Topic
Hydraulic machinery
About: Hydraulic machinery is a research topic. Over the lifetime, 34190 publications have been published within this topic receiving 153453 citations. The topic is also known as: hydraulic equipment & fluid energy machine.
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11 Dec 1998TL;DR: In this paper, an actively controlled rotary steerable drilling system for directional drilling of wells, the system having a rotary drive component rotatable within a tubular sliding tool collar that incorporates elastic anti-rotation members to maintain a coupled relation with the borehole wall during drilling.
Abstract: An actively controlled rotary steerable drilling system for directional drilling of wells, the system having a rotary drive component rotatable within a tubular sliding tool collar that incorporates elastic anti-rotation members to maintain a coupled relation with the borehole wall during drilling. An offsetting mandrel is supported within the tool collar by a knuckle joint for pivotal movement and for rotation relative to the tool collar and has a lower end extending from the tool collar and supporting a drill bit. To achieve controlled steering of the rotating drill bit, orientation of the tool collar is sensed and the offsetting mandrel is maintained geostationary and selectively axially inclined relative to the tool collar by orienting it about the knuckle joint. An alternator and a hydraulic pump, located within the tool collar, are driven by relative rotation of the rotary drive component with the tool collar to produce electric power and hydraulic pressure for the electronics package of the tool and for actuation of hydraulic system components. Hydraulic cylinder and piston assemblies, actuated by tool position signal responsive solenoid valves, control the angular position of the offsetting mandrel with respect to the tool collar. The hydraulic pistons are servo-controlled responsive to signal input from tool position sensing systems such as magnetometers and accelerometers which provide real-time position signals to the hydraulic control system.
213 citations
07 Nov 2002
TL;DR: In this paper, a linear permanent magnet synchronous machine is compared to the transverse flux machine in a basic design study for a wave energy converter, and the latter machine is identified as offering the best potential.
Abstract: Wave power devices traditionally use conventional rotary electrical machines for power conversion. However hydraulic systems or air turbines are required to convert the low reciprocating motion of the wave device to rotation at 1500 rpm. The concept of a direct drive system is introduced, in which a reciprocating electrical machine is driven at the same speed as the device. A linear permanent magnet synchronous machine is compared to the transverse flux machine in a basic design study for this application. The latter machine is identified as offering the best potential. Electromagnetic and electric circuit models are developed to investigate the performance of the transverse flux machine in a wave energy converter. Measures are suggested to optimise the performance of the machine.
207 citations
TL;DR: In this article, the optimal command theory was used to determine the control law of the bypass valve of a wave energy converter. And the authors showed that declutching control can lead to energy absorption performance at least equivalent to that of pseudo-continuous control.
205 citations
TL;DR: In this article, a grey prediction model combined with a fuzzy PID controller is proposed to improve the control quality of the loading system while eliminating or reducing the disturbance, and fuzzy controllers and a tuning algorithm are used to change the grey step size in order to improve control quality.
199 citations