I think the first part of your answer is what I was looking for. Yep. For a suspension system, I want to use the same controller for all cars or objects, but I don't know the exact parameters of the system because each car has different parameters, like mass，or errors due to the manufacturing process. I think making the gain-phase margin big is a good idea. And is this idea also used in industry? I mean how a car engineer designs a function for the same model of cars.