Juing-Huei Su

Further results on the robust stability of linear systems with a single time delay

Abstract For linear systems with a single time-varying delay time, we propose a method to characterize how large the deviation of the delay time can be compared to the nominal zero value, such that the system still preserves its asymptotic stability. Both cases of linear time-delay systems with and without uncertainties are considered. The criteria developed are seen to give less conservative results in simulation examples.

Learning feedback controller design of switching converters via MATLAB/SIMULINK

The application of MATLAB/SIMULINK is developed for simulation and learning feedback controller design of DC-DC switching converters. With the help of its intuitive graphical user interface and some basic circuit theories, the corresponding SIMULINK models of the switching converter circuits can be easily constructed. Students can then use these models to learn and evaluate the closed-loop behavior of the entire system in the MATLAB/SIMULINK environment, after feedback controllers are devised by any classical or modern control theory. The accuracy of this approach is also verified by comparing the simulation results with the responses obtained from a buck-type DC-DC switching converter circuit and existing experimental results.

Stability analysis of linear systems with time delay

This paper presents asymptotic stability criteria for linear systems with time delay. The results not only improve previous results, but also provide a bound for the delay time such that if the system is asymptotically stable when the delay does not exist, it retains the asymptotic stability when the delay time is within the bound. >

A Project-Based Laboratory for Learning Embedded System Design With Industry Support

A project-based laboratory for learning embedded system design with support from industry is presented in this paper. The aim of this laboratory is to motivate students to learn the building blocks of embedded systems and practical control algorithms by constructing a line-following robot using the quadratic interpolation technique to predict the line position. For those students who have acquired basic microcontroller hardware and software programming skills from previous courses, the hands-on exercises in the laboratory include several specific hardware circuits and software algorithms for the final project of constructing the line-following robot. The students are allowed to discuss the hardware and software problems with each other while solving each exercise, although they have to answer the teachers questions individually to earn the score. To enhance the learning outcomes, a racing contest for the students line-following robots is also organized to see how well the techniques learned in the laboratory are applied in the final project. The support from the local branch of Microchip Inc. allows students to obtain C-compilers and microcontrollers at no cost. The feedback from students shows that the final project of constructing line-following robots and the racing contest motivates the students to learn actively all the skills included in the laboratory for embedded system design.

The asymptotic stability of linear autonomous systems with commensurate time delays

The asymptotic stability of linear systems with commensurate time delays is studied. Algorithms are given to check if a given system is asymptotically stable independent of delay or to determine the largest delay time the system can tolerate to preserve its asymptotic stability. These algorithms are simple to apply since they require only to find the eigenvalues of two specially constructed matrices and some simple mathematical calculations. >

Robust stability analysis for uncertain delay systems with output feedback controller

A systematic approach is given in this paper for analyzing the robust stability of uncertain time-delay systems controlled by output feedback. By checking the eigenvalues of a Hamiltonian matrix, the stability of nominal systems can be examined first. Then, for the nominally stable uncertain systems with multiple time delays, a new method using structured singular value technique is proposed for finding a set of uncertain parameters within which the systems remain stable. Moreover, an illustrative example is given to show the usefulness of the proposed approach.

Robust stability analysis of linear continuous/discrete-time systems with output feedback controllers

The robust stability of linear systems with output feedback controllers and time-varying uncertain parameters is considered. The robust stability bounds for time-varying uncertain parameters are given using the Lyapunov method. When there are no uncertain parameters in the input and/or output matrices, it is shown that the result for continuous-time systems is the same as that presented by K.M. Zhou and P.P. Khargonekar (1987), and the result for discrete-time systems is better than that of S.R. Kolla (1989) for the same example. >

New robust stability bounds of linear discrete-time systems with time-varying uncertainties

This paper presents new uncertain parameter variation bounds for linear discrete-time systems to preserve asymptotic stability. The Lyapunov method is utilized to treat both structured and unstructured uncertainties, and the results are optimized with respect to a parameter in the inequality used. When applied to examples considered by previous authors, our results give less conservative bounds.

Analysis and applications of robust nonsingularity problem using the structured singular value

This note uses the structured singular value technique to solve the robust nonsingularity analysis problem for matrices with unstructured and/or quadratically coupled structured uncertainties. With the ready /spl mu/-analysis tools, a new approach is proposed for finding a set of uncertainties within which the perturbed matrix keeps nonsingularity. Applications and examples in robust control theory are given to show the usefulness and the practicality of the proposed approach. >

Integrated current sensing circuit suitable for step-down dc-dc converters

A new integrated current sensing circuit suitable for step-down dc-dc converter is presented in this paper. The current sensing circuit can fully measure the inductor current through sensing the current of power switches whether the high side or low side switch is turned on. The proposed circuits can work in dc-dc converters such that the loading current can be managed through control theories.