Affiliations: Instrumentation and Control Engineering Division, Netaji Subhas Institute of Technology, University of Delhi, New Delhi, India
Correspondence:
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Corresponding author. Vijay Mohan, Instrumentation and Control Engineering Division, Netaji Subhas Institute of Technology, University of Delhi, New Delhi 110078, India. Tel.: +91 9968790714; Fax: +91 1125099022; E-mail: vijay13787@gmail.com.
Abstract: A novel Non-Linear Fractional order PID controller (NLF-PID) is designed for control of coupled and non-linear 2-link rigid robot. The structure of proposed controller comprises of non-linear hyperbolic function of instantaneous error and current state cascaded with Fractional Order PID (FO-PID). Non-linear function provides adaptive control ability while incorporation of fractional operator enhances flexibility of designed controller. To examine the comparative merits of NLF-PID controller, Non-linear PID (NL-PID), FO-PID and traditional PID schemes are also implemented. Design variables of controllers are optimally tuned using multi objective Non-dominated Sorting Genetic Algorithm II (NSGA-II) for small variation in control and error signal. Results prove that NLF-PID provides robust and efficient control of robotic arm as compared to other designed controllers for reference tracking, model uncertainty, disturbance and noise due to inherent shortcoming of sensor.
Keywords: Fractional order PID (FO-PID), non-linear PID (NL-PID), non-linear fractional order PID (NLF-PID), robustness analysis, NSGA-II
