Abstract:By establishing kinematical model of ropeholding motion, knotwinding motion, ropebiting motion of the knotter, timing sequence and position relation of ropeholding, successful knotwinding and accurate ropebiting were described analytically. The effects of the timing sequence difference value φ between the motion of knotting hook and the motion of ropeholding plate and the angle α between the knotting hook axis and principal axis on ropeholding motion, knotwinding motion, ropebiting motion were analyzed. After the ropeloosening, function of ropeholding motion was analyzed. The mechanic condition of firm ropeholding before ropebiting, as well as the mechanic condition of allowing the rope to slip along axle direction of ropeholding plate and avoiding breaking the rope after ropebiting were established respectively. The results showed that the rope could be held firmly, wound successfully and bitten accurately when the value of α and φ are 90° and 24° respectively. The motion test of the physical prototype validated the theoretical model accuracy of ropeholding motion, knotwinding motion and ropebiting motion. The results of knotting test without bundling straws and with bundling wheat straws showed that the knottied rate of knotter may reach 100% and 99.25% respectively, which proved that the motion parameters of the knotter were matched reasonably.