- docker-full: a ROS2 Humble dockerfile for use on an RPi4
- spot_ws: a ROS2 workspace containing all custom packages to control a Spot Micro
Originally designed based off of the Spot Micro NovaSM3. The electronics have mostly been replaced with just an RPi4.
You'll want to put together your robot, including servos, before doing anything with this repo. Instead of NovaSM3 electronics, we just use an RPi4 (8GB RAM, 32GB SD) and a PCA9685 breakout board to control the servos.
For commanding the robot, a Logitech F710 gamepad is used.
Make sure to use an updated version of Raspberry Pi OS. If you use the Image Downloader, be sure to enable ssh and turn on wifi. You will also want to use raspi-config to enable I2C after your first boot.
For the ROS2 Camera node, we use ros2-v4l2-camera. That doesn't work with the current libcamera drivers available with Raspberry Pi OS. Follow the instructions on the ros2-v4l2-camera node README to use an older driver.
Some of this software is based on the spot-mini-mini repo from OpenQuadruped.
You can install FoxGlove and use the foxglove-bridge node to view camera data from the robot. There's a bit of lag, but it works well.
After you install FoxGlove, start the robot (using a launchfile that includes foxglove-bridge) and then connect FoxGlove to the IP address of the RPi. You should be able to see camera data immediately.
NOTE: There are a lot of parameters you may want to tweak for your robot. The most important are probably servo pin numbers, which are hardcoded in spot_ws/src/joint_ctl/joint_ctl/servo_ctl.py
- Set up the RPi 4, install docker on it, build the docker image from
docker-full - start the docker container and get a shell on it (see instructions in
docker-fullREADME) - within docker, run the following
cd /home/ros/spot_ws
source /opt/ros/humble/setup.bash
colcon build
source install/setup.bash
Check out the launch files in spot_ws/launch for examples of what you can do.
Run unit tests and view results with something like
colcon test --packages-select motion_control
colcon test-result --all --verbose
You can run tests on only a single package (change the name to whatever you want). You can also run tests on all packages.
For the robot as a whole:
- +X is forward
- +Y is up-down
- +Z is right (CHECK THIS?)
Most mammals that we interact with have ball joints for hips. The Spot Micro instead has two hinges that collectively serve the same purpose. These two hinges are pretty close to each other, but the small linear distance between them does introduce another transform into the robot kinematics. In order to distinguish between joints, we call the joint closest to the body the "coxa" and the joint second from the body the "hip".
| Joint Term | Description |
|---|---|
| coxa | First joint between body and a leg. |
| hip | Second joint in leg, between coxa and knee. |
| knee | Final joint in leg. Backwards from how a human knee would bend. |
| foot | The end of the lowest rigid link in the leg. |
Leg links similarly have specific naming:
| Leg link | Description | | pelvis | The short link between coxa and hip joints. | | thigh | The upper leg link, between hip and knee. | | shin | The lower leg link, between knee and ground. |
In order to identify specific joints in the robot, we sometimes used TLAs. For example, the front-left coxa would be called the "flc" and so forth.
- recalibrate FR
- ikine doesn't seem to handle leg extensions well
- get walking working with direction (backwards, angled, turn)
- document frames of reference
- leg frame
- estop into servo controller?
- rigid-halt or go limp?
- make sure nodes/processes finish cleanly on ctl-c
- electronics diagrams