基于有阻尼自由振动的超声波测距系统的设计
发布时间：2019-06-04 14:26
【摘要】：在非接触式测距系统中,超声波测距在汽车防撞、海底定位、物位检测、机器人导航、无人作战平台和医疗探伤等民用、军事及工业生产领域应用十分广泛。本文设计了一种基于有阻尼自由振动的超声波测距系统,能够准确测量渡越时间,提高了测距的精确度和稳定性。传统的基于有阻尼自由振动的超声波测距系统是通过测量超声波传播的渡越时间实现超声波测距的,然而超声波信号接收完毕后,超声波接收振子存在有阻尼自由振动现象,振子依然振动使计时器计时延长,渡越时间增加,从而对测距的精确度产生影响。通过对超声波产生、传播、接收过程进行动力学分析,针对影响渡越时间测量准确性的振子有阻尼自由振动进行分析和研究,提出了一种通过周期频率来判别振子做受迫振动还是阻尼振动的方法,使得系统在超声波信号接收完毕后能够准确得出渡越时间,消除振子有阻尼振动现象造成的不利影响。基于有阻尼自由振动的超声波测距系统设计包括硬件设计和软件设计两个方面。在硬件设计上,发射端设计了正弦波发生电路、功率放大电路和超声波信号发射电路。接收端设计了接收放大电路、时间增益补偿电路、有源带通滤波电路、温度测量电路,通过STM32控制芯片,配合完成超声波信号的发送和接收信号的采集。软件设计方面,提出一种有阻尼自由振动的超声波测距系统频率拐点的判别方法。具体为将A/D采样后数据由DSP数据处理器进行逐个点的FFT变换,得到每个点的幅度谱和相位谱。根据幅度谱中某一点和其相邻点的幅度值所对应的频率的差别,可以明确地得出超声波信号相邻两个点的频率变化,从而准确地判别出有阻尼自由振动的超声波测距系统的频率拐点。通过该拐点能够精确地测量渡越时间,提高测距精度。多次实验表明,本超声波测距系统的绝对误差限制在0.30mm范围内,与传统同类技术相比精确度和稳定性都有很大提升。
[Abstract]:In contactless ranging system, ultrasonic ranging is widely used in civil, military and industrial fields, such as automobile collision prevention, seafloor positioning, object level detection, robot navigation, unmanned combat platform and medical flaw detection. In this paper, an ultrasonic ranging system based on damped free vibration is designed, which can accurately measure the transit time and improve the accuracy and stability of ranging. The traditional ultrasonic ranging system based on damped free vibration realizes ultrasonic ranging by measuring the transit time of ultrasonic propagation. However, after the ultrasonic signal is received, the ultrasonic receiving oscillator has the phenomenon of damped free vibration. The vibration of the oscillator still prolongs the timer timing and increases the transit time, which affects the accuracy of ranging. Through the dynamic analysis of the ultrasonic generation, propagation and reception process, the damped free vibration of the oscillator, which affects the accuracy of the transit time measurement, is analyzed and studied. In this paper, a method is proposed to distinguish whether the oscillator is forced vibration or damped vibration by periodic frequency, so that the system can accurately obtain the transit time after the ultrasonic signal is received, and eliminate the adverse effects caused by the damped vibration of the oscillator. The design of ultrasonic ranging system based on damped free vibration includes hardware design and software design. In the hardware design, the sine wave generating circuit, the power amplifier circuit and the ultrasonic signal transmitting circuit are designed at the transmitter. The receiver designs a receiving amplifier circuit, a time gain compensation circuit, an active bandpass filter circuit, a temperature measurement circuit, and a STM32 control chip to complete the transmission of ultrasonic signals and the acquisition of received signals. In the aspect of software design, a method for judging the frequency inflection point of ultrasonic ranging system with damped free vibration is proposed. The amplitude spectrum and phase spectrum of each point are obtained by FFT transformation of A 鈮，
本文编号：2492782
[Abstract]:In contactless ranging system, ultrasonic ranging is widely used in civil, military and industrial fields, such as automobile collision prevention, seafloor positioning, object level detection, robot navigation, unmanned combat platform and medical flaw detection. In this paper, an ultrasonic ranging system based on damped free vibration is designed, which can accurately measure the transit time and improve the accuracy and stability of ranging. The traditional ultrasonic ranging system based on damped free vibration realizes ultrasonic ranging by measuring the transit time of ultrasonic propagation. However, after the ultrasonic signal is received, the ultrasonic receiving oscillator has the phenomenon of damped free vibration. The vibration of the oscillator still prolongs the timer timing and increases the transit time, which affects the accuracy of ranging. Through the dynamic analysis of the ultrasonic generation, propagation and reception process, the damped free vibration of the oscillator, which affects the accuracy of the transit time measurement, is analyzed and studied. In this paper, a method is proposed to distinguish whether the oscillator is forced vibration or damped vibration by periodic frequency, so that the system can accurately obtain the transit time after the ultrasonic signal is received, and eliminate the adverse effects caused by the damped vibration of the oscillator. The design of ultrasonic ranging system based on damped free vibration includes hardware design and software design. In the hardware design, the sine wave generating circuit, the power amplifier circuit and the ultrasonic signal transmitting circuit are designed at the transmitter. The receiver designs a receiving amplifier circuit, a time gain compensation circuit, an active bandpass filter circuit, a temperature measurement circuit, and a STM32 control chip to complete the transmission of ultrasonic signals and the acquisition of received signals. In the aspect of software design, a method for judging the frequency inflection point of ultrasonic ranging system with damped free vibration is proposed. The amplitude spectrum and phase spectrum of each point are obtained by FFT transformation of A 鈮，
本文编号：2492782
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