ALLSHIFT/docs/04-simulations/rule-based-controller-implementation.md

Rule-Based Controller — MATLAB Implementation

Markdown report of a non-markdown source file.

Source	Shift Matlab Drive/Shift Matlab Drive/controller-claude.m
Format	MATLAB, 92 lines, 7,388 B
MD5	745f573a203238a32cbcd5b1a3d6ecc7
Status	Draft — does not run. See Blocking defects
Report generated	2026-07-25

What it is

The MATLAB implementation of the priority-cascade dispatch policy specified in Rule-Based Controller. Written as the body of a Simulink MATLAB Function block — the signature is function [...] = fcn(...), and fcn is Simulink's default block function name.

function [P_load_P, P_load_PB, P_battery_cont, P_load_PBH, P_FuelCell_cont, P_Electro_cont] = ...
    fcn(Current_A, P_load, P_PV, E_battery_SOC, P_battery_max, E_battery_max, ...
        E_H2_SOC, P_FuelCell_max, E_H2_max)

It resolves load in a fixed merit order, exactly as the specification describes:

Stage	Lines	Behaviour
1. PV direct	8	P_load_P = P_load - P_PV — residual after solar
2. Battery	11–36	Residual > 0 → discharge (capped by P_battery_max or remaining SOC); residual < 0 → charge (capped by max power or remaining headroom)
3. Hydrogen	39–64	Same two-sided pattern — fuel cell discharges the tank, electrolyser charges it
4. Grid	67–72	Whatever remains is bought or sold

Warning

This file does not run. It has hard undefined-variable errors and cannot compile as a Simulink MATLAB Function block. It is an explicitly-marked work in progress — the author's own notes at lines 74–79 say as much. The defect list below is documentation of a known draft, not a code review of something anyone claimed was finished.

Blocking defects

B1 — undefined Electro_max (line 54).

P_Electro_cont = -Electro_max     % The ELECTROLYZER charges at it's maximum power allowed

Electro_max exists nowhere. Intended P_Electro_max — missing the P_ prefix.

B2 — P_Electro_max is never defined either (lines 52, 53, 54).

The signature declares nine inputs; P_Electro_max is not among them and is never assigned in the body. Even after fixing B1, the reference is still undefined. The entire electrolyser branch (lines 51–63) is dead. The function signature needs a tenth input.

B3 — outputs not assigned on all paths.

A Simulink MATLAB Function block requires every declared output to be assigned on every path.

Output	Unassigned when
P_FuelCell_cont / P_Electro_cont	Mutually exclusive — the if at line 39 assigns only the first, the else at 51 only the second. Both are declared outputs
P_load_PB	Never assigned on the path through lines 20–21 (battery too empty to discharge at max)
P_load_PBH	Never assigned on the path through lines 48–49 (tank too empty)

Consequently line 39 can read an unassigned P_load_PB, and line 67 an unassigned P_load_PBH.

Logic defects — silently wrong results

B4 — wrong right-hand side (line 43).

P_FuelCell_cont = P_load_PBH;

The battery analogue it was copied from (line 15) is P_battery_cont = P_load_P; — the incoming residual. Here P_load_PBH is, under the guard at line 42 (P_load_PBH < 0), the negative overshoot. It should read P_FuelCell_cont = P_load_PB;. As written the fuel cell is commanded to a negative power — to consume — exactly when it is supposed to supply.

B5 — sign convention inverted (lines 33 and 61).

The stated convention (line 29) is "negative P_battery_cont is battery charging, positive is discharging". Line 26 respects it (-P_battery_max). But in the same charging branch:

33:  P_battery_cont = E_battery_max - E_battery_SOC;   % headroom — POSITIVE
61:  P_Electro_cont = E_H2_max - E_H2_SOC;             % headroom — POSITIVE

Both assign positive values while on the charging path. Storage will be commanded to discharge when it should charge.

B6 — energy and power conflated throughout.

Energy variables (E_*, kWh) are compared against and assigned to power variables (P_*, kW) with no timestep factor:

Line	Expression	Problem
12	if E_battery_SOC > P_battery_max	kWh compared to kW
21	P_battery_cont = E_battery_SOC;	kWh assigned to a kW command
40	if E_H2_SOC > P_FuelCell_max	kWh compared to kW
49	P_FuelCell_cont = E_H2_SOC;	kWh assigned to a kW command
24, 33, 52, 61	headroom expressions	same

The author flags this at lines 78–79:

%IMPLEMENT THE ARRAY-SCANNING FOR-LOOP AND MAKE SURE THE Power = Energy %Equations make sense????

The arithmetic is only correct if the timestep is exactly 1 h and units are consistent — neither is enforced anywhere. This is the same dt question the Simulator I/O Interface leaves open.

B7 — load sign clashes with Constants.m.

if P_load < 0
    P_load = 0;
end

Constants.m defines E_HospitalLoad = -1000000; %kWh — hospital load is stored negative. If that convention feeds P_load, this guard zeroes out the entire hospital demand and the controller does nothing.

Console output

B8/B9 — two assignments missing a terminating semicolon: line 26 (P_battery_cont = -P_battery_max) and line 54 (P_Electro_cont = -Electro_max). Both echo to the console on every hit, every timestep. An automated scan found exactly these two.

B10 — unconditional disp every timestep (lines 67–72):

if P_load_PBH > 0
    disp('buy')
else
    disp('sell')
end
disp(P_load_PBH)

Beyond the spam, disp is an extrinsic function in a Simulink MATLAB Function block — unsupported for code generation. It will either force interpreted execution or fail the build.

Incomplete sections

I1 — grid exchange is never returned. Lines 67–72 determine buy vs. sell but only print it. There is no output argument for grid power. The author's note at lines 74–76:

%Doublecheck these and repeat the logic for the hydrogen, finally %selling/buying the rest from the grid. Make sure the discharging is at the %tank level and charging at hydrogen level

I2 — the time-series loop was never implemented (lines 78–79, quoted above).

I3 — dead commented-out hydrogen integrator (lines 83–89):

%for t = 1:24                                     %Check if this makes sense
%    H2_stor(end)   = H2_stor(end)*(1-H2_leak);
%    H2_stor(end+1) = H2_stor(end)+H2_vol(t);
%    H2_Flow_L_min(t) = (-P_H2(t)/E_H2_vol_h(t))*(1000/60);
%end
%E_H2_stor = H2_stor*E_H2_vol_h;

Uncommenting it would still fail. H2_stor, H2_vol and P_H2 are undefined anywhere in the repository. H2_leak and E_H2_vol_h do exist — but only in the complete Constants.m, not the stale top-level copy (see Simulink Model Inventory). And line 86 indexes E_H2_vol_h(t) as an array when it is the scalar 3000 — out of bounds for any t > 1.

Other observations

#	Observation
Q1	Input Current_A is declared but never used in the 92-line body — a dead parameter
Q2	The filename is not a legal MATLAB function file. controller-claude.m contains a hyphen; MATLAB identifiers cannot. It can never be called as controller-claude(...). It only works pasted into a Simulink MATLAB Function block — consistent with the function being named fcn
Q3	It is the only file at the Shift Matlab Drive/Shift Matlab Drive/ root, outside Simulations/ entirely, and is not attached to any model in the repository
Q4	The hydrogen block is a verbatim copy of the battery block with incomplete renaming. Lines 45–46 sit in the fuel cell branch but say "max battery power"; line 57 references P_battery_cont inside the electrolyser branch; line 61's comment says "Battery charges only as much as there is space left" while assigning P_Electro_cont. This is how B4 and B5 arose
Q5	Comment typos: dirrectly (7), to empty for "too empty" (20, 48), ELETROLYZER (52), SOTRAGE (60)

Fixing it

In rough dependency order:

1. Add P_Electro_max as a tenth input; fix the Electro_max typo (B1, B2).
2. Assign every output on every path — initialise all six to 0 at the top (B3).
3. Fix line 43 to P_FuelCell_cont = P_load_PB; (B4).
4. Negate lines 33 and 61 (B5).
5. Decide the timestep and make every E_*/P_* conversion explicit (B6).
6. Settle the load sign convention against Constants.m (B7).
7. Add a grid-power output; delete the disp calls (I1, B10).
8. Rename the file to a legal MATLAB identifier, e.g. rule_based_controller.m, and move it next to the model it drives.

Steps 5 and 6 are the ones that need a decision rather than an edit — they are the same open questions the Simulator I/O Interface raises.

Related

• Rule-Based Controller — the specification this implements
• Simulator I/O Interface — the contract, including sign conventions and the dt question
• Simulink Model Inventory — the Constants.m staleness this depends on
• RL Action Variables — what an RL policy would emit instead