U OF M COLLEGE OF ENGINEERING
CONTROL SEMINAR SERIES
WINTER TERM 1998

Dr. Mrdjan Jankovic

Scientific Research Labs
Ford Motor Company

mjankov1@ford.com

Friday, February 6, 1998
4:00 - 5:00 pm
1200 EECS

Title: Robust Nonlinear Controller Design: Application to Diesel Engines

• Abstract
  
  A method of designing robust controllers for nonlinear systems is presented and applied to a simplified model of a diesel engine equipped with a variable geometry turbocharger (VGT) and an exhaust gas recirculation (EGR) valve. VGT varies the turbine flow area as a function of the engine operating condition thus providing improved fuel economy and faster torque response. EGR valve allows controlled recirculation of the exhaust gas into the intake manifold to reduce NOx emissions. However, simultaneous operation of the two actuators results in significant interactions. The control design problem is additionally complicated by inherently nonlinear nature of the diesel engine. As a result, two decoupled PID regulators have not been able to deliver satisfactory performance.

  Instead, the author proposes a recently developed robust control design method which applies to multi-input nonlinear systems with a known control Lyapunov function (CLF). The robustness guaranteed by the design is the nonlinear equivalent of the robustness of linear optimal regulators: the well known (1/2,infinity) gain margin and +/- 60° phase margin. This robustness to unmodeled dynamics allows simplification in the diesel engine model used for controller design. For one such model a CLF is constructed using the tools of geometric control theory. The resulting robust CLF based controller takes a very simple form. The talk will address the issues related to the controller design. Performance will be illustrated by simulations on a detailed model of a diesel engine.

  ---

  Biosketch

  
  Mrdjan Jankovic received the B.S. degree from the University of Belgrade, Yugoslavia, in l986 and the M.S. and D.Sc. degrees from Washington University, St. Louis, in l989 and l992. He held research positions with the University of Belgrade, l986-87, Washington University, l992-94, and the University of California, Santa Barbara, l994-95. In November l995, he joined Ford Scientific Research Laboratories, where he is currently working on the development of advanced powertrain control systems.

  Dr. Jankovic's research interests include nonlinear estimation, nonlinear and adaptive control with application to powertrain control systems design. He currently serves as an Associate Editor for IEEE Transactions on Control Systems Technology. With R. Sepulchre and P. V. Kokotovic he has co-authored the book "Constructive Nonlinear Control", Springer-Verlag, London, l997.

© UofM College of Engineering Control Research Group - December 1997
bethi@umich.edu