✨ update urdf and dependencies

src/envs/rotary_cartpole.py

@@ -66,21 +66,14 @@ class RotaryCartPoleEnv(BaseEnv[RotaryCartPoleConfig]):
         ], dim=-1)
 
     def compute_rewards(self, state: RotaryCartPoleState, actions: torch.Tensor) -> torch.Tensor:
-        # height: sin(θ)  → -1 (down) to +1 (up)
-        height = torch.sin(state.pendulum_angle)
+        # Upright reward: -cos(θ) ∈ [-1, +1]
+        upright = -torch.cos(state.pendulum_angle)
 
-        # Upright reward: strongly rewards being near vertical.
-        # Uses cos(θ - π/2) = sin(θ), squared and scaled so:
-        #   down  (h=-1):  0.0
-        #   horiz (h= 0):  0.0
-        #   up    (h=+1):  1.0
-        # Only kicks in above horizontal, so swing-up isn't penalised.
-        upright_reward = torch.clamp(height, 0.0, 1.0) ** 2
+        # Velocity penalties — make spinning expensive but allow swing-up
+        pend_vel_penalty = 0.01 * state.pendulum_vel ** 2
+        motor_vel_penalty = 0.01 * state.motor_vel ** 2
 
-        # Motor effort penalty: small cost to avoid bang-bang control.
-        effort_penalty = 0.001 * actions.squeeze(-1) ** 2
-
-        return 5.0 * upright_reward - effort_penalty
+        return upright - pend_vel_penalty - motor_vel_penalty
 
     def compute_terminations(self, state: RotaryCartPoleState) -> torch.Tensor:
         # No early termination — episode runs for max_steps (truncation only).
@@ -88,7 +81,5 @@ class RotaryCartPoleEnv(BaseEnv[RotaryCartPoleConfig]):
         return torch.zeros_like(state.motor_angle, dtype=torch.bool)
 
     def get_default_qpos(self, nq: int) -> list[float] | None:
-        # The STL mesh is horizontal at qpos=0.
-        # Pendulum hangs down at θ = -π/2 (sin(-π/2) = -1).
-        import math
-        return [0.0, -math.pi / 2]
+        # qpos=0 = pendulum hanging down (joint frame rotated in URDF).
+        return None