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A crucial problem in immersion based observer design is the case where the dimension of the immersed system is greater than that of the original system, and the analytical expression of the inverse of the immersion is unknown. In this paper, we have proposed a method for constructing observers for such autonomous nonlinear systems.

This paper presents an observer-based fault reconstruction method for PEM fuel cells. This method extends the results of a class of nonlinear uncertain systems with Lipschitz nonlinearities. An adaptive-gain second-order sliding mode (SOSM) observer is developed for observing the system states, where the adaptive law estimates the uncertain parameters. The inherent equivalent output error injection feature of SOSM algorithm is then used to reconstruct the fault signal. The performance of the proposed observer is validated through a hardware-in-loop emulator. The experimental results illustrate the feasibility and effectiveness of the proposed approach for application to fuel cell air-feed systems.

Summary In this paper, we present an output feedback backstepping controller for mechatronic actuators with dynamic adaptive parameters for friction and load compensation. The targeted application is angular position control of automotive mechatronic valves, which possess nonlinear dynamics due to friction. The proposed controller requires only position measurement. The velocity, current, and friction dynamics are obtained by estimation and observation. The adaptive control law compensates the variations in friction behavior and load torque variation, which are common in real life applications. Lyapunov analysis has been used to show the asymptotic convergence of the closed-loop system to zero. Simulation and laboratory experimental results illustrate the effectiveness and robustness of the controller. Further experiments on an engine test bench demonstrate the applicability of this controller in commercial engines, as well as its effectiveness as compared with conventional PI controllers.Copyright © 2014 John Wiley & Sons, Ltd.

In this paper, we design, analyze, and experimentally validate an observer-based backstepping controller for electropneumatic actuators. These actuators are commonly used in diesel engines for variable geometry turbochargers (VGT) control. They are preferred over other actuation techniques due to better force/weight ratio; however, their drawbacks, such as nonlinear air mass flow, friction, and aerodynamic forces make their control as a challenging problem. The aim of this paper is to achieve precise control of the actuator by compensating friction and aerodynamic VGT forces. A Lyapunov-based output feedback controller is developed using backstepping technique. As the actuator position is the only measured state, pressure and friction states are obtained from sliding mode-based observers. The exponential convergence of the controller-observer closed-loop system is proved using Lyapunov analysis. Experimental results are presented, which demonstrate the effectiveness of the proposed controller.

Numerous advanced control techniques for actuator control of an engine’s air path have been developed in recent years. Among these approaches, the performance of sliding mode controllers stands out due to their robustness against changes in the physical conditions around the engine. This paper presents the design and testing of three high-order sliding mode controllers and a comparison of their performance in controlling a mechatronic engine air path valve. The most effective strategies are further tested for their robustness against variations in temperature and load conditions. The experimental results show the effectiveness and robustness of the controllers. Comparative results are presented that allow the performance of the considered algorithms to be compared both with respect to each other and with respect to sliding surfaces.

This article is focused on the working, modeling and control of pancake DC torque motors, used in automobile engine air path actuators. These motors, with a limited working angle, provide high torque which makes them suitable for use in actuators without any additional gear reduction. The torque is a nonlinear function of the motor angle. This article provides a modeling scheme, suitable for control purposes, which takes into consideration nonlinearities arising from friction and operating temperature. Comparison between simulation and experiments shows the effectiveness of the proposed model. Second order sliding mode control has been applied to the actuators for robust control under the influence of nonlinearities and uncertainties. The effectiveness of the control algorithm has been proven experimentally.

International audience; In this brief, we present Lyapunov-based robust and adaptive higher order sliding mode (HOSM) controllers for the air-feed system of polymer electrolyte membrane fuel cells, which is a nonlinear single-input, single-output system with bounded uncertainty. The system consists of a motorized compressor, which is driven at its optimal point in order to minimize the internal energy consumption of the system. This brief provides an experimental demonstration of the applicability of the recently developed fixed-gain robust controller and adaptive controller for this problem. Third-order controllers are developed in order to obtain a continuous profile for the input current of the compressor motor. In this regard, a complete adaptive arbitrary HOSM control has been presented for the first time, with Lyapunov-based proof. A performance comparison between the two controllers is presented in the end.