Kinematics of Planar Quabody Mechanism with More Kinematics Bifurcation Positions

Abstract Based on multibody dynamics, some definitions of mechanism are defined. The kinematics bifurcation position is a cold researching spot for many many years. It is common in planar quabody mechanisms but has not been paid enough attention to. The kinematics bifurcation position refers to the mechanism position with a pressure angle of 90° of the follower, including the stuck position (dead point). In this paper, a planar quabody mechanism is studied. In a motion cycle, there are three kinematics bifurcation positions in the mechanism. The third derivative of angle to time, angular velocity, angular acceleration of the connecting rod in kinematics bifurcation positions is obtained by solving the kinematics parameters of kinematics bifurcation positions according to L’Hopital’s rule. If the driving body swings in sinusoidal law, the motion of the mechanism is continuous. The kinematics characteristics of the mechanism are independent of the simulation convergence and response bifurcation of nonlinear dynamics. The length of the rocker is 1 m, the length of the connecting rod is 0.5 m, the distance between the track of the slider and the fixed point of the rocker is 0.5 m, and the rocker swings according to the sine law with a period of 9 seconds. The computer simulation shows that the speed and acceleration are continuous and so there is no impact in the kinematics bifurcation positions.