Acoustic formation control for nonholonomic mobile robots

Two leader-follower formation controllers are proposed for a group of nonholonomic mobile robots. Each controller is installed on the following robot and requires local sensory stimuli to move the follower into its formation's desired position. As a result, communication between robots is not necessary to maintain a desired formation. The first proposed controller utilizes range and bearing data from an acoustic sensor to move the follower into position. It assumes an acoustic source is attached to the leader and a stationary landmark. The second proposed controller is a landmark-less formation controller that assume two sources are attached to the leader, and the follower is equipped with an acoustic array and inertial sensor. Results show each controller exponentially reduces the tracking error to a steady-state level and can maintain stability, even in regions where the formation kinematics becomes singular.;For two-dimensional passive arrays, a general method is described that ranks and selects multiple microphone configurations within the array that are likely to produce accurate position estimates. This method segments a two-dimensional array into various combinations and configurations of microphone pairs and flattens these configurations into one-dimension for comparison. Each configuration is ranked based on the microphones' spatial information (known a-priori) and incoming bearing estimates. These rankings select different microphone pair configurations, whose position estimates are combined in an adaptive weighted-average algorithm. Simulations and experimental results show that this method selects microphone configurations that provide the least position error. Through a fusion algorithm, which combines individual microphone pair data, an array's position accuracy can improve.