
Compositional Design of Cyber-Physical Systems Using Port-Hamiltonian Systems 53
Engine storage function vs. time
Time
Energy (J)
1.2E5
1.0E5
8.0E4
6.0E4
4.0E4
2.0E4
0.0E0
0.0 0.4 0.8 1.2 1.6 2.0 2.4 2.8
FIGURE 2.12 Storage function of the engine.
The nonlinearity inside the torque map manifests itself in the nonlinear Dirac structure in Equation
2.32. A graphical port-Hamiltonian description of the engine component is shown in Figure 2.11. The
control port (e
r
, f
r
) allows the engine system to interface with control software; the control software
takes f
r
as input from the engine and provides e
r
as output to the engine. Combining the inputs and
outputs of the ...