Add intervention rate tracking in act_with_policy function

- Introduced counters for tracking intervention steps and total steps during training.
- Calculated and logged the intervention rate at the end of each episode.
- Reset intervention counters after each episode to ensure accurate tracking.

lerobot/scripts/server/actor_server.py

@@ -335,6 +335,9 @@ def act_with_policy(
     list_transition_to_send_to_learner = []
     list_policy_time = []
     episode_intervention = False
+    # Add counters for intervention rate calculation
+    episode_intervention_steps = 0
+    episode_total_steps = 0
 
     for interaction_step in range(cfg.training.online_steps):
         start_time = time.perf_counter()
@@ -372,6 +375,8 @@ def act_with_policy(
             )
 
         sum_reward_episode += float(reward)
+        # Increment total steps counter for intervention rate
+        episode_total_steps += 1
 
         # NOTE: We overide the action if the intervention is True, because the action applied is the intervention action
         if "is_intervention" in info and info["is_intervention"]:
@@ -380,6 +385,8 @@ def act_with_policy(
             # but sometimes for example we want to deactivate the gripper
             action = info["action_intervention"]
             episode_intervention = True
+            # Increment intervention steps counter
+            episode_intervention_steps += 1
 
         # Check for NaN values in observations
         for key, tensor in obs.items():
@@ -424,6 +431,11 @@ def act_with_policy(
             stats = get_frequency_stats(list_policy_time)
             list_policy_time.clear()
 
+            # Calculate intervention rate
+            intervention_rate = 0.0
+            if episode_total_steps > 0:
+                intervention_rate = episode_intervention_steps / episode_total_steps
+
             # Send episodic reward to the learner
             interactions_queue.put(
                 python_object_to_bytes(
@@ -431,12 +443,16 @@ def act_with_policy(
                         "Episodic reward": sum_reward_episode,
                         "Interaction step": interaction_step,
                         "Episode intervention": int(episode_intervention),
+                        "Intervention rate": intervention_rate,
                         **stats,
                     }
                 )
             )
             sum_reward_episode = 0.0
             episode_intervention = False
+            # Reset intervention counters
+            episode_intervention_steps = 0
+            episode_total_steps = 0
             obs, info = online_env.reset()
 
         if cfg.fps is not None: