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Embedded Software Modeling and Design
Published in Louis Scheffer, Luciano Lavagno, Grant Martin, EDA for IC System Design, Verification, and Testing, 2018
The hybrid automata model [22] combines discrete transition graphs with continuous dynamical systems. The value of system variables may change according to a discrete transition or it may change continuously in system states according to a trajectory defined by a system of differential equations. Hybrid automata have been developed for the purpose of modeling digital systems interacting with (physical) analog environments, but the capability of stopping the evolution of clock variables in states (first derivative equal to 0) makes the formalism suitable for the modeling of systems with preemption.
Multi-Robot Cooperation
Published in Shuzhi Sam Ge, Frank L. Lewis, Autonomous Mobile Robots, 2018
Rafael Fierro, Luiz Chaimowicz, Vijay Kumar
A hybrid automaton is a finite automaton augmented with a finite number of real-valued variables that change continuously, as specified by differential equations and inequalities, or discretely, according to specific assignments. It is used to describe hybrid systems, that is, systems that are composed by discrete and continuous states. A hybrid automaton H can be defined as: H = {Q, V, E, f, Inv, G, Init, R}. Q = {1,2,…, S} is the set of discrete states, also called control modes. The set V represents the variables of the system and can be composed by discrete (Vd) and continuous (Vc) variables: V = Vd ∪ Vc. Each variable v ∈ V has a value that is given by a function v(v). This is called valuation of the variables. Thus, the state of the system is given by a pair (q, v), composed by the discrete state q ∈ Q and the valuation of the variables. The dynamics of the continuous variables are determined by the flows f, generally described as differential equations inside each control mode (fq). Discrete transitions between pairs of control modes (p, q) are specified by the control switches E (also called edges). Invariants (Inv) and guards (G) are predicates related to the control modes and control switches respectively. The system can stay in a certain control mode while its invariant is satisfied, and can take a control switch when its guard (jump condition) is satisfied. The initial states of the system are given by Init, and each control switch can also have a reset statement R associated, to change the value of some variable during a discrete transition.
H
Published in Phillip A. Laplante, Dictionary of Computer Science, Engineering, and Technology, 2017
hybrid specification models a specification technique for modeling linear continuous properties of a system. Hybrid automata are extensions of finite state automata to continuous quantities. They allow continuous properties of the operating environment to be specified and modeled directly. Finite state automata provide a mathematical foundation for reasoning about systems in terms of their discrete properties. In hybrid automata, state transitions may be triggered by functions on continuous variables.
Automated generation of hybrid automata for multi-rigid-body mechanical systems and its application to the falsification of safety properties
Published in Mathematical and Computer Modelling of Dynamical Systems, 2018
E.M. Navarro-López, M.D. O’Toole
The results presented in this paper must be distinguished from the different simulators for hybrid and cyber-physical systems like Stateflow of Simulink® [54], Modelica [55], Ptolemy [47] or CyPhySim [56]. However, since the MRB hybrid automaton fits within the standard automaton framework, it should be possible to implement the derived hybrid automaton on other hybrid system simulators. A by-product of the automated MRB hybrid automaton generation has been the automated creation of Simulink S-functions. These S-functions implement the hybrid automaton and can be dropped into the Simulink models to interact with other components. Given this, a similar approach could be followed for other simulator tools.