【Control】🛡️ 18. AI Control Safety Design Checklist

― Safety Envelope, Stop Logic, and Recovery (Pre-Implementation Review)

topics: [“control”, “AI”, “safety design”, “FSM”]

🎯 Purpose of This Article

This article provides a mandatory safety design checklist
to be reviewed before deploying AI-assisted control systems into real operation.

Philosophy / background: ❌
Inspirational discussion: ❌

👉 The goal is direct use in design reviews, safety audits, and approval processes.

🧱 Mandatory Safety Architecture (3 Required Elements)

Safe AI control requires all three of the following:

🟦 Safety Envelope (never exceed)
🟥 Stop Logic (force stop)
🟩 Recovery Control (safe return)

Missing any one of these → deployment not allowed.

🗺️ Safety Design Flow (Overall State Diagram)

stateDiagram-v2
    [*] --> Normal

    Normal --> Warning : Envelope approaching
    Warning --> Safe : Boundary exceeded
    Safe --> Diagnostic : State stabilized
    Diagnostic --> Limited : Cause isolated
    Limited --> Normal : Conditions restored

    %% Forbidden transitions
    Safe --> Normal : FORBIDDEN
    Diagnostic --> Normal : FORBIDDEN

🟦 1. Safety Envelope (Mandatory)

✅ Definition Checklist

Item	Defined	Notes
Monitored state variables	⬜	Position / velocity / voltage / current
Upper & lower bounds	⬜	Hard limits
Rate-of-change limits	⬜	d/dt constraints
Time-in-state limits	⬜	Timeout rules

📐 Design Rules (Mandatory)

✅ Defined by humans
✅ Fixed constants
❌ Updated by AI or learning

👉 The Safety Envelope must never be a learning target.

🟥 2. Stop Logic (Mandatory)

🔍 Typical Decision Metrics

Metric	Meaning
Δt / Δt₀	Response time ratio
Kp / Kp₀	Gain compensation ratio
A / A₀	Amplitude ratio

⚙️ Decision Logic Example

if metric > threshold:
    ADAPT_STOP

✅ Requirements

Deterministic
Numerically explainable
Fully logged and traceable

🧯 3. Recovery Control (Mandatory)

🧩 Required Modes

Mode	Role
Safe	Minimum output, guaranteed behavior
Diagnostic	Root-cause isolation
Limited	Constrained recovery
Normal	Standard operation

🚫 Forbidden Transitions (Critical)

❌ Safe → Normal
❌ Diagnostic → Normal
❌ AI-based recovery decisions

👉 Recovery must always be gradual.

🧠 LLM Usage Constraints (Safety Requirement)

✅ Allowed

Root-cause analysis
Log summarization
Design improvement proposals

❌ Forbidden

Safety judgment
Stop decisions
Recovery decisions

🚫 Immediate Disqualification (NG Designs)

❌ Learning the Safety Envelope
❌ Treating stop as a warning only
❌ Automatic immediate recovery
❌ No logging of boundary violations

✅ Final Acceptance Criteria

All three must be YES:

☑ Cannot exceed limits (Envelope)
☑ Can forcibly stop (Stop Logic)
☑ Can safely return (Recovery Control)

📌 Final Specification Summary

Safety boundary: 🟦 Safety Envelope
Stop decision: 🟥 FSM (deterministic)
Recovery design: 🟩 Gradual return

👉 Any AI control system missing these is not deployable.

🔜 Next Article

19. Applicability Limits of Adaptive Control
— Quantitative results for A-Type and B-Type (tables and diagrams)