Optimal weakening and damping using polynomial control for seismically excited nonlinear structures

This paper presents an approach for the optimal design of a new retrofit technique called weakening and damping that is valid for civil engineering inelastic structures. An alternative design methodology is developed with respect to the existing ones that is able to determine the locations and the magnitude of weakening and/or softening of structural elements and adding damping while insuring structural stability. An optimal polynomial controller that is a summation of polynomials in nonlinear states is used in Phase I of the method to reduce the peak response quantities of seismically excited nonlinear or hysteretic systems. The main advantage of the optimal polynomial controller is that it is able to automatically stabilize the structural system. The optimal design of a shear-type structure is used as an example to illustrate the feasibility of the proposed approach, which leads to a reduction of both peak inter-story drifts and peak total accelerations.

Analysis and Control of the Vehicle Roll Dynamics Using Sum of Squares Polynomial Approach

The safety of vehicle travel relies on good stability performance,making vehicle motion control a vital technology in vehicles.This paper focuses on investigating the impact of roll control on vehicle performance,particularly in terms of avoiding rollover and ensuring lateral stability.By introducing a feedback roll moment,the roll motion can be effectively controlled.The paper considers two roll reference generators:A static one aimed at zero roll,and a dynamic one based on the vehicle's lateral acceleration.The static roll reference generator enhances stability by employing a fixed reference,particularly beneficial during routine driving conditions.In contrast,the dynamic roll reference generator continually adapts the roll angle reference in response to real-time vehicle dynamics and driving conditions.These proposed reference generators can be paired with varying suspension systems—Static reference could be achieved using semi-active suspensions,while the dynamic one is integrated into advanced active suspension systems,offering heightened adaptability and performance.To address the roll control objectives,this paper proposes a novel sum of squares(SOS)integral polynomial tracking control.The proposed controller satisfies control bounds and considers control constraints during the design phase.The effectiveness and robustness of the proposed control scheme are evaluated through numerical simulations using a full vehicle nonlinear model in Matlab/Simulink.The results of these simulations are compared to super-twisting sliding mode and Lyapunov-based controllers.

Supercapacitors and Battery Energy Management Based on New European Driving Cycle

This paper presents a new strategy of embedded energy management between battery and supercapacitors （SC） for hybrid electric vehicles （HEV） applications. This proposal is due to the present trend in the field, knowing that the major drawback of the HEV is the autonomy problem. Thus, using supercapacitors and battery with a good energy management improves the HEV performances. The main contribution of this paper is focused on DC-bus voltage and currents control strategies based on polynomial controller. These strategies are implemented in PICI8F4431 microcontroller for DC/DC converters control. Due to reasons of cost and available components （no optimized）, such as the battery and power semiconductors （IGBT）, the experimental tests are carried out in reduced scale （2.7 kW）. Through some simulations and experimental results obtained in reduced scale, the authors present an improved energy management strategy for HEV.