Exp 17 post-mortem: efficiency gate window=30 steps only covers ~40% of a
3.5s exploit circle at 22fps, giving partial-arc efficiency ~0.77 (gate fires
at 0.15). Car earned positive reward while circling, outweighing the -10
lap penalty. Performance peaked at 80k then collapsed.
Exp 18 fixes:
- window_size 30→200: covers 2+ full exploit circles, driving efficiency→0
- min_lap_time 5s→12s: genuine laps are 13-16s (gentrack) and 27-29s (mountain);
anything under 12s is an exploit and terminates immediately
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- exp17_parallel_450k.py: parallel two-track training (generated_track:9091,
mountain_track:9093), 450k steps, v6 reward, HOST=localhost
- DECISIONS.md: ADR-025 (parallel strategy) and ADR-026 (mountain friction fix)
- docs/STATE.md: updated to April 2026 state with current champions and strategy
- docs/TEST_HISTORY.md: mountain friction fix notes + Exp 17 full design
- outerloop-results: exp14 finetune logs and robust mountain eval results
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
v5 required for mountain hills (v4 gives zero gradient on hills - documented Exp 1).
Same simple approach as Exp 13 which worked: single track, minimal wrappers,
lap-based stopping. ThrottleClamp + V5Reward only.
Return to Wave 4 setup that produced Trial 9 (2000/2000 on generated_track).
v4 reward: base x efficiency x speed. Circles give ~0 reward naturally.
No StuckTerminationWrapper, no CTE patience, no progress terminator.
Just ThrottleClamp + V4Reward. Lap-based stopping criterion.
User's insight: a circling car stays near the same track waypoints, so
active_node (sim's track progress indicator) never advances. Track the
maximum active_node reached this episode. If it hasn't increased in
progress_patience=60 steps (~3.3s), terminate.
This catches:
- Circular driving (active_node oscillates, max never increases)
- Stuck on cone/barrier (active_node frozen)
- NOT triggered by: legitimate cornering, slow forward progress, lap resets
On lap completion, active_node wraps to 0 — reset max_node_seen and counter.
Also: Exp 12 — single track mountain training with lap-based stopping criterion.
Train until 3 consecutive laps in eval, not fixed step count.
Critical facts documented permanently:
- throttle_min=0.5 bakes into action space (too fast for corners)
- throttle_min=0.2 + v5 reward CAN learn hill (proved Exp 9, mountain only 90k)
- Mountain failure in parallel is contamination from grass exploit, not throttle
- Grass exploit root cause: sim determine_episode_over() passes when CTE>16m
- DO NOT confuse mountain rollback with stuck issue
- DO NOT change throttle_min as first response to mountain failure
v5 dropped the efficiency term to get gradient signal on hills, but this
re-enabled circular driving (observed in Exp 11). v6 adds efficiency back
as a GATE (not multiplier): if efficiency < 0.15, reward = 0. Otherwise
reward = speed × CTE_quality (same as v5).
Gate vs multiplier: v4 used efficiency as a multiplier which killed gradient
on hills (all terms → 0 simultaneously). v6's gate passes when efficiency
is above threshold (car moving forward, even slowly on hill) and only
blocks when car is truly circling.
Also reduced stuck_steps from 80 to 40 (~2.5s vs ~5s) — user reported
car stuck against barriers for ~10s which is too long with DummyVecEnv.
Scripts in /tmp are lost on reboot and not reproducible.
All experiment scripts now committed to git with README.
Exp5 script was already gone (lost before this fix).
All others (Exp6-Exp10, overnight, wave5, etc.) now preserved.
Rule going forward: scripts saved to agent/experiments/ and committed
BEFORE running, not after.
Agent: pi
Tests: 102 passed
Tests-Added: 0
TypeScript: N/A
Paul Huliganga