Is there a method that can be used for very large number of operating points to design PID controller ?

Hello Everyone,
I have a plant(DC-DC Booster) that is driving a load that has very large number of operating point. I have a PID that is implemented in Micro-controller in C language.
I used gain scheduling method for the moments.But, I am still looking for another method that can be used to tune the PID parameters for all the operating points of my plants without running into overshoot or being too slow.
From your description it appears you have an existing PID controller that could perform better.
Can the variables be easily accessed / changed ?
What are the operating points and in what form are they available - can you draw a graph or otherwise trend them ?
What do you mean by gain scheduling ?
Yes I already have a PID controller that uses the gain scheduling method which means for each operating point I have a PI parameters that I stored in look up table. depending on the load.
the operating point are different value of load resistors (wide range)