I think you misunderstand how these tools work, and the meaning of a boundary.
The bounds (lb and ub) are fixed, whatever you set them at the start. They cannot change for each iteration, based on your whim, or on the weather outside.
Next, you cannot have a constraint like c>0. You can only have a constraint of the form c>=0, and even that may be violated by a tiny amount (TolCon).
Perhaps you meant something else. If so, then you need to explain your question far more clearly.
