Fa2004 16.33310-2 Note that the gain of the plant is negative(Kplant<0), so if kr < 0, then K= kplanthr >0, so must draw a 180 locus(neg feedback ateral autopilot: r to8 with k>0 Lateral autopilot: r to 8 with k<0 Figure 3: Lateral pole-zero map. Definitely need kr <0 Root locus with hr <0 looks pretty good as we have authority over the four poles kr=-1.6 results in a large increase in the dutch-roll damping and spiral/roll modes have combined into a damped oscillation Yaw damper looks great, but this implementation has a problem There are various flight modes that require a steady yaw rate (ssf). For example, steady turning flight Our current yaw damper would not allow this to happen -it would create the rudder inputs necessary to cancel out the motion Exact opposite of what we want to have happen, which is to damp out any oscillations about the steady turn� Fall 2004 16.333 10–2 • Note that the gain of the plant is negative (Kplant < 0), so if kr < 0, then K = Kplantkr > 0, so must draw a 180◦ locus (neg feedback) −2 −1.5 −1 −0.5 0 0.5 1 1.5 2 −2 −1.5 −1 −0.5 0 0.5 1 1.5 2 1 0.5 0.25 0.25 0.25 0.75 0.5 0.5 1 0.75 0.25 0.5 Lateral autopilot: r to δ r with k>0 Real Axis Imaginary Axis −3.5 −3 −2.5 −2 −1.5 −1 −0.5 0 −2 −1.5 −1 −0.5 0 0.5 1 1.5 2 1 0.25 0.5 0.25 0.5 0.75 0.25 0.5 0.75 Lateral autopilot: r to δ r with k<0 Real Axis Imaginary Axis Figure 3: Lateral pole­zero map. Definitely need kr < 0 • Root locus with kr < 0 looks pretty good as we have authority over the four poles. – kr = −1.6 results in a large increase in the Dutch­roll damping and spiral/roll modes have combined into a damped oscillation. • Yaw damper looks great, but this implementation has a problem. – There are various flight modes that require a steady yaw rate (rss = 0). For example, steady turning flight. – Our current yaw damper would not allow this to happen – it would create the rudder inputs necessary to cancel out the motion !! – Exact opposite of what we want to have happen, which is to damp out any oscillations about the steady turn