Based on artificial neural networks, a fault diagnosis approach for the hydraulic system was proposed in this paper. Normal state samples were used as the training data to develop a dynamic general regression neural network (DGRNN) model. The trained DGRNN model then served as the fault determinant to diagnose test faults and the work condition of the hydraulic system was identified. Several ty...

The model of West, Brown and Enquist showed that total hydraulic resistance in trees can be independent of path length, provided that vascular conduits taper sufficiently. This model assumes that the tree branch network is volume-filling, so that segment lengths increase exponentially from tree top to base. We show that partial buffering of hydraulic resistance from path-length effects can occu...

This paper details the new design and dynamic simulation of an electro-hydraulic camless engine valve actuator (EH-CEVA) and experimental verification with lift position sensors. In general, camless engine technologies have been known for improving fuel efficiency, enhancing power output, and reducing emissions of internal combustion engines. Electro-hydraulic valve actuators are used to elimin...

A position-based impedance controller is proposed and demonstrated on an existing hydraulic press with a two-way vertically mounted hydraulic cylinder driven by a servo-solenoid valve. A proportional-integral-derivative (PID) controller and a Fuzzy Logic Controller (FLC) are primarily developed to meet the accurate positioning requirements of the impedance control formulation. The impedance fil...

Both engineered hydraulic systems and plant hydraulic systems are protected against failure by resistance, reparability, and redundancy. A basic rule of reliability engineering is that the level of independent redundancy should increase with increasing risk of fatal system failure. Here we show that hydraulic systems of plants function as predicted by this engineering rule. Hydraulic systems of...

Illman and Tartakovsky (2005a, 2005b) developed a new approach for the interpretation of three-dimensional pneumatic well tests conducted in porous or fractured geologic media, which is based on a straight-line analysis of late-time data. We modify this approach to interpret three-dimensional well tests in the saturated zone and use it to analyze the cross-hole hydraulic test data collected in ...

Abstract. This work presents a cascade controller for the trajectory tracking control of a hydraulic actuator by using adaptive algorithms to deal with parametric uncertainties together with an adaptive dead-zone compensation scheme. The hydraulic actuator is modeled as a forth order nonlinear system including the valve dynamic as a first order linear system and considering a valve with a dead-...

[1] Prediction of flow through variably saturated porous media requires accurate knowledge of the soil hydraulic properties, namely the water retention function (WRF) and the hydraulic conductivity function (HCF). Unfortunately, direct measurement of the HCF is time consuming and expensive. In this study, we derive a simple closed-form equation that predicts the saturated hydraulic conductivity...

Robustness and fault-tolerance are desirable properties for hydraulic working machines and field robots. In applications where service personnel do not have easy access to the machine, it is important that the machine can continue its operation despite single machinery faults. Digital hydraulics enables a design which is inherently fault-tolerant by having each hydraulic actuator controlled by ...

Hydraulic fracturing in the fractured reservoirs plays a significant impact on the production rate. In this study, the hydrostatic condition is taken into account, the hydraulic fracturing operation was applied in every direction usinga written distinct element code. In each direction the hydraulic fracture is applied with different lengths and in each level the amount of production is predicte...