基于空间激扰的跨座式单轨车辆转向架Hopf分岔特性分析OA

To investigate the stability of the bogie in a straddle-type monorail vehicle,the Hopf bifurcation characteristics of the straddle-type monorail vehicle bogie system were analyzed based on the spatial perturbations of the mechanical properties under the wheel-rail contact relationship.Firstly,a three-degree-of-freedom nonlinear dynamic model of the vehicle bogie,incorporating spatial perturbations,was established.Secondly,the Hurwitz stability criterion was employed to solve for the critical speed of the bogie system,and the type of Hopf bifurcation was identified via the center manifold stability index.The theoretical results were further validated numerically using the MATCONT toolbox.Finally,the influence of different spatial perturbation conditions on the stability of the bogie system was discussed.The research results show that at a motion state of low speeds,the bogie primarily exhibits rolling motion with a frequency of 2.4 Hz;at a motion state of medium and high speeds,the motion is dominated by coupled yawing and rolling,with frequencies ranging from 1.3 Hz to 2.4 Hz.When the speed reaches 163.563 24 km/h,the system undergoes a supercritical Hopf bifurcation,resulting in the emergence of a stable limit cycle;at a speed of 163.563 60 km/h,a saddle-node bifurcation occurs,leading to an unstable limit cycle.Under spatial perturbations,the critical speed of the bogie decreases with increasing radial stiffness of the guiding wheel and radial damping of the stabilizing wheel but increases with greater radial damping of the guiding wheel,radial stiffness of the stabilizing wheel,as well as the radial stiffness and damping of the running wheel.Moreover,changes in the structural parameters of the bogie can induce transitions between supercritical and subcritical Hopf bifurcations.To avoid subcritical Hopf bifurcations that may cause abrupt changes in the system's motion state,the structural parameters of the bogie should be carefully designed.