Server Example: Granular Media

Overview

Stands a PD-controlled ANYmal on a native granular bed created with World::addGranularParticles (raisim::GranularSystem). The grains are streamed to the viewer as instanced sphere visuals. See Granular Media.

Target

CMake target: granular_media. The source is examples/src/benchmark/granular_media.cpp.

Run

Run the build-tree executable:

./build-examples/examples/granular_media

On Windows, run granular_media.exe instead. This example uses RaisimServer. Start rayrai_tcp_viewer and connect to port 8080. Without --steps, the simulation starts once a viewer connects and runs until you stop it.

Options

• --steps N runs a fixed number of steps without waiting for a viewer, then prints the time per step and averaged contact statistics. The exit code is 2 if the bed became unstable (non-finite positions or grains faster than --max-allowed-speed).
• --port=N changes the server port.
• --resolution, --layers, --radius, --spacing, --bed-length, and --bed-width set the bed geometry; --substeps, --stiffness, --damping, --tangential-stiffness, --tangential-damping, --friction, --rolling-friction, and --hertz set the granular contact model.
• --settle-steps and --robot-settle-steps set how many steps run before the server starts, to let the bed and then the robot settle.