High-precision LVDT contact type displacement sensor

Abstract

The embodiment of the invention provides a high-precision LVDT contact type displacement sensor which comprises a main control module, a man-machine module and a measurement module, the man-machine module and the measurement module are electrically connected with the main control module, and the measurement module comprises an inductance unit and a signal processing unit electrically connected with the output end of the inductance unit; the inductance unit adopts an inductance coil and an armature which are coupled with each other as generating elements of electromagnetic induction so as to detect a complete displacement signal; the signal processing unit receives the electromagnetic induction signal and carries out modulation processing, filtering processing and amplification detection processing on the received signal. The digital separation type contact displacement sensor has the advantages of being high in detection precision, user-friendly in use and the like.

Description

Technical Field

[0001] The invention relates to the technical field of displacement measurement sensors, in particular to a high-precision LVDT contact displacement sensor. Background Art

[0002] Displacement sensors have always been known for their high precision in the field of measurement technology. The function of the sensor is to convert various measured physical quantities into electrical quantities. In the production process, displacement measurement is generally divided into two types: measuring physical size and mechanical displacement.

[0003] The inductive displacement sensor in the prior art uses electrical components to convert mechanical displacement into a resistance or voltage output that is linearly or functionally related to the mechanical displacement. In the process of receiving the detection signal, since the detection of the inductive coil is easily affected by the external magnetic field, the armature 1 needs to move to trigger the operation of the inductive coil, resulting in data delay in the measurement process, making the measurement result inconsistent with the actual result, which has a certain impact on the measurement accuracy of the sensor. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problems and provide a high-precision LVDT contact displacement sensor, which can make the signal processing process more rigorous through the combination design of circuits, reduce data errors in the conversion process, perform high-precision conversion of the relative displacement generated between the electrical component and the object to be measured, and improve the detection accuracy.

[0005] To achieve the above-mentioned purpose, the present invention provides a high-precision LVDT contact displacement sensor, comprising a main control module, a human-machine module and a measuring module, wherein the human-machine module and the measuring module are electrically connected to the main control module respectively, and the measuring module comprises an inductance unit and a signal processing unit electrically connected to the output end of the inductance unit; the inductance unit adopts mutually coupled inductance coils and armatures as generating elements of electromagnetic induction to detect a complete displacement signal; the signal processing unit receives the electromagnetic induction signal and performs modulation processing, filtering processing and amplification and detection processing on the received signal.

[0006] Preferably, the signal processing unit includes a detection power supply circuit, and a 32-bit high-speed microprocessor, an amplification and detection circuit, a filtering circuit, a differential analog synchronous modulator, a frequency division circuit, and a low-pass filtering circuit, which are respectively electrically connected to the detection power supply circuit; the 32-bit high-speed microprocessor is respectively electrically connected to the amplification and detection circuit and the differential analog synchronous modulator; the differential analog synchronous modulator is respectively electrically connected to the frequency division circuit, the filtering circuit and the inductance unit; the low-pass filtering circuit is respectively electrically connected to the inductance unit and the frequency division circuit; and the filtering circuit is electrically connected to the amplification and detection circuit.

[0007] Preferably, the inductance unit includes an armature, a primary winding, and a secondary winding coupled to the primary winding, the primary winding is energized to trigger an excitation signal for displacement detection, the secondary winding receives the excitation signal and undergoes electromagnetic induction with the armature, and the primary winding and the secondary winding are electrically connected to the low-pass filter circuit and the differential analog synchronous modulator, respectively.

[0008] Preferably, the inductor unit further comprises a contact head, and one end of the armature is fixedly connected to the contact head.

[0009] Preferably, the main control module includes a main control power supply unit, and a 32-bit high-speed microprocessor, a communication unit and a transmission control unit respectively electrically connected to the main control power supply unit; the communication unit and the transmission control unit are respectively electrically connected to the 32-bit high-speed microprocessor, and the human-machine module is electrically connected to the main control power supply unit.

[0010] Preferably, the communication unit is an RS485 communication circuit.

[0011] Preferably, the transmission control unit includes an NPN / PNP input / output control circuit and a surge voltage absorption circuit electrically connected to the NPN / PNP input / output control circuit, the surge voltage absorption circuit is electrically connected to the main control power supply unit, and the NPN / PNP input / output control circuit is electrically connected to a 32-bit high-speed microprocessor.

[0012] Preferably, the human-machine module includes an 8-bit microprocessor, a storage unit, an operation unit, and a display unit, which are respectively electrically connected to the main control power supply unit; the storage unit, the operation unit, and the display unit are respectively electrically connected to the 8-bit microprocessor, and the 8-bit microprocessor is electrically connected to the 32-bit high-speed microprocessor.

[0013] Preferably, it is characterized in that the 32-bit high-speed microprocessor is STM32F401CEU6 or STM32F401RET6.

[0014] Preferably, the 8-bit microprocessor is PIC16F722.

[0015] According to the high-precision LVDT contact displacement sensor of the present invention, through the inductance unit and the signal processing unit with special inductance, the sensor can activate electromagnetic induction through the excitation signal during the detection process, making the signal reception active. Specifically, the primary winding sends out the excitation signal, and the secondary winding receives the detection signal. Under the influence of the excitation signal, the generated signal is transmitted to the signal processing unit, so that the secondary winding can completely receive the induced current generated by the armature change, avoid the detection omission of small displacement of the object being measured, and improve the detection accuracy.

[0016] Furthermore, through the signal processing unit set inside the sensor, the generated displacement signal is modulated, filtered, amplified and detected, so that the displacement signal can be highly filtered. The generated electrical signal is completely converted into a 12-bit high-precision digital signal consistent with the actual displacement through a 32-bit high-precision and high-speed displacement sensor. Finally, the digital signal is converted into a displacement amount and displayed on a display screen, thereby improving detection accuracy and enhancing user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 A system block diagram of a sensor circuit according to an embodiment of the present application;

[0019] Figure 2 For this application Figure 1 System block diagram of the signal processing unit;

[0020] Figure 3 For this application Figure 1 The circuit schematic diagram of the signal processing unit;

[0021] Figure 4 For this application Figure 1 The circuit schematic diagram of the detection power supply circuit;

[0022] Figure 5 For this application Figure 1 System block diagram of the main control module;

[0023] Figure 6 For this application Figure 1 Pin diagram of 32-bit high-speed microprocessor;

[0024] Figure 7 For this application Figure 1 The circuit schematic diagram of the main control power supply unit;

[0025] Figure 8 For this application Figure 1 The circuit schematic diagram of the communication unit;

[0026] Fig. 9 For this application Figure 1 Circuit diagram of overcurrent protection circuit;

[0027] Fig.10 For this application Figure 1 System block diagram of the human-machine module;

[0028] Fig.11 For this application Figure 1The circuit schematic diagram of the human-machine interface module;

[0029] Fig.12 For this application Figure 1 The circuit schematic diagram of the storage unit in FIG.

[0030] Description of reference numerals: 1 - armature, 2 - primary winding, 3 - secondary winding, 4 - contact head. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0032] Example: Reference Figure 1 As shown, a high-precision LVDT contact displacement sensor includes a main control module, a human-machine module and a measurement module, wherein the human-machine module and the measurement module are electrically connected to the main control module. The measurement module sends the detected data to the main control module for data analysis, and the operator realizes human-machine interaction with the displacement sensor through the human-machine module.

[0033] Specifically, the measurement module includes an inductance unit and a signal processing unit electrically connected to the output end of the inductance unit; the inductance unit uses a mutually coupled inductance coil and an armature as a generating element of electromagnetic induction to detect a complete displacement signal; the signal processing unit receives the electromagnetic induction signal and performs modulation processing, filtering processing, and amplification and detection processing on the received signal. By setting the mutually coupled inductance coil as the generating element of electromagnetic induction, the signal processing unit can completely receive the induced current generated by the armature change, avoid missing the detection of small displacements of the measured object, and improve the detection accuracy.

[0034] As a preferred implementation of this embodiment, refer to Figure 2 , Figure 3 As shown, the signal processing unit includes a detection power supply circuit, and a 32-bit high-speed microprocessor, an amplification detection circuit, a filtering circuit, a differential analog synchronous modulator, a frequency division circuit, and a low-pass filtering circuit, which are respectively electrically connected to the detection power supply circuit. The 32-bit high-speed microprocessor is respectively electrically connected to the amplification detection circuit and the differential analog synchronous modulator, the differential analog synchronous modulator is respectively electrically connected to the frequency division circuit, the filtering circuit and the inductance unit, the low-pass filtering circuit is respectively electrically connected to the inductance unit and the frequency division circuit, and the filtering circuit is electrically connected to the amplification detection circuit.

[0035] In this embodiment, the differential analog synchronous modulator is used to divide the frequency of the constant square wave, the displacement analog signal is modulated and demodulated to eliminate the noise interference signal, and the amplification detection and filtering circuit is used to convert the displacement AC signal into a corresponding DC signal and filter out the interference signal. The low-pass filter circuit is electrically connected to the primary winding and is used to convert the square wave signal emitted by the primary winding into a sinusoidal signal. Figure 4As shown, the detection power supply circuit is a voltage-stabilized power supply circuit, and its main features include wide voltage input DC12V-DC24V, power input polarity reverse connection protection and input surge voltage absorption circuit. The 32-bit high-speed microprocessor is any microprocessor with the following features: a built-in high-precision high-speed 12-bit ADC converter, high-speed data computing capability, and multi-task real-time processing capability. In this embodiment, the 32-bit microprocessor in the signal processing unit is preferably STM32F401CEU6, and its packaging standard is LQFP48 (7×7mm).

[0036] In this embodiment, review Figure 1 The inductance unit includes an armature 1, a primary winding 2, and a secondary winding 3 coupled with the primary winding. The primary winding 2 is energized to trigger an excitation signal for displacement detection. The secondary winding 3 receives the excitation signal and generates electromagnetic induction with the armature 1. The primary winding 2 and the secondary winding 3 are electrically connected to a low-pass filter circuit and a differential analog synchronous modulator, respectively. The inductance unit also includes a contact head 4, and one end of the armature 1 is fixedly connected to the contact head 4. When the sensor performs detection, the primary winding 2 is energized to trigger an excitation signal, the tail of the sensor remains stationary, and the contact head 4 contacts the object to be measured. When the contact surface is uneven, the armature 1 moves. During the movement of the armature 1, the secondary winding 3 receives the electromagnetic signal due to the electromagnetic induction effect.

[0037] As a preferred implementation of this embodiment, refer to Figure 5 and Figure 6 As shown, the main control module includes a main control power supply unit, and a 32-bit high-speed microprocessor, a communication unit and a transmission control unit electrically connected to the main control power supply unit respectively. The communication unit and the transmission control unit are electrically connected to the 32-bit high-speed microprocessor respectively, and the human-machine module is electrically connected to the main control power supply unit. Figure 1 and 7 As shown, the main control power supply unit includes a power supply circuit, a power reverse polarity protection circuit and a surge voltage absorption circuit, which are used to output a stable power supply so that the sensor works stably. Among them, the 32-bit high-speed microprocessor is any microprocessor with the following characteristics, namely, a built-in high-precision high-speed 12-bit ADC converter, high-speed data computing capability and multi-task real-time processing capability. In this embodiment, the 32-bit microprocessor in the main control module is preferably STM32F401RET6, and its packaging standard is LQFP64 (10×10mm).

[0038] The communication unit is a communication circuit that is obvious to those skilled in the art. Preferably, the present embodiment uses Figure 8 The RS485 communication circuit shown.

[0039] In this embodiment, reference Fig. 9As shown, the transmission control unit includes an NPN / PNP input / output control circuit, a surge voltage absorption circuit electrically connected to the NPN / PNP input / output control circuit, the surge voltage absorption circuit is electrically connected to the main control power supply unit, and the transmission control unit is used for overcurrent protection and surge voltage absorption to protect the input and output circuits. The transmission control unit includes an NPN / PNP input / output control circuit, a surge voltage absorption circuit electrically connected to the NPN / PNP input / output control circuit, the surge voltage absorption circuit is electrically connected to the main control power supply unit, and the NPN / PNP input / output control circuit is electrically connected to a 32-bit high-speed microprocessor.

[0040] In this embodiment, reference Fig.10 and Fig.11 As shown, the human-machine module includes an 8-bit microprocessor, a storage unit, an operation unit, and a display unit, which are electrically connected to the main control power supply unit respectively. The storage unit, the operation unit, and the display unit are electrically connected to the 8-bit microprocessor respectively, and the 8-bit microprocessor is electrically connected to the 32-bit high-speed microprocessor. In this embodiment, the operation unit is a 6-bit keyboard, and the display unit is a multi-color LED display or a multi-color digital tube. Fig.12 As shown, SCL1 and CDL1 of the storage unit are connected to pins 58 and 59 of STM32F401RET6 respectively.

[0041] The man-machine module is managed by an independent microprocessor and is provided with two-color LED indicators for distinguishing each function. The storage unit is any memory for storing set parameters and capable of 1 million times of erasing and writing. The display unit is a 7-segment LED digital alphanumeric display tube. The operation unit is a 6-button operation unit, and the key lock function is realized by pressing the button. The 6-button operation unit has humanized characteristics. With the LED light and the digital tube display, the operator can clearly understand the working status and detection parameters of the sensor, thereby improving the user experience. The storage unit, the operation unit, the display unit, and the 8-bit microprocessor are electrically connected to the power supply unit, respectively, and the 8-bit microprocessor is electrically connected to the main control module. Preferably, the 8-bit microprocessor is PIC16F722, and its packaging standard is QFN28. In this embodiment, the man-machine module is powered by the power circuit of the main control module. In the structural design, the split mechanical structure design of the man-machine module and the main control module can be carried out by cable connection. The use of cables has faster and more stable performance in signal transmission than wireless transmission.

[0042] Working principle: Reference Figure 1As shown, the 32-bit high-speed processor inside the probe of the measurement module generates a constant high-precision square wave signal and obtains a sine wave signal after frequency division by a differential analog synchronous modulator and filtering by a low-pass filter. This sine wave signal is sent to the detection unit, which is a specially wound differential inductor (i.e., the detection probe). The sine wave signal is used as an excitation signal for displacement detection. When the detection probe is displaced, the position of the internal armature 1 is simultaneously driven to change, and the output voltage of the secondary winding also changes accordingly. The output signal is passed through a differential differential analog synchronous modulator, an amplifier circuit, and a detection circuit to output a DC signal linearly related to the position of the armature 1. After amplification and filtering, it is sent to the built-in ADC of the 32-bit high-speed processor to convert it into a maximum 12-bit high-precision digital signal. Then, the internal 32-bit high-speed microprocessor converts the 12-bit high-precision digital signal into displacement. Finally, the processed data is transmitted to the host through the RS485 communication circuit and further processed by the 32-bit high-speed microprocessor inside the host. At the same time, the processed data is transmitted to the multi-color LED display screen for display, so that users have a stronger humanized visual perception.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-precision LVDT contact displacement sensor, comprising a main control module, a human-machine module and a measurement module, wherein the human-machine module and the measurement module are electrically connected to the main control module respectively, characterized in that: The measurement module includes an inductance unit and a signal processing unit electrically connected to the output end of the inductance unit; the inductance unit uses a mutually coupled inductance coil and an armature as generating elements of electromagnetic induction to detect a complete displacement signal; the signal processing unit receives the electromagnetic induction signal and performs modulation processing, filtering processing, and amplification and detection processing on the received signal.

2. The high-precision LVDT contact displacement sensor according to claim 1, characterized in that: The signal processing unit includes a detection power supply circuit, and a 32-bit high-speed microprocessor, an amplification detection circuit, a filtering circuit, a differential analog synchronous modulator, a frequency division circuit, and a low-pass filtering circuit, which are respectively electrically connected to the detection power supply circuit. The 32-bit high-speed microprocessor is respectively electrically connected to the amplification detection circuit and the differential analog synchronous modulator, the differential analog synchronous modulator is respectively electrically connected to the frequency division circuit, the filtering circuit and the inductance unit, the low-pass filtering circuit is respectively electrically connected to the inductance unit and the frequency division circuit, and the filtering circuit is electrically connected to the amplification detection circuit.

3. The high-precision LVDT contact displacement sensor according to claim 2, characterized in that: The inductor unit comprises an armature (1), a primary winding (2), and a secondary winding (3) coupled to the primary winding; the primary winding (2) is energized to trigger an excitation signal for displacement detection; the secondary winding (3) receives the excitation signal and generates electromagnetic induction with the armature (1); the primary winding (2) and the secondary winding (3) are electrically connected to the low-pass filter circuit and the differential analog synchronous modulator, respectively.

4. The high-precision LVDT contact displacement sensor according to claim 3, characterized in that: The inductance unit also includes a contact head (4), and one end of the armature (1) is fixedly connected to the contact head (4).

5. The high-precision LVDT contact displacement sensor according to claim 1, characterized in that: The main control module includes a main control power supply unit, and a 32-bit high-speed microprocessor, a communication unit and a transmission control unit respectively electrically connected to the main control power supply unit; the communication unit and the transmission control unit are respectively electrically connected to the 32-bit high-speed microprocessor, and the human-machine module is electrically connected to the main control power supply unit.

6. The high-precision LVDT contact displacement sensor according to claim 5, characterized in that: The communication unit is an RS485 communication circuit.

7. The high-precision LVDT contact displacement sensor according to claim 5, characterized in that: The transmission control unit includes an NPN / PNP input / output control circuit and a surge voltage absorption circuit electrically connected to the NPN / PNP input / output control circuit. The surge voltage absorption circuit is electrically connected to the main control power supply unit. The NPN / PNP input / output control circuit is electrically connected to a 32-bit high-speed microprocessor.

8. The high-precision LVDT contact displacement sensor according to claim 5, characterized in that: The human-machine module includes an 8-bit microprocessor, a storage unit, an operation unit, and a display unit, which are respectively electrically connected to the main control power supply unit; the storage unit, the operation unit, and the display unit are respectively electrically connected to the 8-bit microprocessor, and the 8-bit microprocessor is electrically connected to the 32-bit high-speed microprocessor.

9. The high-precision LVDT contact displacement sensor according to claim 2, 5, 7 or 8, characterized in that: The 32-bit high-speed microprocessor is STM32F401CEU6 or STM32F401RET6.

10. The high-precision LVDT contact displacement sensor according to claim 8, characterized in that: The 8-bit microprocessor is PIC16F722.

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