Experimental Comparison of Model-Free Nonlinear Controllers on a 4-Degrees-Of-Freedom SCARA Robot

This paper presents the construction of an experimental platform consisting of a 4-degrees-of-freedom SCARA robot. The proposed platform is designed to quickly test nonlinear controllers experimentally. The code is written in C++, which is both flexible and efficient, resulting in a 2 ms sample time for the closed-loop controller. Additionally, a model-free adaptive controller is proposed in this work, which uses the direct kinematics of the robot to construct a pseudo-regressor. The proposed approach demonstrated superior performance when compared experimentally with two other model-free controllers and a classical modelbased adaptive controller.