Paolo Mercorelli

A Two-Stage Augmented Extended Kalman Filter as an Observer for Sensorless Valve Control in Camless Internal Combustion Engines

Camless internal combustion engines offer improvements over traditional engines in terms of improved torque performance and fuel economy, lower emissions, and pumping losses. Theoretically, their control flexibility provides electromagnetic valve actuators with the highest potential for improving efficiency. Sensorless control is one of the most important issues when implementing this new technology. The main contribution of this paper is a proposed observer comprising an augmented extended Kalman filter (EKF) and another EKF, which results in a sensorless control. The observer estimates the inductance of the actuator, which may vary. The proposed combination achieves a numerically efficient estimation. The proposed state observation structure avoids bulky and complicated measurement systems, which is an important advancement for real world applications. The introduced method is general and can be applied to problems in which it is not feasible or affordable to obtain position and velocity measurements. The current is measured, the position and the velocity of the electromagnetic valve are estimated with a robust method. The effectiveness of the proposed method is demonstrated using measured data acquired from an experimental setup based on an innovative electromagnetic valve actuator. A detailed comparative analysis of the arithmetic operations of the algorithm is also reported.

A Hysteresis Hybrid Extended Kalman Filter as an Observer for Sensorless Valve Control in Camless Internal Combustion Engines

Camless internal combustion engines offer improvements over traditional engines in terms of increased torque performance and fuel economy and of decreased emissions and pumping losses. The main goal of this project is to replace the camshaft system with electromagnetic actuators to control the intake and exhaust valves of internal combustion engines. Theoretically, electromagnetic valve actuators provide, with their control flexibility, the highest potential for improved efficiency. Sensorless control is one of the most important issues in implementations of this new technology. The main contribution of this paper is the proposal of a hysteresis hybrid observer to be applied for achieving a sensorless control. This observer consists of a combination of an extended Kalman filter with a hybrid automation. The proposed state-observation structure avoids bulky and complicated measurement systems, which is an important advancement for real-world applications. The introduced method is quite general and could be applied to other problems in which it is not feasible or affordable to obtain position and velocity measurements. In fact, in application with synchronous machines, such kind of an observer can represent a general approach to obtain a sensorless control. The proposed hysteresis strategy not only avoids chattering problems when the velocity is close to zero but also allows the use of unobservable sets and sets in which the observability level is too low to guarantee sufficient variation in the Kalman gains. The proposed structure consists of two models, each model containing two embedded switching conditions. The current is measured, and the position and the velocity of the electromagnetic valve are estimated. The effectiveness of the proposed method is demonstrated using measured data acquired from an experimental setup based on an innovative electromagnetic valve actuator.

An Antisaturating Adaptive Preaction and a Slide Surface to Achieve Soft Landing Control for Electromagnetic Actuators

Real-control applications of any nature can be affected by saturation limits that generate windup. When saturation occurs in a device its performance deteriorates. Electromagnetic actuators for industrial applications are being utilized ever more frequently for positioning and tracking control problems. One of the most important requirements in tracking trajectories is to achieve a soft landing, which guarantees reliable functionality and a longer component life. This paper presents an application of a typical electromagnetic actuator through a hardware-in-the-loop structure in which a soft landing is required in the tracking trajectory. To avoid saturation, which prevents soft landings, a specific new control law is developed. The proposed technique is based on a cyclic adaptive current preaction combined with a sliding surface. The technique consists of building a control law so that the position of the valve at which its velocity assumes its minimum is as close as possible to the landing point. At this time point, the magnetic force compensates for the elastic force and the preaction component is switched off. An experimental setup using a hardware-in-the-loop to allow a pilot investigation, model validation, and testing before implementation is considered. Real measurements of the proposed method are shown.

A Two-Stage Sliding-Mode High-Gain Observer to Reduce Uncertainties and Disturbances Effects for Sensorless Control in Automotive Applications

In this paper, a sensorless control of an electromagnetic valve actuator for automotive applications is presented. Based on a nonlinear model, a switching esti mator combined with a two-stage observer structure is proposed. The presented structure is basically a high-gain observer (HGO) to reduce the effects of the uncertainties on the electromagnetic valve actuator model and unmeasurable external disturbances coming from the burning phase of the engine and acting against the actuator movement. The proposed sliding-mode observer has the capability of guaranteeing zero average estimation error in finite time, even in the presence of model uncertainties and bounded disturbances. Considerations on constructive aspects concerning observability are made. Two constructive propositions are proven in this paper to realize the observer. A general comparative analysis is proposed, considering other contributions which use Kalman filters, in which aspects of optimality, robustness, and chattering problems are discussed. In particular, an analysis of the computational effort is also reported. Laboratory experiments of the controlled system, which demonstrate promising behavior, are presented and discussed for exhaust valves of an engine.

A Trajectory Generation Algorithm for Optimal Consumption in Electromagnetic Actuators

Camless internal combustion engines offer improvements over traditional engines in terms of torque performance, reduction of emissions, reduction of pumping losses and fuel economy. Theoretically, electromagnetic valve actuators offer the highest potentials for improving efficiency due to their control flexibility. For real applications, however, the valve actuators developed so far suffer from high power consumption and other control problems. One key point is the design of the reference trajectory to be tracked by the closed loop controller. In this brief, a design technique aimed at minimizing power consumption is proposed. A constrained optimization problem is formulated and its solution is approximated by exploiting local flatness and physical properties of the system. The performance of the designed trajectory is validated via an industrial simulator of the valve actuator.

Robust flatness based control of an electromagnetic linear actuator using adaptive PID controller

The paper presents the controller design for a high-force short-stroke linear actuator using permanent magnets as excitation. For the desired application a very high dynamic is required despite the presence of large disturbances. After the model description, a flatness based control is presented to force the system following a reference trajectory. Additionally, an adaptive feedback control, based on the PID structure and state observer, is used to stabilize the tracking against model uncertainties and external disturbance signals. A heuristic algorithm in receding horizon by using wavelets for online tuning of the controller parameters is proposed. Simulations using real data have been carried out to validate the proposed technique.

A hybrid actuator modelling and hysteresis effect identification in camless internal combustion engines control

This paper presents a hybrid actuator composed by a piezo and a hydraulic part. Moreover, a cascade PI-PID-PI control structure for camless engine motor applications is considered. The idea of this contribution is using the advantages of both: the high precision of the piezo and the force of the hydraulic part. Piezoelectric actuators (PEAs) are mostly used for precision positioning, despite PEAs’ non-linearities, such as saturations, hysteresis and creep. In the control problem these kinds of non-linearities must be taken into consideration. The Preisach dynamic model of the PEA with the above mentioned non-linearities is considered. In particular, the hysteresis effect is considered and a model with a switching function is used also for the controller design. Simulations and measured results are presented.

Design and control of an electromagnetic valve actuator

In this paper we present theoretical and experimental results for designing and operating a special linear electromagnetic motor as a variable engine valve actuator. Detailed description is given to the design procedure to meet the requirements of high dynamic and low power consumption, including the determination of actuator topology and parameters, the force, dynamic and power loss calculations. Based on a non-linear model a control strategy is presented and discussed as well. Both computer simulation and laboratory experimental results which demonstrate the excellent behavior of the developed system are presented.

A switching Kalman Filter for sensorless control of a hybrid hydraulic piezo actuator using MPC for camless internal combustion engines

This paper deals with a hybrid actuator composed by a piezo and a hydraulic part and with a switching Kalman Filter structure for camless engine motor applications. In the sensorless control problem, nonlinearities such as hysteresis, creep etc. must be taken into account. In this paper the Preisach dynamic model with the above mentioned hysteresis is considered together with a robust switching Kalman Filter utilized as an observer to manage the hysteresis nonlinearity. The control structure is realized using a Model Predictive Control strategy. Simulations with real data are shown.

A Motion-Sensorless Control for Intake Valves in Combustion Engines

This paper proposes a position observer and a velocity estimator of a nonlinear actuator for an application in a sensorless control system for engines. This is realized using a position observer and a velocity estimator combined in a cascade structure. The position observer is designed using a Lyapunov approach as typically done in the nonlinear observer approach. The velocity estimator is realized using the model of a proposed electromagnetic actuator. The Lyapunov-based observer estimates the valve position by using the coil current as an input signal and the estimated valve velocity as an output signal. The results are compared with an extended Kalman filter (EKF) used as an observer and developed for the same application. Moreover, the numerical complexity of the algorithm and the comparison with the developed EKF is also taken into account in the paper. The actuator is controlled using a discrete and analogous proportional derivative (PD) controller combined with a feedforward action to compensate for the stationer error. The final part of this paper contains validations of the proposed observed and controlled strategy by means of real measurements.