Lekiwi Wheel Id Setup

Prerequisites

• Pi sees the controller board, e.g. /dev/ttyACM0 exists
• Only one wheel servo connected to the controller during each setup step
• LeRobot runtime imports work

Quick checks:

ls -l /dev/ttyACM* /dev/ttyUSB* 2>/dev/null || true
cd ~/projects/lerobot
.venv/bin/python - <<'PY'
from lerobot.robots.lekiwi.lekiwi import LeKiwi
from lerobot.robots.lekiwi.config_lekiwi import LeKiwiConfig
LeKiwi(LeKiwiConfig(port='/dev/ttyACM0', cameras={}))
print('LeKiwi import/construct OK')
PY

Step 1: set one wheel at a time

Disconnect all wheel servos from the bus. Then repeat this process for each wheel.

Left wheel -> ID 7

Connect only the left wheel servo, then run:

cd ~/projects/lerobot
.venv/bin/python - <<'PY'
from lerobot.robots.lekiwi.lekiwi import LeKiwi
from lerobot.robots.lekiwi.config_lekiwi import LeKiwiConfig
robot = LeKiwi(LeKiwiConfig(port='/dev/ttyACM0', cameras={}))
print('Setting up base_left_wheel -> target ID 7')
robot.bus.setup_motor('base_left_wheel')
print('DONE')
PY

Back wheel -> ID 8

Connect only the back wheel servo, then run:

cd ~/projects/lerobot
.venv/bin/python - <<'PY'
from lerobot.robots.lekiwi.lekiwi import LeKiwi
from lerobot.robots.lekiwi.config_lekiwi import LeKiwiConfig
robot = LeKiwi(LeKiwiConfig(port='/dev/ttyACM0', cameras={}))
print('Setting up base_back_wheel -> target ID 8')
robot.bus.setup_motor('base_back_wheel')
print('DONE')
PY

Right wheel -> ID 9

Connect only the right wheel servo, then run:

cd ~/projects/lerobot
.venv/bin/python - <<'PY'
from lerobot.robots.lekiwi.lekiwi import LeKiwi
from lerobot.robots.lekiwi.config_lekiwi import LeKiwiConfig
robot = LeKiwi(LeKiwiConfig(port='/dev/ttyACM0', cameras={}))
print('Setting up base_right_wheel -> target ID 9')
robot.bus.setup_motor('base_right_wheel')
print('DONE')
PY

Step 2: verify each isolated wheel after setup

After each individual setup, scan the port:

cd ~/projects/lerobot
.venv/bin/python - <<'PY'
from lerobot.motors.feetech.feetech import FeetechMotorsBus
print(FeetechMotorsBus.scan_port('/dev/ttyACM0'))
PY

Expected outputs while only one wheel is connected:

• left wheel: {1000000: [7]}
• back wheel: {1000000: [8]}
• right wheel: {1000000: [9]}

Step 3: verify all three together

After assigning all IDs, connect all three wheel servos and rescan:

cd ~/projects/lerobot
.venv/bin/python - <<'PY'
from lerobot.motors.feetech.feetech import FeetechMotorsBus
print(FeetechMotorsBus.scan_port('/dev/ttyACM0'))
PY

Expected result:

{1000000: [7, 8, 9]}

Order may vary, but the set should be 7/8/9.

Important warnings

• Only one wheel servo connected during each setup_motor() call.
• Do not run the stock full lerobot-setup-motors --robot.type=lekiwi flow on a chassis without the arm installed.
• Do not assume controller LED means the bus is healthy.
• If scan returns {} but /dev/ttyACM0 exists, USB-to-controller is alive but controller-to-servo bus is not.

Known weirdness

If you use the full LeKiwi object and later call disconnect while only a subset of motors exists, you may see errors like:

Failed to write 'Torque_Enable' on id_=1 ... There is no status packet!

That does not mean the wheel ID assignment failed. It happens because the LeKiwi bus object still contains the full expected motor map including missing arm motors. Ignore it in this wheel-only setup context.

Troubleshooting

/dev/ttyACM0 missing

• USB cable to Pi missing or bad
• wrong USB port/hub/cable
• controller board not enumerating

/dev/ttyACM0 exists but scan returns {}

• wheel servo not powered
• wheel servo not connected to the serial-bus side of the controller
• connector offset/flipped
• first-in-chain servo not actually on the bus
• servo dead

setup works for isolated wheels but all-three scan fails

• daisy-chain between wheels is wrong
• one servo in the chain is blocking downstream communication
• one wheel was assigned the wrong ID

Base-only verification after all three IDs are set

Do not use the full LeKiwi object for base-only verification on a chassis that does not have the arm yet. The full object expects IDs 1..9 and will complain about missing arm motors even when wheel setup is correct.

Instead, build a bus object containing only the wheel motors:

cd ~/projects/lerobot
.venv/bin/python - <<'PY'
from lerobot.motors import Motor, MotorNormMode
from lerobot.motors.feetech.feetech import FeetechMotorsBus
bus = FeetechMotorsBus(
    port='/dev/ttyACM0',
    motors={
        'base_left_wheel': Motor(7, 'sts3215', MotorNormMode.RANGE_M100_100),
        'base_back_wheel': Motor(8, 'sts3215', MotorNormMode.RANGE_M100_100),
        'base_right_wheel': Motor(9, 'sts3215', MotorNormMode.RANGE_M100_100),
    }
)

bus.connect(handshake=True)
print('CONNECTED_BASE_ONLY')
print('present velocity', bus.sync_read('Present_Velocity'))
PY

Expected result:

• connect succeeds
• Present_Velocity returns zeros or small near-zero values for all three wheels

Tiny base motion test

Once scan_port('/dev/ttyACM0') shows IDs 7,8,9 together, do a very small motion test with the robot on the floor, clear space around it, and hands away from the wheels.

Rotate in place for 1 second

cd ~/projects/lerobot
.venv/bin/python - <<'PY'
import time
from lerobot.robots.lekiwi.lekiwi import LeKiwi
from lerobot.robots.lekiwi.config_lekiwi import LeKiwiConfig
from lerobot.motors import Motor, MotorNormMode
from lerobot.motors.feetech.feetech import FeetechMotorsBus, OperatingMode

robot_model = LeKiwi(LeKiwiConfig(port='/dev/ttyACM0', cameras={}))
wheel_cmd = robot_model._body_to_wheel_raw(x=0.0, y=0.0, theta=45.0, max_raw=500)
print('wheel_cmd', wheel_cmd)

bus = FeetechMotorsBus(
    port='/dev/ttyACM0',
    motors={
        'base_left_wheel': Motor(7, 'sts3215', MotorNormMode.RANGE_M100_100),
        'base_back_wheel': Motor(8, 'sts3215', MotorNormMode.RANGE_M100_100),
        'base_right_wheel': Motor(9, 'sts3215', MotorNormMode.RANGE_M100_100),
    }
)