关键词: 相轨迹；二自由度；三自由度；横向稳定性

Abstract: With the development of new chassis technologies, vehicle handling is becoming increasingly automated, making the boundary analysis and constraints of stability more crucial. This paper establishes dynamic equations based on nonlinear two-degree-of-freedom and three-degreeof-freedom vehicle models. It analyzes lateral stability using the phase planes of sideslip angle at the center of mass and yaw rate from each model, clarifies the advantages of nonlinear high-order models in stability analysis results, and provides a theoretical boundary for integrated chassis control.

Key words: phase trajectory; two-degree-of-freedom; three-degree-of-freedom; lateral stability