Vehicle shimmy performance analysis using inerter-based suppression mechanism and considering steering linkage clearance

Vehicle shimmy could occur in the running process when the wheel encounters external disturbance, which affects the vehicle safety and stability. Four types of passive inerter-based suppression mechanisms are proposed to enhance the vehicle shimmy performance, the steering linkage clearance is considered as the nonlinear factor existing in the vehicle system. The vehicle shimmy model using inerter-based suppression mechanism and considering steering linkage clearance is established according to the Lagrange theory, the vehicle shimmy performance is studied based on the bifurcation analysis theory, the stable area and limit cycle oscillation (LCO) magnitude are acquired and compared for different suppression mechanisms. The effect of steering linkage clearance and structural parameters of the inerter-based suppression mechanisms on the vehicle shimmy performance is investigated. The results show that the inerter-based suppression mechanism can reduce the unstable area dominated by left and right steering shimmy significantly, shrink the vehicle shimmy occurred speed range and decrease the maximum LCO magnitude of the front wheel swing motion. When the steering linkage clearance exists and increases, the unstable area, vehicle shimmy occurred speed range and maximum LCO magnitude increase significantly, the vehicle motion can change from periodic to quasi-periodic or even chaotic, which degenerates the vehicle shimmy performance. Furthermore, larger inertance of the inerter and smaller stiffness of the auxiliary spring, larger contact stiffness and friction damping in the steering linkage clearance is better to suppress the vehicle shimmy. In addition, the inerter-based suppression mechanism can decrease the wheel swing angle around longitudinal axis and vertical dynamic tire load, which improves the suspension performance and further shows its advantage. Therefore, the inerter-based suppression mechanism can effectively suppress the vehicle shimmy and gives guiding significance for vehicle damping component design.