Design of MIMO fractional order fault tolerant control based on intelligent QFT controller of robotic manipulator

Control systems that ensure safety, reliability and maintainability are challenging tasks to remedy the problems caused by unexpected faults. The quantitative-feedback-theory is efficient control method used for MIMO-systems with parametric uncertainties. Besides, the robust fractional-PID controller and fractional pre-filter demonstrated their efficiency to ensure robust control and performance specifications. The novelty consists of associating the benefits of fractional control and the QFT approach to develop a fractional-tolerant-controller for MIMO systems. A fractional fault-tolerant controller (FFTC) with some special characteristics allowing to overcome the design complexity and control effort increase due to simultaneous presence of disturbance with jumping faults is developed. Additionally, high-tracking performance is taken into consideration. The proposed approach is designing a controller with structure that converts the faults and the interaction in MIMO system to standard QFT disturbance rejection problem and guarantees high performance thanks to fractional approach. The proposed approach is applied to SCARA robot manipulator.