Quadruped.md

Quadruped rover

The controller for this model is the result of Ashvath's project GSoC 2020: Walking Robot Support For Ardupilot.

Usage

Gazebo and the plugins should be installed as per the ArduPilot Gazebo Plugin instructions.

Update the GZ_SIM_RESOURCE_PATH to include these models:

export GZ_SIM_RESOURCE_PATH=$GZ_SIM_RESOURCE_PATH:\
$HOME/SITL_Models/Gazebo/models:\
$HOME/SITL_Models/Gazebo/worlds

Run Gazebo

gz sim -v4 -r quadruped_runway.sdf

Run ArduPilot SITL

This model requires a custom controller which is implemented in the ArduPilot Lua script quadruped.lua. There is a copy of this script in SITL_Models/Gazebo/config/scripts for convenience.

Set up the rover and SITL following the ArduPilot wiki instructions for Walking Robots.

Copy the Lua script quadruped.lua to the scripts folder for SITL (this is usually $ARDUPILOT_HOME/scripts).

The parameters set SCR_ENABLE = 1 and you will need to reboot the autopilot after the initial start to retrieve the full set of scripting parameters. You may also need to increase the SCR_HEAP_SIZE.

sim_vehicle.py -v Rover --model JSON --add-param-file=$HOME/SITL_Models/Gazebo/config/quadruped.param --console --map

Controls

Manual control in MAVLink:

# stand up from rest position
MANUAL> arm throttle
# rotate counter clockwise
MANUAL> rc 1 1000
# rotate clockwise
MANUAL> rc 1 1000
# lean right
MANUAL> rc 2 1000
# lean left
MANUAL> rc 2 2000
# walk backward
MANUAL> rc 3 1000
# walk forward
MANUAL> rc 3 2000
# lean forward
MANUAL> rc 4 1000
# lean backwards
MANUAL> rc 4 2000
# return to rest position
MANUAL> disarm

Dimensions

• height: 53.23 mm
• coxa_axis_width: 101.42 mm
• coxa_axis_length: 177.03 mm
• coxa_axis_to_femur_axis: 30.0 mm
• femur_axis_to_tibia_axis: 76.17 mm
• tibia_axis_to_foot: 122.0 mm

Credits

Hexapod CAD model

• Author: Tim Mills
• Model: Hexapod Robot