Portable straightness measuring device and its measuring method and application

Abstract

The application relates to the technical field of precision measurement, and discloses a portable straightness measurement device, a measurement method thereof and application, which solves the problems of low precision, complicated operation process and low measurement efficiency in the traditional straightness measurement process. The device comprises a transmitting device and a receiving device which cooperate with each other. The transmitting device is internally provided with a laser driving module, a laser emitting module and a first power supply module. The receiving device is internally provided with a PSD receiving and detecting module, a laser ranging module, an integrated signal processing unit, a PCB control board of a main control computing unit and a communication unit and a second power supply module. The laser ranging module is coaxially arranged with a reference laser beam, and the straightness error of a measured workpiece is solved. The detection is completed through device installation calibration, multi-point sampling, signal conversion, error elimination and data redundancy output. The application is small and portable, has high measurement precision and detection efficiency, and is stable and reliable in communication, and is widely applied to straightness detection in multiple scenes such as automobile wheel positioning, machine tool guide rails, large castings and industrial pipelines.

Description

Technical Field

[0001] This invention relates to the field of precision measurement technology, specifically to a portable straightness measuring device, its measurement method, and its application. Background Technology

[0002] Straightness is a core indicator for evaluating the geometric accuracy of long and narrow workpieces. It directly affects the machining accuracy of machine tools, the stability of vehicle operation, the sealing of pipeline transportation, and the assembly quality of heavy equipment. It is an indispensable testing parameter in industrial production, equipment operation and maintenance, and quality inspection.

[0003] Currently, mainstream straightness measurement technologies are mainly divided into two categories: traditional manual measurement and optical precision measurement. Traditional manual measurement methods include the ruler method, the level method, and the autocollimator method. Among them, the ruler method uses a high-precision ruler combined with visual observation or a dial indicator for detection. It is relatively simple to operate, but the measurement accuracy is limited, and the results are highly dependent on the operator's experience, making it difficult to obtain stable and high-precision quantitative data. The level method obtains tilt angle information by moving the bridge plate segment by segment, and then converts it into straightness error through manual calculation. Although the cost is moderate, the process is complex, data processing is time-consuming, detection efficiency is low, and it is prone to human calculation deviations. The autocollimator method achieves small angle measurement based on the principle of optical autocollimation and has high accuracy. However, the optical path adjustment is difficult, the professional skills of the operator are required, and the subsequent data processing steps are cumbersome, making it difficult to meet the actual needs of rapid batch testing on site.

[0004] Optical precision measurement is represented by laser collimation and laser interferometry. Laser interferometry, based on the principle of interference, can achieve extremely high measurement accuracy, but the equipment is expensive and extremely sensitive to factors such as ambient temperature, airflow disturbance, and vibration. It is usually only suitable for laboratory conditions with constant temperature and humidity, and its application is limited in complex working conditions such as workshops or outdoors. Conventional laser collimation devices use a laser beam as a reference and use a photodetector to collect the offset to complete the straightness detection. Although it can achieve non-contact measurement, existing solutions generally lack a real-time optical path distance compensation mechanism. When the measurement distance changes, it is easy to introduce significant calculation errors. Moreover, most devices use a single communication mode, which is prone to communication interruption or data loss in the complex electromagnetic environment of industrial sites. At the same time, the overall integration is not high, and the portability and adaptability to multiple scenarios are weak. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a portable straightness measuring device with high precision, high efficiency and high adaptability.

[0006] Another object of the present invention is to provide a specific method for performing measurements using the aforementioned portable straightness measuring device.

[0007] Another object of the present invention is to provide a specific application of the above-described portable straightness measuring device.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution: a portable straightness measuring device, comprising a transmitting device and a receiving device that work together.

[0009] The transmitting device is provided with a first housing, which integrates a laser driving module, a laser emitting module and a first power supply module; the laser driving module is electrically connected to the laser emitting module and is used to drive the latter to emit a line reference laser beam; the first power supply module is connected to both the laser driving module and the laser emitting module to provide them with working power. The receiving device includes a second housing, which internally houses a PSD receiving and detection module, a laser ranging module, a PCB control board, and a second power supply module. The PSD receiving and detection module contains a one-dimensional PSD sensor for receiving a line-shaped reference laser beam spot from the laser emitting module and outputting an analog electrical signal corresponding to the spot's position. The laser ranging module is a self-emitting and self-receiving ranging unit, whose ranging optical path is coaxially arranged with the line-shaped reference laser beam in space, enabling real-time acquisition of the optical path distance between the emitting and receiving devices. The PCB control board integrates a signal processing module and a main control unit. The system comprises a calculation module and a communication module. The main control calculation module is connected to both the laser ranging module and the signal processing module. The signal processing module converts the analog electrical signal output by the PSD receiving and detection module into a digital signal and transmits it to the main control calculation module. Based on this digital signal, the optical path distance measured by the laser ranging module, and the spot position information, the main control calculation module calculates the straightness error of the workpiece being measured. The communication module is connected to the main control calculation module and is used to transmit measurement data externally. The second power supply module is electrically connected to the PSD receiving and detection module, the laser ranging module, and the PCB control board to provide them with power.

[0010] This technical solution utilizes a non-contact optical measurement method to achieve real-time, high-precision, and automated detection of straightness values. A linear laser beam emitted from the transmitting device serves as a spatial straightness reference. When the workpiece under test exhibits bending deformation, the receiving device, moving along the workpiece, undergoes relative deflection with the transmitting end, causing a lateral shift in the laser spot's position on the photosensitive surface of the receiving end. The laser ranging module within the receiving device is a self-emitting and self-receiving unit, spatially coaxial with the reference optical path, and can synchronously acquire the optical path distance at the current measurement point. The main control calculation module combines the spot offset and the real-time optical path distance to calculate the deflection angle through geometric relationships, ultimately obtaining the straightness error along the entire length of the workpiece. The split structure, coupled with built-in power supply, enables cordless and portable testing.

[0011] Laser drive module: As the control core of laser emission, it adopts a constant current drive circuit design, including a current regulation unit and a drive control circuit, to ensure the stability of the laser source.

[0012] Laser emitting module: includes a line laser emitter and a fixing bracket; the line laser emitter is used to emit a line laser beam, and the fixing bracket is used to securely install the laser emitting module at a preset detection position to ensure the stability and repeatability of the laser emission angle.

[0013] Laser ranging module: Integrating a high-precision infrared laser ranging sensor and a digital signal output unit, it is coaxially integrated with the line laser transmitter. It can acquire the vertical optical path distance from the transmitter to the PSD photosensitive surface in real time and transmit it to the main control computing module. The ranging module has a built-in light-shielding and filtering structure to suppress ranging drift caused by environmental noise, outputting stable distance values ​​and supporting accurate calculation of straightness and deflection angle.

[0014] The PSD receiving and detection module includes a PSD position-sensitive detector, a signal preprocessing unit, and a mounting and calibration bracket. The PSD position-sensitive detector uses a one-dimensional PSD sensor to receive the laser mark spot signal and convert the spot position information into an analog electrical signal output. The signal preprocessing unit filters, reduces noise, and amplifies the analog electrical signal output by the PSD to eliminate ambient light interference and signal noise. The mounting and calibration bracket is used to fix the PSD receiving and detection module on the other side of the vehicle at a preset position corresponding to the transmitting module, ensuring that the relative position between the PSD and the laser transmitter is fixed and calibrable.

[0015] Signal processing module: The AD conversion unit converts the pre-processed analog electrical signal into a digital signal, realizing the digital conversion from optical signal to electrical signal; it awaits reading and processing by the main control computing module to ensure the continuity and stability of data transmission.

[0016] Main control computing module: Utilizing the GD32F103VE as the core computing unit, it reads the buffered digital signal, extracts the offset of the light spot center position, and, combined with a mathematical model, calculates parameters such as the straightness and deflection angle of the measured object in real time, and performs data processing and storage. Integrated communication control logic monitors the signal reception status of the communication module in real time and controls the switching of communication modes.

[0017] Communication module: Composed of a wireless transmission module and a CAN communication module, it realizes bidirectional transmission of measurement data and adopts a redundant design to ensure communication stability.

[0018] Power supply module: It adopts a rechargeable lithium battery pack + voltage regulator circuit design to provide a stable operating voltage for the laser emission module, PSD receiving and detection module, signal processing module, main control computing module and human-machine interaction module. It is suitable for power supply needs in various scenarios such as outdoor and workshop, and has overcharge and over-discharge protection functions as well as low battery and full battery indication functions.

[0019] To further optimize the present invention, the laser driving module adopts a constant current driving circuit to output a stable current and ensure constant laser power; the laser emitting module emits a red line laser with a wavelength of 650±10nm, and the effective working distance range is 3000mm to 10000mm.

[0020] To further optimize the present invention, the PSD receiving and detection module is also equipped with a signal pre-processing unit, which is electrically connected to the one-dimensional PSD sensor and performs filtering, amplification and noise reduction processing on the analog electrical signal output by the sensor; the signal processing module on the PCB control board has a built-in AD conversion unit, which is used to convert the pre-processed analog signal into a digital signal and send it to the main control computing module.

[0021] To further optimize the present invention, the main control calculation module embeds a least squares fitting algorithm, which eliminates two types of systematic errors—hardware installation zero bias and overall workpiece tilt—by fitting a reference straight line in layers, thereby accurately calculating the true straightness error of the workpiece.

[0022] To further optimize the present invention, the communication module on the PCB control board includes a wireless transmission unit and a CAN bus transmission unit, forming a redundant communication link; the main control computing module monitors the response status of the wireless link in real time, and automatically switches to the CAN bus transmission unit to upload data when the wireless link times out without response.

[0023] To further optimize the present invention, the first housing is provided with a battery compartment, and the outer side is provided with a first mounting and fixing shaft and a protective lens; the battery compartment is equipped with an energy storage unit of the first power supply module; the first mounting and fixing shaft is used to connect an external clamp to fix the emitting device; the protective lens covers the light outlet of the laser emitting module.

[0024] To further optimize the present invention, the outer side of the second housing is provided with a charging interface, a communication interface, a PSD window, a ranging window and a second antenna interface; the PSD window faces the one-dimensional PSD sensor and the ranging window corresponds to the laser ranging module; both windows are equipped with filters on their inner sides to shield the interference of ambient stray light on the detection optical path.

[0025] To further optimize the present invention, both the first power supply module and the second power supply module adopt a structure of rechargeable lithium battery pack with voltage regulator circuit, which has overcharge and over-discharge protection functions, and the device can work continuously for no less than 8 hours after a single full charge.

[0026] To further optimize the present invention, it also includes a mounting and calibration frame used in conjunction with the transmitting and receiving devices; after the mounting and calibration frame completes the factory zero-position calibration with the standard calibration equipment, the main control calculation module will store the corresponding zero-bias compensation parameters.

[0027] The method for measuring straightness using the aforementioned portable straightness measuring device includes the following steps: Step S1: Install the transmitting device and the receiving device at both ends of the workpiece to be measured, and adjust their relative positions so that the line reference laser beam output by the laser transmitting module is parallel to the axis to be measured of the workpiece. Step S2: Turn on the transmitting and receiving devices. The laser driving module controls the laser transmitting module to emit a line reference laser beam. At the same time, the laser ranging module and PSD receiving and detection module in the receiving device start working. Step S3: Move the receiving device along the axis of the workpiece being measured to simultaneously acquire the analog signal of the light spot position and the optical path distance data at multiple measuring points; Step S4: The signal processing module on the PCB control board converts the analog electrical signal of the light spot position output by the PSD receiving and detection module into a digital signal and transmits it to the main control computing module; Step S5: The main control calculation module combines the optical path distance data and the digital signal of the light spot position of each measuring point to calculate the straightness error of the workpiece being measured; Step S6: Send the straightness error data to the outside via the communication module on the PCB control board.

[0028] To further optimize the above straightness measurement method, the specific calculation process for the straightness error of the workpiece in step S5 is as follows: The main control calculation module calculates the original deflection angle of each measuring point based on the optical path distance and spot offset of each measuring point; it uses the least squares method to fit the reference straight line of the whole field, and eliminates the systematic errors caused by the zero bias of hardware installation and the overall tilt of the workpiece layer by layer, thereby obtaining the true deflection angle of each measuring point; the difference between the maximum and minimum values ​​of the true deflection angles of all measuring points is used as the straightness error of the entire length of the measured workpiece.

[0029] To further improve the reliability of the above straightness measurement method, step S6 adopts a dual redundancy method of wireless transmission and CAN bus transmission to output data; the main control computing module prioritizes the wireless transmission unit to upload measurement results and monitors the response status of the wireless link in real time. Once the wireless link times out without receiving a response, it automatically switches to the CAN bus transmission unit to complete the data upload.

[0030] To further improve the above straightness measurement method, a factory pre-calibration step is included before step S1: The device is calibrated to zero using a calibration rack and standard calibration equipment. The emission angle of the laser emission module is adjusted to the reference zero position, and the zero offset compensation parameters obtained from the calibration are stored in the main control calculation module for system error compensation in subsequent measurement processes.

[0031] The entire process of a single measurement, from sampling, signal processing, error calculation to data output, takes no more than 30 seconds.

[0032] The specific application scenarios of the aforementioned portable straightness measuring device or its measurement method include at least one of the following: Application 1: By using a special wheel clamp to fix the transmitter and receiver to the wheels on both sides of a vehicle, the straightness parameters of the wheel toe-in can be measured, realizing the automated detection and data upload of wheel alignment for passenger cars and commercial vehicles. It is suitable for four-wheel alignment detection in automotive repair. Application 2: Fix the device with a general-purpose fixture, perform multi-point sampling along the gantry guide rail, detect the straightness error of the entire guide rail, ensure the geometric accuracy of machine tool processing, and is suitable for the inspection of machine tool gantry guide rails; Application 3: Replace with an extended fixture adapted to large workpieces to measure the straightness of the outer datum of long castings. This method is suitable for straightness inspection of large castings. Application 4: When used with a pipe ring clamp, the receiving device moves along the pipe axis to detect the straightness of bending deformation in long-distance pipelines or equipment pipelines. It is suitable for industrial pipeline straightness detection.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The present invention adopts a coaxial integrated laser emission module and laser ranging module, and collects the spot offset with a PSD position sensitive detector. It can combine real-time optical path distance data to compensate for the deflection angle and straightness, eliminating the system error introduced by the measurement distance fluctuation. At the same time, the benchmark fitting algorithm is used to eliminate the hardware installation zero bias and the overall tilt error of the workpiece in layers, retaining only the workpiece's own deformation. It can maintain stable detection accuracy in the entire range and adapt to the detection needs of workpieces of different lengths. (2) The present invention adopts a split modular design with a built-in rechargeable power supply module, which does not require an external power supply and complex supporting equipment. It is small in size and easy to carry, and can be flexibly deployed in various industrial sites. By matching different specifications of installation fixtures, it can be adapted to various inspection objects such as machine tool guide rails, automobile wheel toe-in, industrial pipelines, and large castings, and has a wide range of application scenarios. (3) The present invention adopts a redundant communication architecture that combines wireless transmission and bus transmission. It can automatically switch the communication mode according to the link status, avoid data loss caused by the failure of a single communication link, adapt to the complex electromagnetic environment in the workshop, and ensure the stable transmission and traceability of measurement data. (4) This invention realizes full automation of data acquisition, signal processing and error calculation. There is no need for manual recording of data segment by segment and manual calculation. A single test can be completed in a short time, which greatly improves the testing efficiency and is suitable for batch testing and on-site rapid troubleshooting scenarios. At the same time, the device has built-in factory calibration parameters, the operation process is simple, the requirements for the professional skills of operators are reduced, and it is easy to promote and use in production workshops, repair shops and other scenarios. Attached Figure Description

[0034] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a three-dimensional structural diagram of the launching device in this invention; Figure 2 This is a three-dimensional structural diagram of the receiving device in this invention from one perspective; Figure 3 This is a three-dimensional structural schematic diagram of the receiving device in this invention from another perspective; Figure 4 This is a flowchart of the straightness measurement method in this invention; Figure 5 This is a schematic diagram of the calibration process of the launching device in this invention. Figure 1 ; Figure 6 This is a schematic diagram of the calibration process of the launching device in this invention. Figure 2 ; Figure 7 This is a schematic diagram of the installation of the transmitting device and the receiving device in this invention; Figure 8 This is the coordinate diagram for calculating the straightness of the guide rail in this invention; Figure 9 This is a flowchart of the operation process of the present invention.

[0035] Wherein: 1—Transmitting device, 11—Laser driving module, 12—Laser emitting module, 13—First housing, 14—First power supply module, 15—Battery compartment, 16—First mounting and fixing axis, 17—Protective lens, 2—Receiver, 21—PSD receiving and detection module, 22—Laser ranging module, 23—PCB control board, 24—Second power supply module, 25—Charging interface, 26—Communication interface, 27—PSD window, 28—Range measuring window, 29—Second antenna interface, 210—Second housing. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, the terms "first" and "second" are limited to descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly including one or more of the feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] Example 1: The main structure of this embodiment is as follows: Figures 1-3 As shown, it includes a transmitting device 1 and a receiving device 2 that cooperate with each other; The transmitting device 1 includes a first housing 13, which is provided with a laser driving module 11, a laser emitting module 12, and a first power supply module 14. The laser driving module 11 is electrically connected to the laser emitting module 12, and the laser driving module 11 drives the laser emitting module 12 to emit a line-shaped reference laser beam. The first power supply module 14 is electrically connected to both the laser driving module 11 and the laser emitting module 12, providing power to both modules. The receiving device 2 includes a second housing 210, within which are disposed a PSD receiving and detection module 21, a laser ranging module 22, a PCB control board 23, and a second power supply module 24. The PSD receiving and detection module 21 includes a one-dimensional PSD sensor, which receives the spot of the line-shaped reference laser beam emitted by the laser emitting module 12 and outputs an analog electrical signal corresponding to the spot's position. The laser ranging module 22 includes a transceiver ranging unit, whose ranging optical path is spatially coaxial with the line-shaped reference laser beam, and it acquires the optical path distance between the emitting device 1 and the receiving device 2 in real time. The PCB control board 23 integrates a signal processing module, a main control computing module, and a communication module. The module is connected to the laser ranging module 22 and the signal processing module respectively. The signal processing module converts the analog electrical signal corresponding to the spot position output by the PSD receiving and detection module 21 into a digital signal and transmits it to the main control and calculation module. The main control and calculation module calculates the straightness error of the workpiece under test based on the digital signal converted by the signal processing module and the optical path distance and spot position signal collected by the laser ranging module 22. The communication module is connected to the main control and calculation module and transmits measurement data to the outside. The second power supply module 24 is electrically connected to the PSD receiving and detection module 21, the laser ranging module 22 and the PCB control board 23 respectively, and provides power to the PSD receiving and detection module 21, the laser ranging module 22 and the PCB control board 23.

[0040] The transmitter's technical requirements are as follows: (1) Red light, wavelength 650±10 nm, monochromatic continuous laser (2) Working distance: 3000 mm~10000 mm.

[0041] (3) At both working distances, the width of the line is ≤2 mm.

[0042] (4) Depth of field: Within a working distance of ±5 mm, the width of the line is ≤2 mm.

[0043] (5) Transmission power: ≤1 mW / mm at the center of the line 2 .

[0044] (6) Battery-powered operation time is not less than 8 hours.

[0045] The receiver's technical requirements are as follows: (1) Receiving surface ≥ 30 mm.

[0046] (2) Battery-powered operation time is not less than 8 hours.

[0047] The method for measuring straightness using this portable straightness measuring device is as follows: Figure 4As shown, it includes the following steps: Step S1: Factory calibration of the device Step S11: Calibrate the environment Under suitable temperature, all calibration operations are performed on a standard optical platform, and the receiving and transmitting devices are fixed in the corresponding holes on the platform using the matching fixtures; Step S12: Calibrate the instrument Autocollimator: A high-precision metrological instrument that uses the principle of light selfcollimation to convert angle measurement into linear measurement. It is used for small angle measurement and flatness, straightness and parallelism detection. The emitted light is surface light. Step S13: Calibration Process Step S131: Install a plane mirror next to the emission port of the transmitting device. Use an autocollimator to illuminate the mirror and adjust the position of the transmitting end so that the reflected light is parallel to the incident light, that is, the crosshairs of the autocollimator coincide with the zero point. At this time, it can be determined that the emission surface of the transmitting device is perpendicular to the light emitted from the autocollimator. Figure 4 As shown; Step S132: Turn on the transmitting device to illuminate the autocollimator with laser light. To prevent direct laser light from damaging the autocollimator's sensor, install a high-attenuation filter in front of the autocollimator. Adjust the laser emission angle so that the emitted laser spot formed on the autocollimator's receiving device coincides with the zero point. At this point, it can be determined that the emitted laser light is parallel to the emitted light from the autocollimator. Because the emission surface of the transmitting device is perpendicular to the emitted light from the autocollimator, it can be determined that the emitted laser light is perpendicular to the emission surface of the transmitting device. Figure 5 As shown; Step S14: Initial zero-point calibration Check the deviation of the crosshairs relative to the zero point in the autocollimator software, reduce the deviation to the minimum acceptable range (within ±5 arcseconds), record the precise readings of the autocollimator at this point, denoted as ΔX and ΔY, and set the readings to zero using the autocollimator software. Simultaneously, record the calibration time, ambient temperature, and the autocollimator readings at the time of calibration in the experimental log as data backup; Step S15: Ensure the laser is perpendicular to the workpiece being measured. This device emits a vertical laser stripe. To ensure the entire stripe is vertical, the transmitter is rotated on the mounting plane at the factory so that the readings at the top and bottom of the stripe are consistent during reception, meaning the entire stripe is vertical. Before use, the device's built-in tilt sensor will provide the tilt angle values ​​for both transmission and reception. We need to adjust the tilt angle to 0 to ensure the transmitter and receiver are aligned and parallel.

[0048] Step S16: Calibration reference: Initial zero point of the autocollimator Methods for storing and retrieving calibration parameters: The autocollimator software and calibration operation interface usually have functions such as "save", "import data" or "report output". The data will be saved on the computer for easy retrieval and processing later. Calibration error compensation mechanism: Instrument calibration compensation: The periodic verification of the autocollimator is strictly in accordance with the national metrological regulations. The standard angle generating device is used to perform the verification within the full range, and the indication error at each point is given. Software and algorithm correction: The instrument's measurement principle itself has nonlinear errors, and modern autocollimators often use algorithms such as polynomial fitting and two-dimensional interpolation for high-precision compensation; Environmental and operational compensation: Preheat the instrument for at least 30 minutes before measurement to reduce temperature drift, and use it in a stable environment. Operationally, take the average of measurements in both the forward and reverse directions to eliminate hysteresis error. The parameter requirements for standard calibration parts are shown in Table 1: Table 1 Parameter Requirements for Standard Calibration Parts

[0049] Step S2: Device Installation: Fix the transmitter with the integrated laser ranging module and the receiver with the one-dimensional PSD to both ends of the guide rail. Adjust the transmitter bracket and the PSD mounting and calibration bracket so that the linear laser beam is parallel to the axis of the guide rail being measured. Figure 7 As shown; Step S3: Equipment Power-On Initialization: Power is turned on to the transmitting and receiving devices. The receiving end reads the setting information in the non-volatile memory. The laser drive module stably drives the linear laser emitter to emit light. The laser ranging module simultaneously begins to collect the real-time optical path distance from the transmitting end to the PSD photosensitive surface. Signal Preprocessing and Digitization: The signal preprocessing unit filters and amplifies the analog electrical signal output from the PSD, and the AD conversion unit converts it into a digital signal. Step S4: Multi-point sampling: Move the receiving device at a constant speed along the guide rail under test, and divide the entire guide rail into several measurement points. At each measurement point, the laser ranging output distance value and the PSD spot lateral offset analog signal are collected simultaneously to complete the acquisition of multiple sets of data throughout the entire journey.

[0050] Step S5: Signal preprocessing and digitization: The signal preprocessing unit filters and reduces noise and amplifies the analog electrical signal output by the PSD, and then converts it into a digital signal through the AD conversion unit and buffers it in the main control module.

[0051] Step S6: Data Fitting and Error Removal: The main control calculation module reads all measurement point distance and spot offset data, first calculates the deflection angle of each measurement point, and then uses least squares to fit the reference straight line to remove two types of systematic errors: zero bias in hardware installation and overall tilt of the guide rail, to obtain the true deflection angle that only reflects the deformation of the guide rail itself.

[0052] Step S7: Straightness calculation of the guide rail: Extract the maximum and minimum values ​​of the true deformation deflection angle of all measuring points. The difference between the two values ​​is the straightness error of the entire length of the guide rail. Step S8: Measurement result output: The communication module transmits the straightness error data to the outside world through wireless communication or CAN bus, completing the entire straightness detection process of the guide rail.

[0053] The entire process of a single measurement, from sampling, signal processing, error calculation to data output, takes no more than 30 seconds.

[0054] Example 2: This embodiment, based on the above embodiments, further defines the specific operation process of the portable straightness measuring device during measurement, such as... Figure 9 As shown, it includes the following steps: (1) Power-on initialization of each module: After the device is powered on, the software starts automatically, reads each parameter (device address, device communication rate, sampling step size, total number of samplings, etc.) stored in the power-off memory, and then enters the initialization process to ensure that each module is in a normal working and ready state.

[0055] (2) Synchronous acquisition of multi-source data and digital filtering: After initialization, the data acquisition stage begins. The main control calculation module synchronously reads the optical path distance output by the laser ranging module and the original analog signal of the spot offset output by the PSD sensor; and performs digital filtering on the two sets of acquired data.

[0056] (3) Filtered data anomaly detection and alarm handling: The software verifies the range and signal strength of the filtered distance and spot offset data. If anomalies such as signal over-range or spot loss occur, an alarm is triggered immediately, and the communication module uploads the fault information to the external terminal, and the current measurement process is terminated directly; if there are no data anomalies, the next calculation process is entered.

[0057] (4) Solve the straightness of the guide rail based on the least squares algorithm: The main controller extracts the filtered spot offset and optical path distance, calculates the deflection angle of each measuring point, fits the reference straight line to eliminate the system error of zero installation offset and overall tilt of the guide rail, calculates the true deformation deflection angle of each measuring point, and obtains the straightness error of the entire length of the guide rail through extreme value difference calculation. After the calculation is completed, the measurement results are cached.

[0058] (5) Communication module adaptively switches transmission mode: The communication module detects the wireless link response signal in real time. When the wireless communication is normal, the straightness data is uploaded through the wireless channel. If the wireless signal is lost for 3 seconds, it automatically switches to CAN bus transmission. Dual link redundancy is used to ensure continuous and stable output of measurement data.

[0059] (6) Process End: After the alarm information or data is sent, the software process ends, and the device performs the next measurement or shuts down by power-off. The other parts of this embodiment are the same as those in the above embodiments, and will not be described again.

[0060] Example 3: This embodiment, based on the above embodiment, further specifies that the laser driving module adopts a constant current driving circuit to output a stable current and ensure constant laser power; the laser emitting module emits a red line laser with a wavelength of 650±10nm, with an effective working distance range of 3000mm to 10000mm. The output power stability of the laser source directly affects the position detection accuracy of the PSD. Current fluctuations and temperature drift will cause changes in laser intensity, thereby introducing position measurement errors; the constant current driving circuit can stabilize the driving current through a current negative feedback mechanism to ensure constant laser output power. The selection of the 650±10nm red light band, which is within the visible light range, facilitates intuitive alignment of the optical path by on-site operators; the working distance of 3000mm to 10000mm covers the measurement range requirements of mainstream industrial inspection scenarios such as machine tool guideways, automobile wheels, and industrial pipelines.

[0061] The laser driving module 11 adopts a constant current driving circuit architecture with a built-in current sampling feedback loop. The voltage input from the first power supply module 14 is converted into a stable constant current output to the laser emitting module 12 through the constant current circuit. When the ambient temperature fluctuates or the power supply voltage changes slightly, the driving current always remains at the set value to ensure the output power of the laser emitting module 12 is stable and to avoid PSD detection offset caused by the fluctuation of the spot intensity.

[0062] The laser emitting module 12 employs a line-shaped laser diode, emitting a red line-shaped laser with a wavelength of 650±10nm. After being shaped by an optical cylindrical lens, the effective working distance range is 3000mm to 10000mm, and the line width at both ends of the range is ≤2mm, meeting the spot recognition accuracy requirements of the PSD across the entire range. Other parts of this embodiment are the same as those in the above embodiments and will not be repeated.

[0063] Example 4: This embodiment, based on the above embodiments, further defines the PSD receiving and detection module. The PSD receiving and detection module 21 also includes a signal pre-processing unit, which is electrically connected to the one-dimensional PSD sensor. The signal pre-processing unit filters, amplifies, and reduces noise on the analog electrical signal output by the one-dimensional PSD sensor. The signal processing module on the PCB control board 23 has a built-in AD conversion unit. The AD conversion unit converts the analog electrical signal output by the PSD receiving and detection module 21 into a digital signal and transmits it to the main control computing module. The analog electrical signal output by the one-dimensional PSD sensor based on the transverse photoelectric effect is very weak, and the ambient stray light and electromagnetic interference in the industrial environment will add a lot of noise to the signal. The signal pre-processing unit filters out high-frequency noise through a filtering circuit and amplifies the weak signal through an operational amplifier, which can significantly improve the signal-to-noise ratio and ensure signal quality. The analog signal cannot be directly recognized by the digital main control chip, so it is necessary to convert the continuous analog voltage signal into a discrete digital quantity through an AD conversion unit to realize the complete link conversion from optical signal to digital operation signal.

[0064] The PSD receiving and detection module 21 also includes a signal pre-processing unit, which is electrically connected to the one-dimensional PSD sensor. After being irradiated by a line laser spot, the one-dimensional PSD sensor outputs a weak analog current signal that is linearly related to the center position of the spot. This signal first enters the signal pre-processing unit. It first passes through a second-order low-pass filter circuit to filter out high-frequency noise generated by environmental electromagnetic interference, and then passes through a high-precision operational amplifier for fixed-rate amplification, outputting an analog voltage signal with stable amplitude and controllable noise.

[0065] The signal processing module on the PCB control board 23 has a built-in AD conversion unit. The pre-processed analog voltage signal is input to the AD conversion unit, where it undergoes analog-to-digital conversion at a set sampling frequency to generate a digital code corresponding to the horizontal position of the light spot. The converted digital signal is directly transmitted to the buffer of the main control computing module, awaiting subsequent calculation and use. Other parts of this embodiment are the same as those in the above embodiment and will not be described again.

[0066] Example 5: This embodiment, based on the above embodiments, further defines the main control calculation module. This module embeds a least-squares fitting algorithm, which eliminates two types of systematic errors—hardware installation bias and overall workpiece tilt—by fitting a reference straight line in layers, thereby accurately calculating the true straightness error of the workpiece. The directly acquired raw spot offset is superimposed with two types of systematic errors unrelated to the workpiece's own deformation: one is the fixed bias caused by hardware assembly (installation deviation between the PSD photosensitive center and the ranging optical path, and housing assembly tolerances); the other is the same-direction offset caused by the overall workpiece installation tilt. These two types of errors mask the true deformation of the workpiece. By fitting a reference straight line to all measurement points using the least squares method, the systematic error components and the true deformation can be separated. After layered elimination, only the deflection angle reflecting the workpiece's own bending is obtained. Finally, the straightness error is obtained through the extreme value difference, significantly improving the accuracy of the measurement results.

[0067] The specific calculation process for the straightness error of the workpiece under test is as follows: The specific calculation process is as follows: Step S71: Move the receiver equipped with the one-dimensional PSD and laser rangefinder along the axis of the track being measured / the wheel measurement direction to evenly distribute the measurement points, and collect the perpendicular optical path distance from the laser emitter to the receiver at each point, recording it as the measurement point distance. X i The lateral offset of the light spot relative to the center of the laser reference is simultaneously collected at the same measuring point and recorded as the single-point light spot offset. Y i Complete multi-point synchronous sampling across the entire field to obtain multiple sets of sampled datasets. （X i ,Y i ） ,like Figure 8 As shown; Step S72: Solve for the mean parameter of all measurement points: optical path distance of all measurement points X i Sum the results and divide by the total number of valid measurement points. n The average optical path distance across the entire field is obtained. X ; offset the PSD spot size of all measurement points Y i Sum the results and divide by the total number of valid measurement points. n The average spot offset across the entire field is obtained. ; Calculation formula: ; Step S73: Calculation of single-point deflection angle of the carrier: Based on the principle of small-angle optical approximation, a formula for calculating the single-point deflection angle is constructed to calculate the real-time deflection angle of each measuring point relative to the reference. θ i Calculation formula: ;

[0068] Step S74: Least squares fitting of the reference line: based on the axial travel of the measuring point X i The independent variable is the deflection angle of the measuring point. θ i As the dependent variable, fit the ideal unbiased reference line for the entire field. Solve for the fitted slope a Fitting intercept b ; where the fitting intercept b A fixed zero-bias angle is used to assemble the module, eliminating the inherent initial bias angle of the PSD and ranging hardware installation; fitting slope. a The guide rail's overall tilt angle in the same direction is considered part of the platform installation leveling error. The fitting formula is: ;

[0069] Step S75: Layered elimination of systematic errors: the single-point original deflection angle mentioned above θ i The system errors are compounded by two types of systematic errors: zero deviation in hardware installation and tilt of the overall guide rail installation. These systematic errors need to be removed layer by layer. After removing all installation-related systematic errors, the true deflection angle of the measuring point can be obtained. θ real The formula is as follows:

[0070] Step S76: Calculate the deflection angle and overall straightness. Deflection angle:

[0071] Straightness value:

[0072] The other parts of this embodiment are the same as those in the above embodiments, and will not be described again.

[0073] Example 6: Based on the above embodiments, this embodiment further defines the communication scheme. The communication module on the PCB control board 23 includes a wireless transmission unit and a CAN bus transmission unit, which constitute a redundant communication link. The main control computing module detects the response signal of the wireless transmission link in real time. When the wireless link times out without response, it automatically switches to the CAN bus transmission unit to upload measurement data.

[0074] In industrial workshops, electromagnetic interference from equipment such as motors and frequency converters can occur, and walls and equipment obstructions can also affect wireless signal transmission. Single wireless communication methods are prone to data packet loss and transmission interruption. By using wireless transmission and CAN bus transmission to form a redundant communication link, it can automatically switch to wired CAN communication when the wireless link fails, ensuring stable and reliable output of measurement data and adapting to the needs of complex industrial environments.

[0075] 1. Wireless link determination rules: The device should receive an acknowledgment signal from the host computer every time it sends a signal. If no acknowledgment signal is received within 100ms, the device should resend the data from the CAN bus and then enter wired transmission mode.

[0076] 2. Switch back to wireless: The host computer sends a switch back to wired mode command from the CAN bus. If the device receives a wireless signal response within 100ms, it switches back to wireless mode or restarts the machine.

[0077] The wireless communication frame format is shown in Table 2: Table 2 Wireless Communication Frame Format

[0078] The wired communication frame format is: CAN standard frame, ID 0x321, 8 bytes of data frame from address to linearity data, and no data priority is set.

[0079] The communication module on the PCB control board 23 includes a wireless transmission unit and a CAN bus transmission unit, which together form a redundant communication link; the main control computing module has built-in communication switching logic to detect the response signal of the wireless transmission link in real time.

[0080] The device operates in wireless transmission mode by default. The main control computing module transmits the calculated straightness data outward through the wireless transmission unit and simultaneously starts a timeout timer. If a response frame is received from the host computer within the set timeout period, the wireless link is considered normal, and the wireless transmission mode is maintained. If no response signal is received within the timeout period, the wireless link is considered to have failed, and the main control computing module immediately switches the communication channel and retransmits the current measurement data through the CAN bus transmission unit. When the wireless link stabilizes, it can automatically switch back to wireless transmission mode, realizing dual-link adaptive backup. Other parts of this embodiment are the same as those in the above embodiment and will not be repeated.

[0081] Example 7: This embodiment, based on the above embodiments, further defines the housing structure of the launching device, such as... Figure 1As shown, the first housing 13 has a battery compartment 15 inside, and a first mounting shaft 16 and a protective lens 17 on the outside of the first housing 13. The battery compartment 15 houses the energy storage unit of the first power supply module 14. The first mounting shaft 16 is externally connected to a clamp to fix the emitting device 1. The protective lens 17 covers the light emission window of the laser emitting module 12. The first housing 13 provides mechanical protection and mounting reference for all optical and electrical components of the emitting end, ensuring the relative position accuracy of the internal components. The battery compartment 15 enables the internal and replaceable energy storage unit, supporting cordless portable use of the device. The first mounting shaft 16 is a universal clamp interface that can be quickly adapted to special tooling for different detection scenarios. The protective lens 17, while ensuring high laser transmittance, blocks dust, oil, and splashes from entering the internal optical cavity, preventing lens contamination from affecting the optical path quality.

[0082] The first housing 13 is an integrated rigid housing, with an optical mounting cavity and a battery compartment 15 inside; the laser drive module 11 and the laser emission module 12 are fixedly installed in the optical mounting cavity to ensure the stability of the optical axis position; the energy storage unit of the first power supply module 14 is embedded in the battery compartment 15 and can be removed and replaced through the compartment cover.

[0083] A protective lens 17 is installed at the light-emitting end of the first housing 13. The protective lens 17 completely covers the light-emitting window of the laser emitting module 12. The surface of the lens is coated with an anti-reflection film to reduce laser reflection loss.

[0084] The bottom of the first housing 13 is provided with a first mounting and fixing shaft 16, which is a standard interface structure that can be quickly plugged and fixed with various external tooling such as magnetic clamps, threaded clamps, and guide rail clamps. In field use, the transmitting device 1 is securely mounted on the reference end of the workpiece being measured through the first mounting and fixing shaft 16 to ensure that the position of the transmitting end does not shift during the measurement process. The other parts of this embodiment are the same as those in the above embodiment and will not be described again.

[0085] Example 8: This embodiment further defines the receiving device housing structure based on the above embodiments, such as... Figure 2 , Figure 3As shown, the outer side of the second housing 210 is provided with a charging interface 25, a communication interface 26, a PSD window 27, a ranging window 28, and a second antenna interface 29. The PSD window 27 corresponds to the position of the one-dimensional PSD sensor, and the ranging window 28 corresponds to the position of the laser ranging module 22. Filters are installed on the inner sides of both the PSD window 27 and the ranging window 28 to block ambient stray light from interfering with the detection optical path. The second housing 210 provides integrated installation space for all modules of the receiving end, ensuring the positional accuracy and protection level of the internal optical and circuit components. The PSD window 27 and the ranging window 28 correspond one-to-one with the internal optical components, ensuring normal light incidence. Narrowband filters are installed on the inner sides of the windows to allow only specific wavelengths of laser light to pass through, filtering ambient stray light and significantly improving the device's resistance to ambient light interference. The charging interface 25, communication interface 26, and second antenna interface 29 respectively realize external functional interfaces for power supply and charging, wired communication, and wireless antenna connection.

[0086] The second housing 210 is an integrated rigid housing, and its interior is divided into an optical detection area, a circuit control area, and a power supply area according to function. The PSD receiving and detection module 21 and the laser ranging module 22 are fixedly installed in the optical detection area, and their photosensitive surfaces are respectively aligned with the PSD window 27 and the ranging window 28 on the outside of the housing.

[0087] The inner sides of both the PSD window 27 and the ranging window 28 are equipped with narrowband filters of corresponding wavelengths, which only allow laser light of about 650nm and ranging laser light to pass through, blocking ambient visible light and infrared stray light from entering the photosensitive surface and reducing the interference of ambient light on detection accuracy.

[0088] The second housing 210 has a charging interface 25, a communication interface 26, and a second antenna interface 29 on its side. The charging interface 25 is connected to the second power supply module 24 for charging the battery with an external power source. The communication interface 26 is connected to the CAN bus transmission unit for connecting an external communication cable. The second antenna interface 29 is connected to the wireless transmission unit for connecting an external gain antenna to increase the wireless transmission distance. The other parts of this embodiment are the same as those in the above embodiment and will not be described again.

[0089] Example 9: This embodiment, based on the above embodiments, further defines the power supply system. Both the first and second power supply modules adopt a structure of rechargeable lithium battery packs combined with voltage regulator circuits, possessing overcharge and over-discharge protection functions. After a single full charge, the device can operate continuously for no less than 8 hours. Rechargeable lithium batteries are characterized by high energy density and small size, adapting to the miniaturization design requirements of portable devices. The voltage regulator circuit can eliminate voltage fluctuations during battery depletion, providing a stable operating voltage for each module and preventing voltage fluctuations from causing a decrease in measurement accuracy. The overcharge and over-discharge protection circuits can prevent battery damage from overcharging and over-discharging, extending battery life and improving the safety of device use.

[0090] Both the first power supply module 14 and the second power supply module 24 adopt the architecture of "rechargeable lithium battery pack and voltage regulation management circuit"; the lithium battery pack is a high-capacity rechargeable cell, and the voltage regulation management circuit integrates a voltage regulator chip, a charging management chip, and a battery protection chip.

[0091] When the equipment is working, the voltage output by the lithium battery is converted into the rated operating voltage of each module by the voltage regulator chip to ensure stable power supply voltage across the entire power range. During charging, the charging management chip controls the charging current and voltage. When the battery voltage reaches the upper limit of charging, overcharge protection is triggered, and the charging circuit is automatically cut off. During discharging, the protection chip monitors the battery voltage in real time. When the voltage drops to the lower limit of discharging, over-discharge protection is triggered, and the output circuit is cut off to prevent battery damage.

[0092] After a single full charge, both the transmitting device 1 and the receiving device 2 can operate continuously for no less than 8 hours, which can meet the power requirements for daily on-site testing. The other parts of this embodiment are the same as those in the above embodiments and will not be repeated here.

[0093] Example 10: This embodiment, based on the above embodiments, further includes a mounting calibration frame used in conjunction with the transmitting and receiving devices. The mounting calibration frame, in conjunction with standard calibration equipment, completes the factory zero-point calibration of the device. The main control calculation module stores the zero-bias compensation parameters. Other parts of this embodiment are the same as those in the above embodiments and will not be repeated. Due to the influence of part machining tolerances and optical component assembly tolerances, there is an inherent deviation between the optical zero point and the mechanical zero point at the time of device delivery. This deviation is a fixed systematic error, and if not compensated, it will be directly added to the measurement results, reducing measurement accuracy. By using a mounting calibration frame in conjunction with high-precision standard calibration equipment for factory zero-point calibration, the zero-bias value can be accurately measured, and the compensation parameters are written into the main control calculation module. Error compensation is automatically performed during measurement, ensuring the consistency of measurement accuracy for batch products.

[0094] The device also includes a mounting and calibration frame used in conjunction with the transmitting device 1 and the receiving device 2; the specific implementation process of the factory calibration is as follows: 1. Fix the transmitting device 1 to the reference hole of the standard optical platform using the mounting calibration bracket. Install a plane mirror next to the exit port of the transmitting device 1. Use an autocollimator to vertically illuminate the plane mirror and fine-tune the installation attitude of the transmitting device 1 so that the reflected light coincides with the incident light and the crosshairs of the autocollimator are aligned with the zero point.

[0095] 2. Turn on the laser emission module 12 and install a high-attenuation filter in front of the receiver of the autocollimator to prevent strong light from damaging the autocollimator sensor; finely adjust the emission angle of the laser emission module 12 so that the image of the laser spot on the autocollimator coincides with the zero point, and control the zero deviation within ±5 arcseconds.

[0096] 3. The zero-bias compensation parameters obtained from the calibration are written into the non-volatile memory of the main control calculation module. The device will automatically call these parameters for system error compensation during subsequent measurements. After calibration is completed, the device and calibration mounting frame 3 are shipped together. The other parts of this embodiment are the same as those in the above embodiments and will not be described again.

[0097] Example 11: This embodiment, based on the above embodiments, provides a portable straightness measuring device and its measurement method for use in automotive four-wheel alignment testing. Wheel toe-in is essentially the deflection angle of the wheel's rotation plane relative to the vehicle's longitudinal axis. Its deviation directly affects vehicle stability and tire wear, making it a core testing parameter for automotive four-wheel alignment. In this embodiment, the portable straightness measuring device uses a linear laser beam as a spatial measurement reference. A dedicated wheel clamp enables rapid coaxial clamping between the device and the wheel rim. The wheel toe-in angle is calculated using the laser spot offset and wheel track data, replacing traditional mechanical rulers and string-type measuring tools. This achieves non-contact, high-precision, and automated wheel toe-in testing. The data can be directly synchronized to the host computer at the repair station, improving the efficiency and accuracy of four-wheel alignment repairs.

[0098] The specific process is as follows: 1. Workstation preparation and device clamping: Park the vehicle to be tested in the four-wheel alignment station, keeping the vehicle body straight and the wheels aligned; use a rim clamping special wheel clamp to clamp the transmitting device 1 to the outer reference surface of the rim of the left front wheel of the vehicle, and clamp the receiving device 2 to the corresponding position on the outer side of the rim of the right front wheel of the vehicle using the same clamp; adjust the angle locking mechanism of the clamp to ensure that the device mounting surface is parallel to the wheel rotation plane, and that the linear reference laser beam emitted by the laser transmitting module 12 is projected horizontally along the transverse direction of the vehicle, with the light spot completely incident on the photosensitive surface of the PSD receiving and detection module 21.

[0099] 2. Equipment startup and reference acquisition: Turn on the power to the transmitter 1 and receiver 2. The laser ranging module 22 acquires the lateral optical path distance between the left and right wheels (i.e., the wheel distance reference value) in real time. The PSD receiving and detection module 21 acquires the lateral offset of the line light spot synchronously.

[0100] 3. Multi-point sampling and parameter calculation: Slowly rotate the wheel one revolution and select 4 to 6 sampling points evenly around the wheel circumference. At each point, the optical path distance and spot offset data are collected simultaneously. The main control calculation module combines the distance measurement data and the spot offset to calculate the wheel toe-in angle through geometric calculation. At the same time, it fits the straightness deviation of the wheel's deflection around the entire circumference to eliminate the measurement error caused by the runout of the wheel rim end face and obtain an accurate wheel toe-in value.

[0101] 4. Data Upload and Result Application: After measurement, the communication module on the PCB control board 23 transmits the toe-in parameters and straightness deviation data wirelessly or via CAN bus to the four-wheel alignment host computer system at the repair station, automatically generating a test report. Repair personnel can adjust the tie rod length in real time based on the test data to complete the toe-in calibration. After calibration, the parameters can be measured and verified again until they meet the vehicle's factory standards. Other parts of this embodiment are the same as those in the above embodiments and will not be repeated.

[0102] Example 12: This embodiment, based on the above embodiments, provides a portable straightness measuring device and its measurement method for the inspection of machine tool gantry guideways. The gantry guideway is the core reference for the movement of the machine tool's worktable and spindle; its straightness error directly determines the geometric accuracy of the workpiece, such as its flatness and parallelism, and is a mandatory inspection item for machine tool installation acceptance and periodic calibration. In this embodiment, the device achieves rapid fixation to the guideway using a universal guideway fixture. Using a single-line laser at the transmitting end as the full-length reference, the receiving end moves along the guideway axis to sample multiple points, calculating the full-length straightness error of the guideway. This replaces the cumbersome process of segment-by-segment measurement with a traditional level and manual calculation, significantly improving guideway inspection efficiency and adapting to machine tool calibration and maintenance scenarios in the workshop.

[0103] The specific process is as follows: 1. Fixing the reference end: Clean the surface of the gantry rail to be tested of oil and iron filings. Fix the transmitting device 1 to one end face of the rail to be tested using a universal magnetic rail clamp. Adjust the pitch and deflection angles of the mounting bracket so that the linear reference laser beam emitted by the laser transmitting module 12 is parallel to the longitudinal extension direction of the rail, and the light spot is projected toward the other end of the rail.

[0104] 2. Receiver installation: Install the receiver 2 onto the movable slide of the guide rail using the matching slider clamp, ensuring that the receiver can move smoothly along the guide rail axis with the slide; finely adjust the height and left and right position of the receiver so that the linear laser spot falls completely into the center area of ​​the photosensitive surface of the PSD receiver detection module 21.

[0105] 3. Multi-point sampling throughout the entire travel: After the equipment is powered on and initialized, the operator drives the slide to move at a constant speed along the axial direction of the guide rail, causing the receiving device 2 to move synchronously. Measurement points are arranged at equal intervals along the entire length of the guide rail (one measurement point is set every 500mm on a conventional 5-meter guide rail). Each measurement point is stopped for 1 to 2 seconds, and the laser ranging module 22 and the PSD receiving and detection module 21 synchronously collect the optical path distance and spot offset data at that position, completing the acquisition of multiple sets of data throughout the entire travel.

[0106] 4. Error Calculation and Result Output: After all measurement points are collected, the main control calculation module calls the least squares fitting algorithm to fit the ideal reference straight line of the guide rail, eliminates the systematic errors of zero bias in device installation and overall tilt of the guide rail in layers, calculates the straightness error value of the entire length of the guide rail, and marks the location and direction of the maximum deviation.

[0107] 5. On-site calibration application: Measurement results are uploaded to the machine tool debugging terminal via the communication module, visually displaying the bending deformation of each section of the guide rail. Maintenance personnel can perform targeted calibration operations such as guide rail scraping and shim height adjustment based on the test data. After calibration, retesting and verification are performed until the guide rail straightness meets the machine tool accuracy standards, ensuring the geometric quality of the machined workpiece. Other parts of this embodiment are the same as those in the above embodiments and will not be repeated.

[0108] Example 13: This embodiment, based on the above embodiments, provides a portable straightness measuring device and its measurement method for the application of straightness inspection of large castings. The straightness of the external reference surface of large castings (such as machine tool beds, heavy machine frames, wind turbine bases, etc.) is the core basis for subsequent machining and assembly. Excessive deviation can lead to problems such as stress concentration during assembly and uneven machining allowance. Traditional straightness inspection of large castings requires splicing high-precision straightedges or using large laser trackers, which are cumbersome to operate, costly to use equipment, and have poor on-site adaptability. In this embodiment, the device adapts to the installation reference of large castings by extending the fixing fixture, uses a linear laser as a long-distance measurement reference, and calculates the straightness of the reference surface by multi-point sampling, realizing rapid and low-cost on-site inspection of large castings.

[0109] The specific process is as follows: 1. Workpiece and device setup: Place the large casting stably on the leveling pad at the testing station, and clean the loose sand, burrs and oxide scale from the reference surface to be tested; select an extended support and fixing fixture suitable for large workpieces, fix the transmitting device 1 to one end of the reference surface to be tested, and place the receiving device 2 at the initial position at the other end of the reference surface.

[0110] 2. Optical path alignment adjustment: Adjust the support height and angle fine-tuning mechanism of the extended fixture so that the linear reference laser beam emitted by the laser emitting module 12 is parallel to the length extension direction of the reference surface to be measured, and the light spot is projected longitudinally along the reference surface and completely incident into the photosensitive surface of the PSD receiving and detection module 21; for ultra-large castings with a length of more than 10 meters, the data can be spliced ​​after segment measurement by adding a reflective target in the middle.

[0111] 3. Full-length multi-point sampling: The operator moves the receiving device 2 at a constant speed along the length of the casting reference surface and divides the measurement points evenly according to the total length of the casting; for reference surfaces with high accuracy requirements, the spacing between measurement points is increased; for coarse inspection scenarios, the spacing can be appropriately increased; after the position of each measurement point is stable, the current optical path distance and spot offset data are collected synchronously to complete the full-length sampling.

[0112] 4. Straightness evaluation and judgment: The main control calculation module performs fitting calculations on all measuring point data, eliminates the systematic error caused by the overall installation tilt of the device, and obtains the full-length straightness error of the reference surface to be measured on the casting.

[0113] 5. Application of Test Results: After the measurement data is exported to the testing terminal, it is compared with the straightness tolerance threshold marked on the casting drawing to determine whether the datum surface meets the accuracy requirements of subsequent machining or assembly. For out-of-tolerance areas, the specific location and deviation amount are marked to guide preliminary finishing operations such as welding and grinding, providing accurate datum data for subsequent machining processes. Other parts of this embodiment are the same as those in the above embodiment and will not be repeated.

[0114] Example 14: This embodiment, based on the above embodiments, provides a portable straightness measuring device and its measurement method for application in industrial pipeline straightness testing. Bending deformation of long-distance industrial pipelines and equipment connection pipes increases the resistance to medium transport, causes pipeline stress concentration, and can even lead to leakage and fatigue fracture at connections. Therefore, pipeline straightness is an important indicator for pipeline installation acceptance and regular maintenance inspection. Traditional pipeline straightness testing often uses methods such as string line testing and theodolite testing, which suffer from low measurement efficiency and poor adaptability to outdoor environments. In this embodiment, the device is equipped with a pipeline ring clamp, which can be quickly fixed to the outer wall of the pipeline. The receiving end slides along the pipeline axis to complete multi-point sampling, providing non-contact testing of pipeline bending deformation straightness, making it suitable for complex on-site environments such as outdoor pipe corridors and chemical plant areas.

[0115] The specific process is as follows: 1. Pipeline pretreatment and transmitter fixation: Clean the rust, insulation residue and debris from the outer wall of the pipeline to be tested. Fix the transmitter 1 to the outer wall of one end of the pipeline to be tested using the pipeline ring clamp. Tighten the clamp bolts to ensure that the device does not rotate circumferentially. Adjust the circumferential position of the ring clamp so that the linear reference laser beam emitted by the laser emission module 12 is projected along the axial center direction of the pipeline.

[0116] 2. Receiver installation: Install the receiver 2 onto the pipe using the matching sliding ring clamp. Wear-resistant pulleys are provided on the inner side of the clamp to ensure that the receiver can slide smoothly along the outer wall of the pipe. Fine-tune the radial position of the receiver so that the linear laser spot is aligned with the center of the photosensitive surface of the PSD receiver detection module 21.

[0117] 3. Axial sliding sampling: After the equipment is started, the operator drags the receiving device 2 along the pipeline axis at a uniform speed to set up detection points evenly along the entire length of the pipeline; for long-distance pipelines, sampling can be carried out at a density of one detection point every 2 meters, and the detection points can be densified for key parts such as elbows and flanges; after the position of each detection point is stable, the optical path distance and spot offset data of the current position are collected synchronously to complete the multi-point data collection of the entire pipeline.

[0118] 4. Deformation calculation and anomaly location: The main control calculation module combines the distance and offset data of each measuring point to fit the ideal central axis reference of the pipeline, calculates the straightness error of the bending deformation of the entire pipeline, and identifies the maximum bending position, bending direction and specific bending amount of the pipeline.

[0119] 5. Application of Test Results in Operation and Maintenance: Measurement results are uploaded to the pipeline operation and maintenance testing system via the communication module, serving as the core basis for pipeline installation acceptance and deformation risk early warning. For pipe sections with excessive straightness, maintenance personnel can perform targeted pipeline correction, support and hanger adjustment, and other maintenance operations to eliminate potential pipeline stress hazards and ensure the long-term safety and sealing of the pipeline. Other parts of this embodiment are the same as those in the above embodiments and will not be repeated.

[0120] It is understood that the working principle and process of the portable straightness measuring device structure according to an embodiment of the present invention, such as the housing and power supply module, are existing technologies and are well known to those skilled in the art, and will not be described in detail here.

[0121] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A portable straightness measuring device, characterized in that, It includes a transmitting device (1) and a receiving device (2) that cooperate with each other; The transmitting device (1) includes a first housing (13), which is provided with a laser driving module (11), a laser emitting module (12), and a first power supply module (14). The laser driving module (11) is electrically connected to the laser emitting module (12), and the laser driving module (11) drives the laser emitting module (12) to emit a line reference laser beam. The first power supply module (14) is electrically connected to the laser driving module (11) and the laser emitting module (12) respectively, and provides power to the laser driving module (11) and the laser emitting module (12). The receiving device (2) includes a second housing (210), which houses a PSD receiving and detection module (21), a laser ranging module (22), a PCB control board (23), and a second power supply module (24). The PSD receiving and detection module (21) includes a one-dimensional PSD sensor, which receives the spot of a line reference laser beam emitted by the laser emitting module (12) and outputs an analog electrical signal corresponding to the position of the spot. The laser ranging module (22) includes a transceiver ranging unit, whose ranging optical path is spatially coaxial with the line reference laser beam, and collects the optical path distance between the emitting device (1) and the receiving device (2) in real time. The PCB control board (23) integrates a signal processing module, a main control computing module, and a communication module. The calculation module is connected to the laser ranging module (22) and the signal processing module respectively. The signal processing module converts the analog electrical signal corresponding to the spot position output by the PSD receiving and detection module (21) into a digital signal and transmits it to the main control calculation module. The main control calculation module calculates the straightness error of the workpiece under test based on the digital signal converted by the signal processing module and the optical path distance and spot position signal collected by the laser ranging module (22). The communication module is connected to the main control calculation module and transmits measurement data to the outside. The second power supply module (24) is electrically connected to the PSD receiving and detection module (21), the laser ranging module (22), and the PCB control board (23) respectively, and provides power supply to the PSD receiving and detection module (21), the laser ranging module (22), and the PCB control board (23).

2. The portable straightness measuring device according to claim 1, characterized in that, The PSD receiving and detection module (21) also includes a signal pre-processing unit, which is electrically connected to the one-dimensional PSD sensor. The signal pre-processing unit filters, amplifies, and reduces noise on the analog electrical signal output by the one-dimensional PSD sensor. The signal processing module on the PCB control board (23) has an built-in AD conversion unit. The AD conversion unit converts the analog electrical signal output by the PSD receiving and detection module (21) into a digital signal and then transmits it to the main control computing module.

3. The portable straightness measuring device according to claim 1 or 2, characterized in that, The communication module on the PCB control board (23) includes a wireless transmission unit and a CAN bus transmission unit, which together form a redundant communication link. The main control computing module detects the response signal of the wireless transmission link in real time. When the wireless link times out without response, it automatically switches to the CAN bus transmission unit to upload measurement data.

4. The portable straightness measuring device according to claim 1 or 2, characterized in that, The first housing (13) has a battery compartment (15) inside, and a first mounting and fixing shaft (16) and a protective lens (17) are provided on the outside of the first housing (13). The battery compartment (15) has a built-in energy storage unit of the first power supply module (14), and the first mounting and fixing shaft (16) is connected to an external clamp to fix the emitting device (1). The protective lens (17) covers the light emission window of the laser emitting module (12).

5. The portable straightness measuring device according to claim 1 or 2, characterized in that, The outer side of the second housing (210) is provided with a charging interface (25), a communication interface (26), a PSD window (27), a ranging window (28), and a second antenna interface (29); the PSD window (27) corresponds to the position of the one-dimensional PSD sensor, and the ranging window (28) corresponds to the position of the laser ranging module (22); both the inner sides of the PSD window (27) and the ranging window (28) are equipped with filters, which block ambient stray light from interfering with the detection optical path.

6. The portable straightness measuring device according to claim 1 or 2, characterized in that, It also includes a mounting and calibration frame used in conjunction with the transmitting device (1) and the receiving device (2). The mounting and calibration frame, together with the standard calibration equipment, completes the zero-position calibration of the device at the factory. The main control calculation module stores the zero-bias compensation parameters.

7. A method for measuring straightness using a portable straightness measuring device according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step S1: Fix the transmitting device (1) and the receiving device (2) to the two ends of the workpiece to be measured respectively, and adjust their relative positions so that the reference laser beam emitted by the laser transmitting module (12) is parallel to the axis of the workpiece to be measured. Step S2: Start the transmitting device (1) and the receiving device (2). The laser driving module (11) drives the laser transmitting module (12) to emit a line reference laser beam. The laser ranging module (22) and the PSD receiving and detection module (21) in the receiving device (2) enter the working state. Step S3: Move the receiving device (2) along the axis of the workpiece being measured, and simultaneously collect the analog signal of the light spot position and the optical path distance data at multiple measuring points; Step S4: The signal processing module on the PCB control board (23) converts the analog electrical signal of the spot position output by the PSD receiving and detection module (21) into a digital signal and transmits it to the main control computing module; Step S5: The main control calculation module combines the optical path distance data and the digital signal of the light spot position of each measuring point to calculate the straightness error of the workpiece being measured; Step S6: Transmit the straightness error data to the outside through the communication module on the PCB control board (23).

8. The straightness measurement method according to claim 6, characterized in that, The specific calculation process for the straightness error of the workpiece being measured in step S5 is as follows: The main control calculation module calculates the original deflection angle of each measuring point based on the optical path distance and spot offset of each measuring point; it uses the least squares method to fit the full-field reference line, and layers out the systematic errors caused by the zero offset of hardware installation and the overall tilt of the workpiece to obtain the true deflection angle of each measuring point. The difference between the maximum and minimum values ​​of the true deflection angles at all measuring points is taken as the straightness error of the entire length of the workpiece being measured.

9. The portable straightness measurement method according to claim 7 or 8, characterized in that, The process before step S1 also includes a factory pre-calibration step: The device is calibrated to zero position using a calibration rack and standard calibration equipment. The emission angle of the laser emission module (12) is adjusted to the reference zero position. The zero offset compensation parameters obtained from the calibration are stored in the main control calculation module for system error compensation during the measurement process.

10. The application of the portable straightness measuring device according to any one of claims 1 to 6 or the measuring method according to any one of claims 7 to 9, characterized in that, The application includes at least one of the following: Application 1: The transmitter (1) and receiver (2) are fixed to the wheels on both sides of the vehicle with special wheel clamps to measure the straightness parameters of the wheel toe-in, realize the automated detection and data upload of wheel alignment for passenger cars and commercial vehicles, and carry out four-wheel alignment detection for automobile repair. Application 2: By using a universal fixture fixing device, multiple points are sampled along the gantry guide rail to detect the straightness error of the entire guide rail, ensuring the machining geometric accuracy of the machine tool and performing machine tool gantry guide rail inspection; Application 3: Replace the extended fixture with one suitable for large workpieces to measure the straightness of the outer datum of long castings and perform straightness inspection of large castings; Application 4: When used with a pipe ring clamp, the receiving device (2) is moved along the pipe axis to detect the straightness of the bending deformation of long-distance pipelines and equipment pipelines, and to carry out straightness detection of industrial pipelines.

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