MECH466 - Lecture14-LeadLagCompensatorDesign-2009W

5 damping undamped natural freq n4 rads undamped ramp

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Unformatted text preview: t Kv=50 RampKv=50 Take into account all the above issues. Take MECH466 : Automatic Control Im Performance specification Performance Lead-lag compensator Lead- 2008/09 Desired pole 15 2008/09 MECH466 : Automatic Control Re 16 4 Comparison of step responses (after lead compensation) Compensated system Error constants (after lead compensation) Uncompensated system (C(s)=1) (C(s)=1) 1.4 1.2 Step-error constant Step- 5 Unit ramp input Unit 1 4 0.8 3 Ramp-error constant Ramp- 0.6 Lead compensator gives • faster transient response (shorter rise and settling time) • improved stability 0.4 0.2 0 0 2008/09 1 2 3 4 2 Ramp response 1 NOT SATISFACTORY! 0 0 1 2 3 4 5 Lag compensator can reduce steady-state error. steady- 5 MECH466 : Automatic Control 17 How to design lag compensator Lag compensator Lag We want to increase ramp-error constant We ramp- 2008/09 MECH466 : Automatic Control 18 Root locus with lag compensator Without compensator Without With compensator With s1 s1 Take, for example, z=10p. We do not want to change CL pole location s1 so We much (already satisfactory transient). 2008/09 MECH466 : Automatic...
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This document was uploaded on 03/05/2014 for the course MECH 466 at University of British Columbia.

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