The dynamics of hydraulic systems are highly nonlinear and the system may be subjected to non-smooth and discontinuous nonlinearities due to directional change of valve opening, friction, etc. Aside from the nonlinear nature of hydraulic dynamics, hydraulic servo systems also have large extent of model uncertainties. To address these challenging issues, a robust state-feedback controller is des...

This paper presents an indirect adaptive robust control (IARC) of electro-hydraulic systems driven by singlerod hydraulic actuators. Unlike the tracking-performanceoriented direct adaptive robust control (DARC) algorithm, in addition to good output tracking performance, the IARC also focuses on accurate parameter estimates for secondary purposes such as machine health monitoring and prognostics...

In this paper, the nonlinear sliding mode control (SMC) with mismatch disturbances is proposed. We treat the problem of control with this class of disturbances and the chattering phenomena. The proposed method attenuates the effect of both uncertainties, external disturbances and eliminates the chattering phenomenon introduced by classical sliding mode control. The model of a hydraulic system i...

Soil moisture memory is a key component of seasonal predictability. However, uncertainty in current memory estimates is not clear and it is not obvious to what extent these are dependent on model uncertainties. To address this question, we perform a global sensitivity analysis of memory to key hydraulic parameters, using an uncoupled version of the H-TESSEL land surface model. Results show sign...

This paper proposes the design of an observer to estimate the velocity of an electro-hydraulic system by using pressure measurements only. The difficulties involved in the design of an observer for such a system include the highly nonlinear system dynamics, severe parametric uncertainties such as large variation of inertial load and unmatched model uncertainties. In order to address these issue...

Global Sensitivity Analysis (GSA) methods are useful tools to rank input parameters uncertainties regarding their impact on result variability. In practice, such type of approach is still at an exploratory level for studies relying on 2D Shallow Water Equations (SWE) codes as GSA requires specific tools and deals with important computational capacity. The aim of this paper is to provide both a ...

There are several strategies for maintenance and repairing of devices in industry. However, they are still confronted with many uncertainties. A hydraulic lifting device after ten years of working in a technical center in Isfahan is faced with uncertainty in terms of reliability. Being able to know the reliability of pieces means predicting failure occurrences, which is accomplished by conditio...

In this paper, a reduced order linear model is selected to describe the hydraulic servo-actuator with large environmental uncertainties. The exploitation in simulation of the perturbed 5 order linear model is enough for the first approach, that is to say, before experimentation to value the studied law control potential. Because its robust character and superior performance in environmental unc...

In a general DIARC framework [13], the emphasis is always on the guaranteed transient performance and accurate trajectory tracking in the presence of uncertain nonlinearity and parametric uncertainties along with accurate parameter estimation for secondary purpose such as system health monitoring and prognosis. Need for accurate parameter estimation calls for the use of Least Square Estimation ...

Probabilistic Safety Assessment (PSA) is a mathematical tool to evaluate numerical estimates of risk for nuclear power plants (NPPs). For the last couple of years, PSA has been put to practical use for verification of safety in research and industrial fields. However, PSA still has the problems about the quality and reliability. The significant one of the problems is that the quantification of ...