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Hardware Setup

CAN Bus Setup

All I2RT arms and the Flow Base communicate over CAN bus at 1 Mbit/s. Each arm requires one USB-CAN adapter (CANable or compatible).

1. Bring up the CAN interface

# Check which CAN devices are detected
ls -l /sys/class/net/can*

# Bring up the interface at 1 Mbit/s
sudo ip link set can0 up type can bitrate 1000000

2. (Recommended) Auto-enable on boot

Install the provided udev rule so CAN interfaces come up automatically:

sudo sh devices/install_devices.sh

This installs a udev rule that runs ip link set ... up for every interface whose name starts with can*.

::: warning Persistent CAN IDs If you later assign persistent names (e.g. can_follower_l), you may need to update the udev rule to match. See Persistent CAN IDs. :::

3. Reset CAN devices

If a CAN device becomes unresponsive:

sh scripts/reset_all_can.sh

If you see RTNETLINK answers: Device or resource busy, unplug and replug the USB adapter.

Persistent CAN IDs

For multi-arm setups (e.g. YAM Cell with 4 arms), assign deterministic names to each adapter using udev rules based on the USB device's serial number or path.

::: tip CANable firmware Visit canable.io/updater to flash candlelight firmware if needed. YAM ships with candlelight pre-flashed. :::

Step 1 — Find sysfs paths

ls -l /sys/class/net/can*
# lrwxrwxrwx ... /sys/class/net/can0 -> ../../devices/.../can0
# lrwxrwxrwx ... /sys/class/net/can1 -> ../../devices/.../can1

Step 2 — Read the serial number

Plug adapters one at a time and note the serial for each:

udevadm info -a -p /sys/class/net/can0 | grep -i serial

Step 3 — Create udev rules

sudo vim /etc/udev/rules.d/90-can.rules

Add one line per adapter:

SUBSYSTEM=="net", ACTION=="add", ATTRS{serial}=="004E00275548501220373234", NAME="can_follower_l"
SUBSYSTEM=="net", ACTION=="add", ATTRS{serial}=="0031005F5548501220373234", NAME="can_follower_r"

::: warning Name length limit Interface names must start with can and be 13 characters or fewer. :::

Step 4 — Reload and verify

sudo udevadm control --reload-rules && sudo systemctl restart systemd-udevd && sudo udevadm trigger

Unplug and replug each adapter, then verify:

ip link show

You should see the named interfaces (can_follower_l, etc.) with state UP.

Recommended naming convention for YAM Cell:

Arm Interface name
Left follower can_follower_l
Right follower can_follower_r
Left leader can_leader_l
Right leader can_leader_r

Motor Configuration

Zero offsets

If the arm was disassembled or the motors replaced, you may need to re-zero them:

python i2rt/motor_config_tool/set_zero.py --channel can0 --motor_id 1

Run for each motor ID (1–6 for a standard YAM).

Safety timeout

The factory default is a 400 ms safety timeout: if no command is received within 400 ms, the motor enters damping mode. This prevents runaway behavior if the CAN connection drops.

Disable timeout (advanced users only):

python i2rt/motor_config_tool/set_timeout.py --channel can0
python i2rt/motor_config_tool/set_timeout.py --channel can0  # run twice

Re-enable timeout:

python i2rt/motor_config_tool/set_timeout.py --channel can0 --timeout

::: danger Safety note Disabling the timeout removes a key safety mechanism. Without it, a failed gravity-compensation loop can produce uncontrolled positive-feedback torque. Always set a PD target when operating without a timeout:

robot = get_yam_robot(channel="can0", zero_gravity_mode=False)

:::

Flow Base Hardware

Initial setup

  1. Install the battery and power on — the Raspberry Pi display lights up
  2. Verify the E-stop is not pressed (twist to release)
  3. Set the CAN selector switch to UP (uses on-board Pi)
  4. SSH in once the Pi has booted:
ssh i2rt@172.6.2.20   # wired Ethernet (static IP)
# Password: root

Firmware update

If the pre-installed software is outdated:

ssh i2rt@172.6.2.20
cd ~/i2rt && git pull

For Pi OS firmware, see the Pi SD Card Guide below.

Pi SD Card Backup & Restore

1. Find the SD card device

lsblk

2. Create image from SD card

sudo dd if=/dev/sdX of=pi_system.img bs=4M status=progress
sync

(replace /dev/sdX with your SD card device, e.g. /dev/sdc)

3. Flash image to a new SD card

sudo wipefs -a /dev/sdX
sudo dd if=pi_system.img of=/dev/sdX bs=4M status=progress
sync

4. Eject

eject /dev/sdX

5. Shrink image size (optional)

sudo ./pishrink.sh pi_system.img pi_system_shrunk.img

The latest pre-built Pi firmware image is available in the Flow Base firmware folder.

Connecting YAM to Flow Base

  1. Mount the YAM arm on the Flow Base top plate
  2. Route the CAN cable through the internal cable management
  3. Connect the arm CAN cable to the on-board CANable adapter
  4. Set the CAN selector switch to UP (Pi mode)
  5. SSH into the Pi and launch both arm and base controllers
ssh i2rt@172.6.2.20
python i2rt/flow_base/flow_base_controller.py &
python examples/minimum_gello/minimum_gello.py --gripper linear_4310 --mode follower --can-channel can0