Wireless Sensor Networks Based Sound Source Target Search Multi-Robot System

Sound source search robot is composed of microphone array sensors, magneto resistive sensor, wireless sensor networks node and mobile robot vehicle. Using microphone array sensors for voice acquisition and magneto resistive sensor for course measurement, robot can accomplish sound source recognition, source localization and source search, and ultimately find sound source target. The robot system combines wireless sensor networks, microprocessor technology, signal processing and computer technology together, and will have a broad application prospects at voice control of robot and person search and rescue in dangerous situations.The system consists of three mobile robots, which as network nodes and PC (Sink node) compose the wireless sensor network. PC fuses the sound source recognition results of the three robots, can realizes that the three robots working together and searching each sound target in environment with noise. In the process of sound search, robot saves the key message as text file in the SD card memory, PC displays the course, angle of sound and so on information of each robot, and also accomplishes control of the robots.In this paper, theory of algorithms, hardware and software in three areas of robot system are studied, and the effectiveness of the design program is verified through experiments.Theory of algorithms adopt Mel-frequency Cepstral coefficients, generalized cross correlation and spherical interpolation positioning method, which are used to achieve sound source recognition, time delay of estimation and source localization respectively. In addition, the sound search method leads robot to complete the task of sound source search.Hardware platform is based on DSP TMS320F28335, and function modules contain external extended RAM, motor control and drive, signal conditioning of microphone array and the magneto resistive sensors, real-time clock, SD card memory, wireless sensor networks node, serial communication.Software platform is composed of three parts programs: DSP data processing and control, PC display and control and wireless sensor networks (WSN) node transceiver. Program of DSP data processing and control, which is the core of the system, can accomplish the operation of algorithms and control of robot; Program of PC receives and displays the course, sound source direction angle, results of sound source recognition and so on information which is sent by robots, fuses sound source recognition results of the three robots, and achieves the control of the three robots; Program of WSN node transceiver fulfills wireless communication between the robots and Sink node, and also achieves measurement of the distance between nodes (robots).Finally, experiments of sound source search system are performed. When the three songs containing noise are played asynchronously through three speakers respectively, the three robots can find their own sound sources eventually, and achieves the desired result and validates the effectiveness of this system.