Koch v1.1

In the steps below, we explain how to assemble the Koch v1.1 robot.

Order and assemble the parts

Follow the sourcing and assembling instructions provided in this README. This will guide you through setting up both the follower and leader arms, as shown in the image below.

For a visual walkthrough of the assembly process, you can refer to this video tutorial.

Install LeRobot 🤗

To install LeRobot follow, our Installation Guide

In addition to these instructions, you need to install the Dynamixel SDK:

pip install -e ".[dynamixel]"

Configure the motors

1. Find the USB ports associated with each arm

To find the port for each bus servo adapter, run this script:

python lerobot/find_port.py

Finding all available ports for the MotorBus.
['/dev/tty.usbmodem575E0032081', '/dev/tty.usbmodem575E0031751']
Remove the USB cable from your MotorsBus and press Enter when done.

[...Disconnect corresponding leader or follower arm and press Enter...]

The port of this MotorsBus is /dev/tty.usbmodem575E0032081
Reconnect the USB cable.

2. Set the motors ids and baudrates

Each motor is identified by a unique id on the bus. When brand new, motors usually come with a default id of 1. For the communication to work properly between the motors and the controller, we first need to set a unique, different id to each motor. Additionally, the speed at which data is transmitted on the bus is determined by the baudrate. In order to talk to each other, the controller and all the motors need to be configured with the same baudrate.

To that end, we first need to connect to each motor individually with the controller in order to set these. Since we will write these parameters in the non-volatile section of the motors’ internal memory (EEPROM), we’ll only need to do this once.

If you are repurposing motors from another robot, you will probably also need to perform this step, as the ids and baudrate likely won’t match.

Follower

Connect the usb cable from your computer and the 5V power supply to the follower arm’s controller board. Then, run the following command or run the API example with the port you got from the previous step. You’ll also need to give your leader arm a name with the id parameter.

For a visual reference on how to set the motor ids please refer to this video where we follow the process for the SO101 arm.

python -m lerobot.setup_motors \
    --robot.type=koch_follower \
    --robot.port=/dev/tty.usbmodem575E0031751 # <- paste here the port found at previous step

You should see the following instruction.

Connect the controller board to the 'gripper' motor only and press enter.

As instructed, plug the gripper’s motor. Make sure it’s the only motor connected to the board, and that the motor itself is not yet daisy-chained to any other motor. As you press [Enter], the script will automatically set the id and baudrate for that motor.

You should then see the following message:

'gripper' motor id set to 6

Followed by the next instruction:

Connect the controller board to the 'wrist_roll' motor only and press enter.

You can disconnect the 3-pin cable from the controller board but you can leave it connected to the gripper motor on the other end as it will already be in the right place. Now, plug in another 3-pin cable to the wrist roll motor and connect it to the controller board. As with the previous motor, make sure it is the only motor connected to the board and that the motor itself isn’t connected to any other one.

Repeat the operation for each motor as instructed.

When you are done, the script will simply finish, at which point the motors are ready to be used. You can now plug the 3-pin cable from each motor to the next one, and the cable from the first motor (the ‘shoulder pan’ with id=1) to the controller board, which can now be attached to the base of the arm.

Leader

Do the same steps for the leader arm but modify the command or script accordingly.

python -m lerobot.setup_motors \
    --teleop.type=koch_leader \
    --teleop.port=/dev/tty.usbmodem575E0031751 \  # <- paste here the port found at previous step

Calibrate

Next, you’ll need to calibrate your robot to ensure that the leader and follower arms have the same position values when they are in the same physical position. The calibration process is very important because it allows a neural network trained on one robot to work on another.

Follower

Run the following command or API example to calibrate the follower arm:

python -m lerobot.calibrate \
    --robot.type=koch_follower \
    --robot.port=/dev/tty.usbmodem58760431551 \ # <- The port of your robot
    --robot.id=my_awesome_follower_arm  # <- Give the robot a unique name

We unified the calibration method for most robots. Thus, the calibration steps for this Koch arm are the same as the steps for the SO100 and SO101. First, we have to move the robot to the position where each joint is in the middle of its range, then we press Enter. Secondly, we move all joints through their full range of motion. A video of this same process for the SO101 as reference can be found here.

Leader

Do the same steps to calibrate the leader arm, run the following command or API example:

python -m lerobot.calibrate \
    --teleop.type=koch_leader \
    --teleop.port=/dev/tty.usbmodem58760431551 \ # <- The port of your robot
    --teleop.id=my_awesome_leader_arm  # <- Give the robot a unique name

Congrats 🎉, your robot is all set to learn a task on its own. Start training it by following this tutorial: Getting started with real-world robots