Control- Oriented Linear Fractional Transformation Modelling and H∞ Control of a Two-DOF Mass- Spring- Dashpot Dynamic System

摘要

This paper presents a systematic control-oriented uncertainty modelling approach in the Linear Fractional Transformation (LFT) framework of a Multi-lnput-Multi-Output (MIMO) mechanical system for designing an H∞ controller. A compact modelling structure has been formulated by considering the parametric uncertainties and disturbances to implement robust control law to achieve certain performance specifications. A popular mechanical system, namely, Two-Degree -of-Freedom (2DOF) Mass-Spring-Dashpot (MSD) dynamics system, which is highly oscillatory and implements in many classical control techniques have been considered as a candidate system to formulate proposed control-oriented LFT modelling framework and design FL controller to verify the effectiveness of the derived modelling structure in a real-time environment. This modelling methodology has been illustrated in the simulation environment and indicating satisfactory robust stability and performance margin of the designed H∞ controller. The proposed control strategy is compared with the standard Model Reference Adaptive Control (MRAC) law to express the effectiveness of the controller.