A sound target-searching robot system which includes a 4-channel microphone array for\nsound collection, magneto-resistive sensor for declination measurement, and a wireless sensor\nnetworks (WSN) for exchanging information is described. It has an embedded sound signal\nenhancement, recognition and location method, and a sound searching strategy based on a digital\nsignal processor (DSP). As the wireless network nodes, three robots comprise the WSN a personal\ncomputer (PC) in order to search the three different sound targets in task-oriented collaboration.\nThe improved spectral subtraction method is used for noise reduction. As the feature of audio signal,\nMel-frequency cepstral coefficient (MFCC) is extracted. Based on the K-nearest neighbor classification\nmethod, we match the trained feature template to recognize sound signal type. This paper utilizes\nthe improved generalized cross correlation method to estimate time delay of arrival (TDOA), and\nthen employs spherical-interpolation for sound location according to the TDOA and the geometrical\nposition of the microphone array. A new mapping has been proposed to direct the motor to search\nsound targets flexibly. As the sink node, the PC receives and displays the result processed in the\nWSN, and it also has the ultimate power to make decision on the received results in order to improve\ntheir accuracy. The experiment results show that the designed three-robot system implements sound\ntarget searching function without collisions and performs well.
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