A Novel Piezoelectric Double-Flapper Servovalve Pilot Stage: Operating Principle and Performance Prediction

2018 ◽  
Author(s):  
Paolo Tamburrano ◽  
Riccardo Amirante ◽  
Elia Distaso ◽  
Andrew R. Plummer
Keyword(s):  
Dynamic Response ◽  
Performance Prediction ◽  
Response Speed ◽  
Differential Pressure ◽  
High Response ◽  
Main Stage ◽  
Two Stage ◽  
Positioning Accuracy ◽  
And Performance ◽  
Speed And Accuracy

This paper proposes a novel architecture for the pilot stage of electro-hydraulic two-stage servovalves that does not need a quiescent flow and a torque motor as well as a flexure tube to operate. The architecture consists of two small piezoelectric valves, coupled with two fixed orifices, which allow variation of the differential pressure at the main stage spool extremities in order to move it with high response speed and accuracy. Each piezoelectric valve is actuated by a piezoelectric ring bender, which exhibits much greater displacement than a stack actuator of the same mass, and greater force than a rectangular bender. The concept is intended to reduce the influence of piezoelectric hysteresis. In order to assess the validity of the proposed configuration and its controller in terms of spool positioning accuracy and dynamic response, detailed simulations are performed by using the software Simscape Fluids. At 50% amplitude the −90° bandwidth is about 150Hz.

scholarly journals A Novel Servovalve Pilot Stage Actuated by a Piezo-Electric Ring Bender (Part II): Design Model and Full Simulation

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2267 ◽  
Author(s):  
Paolo Tamburrano ◽  
Andrew R. Plummer ◽  
Pietro De Palma ◽  
Elia Distaso ◽  
Riccardo Amirante
Keyword(s):  
Numerical Model ◽  
Design Procedure ◽  
Response Speed ◽  
Low Complexity ◽  
Design Tool ◽  
Geometrical Parameters ◽  
Main Stage ◽  
Neutral Position ◽  
Two Stage ◽  
Spool Valve

In part I of this study, we experimentally and numerically investigated the pilot stage of a novel two-stage servovalve architecture. The novelty of the proposed configuration is the torque motor being removed and replaced with two small two-way two-position (2/2) valves actuated by piezoelectric ring benders, which can effectively control the opening degree of a main spool valve. With this novel architecture, the typical drawbacks of two-stage servovalves can be overcome, such as the high complexity of the torque motor and the high internal leakage in the pilot stage when the main valve is at rest in the neutral position (null). The low complexity and the negligible internal leakage of the piezo-valves are accompanied by the high response speed typical of piezoelectric actuators. The valve assessment is completed in the present study, since the entire valve architecture (main stage + pilot stage) is investigated. In particular, a simplified numerical model is developed to provide a design tool that allows, for a given main stage spool, the values of the geometrical parameters of the pilot stage to be chosen along with the characteristics of the ring bender. This design procedure is applied to a 7 mm diameter main spool; afterward, a detailed numerical model of the entire valve, solved by SimScape Fluids software, is employed to demonstrate that the response of the main stage valve is very rapid while ensuring negligible internal leakage through the piezo-valves when the main stage is closed (resulting in lower power consumption). For this reason, the proposed valve can be regarded as a “clean” component for energy conversion, having lower energy consumption than commercially available servovalves.

An Enhanced Two Stage MMSE Equalizer for Coded FBMC/OQAM Systems

2019 ◽  
Vol 10 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Mohammad Rizk Assaf ◽  
Abdel-Nasser Assimi
Keyword(s):  
Error Propagation ◽  
Channel Model ◽  
Error Correcting Codes ◽  
Two Stage ◽  
Probability Of Error ◽  
Second Stage ◽  
Different Types ◽  
Mmse Equalizer ◽  
And Performance ◽  
Ici Cancellation

In this article, the authors investigate the enhanced two stage MMSE (TS-MMSE) equalizer in bit-interleaved coded FBMC/OQAM system which gives a tradeoff between complexity and performance, since error correcting codes limits error propagation, so this allows the equalizer to remove not only ICI but also ISI in the second stage. The proposed equalizer has shown less design complexity compared to the other MMSE equalizers. The obtained results show that the probability of error is improved where SNR gain reaches 2 dB measured at BER compared with ICI cancellation for different types of modulation schemes and ITU Vehicular B channel model. Some simulation results are provided to illustrate the effectiveness of the proposed equalizer.

Experimental and computer aided solubility quantification of diverse lignins and performance prediction

2021 ◽  
Vol 57 (14) ◽  
pp. 1782-1785
Author(s):  
Olumoye Ajao ◽  
Marzouk Benali ◽  
Naïma El Mehdi
Keyword(s):  
Performance Prediction ◽  
Solvent Fractionation ◽  
Computer Aided ◽  
And Performance

New insights on the variability of solubility elucidated for diverse lignins, quantification thereby makes it possible to predict performance for solvent fractionation processes and polymers formulation.

Effect of main-stage filter media selection on the loading performance of a two-stage filtration system

2021 ◽  
Vol 195 ◽  
pp. 107745
Author(s):  
Xinjiao Tian ◽  
Qisheng Ou ◽  
Chenxing Pei ◽  
Zhenming Li ◽  
Jingxian Liu ◽  
...  
Keyword(s):  
Media Selection ◽  
Main Stage ◽  
Filter Media ◽  
Two Stage ◽  
Filtration System
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