As for the new and delete, when I don't have get the error "undefined reference to `operator new(unsigned int)'" and when looked up, I was told to add the new and delete operators at the top.
Because you tried to use them. I see no need for you to use them.
What is a Sweep?
Sweep doSweep(int inc);
Why is this function defined to return a Sweep object? If it really is supposed to return a Sweep object, why doesn't it?
I think you are making this class far more complex than it needs to be.
servo should be an object, not an instance.
sonar probably should be, too. Hard to say, since you haven't posted the header file.
Can't comment on sweep, since we have no idea what a sweep is.