MuJoCo : Modular design. Pt: 2

🔧 In this video, we continue building on modular design in MuJoCo by introducing control logic and programmatically accessing sensors and actuators in a clean, scalable way. This follow-up builds on the modular simulation created previously — integrating conveyor belts and pneumatic cylinders — and shows how to access model components using the compiled XML, manage namespaces, and coordinate motion dynamically using sensor feedback. 🎯 Key steps covered: ✔ Printing and analyzing the compiled MuJoCo model ✔ Understanding actuator, sensor, and body naming ✔ Mapping sensor addresses using dimensions ✔ Separating control logic from the MuJoCo template ✔ Writing callback controllers for real-time logic ✔ Detecting object positions using touch sensors ✔ Adjusting velocities and directions based on gear axes ✔ Triggering pneumatic cylinders via sensor feedback 📘 Chapters 00:00 - Introduction & Recap Review of what we covered earlier and what this part adds to the project. 00:06 - Accessing Sensors & Actuators Reading MuJoCo’s compiled model to understand sensor/actuator placement and names. 00:27 - Why Naming is Crucial Using descriptive names for modular clarity and debugging. 00:38 - Reading Sensor Layout How to extract sensor addresses, dimensions, and meaning from the compiled XML. 01:08 - Actuator Parameters Understanding actuator gear configuration for motion control. 01:36 - Setting Up the Controller Splitting code into logic and main, and registering a callback. 01:56 - Using Enums & Helpers Organizing sensor/actuator data with enums for easier access. 02:16 - Writing the Controller Logic Detecting active conveyors, controlling the box's speed and direction. 03:43 - Directional Logic via Gear ⚙️ Whichever conveyor with an active touch sensor becomes the active conveyor. 04:14 - Setting Gear Values for Motion Adjusting motion axes using the actuator gear array. 04:55 - Final Control Flow How velocity and direction shift based on object position. 05:14 - Pneumatic Cylinder Control Triggering cylinder extension via a light sensor on the right side. 05:24 - Compiling & Running the Project How to compile with make, and changes to the Makefile. 05:48 - Simulation Results 🎬 See the full system in motion with varying belt speeds and pneumatic response. 06:11 - Wrap-Up & Files Download the code and model files from GitHub. Thanks for watching! 💡 This is where real-time control meets modular modeling — ideal for simulating complex automation systems in MuJoCo! 📁 Files – https://github.com/felixokolo/MuJoCo_tutorials #MuJoCo #Robotics #ControlLogic #FactorySimulation #PhysicsSimulation #ModularDesign #MuJoCoXML #Automation #DigitalTwin