Cyber-Physical Systems

Compositional Design of Cyber-Physical Systems Using Port-Hamiltonian Systems 43

Engine

e

s

f

s

I

0

e

1

e

sw2

sw2

f

sw2

e

sw1

f

sw1

e

1

C

e

2

C

C

sw1

C

1

1

f

1

e

2

f

2

FIGURE 2.7 Generalized bond graph model of the starter motor.

The inertia from the engine has the following constituent equation:

d

dt

e

j

=

f

j

J

, (2.5)

where J is the moment of inertia value.

Hybrid dynamics is central to the operation of the starter motor. Hybrid dynamics are implemented

as switch networks. Given that one of the constituent variables of a switch is always equal to zero, a

switch will never contribute any power to the system. A generalized bond graph model of the starter

motor is presented in Figure 2.7.