MECH466 - Lecture14-LeadLagCompensatorDesign-2009W

200809 mech466 automatic control 11 200809 mech466

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Unformatted text preview: 11 2008/09 MECH466 : Automatic Control 12 3 Comparison of step responses Compensated system Error constants Uncompensated system (C(s)=1) (C(s)=1) 1.4 1.2 Step-error constant Step- 1 3 Ramp-error constant Ramp- 0.6 Lead compensator gives • faster transient response (shorter rise and settling time) • improved stability 0.4 0.2 2008/09 Unit ramp input 4 0.8 0 0 5 1 2 3 4 MECH466 : Automatic Control 2 Ramp response 1 0 0 1 2 3 4 5 Lag compensator can be used to reduce steady-state error. steady- 5 13 Roles of lead & lag compensators 2008/09 MECH466 : Automatic Control Lead-lag compensator design Consider a system Consider Lead compensator Lead 14 C(s) C(s) G(s) G(s) Controller Improve transient response Improve Improve stability Improve Plant Analysis of CL system for C(s)=1 Analysis C(s)=1 Damping ratio ζ=0.5 Damping Undamped natural freq. ωn=2 rad/s Undamped Ramp-error constant Kv=2 RampKv=2 Lag compensator Lag Reduce steady state error Reduce Damping ratio ζ=0.5 Damping Undamped natural freq. ωn=4 rad/s Undamped Ramp-error constan...
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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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