1. Structured Modeling of Mechatronic Systems in which you meet the modest but talented multiport component

2. Characterization of Modern Engineering Systems
Features of modern engineering systems:
multiple physical domains
energy transfer processes (thermodynamic networks, first-law principle)
energy conversion processes (transducers)
information transfer (signals)
increasingly larger and more complex

3. Engineering modeling is an art, not a science.
Models should be “designed” to answer certain questions of the product development team.
Under-modeling may cause the team to miss certain critical behaviors.
Over-modeling may obscure insight into causes of behavior.
Over-modeling leads to excessive costs during optimization and sensitivity testing.

5. Basic Concepts in Multiport Modeling
A multiport component interacts through a set of ports.
Two port types - power ports for energy, signal ports for information interaction.
Connectors join same port types in pairs.
Models can be organized hierarchically (e.g., to control density of information display).
Models can be organized for re-use (libraries).

6. Some multiport components
Permanent-magnet motor: a 2-port
electrical port, shaft port
Positive-displacement pump: a 3-port
shaft, high-P fluid, low-P fluid ports
Hydraulic cylinder: a 3-port
ram port, fluid port A, fluid port B
Op-amp integrating circuit: a 2-port
electrical input, output ports
Solenoid valve: a 2-port
slider port, electrical port

7. Permanent-magnet motoria +
τ, ω
> ea
Electrical port
Rotational port ea τ
PMMOTOR ia ω

8. Hydraulic cylinder Q1 Q2 VL FL P1 P2 A1 A2
HCYLINDER FL VL
P1 Q1
P2 Q2

11. Common power port types
mechanical translation: force, velocity
mechanical rotation: torque, angular velocity
electrical terminal-pair: voltage, current
fluid power: pressure, volume flow
magnetic power: mmf, flux rate
thermal power: temperature, entropy rate
Note that power is the product of the port variable pair.

12. Units for common power port types
translation: force [N], velocity [m/s]
rotation: torque [Nm], angular velocity [rad/s]
electrical: voltage [v], current [A]
fluid power: pressure [N/m2], volume flow [m3/s]
Note that power is the product of the port variable pair. In the units given above, the power is Watts for all port types.

13. Some common power connectors
translation: rod {force, velocity}
rotation: shaft {torque, angular velocity}
electrical: wire pair {voltage, current}
fluid power: pipe, hose {pressure, volume flow}
An ideal connector has no material properties of importance (e.g., inertia, compliance, resistance, friction, etc.) It conveys the energy instantly from one port to the other port without losses or delays.

14. Multiport modeling is useful because ...
it applies to mechatronics systems. (both power and signal types; transducers)
it is effective at both simple and complex levels. (easy to learn; extendible)
it is graphical in nature. (good visualization properties; hierarchical)
it lends itself to computer implementation. (good user interface; object-oriented)

15. Multiport modeling is compatible with existing modeling methods.
Mechanics: Newton’s laws, free-body diagrams.
Mechanics: Lagrange’s method - energy
Electrical circuits: Kirchoff’s laws
Electronic components: representation as ported devices (i.e., circuit elements)
Transducers: consistent modeling approach based on power/energy across domains

16. Multiport modeling is compatible with existing modeling methods. (cont
It can represent more abstract modeling forms.
Finite-element representation (M,C,K matrices)
Modal representation of vibratory systems (normal modes)
Power-conserving transformations
(e.g., xyz to spherical coordinate mapping)
Transfer functions and impedance methods

17. Multiport modeling can help your career
You can demonstrate awareness of the “big picture” and the details of a project.
You can demonstrate control over the level of model complexity suitable for the project.
You can organize models for re-use.
You can communicate effectively with co-workers and with management.