Simulating Process and Engine Control Applications using Multivariable Control Algorithms Model Predictive Control (MPC) is a multivariable control algorithm that uses computational models to represent the process control behavior of complex dynamical systems such as chemical plants, oil refineries and engines. Standard MPC approaches depend heavily on prediction model accuracy and can have issues regarding achievement of zero steady state tracking error. Because of this, Rate-based MPC that uses fewer predictive linear models while achieving better computational cost efficiency is being more desirable for simulating steady state behavior seen in systems like engine control applications. Thus, for the >$20B Internal Combustion Engine industry new Rate-based MPC technology can play an important role in diesel engine applications.
Optimal Rate Based Model Predictive Control for Diesel Air Path Researchers at the Department of Aerospace Engineering of the University of Michigan have developed a Rate-based MPC method for diesel air path control. Using this control method the optimal rate for which the VGT and EGR valve should change position is predicted. The proposed approach guarantees zero steady state tracking error of outputs, intake pressure and EGR rate, and uses fewer local linear models while maintaining similar performance compared to existing technologies. It avoids adding integral states to the model of outputs, reducing the computational cost and eliminating issues of integrator windup compensation which is typical of standard MPC approaches. Furthermore, being less dependent on the prediction model accuracy results in both reduced ECU memory requirements and reduced controller calibration time. In conclusion, achieving good steady-state tracking behavior while maintaining computational cost efficiency makes the proposed Rate-based MPC approach an optimal method for diesel air path control.
Applications • Diesel engine control
Advantages • Guaranteed zero steady state error • Reduced computational cost • Reduced calibration time