Proportional Integral (PI) Control of a Single Joint System for Robotic Application

Daniel Effiong Oku, Ibrahim Ahmed Tunde, Asiya Effiom Asiya

The aim of this work is to demonstrate how a Proportional Integral controller can be implemented in a systematic format by pole placement technique as against the conventional method of tuning a PI controller using Nichols Ziegler method and the controller is applied to test the dynamic response of a single joint system, consisting of a DC motor as the actuator and a coupled body that forms a single joint system with the motor acting as an actuator to cause rotation of the arm. The PI controller is designed and implemented on the system using pole placement technique. The results analysed shows that the controller is able to overcome steady state offset while maintaining the systems stability. In the time domain, a set-point of 1 radian was tracked at the output with a time constant of 0.775s and peak overshoot of 19%, while in the frequency analysis an infinite gain margin was realised and a phase margin of 81.5335o were both gotten from Bode and Nyquist plots respectively, The performance of the system was greatly improved by the implementation of the PI controller when compared to the open loop system whose step response was unstable with a gain margin of 0.1700 and a phase margin of 65.9822o respectively.