Assembe_tutorial.md

Placement of Servos

There are 8 servos, including 2 * ST-3250 (50kg.cm) servos and 6 * ST-3215 (30kg.cm) servos, and the placement of servos can be found below:

Placement of Links

There are 10 links and the placement for different links can be found below:

USB board connection

Connect the power supply and servos by referring image blow.

Note: The V1 port is labeled as DC6V-9V, but I checked with Feetech tech support and confirmed that a 12V power supply can be safely connected

Configure Servos using LeRobot

A. Install LeRobot library and Find USB port

Refer the Install LeRobot section of offical LeRobot tutorial

You should also find the USB port by following instructions of Find the USB ports associated to each arm in LeRobot tutorial

Note: The port number of the Feetech USB board may occasionally change. If you encounter a "port not found" error after identifying the port earlier, please recheck the USB port.

B. Configure the servos using LeRobot

Below script demos how to configure servo. The configuration script will do 2 things:

1. Set the servo's id as 1
2. Set the position of the servo to 2048

python lerobot/scripts/configure_motor.py \
  --port /dev/tty.usbmodem58760432961 \
  --brand feetech \
  --model sts3215 \
  --baudrate 1000000 \
  --ID 1

Then unplug your servo and plug the second servo (it should be a ST3250 servo) and set its ID to 2. Here you can keep using the --model sts3215 since both model types shares the same SDK and control table.

python lerobot/scripts/configure_motor.py \
  --port /dev/tty.usbmodem58760432961 \
  --brand feetech \
  --model sts3215 \
  --baudrate 1000000 \
  --ID 2

Redo the process for all your motors until ID 8. Please note that the IDs for 2 ST-3250 servos should be 2 and 3. You can also see servo placement drawing above for reference.

C. Add motor horn to all 8 servos

You can refer to LeRobot official video for adding the motor horn to all 8 servos. The video can be found here Add Motor Horn to servos

Assemble of PingTi Aarm

Assemble of Base

See SO-100 assemble video for the assembly of base links with servo (ID 1). Specifically, you should look at the Step4.1 to Step4.4 in this video

Assemble of Shoulder

Connecting wires to servos The shoulder joint consists of 2 ST-3250 servos and you should connect all 4 wires before putting the servos into slots, see image below.

Putting servos into slots of base_yaw_link Put the ID 2 servo on the left slot and ID 3 servo on the right slot. Secure the servo with four M2x5 screws. See image below

Attaching shoulder link to servo horns Use 8 M3x6 machine screws to attach shoulder link to servo horns. Pls note the shoulder link should be vertically attached to the servo horns and servo horns on its end should face forward. See image below.

Assemble of Elbow

Connecting wires to servos The elbow joint consits of 2 ST-3215 servos with ID 4 and ID 5. You should connect wires properly before putting servos into slot. See image below

Putting servos into slots and attache elbow link Put the ID4 and ID5 into servo slots like image below and secure the servos using four M2x5 screws. Also attach the elbow link to servo horns using 8 M3x6 machine screws.

Assemble of Wrist and Gripper

See SO-100 assemble video for the assembly of wrist links, gripper links and servos (you would use servos with id 6, 7 and 8).

Specifically, you should start from Step 4.9 to Step 4.12 in this video

Assemble of SO-100 Leader Arm

See the SO-100 assemble video for Leader Arm