Abstract. Soil hydraulic properties are often derived indirectly, i.e. computed from easily available soil with pedotransfer functions (PTFs), when those needed for catchment, regional or continental scale applications. When predicted parameters used the modelling of state and flux water in soils, uncertainty values can provide more detailed information drawing conclusions. The aim this study w...

The determination of the hydraulic properties of heterogeneous soils or porous media remains challenging. In the present study, we focus on determining the effective properties of heterogeneous porous media at the Darcy scale with an analysis of their uncertainties. Preliminary, experimental measurements of the hydraulic properties of each component of the heterogeneous medium are obtained. The...

flow and sediment transport processes are different and more complex in coarse-bed rivers than in sand-bed rivers. the main goal of the present study is to evaluate different modes of sediment transport using different hydrometric and hydraulic methods, and to address the major uncertainties. four river reaches were selected as representatives of coarse-bed rivers in the northwest of iran. a se...

The rehabilitation exoskeleton is an effective piece of equipment for stroke patients and the aged. However, this complex human–robot system incurs many problems, such as modeling uncertainties, unknown interaction, external disturbance, actuator fault. This paper addresses adaptive fault-tolerant tracking control a lower limb joint driven by electro-hydraulic (EHA). First, model built consider...

In this paper a discrete-time design of continuous-time delay (TDC) is presented. The main goals are: (i) to eliminate the TDC assumption of accessibility to all the delayed derivative of the plant state variables, and (ii) to design discrete-time controllers based on approximate discrete-time models. Simulations results are given, for an articulated arm actuated with linear hydraulic motors wi...

1 2 This paper describes the design of and some preliminary control results for a hydraulically actuated human power amplifier. The system is in the form of an oar, with its reach and pitch degrees of freedom being hydraulically assisted. A robust PI force controller is proposed so that the hydraulic actuator force tracks a scaled copy of the force exerted by the human. Nonlinearities and uncer...

Uncertainties in the values of the parameters of a system can originate from the manufacturing tolerances of the system components, which can produce a degree of unreliability in the performance of the system. A systematic framework for realistic reliability assessment of an electro-hydraulic servo system has been presented in this paper with the objective of providing adequate information for ...

The characteristics of hydraulic turbine governing system change with operating conditions, therefore the governor must be capable of providing satisfactory control under different operating points. For this reason a design method of robust PID controller is proposed. The effects of the characteristic variations are defined as uncertainties in the system model, and based on this model, the requ...