Firmus-SDK v1.3.5 Preview

✨ Highlights

• 🤖 Experimental Model Predictive Control (MPC)
  Introduced basic MPC for attitude control with multi-step prediction horizon.

  Note: This feature is still in development and may change in future releases.

• 🧩 Snapshot-Based Policies Upgrade
  IBodyCorrectionPolicy can now operate on full Snapshots, enabling more flexible and modular control strategies.

• 🛠 Modular Control Stack Enhancements
  Existing cascade control layers (BodyPIDPolicy, BodyOrientationLayer, BodyRateLayer) now fully Snapshot-aware, compatible with experimental MPC.

• File structure changes
  The file structure has changed a lot. Sticking to conventional naming patterns ('Assets' > 'tools') and moving hardware tools into its designated folder. mpu6050, ESC, etc... can all be found in /hardware starting from release 1.3.5.

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📚 Notes for Reviewers

• ⚠ Preview Release – Not yet stable, intended for reviewers and testing only.
• All quantities remain in SI units: meters, m/s, radians, rad/s, Nm.
• Reset policies must be applied before switching control modes.
• Control loop frequency is tracked via Snapshot.timestamp and Snapshot.loop_freq.
• The MPC control is a policy, not an entire control layer. It can be used as the correction policy in a Cascade control layer. This is done to support hybrids in the future. Look out for other releases which include hybrid tests.
• The prediction horizon (N) is limited due to matrices being formed in stack, not in heap. Currently N < 5.
• The source code of MPC might come over as hardcoded or underdeveloped, because it is. It's still undergoing massive changes, so stay tuned.
• This release compiles and runs on the DOIT ESP32 Devkit v1, but is still unstable. A lot of bench tests need to be done for it to be declared "plant-ready."

This library is intended to control rigid bodies in open space, hence the torque-output system standard. This includes open-space vehicles such as drones, rockets or submarines. Whether this library will support a wider range of vehicle dynamics (such as ground vehicles—cars, bikes etc...) is unknown. If the request for the inclusion of those dynamics are at a high, I might consider implementing them.

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🛠 Improvements Over v1.3.4

• Added experimental MPC layer for multi-step optimization.
• Snapshot-based IBodyCorrectionPolicy now supports full-state operations.
• Enhanced compatibility between MPC and existing PID cascade layers.
• Minor internal optimizations for Snapshot handling and torque computation.

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⚡ Summary

v1.3.5 Preview introduces the first MPC-capable flow for Firmus-SDK while keeping the modular cascade stack fully compatible.

This release is intended for review and testing, providing early access to advanced control capabilities before a stable v1.3.5 release.

Report issues using the reporting structure provided in the "get started" document provided at ~/docs/get_started.md. Any feedback is greatly appreciated.

Firmus-SDK v1.3.4

✨ Highlights

• Snapshot-Based State Flow
  Introduced the Snapshot structure for full dynamic state encapsulation, enabling more flexible and composable control strategies.

• Modern Control Stack
  Added IBodyCorrectionPolicy, IBodyControlLayer, and IBodyController interfaces for clean, modular cascade control.

• PID Cascade Implementation
  Default layers: BodyPIDPolicy, BodyOrientationLayer, and BodyRateLayer.

  • Independent 3-axis PID control
  • Angular wraparound for yaw
  • Outputs angular velocity and acceleration in Snapshots

• Torque Computation via Rigid Model
  BodyController integrates with IRigidModel for deterministic, physics-based torque calculation.

• Deprecated Legacy Interfaces
  Old interfaces (IAttitude, IVelocity, IPosition, IOrchestrator) are still supported but discouraged in favor of the cascade-based design.

• Hardware-Agnostic Design
  Still runs on ESP32, with abstraction for future STM32 and native C++ support.

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📚 Documentation

• Full example sketches included for cascade control setup.
• README.md and docs/ folder cover interface usage, tuning, and control pipeline configuration.

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🛠 Improvements Over v1.3.3

• Switched from simple Vector3-only PID to Snapshot-capable policies.
• Cleaner modular interfaces for layered control.
• Deterministic torque computation now integrated with BodyController.
• Enhanced internal flow-of-data clarity using Snapshots for orientation, velocity, acceleration, and torque.

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⚡ Summary

v1.3.4 sets the foundation for advanced control strategies, including MPC, LQR, and future Neural Network-based policies, while keeping the SDK modular, predictable, and physics-accurate.

This release is perfect for anyone looking to move beyond simple PID cascades into more flexible and extensible flight control architectures.

Firmus-SDK v1.3.3 – Initial Stable Release

✨ Highlights

• Initial stable release of the Firmus-SDK
• Modular PID control stack: velocity, attitude
• RigidModel<4> with real-time torque + thrust allocation
• Mixer logic with PWM mapping
• Example sketch showing full usage loop
• Static allocation, real-time safe loop (50–100Hz)
• etc...

📚 Documentation

See the docs/ folder, example sketches and README.md for setup, tuning, and control configuration.