| Robots are generally composed of electromechanical parts with multiple sensors and actuators. The overall behavior of a robot emerges from coordination among its various parts and interaction with its environment. Developing intelligent, reliable, robust and safe robots, or real-time embedded systems, has become a focus of interest in recent years. In this thesis, we establish a foundation for modeling, specifying and verifying discrete/continuous hybrid systems and take an integrated approach to the design and analysis of robotic systems and behaviors.;A robotic system in general is a hybrid dynamic system, consisting of continuous, discrete and event-driven components. We develop a semantic model for dynamic systems, that we call Constraint Nets (CN). CN introduces an abstraction and a unitary framework to model discrete/continuous hybrid systems. CN provides aggregation operators to model a complex system hierarchically. CN supports multiple levels of abstraction, based on abstract algebra and topology, to model and analyze a system at different levels of detail. CN, because of its rigorous foundation, can be used to define programming semantics of real-time languages for control systems.;While modeling focuses on the underlying structure of a system--the organization and coordination of its components--requirements specification imposes global constraints on a system's behavior, and behavior verification ensures the correctness of the behavior with respect to its requirements specification. We develop a timed linear temporal logic and timed ;A good design methodology can simplify the verification of a robotic system. We develop a systematic approach to control synthesis from requirements specification, by exploring a relation between constraint satisfaction and dynamic systems using constraint methods. With this approach, control synthesis and behavior verification are coupled through requirements specification.;To model, synthesize, simulate, and understand various robotic systems we have studied in this research, we develop a visual programming and simulation environment that we call ALERT: A Laboratory for Embedded Real-Time systems. |
