MIT Department of Electrical Engineering & Computer Science

E E C S

Modeling, Analysis, and Control of Hybrid Systems

Dr. Michael S. Branicky
Massachusetts Institute of Technology

Tuesday, April 16, 1996
2:00 PM (1:45 refreshments)
Grier Room B, 34-401B
EECS Special Seminar

Abstract

Complex natural and engineered systems typically possess a hierarchical structure, characterized by continuous-variable dynamics at the lowest level and logical decision-making at the highest. Virtually all control systems today---from flight control to the factory floor---perform computer-coded checks and issue logical as well as continuous-variable control commands. The interaction of these different types of dynamics and information leads to a chato a challenging set of "hybrid" analysis and control problems.

We first identify the phenomena that arise in such real-world systems. Then, we introduce a mathematical model of "hybrid systems" as interacting collections of dynamical systems, evolving on continuous-variable state spaces, and subject to continuous controls and discrete transitions.

We develop tools for analyzing hybrid systems, encompassing limit cycle existence, perturbation robustness, and stability. These tools represent a departure from previous ad hoc methods like extensive simulation. As a demonstration, we prove global asymptotic stability for a typical aircraft controller that logically switches between two conventional controllers.

We develop tools for synthesizing hybrid controllers for hybrid plants in an optimal control framework. In particular, we demonstrate existence of optimal (chattering) and near optimal (non-chattering) controls and derive "generalized quasi-variational inequalities" that the associated value function satisfies. We outline algorithms for solving these inequalities based on a generalized Bellman equation, impulse control, and linear programming. Several illustrative examples are solved.


URL of this page: http://www-eecs.mit.edu/AY95-96/events/41.html
Created: Apr 1, 1996  | Modified: Jun 25, 1997
This announcement is from the MIT EECS 1995-96 archive.  | Current events
To MIT EECS home page  | Your comments and inquiries are welcome.