7-DOF Vehicle Dynamics Model: Implementation and Analysis

The 7-DOF vehicle dynamics model represents a classical modeling approach for analyzing overall vehicle motion characteristics. This model describes vehicle motion states through seven independent degrees of freedom, including: longitudinal motion, lateral motion, yaw motion, and the rotational motion of four individual wheels.

The longitudinal degree of freedom governs acceleration/deceleration movements; the lateral degree of freedom handles sideward movements during steering maneuvers; while the yaw degree of freedom characterizes the vehicle's rotation around its vertical axis. The independent rotational degrees of freedom for each wheel enable the model to accurately capture tire dynamics under various driving/braking conditions.

The model employs Newton-Euler equations to establish dynamic equations for each degree of freedom, utilizing the Magic Formula tire model to handle nonlinear tire forces. Special attention must be paid to load transfer effects between front and rear axles on tire vertical forces, as well as steering system geometry influences on front wheel angles.

This MATLAB implementation includes complete vehicle parameter configuration modules, differential equation solvers, and result visualization tools. Developed using earlier MATLAB versions, users should note potential compatibility considerations. The model outputs key dynamic parameters including vehicle trajectory, attitude angles, wheel speeds, making it suitable for vehicle stability analysis and control algorithm validation applications. The code structure features modular design with separate functions for force calculations, equation integration, and results plotting using MATLAB's ODE solvers and graphical libraries.