Nozzle Flow Rate, Pressure Drop, and Response Time of Pulse Width Modulation (PWM) Nozzle Control Systems

2021 ◽  
Vol 64 (5) ◽  
pp. 1519-1532
Author(s):  
Jonathan Fabula ◽  
Ajay Sharda ◽  
Qing Kang ◽  
Daniel Flippo
Keyword(s):  
Pressure Drop ◽  
Response Time ◽  
Control Systems ◽  
Flow Rate ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Application Rate ◽  
Application Rates ◽  
Duty Cycles ◽  
Nozzle Pressure

HighlightsNozzle pressure drop varies between PWM systems at different application rates and application pressures.Change in flow rate with respect to the expected flow differs between PWM systems at different rates and pressures.There was a latency before the system reached the target application pressure.PWM systems operate for less time than the specified duty cycle, which may cause application errors.Abstract. Three PWM nozzle control systems, Capstan PinPoint II, John Deere ExactApply, and Raven Hawkeye, referred to as systems S1, S2, and S3, respectively, were used in this study. Data on nozzle pressure, boom pressure, flow rate, and response time were recorded with different duty cycles (25%, 50%, 75%, and 100%) and operating frequencies (10, 15, and 30 Hz) for two application rates (112.2 and 187.1 L ha-1) and two application pressures (275.8 and 448.2 kPa) at 1 kHz using a LabVIEW program and a cRIO data acquisition system. Results indicated that the PWM systems perform differently when operating at different application rates, pressures, duty cycles, and frequencies. Each PWM system provided a different pressure drop at the nozzle during operation. The increase in application rate and pressure increased the pressure drop. The percent change in flow rate with respect to the expected flow was also significantly different between the PWM systems, which could be due to the differences in pressure provided at the nozzle during operation. The PWM systems also showed latency before reaching the target application pressure during operation and operated for less time than the specified duty cycle at stable target pressure while also continuing to spray even after the solenoid valves had closed. The application pressure during peak and fall times and the time of stable application pressure within a cycle should be given careful consideration when selecting a PWM system, as they can contribute to application errors. Producers should also consider the pressure drop with the selected PWM system and target application rate to set up the system to apply at the desired pressure. Manufacturers mostly recommend operating PWM systems at 10 Hz. For the purpose of this study, the operating frequency of the PWM systems was set to 10 and 15 Hz for S1, to 15 and 30 Hz for S2, and to 10, 15, and 30 Hz for S3. Producers should expect differences in pressure drop, stabilized pressure application time, and flow rate if they choose to operate at a higher frequency. The results of this study are only applicable to the types of nozzle bodies and nozzle tips used. The data will differ based on the dual-orifice valve coefficient equation: the larger the second orifice, the greater the pressure drop. This will affect the final orifice pressure, as well as the flow rate. This study did not address the impact of flow resistance caused by differences in the design of nozzle bodies and nozzle types. Keywords: Nozzle flow rate, Pressure drop, Pulse width modulation control modules, Response time.

FLOW CHARACTERISTICS OF A LIQUID CRYSTAL MIXTURE IN A CIRCULAR PIPE ELECTRODE

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1346-1352
Author(s):  
TETSUHIRO TSUKIJI ◽  
EITARO KOYABU
Keyword(s):  
Liquid Crystal ◽  
Pressure Drop ◽  
Electric Fields ◽  
Flow Rate ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Flow Direction ◽  
Flow Analysis ◽  
Circular Pipe ◽  
Crystal Mixture

A circular pipe electrode was developed to control the pressure and the flow rate of the ER(Electro-rheological) fluids by one of the authors. The shape of the electrode is a circular pipe and some parts of the inner surface of the pipe are the electrode. The diameter of the tube is 1mm and the four pairs of the electrode are used. In the present study a liquid crystal mixture is selected for a homogeneous ER fluid and the pressure drop of the circular pipe electrode is measured for the constant flow rates under application of the voltages. The voltages are added in the peripheral direction. The director which is the average direction of the molecular of the liquid crystal is perpendicular to the flow direction. On the other hands, numerical analysis of the electric fields and the flow in the circular pipe electrode is conducted and the relations between the flow rate and the pressure are obtained for various electric field intensities, which almost agree with experimental results. The emphasized point of the present flow analysis is assuming that the viscosity of a liquid crystal mixture distributes in the flow field. Furthermore the pulse-wave voltages are added to the electrodes to control the pressure drop using the pulse width modulation. It is found that the pressure can be controlled using the pulse width modulation in the some range of the parameters.

scholarly journals Evaluation of spray pattern uniformity using three unique analyses as impacted by nozzle, pressure, and pulse‐width modulation duty cycle

2019 ◽  
Vol 75 (7) ◽  
pp. 1875-1886 ◽  
Author(s):  
Thomas R Butts ◽  
Joe D Luck ◽  
Bradley K Fritz ◽  
W Clint Hoffmann ◽  
Greg R Kruger
Keyword(s):  
Duty Cycle ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Spray Pattern ◽  
Nozzle Pressure

scholarly journals Modeling and analysis of vector control systems for asynchronous motor

2020 ◽  
Vol 178 ◽  
pp. 01001 ◽  
Author(s):  
Viktor Meshcheryakov ◽  
Tatyana Sinyukova ◽  
Alexey Sinyukov ◽  
Andrei Boikov ◽  
Rustem Mukhametzhanov
Keyword(s):  
Vector Control ◽  
Control Systems ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Asynchronous Motor ◽  
Evaluation Criteria ◽  
Torque Ripple ◽  
Modulation Method ◽  
Asynchronous Electric Drive ◽  
Vector Systems

The study aims at the analysis of vector control asynchronous electric drive systems. For comparison and evaluation, mathematical models of systems are implemented in the environment of simulation modeling Matlab Simulink. The evaluation criteria selected were: complexity of implementation, energy efficiency of the inverter, accuracy of speed maintenance, torque ripple, reaction speed of the system to disturbances from the side of the drive mechanism, impact on the supply network. Vector control systems by ensuring the maintenance of accuracy of the moment in the entire range of speed control are more widespread. The study of vector systems, the formation of the stator voltage vector in which is carried out using pulse-width modulation. The signal organization during the study was carried out by several methods. At the initial stage, the signal was formed due to relay-vector control in a closed loop for monitoring the instantaneous values of current errors without forced modulation; at the next stage of the study, the signal was generated using sinusoidal pulse-width modulation based on a comparison of control signals with some reference vector, the final stage became a spatial-vector modulation method.

Sequential Control of Multichannel On–Off Valves for Linear Flow Characteristics Via Averaging Pulse Width Modulation Without Flow Meter: An Application for Pneumatic Valves

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Kanchit Pawananont ◽  
Thananchai Leephakpreeda
Keyword(s):  
Flow Rate ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Single Channel ◽  
Flow Characteristics ◽  
Volumetric Flow Rate ◽  
Operating Conditions ◽  
Mean Flow ◽  
Flow Meter ◽  
Linear Flow

Control of on–off valves for linear flow characteristics is a challenging design problem due to nonlinearity of valve mechanism and fluidic properties under various operating conditions. In this study, averaging pulse width modulation (PWM) is proposed as a control valve signal by implementing PWM with predetermined duty period so that overflow at the open position and underflow at the closed position are divided proportionately around desired mean flow rates during entire cycle periods. Multichannels in a parallel pattern are implemented to yield linear flow characteristics with higher resolution than a single channel. With pressure and temperature measurements, the volumetric flow rate is determined by an empirical model of flow characteristics across flow control valves at given operating conditions. The experimental results on achieving the desired volumetric flow rate of air under actual flow conditions without a flow meter are presented for viability of the proposed methodology in practical uses.

scholarly journals Machine ability on Leather using Co2 Laser and Power Diode Laser

2019 ◽  
Vol 8 (5S3) ◽  
pp. 151-154
Keyword(s):  
Laser Beam ◽  
Laser Diode ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Laser Diodes ◽  
Machining Process ◽  
Laser Beam Machining ◽  
Laser Technology ◽  
Duty Cycles ◽  
Power Diode

Leather is a versatile, robust and trendy material and therefore its applications are nearly endless. The conventional method of leather cutting takes a lot of man power. Power diode-based Laser technology has grown significantly during recent years due to numerous advantages over conventional cutting methods. The conventional Lasers also have some drawbacks in cutting such as Geometrical inaccuracies, Carbonization, Overcut etc. This can be reduced by the use of Laser diodes. The main purpose of using Laser diode is to reduce power consumption. In the present study, an attempt has been made to develop laser diode-based Laser beam machining (LBM) and CO2 based LBM, to compare the performance measures of Carbonization and Geometrical inaccuracy. The main objective of this work is to enhance the machining process using Laser diode, to make it eco-friendly through the different duty cycles of Pulse Width Modulation (PWM) which can be used to control the intensity of the Laser beam

scholarly journals Water distribuition characteristics and soil loss of LEPA Quad-Spray emitter nozzles

2013 ◽  
Vol 33 (2) ◽  
pp. 223-236 ◽  
Author(s):  
Moises S. Ribeiro ◽  
Luiz A. Lima ◽  
Alberto Colombo ◽  
Ana C. D. M. Caldeira ◽  
Fabio H. de S. Faria
Keyword(s):  
Flow Rate ◽  
Soil Loss ◽  
Water Distribution ◽  
Weighted Average ◽  
Application Rate ◽  
Nozzle Diameter ◽  
Water Application ◽  
Application Rates ◽  
Average Water ◽  
Pattern Width

The objective of this study was to characterize water application rate, water application pattern width, flow rate, water distribution uniformity and soil loss caused by nozzles of the Low Energy Precision Aplication (LEPA) type Quad-Spray emitter. The study was carried out at the Hydraulic and Irrigation Laboratory of the Department of Engineering at the Federal University of Lavras, in Lavras, state of Minas Gerais - MG, Brazil. Twenty-two (22) LEPA Quad-Spray emitter nozzles were evaluated, with nozzle diameter ranging from 1.59 to 9.92 mm. The experimental design used was entirely randomized, with three replications.Increasing values of nozzle flow rate ranging from 77.44 up to 3,044 L h-1, were obtained with increasing nozzle diameter sizes. Application pattern width ranged from 0.56 up to 3.24m, according to nozzles diameter size. Low values of CDU (maximum of 35.73%) were observed when using the Quad-Spray nozzles. Observed average water application rates covered the range between 68.05 mm h-1 (the lowest value that was obtained with the 2.38mm nozzle) and 258.15 mm h-1 (the highest value that was observed with the 9.92 mm). Average water application rates increased in a simple non-linear function with the increase of nozzle size diameter. However, the weighted average increase in the amount of soil loss by erosion was not related to the increase of weighted average water application values.

RELIABILITY TESTS OF PULSE WIDTH MODULATION (PWM) VALVES FOR FLOW RATE CONTROL OF ANHYDROUS AMMONIA

2005 ◽  
Vol 21 (6) ◽  
pp. 955-960 ◽  
Author(s):  
G. C. Bora ◽  
M. D. Schrock ◽  
D. L. Oard ◽  
J. J. Grimm ◽  
T. C. Kolb ◽  
...  
Keyword(s):  
Flow Rate ◽  
Rate Control ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Anhydrous Ammonia ◽  
Flow Rate Control

scholarly journals Distributed Control

1999 ◽  
Vol 121 (01) ◽  
pp. 68-69
Author(s):  
Daryl Prince
Keyword(s):  
Control Systems ◽  
Motion Control ◽  
Distributed Control ◽  
Pulse Width ◽  
High Speed ◽  
Pulse Width Modulation ◽  
Current Control ◽  
Analog Output

This article discusses servo motion systems, which are motion control systems that combine hardware and software, have innumerable applications in compact modules. Some motion controllers operate on multiple platforms and buses, with units providing analog output to a conventional amplifier, as well as units that provide current control and direct pulse width modulation (PWM) output for as many as 32 motors simultaneously. There are amplifiers that still require potentiometers to be adjusted for the digital drives’ position, velocity, and current control. All major value-adding components of motion control systems will soon have to comply with the demands for faster controllers with high-speed multi axis capabilities supplying commands in multitasking applications.

Sign in / Sign up

Export Citation Format

Share Document