scholarly journals A New Control Method for Backlash Error Elimination of Pneumatic Control Valve

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1378
Author(s):  
Haiming Xu ◽  
Yong Li ◽  
Lanzhu Zhang
Keyword(s):  
Physical Model ◽  
Control Method ◽  
Control Valve ◽  
Experimental Result ◽  
Pneumatic Control ◽  
Valve System ◽  
Electromagnetic Model ◽  
Error Elimination ◽  
Calculation Results ◽  
Backlash Error

Backlash is a commonly non-linear phenomenon, which can directly degrade the control accuracy of a pneumatic control valve. To explain the cause and law of backlash error, and to propose an effective method, many research works on the modeling of a pneumatic control valve system have been carried out. The currently model of a control valve system can be classified as a physical model, data-driven model, and semi-physical model. However, most models only consider the force-displacement conversion process of a pneumatic diagram actuator in a pneumatic control valve system. A physical model based on the whole workflow of the pneumatic control valve system is established and a control method to eliminate the backlash error is proposed in this paper. Firstly, the physical model of the pneumatic control valve system is established, which is composed of three parts: pneumatic diaphragm actuator model, nozzle-flapper structure model and electromagnetic model. After that, the input–output relationship of the pneumatic control valve system can be calculated according to the established physical model, and the calculation results are consistent with the experimental result. Lastly, a self-calibration PID (SC-PID) control method is proposed for backlash error elimination. The proposed method can solve valve stem oscillation caused by backlash during valve control.

Progress of the 40 MW-Class Advanced Humid Air Turbine Tests

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Manabu Yagi ◽  
Hidefumi Araki ◽  
Hisato Tagawa ◽  
Tomomi Koganezawa ◽  
Chihiro Myoren ◽  
...  
Keyword(s):  
Metal Surface ◽  
Control Method ◽  
Cooling System ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Test Facility ◽  
Humid Air ◽  
Air Turbine ◽  
Calculation Results ◽  
Flow Compressor

A 40 MW-class test facility has been constructed to verify practicability of applying the advanced humid air turbine (AHAT) system to a heavy-duty gas turbine. Verification tests have been carried out from January 2012, and interaction effects between the key components were established. First, water atomization cooling (WAC) was confirmed to contribute to both increased mass flow rate and pressure ratio for the axial-flow compressor. The good agreement between measured and calculated temperatures at the compressor discharge was also confirmed. These results demonstrated the accuracy of the developed prediction model for the WAC. Second, a control method that realized both flame stability and low nitrogen oxides (NOx) emissions was verified. Although the power output and air humidity were lower than the rated values, NOx concentration was about 10 ppm. Finally, a hybrid nozzle cooling system, which utilized both compressor discharged air and humid air, was developed and tested. The metal surface temperatures of the first stage nozzles were measured, and they were kept under the permissible metal temperature. The measured temperatures on the metal surface reasonably corresponded with calculation results.

Experimental Investigation on Pressure Drop in Corrugated Pipes

2013 ◽  
Author(s):  
Hojin Ahn ◽  
Ibrahim Uslu
Keyword(s):  
Pressure Drop ◽  
Friction Factor ◽  
Cross Section ◽  
Circular Cross Section ◽  
Control Valve ◽  
Experimental Result ◽  
Helical Coil ◽  
Solar Panels ◽  
Steel Pipes ◽  
Friction Factors

The characteristics of pressure drop in corrugated pipes were experimentally studied in both straight and helically coiled configurations. The present study employed the stainless-steel pipes with the corrugation of circular cross section, which are widely used in boilers and pipe systems between solar panels and boilers. The diameters of corrugated pipes were 20.4, 25.4, 34.5 and 40.5 mm. The corrugated pipe, approximately 10 m in length, was configured either in the straight manner or in the helical coil with the helix diameter of 0.43 or 0.64 m. Water stored in a tank was fed into a corrugated pipe by a pump while the flow rate was controlled by a control valve. The friction factors of the pipes remain constant over the range of Reynolds number from 4,000 to 50,000, indicating that the flow in the pipe was fully turbulent. When the pipe was straightly configured, the friction factors were measured to be 0.070, 0.075, 0.12 and 0.22 for the diameter of 20.4, 25.4, 34.5 and 40.5 mm, respectively. Thus the present study showed that the friction factors increased with the increasing diameter of the pipe. This result is clearly contrary to a rare experimental result available in the literature. On the other hand, as expected, the friction factor for the helically coiled configuration was higher than that of the straight configuration with the same tube diameter, and the configuration of the smaller helix diameter yielded the larger friction factor. The reason for the increasing friction factor with the increasing pipe diameter remains to be explored further.

scholarly journals Stem Control of a Sliding-Stem Pneumatic Control Valve Using a Recurrent Neural Network

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mohammad Heidari ◽  
Hadi Homaei
Keyword(s):  
Neural Network ◽  
Recurrent Neural Network ◽  
Neural Control ◽  
Closed Loop ◽  
Control Valve ◽  
Superior Performance ◽  
Pneumatic Control ◽  
Response Characteristics ◽  
Control Scheme ◽  
Simulation Results

This paper presents a neural scheme for controlling an actuator of pneumatic control valve system. Bondgraph method has been used to model the actuator of control valve, in order to compare the response characteristics of valve. The proposed controller is such that the system is always operating in a closed loop, which should lead to better performance characteristics. For comparison, minimum- and full-order observer controllers are also utilized to control the actuator of pneumatic control valve. Simulation results give superior performance of the proposed neural control scheme.

The Design of Two-Way Control System of Master-Slave Medical Robot and its Digital Operation Experiment Research

2011 ◽  
Vol 197-198 ◽  
pp. 203-207
Author(s):  
Shi Jie Li ◽  
Ya Rui Zhang ◽  
Hai Xia Bi ◽  
Tie Cheng Wang
Keyword(s):  
Experimental Study ◽  
Control System ◽  
Robot Control ◽  
Control Method ◽  
Organization Design ◽  
Simulation System ◽  
Simulation Software ◽  
Experimental Result ◽  
Experiment Research ◽  
Medical Robot

In recent years, the research on the medical robot's already became a new domain about the robot application, particularly the special medical robot already became a direction of the medical robot develops. This article started with the medical robot organization design, construct the three-dimensionalmodel,designed master-Slave Medical robot control system overall project, determined a new two-way control method of force telepresence, developed Master-Slave medical robot control system's simulation software, and conducted the experimental study, the experimental result showed that this simulation system had the very good timeliness and the accuracy.

scholarly journals A software and hardware design scheme of intelligent valve positioner

2021 ◽  
Vol 268 ◽  
pp. 01067
Author(s):  
Haiming Xu ◽  
Lanzhu Zhang
Keyword(s):  
Pid Control ◽  
Control Algorithm ◽  
Hardware Design ◽  
Control Process ◽  
Control Valve ◽  
Pneumatic Control ◽  
Design Scheme ◽  
Valve Stem ◽  
Software And Hardware ◽  
Better Than

Valve positioner is the core component of the pneumatic control valve. A new software and hardware design scheme of intelligent valve positioner is presented in this paper. The circuit composition of each part of the intelligent valve positioner is introduced in hardware part. Based on it, a hardware solution to realize HART ‘multi-point’ communication is proposed in this research. In the software design, a novel combined PID control algorithm is proposed to solve the nonlinear problem caused by the friction between the valve stem and the packing during the control process. Simulation results show that the method proposed in this paper is better than traditional PID method and fuzzy PID method. The software and hardware design scheme of the valve positioner proposed in this paper has certain guiding significance for the development of related products.

scholarly journals Design and Development of Experimental Based Phase Modulated Model Predictive Control for Torque Ripple Reduction of MMC Fed BLDC Motor

2021 ◽  
Author(s):  
Rahul Jaiswal ◽  
◽  
Anshul Agarwal ◽  
Richa Negi ◽  
Abhishek Vikram ◽  
...  
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Control Method ◽  
Torque Ripple ◽  
Current Control ◽  
Experimental Result ◽  
Control Technique ◽  
Switching Frequency ◽  
Bldc Motor ◽  
Brushless Dc

This article represents the torque ripple performance of modular multilevel converter (MMC) fed brushless dc (BLDC) motor using different current control technique. For reducing the ripple current in BLDC motor, a phase-modulated model predictive control (PMMPC) technique has been proposed. The stator ripple current is almost negligible using PMMPC. This PMMPC current control method is a significant minimization of torque ripple in BLDC motor. A comparative torque ripple behaviour of MMC fed BLDC motor has been done using phase-modulated model predictive control, model predictive control (MPC) and proportional integral (PI) control at different switching frequency. It has been observed that a PMMPC current control technique is more efficient as compared to the MPC as well as PI current control technique. It has also been observed that the torque ripple performance is improved while using PMMPC as compared to the MPC and PI controller. Simulation results have been verified with the help of experimental result and these results are obtained in good agreement to the simulated results.

scholarly journals Dynamic Pressure Test and Analysis of Marine Ballasted Centrifugal Pump under Rapid Changing Conditions

2021 ◽  
Vol 9 (11) ◽  
pp. 1299
Author(s):  
Zhipeng Zhu ◽  
Houlin Liu
Keyword(s):  
Flow Rate ◽  
Pressure Pulsation ◽  
Dynamic Pressure ◽  
Control Valve ◽  
Rate Reduction ◽  
Harmonic Frequency ◽  
Rapid Reduction ◽  
Transient Conditions ◽  
Pneumatic Control ◽  
Increasing Trends

Ship ballast pumps have stringent requirements for their transient characteristics. Here, the pneumatic control valve and programmable logic controller (PLC) are applied to realize the rapid reduction in flow rate for ballast pumps, and the dynamic pressure of steady and transient conditions and inner flow for the ballast pump are tested and analyzed. The results show that the dynamic pressure of each study scheme has cyclical increasing trends, however, the larger the amplitude of the flow rate reduction is, the greater the pressure increasing rate of the two measuring points. While the flow rate decreases to 0.4× Qd and 0.2× Qd, the rate of pressure increase is first fast and then slow. The dynamic pressure pulsation intensity is higher than the corresponding steady-state conditions after the transient conditions. With the increase in flow rate reduction, the characteristic frequencies of the dynamic pressure are 1APF (axial passing frequency) and 1BPF (blade passing frequency) and their harmonic frequency. The rapid decrease in flow rate causes the separation vortex in the impeller channel to be generated in advance, and the scale increases, which reduces the pulsation intensity of the pump outlet to prevent an increase in the level of broadband pulsation between 2APF and 1BPF.

scholarly journals Vacuum Fluctuation in a 2×3 Tandem Milking Plant in Dependence on the Vacuum Control Method

2016 ◽  
Vol 64 (3) ◽  
pp. 775-779
Author(s):  
Jiří Fryč ◽  
Josef Los ◽  
Radovan Kukla ◽  
Tomáš Lošák ◽  
Kristina Somerlíková
Keyword(s):  
Flow Rate ◽  
Control Method ◽  
Frequency Converter ◽  
Control Valve ◽  
Control Methods ◽  
Vacuum Fluctuation ◽  
Variable Flow

Vacuum fluctuation was measured using three different vacuum control methods. Firstly, the use was made of a control valve delivered by the manufacturer; then, an additionally installed frequency converter was used. Lastly, a frequency converter fitted with the stabilisation device prototype was used. First, the control sensitivity according to ISO was measured in all three alternatives. Then the vacuum fluctuation during milking was measured. To conduct the measurements under objectively identified conditions, another measurement was conducted with the air feed during milking being replaced with a precisely defined variable flow rate. The conducted measurement confirmed the fact that when the frequency converter is used, the vacuum fluctuation in the stabilised condition is at the same level as when the control valve is used. If there are sudden changes in the flow rate and the frequency converter is used, the vacuum fluctuation increases. The proposed stabilisation device prototype can reduce the fluctuation.

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