CN214410266U

CN214410266U - Multifunctional high-precision position and angle sensor real-time digital demodulation system

Info

Publication number: CN214410266U
Application number: CN202120578611.XU
Authority: CN
Inventors: 都高峰; 罗腾利; 史宝祥; 王旭锴; 刘伟
Original assignee: Xian Lingkong Electronic Technology Co Ltd
Current assignee: Xian Lingkong Electronic Technology Co Ltd
Priority date: 2021-03-22
Filing date: 2021-03-22
Publication date: 2021-10-15
Anticipated expiration: 2031-03-22

Abstract

The utility model provides a real-time digital demodulation system of multi-functional high accuracy position and angle sensor, belongs to position/angle measurement system's technical field, its characterized in that: the device comprises an excitation circuit, a monitoring circuit, a conditioning circuit, a BIT circuit and an FPGA module; the conditioning circuit comprises a differential amplification module, a low-pass filtering module and a program control amplification module which are electrically connected in sequence; the program control amplification module is electrically connected with the analog-digital converter. The amplification and signal quality improvement of the input signal of the sensor are realized through a conditioning circuit; providing a stimulus source through a stimulus circuit; the position and angle sensors are monitored on line in real time in an operating state through a monitoring circuit; the self-checking under the power-on state and other states is realized through the BIT circuit so as to improve the testability of the system; real-time digital demodulation system of multi-functional high accuracy position and angle sensor strong in instantaneity, measurement accuracy is high, can effectively restrain the temperature drift, eliminate zero point error.

Description

Multifunctional high-precision position and angle sensor real-time digital demodulation system

Technical Field

The utility model belongs to the technical field of position/angle measurement system, especially, relate to a real-time digital demodulation system of multi-functional high accuracy position and angle sensor.

Background

Linear Variable Differential Transformer (LVDT)/Rotary Variable Differential Transformer (RVDT) as position and angle sensors have many advantages of frictionless measurement, infinite mechanical life, infinite resolution, robustness, strong environmental adaptability, etc., and are widely applied to flight control systems, the output signal of the sensor is an analog signal, and the traditional analog demodulation open loop control has poor conversion accuracy, low linearity and single function.

Disclosure of Invention

The utility model aims at solving the above problem, provide a multi-functional high accuracy position and the real-time digital demodulation system of angle sensor that real-time nature is strong, measurement accuracy is high.

The utility model discloses a real-time digital demodulation system of multi-functional high accuracy position and angle sensor, including excitation circuit, monitoring circuit, conditioning circuit, BIT circuit and FPGA module; the excitation circuit and the BIT circuit are electrically connected with the FPGA module; an analog-digital converter is arranged between the monitoring circuit and the FPGA module; the monitoring circuit and the conditioning circuit are electrically connected with the analog-digital converter; the analog-digital converter is electrically connected with the FPGA module; the conditioning circuit comprises a differential amplification module, a low-pass filtering module and a program control amplification module which are electrically connected in sequence; the program control amplification module is electrically connected with the analog-digital converter. Signals output by the position and angle sensors are subjected to differential amplification, so that common-mode interference is effectively reduced; and then high-frequency interference signals are filtered by a low-pass filter circuit, and signals reaching the analog-digital converter are enabled to always reach the input full-scale range by a program control amplifier in order to ensure that the measuring circuit obtains higher resolution at the zero nonlinear part and facilitate later error control.

Furthermore, the utility model discloses a multi-functional high accuracy position and angle sensor real-time digital demodulation system, excitation circuit includes DDS module and the drive amplifier circuit that electricity is connected in proper order; the DDS module is electrically connected with the FPGA; the monitoring circuit comprises a summing module and a proportional amplification module which are electrically connected in sequence; the proportional amplification module is electrically connected with the analog-digital converter; the BIT circuit comprises a standard source and an analog switch which are electrically connected in sequence.

Further, the real-time digital demodulation system of multi-functional high accuracy position and angle sensor, the input signal scope of monitoring circuit and conditioning circuit is +12V to-12V.

Further, the utility model discloses a multi-functional high accuracy position and angle sensor real-time digital demodulation system, the low pass filter module is provided with 4 th order low pass filter; the cut-off frequency of the low-pass filter is 50kHz, and the low-pass filter is used for improving the signal quality and facilitating the acquisition of a post-stage circuit.

Further, multi-functional high accuracy position and angle sensor real-time digital demodulation system, the programmable logic device of XILINX is adopted to the FPGA module for functions such as configuration, on-line monitoring, BIT's of algorithm demodulation, excitation source detect.

The utility model discloses a real-time digital demodulation system of multi-functional high accuracy position and angle sensor realizes the amplification and the signal quality promotion of sensor input signal through the conditioning circuit; providing a stimulus source through a stimulus circuit; the position and angle sensors are monitored on line in real time in an operating state through a monitoring circuit; the self-checking under the power-on state and other states is realized through the BIT circuit so as to improve the testability of the system; real-time digital demodulation system of multi-functional high accuracy position and angle sensor strong in instantaneity, measurement accuracy is high, can effectively restrain the temperature drift, eliminate zero point error.

Drawings

FIG. 1 is a schematic structural view of a real-time digital demodulation system for a multi-functional high-precision position and angle sensor according to the present invention;

fig. 2 is a schematic circuit diagram of a low-pass filter module according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a BIT circuit according to the embodiment of the present invention.

Detailed Description

The multi-functional high-precision position and angle sensor real-time digital demodulation system of the present invention is described in detail with reference to the accompanying drawings and embodiments.

The real-time digital demodulation system of the multifunctional high-precision position and angle sensor in the embodiment of the disclosure comprises an excitation circuit, a monitoring circuit, a conditioning circuit, a BIT circuit and an FPGA module as shown in FIG. 1; the excitation circuit and the BIT circuit are electrically connected with the FPGA module; an analog-digital converter is arranged between the monitoring circuit and the FPGA module; the monitoring circuit and the conditioning circuit are electrically connected with the analog-digital converter; the analog-digital converter is electrically connected with the FPGA module; the conditioning circuit comprises a differential amplification module, a low-pass filtering module and a program control amplification module which are electrically connected in sequence; the program control amplification module is electrically connected with the analog-digital converter; the FPGA module is electrically connected with an upper computer through an RS422 interface.

The excitation circuit of the embodiment of the present disclosure includes a DDS module and a driving amplifier circuit electrically connected in sequence; the DDS module is electrically connected with the FPGA; the monitoring circuit comprises a summing module and a proportional amplification module which are electrically connected in sequence; the proportional amplification module is electrically connected with the analog-digital converter; the BIT circuit comprises a standard source and an analog switch which are electrically connected in sequence. The position and angle sensors in the disclosed embodiments are LVDTs/RVDTs; the input signal range of the monitoring circuit and the conditioning circuit is +12V to-12V; as shown in fig. 2, the low-pass filtering module is provided with a 4-order low-pass filter; the cut-off frequency of the low-pass filter is 50kHz, so that the signal quality is improved, and the acquisition of a post-stage circuit is facilitated; the FPGA module adopts a XILINX programmable logic device and is used for the functions of algorithm demodulation, excitation source configuration, online monitoring, BIT detection and the like; the BIT circuit structure of this embodiment is shown in fig. 3.

In the embodiment of the disclosure, the conditioning circuit is composed of a differential amplification module, a low-pass filtering module and a program control amplification module; the differential amplification module is used for amplifying and sampling the output signals of the LVDT/RVDT and is used for filtering the common-mode interference of the output signals of the LVDT/RVDT and improving the signal quality; the low-pass filtering module is used for filtering input signals and filtering high-frequency interference of output signals of the LVDT/RVDT, and a 4-order low-pass filter with the cut-off frequency of 50kHz is arranged in the embodiment of the disclosure and used for improving the signal quality and facilitating the acquisition of a later circuit. The program control amplification module is used for obtaining higher resolution at the zero nonlinear part, and when the FPGA detects that the amplitude of an input signal is lower, the amplification factor of the input signal is improved through the program control amplification circuit, so that the resolution of the system at the zero nonlinear part is improved, and later-stage error control is facilitated.

The analog-to-digital converter ADC is used to complete the acquisition from the analog circuit to the digital circuit. The excitation circuit is used for generating an excitation source of the LVDT/RVDT, a direct digital synthesizer DDS circuit is adopted, and signals such as the amplitude, the frequency and the like of the excitation source are changed in real time in a program according to the sampling amplitude, so that the high-precision demodulation requirement of the sensor is met. The monitoring circuit is used for monitoring the health state of the LVDT/RVDT sensor in real time on line, and the on-line real-time monitoring of the system on the key sensor LVDT/RVDT in the running state is improved. The BIT circuit is used for self-checking in power-on and other states and is used for improving the testability of the system. The FPGA module is used for the functions of algorithm demodulation, excitation source configuration, online monitoring, BIT detection and the like. And the RS422 is used for communication of board card data to finish demodulation signals and signal return of the health state of the sensor.

The signal output by the LVDT/RVDT sensor is differentially amplified,common mode interference is effectively reduced; and high-frequency interference signals are filtered by the low-pass filter circuit, so that the measuring circuit obtains higher resolution at the zero nonlinear part, the later error control is facilitated, and the signals reaching the analog-digital converter can always reach the input full range by the program control amplifier. In the specific implementation process, the relation between the sampling frequency and the improved conversion bit number is f through an oversampling technology_os=4ⁿ*f_sWherein f is_osFor oversampling frequency, f_sThe lowest frequency required for initial sampling; the sampling frequency was set to 500kHz and the number of conversion bits increased was about 2 bits. And after the signals are converted by the ADC, the signals are converted into digital signals, and then the digital signals are processed by adopting a Goertzel algorithm. And sampling for several periods, taking the average value as RVDT/LVDT output, and performing error compensation to serve as the calculated output amplitude. The amplitude of the excitation signal can be changed by controlling the DDS in real time through the FPGA, so that the amplitude of the back-sampling signal is changed, a closed loop is formed, and the sampling precision can be effectively improved.

Claims

1. The utility model provides a real-time digital demodulation system of multi-functional high accuracy position and angle sensor which characterized in that: the device comprises an excitation circuit, a monitoring circuit, a conditioning circuit, a BIT circuit and an FPGA module; the excitation circuit and the BIT circuit are electrically connected with the FPGA module; an analog-digital converter is arranged between the monitoring circuit and the FPGA module; the monitoring circuit and the conditioning circuit are electrically connected with the analog-digital converter; the analog-digital converter is electrically connected with the FPGA module; the conditioning circuit comprises a differential amplification module, a low-pass filtering module and a program control amplification module which are electrically connected in sequence; the program control amplification module is electrically connected with the analog-digital converter.

2. The multi-functional high precision position and angle sensor real-time digital demodulation system of claim 1, wherein: the excitation circuit comprises a DDS module and a driving amplification circuit which are electrically connected in sequence; the DDS module is electrically connected with the FPGA; the monitoring circuit comprises a summing module and a proportional amplification module which are electrically connected in sequence; the proportional amplification module is electrically connected with the analog-digital converter; the BIT circuit comprises a standard source and an analog switch which are electrically connected in sequence.

3. The multi-functional high precision position and angle sensor real-time digital demodulation system of claim 2, wherein: the input signal range of the monitoring circuit and the conditioning circuit is +12V to-12V.

4. The multi-functional high precision position and angle sensor real-time digital demodulation system of claim 3, wherein: the low-pass filtering module is provided with a 4-order low-pass filter; the cut-off frequency of the low-pass filter is 50 kHz.

5. The multi-functional high precision position and angle sensor real-time digital demodulation system of claim 4, wherein: the FPGA module adopts a XILINX programmable logic device.