Research On Diesel Engine Speed Control Strategy Based On Model Predictive Control

The power performance and emission performance of diesel engine are closely related to the development and application of intelligent control,and the closed loop control of diesel engine speed is the most important part of intelligent control of diesel engine.With the continuous improvement of the control performance in nowadays controlled object,the traditional PID algorithm can not meet the current control requirements.This paper based on nonlinear model predictive control and research the closed-loop control strategy of diesel engine speed,in order to improve the transient rate adjustment and reduce the steady fluctuation of diesel engine speed control.The control effect is verified by Model-Based Design and part of flow in V mode.First of all,build the zero-dimensional model of YC6 high pressure common rail diesel engine,the diesel engine system is divided into fuel subsystem,intake and exhaust system,cylinder system and rotor dynamics system.Diesel model compared with the real machine,the steady-state error is up to 2.8% and the transient error is up to 4.2%,which meet the simulation accuracy of the real-time model.Secondly,according to the control requirements of diesel engine speed and the control principle of model predictive control,NARX neural network was used to build the prediction model required by the controller.Above all,the diesel engine model was used to output the fuel injection quantity and the corresponding variable of diesel engine speed for the identification of the prediction model,The accuracy of NARX prediction model is verified by synchronous operation with diesel engine model.In order to make the control strategy run in the Rapid Control Prototype system,use the particle swarm optimization algorithm to solve the optimal control sequence of the controller combined with the prediction sequence of the prediction model.Finally,the effect of MPC speed controller based on MODEL predictive control was verified by offline simulation.The simulation results show that MPC speed controller has faster speed response and smaller speed overshoot than PID controller.Finally,in order to verify the actual control effect of MPC speed controller,the MPC speed controller and PID controller are compared and analyzed on the semi-physical simulation platform.The experiment shows that MPC controller can achieve better speed tracking under different working conditions than traditional PID control.The steady fluctuation of rotational speed is decreased while the response speed is improved.Finally,the RCP platform and the experimental bench were used to verify the actual machine configuration.Through acceleration and deceleration,step of target speed and load loading and unloading experiments,the actual control effect of MPC controller is verified.The results show that MPC speed controller has good steady-state characteristics and improves the dynamic response speed.