University of Mississippi eGrove Honors College (Sally McDonnell Barksdale Honors Theses Honors College) 2016 Ultrasonic Doppler Sonar Sensor System for Extraction of Walk Signatures Demba B. Komma University of Mississippi. Sally McDonnell Barksdale Honors College Follow this and additional works at: https://egrove.olemiss.edu/hon_thesis Part of the Electrical and Computer Engineering Commons Recommended Citation Komma, Demba B., "Ultrasonic Doppler Sonar Sensor System for Extraction of Walk Signatures" (2016). Honors Theses. 264. https://egrove.olemiss.edu/hon_thesis/264 This Undergraduate Thesis is brought to you for free and open access by the Honors College (Sally McDonnell Barksdale Honors College) at eGrove. It has been accepted for inclusion in Honors Theses by an authorized administrator of eGrove. For more information, please contact [email protected]. ULTRASONIC DOPPLER SONAR SENSOR SYSTEM FOR EXTRACTION OF WALK SIGNATURES by Demba Bakary Komma A thesis submitted to the faculty of The University of Mississippi in partial fulfillment of the requirements of the Sally McDonnell Barksdale Honors College. Oxford, MS December 2016 Approved by Advisor: Dr. Matthew Morrison Reader: Dr. James M. Sabatier Reader: Dr. Joseph R. Gladden c 2016 Demba Bakary Komma ALL RIGHTS RESERVED ii Acknowledgments I will like to thank my thesis advisor Dr. Matthew Morrison for his guidance in compiling my research work, and the writing of this thesis. Dr. Morrison taught me on the fundamentals on writing a good thesis, and prepared me well for my defense. I am grateful to Dr. James Sabatier for being a mentor to me for the past three years, and for serving on my thesis committee. Dr. Sabatier taught me the research process, and helped explain the mathematical and physical concepts of using ultrasonic sensors to extract Doppler features. The experiments done in my research would not have been possible without his support, and that of his company SOAIR LLC. I used the SOAIR LLC labs for most of the experiments that I did for my research. I will like to thank my professors for their guidance and knowledge that they gave me which helped in completing this research project. I am thankful to Dr. Gladden for being one of my readers, and serving on my defense committee. Finally I am eternally grateful to my family for the sacrifices they took to make sure I had a good education. iii Abstract In this work, a portable low cost sensor system is designed for the extraction of walking signatures in humans using the principle of Ultrasonic Doppler Sonar (UDS). UDS involves the use of two ultrasonic transducers acting as a transmitter- receiver pair. The transmitter produces a continuous ultrasonic signal at a specific frequency to be broadcasted onto a moving target, while the receiver will perform a frequency shift on the reflected signal in relation to the movement of the target. The sensor system used in this work is comprised of a frequency generator that drives the transducer with a 40 kHz sine wave and a data acquisition device. Signal processing methods were implemented on the received data to extract and analyze the Doppler features of a human walk. Data was initially collected using a function generator which produced the trans- mitted 40 kHz signal together with Measurement Computing WaveBook-516E data acquisition measurement hardware. To make the system portable, the design was sim- plified using the National Instruments USB-6216 Data Acquisition (DAQ) for both the transmitted signal and saving the received sampled data. The WaveView data ac- quisition software was used to control the WaveBook DAQ while a LabView program was written to interface with the NI USB-6216 hardware. The primary objective of implementing the sensor system is to automate the data collection without the use of a computer, which the use of NI data acquisition made possible, but the system parts were expensive and needed the use of a laptop to manage the process. A microprocessor, together with an Analog to Digital Converter (ADC) and a Digital to Analog Converter (DAC), were tested for generating the driving transmit- iv ting signal and the collection of the data. The TI C6748 digital signal processors on the Texas Instruments OMAP-L138 Development Kit was the chosen processor as it is a floating-/fixed-point DSP with up to 456 MHz clock speed, the access to standard interfaces on the development kit, and the availability of software development kits, drivers, and algorithm libraries for fast development. v Contents Acknowledgments iii Abstract iv Abbreviations x 1 Literature Survey 1 2 Operation of Ultrasonic Doppler System 4 2.1 Principle of Operation of the UDS . 4 2.2 IQ Demodulation . 5 2.3 Spectrograms . 6 3 Components of the UDS Sensor System 8 3.1 Ultrasonic Transducers . 8 3.2 Signal Generator . 9 3.3 Pre-Amplifier . 10 3.4 Data Acquisition System . 11 4 Demodulation Methods 13 4.1 Experimental Setup . 13 4.2 Data Analysis . 14 4.3 Results . 16 5 Validation of UDS Sensor System 18 5.1 Experimental Setup . 18 vi 5.2 Data Analysis . 18 5.3 Results . 19 6 Automatic UDS Sensor System 24 6.1 Hardware Components . 24 6.1.1 Passive Infrared Sensor . 24 6.1.2 MATSUN/PAN EFR-RC40K transducers . 25 6.1.3 Analog Modules Model 351A-3 Amplifier . 25 6.1.4 MINMAX ABF-04D15 AC/DC Power Module . 25 6.1.5 NI USB-6216 DAQ Device . 26 6.2 LabVIEW Software Program . 26 6.3 System Test . 28 7 Experimental Tests On Gait Features 29 7.1 Doppler Features of a Normal Walk . 29 7.2 Effects of Location of Sensors . 31 7.3 Effects of Feet Noise . 34 7.4 Effects of Swinging Arms . 37 7.5 Multipath Doppler Effect . 41 8 Using Microprocessors to Make a Data Acquisition System 45 8.1 Test for Signal Generation . 46 8.2 Test for Sampling signals . 47 9 Conclusion and Future Work 49 10 Appendix 51 10.1 Appendix A . 51 10.2 Appendix B . 55 vii List of Figures 3.1 Ultrasonic transducers collocated in a plastic box . 9 4.1 Spectrogram Obatined from Direct Demodulation . 15 4.2 Spectrogram Obatined from IQ Demodulation . 15 5.1 Pendulum at 1 m away and 10 cm displacement-UDS Sensor . 20 5.2 Pendulum at 1 m away and 10 cm displacement-Radar Sensor . 21 5.3 Pendulum at 2 m away and 40 cm displacement-UDS Sensor . 21 5.4 Pendulum at 2 m away and 40 cm displacement-Radar Sensor . 22 5.5 Pendulum at 4 m away and 10 cm displacement-UDS Sensor . 22 5.6 Pendulum at 4 m away and 10 cm displacement-Radar Sensor . 23 6.1 Graphical Representation of UDS sensor system . 27 6.2 Spectrogram of pendulum swing . 28 7.1 Subject walking away from transducer . 30 7.2 Subject walking towards transducer . 31 7.3 Sensors at feet level . 32 7.4 Sensors at knee level . 33 7.5 Sensors at waist level . 33 7.6 Leg Swing with ground contact . 35 7.7 Subject walking with shoes . 36 7.8 Subject walking with socks . 36 7.9 Arm swing three footsteps away . 38 7.10 Arm swing six footsteps away . 39 viii 7.11 Arm swing nine footsteps away . 39 7.12 Subject walking with both hands inside . 40 7.13 Subject walking with one hand inside . 40 7.14 Pendulum swing in lab without foam . 42 7.15 Pendulum swing in lab with foam . 43 7.16 Stationary Pendulum . 43 7.17 Pendulum swing in Anechoid Chamber without foam . 44 7.18 Pendulum swing in Anechoid Chamber with foam . 44 8.1 TI OMAP-L138 Development Kit(LCDK) with XDS200 JTAG . 46 8.2 1 kHz sine wave generated from TI C6748 and TLC5616 DAC . 47 8.3 1000 samples of 1 kHz sine wave sampled with TL4541 ADC . 48 ix Abbreviations AC Alternating current ADC Analog to Digital Converter BNC Bayonet NeillConcelman CCS Code Composer Studio CSV Comma separated values DAC Digital to Analog Converter DAQ Data Acquisition System DC Direct current DSP Digital Signal Processor FFT Fast Fourier Transform FM Frequency Modulated I(t) In-phase signal IDE Integrated Development Environment JTAG Joint Test Action Group kS/s kilo samples per second NI National Instruments PIR Passive Infrared Q(t) Quadrature signal RTOS Real Time Operating System x SD Secure Digital card SDK Software Development Kit SPI Serial Peripheral Interface SRS Stanford Research Systems STFT Short Time Fourier Transform TI Texas Instruments UDS Ultrasonic Doppler Sonar xi 1. Literature Survey Ultrasonic Doppler Sonar (UDS) sensors have been used in a variety of appli- cations such as in range finding [1], collision detection [2], object recognition [3], and human motion detection [4]. A continuous wave radar system for human gait recog- nition was done through the use of low cost microwave sensors and the use of an oscillator to transmit a stable continuous wave signal on to a moving object [5]. The received signal from the object corresponds with the Doppler frequency of the moving target. The reflected signal is then mixed with the transmitted signal to remove the carrier, converting into baseband which is digitalized using a data acquisition module sand saved onto a laptop. This method was applied to a person walking towards and away from the sensor system as the moving target. The reflected signal from a per- son walking will be mainly from the legs, torso and the arm with a constant Doppler shift for a person walking at a constant velocity. A short-time Fast Fourier Trans- form (SFFT) was used to form spectrograms to extract the velocity component of the human motions which were used for gait recognition and differentiation of human motion from animal motion.