Research On Multi Rate Control Method Of High-speed Train Active Suspension

With the speeding up of high-speed train, people have higher demand on theanti-vibration and noise reduction technology of the train. The active suspension technologyinstead of traditional passive suspension technology is an inevitable trend in the developmentof the train. However, the active suspension is an active vibration control system withcomputer as its core, which equipment structures are complex, it is not practical to use asingle sampling period in such a complex and multivariate computer control system.Generally, the shorter the sampling period, the better the control quality, but it will increasethe active vibration control system’s complexity and cost. Therefore, the multi rate digitalcontroller was designed in the paper, and research on multi rate control method of high-speedtrain active suspension was carried out to optimize the damping property of train and the ridecomfort of passengers.The vertical&lateral track stochastic irregularity excitation were adopted to be theinterference excitation of high speed train. Taking the train’s single vehicle as research object,the continuous-time system models of the high-speed train’s vehicle vertical&lateral activesuspension were established respectively, in which the former model was setted the vehiclebody vertical displacement and nod angular displacement as output variables, the latter onewas taken the vehicle body roll angular displacement as output variable. The abovecontinuous system state equations were discretized by the step unchanged discretizationmethod, then the lifting technique of multi rate digital system was adopted, and finally thedynamic state space models of vertical&lateral active suspension multi rate systems werededuced respectively.The controllability and observability of the vertical&lateral active suspension multi ratesystems were calculated and analyzed according to the controllability and observabilitycriterion of general discrete system. Then, the distribution of the poles is discussed and thestability condition of active suspension multi rate system dynamics model which consideringperturbation and time-delay were analyzed. Finally, the output performance contrastsimulation were carried out before control among three different control systems, which wererespectively the continuous time system, discrete single rate system and multi rate system.The results show that the active suspension multi rate system is improved in vibration controlperformance and response speed, as compared with the discrete single rate system.The weighting matrix Q and R were optimal selected by using the genetic algorithmtoolbox. Aiming at the vertical&lateral active suspension continuous time, discrete singlerate and multi rate systems, the optimal feedback weight matrix was solved respectively, and the optimal controllers of the three different active vibration control systems were obtained.Then the contrast simulation was taking on control output effects of the vehicle body verticaldisplacement, nod angular displacement and roll angular displacement by SIMULINK.Simulation results showed that the designed controllers were effective, and the results aftercontrol also showed that the multi rate digital system had the advantage of control accuracy.Finally, a simple experimental verification platform of the electromagnetic damping activesuspension was setted up based on the principle of electromagnetic damping，and the researchon experimental comparison between single rate and multi rate was carried out. The resultsshow that the multi rate digital system has a certain influence on the vibration control effect ofthe suspension system, and the multi rate system is better than the single rate vibration controlsystem.