- a system is controllable iff there is an input u(t) that will cause the system to go from any initial state to any final state in a finite time.
- stabilizable if it is controllable or if the uncontrollable nodes are stable.
- If an input is to be observable it must be detectable in the output. For example consider the following state equations.
• This can be verified with the
• Another test for controllability is,
• Yet another test for controllability is,
• For a system to be controllable, all of the states must be controllable.
• If a system in uncontrollable, it is possible to make it observable by changing the model.
• A pole-zero cancellation is often the cause of the loss of observability.
• if all unstable modes are controllable, the systems is said to be stabilizable.
• The principle of Duality requires that a system be completely observable to be controllable.