Airbrake Plugin

An OpenRocket plugin adding airbrake behaviour in simulations.

At each simulation timestep, the plugin calculates airbrake extension given a Controller. Then, it calculates and overrides the simulation drag force given the current airbrake extension and dynamic pressure.

Setup

Requirements

JDK 17 is required.

Build

1. Clone this repo.
2. Download and place the OpenRocket v23.09 jar in the root directory. The jar must be named OpenRocket-23.09.jar.
3. Build the plugin jar to target/ using Gradle: ./gradlew jar or run jar task via IDE.

Usage

Option 1 (recommended): Use ./gradlew run (or use an IDE navigator) to automatically build the jar then run OpenRocket. (This option uses Java to run the OpenRocket jar in this folder.).

Option 2 (manual): Place the plugin jar in the OpenRocket plugins folder, most likely /home/user/.openrocket/Plugins or C:\Users\user\AppData\Roaming\OpenRocket\Plugins. Then open OpenRocket as usual.

OpenRocket must be restarted to load/reload the plugin.

Plugin Config in OpenRocket

Add the plugin to a simulation via New Simulation > Simulation Options > Add extension > Waterloo Rocketry > Airbrakes. The plugin will now be in effect during this simulation.

Always-Open Mode: Check the Enable Always-Open Mode box to disable PID control. Then, use Always-Open % to set the airbrake extension.

PID Control Mode: If Enable Always-Open Mode is not selected, the simulation will use PID control. Adjust PID constants with Kp, Ki, and Kd, and Target apogee.

Notes

• Airbrakes only take effect during the coast phase of simulations (between motor burnout and apogee), and only if velocity is greater than 23.5 m/s. This is due to the drag tabulation starting at 23.5 m/s.