Abstract: Freeway is a strong coupled nonlinear system with many uncertainties.It is easily influenced by many disturbances.It is proposed that using backstepping variable structure control method to design the laws of velocity.Its purpose is to assure traffic density keeping near the desired density.The result of simulation shows that the control laws have the good robustity.

Key words: automated highway systems, traffic density control, backstepping variable structure control

摘要： 高速公路交通是一个强耦合的非线性系统，极易受到各种干扰因素的影响。针对高速公路交通流模型的不确定性，提出用反演变结构控制理论，设计速度的控制律，使得高速公路主线交通流密度保持在期望密度的小邻域内，仿真结果表明所得的控制律具有很好的鲁棒性。

关键词: 高速公路, 密度控制, 反演变结构