Meet Filip Zítek

He is a 3rd-year student of the bachelor study program “Theoretical Fundamentals of Mechanical Engineering” at the Faculty of Mechanical Engineering at CTU. He has been working on his internship in Testbed at CIIRC since August 2021.

“In Testbed at CIIRC CTU in Prague, I’m working on the 5-DoF Delta Robot. Standart Delta Robot consists of an upper stationary platform, three parallel arms, and a lower platform, which can move in any direction but cannot rotate due to its structure. Compared with serial industrial robots, the Delta robot has all the motors and gearboxes attached to the upper platform fixed to the frame, so only the lightweight lower platform and arms are moving. Because of these small-inertia moving parts, the movement can be very fast. On the other hand, the workspace of these robots is smaller than the workspace of serial robots. Therefore Delta robots are used for pick and place applications.”

“Our robot has two additional axes. Actuators on the stationary platform are connected via two telescopic Cardan shafts to the movable platform and worm gear, giving us the ability to rotate the end-effector in space.

My current task in this project is to generate trajectories for this robot. I’ve started with straight lines and arcs, then added the possibility to merge them after each other. The next step is to move through a set of predefined points in space. The difficulty with this task is that the generated trajectory has to be continuous and smooth. Both velocity and acceleration have to be continuous, so I am using a jerk-limited S curve profile for time-scaling the trajectory to achieve that. Also, I have been using our simulation model of the robot to check if the generated trajectory does not exceed any limit of the actuators at some point.

In the future, I would like to try some advanced time-scaling methods. For example, use the dynamical equations of the robot combined with the characteristics of the actuators to optimize the time-scaling. Another interesting task is to avoid certain speeds to minimize the vibrations of the robot.

During my internship, I’ve learned a lot of practical skills in robotics as well as new theoretical knowledge, which will be helpful in my further studies and work.”