FUZZY BACKSTEPPING TORQUE CONTROL OF PASSIVE TORQUE SIMULATOR WITH ALGEBRAIC PARAMETERS ADAPTATION

Nasim Ullah – Shaoping Wang – Xingjian Wang

   This work presents fuzzy backstepping control techniques applied to the load simulator for good tracking performance in presence of extra torque, and nonlinear friction effects. Assuming that the parameters of the system are uncertain and bounded, Algebraic parameters adaptation algorithm is used to adopt the unknown parameters. The effect of transient fuzzy estimation error on parameters adaptation algorithm is analyzed and the fuzzy estimation error is further compensated using saturation function based adaptive control law working in parallel with the actual system to improve the transient performance of closed loop system. The saturation function based adaptive control term is large in the transient time and settles to an optimal lower value in the steady state for which the closed loop system remains stable. The simulation results verify the validity of the proposed control method applied to the complex aerodynamics passive load simulator.

Keywords: passive torque simulator, mathematical modelling, backstepping, fuzzy logic, algebraic parameters adaptation

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