Abstract-A two dimensional (2-D) direction of arrival (DOA) estimation method for L-shaped array with automatic pairing is proposed. It exploits the conjugate symmetry property of the array manifold matrix to increase the effective array aperture and the number of virtual snapshots simultaneously, and then applies the principle of MUSIC to construct an angle cost function and transforms the conventional 2-D search into 1-D via a Rayleigh quotient, which can greatly reduce the computation complexity. Finally, the azimuth and elevation angles are estimated without pair matching. Simulation results show that the proposed method has a better performance and can resolve more sources than some existing computationally efficient methods.
In this paper, the saturated practical stabilization problem is addressed for a class of nonholonomic mobile robots based on visual servoing feedback with uncertain camera parameters. The new switching control design method to be proposed is directly based on the original system, which can avoid the problem of singularity arising from state or input transformation. A saturated discontinuous controller is presented by applying the multi-step switching control strategy and the theory of finite-time stability. The closed-loop system can be stabilized to a prescribed arbitrarily small neighborhood of the zero equilibrium point in a finite time. Finally, the simulation results show the effectiveness of the proposed controller design approach.
A novel two-dimensional (2-D) direct-of-arrival (DOA) and mutual coupling coefficients estimation algorithm for uniform rectangular arrays (URAs) is proposed. A general mutual coupling model is first built based on banded symmetric Toeplitz matrices, and then it is proved that the steering vector of a URA in the presence of mutual coupling has a similar form to that of a uniform linear array (ULA). The 2-D DOA estimation problem can be solved using the rank-reduction method. With the obtained DOA information, we can further estimate the mutual coupling coefficients. A better performance is achieved by our proposed algorithm than those auxiliary sensor-based ones, as verified by simulation results.
In this paper, the finite-time tracking control problem is discussed for extended nonholonomic chained-form systems with parametric uncertainty, unmodeled nonlinear dynamics and external uncertain time-varying disturbances. Two decoupled subsystems are considered, for which an anti-interference controller is proposed by combining finite-time stability control theory and chattering-free sliding-mode design strategy in the presence of the uncertainty, nonlinearity and perturbation. Moreover, for the corresponding closed-loop systems under the given control law, rigorous finite-time stability analysis is presented at the origin equilibrium point. Finally, the main conclusions are applied to the trajectory tracking control of dynamic nonholonomic mobile robots with visual servoing feedback, and the simulation results show the effectiveness of our control design approach.
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