Apply_forces not work

I am new to isaac-sim, when I call RigidPrimView.apply_forces() or RigidPrim._rigid_prim_view.apply_forces(), it is not work, the rigid body is not moving at all, how can I fix it?

that is the way I use it:

class Quadcopter(RigidPrim):

    def __init__(self, ):
        self._body_prim_path = prim_path + "/base_link"
        super().__init__(prim_path=self._body_prim_path, name=name)
    def initialize(self, physics_sim_view):
    def step(self):
       forces = torch.zeros((1, 3))
        forces[:, 2] = 100
        self._rigid_prim_view.apply_forces(forces=forces) # not work when call, the rigid body is stick to the ground

I can’t be sure of what is not working in your case given that there are many other parameters involved that aren’t clear from the question. I can take a closer look if you could provide a minimal working example that I can use to replicate the issue