State Space What does u(.) mean

[dmorris619]

I am trying to understand what is meant by u(.) in control systems, specifically in regards to state space representation. To give context, " Find a control law u(.) which steers the state of" then a the A and B matrices are given (0; 0) to (1; 0) in one unit of time.

I don't need help solving the problem I just want to understand what is meant by u(.)

 

[uart]

u(.) is the input function. When they say "find a control law u(.) ..." they are asking you to find a function u(t) that when applied at the system input achieves some desired output specifications.

 

[dmorris619]

So the dot just means any variable?