Esfandiar Shafai

Extended Multiple Model Adaptive Estimation for the Detection of Sensor and Actuator Faults

A combination of the multiple model adaptive estimation method (MMAE) with an extended Kalman filter (EKF) is considered. The ability of the MMAE method to detect faults based on a predefined hypothesis and the parameter-estimating ability of an EKF results in a very efficient fault detection approach. This so-called extended multiple model adaptive estimation method (EMMAE) has been investigated on a nonlinear model of an aircraft. The results show that it is a very capable method to detect faults of various types.

MODEL OF A CONTINUOUSLY VARIABLE TRANSMISSION

Abstract For the purpose of controller design for a continuously variable transmission a mathematical model consisting of the hydraulic as well as the mechanical subsystem of a continuously variable transmission is presented. Modularity and avoidance of algebraic loops in the simulation model are achieved due to a deductive modelling. The simulation results for both steady state and dynamic behavior of the model are presented and compared with measurement results.

Adaptive control of a three-way catalytic converter

The three-way catalytic converter (TWC) is an effective device for reducing exhaust emissions in automobiles. For control purposes, the TWC can be regarded as an oxygen storage device. In order to reduce exhaust emissions efficiently, the oxygen storage should neither be completely full nor totally empty. Based on a simple model for oxygen storage in the TWC, an adaptive scheme for the control of the oxygen level is presented. The parameters involved in the model for oxygen storage are identified online by measuring the air-to-fuel ratios upstream and downstream of the TWC and using a recursive Gauss-Newton estimation method.

Control Issues in a Fuel-Optimal Hybrid Car

Abstract In this paper, the salient features of the Hybrid III car developed at the Swiss Federal Institute of Technology (ETH), Zurich, Switzerland, are summarized. It is shown how the position of the accelerator pedal can be interpreted as a demand for the driving torque in the main operating modes of the vehicle. In a hierarchical control scheme the driver interpretation yields setpoint signals for the control of the rate of change of the transmission ratio of the CVT. The control of the CVT is discussed briefly. Extensive simulation results validating the proposed schemes are presented.

detectNARMAX: A graphical user interface for structure detection of NARMAX models using the bootstrap method

Abstract This paper describes a MATLAB-based program called detectNARMAX that utilizes the bootstrap method, a numerical procedure for estimating the distribution of statistical parameters, to find the best NARMAX model structure representing the nonlinear behavior of a system using its noisy input-output data. The performance of the bootstrap-based structure detection techniques is demonstrated by using synthetic data generated by simulation as well as real data measured to determine a model structure for the thermal impact on a sensor system.