Use of recursive and approximation methods in the dynamic analysis of spatial tracked vehicles.

摘要

In this investigation, the solution of the nonlinear dynamic equations of the spatial multibody tracked vehicle systems are obtained using different formulations and numerical procedures. The first technique is based on the augmented formulation that employs the absolute generalized coordinates and Lagrange multipliers. An iterative Newton-Raphson algorithm is used to solve the nonlinear constraint equations for the dependent variables. In the second approach, the recursive formulation which leads to a minimum set of strongly coupled equations, is employed. The third approach employed in this investigation is the velocity transformation where Newton Euler equations are used in order to avoid the singularity of the transformation matrices. Based on the classical Hertzian contact model, a contact force model is developed to describe the interaction between the tracked vehicle components. The contact between the rollers of the vehicle and the track links is examined using a theory based on the contact between curved and flat surfaces. A cylinder on a curved surface is used to develop the model of the contact force between the track link pin and the sprocket teeth. A model similar to the one used for the roller-track link contact is used for the analysis of the interaction between the track link shoe plates and the ground.; In this investigation, the tracked vehicle system is assumed to consist of three kinematically decoupled subsystems. The first subsystem consists of the chassis, the rollers, the sprockets and the idlers, while the second and third subsystems consist of the tracks which are represented as closed loop kinematic chains that consist of rigid links connected by revolute joints. In order to compare the performance of different formulations and the numerical procedures employed, a three dimensional tracked vehicle model that consists of one hundred and six rigid bodies and has one hundred and sixteen degrees of freedom is analyzed.