22-DOF Full-Coupled Vehicle Dynamics Modeling and Control Based on Modelica

Abstract

A 22-DOF vehicle dynamics model is developed in Modelica and implemented in MWorks Sysplorer 2025a. The generalized coordinates comprise six sprung-body motions, twelve translational motions of the four unsprung masses, and four wheel-spin motions. The physical plant is formulated as a coupled differential-algebraic equation system: the body, suspension, unsprung mass, wheel, tire, and road components are connected through custom acausal physical connectors, whereas steering and wheel-torque commands are retained only as external causal boundaries. The model is assessed using acceleration, braking, and steering-step datasets from MWorks, a 22-DOF Simulink model, and road tests. The threesource comparison demonstrates consistent overall dynamic trends and close agreement in key performance indicators, particularly in braking-distance prediction and steady steering response, thereby validating the effectiveness of the proposed acausal 22-DOF modeling framework.