer or other management systems through an interface for remote monitoring and long-term data tracking. This process ensures the transparency and traceability of the calibration activities, enhancing the quality and efficiency of the entire calibration process.

[0093] The tachometer calibration device also includes a wireless communication unit 7, which is connected to the control processing unit 3 and is used to send the calibration record report to the user terminal of the staff.

[0094] In this embodiment, the tachometer calibration device enhances its functionality and flexibility by integrating a wireless communication unit 7, which is connected to the control processing unit 3 and is mainly responsible for wirelessly transmitting the calibration record report generated during the calibration process to the user-end device of the staff. The wireless communication unit 7 may adopt common wireless communication protocols and technologies such as Wi-Fi, Bluetooth, cellular network (4G / 5G), etc. to achieve real-time remote data transmission. In this way, the staff can remotely monitor the calibration status of the tachometer and receive the calibration results in a timely manner without having to go to the site in person, greatly improving work efficiency.

[0095] Moreover, the wireless communication unit 7 can also support cloud storage and remote access of data, enabling the calibration record report to be shared and analyzed by multiple authorized users, which is convenient for centralized management and maintenance. This wireless communication function is particularly suitable for large factories or distributed facilities, where tachometers may be installed in different locations and the staff needs to flexibly monitor and manage the work from the central control room or mobile devices.

[0096] In some embodiments, the control processing unit 3 is connected to the motor control unit of the target motor and is used to send a speed control instruction to the motor control unit so that the motor control unit controls the speed of the target motor according to the speed control instruction.

[0097] By connecting with the motor control unit of the target motor, the control processing unit 3 realizes the direct control of the motor speed. During the tachometer calibration process, the control processing unit 3 generates accurate speed control instructions according to the preset calibration program or the operator's input. These instructions are sent to the motor control unit through the communication interface, and the motor control unit then analyzes these instructions and adjusts the operating state of the motor accordingly, such as adjusting the power supply, changing the drive current or modifying the drive frequency, etc., to achieve precise control of the speed of the target motor.

[0098] In this way, the control processing unit 3 can ensure that the motor operates at a specific speed point according to the requirements of the calibration program, thus providing a stable and known speed reference for the tachometer. This not only improves the automation level of the calibration process but also ensures the accuracy and reliability of the calibration results. In addition, this connection also allows the tachometer calibration device to perform real-time control of the motor when needed to adapt to different calibration requirements and scenarios, enhancing the flexibility and practicality of the entire system.

[0099] In some embodiments, the tachometer calibration device further includes a metal shell, and the control processing unit 3 is arranged in the metal shell.

[0100] The metal housing of the tachometer calibration device is designed to protect the internal control processing unit 3 and possibly other sensitive electronic components. This robust metal housing not only provides physical protection against impacts, drops, and other forms of mechanical damage to the device but also helps shield external electromagnetic interference, ensuring the accuracy of signal processing and data calculation of the control processing unit 3.

[0101] The metal housing is typically made of corrosion-resistant materials and can withstand harsh environments such as humidity, dust, oil, and chemicals, thereby enhancing the durability and reliability of the device. In addition, the design of the metal housing also takes into account the heat dissipation performance to ensure that the control processing unit 3 can maintain an appropriate temperature even during long-term operation, avoiding performance degradation or damage caused by overheating. By integrating key components such as the control processing unit 3 into the metal housing, the tachometer calibration device can operate stably in various industrial environments and meet the needs of long-term and frequent use.

[0102] The tachometer calibration device of this embodiment adopts precise and automated processes to ensure the accuracy and reliability of the motor tachometer. The following is the detailed workflow:

[0103] 1. Start the device: Connect the power supply and start the tachometer calibration device, including the control processing unit 3, the imaging unit 1, the speed detection unit 2, and the wireless communication unit 7.

[0104] 2. Image capture: The imaging unit 1 aims at the tachometer of the target motor and captures images of the tachometer. These images include the indicated values of pointer-type or digital-type displays and may be obtained under different lighting conditions and environmental situations.

[0105] 3. Image stabilization: The imaging unit 1 adopts image stabilization technology to cope with the image blurring caused by motor vibration and ensure image clarity.

[0106] 4. Speed detection: The speed detection unit 2 uses corresponding sensors to detect the actual speed of the target motor and generates a speed detection signal.

[0107] 5. Signal processing: The signal processing unit 6 enhances the speed detection signal to ensure the quality and accuracy of the signal.

[0108] 6. Image recognition: The control processing unit 3 calls the tachometer display value recognition model to perform recognition processing on the image of the indicated value captured by the imaging unit 1 to obtain the indicated speed value.

[0109] 7. Comparison and analysis: The control processing unit 3 compares the indicated speed value and the speed detection value to determine whether there is a difference and judge whether calibration is required.

[0110] 8. Calibration process: If calibration is required, the control processing unit 3 calculates calibration parameters, generates a calibration processing signal, and sends it to the calibration unit 4 for actual calibration operations.

[0111] 9. Feedback signal: After the calibration unit 4 completes calibration, it returns a calibration completion signal to the control processing unit 3.

[0112] 10. Record report: The control processing unit 3 generates a calibration record report for the tachometer and can send it to the staff's user terminal through the wireless communication unit 7.

[0113] 11. Control motor speed: If necessary, the control processing unit 3 sends a speed control instruction to the motor control unit of the target motor to adjust the motor speed to a specific value required for calibration.

[0114] 12. Remind to clean: If during the image recognition process, it is found that the stain coverage on the surface of the tachometer exceeds the set standard, the control processing unit 3 will generate a cleaning prompt instruction, and the reminder unit 5 will send a cleaning reminder signal.

[0115] 13. End calibration: After completing the calibration process, the tachometer calibration device can continue to monitor the motor speed or wait for the next calibration instruction.

[0116] The entire workflow is automated, reducing human intervention and improving the efficiency and accuracy of calibration. At the same time, through the wireless communication unit 7, the staff can remotely monitor the calibration process and results, improving the convenience of work.

[0117] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principles of the present invention, several improvements and deformations can be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A tachometer calibration device, characterized in that, Comprising: A camera unit for photographing the tachometer of a target motor to obtain an image of the indicated value of the tachometer; the camera unit integrates image stabilization technology to reduce the impact of motor vibration on image clarity. The image stabilization technology includes multi-frame fusion and motion compensation, and synthesizes a stable image by comparing the differences between consecutive frames, predicting the vibration trend, and adjusting the image data accordingly. A rotational speed detection unit for detecting the rotational speed of the target motor and generating a rotational speed detection signal. A control and processing unit, connected to the camera unit and the rotational speed detection unit respectively, for determining the indicated rotational speed value displayed by the tachometer according to the image of the indicated value, determining the detected rotational speed value of the target motor according to the rotational speed detection signal, determining that the tachometer needs calibration processing according to the detected rotational speed value and the indicated rotational speed value, and generating a calibration processing signal. Specifically, calculate the error value between the indicated rotational speed value and the detected rotational speed value, and combine the performance parameters of the tachometer and historical calibration data to calculate the calibration parameters that need to be adjusted using a mathematical model and a calibration strategy. The calibration strategy includes: selecting key calibration points representing the performance of the entire range of the tachometer; determining the calibration order, calibrating the high or low end of the range first, or using a step-by-step calibration method to gradually approach the ideal value; and calculating the calibration step value. The calibration parameters include: the magnitude of adjustment, the step size of adjustment, the rate of adjustment, and compensation for environmental factors. A calibration unit, connected to the tachometer and the control and processing unit respectively, for calibrating the tachometer according to the calibration processing signal. The control and processing unit is specifically used to call a preset tachometer display value recognition model to perform recognition processing on the image of the indicated value to obtain the indicated rotational speed value. The training process of the tachometer display value recognition model includes: obtaining a plurality of indicated value sample images, which include pointer-type indicated value sample images and digital-type indicated value sample images, as well as tachometer images under different lighting environments and tachometer images affected by stains; marking the true values of the pointer-type indicated value sample images and the digital-type indicated value sample images in the indicated value sample images to obtain a training data set; and training the tachometer display value recognition model through the training data.

2. The tachometer calibration device according to claim 1, characterized in that, It further includes a reminder unit, the reminder unit is connected to the control and processing unit, the control and processing unit is used to determine that the surface stain occlusion range of the tachometer exceeds the set standard range according to the image of the indicated value and generate a cleaning prompt instruction, and the reminder unit is used to send a reminder signal that the tachometer needs to be cleaned according to the cleaning prompt instruction.

3. The tachometer calibration device according to claim 1, characterized in that, It further includes a signal processing unit, the signal processing unit is connected between the rotational speed detection unit and the control and processing unit, and the signal processing unit is used to enhance the rotational speed detection signal.

4. The tachometer calibration device according to claim 1, characterized in that, The calibration unit is further used to return a calibration completion signal to the control and processing unit after calibration is completed, and the control and processing unit is further used to generate a calibration record report of the tachometer according to the calibration completion signal.

5. The tachometer calibration device according to claim 4, characterized in that, It further includes a wireless communication unit, which is connected to the control processing unit and is used to send the calibration record report to the client of the staff member.

6. The tachometer calibration device according to claim 1, characterized in that, The control processing unit is connected to the motor control unit of the target motor and is used to send a speed control instruction to the motor control unit so that the motor control unit controls the speed of the target motor according to the speed control instruction.

7. The tachometer calibration device according to claim 1, wherein It further includes a metal shell, and the control processing unit is arranged in the metal shell.

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