Dane Sabo 02a675c152 reachability: first per-mode reach tube and barrier-cert attempt ...

Stand up reachability/ with a hand-rolled zonotope propagator for
linear closed-loop systems (reach_linear.m: axis-aligned box hull,
augmented-matrix integration for the disturbance convolution). Use it
in reach_operation.m to discharge the operation-mode safety obligation:
from a +/-0.1 K box on T_avg, under Q_sg in [85%, 100%]*P0, LQR keeps
T_c within 0.03 K of setpoint over 600 s. Safety band is +/-5 K, so
the obligation is satisfied with five orders of margin.

barrier_lyapunov.m attempts the analytic counterpart via a weighted
Lyapunov function. Sweeping the Qbar(T_c) weight, the best quadratic
barrier allows ~33 K deviation on the gamma level set — still outside
the 5 K safety band. This is a fundamental limitation of quadratic
barriers for anisotropic safety specs (thin-slab safe set in a
precursor-heavy state space). Documented in the file: next step for a
tight analytic certificate is SOS polynomial or polytopic barrier,
which need solvers we don't have locally yet.

reach_linear.m started out with a halfwidth-propagation bug (signed
A_step instead of |A_step|); fixed before commit after noticing the
reach envelope exactly matched the initial box on T_c.

Figures saved to docs/figures/. .mat result files gitignored — they
are regenerated in <1s.

Hacker-Split: first end-to-end per-mode reachability artifact.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

2026-04-17 12:52:37 -04:00

41 KiB

1188x604px

Raw History