Curving Performance of Straddle-Type Monorail Vehicle with Single-Axle Bogies Based on Spatial Multi-Body Dynamic Analysis

Straddle-type monorail ,as a unique technology, energy saving and environmental protection, is different from the subway of urban rail transit system. In order to study the curving performance of a new type of the straddle-type monorail vehicle with single-axle bogies ,the three-dimensional spatial dynamics model which consists of the vehicle model and track model designis proposed by the multi-body dynamics soft ADAMS. The monorail vehicle dynamic model which consists of three types of tire -track contact model and the nonlinear model of the horizontal stop is established. Based on the dynamic model, the influences such as pre pressure and curve super-high rate parameters of the curve passing for the dynamic characteristics are discussed. The simulation results show that the suitable preload for the guide and stabilizer tires of straddle-type vehicle with single-axle bogies is 5KN and after selecting the appropriate pre-pressure, the super-high rate is recommended to be 8%-10%.

Yaw compensation and yaw relaxation controls for active steering of railway wheelsets via electromechanical actuators

It is known that good curving performance and stability often have conflicting requirements given a passive yaw stiffness of the wheelset. Using an active steering system, however, has the potential to realize improved curving performance with a satisfactory running stability. Relatively simple active control solutions of yaw relaxation and yaw compensation are illustrated and compared in this paper. In both control solutions, only low-cost electromechanical actuators and load cells are adopted for low-frequency actuations. Associated with a prototype of the two-axle vehicle, the dynamic performances of yaw relaxation and yaw compensation controls for different yaw stiffness configurations are simulated. The homogenous simulation results demonstrate excellent dynamic performance in curve negotiation and stability with the active steering strategies adopted.

Effect of mass distribution on curving performance for a loaded wagon

The location of wagon gravity center for a loaded wagon is underestimated in a vehicle–track coupled system. The asymmetric wheel load distribution due to loading offset significantly affects the wheel-rail contact state and seriously deteriorates the curving performance in conjunction with the height of gravity center and cant deficiency. Optimizing the location of gravity center and cruising velocity, therefore, is of interest to prevent the derailment and promote the transport capacity of railway wagons. This study aims to reveal the three-dimensional influencing mechanism of mass distribution on vehicle curving performance under different velocities. The wheel unloading ratio is regarded as the evaluation index. A simplified quasi-static model is established considering essential assumptions to highlight the influence of lateral and vertical offset on curving performance. For a more accurate description, the MBS models with various locations of wagon gravity center are built and then negotiate curves in different simulation cases. The simulation results reveal that the distribution of wheel unloading ratio determined by loading offset is like contour lines of ‘basin’. Based on the conclusions of quasi-static analysis and dynamics simulations, the regression equation is proposed and the fitting parameters are calculated for each simulation case. This paper demonstrates the necessity of optimizing the location of wagon gravity center according to the running condition and offers a novel strategy to load and transport the cargo by railway wagons.