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andrea

Andrea Bajo

Sapienza, University of Rome
 

Visiting Scholar

Dept. of Mechanical Engineering
Columbia University

eMail: andrea.bajo@gmail.com

Current Projects:

  • Dynamics, parameter identification, and control for a dedicated open-architecture robot controller

I am a third year student at La Sapienza university, Rome, Italy. I came to ARMA as part of an internship related to my program of study.

My work at ARMA has been related to guided undergraduate reserach and study about dynamic modeling and control of robots. My four months (May 2007-August 2007) undergraduate project focused on modeling and simulating the so-called "yellow" robot, a six DoF industrial manipulator produced by Fanuc in 1988. The robot was disassebled to calculate the gear ratio and find information on the motors and to find mass and dynamic properties of the links. I wrote Matlab code for direct and inverse kinematics simulation, implemented the resolved rate algorithm based on the SR-Inverse of the Jacobian matrix and our own velocity law depending on the position and orientation error. The dynamics system of the Fanuc robot was modeled in Maple and simulated in Matlab. The dynamic was then updated with a load placed at the robot's gripper, gear ratio and joint's viscous friction. The system including the load was fundamental to test the performace of the PD controller using the computed torque method and the robust version.

fanu robot

(A)
(B)
(C)
 
(D)
(E)
Figure (A) shows the Fanuc robot. Figure (B) shows the Fanuc robot in a 3D simulation. Figure (C) shows the robot in a 3D simulation during the resolved rate algorithm. The robot moves from a given configuration to a desired one. During the simulation are shown the desired path, the current and the final orienation of the end effector. Figure (D) shows, in a 3D Matlab simulation, the sixth link updated with an external load: a ball. In the figure we can se how the center of mass changes. Figure (E) shows the circular spline of one of the harmonic drives. Pictures of all the gear were taken into account, with a graphic software the number of teeth and calculate the gear ratio.

Here are some movies representing some of the work I have done:

resoved rate

Resolved Rate simultaion

direct dynamics

Direct Dynamics Simulation (free falling with gravitation)

control simulations

Control simulations