iIi I J Aii * 0 4 ?n nn no nn U M c n aMi n 1 il 0. ni tnutif llIf ii I I'IU mII TIME (SECONDS) (a) Design based on nonlinear servomechanism theory (b) Design based on linear servomechanism theory Figure 4-1. Tracking error: reference = 2sin(t), no disturbance .0 UI UW NI V .l I i. VV g L o u U W &It,.• .P l,,w AL