Joško Deur

An electronic throttle control strategy including compensation of friction and limp-home effects

An electronic throttle is a low-power dc servo drive which positions the throttle plate. Its application in modern automotive engines leads to improvements in vehicle drivability, fuel economy, and emissions. Transmission friction and the return spring limp-home nonlinearity significantly affect the electronic throttle performance. The influence of these effects is analyzed by means of computer simulations, experiments, and analytical calculations. A dynamic friction model is developed in order to adequately capture the experimentally observed characteristics of the presliding-displacement and breakaway effects. The linear part of electronic throttle process model is also analyzed and experimentally identified. A nonlinear control strategy is proposed, consisting of a proportional-integral-derivative (PID) controller and a feedback compensator for friction and limp-home effects. The PID controller parameters are analytically optimized according to the damping optimum criterion. The proposed control strategy is verified by computer simulations and experiments.

A 3D Brush-type Dynamic Tire Friction Model

The use of advanced dynamic friction models can improve the brush-type tire friction models. This paper presents a 3D dynamic brush model based on the LuGre friction model. The model describes the dynamics of longitudinal and lateral tire friction forces, as well as the self aligning torque dynamics. It has been originally derived in a distributed-parameter form, and then transformed to a simpler lumped-parameter form with only three internal states. Both uniform and non-uniform normal pressure distributions are considered. The model has analytical solution for steady-state conditions. The steady-state behavior is validated with respect to “magic” formula static model, which served as an “ideal” benchmark. The lumped model dynamic behavior is validated by comparing its time-responses with original distributed model responses. The model parameterization with respect to normal force and other tire/road parameters is considered as well.

Modeling and Analysis of Automatic Transmission Engagement Dynamics-Linear Case

A control-oriented model of a typical four-speed automatic transmission is developed by using the bond graph modeling method. The planetary gear set model utilizes the Karnopp friction model for hydraulic and one-way clutches, in order to provide a favorable computing efficiency. The full gear set model is reduced for various phases of the park/ reverse and park/drive engagements. The reduced gear set models and linearized torque converter model are used as a basis for an algebraic analysis of the engagement dynamics. The analysis is originally conducted for the basic case of fully applied brake, and it is then extended by an analysis of the influence of wheel dynamics in the brake-off case. The analysis results are verified by computer simulations and experiments.

Modeling of Wet Clutch Engagement Including a Thorough Experimental Validation

A detailed experimental validation has been carried out to point to limitations of static wet-clutch friction model for typical clutch engagement transients. The model accuracy can be increased by incorporating the fluid film dynamics, as done in the lumped-parameter dynamic clutch model developed at the University of Purdue. That model is extended herein in order to increase its accuracy especially in the case of grooved clutches. The extensions include a description of clutch actuator dynamics and introduction of an empirical scaling factor for the fluid film thickness state equation. More rigorous treatment of fluid dynamics for the grooved clutch is also presented.

Adaptive Kalman Filter-Based Load Torque Compensator for Improved SI Engine Idle Speed Control

This paper presents design of an SI engine load torque estimator based on an adaptive Kalman filter. The adaptive estimator is characterized by a fast response and good noise suppression ability. The estimator is used to establish a fast load torque compensation path within a proportional-plus-integral (PI) controller-based idle speed control system. The proposed adaptive controller has been verified by means of experiments, and compared with PI, PID and polynomial controllers. The experimental results point out to favorable performance of the adaptive controller for a wide engine operating range.

Recent Advances in Control-Oriented Modeling of Automotive Power Train Dynamics

This paper presents a survey of the recent research results of the authors in the field of modeling of automotive power train systems and components. The goal of the research is to propose simple and accurate power train models for controller design and to propose computationally efficient simulations. The modeling includes typical power train components such as electronic throttle, SI engine, torque converter, planetary gear set, wet clutch, differential, half shaft, and tire. Experimental model validation results are presented

MODELING AND ANALYSIS OF LONGITUDINAL TIRE DYNAMICS BASED ON THE LUGRE FRICTION MODEL

Abstract A brush representation of the longitudinal tire dynamics model is discussed in thepaper. It is shown that the dynamic tire model can be derived from any dynamic friction model in a straightforward way. Modification of the recently published tire model based on the LuGre friction model is proposed, resulting in a consistent lumped form of the tire modeL Based on the Iinearized lumped tire model, an analysis of the influence of tire dynamics on overall vehicle dynamics behavior is carried out.

Self-tuning control of an electronic throttle

A self-tuning strategy for an electronic throttle servo-system is proposed in order to account for the variations of DC motor armature resistance, battery voltage, and limp-home position. Different self-tuning algorithms have been derived depending on the availability of armature current sensor and control strategy auto-tuning procedure. The presented self-tuning algorithm has been experimentally verified on an experimental setup of electronic throttle control system. For the purpose of experimental verification, a real-time simulator of process parameters variations has been developed.

Design of a power-split hybrid electric vehicle control system utilizing a rule-based controller and an equivalent consumption minimization strategy

The paper proposes a power-split hybrid electric vehicle control strategy that combines a rule-based controller, including a state-of-charge controller and engine start–stop logic, with a precisely formulated equivalent consumption minimization strategy. A one-dimensional directional search-based instantaneous equivalent consumption minimization strategy optimization and a two-dimensional directional search-based instantaneous equivalent consumption minimization strategy optimization are used to find optimal powertrain points in high-efficiency engine map regions that are previously determined by an offline optimization approach. The simulation results confirm that the rule-based controller performance can be significantly improved when extended with the proposed equivalent consumption minimization strategy formulation, without requiring an adaptive empirical penalty factor to satisfy the state-of-charge sustainability condition. The proposed rule-based + equivalent consumption minimization strategy control strategies were verified against a dynamic-programming-based optimization benchmark for different certification driving cycles.

Modeling and Analysis of Active Differential Dynamics

Active differentials are used to improve the overall performance of traction control and vehicle dynamics control systems. This paper presents the development of a unified mathematical model of active differential dynamics using the bond graph modeling technique. The study includes active limited slip differential and various common types of torque vectoring differentials. Different levels of model complexity are considered, starting from, a second-order model with lumped input and output inertia toward higher-order models including the gear inertia and half-shaft compliance. The model is used for a theoretical analysis of drivability and time response characteristics of the active differential dynamics. The analysts is illustrated by simulation results.