52 lines
2.8 KiB
Markdown
52 lines
2.8 KiB
Markdown
# components/plant design backlog
|
|
|
|
Findings from reviewing `pot.py`'s water-bath model against real-plant
|
|
behavior (sim/real control mismatch reported by user), refreshed against
|
|
the current `delay`-line rewrite of `Pot`.
|
|
|
|
- [x] **Heat-loss term has wrong units.** Fixed by the `Pot` rewrite:
|
|
`process()` now computes `p_loss = self.L * self.M * (self.temp -
|
|
self.theta_amb)` in Watts and applies `self.temp += (self.delay.get()
|
|
- p_loss) / (self.M * self.C) * self.dt` — the same `/(M*C)`
|
|
normalization for both the gain and loss terms, instead of the old
|
|
mismatched `leak = 1/self.M * self.L * (...)/ self.theta_amb`.
|
|
|
|
- [x] **Thermal lag modeled as single-pole lag, not transport delay.**
|
|
Fixed: `Pot` no longer uses `HeatDiffusion`'s `alpha=dt/Td`
|
|
exponential smoothing (that module was deleted). It now delays the
|
|
input power through `plant/delay.py`'s `Delay` (true dead time)
|
|
before integrating it, matching what this item recommended.
|
|
|
|
- [x] **`kn` is loaded but never applied.** Resolved differently than
|
|
originally proposed: `kn` was removed from `Pot` entirely rather than
|
|
wired up as plant-side measurement noise. Sensor noise is now
|
|
modeled one layer up, in `TempSensorSim` (`temp_offset`/`variance`,
|
|
wired from `brewpi.py`'s `TempSensorFactory.create(..., temp_offset=
|
|
-0.15, variance=0.01)`), not in the plant model. Note: `config.json.templ`
|
|
and `config.json.sim` still carry stale `Model.kn`/`Plant.kn` keys
|
|
that nothing reads anymore — harmless but worth deleting (see
|
|
`components/pid/TODO.md`'s config-validation item).
|
|
|
|
- [x] **`theta_amb` is hardcoded, not configured.** Fixed: added a
|
|
top-level `ambient_temperature` key to `config.json`(`.templ`/`.sim`);
|
|
`brewpi.py` reads it once and passes it to both the real `Pot` and
|
|
(via a new `theta_amb` param) `temp_controller_smith.py`'s internal
|
|
models, so the Smith predictor's model matches the real plant's
|
|
assumed ambient instead of silently defaulting to 20. Real ambient
|
|
temperature still isn't modeled as a *drifting* disturbance (it's a
|
|
static config value, not a live sensor reading), so robustness to
|
|
ambient drift remains untested — that part of the original concern
|
|
stands.
|
|
|
|
- [ ] **No actuator/process realism.** Partially improved: `process()`
|
|
now clamps `self.temp` to `min(100, ...)` (won't simulate past
|
|
boiling), but there's still no heater power saturation enforced
|
|
inside `Pot` itself (handled ad hoc in demo harnesses), no
|
|
evaporation/lid heat loss, and no varying thermal mass `M` as volume
|
|
changes (e.g. boil-off, adding water/grain) — `M` is a fixed
|
|
constant for the whole simulation.
|
|
|
|
- [x] **Debug `print()`s left in `Pot.process()`.** Fixed: the
|
|
unconditional `p_loss`/`theta_amb`/`temp` prints (leftover from the
|
|
heat-loss-units fix) were removed.
|