RDC_Simulation/docs/pybullet.md

PyBullet Simulation

Running the GPS-denied drone simulation with PyBullet.

Windows (Standalone Mode)

No ROS 2 required! Run the all-in-one simulation:

. .\activate.ps1
python standalone_simulation.py

Options

# Stationary landing pad
python standalone_simulation.py

# Moving rover patterns
python standalone_simulation.py --pattern circular --speed 0.3
python standalone_simulation.py --pattern linear --speed 0.5
python standalone_simulation.py --pattern square --speed 0.4

Options:
  --pattern, -p   stationary, linear, circular, square
  --speed, -s     Rover speed in m/s (default: 0.5)
  --amplitude, -a Movement amplitude in meters (default: 2.0)

The simulation includes a built-in landing controller. Watch the drone automatically land on the rover!

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Linux (Full ROS 2 Mode)

Terminal 1 - Simulator:

source activate.sh
python simulation_host.py

Terminal 2 - ROS Bridge:

source activate.sh
python ros_bridge.py

Terminal 3 - Controllers:

source activate.sh
python controllers.py --pattern circular --speed 0.3

Remote Setup

Run simulator on one machine, controllers on another.

Machine 1 (with display):

python simulation_host.py

Machine 2 (headless):

source activate.sh
python ros_bridge.py --host <MACHINE_1_IP>
python controllers.py

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Simulation Parameters

Parameter	Value
Physics Rate	240 Hz
Telemetry Rate	24 Hz
Drone Mass	1.0 kg
Gravity	-9.81 m/s²

GPS-Denied Sensors

Sensor	Description
IMU	Orientation, angular velocity
Altimeter	Barometric altitude, vertical velocity
Velocity	Optical flow estimate
Camera	320x240 downward JPEG image
Landing Pad	Vision-based relative position

Camera System

Property	Value
Resolution	320 x 240
FOV	60 degrees
Format	Base64 encoded JPEG
Direction	Downward-facing

World Setup

Object	Position	Description
Ground	z = 0	Infinite plane
Rover	(0, 0, 0.15)	1m × 1m landing pad
Drone	(0, 0, 5)	Starting position

Building Executable

Create standalone executable:

source activate.sh
python build_exe.py

Troubleshooting

"Cannot connect to X server"

PyBullet requires a display:

• Run on machine with monitor
• Use X11 forwarding: ssh -X user@host
• Virtual display: xvfb-run python simulation_host.py

Drone flies erratically

Reduce control gains in drone_controller.py:

Kp = 0.3
Kd = 0.2

Camera image not appearing

Ensure PIL/Pillow is installed:

pip install pillow