CN-116027290-B - Non-contact type vital signal monitoring millimeter wave radar system with mechanical rotation

Abstract

The invention discloses a non-contact type vital signal monitoring millimeter wave radar system with mechanical rotation, and belongs to the technical field of electronic information. The system comprises a computer, a millimeter wave radar, an antenna module, a two-phase four-wire stepping motor, a control chip, a transformer and a driver, and is based on the FMCW and millimeter wave radar technology at the same time. The system is provided with the mechanical rotating device, can realize the omnibearing automatic detection without dead angles on a plane, enlarges the detection area, greatly improves the safety and convenience, can monitor vital signs of different people in real time and conveniently, reduces the waste of manpower resources, and provides an alternative scheme for the vital signal monitoring and the construction of traffic, security inspection and monitoring of special people.

Inventors

• DING XIAO
• LI BOYANG

Assignees

• 电子科技大学

Dates

Publication Date

20260505

Application Date

20221103

Claims (4)

1. 1. The non-contact type vital signal monitoring millimeter wave radar system with the mechanical rotation function is characterized by comprising a computer, a millimeter wave radar, an antenna module, a two-phase four-wire stepping motor, a control chip, a transformer and a driver; The antenna module comprises a transmitting antenna and a receiving antenna, wherein the transmitting antenna continuously transmits frequency modulation continuous pulse signals to the detection area, and the receiving antenna receives echo signals reflected by targets in the detection area and feeds the echo signals back to the millimeter wave radar; The millimeter wave radar is used for driving the antenna module to enter a working state according to a computer driving instruction, receiving echo signals, performing mixing sampling processing on the echo signals to obtain azimuth data and vital sign information of each vital body, and then transmitting the azimuth data and vital sign information of each vital body to a computer; The computer is used for sending a driving instruction to the millimeter wave radar, receiving azimuth data and vital sign information of each living body, processing to obtain position information and respiration and heartbeat information of each living body in the detection area and displaying the result, and sending a parameter transformation instruction to the control chip; the control chip is used for generating an output pulse signal, a direction signal and an enabling signal according to a parameter transformation instruction of the computer and sending three signals to the driver; The driver is used for receiving three paths of signals sent by the control chip, integrating the three paths of signals into two paths of driving signals and transmitting the two paths of driving signals to the two-phase four-wire stepping motor; the two-phase four-wire stepping motor is used for receiving two paths of driving signals provided by the driver and driving the life detection module to scan different rotation modes and rotation parameters; The transformer is used for converting 220V high voltage into working voltage to supply power for the system.
2. 2. The non-contact vital signal monitoring millimeter wave radar system with mechanical rotation of claim 1, wherein the rotation modes of the two-phase four-wire stepper motor comprise three modes, namely a first continuous rotation mode, a second stepping rotation mode, a third scanning rotation mode and a fourth scanning rotation mode, wherein the first continuous rotation mode enables the stepper motor to continuously rotate for 360 degrees and conduct omnibearing scanning on surrounding scenes; the rotation parameters of the two-phase four-wire stepping motor comprise the rotation speed, the rotation direction and the rotation angle of the motor.
3. 3. The non-contact vital signal monitoring millimeter wave radar system with the mechanical rotation function according to claim 2, wherein an ADC module and a DSP module are arranged in the millimeter wave radar, wherein the ADC module is used for carrying out analog-to-digital conversion processing on signals, and the DSP module is used for carrying out fast Fourier transform calculation on digital signals.
4. 4. The non-contact type vital signal monitoring millimeter wave radar system with mechanical rotation as claimed in claim 3, wherein the non-contact type vital signal monitoring method realized by the system is based on FMCW and millimeter wave radar technology, and comprises the following specific realization steps: S1, a millimeter wave radar drives a transmitting antenna to transmit frequency modulation continuous pulse signals to a detection area, and then receives echo signals reflected by a target through a receiving antenna and feeds back the echo signals to the millimeter wave radar; S2, performing mixing sampling processing on echo signals by the millimeter wave radar to obtain intermediate frequency signals IF, wherein the frequency of the intermediate frequency signals IF is equal to the product of the slope of the frequency modulation continuous pulse signals and the time difference between the echo signals and the frequency modulation continuous pulse signals, and obtaining azimuth data of a target according to the frequency of the intermediate frequency signals IF: d=f 0 c/2S Wherein d is the distance between the target and the radar, f 0 is the frequency of the intermediate frequency signal, c is the propagation speed of the electromagnetic wave in the air, and S is the derivative of the frequency modulated continuous pulse signal; S3, an ADC module arranged in the millimeter wave radar performs analog-to-digital conversion processing on the intermediate frequency signal, and transmits the digital signal to a DSP module arranged in the millimeter wave radar; s4, performing Fast Fourier Transform (FFT) on the digital signals by the DSP module to separate vital sign information of the targets at different directions and distances, and transmitting the vital sign information and the direction data of each target to a computer; S5, compared with a frequency modulation continuous pulse signal transmitted by a transmitting antenna, vital sign information of a single target can generate phase deviation delta phi, and the phase deviation delta phi is adopted to represent the displacement delta d of a chest of a living body, and the specific calculation method is as follows: Wherein f c is the initial frequency of the frequency modulated continuous pulse signal; S6, taking Δd as an ordinate and time t as an abscissa to obtain a vital signal image of chest cavity displacement changing along with time, wherein the vital signal image is formed by superposing a respiratory signal, a heartbeat signal and a clutter signal, and in order to reduce calculation complexity, the respiratory signal and the heartbeat signal are regarded as standard sine waves, so that a vital signal expression is obtained: x(t)=A 1 sin(2πf 1 t+Φ 1 )+A 2 sin(2πf 2 t+Φ 2 )+n(t) Wherein, A 1 is the heartbeat signal amplitude, f 1 is the heartbeat signal frequency, phi 1 is the initial phase of the heartbeat signal, A 2 is the respiratory signal amplitude, f 2 is the respiratory signal frequency, phi 2 is the initial phase of the respiratory signal, and n (t) is the clutter signal; S7, filtering the life signal image through a Butterworth filter, filtering clutter, separating a breathing signal and a heartbeat signal to obtain breathing and heartbeat information of each life body, and finally displaying the position information and the breathing and heartbeat information of each life body through a computer.

Description

Non-contact type vital signal monitoring millimeter wave radar system with mechanical rotation Technical Field The invention belongs to the technical field of electronic information, and particularly relates to a millimeter wave radar system provided with a mechanical rotating device and used for non-contact vital signal monitoring. Background In different fields, detection of vital signs has different application values. In medical treatment, vital signs and health states of patients such as respiration and heart rate can be monitored in real time through an electrocardiograph, so that medical staff can diagnose, treat and care the patients conveniently. In military, suspicious personnel can be detected through the life finder, and the method has great significance for national defense safety. The current automatic driving automobile which is raised in the global tide also determines whether people exist around the automobile by means of a radar seeker, so that the safety and reliability of automatic driving are improved. The present life signal detection is mainly divided into contact type and non-contact type detection technologies. The touch life detection mainly uses Electrocardiograph (ECG), uses sensing equipment such as electrode paste to collect bioelectric signals generated during heart activity, uses Digital Signal Processor (DSP) and ARM as processing cores to process the collected bioelectric signals, and finally displays relevant parameters on a screen. The documents ' Xu Xinjian, xu Haishu, zhang Zhifang, shang Dongsheng, mao Kunjian ' STM 32-based wireless vital sign monitoring system design [ J ]. Chinese medical equipment, 2017,14 (09): 11-14 ', propose a wireless vital sign monitoring system, which collects various physiological information of a patient through a sensor acquisition module and transmits the physiological parameter monitoring information of the patient to a central monitoring station through a wireless transmission module. Although such wireless detection systems may be free of wire constraints, increasing the comfort of real-time vital sign monitoring of a patient, they still rely on wearable acquisition modules. In many cases, contact life detection has certain limitations, such as being obviously inadequate for burn patients, skin patients and mental patients. Even for ordinary people contact life detection, long-time real-time monitoring cannot be realized, and a plurality of inconveniences exist, so the value and the meaning of the non-contact life detection are gradually highlighted. Non-contact vital signs detection is mainly performed remotely by light, sound, infrared, radar signals and the like. Literature Zhou Zaoli research on target detection methods based on LFMCW millimeter wave radar [ D ] Nanjing university of post and E.C. 2020 ], a 77GHz Linear Frequency Modulation Continuous Wave (LFMCW) radar target detection system is proposed to realize non-contact vital signal detection. However, the integrated life detection system is often limited by the detection range, detection dead angles exist on the side surface and the back surface of the detection system, the echo signal processing process is relatively complicated, and the detection difficulty is increased. Besides the application scenes such as medical science and safety monitoring, the non-contact life detection system can be used as a front-end sensor oriented to automatic driving and the Internet of things. The literature Zhang Xiaomei discloses a vehicle-mounted laser radar ranging method and an accuracy analysis [ D ]. Electronic technology university, 2019. The laser radar has the characteristics of higher angular resolution and distance resolution and high detection precision. However, the light pulse emitted by the laser radar is difficult to modulate, has poor penetrability and is easily influenced by heavy fog, rain and snow weather. In the literature, a method for detecting the distance and the position of a target by using a laser radar is proposed, but whether the target is a living body or not is not distinguished, which clearly increases the difficulty of background data processing. In addition, if the vehicle is to be monitored in an omnidirectional environment, it is necessary to install more than ten radars around the vehicle body due to the limitation of the detection range of the radar itself, and the cost of the extremely high-cost lidar is certainly reduced, but even for the millimeter waves Lei Dalai which are slightly low in price, the problem of excessively high cost is also caused. Disclosure of Invention The invention provides a non-contact type vital signal monitoring millimeter wave radar system with mechanical rotation, which aims to solve the defects of small detection range, single scanning mode, complex echo signal processing, limitation in special application scenes and the like in the prior art. The technical scheme adopted by the invention is as follows: The non-contact