1,185 research outputs found
Co-design of output feedback laws and event-triggering conditions for linear systems
We present a procedure to simultaneously design the output feedback law and
the event-triggering condition to stabilize linear systems. The closed-loop
system is shown to satisfy a global asymptotic stability property and the
existence of a strictly positive minimum amount of time between two
transmissions is guaranteed. The event-triggered controller is obtained by
solving linear matrix inequalities (LMIs). We then exploit the flexibility of
the method to maximize the guaranteed minimum amount of time between two
transmissions. Finally, we provide a (heuristic) method to reduce the amount of
transmissions, which is supported by numerical simulations
Nonlinear control of feedforward systems with bounded signals
Published versio
Design of Dynamic Output Feedback Laws Based on Sums of Squares of Polynomials
We consider the stabilization of nonlinear polynomial systems and the design of dynamic output feedback laws based on the sums of squares (SOSs) decompositions. To design the dynamic output feedback laws, we show the design conditions in terms of the state-dependent linear matrix inequalities (SDLMIs). Because the feasible solutions of the SDLMIs are found by the SOS decomposition, we can obtain the dynamic output feedback laws by using numerical solvers. We show numerical examples of the design of dynamic output feedback laws
Fuzzy control turns 50: 10 years later
In 2015, we celebrate the 50th anniversary of Fuzzy Sets, ten years after the main milestones regarding its applications in fuzzy control in their 40th birthday were reviewed in FSS, see [1]. Ten years is at the same time a long period and short time thinking to the inner dynamics of research. This paper, presented for these 50 years of Fuzzy Sets is taking into account both thoughts. A first part presents a quick recap of the history of fuzzy control: from model-free design, based on human reasoning to quasi-LPV (Linear Parameter Varying) model-based control design via some milestones, and key applications. The second part shows where we arrived and what the improvements are since the milestone of the first 40 years. A last part is devoted to discussion and possible future research topics.Guerra, T.; Sala, A.; Tanaka, K. (2015). Fuzzy control turns 50: 10 years later. Fuzzy Sets and Systems. 281:162-182. doi:10.1016/j.fss.2015.05.005S16218228
Exponential and Prescribed-Time Extremum Seeking with Unbiased Convergence
We present multivariable extremum seeking (ES) designs that achieve unbiased
convergence to the optimum. Two designs are introduced: one with exponential
unbiased convergence (unbiased extremum seeker, uES) and the other with
user-assignable prescribed-time unbiased convergence (unbiased PT extremum
seeker, uPT-ES). In contrast to the conventional ES, which uses persistent
sinusoids and results in steady-state oscillations around the optimum, the
exponential uES employs an exponentially decaying amplitude in the perturbation
signal (for achieving convergence) and an exponentially growing demodulation
signal (for making the convergence unbiased). The achievement of unbiased
convergence also entails employing an adaptation gain that is sufficiently
large in relation to the decay rate of the perturbation amplitude. Stated
concisely, the bias is eliminated by having the learning process outpace the
waning of the perturbation. The other algorithm, uPT-ES, employs
prescribed-time convergent/blow-up functions in place of constant amplitudes of
sinusoids, and it also replaces constant-frequency sinusoids with chirp signals
whose frequency grows over time. Among the convergence results in the ES
literature, uPT-ES may be the strongest yet in terms of the convergence rate
(prescribed-time) and accuracy (unbiased). To enhance the robustness of uES to
a time-varying optimum, exponential functions are modified to keep oscillations
at steady state. Stability analysis of the designs is based on a state
transformation, averaging, local exponential/PT stability of the averaged
system, local stability of the transformed system, and local exponential/PT
stability of the original system. For numerical implementation of the developed
ES schemes and comparison with previous ES designs, the problem of source
seeking by a two-dimensional velocity-actuated point mass is considered.Comment: 16 pages, 7 figure
- …