Modeling and Simulation of Hybrid Systems - 12

Question 1

What are the key components of an hybrid automata?

Answer 1

invariant, guard, jump and flow functions

Question 2

How do we convert to a Hybrid statechart?

Answer 2

Guard sets: modeled as conditions of discrete transitions.
Flow function: specified after the keyword throughout
Jump function: specified after the keyword exit within a state or
attached to a discrete transition.
Invariant: Most work does not specify invariants for statecharts.
Instead, urgent semantics are assumed, i.e., a transition is taken as
soon as a state is in a guard set

Question 3

What is the concept of deadlock in hybrid automata?

Answer 3

A deadlock occurs when the
continuous state leaves the invariant
and is not in any guard set.

Question 4

What is the concept of livelock in hybrid automata?

Answer 4

A livelock occurs when the system switches infinitely often between
discrete states and no time passes in between discrete transitions.

Question 5

What is Zeno behavior?

Answer 5

Zeno behavior occurs when the duration δi between the i th and the (i + 1)th transition decreases and sum^∞_i=0 δi is finite. With other words, an
infinite number of transitions occurs in finite time.

Question 6

What is finite escape time?

Answer 6

One speaks of finite escape time, when ||x|| → ∞ in finite time. Finite
escape time is also possible for purely continuous systems when they are
nonlinear

Question 7

How to detect guard detection?

Answer 7

When the guard set is crossed the levvel set function I(x) changs its sign.