Model Predictive Controller only works for certain values

[odow]

I can’t reproduce your issues, because I don’t know the arguments to your function. Take a read of: Please read: make it easier to help you

Some things that might help:

• use fix(phi[1] init_phi) instead of adding the initial value constraints.
• Add sensible bounds on phi, theta, and u
• Consider rewriting phi and theta as a @NLexpression instead of a variable. (It seems your only real decision variable is u.) For example, something like:

  phi = [@NLexpression(model, init_phi)]
  for i in 2:num_time_steps
      push!(phi, @NLexpression(model, phidot[i - 1] * h + phi[i - 1]))
  end