Showing papers by "Hassan K. Khalil published in 2001"
TL;DR: Closed-loop analysis shows that the sampled-data controller recovers the performance of the continuous time controller as the sampling frequency and observer gain become sufficiently large.
Abstract: This paper studies sampled-data control of nonlinear systems using high-gain observers. The observer is designed in continuous time, then discretized using three different discretization methods. Closed-loop analysis shows that the sampled-data controller recovers the performance of the continuous time controller as the sampling frequency and observer gain become sufficiently large. The theory is illustrated by experimental results.
180 citations
TL;DR: It is shown that by implementing the control law using a high-gain observer, it can recover the performance of the state feedback controller.
Abstract: We extend the separation results of a previous work of ours (1999) to a case where a globally bounded state feedback controller renders a certain compact set positively invariant and asymptotically attractive. The extension covers a wide range of control tasks that arise in adaptive control, servomechanisms, and practical stabilization. It is shown that by implementing the control law using a high-gain observer, we can recover the performance of the state feedback controller.
108 citations
04 Dec 2001
TL;DR: In this paper, a robust integral controller for single-input single-output (SISO) nonlinear systems with well defined normal form and exponentially stable zero dynamics is presented. But the design of robust integral control for SISO systems is not addressed in this paper.
Abstract: Deals with the design of robust integral control for single-input single-output (SISO) nonlinear systems with well defined normal form and exponentially stable zero dynamics. We develop further the universal controller design that was initiated in the work of Khalil (2000). The modification to the controller of Khalil is done in two steps. First, the integrator equation is modified to include not only the tracking error, but a linear combination of the tracking error and its derivatives, up to a certain order. Next, an additional input, in the spirit of classical anti-reset windup is added to the integrator to prevent it from winding up. Analytical results are given for both regional as well as,semiglobal regulation. The performance of the proposed controller is illustrated through simulations.
17 citations
TL;DR: In this paper, a trajectory following problem for a class of smooth bounded time-varying vector reference signals is considered and an output feedback integral controller is designed to ensure ultimately bounded tracking error which could be made as small as required.
3 citations