SLYR — System-Linked Runtime

SLYR is a modular avionics system for autonomous UAVs, built around a dual-compute architecture that separates real-time flight control from high-level autonomy.

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Overview

SLYR enforces a strict separation of responsibilities:

• STM32 (Flight Kernel) — deterministic, real-time control
• Raspberry Pi (Autonomy Layer) — perception, planning, and decision-making

This design improves system stability, safety, and extensibility while enabling advanced autonomy without compromising control integrity.

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Product Line

SLYR is designed as a unified platform supporting multiple aerial and flight systems:

• SLYR-Q — Quadcopter systems (multirotor UAVs)
• SLYR-F — Fixed-wing aircraft systems
• SLYR-K — Kinetic launch systems (student rockets)

Each series shares the same core runtime and communication architecture while adapting to platform-specific requirements.

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System Architecture

[ Sensors ]
     ↓
[ STM32 Flight Kernel ]
  - State Estimation
  - PID Control
  - Motor Output
     ↓
[ Communication Layer ]
     ↓
[ Autonomy Layer (Raspberry Pi) ]
  - Navigation
  - Perception
  - Decision Engine (SLM)
     ↓
[ Behavior Manager ]
     ↓
[ Control Targets ]
     ↓
[ STM32 Execution ]

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Core Components

Flight Kernel (STM32)

• Real-time control loop (~1 kHz)
• Sensor fusion (IMU, GPS, barometer)
• Attitude and rate PID controllers
• Motor output (DShot / PWM)
• Failsafe and watchdog systems

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Autonomy Layer (Raspberry Pi)

• Waypoint navigation
• Obstacle detection and avoidance
• Mission planning
• Decision engine (SLM-based or rule-based)

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Communication Layer (SLYR Link)

• Custom binary protocol
• UART / SPI transport
• CRC validation
• Heartbeat monitoring and failsafe triggers

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Command Shaping Layer

• Input smoothing (curve-based transitions)
• Rate limiting
• Constraint enforcement

Ensures all control inputs remain within safe operational bounds before execution.

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Control Interface

{
  "roll": 5,
  "pitch": 0,
  "yaw_rate": 20,
  "throttle": 0.6
}

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Mission Definition

{
  "mission": [
    {"lat": 22.1, "lon": 88.5, "alt": 20},
    {"lat": 22.2, "lon": 88.6, "alt": 25, "action": "HOLD"},
    {"lat": 22.3, "lon": 88.7, "alt": 20, "action": "RETURN_HOME"}
  ]
}

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Repository Structure

SLYR/
 ├── firmware/        # STM32 flight kernel (SLYR Core)
 ├── autonomy/        # Raspberry Pi services
 ├── protocol/        # communication specifications (SLYR Link)
 ├── simulation/      # testing and validation tools
 ├── groundstation/   # monitoring and control interface (planned)
 └── docs/            # system documentation and diagrams

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Safety Model

SLYR enforces strict isolation between:

• Decision Layer (autonomy / AI)
• Control Layer (flight kernel)

All incoming commands are:

• validated
• clamped
• smoothed

before being applied to the control system.

The flight kernel retains final authority over actuation.

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Development Roadmap

Phase 1

• Communication layer
• Basic stabilization

Phase 2

• Attitude control
• Manual flight

Phase 3

• GPS-based navigation

Phase 4

• Obstacle detection and avoidance

Phase 5

• AI-assisted decision integration

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Documentation & Updates

For updates, architecture insights, and development logs:

https://slyr.emtypyie.in

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Disclaimer

This project is intended for research and educational use only. Ensure compliance with local regulations before deploying on real hardware.

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Vision

SLYR aims to provide a unified avionics platform combining:

• Real-time embedded systems
• Autonomous navigation
• Intelligent decision-making

for next-generation aerial and space systems.