For modern Diesel engines, accurate fuel-air ratio $AFR$ and Exhaust Gas Recirculation $(EGR)$ rates control is important for manufacturers to face a more restrictive legislation levels . To fulfill the requirements, hardware devices such ($EGR$) and Variable Geometry Turbochargers ($VGT$) valves have been introduced, and sophisticated control algorithms were designed. The main objective of the air path controller is to regulate in the intake manifold the $AFR$ ratio and the $EGR$ fraction rates to their desired values. Earlier $EGR$ PID controllers needed a fastidious and time consuming calibration step for each engine operating point. Nonlinear control algorithms has quickly appeared as a promising way to provide an efficient air path controllers, since they don't need a calibration step . The main drawback of such controllers is coming from the fact that they are based upon a diesel engine model which handles parameters uncertainties and signal measurements errors, that affects the control performance. In this paper we propose a novel control scheme for controlling the diesel engine air path. Control design is carried out under the sliding mode framework. The proposed controller has been tested on the Jankovic Tubocharged Diesel Engine (TDE) model. To demonstrate the robustness of the proposed controller, simulation results showing the tracking of the compressor flow $W_c$ and the exhaust manifold pressure $p_{2}$ variables are presented

 Solutions of the output regulation problem in a nonlinear setting invariably target systems presented under some normal form. This paper reviews a recently introduced such form for MIMO nonlinear systems and discusses consequent necessary conditions for solving the MIMO nonlinear output regulation problem. As opposed to the (by now classic) form based on the notion of vector relative degree that is only specific to some square invertible MIMO nonlinear systems, the recent form applies to general (not necessarily invertible, nor square) systems. It turns out that, as far as output regulation goes, the recent form fits better some assumptions that have already been used in the context of square invertible systems and, more important, that can still be used (thanks to this particular normal form) in the context of not square ones.

 This paper presents a new antiwindup (AW) speed controller for salient-pole Synchronous Machine (SM) with rotor field winding. The control method is based on antwindup methodology using a sliding mode observer for controller gain adaptation. All the system variables are expressed in a γδ estimated rotating reference frame. Firstly, the unwanted windup phenomena due to the physical limitations are eliminated choosing suitably the controller transfer function. Secondly the speed converges asymptotically leading the saturation element very fast towards to the linear area of the actuator using a relatively simple AW control method. Simulation results demonstrate the effectiveness of the proposed antiwindup speed control method using Matlab/Simulink facility.

 The purpose of this paper is to provide theoretical framework enabling to design tracking feedback for a general Acrobot trajectory which allow rigorous convergence proof. It is based on the partial exact feedback linearization of the Acrobot model followed by further approximate feedback linearization of the tracking error dynamics for arbitrary target trajectory. The approach presented here enables to prove the convergence in a rigorous way at least for small initial tracking errors. The slight novelty here is that neglecting is made with respect to tracking error along any general trajectory to be tracked, not just in some neighborhood of fixed working point. To demonstrate viability of this approach, the simulations of tracking of walking-like cyclic trajectory are presented. The walking includes several steps and impact and the exponential stable tracking during the swing phase only is capable to stabilize overall walking, including the effect of impact.

 The dynamic friction in motion systems is mostly not directly measurable and has to be observed for an efficient compensation. A novel feed-forward friction observer (FFFO) is proposed based on the two-state dynamic friction model with elasto-plasticity abbreviated by 2SEP friction model. Being involved in the underlying closed control loop the FFFO uses the control error to adjust the friction dynamics which is computed in feed-forwarding based on the reference velocity. The friction compensation is evaluated on the actuated motion system with multiple coupled frictional surfaces. The proposed FFFO approach proves to be superior in comparison to the common friction observer which uses the output velocity value.