Results 11  20
of
135
Automotive engine control and hybrid systems: challenges and opportunities
 Proceedings of the IEEE
, 2000
"... The design of engine control systems has been traditionally carried out using a mix of heuristic techniques validated by simulation and prototyping using approximate averagevalue models. However, the ever increasing demands on passengers ’ comfort, safety, emissions, and fuel consumption imposed by ..."
Abstract

Cited by 57 (15 self)
 Add to MetaCart
The design of engine control systems has been traditionally carried out using a mix of heuristic techniques validated by simulation and prototyping using approximate averagevalue models. However, the ever increasing demands on passengers ’ comfort, safety, emissions, and fuel consumption imposed by car manufacturers and regulations call for more robust techniques and the use of cycleaccurate models. We argue that these models must be hybrid because of the combination of timedomain and eventbased behaviors. In this paper, we present a hybrid model of the engine in which both continuous and discrete timedomain as well as eventbased phenomena are modeled in a separate but integrated manner. Based on this model, we formalize the specification of the overall engine control by defining a number of hybrid control problems. To cope with the difficulties arising in the design of hybrid controllers, a design methodology is proposed. This methodology consists of a relaxation
KeYmaera: A hybrid theorem prover for hybrid systems
 IJCAR. VOLUME 5195 OF LNCS
, 2008
"... KeYmaera is a hybrid verification tool for hybrid systems that combines deductive, real algebraic, and computer algebraic prover technologies. It is an automated and interactive theorem prover for a natural specification and verification logic for hybrid systems. KeYmaera supports differential dyn ..."
Abstract

Cited by 55 (23 self)
 Add to MetaCart
(Show Context)
KeYmaera is a hybrid verification tool for hybrid systems that combines deductive, real algebraic, and computer algebraic prover technologies. It is an automated and interactive theorem prover for a natural specification and verification logic for hybrid systems. KeYmaera supports differential dynamic logic, which is a realvalued firstorder dynamic logic for hybrid programs, a program notation for hybrid automata. For automating the verification process, KeYmaera implements a generalized freevariable sequent calculus and automatic proof strategies that decompose the hybrid system specification symbolically. To overcome the complexity of real arithmetic, we integrate real quantifier elimination following an iterative background closure strategy. Our tool is particularly suitable for verifying parametric hybrid systems and has been used successfully for verifying collision avoidance in case studies from train control and air traffic management.
Impulse differential inclusions: A viability approach to hybrid systems
 IEEE Transactions on Automatic Control
, 2002
"... Abstract. Impulse differential inclusions are introduced as a framework for modelling hybrid phenomena. Connections to standard problems in area of hybrid systems are discussed. Conditions are derived that allow one to determine whether a set of states is viable or invariant under the action of an i ..."
Abstract

Cited by 47 (7 self)
 Add to MetaCart
(Show Context)
Abstract. Impulse differential inclusions are introduced as a framework for modelling hybrid phenomena. Connections to standard problems in area of hybrid systems are discussed. Conditions are derived that allow one to determine whether a set of states is viable or invariant under the action of an impulse differential inclusion. For sets that violate these conditions, methods are developed for approximating their viability and invariance kernels, that is the largest subset that is viable or invariant under the action of the impulse differential inclusion. The results are demonstrated on examples. 1.
DifferentialAlgebraic Dynamic Logic for DifferentialAlgebraic Programs
"... Abstract. We generalise dynamic logic to a logic for differentialalgebraic programs, i.e., discrete programs augmented with firstorder differentialalgebraic formulas as continuous evolution constraints in addition to firstorder discrete jump formulas. These programs characterise interacting discr ..."
Abstract

Cited by 41 (27 self)
 Add to MetaCart
Abstract. We generalise dynamic logic to a logic for differentialalgebraic programs, i.e., discrete programs augmented with firstorder differentialalgebraic formulas as continuous evolution constraints in addition to firstorder discrete jump formulas. These programs characterise interacting discrete and continuous dynamics of hybrid systems elegantly and uniformly. For our logic, we introduce a calculus over real arithmetic with discrete induction and a new differential induction with which differentialalgebraic programs can be verified by exploiting their differential constraints algebraically without having to solve them. We develop the theory of differential induction and differential refinement and analyse their deductive power. As a case study, we present parametric tangential roundabout maneuvers in air traffic control and prove collision avoidance in our calculus.
The Hierarchical Lattices of a Finite Machine
 Systems and Control Letters
, 1995
"... The concept of dynamical consistency is introduced to define a high level transition function for an arbitrary partition of the state space of a finite inputstate machine M. The existence of a dynamically consistent transition from a partition member X i to a member X j corresponds to the existenc ..."
Abstract

Cited by 26 (10 self)
 Add to MetaCart
(Show Context)
The concept of dynamical consistency is introduced to define a high level transition function for an arbitrary partition of the state space of a finite inputstate machine M. The existence of a dynamically consistent transition from a partition member X i to a member X j corresponds to the existence, for every state x in X i , of some (x dependent) control sequence which takes that state directly into X j . This paper analyses what are termed inblock controllable partition machines and betweenblock controllable partition machines, and establishes the existence of the associated inblock controllable hierarchical lattice IBCP (M). It is shown that any partition machine in IBCP (M) is betweenblock controllable if and only if the base machine M is controllable. This setting allows the specification of state to state control trajectories of M to be decomposed into high level and low level components. Keywords: discrete event systems, controllability, system decomposition, hierarchical ...
Robust Controller Synthesis for Hybrid Systems Using Modal Logic
 Hybrid Systems: Computation and Control (HSCC’01), volume 2034 of LNCS
, 2001
"... . In this paper, we formulate and robustly solve a quite general class of hybrid controller synthesis problems. The type of controller we investigate is the switching control mechanism of a hybrid automaton (via guard and mode invariant sets), and the robustness result is with respect to variations ..."
Abstract

Cited by 23 (3 self)
 Add to MetaCart
(Show Context)
. In this paper, we formulate and robustly solve a quite general class of hybrid controller synthesis problems. The type of controller we investigate is the switching control mechanism of a hybrid automaton (via guard and mode invariant sets), and the robustness result is with respect to variations in the right hand sides of the dierential equations that depend continuously on a parameter. We present a novel methodology for controller design and synthesis which uses modal logic as a formalism for reasoning about sets of plant states, and various operators on sets arising from the dierential equations and from metric tolerance relations on the state space. 1 Introduction In general terms, a hybrid system H can be said to satisfy a performance speci cation robustly if every system H 0 in some nominated variation class around H also satis es that speci cation. Likewise, a synthesis procedure for a class of control problems can be called robust if the nominal closedloop hyb...
Lecture notes on hybrid systems
, 2004
"... The aim of this course is to introduce some fundamental concepts from the area of hybrid systems, that is dynamical systems that involve the interaction of continuous (real valued) states and discrete (finite valued) states. Applications where these types of dynamics play a prominent role will be hi ..."
Abstract

Cited by 22 (0 self)
 Add to MetaCart
(Show Context)
The aim of this course is to introduce some fundamental concepts from the area of hybrid systems, that is dynamical systems that involve the interaction of continuous (real valued) states and discrete (finite valued) states. Applications where these types of dynamics play a prominent role will be highlighted. We will introduce general methods for investigating properties such as existence of solutions, reachability and decidability of hybrid systems. The methods will be demonstrated on the motivating applications. Students who successfully complete the course should be able to appreciate the diversity of phenomena that arise in hybrid systems and how discrete “discrete ” entities and concepts such as automata, decidability and bisimulation can coexist with continuous entities and
European Train Control System: A Case Study in Formal Verification
, 2009
"... Complex physical systems have several degrees of freedom. They only work correctly when their control parameters obey corresponding constraints. Based on the informal specification of the European Train Control System (ETCS), we design a controller for its cooperation protocol. For its free paramet ..."
Abstract

Cited by 22 (10 self)
 Add to MetaCart
(Show Context)
Complex physical systems have several degrees of freedom. They only work correctly when their control parameters obey corresponding constraints. Based on the informal specification of the European Train Control System (ETCS), we design a controller for its cooperation protocol. For its free parameters, we successively identify constraints that are required to ensure collision freedom. We formally prove the parameter constraints to be sharp by characterizing them equivalently in terms of reachability properties of the hybrid system dynamics. Using our deductive verification tool KeYmaera, we formally verify controllability, safety, liveness, and reactivity properties of the ETCS protocol that entail collision freedom. We prove that the ETCS protocol remains correct even in the presence of perturbation by disturbances in the dynamics. We verify that safety is preserved when a PI controlled speed supervision is used.
Nonlinear and Hybrid Control Via RRTs
 In Proc. Intl. Symp. on Mathematical Theory of Networks and Systems
, 2002
"... In this paper, we review rapidlyexploring random trees (RRTs) for motion planning, experiment with them on standard control problems, and extend them to the case of hybrid systems. ..."
Abstract

Cited by 20 (2 self)
 Add to MetaCart
(Show Context)
In this paper, we review rapidlyexploring random trees (RRTs) for motion planning, experiment with them on standard control problems, and extend them to the case of hybrid systems.