Deterministic Sub-Microsecond Safety Layer for Edge AI & Robotics
MicroSafe-RL is an ultra-lightweight, bare-metal C++ interceptor designed to protect physical hardware from Reinforcement Learning (RL) instability and Edge LLMs "hallucinations".
RL policies trained in simulation often produce out-of-range commands when deployed on real hardware. This library "clamps" these commands deterministically in O(1) time before they reach the execution engine.
| Metric | Value |
|---|---|
| Worst-Case Latency (WCET) | 1.18 µs (Cortex-M3 @ 72 MHz) |
| RAM Footprint | 24 bytes, zero dynamic allocation |
| Compliance | MISRA-C:2012 (Zero Critical Violations) |
| Complexity | O(1) constant time per step |
See MicroSafe-RL in action, preventing critical failure in real time:
The interceptor monitors the signal behavior using an Exponential Moving Average (EMA). When the input command deviates significantly from the established baseline, a "gravity factor" is applied to smoothly return the command to the safe operating zone.
Hard Shield: The hard clip (min_limit / max_limit) is always active from the very first step, ensuring safety even before the EMA has collected sufficient history.
MicroSafe-RL now includes a Python-C++ Bridge that enables seamless and safe connection with local Large Language Models.
- Using Ollama (Gemma 4, Llama 3.2, Phi-4, Mistral, etc.) as a robotic controller
- Running local vision-language models for perception + reasoning
- Edge LLM agents that output high-level actions (velocity, torque, joint targets)
The bridge forwards the LLM-generated action to MicroSafe-RL, which applies deterministic safety clamping before the command reaches the hardware. This combination gives you the flexibility and intelligence of a local LLM while maintaining sub-microsecond physical safety guarantees.
import ollama
from microsafe_bridge import MicroSafeBridge
safety_bridge = MicroSafeBridge(
model_name="gemma:2b", # or any local model via Ollama
safety_params={"kappa": 0.078, "alpha": 0.55, ...}
)
while True:
prompt = get_current_observation() # sensor data, camera, etc.
response = ollama.chat(model="gemma:2b", messages=[{"role": "user", "content": prompt}])
try:
ai_action = parse_action(response['message']['content']) # extract float/vector
safe_action = safety_bridge.apply(ai_action) # MicroSafe-RL protection
actuator_command(safe_action)
except:
# fallback to safe default
actuator_command(0.0)
## 📊 Benchmark Results
Tested against a Kalman-filter detector and a PLC threshold system across 120 scenarios (runaway, adversarial, and safe conditions).
| System | Mean Detection Margin (steps before failure) | Std Dev |
|---------------------|----------------------------------------------|---------|
| **MicroSafe-RL** | 19.2 | ±1.4 |
| Kalman-filter | 11.0 | ±1.6 |
| PLC threshold | 8.0 | ±0.7 |
**Hardware Validation** (Arduino Uno + MPU-6050):
Average end-to-end intercept latency — 3.2 ms, with **1.18 µs** pure computational latency of the protection algorithm.
## 🧪 Integration Example (Embedded C++)
```cpp
#include "MicroSafeRL_misra.h"
// Parameters: kappa, alpha, decay, beta, g, min, max, vel_weight
MicroSafeRL safety(0.078f, 0.55f, 2.2f, 0.12f, 1.0f, -1.5f, 1.5f, 0.05f);
void loop() {
float safe_val = safety.apply_safe_control(ai_action, sensor_val);
float reward = safety.get_current_reward();
actuator.set(safe_val);
agent.update(reward);
}
⚠️ Limitations
Warm-up Period: EMA requires approximately 20 calibration steps. During this time, only the hard clip is active.
Hardware Protection: This is a software safety layer and does not replace physical protections such as fuses and current limiters.
Tuning: Parameters (κ, α, g, etc.) significantly affect behavior and should be profiled for the specific hardware.
🔬 Academic Status
Submitted for Review:
"A Control Lyapunov Metric for Autonomous Fault Recovery in Embedded and Aerospace Systems" — IEEE Transactions on Aerospace and Electronic Systems.
Preprint:
Kretski, D. (2026). ORAC-NT v5.x: Optimal and Stable FDIR Architecture. Zenodo.
DOI: 10.5281/zenodo.19019599
📬 Licensing
MIT License for academic and non-commercial use.
For production deployment in safety-critical systems, please contact: kretski1@gmail.com
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