Connect 5v power to the hand (the dynamixels should light up during boot up.)
Connect the Micro USB cable to the hand (Do not use too many USB extensions)
Open Dynamixel Wizard and find the correct port using the options button and put that in main.py or ros_example.py. Note, you cannot have Dynamixel wizard open while using the hand's API, the port will be "busy" with the other process.
On Ubuntu you can find the hand by ID using /dev/serial/by-id The ID will stay persistent on reboots.
We offically support Python and ROS, but other languages are supported by Dynamixel SDK.
Functionality
Leap Node allows you to command joint angles in different scalings.
You can read position, velocity and current from the hand.
Do not query reads too often, going past 90hz for one set of angles or 30hz for all three will slow down the USB communication.
The default controller follows the PID control, up to the current limit cap.
Other controllers including velocity control or current control are supported as per the motor manual
For Lite, keep the current limit around 300ma.
For Full, you can raise the current limit up to 550ma.
If facing a jittery hand, adjust the PID values down.
If the hand is too weak, adjust the PID values up.
Troubleshooting
If your motor is 90/180/270 Degrees off, the horn is mounted incorrectly on the motor. Remount it.
If no motors show up, check that your serial port permissions are correct.
If some motors are missing, make sure they are IDed corrrectly and are connected to the U2D2.
If you get "overload error" and the motors are flashing red, then they have overloaded (self-collision etc). It should clear on a power cycle. If it happens often, lower the current limits in the control code so that it does not happen as often.
If you get "jittery" motors, try lowering the P and D values, either in the roslaunch file or the python file.
If you feel the motors are too inaccurate, you can also try raising the P and D values.
The CAD files are provided with a CC BY-NC-SA Attribution-NonCommercial-ShareAlike license which allows you to use and build upon our work non-commercially.
LEAP Hand is provided as-is and without warranty.
If you use LEAP Hand in an academic setting, please cite our paper:
@article{shaw2023leaphand,
title={LEAP Hand: Low-Cost, Efficient, and Anthropomorphic Hand for Robot Learning},
author={Shaw, Kenneth and Agarwal, Ananye and Pathak, Deepak},
journal={Robotics: Science and Systems (RSS)},
year={2023}
}
