PID Control Strategy of Vehicle Active Suspension Based on Considering Time-Delay and Stability

The stability conditions of 1/4 vehicle active suspension with time-delay were deduced by the theory of Routh-Hurwitz stability criterion and the critical instability time-delay was discussed and calculated. Compared with PID control method of without time-delay the simulation results show that when the critical time-delay is 0.153s, the amplitude range and its root mean square value of spring load quality vertical acceleration were increased 1.2 times or so and the system was being on the critical stability. The calculation and simulation results proved that the theory of Routh-Hurwitz stability criterion laid a foundation for the design and instability mechanism of active suspension.