Development of a proportional poppet-type water hydraulic valve

2009 ◽  
Vol 223 (9) ◽  
pp. 2099-2107 ◽  
Author(s):  
S-H Park
Keyword(s):  
Dynamic Characteristics ◽  
Pulse Width ◽  
Simple Structure ◽  
Pulse Width Modulation ◽  
Tap Water ◽  
Environmental Problems ◽  
Hydraulic Systems ◽  
Water Hydraulic ◽  
Type Water ◽  
Hydraulic Valve

To address the environmental problems and the safety of hydraulic systems, the development of novel water hydraulic systems using working fluids such as tap water are being developed successfully. In this study, we aim to develop a proportional water hydraulic valve using a proportional poppet as the main valve, which has an on—off function as well as a proportional function. The proposed proportional poppet-type water hydraulic valve has a simple structure with a control orifice that passes to the pilot orifice at both sides of the conventional poppet. Experiments verified that the relation between the main flowrate and pilot flowrate of the developed valve is linear and that the dynamic characteristics of the proportional poppet are satisfactory. Also, the developed valve was verified to be suitable for pulse width modulation (PWM) control and practical use for the control of water hydraulic systems.

Microbial water quality and diversity in hydraulic systems using tap water as a pressure medium

2000 ◽  
Vol 41 (12) ◽  
pp. 215-222 ◽  
Author(s):  
S. M. Soini ◽  
K. T. Koskinen ◽  
M. Vilenius ◽  
J. A. Puhakka
Keyword(s):  
Hydraulic System ◽  
Tap Water ◽  
Pilot Scale ◽  
Hydraulic Systems ◽  
Water Hydraulics ◽  
Pressure Medium ◽  
Viable Bacteria ◽  
Water Hydraulic ◽  
Cell Densities

Water hydraulics uses tap water or demineralised water as a pressure medium and has fewer environmental impacts than oil-using hydraulics. The applicability is restricted by the microbial quality of the medium. The objectives of this study were to determine whether microbes grow in the pressure medium of a water hydraulic system, biofilm is formed on the surfaces and to describe the diversity of bacteria that survive and grow in water hydraulic systems. A pilot-scale water hydraulic system was used in the experiments. The viable counts in the pressure medium increased in three days from 102 to 3 ×104 cfu/ml followed by a gradual decrease towards the steady-state concentration of 6× 1034 cfu/ml. The total cell numbers decreased from 3×105 to 2 ×104 cells/ml during the three weeks of operation indicating attachment onto the system surfaces as biofilms. The biofilm cell densities on collector slide surfaces varied between 7 ×103 and 1.2 ×104 cells/cm2 after 21 days of operation. The phosphatase activity in the pressure medium was in conformity with the numbers of viable bacteria. The enzymatic activities (α- and β- glucosidase, phosphatase, aminopeptidase) varied between 0.4 and 300 nmol/lh. The diversity of bacteria growing in the system was wide and differed from that of tap water.

Study on a Pneumatic Artificial Muscle Actuator

2013 ◽  
Vol 860-863 ◽  
pp. 2738-2741
Author(s):  
Lian Zhi Yu
Keyword(s):  
Control System ◽  
Dynamic Characteristics ◽  
Mechanical Model ◽  
Pulse Width ◽  
High Speed ◽  
Pulse Width Modulation ◽  
Artificial Muscle ◽  
High Accuracy ◽  
Pneumatic Artificial Muscle ◽  
Micro Robot

Pneumatic artificial actuator had been designed and was used as power driven. A 3-DOF Pneumatic artificial actuator was described as a micro-robot flexible actuator, the mechanical model and dynamic characteristics were studied for high accurate control. The control system was designed and the actuator characteristics were tested in experiments. Results prove the pneumatic artificial actuator has good performances and can be controlled in high speed and high accuracy by computer system with PWM (Pulse Width Modulation: PWM).

Design, Modeling, and Validation of a High-Speed Rotary Pulse-Width-Modulation On/Off Hydraulic Valve

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Haink C. Tu ◽  
Michael B. Rannow ◽  
Meng Wang ◽  
Perry Y. Li ◽  
Thomas R. Chase ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Pulse Width ◽  
High Speed ◽  
Pulse Width Modulation ◽  
Hydraulic Systems ◽  
Rotary Valve ◽  
Output Pressure ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Actuation Power

Efficient high-speed on/off valves are an enabling technology for applying digital control techniques such as pulse-width-modulation (PWM) to hydraulic systems. Virtually variable displacement pumps (VVDPs) are one application where variable displacement functionality is attained using a fixed-displacement pump paired with an on/off valve and an accumulator. High-speed valves increase system bandwidth and reduce output pressure ripple by enabling higher switching frequencies. In addition to fast switching, on/off valves should also have small pressure drop and low actuation power to be effective in these applications. In this paper, a new unidirectional rotary valve designed for PWM is proposed. The valve is unique in utilizing the hydraulic fluid flowing through it as a power source for rotation. An unoptimized prototype capable of high flow rate (40 lpm), high speed (2.8 ms transition time at 100 Hz PWM frequency), and low pressure drop (0.62 MPa), while consuming little actuation power (<0.5% full power or 30 W, scavenged from fluid stream), has been constructed and experimentally validated. This paper describes the valve design, analyzes its performance and losses, and develops mathematical models that can be used for design and simulation. The models are validated using experimental data from a proof-of-concept prototype. The valve efficiency is quantified and suggestions for improving the efficiency in future valves are provided.

The 1-Bit Instrument

2020 ◽  
Vol 1 (1) ◽  
pp. 44-74
Author(s):  
Blake Troise
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Interleaving Techniques ◽  
Sonic Environment

The 1-bit sonic environment (perhaps most famously musically employed on the ZX Spectrum) is defined by extreme limitation. Yet, belying these restrictions, there is a surprisingly expressive instrumental versatility. This article explores the theory behind the primary, idiosyncratically 1-bit techniques available to the composer-programmer, those that are essential when designing “instruments” in 1-bit environments. These techniques include pulse width modulation for timbral manipulation and means of generating virtual polyphony in software, such as the pin pulse and pulse interleaving techniques. These methodologies are considered in respect to their compositional implications and instrumental applications.

An Equivalent Circuit Model for Vertical Comb Drive MEMS Optical Scanner Controlled by Pulse Width Modulation

2012 ◽  
Vol 132 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Satoshi Maruyama ◽  
Muneki Nakada ◽  
Makoto Mita ◽  
Takuya Takahashi ◽  
Hiroyuki Fujita ◽  
...  
Keyword(s):  
Equivalent Circuit ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Comb Drive ◽  
Optical Scanner
Sign in / Sign up

Export Citation Format

Share Document