Stochastic stability for a model representing the intake manifold pressure of an automotive engine

The paper presents conditions to assure stochastic stability for a nonlinear model. The proposed model is used to represent the input-output dynamics of the angle of aperture of the throttle valve (input) and the manifold absolute pressure (output) in an automotive spark-ignition engine. The automotive model is second moment stable, as stated by the theoretical result—data collected from real-time experiments supports this finding.Peer ReviewedPostprint (author's final draft

Semi-active magnetic levitation system for education

This paper describes how to construct a low-cost magnetic levitation system (MagLev). The MagLev has been intensively used in engineering education, allowing instructors and students to learn through hands-on experiences of essential concepts, such as electronics, electromagnetism, and control systems. Built from scratch, the MagLev depends only on simple, low-cost components readily available on the market. In addition to showing how to construct the MagLev, this paper presents a semi-active control strategy that seems novel when applied to the MagLev. Experiments performed in the laboratory provide comparisons of the proposed control scheme with the classical PID control. The corresponding real-time experiments illustrate both the effectiveness of the approach and the potential of the MagLev for education.Peer ReviewedPostprint (published version

Stabilization of two-dimensional nonlinear systems through barrier-function-based integral sliding-mode control: application to a magnetic levitation system

The sliding-mode control (SMC) has been used successfully to stabilize nonlinear systems, yet a side effect of SMC is chattering, an undesired phenomenon. Researchers have then introduced the so called integral-type approach to diminish chattering. Additional studies have shown that SMC with the socalled barrier function can drive the system state to a region close to the origin. The main contribution of this paper is to join both setups in the context of SMC, i.e., integral term and barrier function. We show that SMC with both integral term and barrier function can be used to track any given trajectory while ensuring both stability and chattering-free performance. The potential of this novel control for applications is illustrated through real-time experiments performed on a magnetic levitation system.Postprint (author's final draft

Low-cost dual-axis solar tracker with photovoltaic energy processing for education

Converting the sunlight into electricity has gained the world’s agenda—institutions and individuals have been relying on solar technology more than ever. Still, few workers are qualified to face the increasing demand for solar technology—the high cost of photovoltaic solar technology impedes the creation of more educational programs to qualify more people. To help foster photovoltaic engineering education, we show how to construct a low-cost photovoltaic kit for education. This paper documents the steps necessary to build a low-cost solar tracker and how to process the energy it generates. The equipment has a total cost of about US$ 720. This paper emphasizes the necessary features a solar tracker must have, such as collecting and processing photovoltaic energy, in an optimal way. Using real-time data, we have identified a linear system to represent the dynamics of the sun-tracker equipment. This linear model feeds the algorithm that controls the sun-tracker. Experimental data confirm the effectiveness of the designed solar tracker equipment for extracting the maximum amount of photovoltaic energy—the data indicate an improved energy efficiency of about 32%. The proposed equipment requires only low-cost spare parts, a clear benefit for the education on photovoltaics.Peer ReviewedPostprint (author's final draft