Optometrist's Algortihm for Handovers

This work has been accepted for presentation at IEEE RO-MAN 2023. (Paper and video presentation wil be attached soon)

Optometrist's Algorithm

In this HRI project we have used the Optometrist's Algorithm, that allows users to personalize a Handover. Read more about the algorithm in my thesis: Personalization of Human-Robot Handovers using Evaluative Feedback

Handover Controlller for the Sawyer Robot Arm

This repository consists of a handover controller for the Sawyer robotic arm.

The robot picks up an object of fixed shape and hands it over to the collaborating human user. The handover uses Moveit! for trajectories and force sensing to detect the transfer, hence the user has to tug on the object before the gripper opens. The values of force thresholds are fixed for this particular object, and will have to be changed when using a different object.

In moveitcontroller you will find the code for just performing a single handover. Dynamic force thresholds are used, which are not 100% reliable. It is made more reliable in future versions that you will find on other branches. I hope to update the fixes here soon.

In personalization-stack and personalization-stack-experiment controller personalization for the experiment is added.

Gripper

Gripper used: ROBOTIS RH-P12-RN(A) - Documentation

DNYAMIXEL_SDK

$ git clone https://github.com/ROBOTIS-GIT/DynamixelSDK
$ cd DynamixelSDK/c++/build/linux64
$ sudo make install

Packet Loss Issue with this Gripper:

I faced an issue where the gripper would lose packets after a certain amount of use (it is probably just a local problem and might have a hardware fix) I temporarily fixed it with reading the data again, in case an incomplete packet is read. Since this was a HRI task, the delay if any did not matter at all.

In DynamixelSDK/ros/dynamixel_sdk/src/dynamixel_sdk/protocol2_packet_handler.py make the following changes:

def read4ByteTxRx(self, port, dxl_id, address):
        data, result, error = self.readTxRx(port, dxl_id, address, 4)
        while len(data)<4:
            data, result, error = self.readTxRx(port, dxl_id, address, 4)
        data_read = DXL_MAKEDWORD(DXL_MAKEWORD(data[0], data[1]),
                                  DXL_MAKEWORD(data[2], data[3])) if (result == COMM_SUCCESS) else 0
        return data_read, result, error

Download the ROS GUI for this gripper - ROS GUI Example from the ROBOTIS Manual ROS GUI will be useful to check the gripper motor parameters and to test it.