Experimental study and analytical model of bleed valve orifice influence of a high-performance shock absorber on vehicle dynamics

Abstract State of the art vehicle dynamics control systems do not exploit tire road forces information, even though the vehicle behaviour is ultimately determined by the tire road interaction. Recent technological improvements allow to accurately measure and estimate these variables, making it possible to introduce such knowledge inside a control system. In this paper, a vehicle dynamics control architecture based on a direct longitudinal tire force feedback is proposed. The scheme is made by a nested architecture composed by an outer Model Predictive Control algorithm, written in spatial coordinates, and an inner longitudinal force feedback controller. The latter is composed by four classical Proportional-Integral controllers in anti-windup configuration, endowed with a suitably designed gain switching logic to cope with possible unfeasible references provided by the outer loop, avoiding instability. The proposed scheme is tested in simulation in a challenging scenario where the tracking of a spiral path on a slippery surface and the timing performance are handled simultaneously by the controller. The performance is compared with that of an inner slip-based controller, sharing the same outer Model Predictive Control loop. The results show comparable performance in presence of unfeasible force references, while higher robustness is achieved with respect to friction curve uncertainties.

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Protocolo do experimento - CPBL/MA/FGAD (Projeto: Elaborar seminário de Biodiversidade) v2

10.17504/protocols.io.bzgvp3w6 ◽

2021 ◽

Author(s):

Geiser Chalco Challco

Keyword(s):

Experimental Study ◽

Collaborative Learning ◽

High Performance ◽

Group Formation ◽

Agile Methods ◽

Quasi Experimental ◽

Learning Projects

Main protocol in portugues used to conduct a quasi-experimental study of group formation of high performance in Collaborative-Learning-Projects with Agile Methods

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An analytical model for predicting the shear strength of unsaturated soils

Proceedings of the Institution of Civil Engineers - Geotechnical Engineering ◽

10.1680/jgeen.21.00135 ◽

2022 ◽

pp. 1-57

Author(s):

Tuan A. Pham ◽

Melis Sutman

Keyword(s):

Shear Strength ◽

Analytical Model ◽

Unsaturated Soils ◽

High Performance ◽

Micromechanical Model ◽

Experimental Studies ◽

Stress Equilibrium ◽

Proposed Model ◽

New Equation ◽

Multi Phase

The prediction of shear strength for unsaturated soils remains to be a significant challenge due to their complex multi-phase nature. In this paper, a review of prior experimental studies is firstly carried out to present important pieces of evidence, limitations, and some design considerations. Next, an overview of the existing shear strength equations is summarized with a brief discussion. Then, a micromechanical model with stress equilibrium conditions and multi-phase interaction considerations is presented to provide a new equation for predicting the shear strength of unsaturated soils. The validity of the proposed model is examined for several published shear strength data of different soil types. It is observed that the shear strength predicted by the analytical model is in good agreement with the experimental data, and get high performance compared to the existing models. The evaluation of the outcomes with two criteria, using average relative error and the normalized sum of squared error, proved the effectiveness and validity of the proposed equation. Using the proposed equation, the nonlinear relationship between shear strength, saturation degree, volumetric water content, and matric suction are observed.

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