Published in the Journal of Open Source Software (JOSS)

Tsipor (bird) Dynamics (c4dynamics) is the Python framework for state-space modeling and algorithm development.

Same workflow. Different systems.

Most engineers rebuild everything. c4dynamics keeps the structure fixed.

c4dynamics is a Python framework for building, simulating, estimating, and controlling physical systems — without resetting your workflow every time the system changes.

It gives you one consistent way to:

• define a system
• simulate its evolution
• estimate its state
• design control

Across:

robotics · aerospace · autonomous systems · navigation

Real implementations of modeling, estimation, and control

These are not isolated demos. They all follow the same structure.

6-DOF Simulation Proportional navigation guidance

Extended Kalman Filter Ballistic coefficient estimation

Detection + Kalman Filter Vehicle tracking

Model Predictive Control Vehicle steering

Quadcopter Cascade PID Figure-8 trajectory tracking

Switching systems shouldn’t feel like starting over.

But it does:

• new models
• new simulation structure
• new estimation logic
• new control pipeline

You don’t just learn new physics.

You rebuild everything.

Keep the workflow. Change the physics.

c4dynamics enforces a consistent structure:

define → simulate → estimate → control

So when the system changes:

your thinking doesn’t.

Physics first. Programming second.

• Code implements
• Models define reality
• Algorithms follow structure

• state-based modeling primitives
• simulation infrastructure
• Kalman / Extended Kalman filters
• sensor and detection modules
• reinforcement learning environments
• OpenCV / Open3D integration
• Monte Carlo simulation support

• control engineers
• robotics engineers
• aerospace engineers
• autonomy developers

Especially if you’ve felt:

“I know this stuff… but I don’t use it.”

>>> import c4dynamics as c4d

s = c4d.state(y=1, vy=0.5)

F = [[1, 1],
     [0, 1]]

s.X += F @ s.X
s.store(t=1)

• 3.8 <= Python < 3.13
• Required packages are listed in requirements.txt

For detailed instructions on installing c4dynamics, including setup for virtual environments, Python version requirements, and troubleshooting, refer to the c4dynamics setup guide.

• PIP

>>> pip install c4dynamics

• GitHub

To run the latest GitHub version, download the repo and install required packages:

>>> pip install -r requirements.txt

📘 https://c4dynamics.github.io/c4dynamics/

• concepts
• API
• examples
• tutorials

This is not just a library.

It’s a shared way of building systems.

• build examples
• improve structure
• explore new systems

If you encounter problems, have questions, or would like to suggest improvements, please open an Issue in this repository.

New system. Same workflow.