FPS camera inside player model

Hi !everyone!i have some problem... My player's architecture is a empty gameobject include a player model and camera. My problem is while the model playing animation,the camera will go inside the head of model. Some people solve it with fixing the parameter of Near in camera.It can solve when play idle,walk of animation.But when model run or crouch,camera still go inside model head because its head will move forward more much. So ,how can I solve it?