Abstract:The vehicle nonlinear suspension system is taken as the research object, the dynamic characteristics of the system time-delayed instantaneous optimal control are studied by the method of combining theory with simulation. Firstly, the cubic polynomial model is used to describe the nonlinear characteristics, and the dynamic equation of vehicle nonlinear suspension system with time delay in the control loop is established. Secondly, the time delay is dealt with state transformation. Then the time-delayed instantaneous optimal control strategy is designed by using optimal control theory and Runge-Kutta method. Finally, the state transmission of the system under deterministic and stochastic excitation is analyzed by numerical simulation. The results show that the time-delayed instantaneous optimal control can ensure the stability of the system, and the optimal control weight matrix can obtain better damping performance. Moreover, the research lays a foundation for the study of the time delay as the control input parameter, and provides a new idea for the active damping. The study has important theoretical and engineering application value.