scholarly journals Adaptive Control for Nonlinear Systems with Time-Varying Control Gain

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Alejandro Rincon ◽  
Fabiola Angulo
Keyword(s):  
Adaptive Control ◽  
Dead Zone ◽  
Permanent Magnet Synchronous Motor ◽  
Adaptive Robust Control ◽  
Type Model ◽  
Time Varying ◽  
Plant Model ◽  
Control Gain ◽  
Control Scheme ◽  
Nonlinear Plants

We propose a scheme for nonlinear plants with time-varying control gain and time-varying plant coefficients, on the basis of a plant model consisting of a Brunovsky-type model with polynomials as approximators. We develop an adaptive robust control scheme for this plant, under the following assumptions: (i) the plant terms involve time-varying but bounded coefficients, being its upper bound unknown; (ii) the control gain is unknown, not necessarily bounded, and only its signum is known. To achieve robustness, we use a combination of robustifying control inputs and dead zone-type update laws. We apply this methodology to the speed control of a permanent magnet synchronous motor (PMSM), and we achieve proper tracking results.

scholarly journals Adaptive Finite-Time Mixed Interlayer Synchronization of Two-Layer Complex Networks with Time-Varying Coupling Delay

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Xiaoyun Tang ◽  
Zhanying Yang ◽  
Jie Zhang
Keyword(s):  
Adaptive Control ◽  
Complex Networks ◽  
Finite Time ◽  
Sufficient Conditions ◽  
Lyapunov Stability Theory ◽  
Time Varying ◽  
Coupling Delay ◽  
Noise Perturbation ◽  
Control Scheme ◽  
Adaptive Control Strategy

This paper is concerned with two-layer complex networks with unidirectional interlayer couplings, where the drive and response layer have time-varying coupling delay and different topological structures. An adaptive control scheme is proposed to investigate finite-time mixed interlayer synchronization (FMIS) of two-layer networks. Based on the Lyapunov stability theory, a criterion for realizing FMIS is derived. In addition, several sufficient conditions for realizing mixed interlayer synchronization are given. Finally, some numerical simulations are presented to verify the correctness and effectiveness of theoretical results. Meanwhile, the proposed adaptive control strategy is demonstrated to be nonfragile with the noise perturbation.

Bilateral Adaptive Control of Nonlinear Teleoperation Systems With Uncertain Dynamics and Dead-Zone

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Xia Liu ◽  
Mahdi Tavakoli
Keyword(s):  
Adaptive Control ◽  
Function Analysis ◽  
Dead Zone ◽  
Adaptive Controller ◽  
Bilateral Control ◽  
Uncertain Dynamics ◽  
Teleoperation System ◽  
Control Scheme ◽  
Teleoperation Systems ◽  
Dynamic Uncertainties

Dead-zone is one of the most common hard nonlinearities ubiquitous in master–slave teleoperation systems, particularly in the slave robot joints. However, adaptive control techniques applied in teleoperation systems usually deal with dynamic uncertainty but ignore the presence of dead-zone. Dead-zone has the potential to remarkably deteriorate the transparency of a teleoperation system in the sense of position and force tracking performance or even destabilizing the system if not compensated for in the control scheme. In this paper, an adaptive bilateral control scheme is proposed for nonlinear teleoperation systems in the presence of both uncertain dynamics and dead-zone. An adaptive controller is designed for the master robot with dynamic uncertainties and the other is developed for the slave robot with both dynamic uncertainties and unknown dead-zone. The two controllers are incorporated into the four-channel bilateral teleoperation control framework to achieve transparency. The transparency and stability of the closed-loop teleoperation system is studied via a Lyapunov function analysis. Comparisons with the conventional adaptive control which merely deal with dynamic uncertainties in the simulations demonstrate the validity of the proposed approach.

Aeroelastic Suppression of Wind Turbine Blade Using Trailing-Edge Flap

2013 ◽  
Author(s):  
Nailu Li ◽  
Mark J. Balas
Keyword(s):  
Adaptive Control ◽  
Wind Turbine ◽  
Stability Theorem ◽  
Time Varying ◽  
Aeroelastic System ◽  
Aerodynamic Loads ◽  
Proposed Model ◽  
Control Scheme ◽  
Trailing Edge Flap ◽  
Adaptive Control Scheme

The variation of aeroelastic system dynamics is treated as the change of time-varying aerodynamic loads along the operation trajectory of a spinning wind turbine. An Adaptive Control scheme is introduced to suppress flutter based on the proposed model. The robustness and effectiveness of Adaptive Control is shown by simulation results. For stability analysis, Adaptive Stability Theorem is proved theoretically by Kalman-Yacubovic Lemma and demonstrated numerically by certain cases.

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