FA-93806 / Solar tracker geometry / Open access

Dawn and dusk parking positions: wake elevation boundary · case 01

Tracking starts one elevation step later than configured.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The wake comparison includes wake_el itself.

VERIFIED REPAIR

Start tracking at sun_el >= wake_el.

Unsuccessful approach: Starting a degree early tracks while rows would still shade each other.

Case contract

sun_el < 0: [0.0, 'night']. 0 <= sun_el < wake_el: park facing the low sun, [-east_lim, 'dawn'] in the morning (am true) or [west_lim, 'dusk'] in the evening. Otherwise track the ideal angle clamped to the asymmetric limits [-east_lim, west_lim] ('track'). Angles are floats.

Why this case matters

Single-axis and dual-axis solar trackers turn a sun direction into actuator commands; a sign, frame or limit mistake points a whole plant away from the sun or into a mechanical stop.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(ideal, sun_el, am, wake_el, east_lim, west_lim):
    if sun_el < 0:
        return [0.0, 'night']
    if sun_el <= wake_el:
        if am:
            return [-float(east_lim), 'dawn']
        return [float(west_lim), 'dusk']
    return [float(max(-east_lim, min(west_lim, ideal))), 'track']
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [55, 5, True, 5, 50, 60], [55.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [-20, 2, False, 3, 45, 60],
   [60.0, 'dusk']],
  ['control 1', [45, 5, False, 3, 45, 50], [45.0, 'track']],
  ['control 2', [55, 3, True, 3, 50, 50], [50.0, 'track']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [-50, 3, False, 3, 45, 50], [-45.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [15, 2, True, 3, 45, 60],
   [-45.0, 'dawn']],
  ['control 1', [70, 5, False, 3, 50, 50], [50.0, 'track']],
  ['control 2', [0, -6, True, 3, 50, 60], [0.0, 'night']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [55, 3, True, 3, 50, 50], [50.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [15, 2, True, 3, 55, 60],
   [-55.0, 'dawn']],
  ['control 1', [0, 8, True, 5, 55, 50], [0.0, 'track']],
  ['control 2', [-20, 0, False, 5, 55, 50], [50.0, 'dusk']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [-70, 3, True, 3, 45, 60], [-45.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [45, 2, False, 3, 50, 50],
   [50.0, 'dusk']],
  ['control 1', [-20, 3, False, 3, 45, 50], [-20.0, 'track']],
  ['control 2', [45, -6, False, 5, 55, 60], [0.0, 'night']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [15, 5, False, 5, 55, 60], [15.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [-70, 2, False, 3, 45, 60],
   [60.0, 'dusk']],
  ['control 1', [55, 0, True, 5, 45, 60], [-45.0, 'dawn']],
  ['control 2', [-70, -6, True, 5, 55, 50], [0.0, 'night']]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
boundary: sun exactly on horizon	`[-50.0, 'dawn']`	`[-50.0, 'dawn']`	Passed
boundary: sun exactly at wake elevation	`[-50.0, 'dawn']`	`[-50.0, 'track']`	Failed
normal: evening park	`[60.0, 'dusk']`	`[60.0, 'dusk']`	Passed
regression: wake elevation boundary	`[-50.0, 'dawn']`	`[55.0, 'track']`	Failed
regression: wake elevation boundary (partial repair)	`[60.0, 'dusk']`	`[60.0, 'dusk']`	Passed
control 1	`[45.0, 'track']`	`[45.0, 'track']`	Passed
control 2	`[-50.0, 'dawn']`	`[50.0, 'track']`	Failed

SHA-256 / e70064a101ac45db19183a61487e010e89fb7909fb126f144e6c9892d8919ea4

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(ideal, sun_el, am, wake_el, east_lim, west_lim):
    if sun_el < 0:
        return [0.0, 'night']
    if sun_el < wake_el - 1:
        if am:
            return [-float(east_lim), 'dawn']
        return [float(west_lim), 'dusk']
    return [float(max(-east_lim, min(west_lim, ideal))), 'track']
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [55, 5, True, 5, 50, 60], [55.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [-20, 2, False, 3, 45, 60],
   [60.0, 'dusk']],
  ['control 1', [45, 5, False, 3, 45, 50], [45.0, 'track']],
  ['control 2', [55, 3, True, 3, 50, 50], [50.0, 'track']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [-50, 3, False, 3, 45, 50], [-45.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [15, 2, True, 3, 45, 60],
   [-45.0, 'dawn']],
  ['control 1', [70, 5, False, 3, 50, 50], [50.0, 'track']],
  ['control 2', [0, -6, True, 3, 50, 60], [0.0, 'night']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [55, 3, True, 3, 50, 50], [50.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [15, 2, True, 3, 55, 60],
   [-55.0, 'dawn']],
  ['control 1', [0, 8, True, 5, 55, 50], [0.0, 'track']],
  ['control 2', [-20, 0, False, 5, 55, 50], [50.0, 'dusk']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [-70, 3, True, 3, 45, 60], [-45.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [45, 2, False, 3, 50, 50],
   [50.0, 'dusk']],
  ['control 1', [-20, 3, False, 3, 45, 50], [-20.0, 'track']],
  ['control 2', [45, -6, False, 5, 55, 60], [0.0, 'night']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [15, 5, False, 5, 55, 60], [15.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [-70, 2, False, 3, 45, 60],
   [60.0, 'dusk']],
  ['control 1', [55, 0, True, 5, 45, 60], [-45.0, 'dawn']],
  ['control 2', [-70, -6, True, 5, 55, 50], [0.0, 'night']]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
boundary: sun exactly on horizon	`[-50.0, 'dawn']`	`[-50.0, 'dawn']`	Passed
boundary: sun exactly at wake elevation	`[-50.0, 'track']`	`[-50.0, 'track']`	Passed
normal: evening park	`[60.0, 'dusk']`	`[60.0, 'dusk']`	Passed
regression: wake elevation boundary	`[55.0, 'track']`	`[55.0, 'track']`	Passed
regression: wake elevation boundary (partial repair)	`[-20.0, 'track']`	`[60.0, 'dusk']`	Failed
control 1	`[45.0, 'track']`	`[45.0, 'track']`	Passed
control 2	`[50.0, 'track']`	`[50.0, 'track']`	Passed

SHA-256 / 645052ff1e0625e628b9b9eb0b15f2f5987865e984d27648916081b8a0c871fd

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(ideal, sun_el, am, wake_el, east_lim, west_lim):
    if sun_el < 0:
        return [0.0, 'night']
    if sun_el < wake_el:
        if am:
            return [-float(east_lim), 'dawn']
        return [float(west_lim), 'dusk']
    return [float(max(-east_lim, min(west_lim, ideal))), 'track']
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [55, 5, True, 5, 50, 60], [55.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [-20, 2, False, 3, 45, 60],
   [60.0, 'dusk']],
  ['control 1', [45, 5, False, 3, 45, 50], [45.0, 'track']],
  ['control 2', [55, 3, True, 3, 50, 50], [50.0, 'track']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [-50, 3, False, 3, 45, 50], [-45.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [15, 2, True, 3, 45, 60],
   [-45.0, 'dawn']],
  ['control 1', [70, 5, False, 3, 50, 50], [50.0, 'track']],
  ['control 2', [0, -6, True, 3, 50, 60], [0.0, 'night']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [55, 3, True, 3, 50, 50], [50.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [15, 2, True, 3, 55, 60],
   [-55.0, 'dawn']],
  ['control 1', [0, 8, True, 5, 55, 50], [0.0, 'track']],
  ['control 2', [-20, 0, False, 5, 55, 50], [50.0, 'dusk']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [-70, 3, True, 3, 45, 60], [-45.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [45, 2, False, 3, 50, 50],
   [50.0, 'dusk']],
  ['control 1', [-20, 3, False, 3, 45, 50], [-20.0, 'track']],
  ['control 2', [45, -6, False, 5, 55, 60], [0.0, 'night']]],
 [['boundary: sun exactly on horizon', [-70, 0, True, 5, 50, 60], [-50.0, 'dawn']],
  ['boundary: sun exactly at wake elevation', [-50, 5, True, 5, 50, 60], [-50.0, 'track']],
  ['normal: evening park', [55, 2, False, 5, 50, 60], [60.0, 'dusk']],
  ['regression: wake elevation boundary', [15, 5, False, 5, 55, 60], [15.0, 'track']],
  ['regression: wake elevation boundary (partial repair)', [-70, 2, False, 3, 45, 60],
   [60.0, 'dusk']],
  ['control 1', [55, 0, True, 5, 45, 60], [-45.0, 'dawn']],
  ['control 2', [-70, -6, True, 5, 55, 50], [0.0, 'night']]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
boundary: sun exactly on horizon	`[-50.0, 'dawn']`	`[-50.0, 'dawn']`	Passed
boundary: sun exactly at wake elevation	`[-50.0, 'track']`	`[-50.0, 'track']`	Passed
normal: evening park	`[60.0, 'dusk']`	`[60.0, 'dusk']`	Passed
regression: wake elevation boundary	`[55.0, 'track']`	`[55.0, 'track']`	Passed
regression: wake elevation boundary (partial repair)	`[60.0, 'dusk']`	`[60.0, 'dusk']`	Passed
control 1	`[45.0, 'track']`	`[45.0, 'track']`	Passed
control 2	`[50.0, 'track']`	`[50.0, 'track']`	Passed

SHA-256 / 1174591e19b1461e4d6a33da470871bbe27a2e3a7aa926147aad2161461145e8

Verification & scope

Deterministic stipulated toy contract for teaching; no claim of conformance with any standard, vendor protocol or production controller. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:51:58.497136+00:00.

Case digest / 67a4ac1ecc50ce80abaee511d47c51001ed0dcb41f1ce3d4765353069f41d0a6