Danijel Pavković

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.

Servo Pneumatic Position Control Using Fuzzy PID Gain Scheduling

In this paper, a design procedure and experimental implementation of a PID controller is presented. The PID controller is tuned according to damping optimum in order to achieve precise position control of a pneumatic servo drive. It is extended by a friction compensation and stabilization algorithm in order to deal with friction effects. In a case of supply pressure variations, more robust control system is needed. It is implemented by extending the proposed PID controller with friction compensator with the gain scheduling algorithm, which is provided by means of fuzzy logic. The effectiveness of proposed control algorithms is experimentally verified on an industrial cylindrical rodless actuator controlled by a proportional valve.

Modeling and Control of a Pneumatically Actuated Inverted Pendulum

This paper presents the results of modeling of an inverted pendulum system driven by a linear pneumatic motor and equipped with relatively low-cost potentiometer-based position measurement system. Based on the nonlinear model of the overall pendulum system, which also includes notable friction effects, a linearized model is derived. The linearized model is used as a basis for the design of state feedback controller based on LQ and LQG optimization procedures. The linear state feedback controllers are augmented by a compensator of nonlinear friction effects whose design is based on the results of experimental identification of an appropriate static friction model. The proposed pendulum controller structures have been verified by means of computer simulations and experimentally on the experimental setup of a pneumatically actuated inverted pendulum.

PID Controller Auto-Tuning Based on Process Step Response and Damping Optimum Criterion

This paper presents a novel method of PID controller tuning suitable for higher-order aperiodic processes and aimed at step response-based auto-tuning applications. The PID controller tuning is based on the identification of so-called n-th order lag (PTn) process model and application of damping optimum criterion, thus facilitating straightforward algebraic rules for the adjustment of both the closed-loop response speed and damping. The PTn model identification is based on the process step response, wherein the PTn model parameters are evaluated in a novel manner from the process step response equivalent dead-time and lag time constant. The effectiveness of the proposed PTn model parameter estimation procedure and the related damping optimum-based PID controller auto-tuning have been verified by means of extensive computer simulations.

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.

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.

A Model-Based Traction Control Strategy Non-Reliant On Wheel Slip Information

A traction control system (TCS) for two-wheel-drive vehicles can conveniently be realised by means of slip control. Such a TCS is modified in this paper in order to be applicable to four-wheel-drive vehicles and anti-lock braking systems, where slip information is not readily available. A reference vehicle model is used to estimate the vehicle velocity. The reference model is excited by a saw-tooth signal in order to adapt the slip for maximum tyre traction performance. The model-based TCS is made robust to vehicle modelling errors by extending it with (i) a superimposed loop of tyre static curve gradient control or (ii) a robust switching controller based on a bi-directional saw-tooth excitation signal. The proposed traction control strategies are verified by experiments and computer simulations.

A series-parallel hybrid electric vehicle control strategy including instantaneous optimization of equivalent fuel consumption

Control strategy for a series-parallel hybrid electric vehicle powertain aimed at operating the engine in its optimal fuel efficiency operating region is proposed in the paper. An instantaneous optimization algorithm based on the equivalent consumption minimization strategy (ECMS) is used in order to improve the hybrid vehicle fuel efficiency, and it is combined with a battery state-of-charge (SoC) controller to honor predefined SoC bounds. The effectiveness of the proposed control strategy is verified by means of computer simulations for three characteristic certification driving cycles.

Experimental analysis and modelling of longitudinal tyre friction dynamics for abrupt transients

A test vehicle has been used to collect experimental data related to abrupt engine throttle tip-in transients. The data point to a significant dynamic potential of the longitudinal tyre frictional force on an ice surface. Such a behaviour cannot be predicted by using the available brush-type dynamic tyre friction models. Based on the results of experimental and simulation analyses, the LuGre tyre friction model is extended to predict the dynamic friction potential. The extended model is validated against the experimental data.