We have many objectives when we design such systems. We have to minimize wear, we have to avoid dangerous vibrations, we also have to limit the cam torque, and many other performance indexes that we will deal later.
Also we have to choose a number of parameters, say many parameters. For example, the stiffness of the return spring of the valve, the pre-load of the spring, the cam radius, other kinematical parameters, the lubricant and so on. So the problem appears to be complex and we have to resort to Multi-objective Programming to solve it.