Real-time hybrid adaptive fuzzy control of a SCARA robot

Abstract

This paper presents the design, development and implementation of a Hybrid Adaptive Fuzzy Controller (HAFC) suitable for real-time industrial applications. The developed HAFC consists of a weighted combination of the Direct Adaptive Fuzzy Controller (DAFC) and Indirect Adaptive Fuzzy Controller (IAFC) and a gradually activated supervisory controller. The unique feature of the HAFC is that no mathematical models of the plant are required and the proposed controller is able to adaptively estimate the bound functions on-line, which are required for the determination of the supervisory controller. The supervisor controller in the sense that all signals are bounded guarantees global stability of the closed-loop system. The approach of rapid prototyping is employed to implement the HAFC so as to control a Selectively Compliance Assembly Robot Arm (SCARA) Robot in real time. Simulink, an interactive graphical software for simulating dynamic systems, is used to model, simulate and analyse the dynamic system. Once encouraging system performances are achieved, the HAFC is implemented in real-time through Real-Time Workshop (RTW). RTW generates C-codes from the Simulink block diagrams and in turn, the generated codes (object codes) are downloaded to the Texas Instruments TMS320C31 floating-point processor, together with the supporting files, for execution. The performance of the HAFC was found to be superior and it matches favourably the simulation results.