How to deal with limit tag when joint limits are changeable (depended on other links) and not fixed?

My robot has not fixed joint limits. On every position is has a different joint limits other side it will hit parent/child link. Or it will go out of working area because I removed support links (closed loop) that are increasing max payload. What I think is to add an extra dummy link to parent/child link to make collision detection and prevent crashing. But i can't deal when it is going out of working area. Can I add a mathematic equation on limits? If not I should add again support links (counterweights for payload), close the open loop, prevent collision with parent links and then it will never go out of working area.. but i find it too difficult to close the open loop. Is there any way to deal with it?