A displacement test sensor test system based on a laboratory environment

Abstract

The application discloses a displacement test sensor test system based on a laboratory environment and belongs to the technical field of sensor test.The application is composed of upper computer software and lower computer hardware.The upper computer software is written by LABVIEW, provides a test man-machine interaction interface, processes and saves collected data, the lower computer hardware includes a motion control module and a test circuit module, the motion control module controls a servo controller by a motion control card to control a servo motor to rotate, and converts the rotary motion of the servo motor into the linear motion of a lead screw by the lead screw, and the test circuit module is powered by a power supply to power a switch array and a displacement test sensor, and measures two-way differential voltage signals by a digital multimeter.The application uses the LABVIEW program to test the displacement test sensor without adjusting the distance between the sensor and the magnetic grating ruler, simplifies complicated steps, saves time and improves efficiency.

Description

Technical Field

[0001] This invention relates to the field of sensor testing technology, specifically to a displacement testing sensor testing system based on a laboratory environment. Background Technology

[0002] Compared to traditional Hall effect sensors, linear position sensors based on the AMR principle offer higher positional accuracy and can tolerate significant variations in the distance between the sensor and the magnet, providing greater installation flexibility. Through optimized design and packaging, AMR linear position sensors can operate in harsh environments such as those with oil, dust, and high temperatures, exhibiting excellent reliability and accuracy. AMR linear position sensors can be used with a series of magnetic scales with varying pole spacing. When the magnetic scale shifts, the AMR linear position sensor detects the change in magnetic field and outputs different signals. By processing these signals, position measurement can be achieved. Furthermore, the sensor itself spans one or more magnetic poles, eliminating positional errors introduced by imperfect magnetic poles and further improving measurement accuracy.

[0003] During the development of AMR linear position sensors, repeated testing and verification of their linear position accuracy are necessary to ensure high precision and consistency. Because AMR linear position sensors are niche, specialized components, there are no readily available, universally applicable testing devices. Furthermore, the distance required for the magnetic scale used with linear position sensors of different accuracies varies during testing. Traditional testing methods involve placing the AMR linear position sensor on a fixed fixture, requiring manual distance adjustment and zeroing calibration before testing for sensors of varying accuracies, making the process complex. Summary of the Invention

[0004] The purpose of this invention is to provide a displacement testing sensor testing system based on a laboratory environment, in order to solve the problem mentioned in the background art that the operation of AMR linear sensors is complicated when testing displacement testing sensors of different accuracies because AMR linear sensors are niche components.

[0005] To address the aforementioned technical problems, the present invention provides the following technical solution: a displacement testing sensor testing system based on a laboratory environment.

[0006] The system includes a host computer software component and a slave computer hardware component;

[0007] The host computer software is programmed using LabVIEW, providing a human-computer interaction interface for testing. The program records the position information of the displacement test sensor and the differential voltage output by the sensor corresponding to the sensor position information. It calculates the position accuracy and repeatability of the displacement test sensor and finally saves both the original data and the calculated data in tabular form. The original data is the position information of the displacement test sensor and the differential voltage output by the sensor corresponding to the sensor position information, and the calculated data is the position accuracy and repeatability of the displacement test sensor.

[0008] The lower-level hardware includes a motion control module and a test circuit module;

[0009] The motion control module uses a control card and a servo controller to control the servo motor, which generates the required quantitative displacement according to the test requirements; different motion step lengths and total distances are selected based on the different displacement test sensors.

[0010] The test circuit module supplies power to the switch array and the displacement sensor under test, and measures the differential voltage output of the displacement sensor under test.

[0011] The output of the test circuit module is connected to the input of the motion control module.

[0012] The motion control module includes a motion control card unit, a servo controller unit, a servo motor unit, and a fixture unit;

[0013] The motion control card unit is a high-performance servo motor motion control card that utilizes a high-performance microprocessor and large-scale programmable devices to achieve multi-axis coordinated control of servo motors by multiple servo controllers. It includes functions such as pulse output, pulse counting, digital input, digital output, and D / A output. It can emit continuous, high-frequency pulse trains, controlling the motor speed by changing the frequency of the emitted pulses and controlling the motor position by changing the number of emitted pulses. Its pulse output modes include pulse / direction and pulse / pulse. Pulse counting can be used for encoder position feedback, providing accurate machine position and correcting errors generated during transmission. The motion control card determines the actual position of the fixture by reading the position signal fed back from the servo controller.

[0014] The servo controller unit uses a digital signal processor (DSP) as its control core, enabling the implementation of complex control algorithms. The power devices employ a drive circuit designed around an intelligent power module (IPM). The IPM integrates the drive circuit and includes fault detection and protection circuits for overvoltage, overcurrent, overheating, and undervoltage. A soft-start circuit is also added to the main circuit to reduce the impact on the driver during startup. The power drive unit first rectifies the input three-phase power or mains power through a three-phase full-bridge rectifier circuit to obtain the corresponding DC power. The rectified three-phase power or mains power is then frequency-converted by a three-phase sinusoidal PWM voltage-type inverter to drive the three-phase permanent magnet synchronous AC servo motor. In the servo controller's speed closed loop, the real-time speed measurement accuracy of the motor rotor is crucial for improving the dynamic and static characteristics of the speed loop's speed control. To achieve a balance between measurement accuracy and system cost, an incremental photoelectric encoder is generally used as the speed sensor, and the commonly used speed measurement method is the M / T speed measurement method. While the M / T speed measurement method offers a certain level of accuracy and a relatively wide measurement range, it has inherent drawbacks, primarily: a) at least one complete encoder pulse must be detected within the measurement cycle, limiting the minimum measurable speed; b) the timer switches of the two control systems used for speed measurement are difficult to keep strictly synchronized, compromising measurement accuracy in situations with significant speed variations. Therefore, traditional speed loop designs using this method struggle to improve the speed tracking and control performance of servo controllers.

[0015] The servo motor unit is the engine that controls the operation of mechanical components in the servo system; it is an auxiliary motor indirect speed change device. The servo motor can control speed with very high positional accuracy, converting voltage signals into torque and speed to drive the controlled object. The servo motor rotor speed is controlled by the input signal and can respond quickly. In automatic control systems, it is used as an actuator and has characteristics such as a small electromechanical time constant and high linearity. It can convert received electrical signals into angular displacement or angular velocity output on the motor shaft. The servo controller and servo motor operate in a closed-loop control system. The servo motor provides real-time feedback of its current rotational position to the servo controller. After receiving the feedback signal, if the required control position differs from the feedback position, the servo controller will automatically adjust the motor to ensure the control position matches the feedback position.

[0016] The clamping unit includes clamp one and clamp two;

[0017] The fixture is equipped with a lead screw, an optical encoder and a magnetic scale to realize closed-loop control of the servo controller in linear movement. At the same time, when the lead screw moves in a linear motion, it will drive the magnetic scale to move.

[0018] The second fixture is equipped with a displacement test sensor. Under the control of the servo controller, the distance between the displacement sensor and the magnetic scale can be precisely controlled. The servo motor can be automatically adjusted to adjust the test distance by using a program written on the host computer.

[0019] The lead screw is used to convert the rotary motion of the servo motor into linear motion. The lead screw is connected to the servo motor, and the servo motor drives a pair of lead screw nuts after being reduced by gears. The forward and reverse rotation of the servo motor completes the push rod action, thus converting the rotary motion of the servo motor into linear motion.

[0020] The optical encoder is a sensor that converts the mechanical geometric displacement on the output shaft into pulses or digital signals through photoelectric conversion. It consists of a light source, a code disk, and a photosensitive element. The grating is essentially a disk engraved with regularly spaced transparent and opaque lines. The luminous flux received by the photosensitive element changes synchronously with these lines. The output waveform of the photosensitive element is shaped into a pulse signal, outputting one pulse per revolution. Based on the pulse changes, the displacement of the equipment can be accurately measured and controlled. To reduce mechanical errors introduced during the lead screw's machining process, an optical encoder needs to be installed on the lead screw. Simultaneously, the servo controller's control mode is changed to a fully closed-loop mode. This allows the servo controller to use the feedback signal from the optical encoder as a reference, thus achieving closed-loop control in linear motion.

[0021] The magnetic scale consists of a magnetic scale and a reading head. The magnetic scale is an important component of the magnetic scale displacement sensor, providing a reference for sensor displacement measurement and position positioning. The magnetic scale has the following advantages: high durability, easy installation, strong anti-interference, strong impact resistance, and is not easily affected by vibration, dust, scale, or oil.

[0022] The test circuit module includes a power supply unit, a digital multimeter unit, and a switch array unit;

[0023] The power supply unit provides power to the switch array and the displacement test sensor under test.

[0024] The digital multimeter unit is used to test the differential voltage output of the displacement test sensor under test; by changing the power supply voltage, the differential voltage output by the displacement test sensor under different voltages can be measured; both the selected power supply and the digital multimeter support programmable instrument standard commands, and the host computer software can realize the control function of these instruments and devices through GPIB or USB communication interface.

[0025] The switch array unit communicates via an IIC interface and a PC interface to enable a digital multimeter to measure two differential voltage signals. The array can provide up to 4x4 switches, with each switch node being a double-pole double-throw switch.

[0026] The IIC interface is a standard bidirectional transmission interface. A single data transmission requires the host and slave to follow the IIC protocol standard.

[0027] The two differential voltage signals are the position-related sine and cosine signals output by the two Wheatstone bridges of the sensor. Since the internal layout of the Wheatstone bridge matches the magnetic pole spacing of the magnetic scale, when the sensor moves along the magnetic scale, the two bridges will output position-related sine and cosine signals respectively, and the output sine and cosine signals will form two differential signals.

[0028] Compared with existing technologies, the beneficial effects achieved by this invention are as follows: This invention utilizes an automated LabVIEW platform program, eliminating the need to adjust the distance between the displacement sensor and the magnetic scale during displacement testing. It integrates cumbersome steps, achieving position control and sensor output signal acquisition with a single click, saving testing time and improving efficiency. The system has two servo systems, allowing adjustment of relative position in two directions. A switch array is introduced, connecting to an IIC interface and a PC interface to enable measurement of multiple signals using a single digital multimeter. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0030] Figure 1 This is a schematic diagram of the structure of a displacement testing sensor testing system based on a laboratory environment according to the present invention;

[0031] Figure 2 This is a schematic diagram of the motion control module of the lower-level hardware part of a displacement testing sensor testing system based on a laboratory environment according to the present invention.

[0032] Figure 3 This is a schematic diagram of the test circuit module of the lower-level hardware part of a displacement testing sensor testing system based on a laboratory environment according to the present invention;

[0033] Figure 4 This is a schematic diagram of the bridge section of the displacement test sensor and the output waveform of the bridge in a displacement test sensor test system based on a laboratory environment according to the present invention.

[0034] Figure 5 This is a schematic diagram of the host computer software program interface in a displacement testing sensor testing system based on a laboratory environment according to the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Please see Figures 1-5 The present invention provides a technical solution: a displacement testing sensor testing system based on a laboratory environment.

[0037] The system includes a host computer software component and a slave computer hardware component;

[0038] The host computer software is programmed using LabVIEW, providing a human-computer interaction interface for testing. The program records the displacement test sensor's position information and the corresponding differential voltage output by the sensor. It calculates the position accuracy and repeatability of the displacement test sensor, and finally saves both the original data and the calculated data in tabular form. The original data consists of the displacement test sensor's position information and the corresponding differential voltage output by the sensor. The calculated data consists of the displacement test sensor's position accuracy and repeatability.

[0039] The lower-level hardware includes a motion control module and a test circuit module;

[0040] The motion control module uses a control card and a servo controller to control the servo motor, which generates the required quantitative displacement according to the test requirements; different motion step lengths and total distances are selected based on the different displacement test sensors.

[0041] The test circuit module supplies power to the switch array and the displacement sensor under test, and measures the differential voltage output of the displacement sensor under test.

[0042] The output of the test circuit module is connected to the input of the motion control module.

[0043] The motion control module includes a motion control card unit, a servo controller unit, a servo motor unit, and a fixture unit;

[0044] The motion control card unit is a high-performance servo motor motion control card that utilizes a high-performance microprocessor and large-scale programmable devices to achieve multi-axis coordinated control of servo motors by multiple servo controllers. It includes functions such as pulse output, pulse counting, digital input, digital output, and D / A output. It can emit continuous, high-frequency pulse trains, controlling the motor speed by changing the frequency of the emitted pulses and controlling the motor position by changing the number of emitted pulses. Its pulse output modes include pulse / direction and pulse / pulse. Pulse counting can be used for encoder position feedback, providing accurate machine position and correcting errors generated during transmission. The motion control card determines the actual position of the fixture by reading the position signal fed back from the servo controller.

[0045] The servo controller unit uses a digital signal processor (DSP) as its control core, enabling the implementation of complex control algorithms. The power devices employ a drive circuit designed around an intelligent power module (IPM). The IPM integrates the drive circuit and includes fault detection and protection circuits for overvoltage, overcurrent, overheating, and undervoltage. A soft-start circuit is also added to the main circuit to reduce the impact on the driver during startup. The power drive unit first rectifies the input three-phase power or mains power through a three-phase full-bridge rectifier circuit to obtain the corresponding DC power. The rectified three-phase power or mains power is then frequency-converted by a three-phase sinusoidal PWM voltage-type inverter to drive the three-phase permanent magnet synchronous AC servo motor. In the servo controller's speed closed loop, the real-time speed measurement accuracy of the motor rotor is crucial for improving the dynamic and static characteristics of the speed loop's speed control. To achieve a balance between measurement accuracy and system cost, an incremental photoelectric encoder is generally used as the speed sensor, and the commonly used speed measurement method is the M / T speed measurement method. While the M / T speed measurement method offers a certain level of accuracy and a relatively wide measurement range, it has inherent drawbacks, primarily: a) at least one complete encoder pulse must be detected within the measurement cycle, limiting the minimum measurable speed; b) the timer switches of the two control systems used for speed measurement are difficult to keep strictly synchronized, compromising measurement accuracy in situations with significant speed variations. Therefore, traditional speed loop designs using this method struggle to improve the speed tracking and control performance of servo controllers.

[0046] The servo motor unit is the engine that controls the operation of mechanical components in the servo system; it is an auxiliary motor indirect speed change device. The servo motor can control speed with very high positional accuracy, converting voltage signals into torque and speed to drive the controlled object. The servo motor rotor speed is controlled by the input signal and can respond quickly. In automatic control systems, it is used as an actuator and has characteristics such as a small electromechanical time constant and high linearity. It can convert received electrical signals into angular displacement or angular velocity output on the motor shaft. The servo controller and servo motor operate in a closed-loop control system. The servo motor provides real-time feedback of its current rotational position to the servo controller. After receiving the feedback signal, if the required control position differs from the feedback position, the servo controller will automatically adjust the motor to ensure the control position matches the feedback position.

[0047] The clamping unit includes clamp one and clamp two;

[0048] The fixture is equipped with a lead screw, an optical encoder and a magnetic scale to realize closed-loop control of the servo controller in linear movement. At the same time, when the lead screw moves in a linear motion, it will drive the magnetic scale to move.

[0049] The second fixture is equipped with a displacement test sensor. Under the control of the servo controller, the distance between the displacement sensor and the magnetic scale can be precisely controlled. The servo motor can be automatically adjusted to adjust the test distance by using a program written on the host computer.

[0050] The lead screw is used to convert the rotary motion of the servo motor into linear motion. The lead screw is connected to the servo motor, and the servo motor drives a pair of lead screw nuts after being reduced by gears. The forward and reverse rotation of the servo motor completes the push rod action, thus converting the rotary motion of the servo motor into linear motion.

[0051] The optical encoder is a sensor that converts the mechanical geometric displacement on the output shaft into pulses or digital signals through photoelectric conversion. It consists of a light source, a code disk, and a photosensitive element. The grating is essentially a disk engraved with regularly spaced transparent and opaque lines. The luminous flux received by the photosensitive element changes synchronously with these lines. The output waveform of the photosensitive element is shaped into a pulse signal, outputting one pulse per revolution. Based on the pulse changes, the displacement of the equipment can be accurately measured and controlled. To reduce mechanical errors introduced during the lead screw's machining process, an optical encoder needs to be installed on the lead screw. Simultaneously, the servo controller's control mode is changed to a fully closed-loop mode. This allows the servo controller to use the feedback signal from the optical encoder as a reference, thus achieving closed-loop control in linear motion.

[0052] The magnetic scale consists of a magnetic scale and a reading head. The magnetic scale is an important component of the magnetic scale displacement sensor, providing a reference for sensor displacement measurement and position positioning. The magnetic scale has the following advantages: high durability, easy installation, strong anti-interference, strong impact resistance, and is not easily affected by vibration, dust, scale, or oil.

[0053] The test circuit module includes a power supply unit, a digital multimeter unit, and a switch array unit;

[0054] The power supply unit provides power to the switch array and the displacement test sensor under test.

[0055] The digital multimeter unit is used to test the differential voltage output of the displacement test sensor under test; by changing the power supply voltage, the differential voltage output by the displacement test sensor under different voltages can be measured.

[0056] The switch array unit communicates via an IIC interface and a PC interface to enable a digital multimeter to measure two differential voltage signals. The array can provide up to 4x4 switches, with each switch node being a double-pole double-throw switch.

[0057] The two differential voltage signals are the position-related sine and cosine signals output by the two Wheatstone bridges of the sensor. Since the internal layout of the Wheatstone bridge matches the magnetic pole spacing of the magnetic scale, when the sensor moves along the magnetic scale, the two bridges will output position-related sine and cosine signals respectively, and the output sine and cosine signals will form two differential signals.

[0058] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0059] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A displacement test sensor test system based on a laboratory environment, characterized in that, The system comprises a host computer software part and a lower computer hardware part; The host computer software part is programmed by using LABVIEW, and provides a test man-machine interaction interface; the program records position information of a displacement test sensor and differential voltage output by the sensor corresponding to the position information; the position accuracy and the repeat accuracy of the displacement test sensor are obtained by calculation; finally, the original data and the calculated data are kept in table form. The lower computer hardware part comprises a motion control module and a test circuit module. The motion control module comprises a motion control card unit, a servo controller unit, a servo motor unit and a clamp unit; the motion control module controls the servo motor by using the control card and the servo controller to generate the required quantitative displacement according to the test requirements; different motion steps and total distances are selected according to different displacement test sensors; the servo motor unit converts the voltage signal transmitted by the servo controller into torque and speed to drive; the servo controller and the servo motor are a common position control combination, and the position control is accurate; the servo controller and the servo motor are in closed-loop control, and the servo motor feeds back the current rotation position to the servo controller in real time; after obtaining the feedback signal, the servo controller automatically adjusts the motor to make the control position consistent with the feedback position. The test circuit module supplies power to the switch array and the tested displacement test sensor and measures the differential voltage output by the tested displacement test sensor; the test circuit module comprises a power supply unit, a digital multimeter unit and a switch array unit; the power supply unit supplies power to the switch array and the tested displacement test sensor; the digital multimeter unit is used for testing the differential voltage output by the tested displacement test sensor; by changing the power supply voltage, the differential voltage output by the displacement test sensor under different voltages can be measured; the switch array unit communicates with the PC interface through the IIC interface to realize the function of measuring two differential voltage signals by one digital multimeter; the two differential voltage signals are the position-related sine signal and cosine signal output by the two Wheatstone bridges of the sensor respectively; since the layout inside the Wheatstone bridge is matched with the magnetic pole spacing of the magnetic grating ruler, when the sensor moves along the magnetic grating ruler, the two bridges output the position-related sine signal and cosine signal respectively; the output sine signal and cosine signal form two differential signals. The output end of the test circuit module is connected with the input end of the motion control module.

2. A lab-environment-based displacement test sensor test system according to claim 1, wherein: The motion control module comprises a motion control card unit, a servo controller unit, a servo motor unit and a clamp unit; The motion control card unit uses high-performance microprocessors and large-scale programmable devices to realize multi-axis coordinated control of the servo motor by the servo controller; the actual position of the clamp is judged by reading the position signal fed back by the servo controller.

3. A lab-environment-based displacement test sensor test system according to claim 2, wherein: The servo controller unit is a kind of controller for controlling servo motor, and the servo controller controls the servo motor through position, speed and torque, so as to realize high-precision positioning of transmission system.

4. A lab environment based displacement test sensor test system according to claim 2, wherein: The clamp unit comprises a clamp one and a clamp two; The clamp one is equipped with a lead screw, an optical encoder and a magnetic grating ruler, so as to realize closed-loop control of the servo controller on linear movement, and the lead screw drives the magnetic grating ruler to displace when moving linearly; The clamp two is installed with a displacement test sensor, and through the control of the servo controller, the distance between the measured displacement sensor and the magnetic grating ruler can be accurately controlled, and through the program writing of the upper computer, the servo motor can be automatically adjusted to test the distance.

5. A lab-environment-based displacement test sensor test system according to claim 4, wherein: The lead screw is used to convert the rotary motion of the servo motor into linear motion, and the lead screw is connected with the servo motor, the servo motor drives a pair of lead screw nuts after gear deceleration, and the rotary motion of the servo motor is changed into linear motion through the forward and reverse rotation of the servo motor.

6. A lab environment based displacement test sensor test system according to claim 4, wherein: The optical encoder is a kind of sensor for converting the mechanical geometric displacement of the output shaft into pulse or digital through photoelectric conversion, and in order to reduce the mechanical error introduced by the lead screw in the machining process, the optical encoder needs to be installed on the lead screw, and at the same time, the control mode of the servo controller is changed to full closed loop mode, so that the servo controller will take the feedback signal of the optical encoder as the reference, so as to realize the closed loop of the servo controller on linear movement.

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