Advised by Professor Kenji Shimada, Computational Engineering and Robotics Lab (CERLAB), Carnegie Mellon University, Sep 2020 ~ May 2022

"Error correction and disturbance compensation of end-effector poses of Rover Denso manipulator with Inverse Kinematic solver and PID controller". Master Thesis.

As the control group in the MobileManipulator team in CERLAB guided by Professor Kenji Shimada, we focus on the control of the manipulator and cooperate with other groups such as localization group and path planning group. We have worked on two robots, the Lord Weldmort robot and the Rover Denso robot, which both used the same Denso manipulator. The robots detects the ship parts on the field and welds along their edges. I have been building up more programming skills in Python and C++ and knowledge in ROS, Gazebo and RViz under the Linux environments.

In the Lord Weldemort robot simulation, I wrote Python and C++ programs to utilize a Realsense camera sensor to detect the 3 wall planes (front, left, right) and the gap point of the hole (on the right side of front plane). Then the program found the perpendicular of the edges, searched the gap point besides the hole, calculated the intersection points and drew points and planes in a 3D space overview. Finally, I performed a sample welding process, by revising and improving the existing Python and C++ code to tune the Denso 6-DOF manipulator speed and increase the sensing accuracy. 

On the Rover Denso robot, we documented and improved a more detailed tutorial for the setup and testing of the physical Rover Denso robot. Then I estimated possible noise and error of the welding path caused by the robot base movement in a 3D space by Jupyter Notebook. Next, I built up an algorithm that took the input of desired end-effector positions, converted each of them to a set of joint values with an inverse kinematics method (IKFast) in OpenRAVE, and moved the end-effector to track those desired positions and paths with error correction using PID methods. ROS Publishers and Subscribers nodes were built to communicate data between the main function and the IKFast algorithm for each iteration in the loop. The error correction and disturbance compensation of the end effector was refined by IKFast and a PID controller.