Identification of avian flapping motion from non-volant winged dinosaurs based on modal effective mass analysis
Fig 4
Forced vibrations of wings of Caudipteryx robot deduced by test rig (S1 Video) which approaches the flapping flight of modern birds [56].
Through curve iteration, we obtained the flapping function ϴright = 932.7sin(19.01t−3.35)+28.18sin(15.25t−5.103)+898.2 sin(19.16t+6.034) and ϴleft = 135.6 sin(6.453t+1.808)+1558 sin(0.4013t+6.198)+6.517 sin(18.87t + 0.4756). We here defined the anticlockwise motion of both wings as the positive direction. Therefore, the down stroke for the left wing is a positive motion while the down stroke for the right wing is a negative one.