7,979 research outputs found
Nonlinear Adaptive Control Using Gaussian Networks with Composite Adaptation for Improved Convergence
The use of composite adaptive laws for control of the affine class of nonlinear systems having unknown dynamics is proposed. These dynamics are approximated by Gaussian radial basis function neural network whose parameters are updated by a composite law that is driven by both tracking and estimation errors, combining techniques used in direct and indirect adaptive control. This is motivated by the need to improve the speed of convergence of the unknown parameters, hence resulting in a better system performance. The inherent approximation error of the neural networks might lead to instability because of parameter drift. This is compensated for by augmenting the control law with a low gain sliding mode component and using deadzone adaptation for the indirect part of the composite law, The stability of the system is analysed and the effectiveness of the method is demonstrated by simulation and comparison with a direct adaptive control scheme
Adaptive Predictive Control Using Neural Network for a Class of Pure-feedback Systems in Discrete-time
10.1109/TNN.2008.2000446IEEE Transactions on Neural Networks1991599-1614ITNN
Output feedback NN control for two classes of discrete-time systems with unknown control directions in a unified approach
10.1109/TNN.2008.2003290IEEE Transactions on Neural Networks19111873-1886ITNN
Composite Learning Control With Application to Inverted Pendulums
Composite adaptive control (CAC) that integrates direct and indirect adaptive
control techniques can achieve smaller tracking errors and faster parameter
convergence compared with direct and indirect adaptive control techniques.
However, the condition of persistent excitation (PE) still has to be satisfied
to guarantee parameter convergence in CAC. This paper proposes a novel model
reference composite learning control (MRCLC) strategy for a class of affine
nonlinear systems with parametric uncertainties to guarantee parameter
convergence without the PE condition. In the composite learning, an integral
during a moving-time window is utilized to construct a prediction error, a
linear filter is applied to alleviate the derivation of plant states, and both
the tracking error and the prediction error are applied to update parametric
estimates. It is proven that the closed-loop system achieves global
exponential-like stability under interval excitation rather than PE of
regression functions. The effectiveness of the proposed MRCLC has been verified
by the application to an inverted pendulum control problem.Comment: 5 pages, 6 figures, conference submissio
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