Hydraulic systems are widely used in manufacturing processes and transportation systems where energy intensive operations are performed and “machine” control is vital. A variety of ßow control products exist including manual directional control valves, proportional directional control valves, and servo-valves. The selection of a control valve actuation strategy is dependent on the system respon...

Electro-hydraulic proportional control valves are widely applied for motion control in the electro-hydraulic fluid power system. Normally, a sliding spool is used in the proportional control valve to control the flow direction and flow rate passing through the valve, as a result, the meterin and meter-out orifices are mechanically connected [1]. The sliding spool makes the system robust and eas...

Energy storage devices for fluid power applications that are significantly more compact than existing ones will enable energy regeneration for many applications, including fluid power hybrid vehicles and construction equipment. The current approach to hydraulic energy storage makes use of a compressed gas enclosed in a closed chamber. As the system must contain the expanded gas and the hydrauli...

In this study, a new-generation subsurface upflow wetland (SUW) system packed with the unique sorption media was introduced for nutrient removal. To explore the interface between hydraulic and environmental performance, a tracer study was carried out in concert with a transport model to collectively provide hydraulic retention time (7.1 days) and compelling evidence of pollutant fate and transp...

Fluid power actuators are characterized by their high-power density and excellent dynamic response. They are ideally suited to many high dynamic applications in modern machine tools. However, the disadvantages of hydraulic systems such as nonlinear dynamic behaviour due to friction, fluid compressibility need to be overcome. This is successfully obtainable only by implementation of modern digit...

Robotic devices are traditionally actuated by hydraulic systems or electric motors. However, with the desire to make robotic systems more compact and versatile, new actuator technologies are required. In this paper, the control of ionic polymer metal composite actuators is investigated from a practical perspective. The actuator characteristics are examined though the unblocked maximum displacem...

This paper deals with the optimal control problem that arise when a hydraulic system with fixed-head hydroplants is considered. In the frame of a deregulated electricity market the resulting Hamiltonian for such systems is linear in the control variable and results in an optimal singular/bang-bang control policy. To avoid difficulties associated with the computation of optimal singular/bang-ban...

This paper presents how a hydraulic system can be properly modeled for hydraulic balancing, knowledge of flow distribution, coupled simulation, and evaluation of control, etc. It focuses on water-based heating and cooling systems, which generally have high energy efficiency in design but could perform poorly in reality due to the undersensing condition and strong thermal-hydraulic coupling. The...

Model-based controllers have successfully been applied to many electrically driven robotic manipulators to improve their tracking performance. The application to hydraulically actuated systems however is not straight forward, due to the nonlinear internal dynamics of the actuators. This paper presents the modelling of an experimental hydraulic robot arm and the implementation of a cascaded cont...