MECH 466 - Lecture22-DesignExamples-2009W

4 design of lead lag compensators design lead 94 lead

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Unformatted text preview: oot Frequency response Frequency Lead-lag compensated Lead- 9.2 0.2 0 0 0.5 1 1.5 2008/09 2 2.5 9 9.5 3 9.6 9.7 9.8 9.9 MECH466 : Automatic Control 10 21 Open-loop frequency response 2008/09 MECH466 : Automatic Control 22 Gain, PM, and step response Change preamplifier gain K to 20, 40, 60. Change Step responses 0 1.4 GM=68.41dB -50 1.2 -100 10 1 -2 10 -1 10 0 10 1 10 2 0.8 K=40 (PM=53) PM=88.68deg -150 0.4 K=60 (PM=45) -200 0.2 -250 10 2008/09 K=20 (PM=67) 0.6 -100 -2 10 -1 10 0 MECH466 : Automatic Control 10 1 10 0 0 2 23 2008/09 2 4 6 MECH466 : Automatic Control 8 24 6 Lead-lag design via freq. response Design specifications (same as before) Design Gain+lead compensation 100 25% overshoot 25% 2% settling time 2 seconds 2% Kv=20 Kv=20 Open-loop Bode plot Open2 KG(s) (PM=13) KG(s) 0 -200 -2 10 1. Use the gain to satisfy Kv. Kv. KCLead(s)G(s) (PM=50) (s)G(s) 1 .5 G(s) G(s) -100 One possible procedure One -50 2. Use lead compensator to increase PM (and gain -1 10 MECH466 : Automatic Control 2 25 -1 10 -200 -2 10 -1 10 0 10 1 10 1 -100 0.5 2008/09 -1 10 0 10 1 10 2 10 0 0 1 2 3 4 MECH466 : Automatic Control 5 26 Advantages Advantages Large capacity with low cost Large Fast access speed Fast -200 -250 -2 10 0 0 Computer Computer Mobile audio player Mobile Mobile phone Mobile Video camera Video Car navigation, etc. Car -50 -150 2 10 Data storage media Data Applications Applications 2 10 1 10 Hard disk drives KCLead(s)CLag(s)G(s) (s)G(s) (PM=69) 1.5 G(s) G(s) 0 10 2008/09 KG(s) (PM=13) KG(s) -100 1 -200 Step responses 0 2 10 0 .5 Gain+lead/lag compensation Open-loop Bode plot Open- 1 10 -150 -250 -2 10 2008/09 0 10 -100 crossover frequency). 3. Use lag compensator to decrease gain crossover frequency (to increase PM). 100 Step responses 1 MECH466 : Automatic Control 2 3 4 5 27 2008/09 Samsung HG501LJ MECH466 : Automatic Control 28 7 Control mechanism Modeling & Block diagram Spindle Disk spins ~5,400rpm Disk Head slider flies over Head VCM the disk <100nm height Input: VCM actuator Input: Output: Head position Output: Tracks Track seeking: Head Track moves from one track to another. Head Arm Track following: Head Track Pivot follows a specified track. Samsung HG501LJ VCM Arm Flexure Head R(s): R(s): Desired head position D(s): Torque disturbance D(s): MECH466 : Automatic Control 29 Transfer functions Load G2(s) Y(s): Y(s):...
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This document was uploaded on 03/05/2014 for the course MECH 466 at UBC.

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