Project description

Robotic arm

General Description

I did my bachelor's thesis while working for the department of automation science and engineering of the Tampere University of Technology. While a bachelor's thesis can just be a literary review, I wanted to create some device and write about it. I had also always wanted to make a robotic arm from scratch, so it was a good thesis subject.

The robotic arm will be used for researching machines in human environment, and also for exercises in some automation courses. The thesis is written about how additive manufacturing technologies can be used to build mechanical assemblies. For instance, I recommend a minimum modulus of 1.5 for FDM manufactured gears.

The robotic arm has four degrees of freedom. It is built entirely by me, I designed the mechanics and built them, then designed and built the electronics and finally made the programs that run on the robot's ARM Cortex M4 based controller and PC. The robot controller is programmed with C++ and the PC GUI is programmed using Processing, which is based on Java. The robot has a cascade PID scheme controlling both joint velocities and joint positions to achieve good motion and position accuracy. The GUI can be used to fully control the robotic arm, create paths and run sequential jobs.



Robotic arm

Purpose: Bachelor's thesis
Start Date: June 2015
Finish Date: August 2015
URL: https://github.com/jkoljo

  • Designed in SolidWorks
  • Calculated in Matlab
  • Runs C++ on robot controller
  • Cascade PID controlled
  • Accurate encoder feedback

Current status

The robotic arm is finished and it works as intended. It can repeatedly achieve positions within 1 cubic centimeter in it's entire working area. The thesis project got the best grade of 5. The robotic arm is installed on top of a Kobuki mobile robotics research base at the time of writing this description. Kobuki base gives the robotic arm instructions via ROS node and a serial protocol I defined.