N. Jalili et N. Olgac, TIME-OPTIMAL SLIDING MODE CONTROL IMPLEMENTATION FOR ROBUST TRACKING OF UNCERTAIN FLEXIBLE STRUCTURES/, Mechatronics, 8(2), 1998, pp. 121-142
An improvement strategy in robust control is proposed for uncertain li
near or nonlinear systems. This two-stage control scheme first modifie
s the original desired trajectory, and then imposes robustness against
uncertainties in tracking the new trajectory. For the trajectory modi
fication stage, two different schemes are considered: Time Optimal-Rig
id Body Motion (TO) and Shaped Input (SI). The robustness stage is per
formed using Sliding Mode Control with Perturbation Estimation (SMCPE)
, an advanced form of SMC. This routine brings some strong features as
demonstrated by examples. A rotating hub with flexible beam attachmen
t is taken as the first example, and an undercontrolled two-mass syste
m with a linear spring as the second. The comparative studies show sup
erior results for the combination of TO-SMCPE over SI-SMCPE. Moreover,
this two-stage control exhibits stable and highly advantageous perfor
mance even for cases where H-proportional to type robust control struc
ture is declared unstable. (C) 1998 Elsevier Science Ltd. All rights r
eserved.