feat(exp24): discrete steering + speed-based stuck detection

StuckTerminationWrapper: add low_speed_threshold + max_low_speed_seconds params.
Car pinned against a barrier has speed≈0 even while sliding laterally — lateral
drift was resetting the position-based displacement timer, leaving the car stuck
for up to max_episode_seconds. Speed-based check terminates after 2s at speed<0.5.

Exp24: 7-bin discrete steering (DiscretizedActionWrapper) eliminates Gaussian policy
noise that caused rapid oscillation in exp23. max_episode_seconds reduced to 30s
since speed-based stuck detection now handles the barrier-contact cases.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Paul Huliganga 2026-05-05 17:41:42 -04:00
parent c05e79d30c
commit 924615ca60
2 changed files with 299 additions and 13 deletions

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@ -0,0 +1,259 @@
"""
Exp 24: Discrete steering + speed-based stuck detection.
What changed from exp23:
- Discrete action space: 7 steering bins × 1 throttle = 7 actions.
Eliminates Gaussian policy noise that caused rapid steering oscillation.
Bins: steer {-1, -0.67, -0.33, 0, 0.33, 0.67, 1}, throttle=0clamped to 0.2.
- Speed-based stuck detection: if speed < 0.5 m/s for 2 wall-clock seconds
terminate. Catches car pinned against a barrier regardless of lateral sliding
(lateral drift was resetting the position-based timer in exp23, leaving the car
against the wall for up to max_episode_seconds).
- max_episode_seconds reduced to 30s (stuck detection catches the bad cases faster;
120s was a consequence of stuck detection not working, not a design choice).
- Single track: generated_road on port 9091.
- Fresh PPO (MlpPolicy not CnnPolicy Discrete action space, same CNN obs encoder).
- Total steps: 200k.
"""
import os
import sys
import time
from datetime import datetime
sys.path.insert(0, '/home/paulh/projects/donkeycar-rl-autoresearch/agent')
_SAVE_DIR = '/home/paulh/projects/donkeycar-rl-autoresearch/agent/models/exp24-discrete'
_PIDFILE = os.path.join(_SAVE_DIR, 'current.pid')
os.makedirs(_SAVE_DIR, exist_ok=True)
if os.path.exists(_PIDFILE):
try:
_old = int(open(_PIDFILE).read().strip())
if _old != os.getpid():
import signal
os.kill(_old, 0)
print(f'[exp24] Another instance already running (PID {_old}). Exiting.', flush=True)
sys.exit(1)
except (OSError, ValueError):
pass
import gymnasium as gym
import numpy as np
from stable_baselines3 import PPO
from stable_baselines3.common.vec_env import DummyVecEnv, VecTransposeImage
from discretize_action import DiscretizedActionWrapper
from donkeycar_sb3_runner import ThrottleClampWrapper
from multitrack_runner import StuckTerminationWrapper
from reward_wrapper import SpeedRewardWrapper
HOST = 'localhost'
THROTTLE_MIN = 0.2
LR = 0.0003
TOTAL_STEPS = 200_000
CHECKPOINT_EVERY = 10_000
N_STEER = 7 # steering bins: -1, -0.67, -0.33, 0, 0.33, 0.67, 1
N_THROTTLE = 1 # fixed at 0.0 → clamped to THROTTLE_MIN by ThrottleClampWrapper
# Reward wrapper params (same as exp23 v7)
EFFICIENCY_WINDOW = 30
MIN_EFFICIENCY = 0.15
MAX_CTE = 8.0
MIN_LAP_TIME = 12.0
PROGRESS_PATIENCE = 100
# StuckTerminationWrapper — speed-based check is the primary stuck detector now
MAX_STUCK_SECONDS = 5.0 # position-based: 0.5m displacement timer
MAX_EPISODE_SECONDS = 30.0 # hard cap (reduced from 120s — speed check handles it)
LOW_SPEED_THRESHOLD = 0.5 # m/s — below this counts as "stuck"
MAX_LOW_SPEED_SECONDS = 2.0 # seconds at low speed before termination
def log(msg):
print(f'[{datetime.now().strftime("%H:%M:%S")}] {msg}', flush=True)
def make_env(track_id, port):
def _init():
raw = gym.make(track_id, conf={'host': HOST, 'port': port})
env = ThrottleClampWrapper(raw, throttle_min=THROTTLE_MIN)
env = DiscretizedActionWrapper(env, n_steer=N_STEER, n_throttle=N_THROTTLE)
env = StuckTerminationWrapper(
env,
stuck_steps=40,
min_displacement=0.5,
max_stuck_seconds=MAX_STUCK_SECONDS,
max_episode_seconds=MAX_EPISODE_SECONDS,
low_speed_threshold=LOW_SPEED_THRESHOLD,
max_low_speed_seconds=MAX_LOW_SPEED_SECONDS,
)
env = SpeedRewardWrapper(
env,
window_size=EFFICIENCY_WINDOW,
min_efficiency=MIN_EFFICIENCY,
max_cte=MAX_CTE,
min_lap_time=MIN_LAP_TIME,
progress_patience=PROGRESS_PATIENCE,
)
return env
return _init
def make_eval_env(track_id, port):
inner = make_env(track_id, port)()
return VecTransposeImage(DummyVecEnv([lambda e=inner: e]))
log('=' * 60)
log('Exp 24: generated_road — discrete steering, speed-based stuck')
log(f' Sim: {HOST}:9091 -> generated_road')
log(f' Discrete steering: {N_STEER} bins, throttle fixed at {THROTTLE_MIN}')
log(f' throttle_min={THROTTLE_MIN}, lr={LR}, total={TOTAL_STEPS:,}')
log(f' Reward: v7 (speed×CTE, efficiency gate, no-progress kill)')
log(f' Stuck: position≥0.5m/{MAX_STUCK_SECONDS}s OR speed<{LOW_SPEED_THRESHOLD}/{MAX_LOW_SPEED_SECONDS}s')
log(f' Episode cap: {MAX_EPISODE_SECONDS}s (safety net)')
log(f' Checkpoints every {CHECKPOINT_EVERY:,} steps')
log('=' * 60)
log('Creating DummyVecEnv on generated_road...')
env = DummyVecEnv([make_env('donkey-generated-roads-v0', 9091)])
env = VecTransposeImage(env)
log(f' VecEnv num_envs={env.num_envs}, obs={env.observation_space.shape}')
log(f' Action space: {env.action_space}')
model = PPO(
'CnnPolicy',
env,
learning_rate=LR,
n_steps=2048,
batch_size=64,
n_epochs=10,
gamma=0.99,
gae_lambda=0.95,
clip_range=0.2,
ent_coef=0.01,
verbose=1,
device='cpu',
)
with open(_PIDFILE, 'w') as f:
f.write(str(os.getpid()))
log(f'Fresh PPO model created (Discrete({N_STEER * N_THROTTLE}) actions). Starting training...')
best_total_steps = float('-inf')
best_total_reward = float('-inf')
steps_done = 0
run_tag = datetime.now().strftime('%Y-%m-%d_%H%M%S') + '_discrete'
log_path = os.path.join(_SAVE_DIR, f'run_{run_tag}.log')
best_model_path = os.path.join(_SAVE_DIR, 'best_model.zip')
import logging
logging.basicConfig(
level=logging.INFO,
format='%(message)s',
handlers=[logging.FileHandler(log_path), logging.StreamHandler(sys.stdout)],
)
file_log = logging.getLogger('exp24')
def flog(msg):
ts = datetime.now().strftime('%H:%M:%S')
file_log.info(f'[{ts}] {msg}')
flog('=' * 60)
flog(f'Exp 24 started — PID {os.getpid()}')
flog(f'Log: {log_path}')
flog('=' * 60)
while steps_done < TOTAL_STEPS:
seg_steps = min(CHECKPOINT_EVERY, TOTAL_STEPS - steps_done)
model.learn(total_timesteps=seg_steps, reset_num_timesteps=False)
steps_done += seg_steps
ckpt = os.path.join(_SAVE_DIR, f'checkpoint_{steps_done:07d}')
model.save(ckpt)
model.save(os.path.join(_SAVE_DIR, 'model'))
flog(f'[{steps_done:,}/{TOTAL_STEPS:,}] Checkpoint saved: {ckpt}.zip')
try:
obs = env.reset()
ep_rewards = np.zeros(env.num_envs)
ep_steps = np.zeros(env.num_envs)
done_mask = np.zeros(env.num_envs, dtype=bool)
for _ in range(2000):
action, _ = model.predict(obs, deterministic=True)
obs, rewards, dones, infos = env.step(action)
for i in range(env.num_envs):
if not done_mask[i]:
ep_rewards[i] += rewards[i]
ep_steps[i] += 1
if dones[i]:
done_mask[i] = True
if done_mask.all():
break
total_steps_eval = int(ep_steps.sum())
total_reward_eval = float(ep_rewards.sum())
status = '' if ep_steps[0] >= 2000 else f'❌@{int(ep_steps[0])}'
flog(f' Eval: gen_road={total_reward_eval:.1f}r/{int(ep_steps[0])}s {status}')
if (total_steps_eval > best_total_steps
or (total_steps_eval == best_total_steps
and total_reward_eval > best_total_reward)):
best_total_steps = total_steps_eval
best_total_reward = total_reward_eval
model.save(best_model_path)
flog(f' NEW BEST: steps={best_total_steps} reward={best_total_reward:.1f}')
except Exception as e:
flog(f' Eval error: {e}')
env.close()
flog('=' * 60)
flog('FINAL EVALUATION: best_model on generated_road')
flog('=' * 60)
EVAL_SETS = 3
EVAL_MAX_STEPS = 2000
steps_list = []
reward_list = []
for s in range(1, EVAL_SETS + 1):
try:
eval_env = make_eval_env('donkey-generated-roads-v0', 9091)
eval_model = PPO.load(best_model_path, env=eval_env, device='cpu')
obs = eval_env.reset()
done = False
total_s = 0
total_r = 0.0
while not done and total_s < EVAL_MAX_STEPS:
action, _ = eval_model.predict(obs, deterministic=True)
result = eval_env.step(action)
obs, r, done = result[0], result[1], result[2]
if hasattr(done, '__len__'):
done = bool(done[0])
total_r += float(r) if not hasattr(r, '__len__') else float(r[0])
total_s += 1
status = '' if total_s >= EVAL_MAX_STEPS else f'❌@{total_s}'
flog(f' Set {s}: {total_r:.1f}r / {total_s}s {status}')
steps_list.append(total_s)
reward_list.append(total_r)
eval_env.close()
except Exception as e:
flog(f' Set {s} error: {e}')
if steps_list:
flog(f' Mean: {np.mean(steps_list):.0f} steps / {np.mean(reward_list):.1f} reward')
flog('Exp 24 complete.')

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@ -134,31 +134,40 @@ class StuckTerminationWrapper(gym.Wrapper):
can take 1+ minutes of wall-clock time. The wall-clock timeout catches
this case regardless of sim speed.
Handles two cases the sim misses:
1. Car pressed slowly against a barrier Unity's hit detection needs a
velocity threshold; slow contact leaves hit='none' and episode open.
2. Car circling off the start/finish line efficiency0 gives zero reward
Handles three cases the sim misses:
1. Car pressed slowly against a barrier Unity's OnCollisionEnter fires
once then resets; Python never sees sustained contact. Speed-based check
terminates after max_low_speed_seconds at speed < low_speed_threshold.
2. Car sliding laterally along a barrier position displacement > 0.5m
keeps resetting the wall-clock timer; speed stays 0. Speed-based check
catches this; position-based check cannot.
3. Car circling off the start/finish line efficiency0 gives zero reward
but the episode never ends, wasting training steps with no signal.
When stuck is detected: terminated=True so SpeedRewardWrapper returns -1.0.
"""
def __init__(self, env, stuck_steps: int = 80, min_displacement: float = 0.5,
max_stuck_seconds: float = 12.0, max_episode_seconds: float = 30.0):
max_stuck_seconds: float = 12.0, max_episode_seconds: float = 30.0,
low_speed_threshold: float = 0.5, max_low_speed_seconds: float = 3.0):
super().__init__(env)
self.stuck_steps = stuck_steps
self.min_displacement = min_displacement
self.max_stuck_seconds = max_stuck_seconds
self.max_episode_seconds = max_episode_seconds
self._pos_buf: deque = deque(maxlen=stuck_steps)
self._last_progress_pos = None
self._last_progress_t = None
self._episode_start_t = None
self.stuck_steps = stuck_steps
self.min_displacement = min_displacement
self.max_stuck_seconds = max_stuck_seconds
self.max_episode_seconds = max_episode_seconds
self.low_speed_threshold = low_speed_threshold
self.max_low_speed_seconds = max_low_speed_seconds
self._pos_buf: deque = deque(maxlen=stuck_steps)
self._last_progress_pos = None
self._last_progress_t = None
self._episode_start_t = None
self._low_speed_start_t = None
def reset(self, **kwargs):
self._pos_buf.clear()
self._last_progress_pos = None
self._last_progress_t = None
self._episode_start_t = time.time()
self._low_speed_start_t = None
return self.env.reset(**kwargs)
def step(self, action):
@ -197,6 +206,24 @@ class StuckTerminationWrapper(gym.Wrapper):
except (TypeError, ValueError):
pass
# Speed-based stuck detection: catches car pinned against a barrier.
# A car pressed against a wall has speed≈0 even while sliding laterally
# (accumulating displacement that resets the position-based timer above).
if not terminated:
try:
speed = float(info.get('speed', 999.0) or 999.0)
except (TypeError, ValueError):
speed = 999.0
if speed < self.low_speed_threshold:
if self._low_speed_start_t is None:
self._low_speed_start_t = now
elif (now - self._low_speed_start_t) > self.max_low_speed_seconds:
terminated = True
info['stuck_termination'] = True
info['stuck_reason'] = 'low_speed_timeout'
else:
self._low_speed_start_t = None
# Hard episode wall-clock limit — fires regardless of car position or sim fps.
# Catches cars sliding slowly along barriers that keep resetting the
# max_stuck_seconds timer by drifting 0.5m at a time.