embedded_ros_marvin

Key Project Structrure

├── embedded_ros_marvin/              # Source folder containing ROS 2 node implementations
│   ├── odrive_two_motors.py          # Subscribe to /joy_cmd_vel, control the odrives and publish /enc_vel
│   └── enc_odom_publisher.py         # Subscribe to /enc_vel and publish /odom
│   └── led_subscriber.py             # Subscribe to /is_auto and control safety light LED
│   └── pure_pursuit_lookahead.py     # Action server for follow_path, subscribe to /odom and publish /joy_cmd_vel
├── launch/                           
│   ├── launch_embedded.py            # Launches embedded nodes
│   └── launch_ekf.py                 # Launches the EKF node for sensor fusion
├── params/                           
│   └── arv_ekf.yaml                  # Parameters for the EKF node
├── sdr_estop/                        
│   ├── estopnew.grc                  # GNU radio flowgraph
│   └── estop.py                      # Auto generated python code from flowgraph
│   └── estop_epy_block_3.py          # Embedded python block for integer toggle

---

To run the robot for 2025 competition

1. Motor Calibration

• Make sure power switch is on and physical estop is unpressed
• Type odrivetool in a new terminal
• odrv0 and odrv1 should both be connected. If not, check USB connection and optionally restart computer.
• Type odrv0.axis0.requested_state = AXIS_STATE_FULL_CALIBRATION_SEQUENCE to calibrate odrv0
  • You should hear a beeping sound when calibration starts. If not, check if odrive indicator light is red. If yes, type odrv0.clear_errors()
  • During calibration, the light should flash green. When calibration completes, light will flash blue.
• Do the same for odrv1
  • When robot is on test stand, you can calibrate both odrives at the same time. When on the ground, calibrate one at a time.
• Exit odrivetool by typing quit()
• If odrive errors during runtime, enter odrivetool and type odrv0.clear_errors(), odrv1.clear_errors()
  • If error persists and odrive still flash red, double check if power is on and physical estop is unpressed

2. Launch Teleop

• Type ros2 launch embedded_ros_marvin launch_embedded.py use_enc_odom:=True
  • Make sure to quit odrivetool first
  • use_enc_odom:=True is optional and will publish encoder odometry
  • To reset encoder odometry to (0,0), rerun the launch command
• Odrive indicator lights should now flash green
• In a new terminal, type ros2 launch marvin_bot_description teleop_launch.py to start PS4 teleop

3. To start autonomous controller

• Type ros2 run embedded_ros_marvin pure_pursuit_lookahead
  • Make sure to first quit PS4 teleop and reset encoder odometry

4. To start remote estop

• Open estopnew.grc located in the sdr_estop folder
• Run the flowgraph

Notes

• Restarting the flowgraph will default estop value to 1 (no estop).

• If estop flowgraph is not ran, estop value will be default to 1 (no estop).

---

Launch Files

1. Launch Embedded Nodes

This launch file starts the odrive controller node. Make sure to first run motor calibration (but no need to set to closed loop control).

ros2 launch embedded_ros_marvin launch_embedded.py

Parameters:

• use_LED (default: true)

  • If false, the LED subscriber node will be disabled.

• use_enc_odom (default: false)

  • If true, an odom message will be published using encoder-based estimation, and the TF transform will be broadcast.
  • This should be set to false when using sensor fusion.

2. Launch EKF

This launch file starts the robot_localization EKF node

ros2 launch embedded_ros_marvin launch_ekf.py

• The EKF node uses parameters specified in: params/arv_ekf.yaml

---

Setup for indicator LED on a new device

1. Create a udev rule file

Run the following command to open the rule file:

sudo nano /etc/udev/rules.d/99-arduino.rules

2. Add the following rule

Copy and paste this line into the file:

SUBSYSTEM=="tty", ATTRS{idVendor}=="2341", ATTRS{idProduct}=="0042", ATTRS{serial}=="557363130383514121D2", SYMLINK+="LED_Arduino", MODE="0666"

3. Reboot the system

Notes

• To get the idVendor and idProduct, run:

  lsusb

• To get the serial number (optional), make sure the device is connected to ACM0, then run:

  udevadm info -a -n /dev/ttyACM0 | grep 'ATTRS{serial}'

---

Wireless access point password:

Password: 64182087