Enhanced Continuous Higher Order Sliding Mode Control with Adaptation

This is the author accepted manuscript. The final version is availabel from Elsevier via the DOI in this recordThis paper proposes a new Continuous Adaptive HOSM control algorithm. The key advantage of the adaption scheme is that it does not require knowledge of the bounds on the matched uncertainty, and the gains themselves are not conservatively overestimated by the adaption scheme – which helps mitigate the problem of chattering. Compared with earlier work, two variable parameters are allowed to adapt and this facilitates much better self-tuning capabilities and improved closed-loop performance

Cyber-attacks and faults reconstruction using finite time convergent observation algorithms: Electric power network application

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordIn this work, linear (linearized) cyber-physical systems with output feedback control, whose sensors are experiencing faults or are under cyber-attack, are studied. Two different cases are investigated. First, when all sensors are attacked, then, when some sensors are protected from the attacks. Finite time convergent observers, specifically the sliding mode ones, including the observers with gain adaptation, are employed for on-line reconstruction of the cyber-attacks. The corrupted measured outputs are “cleaned” from cyber-attacks, and feedback control that uses the “cleaned” outputs is shown to provide elevated cyber-physical system performance close to the one without attack. Finally, the proposed methodology is applied to an electric power system under cyber-attack. Simulation results illustrate the efficacy of the proposed observers

On the Experimental Analysis of Integral Sliding Modes for Yaw Rate and Sideslip Control of an Electric Vehicle with Multiple Motors

With the advent of electric vehicles with multiple motors, the steady-state and transient cornering responses can be designed and implemented through the continuous torque control of the individual wheels, i.e., torque-vectoring or direct yaw moment control. The literature includes several papers on sliding mode control theory for torque-vectoring, but the experimental investigation is so far limited. More importantly, to the knowledge of the authors, the experimental comparison of direct yaw moment control based on sliding modes and typical controllers used for stability control in production vehicles is missing. This paper aims to reduce this gap by presenting and analyzing an integral sliding mode controller for concurrent yaw rate and sideslip control. A new driving mode, the Enhanced Sport mode, is proposed, inducing sustained high values of sideslip angle, which can be limited to a specified threshold. The system is experimentally assessed on a four-wheel-drive electric vehicle. The performance of the integral sliding mode controller is compared with that of a linear quadratic regulator during step steer tests. The results show that the integral sliding mode controller significantly enhances the tracking performance and yaw damping compared to the more conventional linear quadratic regulator based on an augmented singletrack vehicle model formulation. © 2018, The Korean Society of Automotive Engineers and Springer-Verlag GmbH Germany, part of Springer Natur

An impulsive input approach to short time convergent control for linear systems

The paper considers the problem of bringing the state of a controllable linear system to the origin in a very short time. It takes the approach of considering an “ideal” control input consisting of a linear combination of the Dirac delta function and its derivatives that realizes this goal instantaneously. Three schemes are introduced to approximate the impulsive input with physically realizable functions: a smooth approximation with compact support, a Gaussian function approximation and a step approximation. It is shown using a numerical example that all approximations work reasonably well, with the Gaussian approximation providing slightly worse results. It is also shown that a direct approach to obtain a state nulling input by solving an integral equation runs quicker into numerical problems than the impulsive input approach as the convergence time decreases. Finally, an application to an orbital rendez-vous problem is presented