Proportional Solenoid Research Articles

Comparative Analysis of Armature Structure on Constant Force Characteristics in Long-Stroke Moving-Iron Proportional Solenoid Actuator

The influence of key design parameters on the constant force characteristics of long-stroke moving-iron proportional solenoid actuators (MPSAs) has been explored by a method combining finite element modelling and correlation analysis. First, the finite element model (FEM) of long-stroke MPSA was developed and validated. Subsequently, the two evaluation indexes, the average-output solenoid force and maximum-output solenoid force variability, were introduced to disclose the influence law of pole shoe parameters on the constant force characteristics of a long-stroke MPSA. After that, correlation analysis was employed to quantify the influence of several parameters and parameter interaction factors on the constant force characteristics. The results indicate a strong contradiction between the average-output solenoid force and maximum-output solenoid force variability; however, increasing the inner diameter of the cone helps enhance the average-output solenoid force without causing maximum-output solenoid force variability to increase. Among all the parameters examined, the cone angle is the most significant parameter affecting the constant force characteristics. Additionally, interactions between the cone angle and the cone length, the cone angle and the inner cone diameter, the cone angle and the outer cone diameter, the cone length and the outer cone diameter, as well as the inner cone diameter and the outer cone diameter also have an important influence on the constant force characteristics. This study deepens our understanding of how the key parameters affect the constant force characteristics and assists designers in optimizing these parameters for developing new structures.

A novel data fusion based intelligent identification approach for working cycle stages of hydraulic excavators

Accurately identifying the stage of the excavator working cycle is the prerequisite to achieve the staged energy-saving control. However, current identification methods often overlook the influence of hydraulic system latency on identification results and depend on a single model, resulting in poor generalization performance of the identification approaches. Moreover, expert calibration system remains a necessary factor for improving identification accuracy. Aiming at these issues, a hybrid multi-scale feature extractor and a decision-level data fusion classifier approach (HMSFE-DFC) is proposed to identify the working cycle stages of excavator. The input signal employs mixed signals from the main pump pressure and the control current of the proportional solenoid valve to reduce the response delay caused by the single main pump pressure signal. A hybrid multi-scale feature extractor is constructed using a convolutional neural network temporal self-attention feature extraction mechanism and one-dimensional ResNet-50 architecture to extract multiscale features. To prevent overfitting, a decision-level data fusion classifier is used to fuse the decisions information of numerous classifiers. The accuracy of stage identification for 10 consecutive working cycles reaches 95.21%, which verifies its effectiveness.

Smart Control of DCT Proportional Solenoid Valve Based on Data Mining

Smart Control of DCT Proportional Solenoid Valve Based on Data Mining

On the hysteresis characteristics and compensation control strategy of a pneumatic hydrodynamic retarder

As the core component of the hydrodynamic retarder braking system, pneumatic proportional solenoid valve plays an important role in the process of braking torque control. However, the hysteresis characteristic caused by friction and air compressibility will lead to the deviation of braking torque. In order to solve this problem, the hysteresis characteristic of pneumatic proportional solenoid valve is experimentally studied, and the causes of hysteresis phenomenon are analyzed through mathematical modeling of the valve core. Then, a high-precision prediction model of braking torque is obtained by combining Computational Fluid Dynamics (CFD) and response surface method, which is used to construct the mapping relationship between control air pressure and braking torque. Furthermore, a feedforward controller based on Prandtl–Ishlinskii inverse model is designed to compensate the hysteresis characteristics. On this basis, a compound hysteresis characteristics compensation control strategy combined with Proportional Integral Derivative (PID) feedback control is proposed to realize the accurate control of braking torque. Finally, the test verification of braking torque control is carried out. The average error of compound control, feedforward control, and PID control under torque step working condition is 3.16%, 5.97%, and 6.23%, and the response time is 3.75, 8.75, and 3.2 s, respectively. The compound control strategy also has smaller torque error and shorter response time under both ramp torque tracking and constant torque conditions. To sum up, this compound control strategy can effectively compensate the hysteresis characteristics of the pneumatic hydrodynamic retarder and ensure the driving safety by improving the control accuracy and response speed of braking torque.

Multi-Objective Optimization of a Long-Stroke Moving-Iron Proportional Solenoid Actuator.

In this study, the performance of a long-stroke moving-iron proportional solenoid actuator (MPSA) was improved by combining numerical simulations and experiments. A finite element model of the MPSA was developed; its maximum and mean relative absolute errors of electromagnetic force were 4.3% and 2.3%, respectively, under typical work conditions. Seven design parameters including the cone angle, cone length, depth of the inner hole of the coil skeleton, cone width of the armature, inner cone diameter, and initial position of the moving-iron core were selected for developing the model, and the coefficient of the variation in electromagnetic force, nominal acceleration, 95% of the maximum stable output electromagnetic force, and corresponding response time were used as the performance indicators. The constraint relation between each performance indicator and the influence of each design parameter on the performance indicators were revealed using the uniform Latin hypercube experiment design, correlation analysis, and the main effect analysis method. A multi-objective optimization mathematical model of the MPSA was developed by combining traditional surrogate and machine learning models. The Pareto solution set was obtained using the nondominated sorting genetic algorithm II (NSGA-II), and three decision schemes with different attitudes were determined using the Hurwicz multi-criteria decision-making method. The results showed that a strong contradiction exists among the 95% of the maximum stable output electromagnetic force and its corresponding response time and the coefficient of the variation in electromagnetic force. The cone angle considerably influenced the performance indicators. Compared with the initial design, the coefficient of the variation in electromagnetic force was reduced by 54.08% for the positive decision, the corresponding response time was shortened by 15.65% for the critical decision, and the corresponding acceleration was enhanced by 10.32% for the passive decision. Thus, the overall performance of the long-stroke MPSA effectively improved.

Comprehensive study of on-the-go sensing and variable rate application of liquid nitrogenous fertilizer

Variable rate technology (VRT) provides a sustainable, efficient, and cost-effective nutrient application option. A pioneered study is carried out to develop a variable rate liquid fertilizer application system to detect on-the-go deficiency of Nitrogen within a field and apply it according to the requirement of crop. The system includes microcontroller, nitrogen sensor (i.e. Green-seeker sensor), proportional solenoid valve, pressure relief valve, pump, battery, etc. Microcontroller receives a signal from Green-seeker sensor and it transmits to the proportional solenoid valve (PSV). The PSV opening is change based on the prescribed nutritional dose. The experimental study is conducted on groundnut crop. The experiment is carried out for different level of fertilizer (N1-150, N2– 200, N3-250, and N4-300 l ha−1) as well as different operating speed is 3, 4, 5 km h−1 to estimate actual fertilizer dropped (AFD), % error, droplet size, droplet density (DD), uniformity coefficient (UC), and spray deposition. The response time of the system is in the range of 1.12 s to 1.80 s. It is observed from the experimental study that the error in the fertilizer to be dropped and AFD increases with increase in the speed of operation. The percentage error is found to be 2.73 %, which is the lowest one, at 3 km h−1 operating speed. The maximum droplet size is found to be 272.5 μm at 5 km h−1 forward speed and 300 l ha−1 nitrogen application rate, whereas minimum droplet size is found to be 241.23 μm at 3 km h−1 forward speed and 150 l ha−1 nitrogen application rate. The present study proposes maximum of 24.30 % saving in the fertilizer application for groundnut crop. Thus, the present system improved fertilizer use efficiency, profitability while minimizing environmental hazards.

Thermal Load Model of a Proportional Solenoid Valve Based on Random Load Conditions

Drastic changes in the random load of an electromechanical system bring about a reliability problem for the proportional solenoid valve based on a thermal effect. In order to accurately and effectively express the thermal load of a proportional solenoid valve under random load conditions and to meet the requirements of online acquisition, adaptive anomaly detection, and the missing substitution of thermal load data, a thermal load prediction model based on the Kalman filter algorithm is proposed. Taking the compound operation process of an excavator as the object and based on the field testing of an excavator and the independent testing experiment of a proportional solenoid valve in a non-installed state, a method of obtaining historical samples of the proportional solenoid valve’s power and thermal load is given. The k-means clustering algorithm is used to cluster the historical samples of the power and thermal load corresponding to the working posture of a multi-tool excavator. The Grubbs criterion is used to eliminate the outliers in the clustering samples, and unbiased estimation is performed on the clustering samples to obtain the prediction model. The results show that the cross-validation of the sample data under the specific sample characteristics of the thermal load model was carried out. Compared with other methods, the prediction accuracy of the thermal load model based on the Kalman filter is higher, the adaptability is strong, and the maximum prediction deviation percentage is stable within 5%. This study has value as a reference for random cycle thermal load analyses of low-frequency electromechanical products.

Modeling and testing for continuously adjustable damping shock absorber equipped with proportional solenoid valve

Modeling and testing for continuously adjustable damping shock absorber equipped with proportional solenoid valve

A Theoretical Study of Solenoid Inductive Effect on Propagation Delay in Closed Feedback Control

Solenoid is widely and commonly used electro-mechanical devices in industrial processes and engines for hydraulic, fuel and pneumatic controls. The speed, reliability and response time of solenoids can be used to characterize their performance especially where propagation delay can cause instability in the system. In this paper, we model the dynamic characteristics of a proportional solenoid, and investigate its effect on the overall response time in closed loop. The transfer function of the proportional translational motion solenoid at different positions of the plunger is derived. Appropriate boundary conditions are applied to solve transients and stead state current and deduce the response time of the system. At different resistance and inductance, the results show that the rising and settling times of a solenoid system is inversely to the values of Resistance-Inductance (R-L) pair. The lower the values of R-L pair, the higher the rising and settling times. The transient current is shown to be inversely proportional to the values of R-L pair. Solenoid with lowest resistance has the highest transient current flowing through it. These indicates that the selection of solenoid R-L parameters are important consideration in closed loop control system designs.

Research on Push-Pull Energy Storage PWM Power Drive of High-Power High-Response Proportional Solenoid

As the traditional power drive circuit is difficult to meet the requests of high-power high-frequency proportional solenoid fast drive, this paper proposes a push-pull energy storage PWM power drive circuit. The circuit is equipped with an energy storage module, which releases energy when the proportional solenoid coil is charged, supplements the output of the power supply current, and shortens the arrival time of the steady-state current. When the coil is discharged, it recovers energy and shortens the time for the coil current to return to zero. In this paper, a theoretical model of push-pull energy storage power drive circuit is established, and simulation analysis and experimental verification are carried out for a proportional solenoid coil with rated current of 3.3A and power of 79W. The results show that the push-pull storage PWM power drive has excellent input-output linearity, minimal ripple, and good steady-state current output performance. Compared with the traditional single switch and reverse discharging power drives, the coil charging speed under the push-pull energy storage type power drive is increased by 25%, and the discharge speed is increased by 95% and 45% respectively.

A novel gas turbine simulator for testing hybrid solar-Brayton energy systems

A novel gas turbine simulator is developed to establish controllable boundaries for investigating the characteristics of key components in gas turbine based hybrid energy systems under different operating conditions. The gas turbine simulator consists of a compressed air system, an electrical heater, a mass flow controller, a proportional solenoid valve, a dual-flow choked nozzle, and a PLC-based control system. With the proposed control strategy, the fluid parameters, such as temperature, mass flow rate, and pressure, can be automatically regulated to simulate the boundary conditions of a gas turbine under various workloads. Experimental results for both cold and hot states have validated the capabilities of the gas turbine simulator to deliver convergent control results with fast response. The gas turbine simulator has demonstrated considerable performance in stabilizing system boundaries with the precision in terms of pressure control reaching ±0.004 bar for steady states, and ±0.018 bar to ±0.076 bar for transient states with mass flow and temperature perturbations. The gas turbine simulator can also accurately track linear and nonlinear trajectories during operating point migrations, and effectively limit deviations within ±0.037 bar.

Novel modulation approach of flat force–displacement characteristic of linear electro-mechanical converter for electro-hydraulic servo-proportional valve

Flat force–displacement characteristic has crucial influence on the performance of linear electro-mechanical converter of electro-hydraulic servo-proportional valves. The commercial proportional solenoids obtain such features by welding a non-magnetic separator ring, which is complicated and time-consuming. This article presents a novel modulation approach to obtain the flat force–displacement characteristic of linear electro-mechanical converter by constructing a by-pass air gap. Taking an existing linear force motor as an example, the force–displacement characteristic curves of the linear force motor with by-pass air gap and without by-pass air gap are both studied using magnetic circuit analysis and finite element method under different excitation currents. Based on the finite element method simulated data, the response surface method is used to perform the experiment design for structure parameters of linear force motor with by-pass air gap, and the quadratic fitting equations are obtained for further optimization. To balance conflicted design objectives such as linearity, mean value of output force and power-to-weight ratio, the structural parameters of the linear force motor with by-pass air gap are optimized using a multi-objective optimization algorithm based on particle swarm. Prototypes of linear force motor with by-pass air gap and without by-pass air gap are both manufactured, and a special test rig is built. The static and dynamic experimental results are consistent with the theoretical analysis. The former proves that the linear force motor with by-pass air gap can obtain a nearly flat force–displacement curve with reasonable parameter optimization and also improve output force, and the latter reveals that a linear electro-mechanical converter with flat–displacement characteristic has better working stability over common ones. The proposed modulation approach provides a new approach for the design of flat force–displacement characteristic of linear electro-mechanical converter.

Automated Barometric Chamber for Entomology Experiments: Arthropods’ Behavior and Insect-Plant Interactions

Insect behaviors, such as flying, oviposition, parasitism, mating/calling, response to semiochemicals, and others, might be influenced by barometric pressure fluctuations. Abiotic factors controlled in the laboratory facilitate the observation of particularities related to development, behavior, and/or habits of arthropods and plants and their interactions. This study aimed to design an automated barometric chamber for research on arthropod behaviors and insect–plant interactions in the laboratory. The barometric chamber is a transparent box equipped with a single-board computer. An air pump and two proportional solenoid valves were used as actuators to control the air flow, while barometric pressure, air humidity, and temperature sensors were used to monitor the conditions within the chamber. A graphical user interface to operate the barometric chamber was developed to run in a web browser. The barometric chamber was designed to allow the barometric pressure to be changed by up to 15 hPa with respect to the local barometric pressure. In addition, the control system makes it possible to set the rise/fall time (ramp) corresponding to the duration in which a change of pressure will be conditioned. Short- and long-term evaluations demonstrated that the control system can assure pressure stability of ±0.1 hPa with respect to the setpoint value. For demonstration purposes, two experiments were carried out to evaluate the influence of barometric pressure on the feeding activity of Euschistus heros and Diabrotica speciosa. For E. heros, the number of stylet sheath was significantly increased under high pressure conditions compared to the low pressure. However, for D. speciosa, there was no statistical difference in leaf consumption at the evaluated testing conditions.

Optimization of Proportional Solenoid for Flow Control Valve using Recursive Method in OCTAVE and FEMM

Optimization of Proportional Solenoid for Flow Control Valve using Recursive Method in OCTAVE and FEMM by Tom Thampy, Emmanuel Gospel Raj Rivington * , Rajath Chandrashekar Additive and Smart Manufacturing Processes, Central Manufacturing Technology Institute, Bangalore, 560022, India * Author to whom correspondence should be addressed. Journal of Engineering Research and Sciences, Volume 1, Issue 5,

OpenHumidistat: Humidity-controlled experiments for everyone

Humidity control is a crucial element for a wide variety of experiments. Yet, often naive methods are used that do not yield stable regulation of the humidity, are slow, or are inflexible. PID-based electropneumatic humidistats solve these problems, but commercial devices are not widespread, typically proprietary and/or prohibitively expensive. Here we describe OpenHumidistat: a free and open-source humidistat for laboratory-scale humidity control that is affordable (€500) and easy to build. The design is based around mixing a humid and dry air flow in varying proportions, using proportional solenoid valves and flow sensors to control flow rates. The mixed flow is led into a measurement chamber, which contains a humidity sensor to provide feedback to the controller, to achieve closed-loop humidity control.

Development of a Low Cost Ventilator using a Proportional Solenoid Valve

This paper describes the development of portable mechanical ventilator using a proportional solenoid valve whose aim is to regulate the flow rate of oxygen to the patient together with an Arduino Mega2560 as the main controller for the machine before delivering the required volume to the patient; base on their ideal body weight so as to prevent blowing out the lungs The aimed of this development is to save and improve the quality of lives of patients with respiratory problems rather than replacing the existing ventilator. Furthermore, test analysis was conducted to evaluate its performance and also the comparative analysis between the standard and the developed ventilator showed the reasons why most hospitals don’t have ventilators.

Multistage Digital-to-Analogue Chip Based on a Weighted Flow Resistance Network for Soft Actuators.

A control chip with a multistage flow-rate regulation function based on the correlation between the flow resistance and flow rate has been developed in this article. Compared with the traditional proportional solenoid valve, this kind of flow valve based on microfluidic technology has the characteristics of being light-weight and having no electric drive. It solves such technical problems as how the current digital microfluidic chip can only adjust the flow switch, and the adjustment of the flow rate is difficult. To linearize the output signal, we propose a design method of weighted resistance. The output flow is controlled by a 4-bit binary pressure signal. According to the binary value of the 4-bit pressure signal at the input, the output can achieve 16-stage flow adjustment. Furthermore, we integrate the three-dimensional flow resistance network, multilayer structure microvalve, and parallel fluid network into a single chip by using 3D printing to obtain a modular flow control unit. This structure enables the microflow control signal to be converted from a digital signal to an analogue signal (DA conversion), and is suitable for microflow driving components, such as in microfluidic chip sampling systems and proportional mixing systems. In the future, we expect this device to even be used in the automatic control system of a miniature pneumatic soft actuator.

Airborne Mid-Infrared Cavity enhanced Absorption spectrometer (AMICA)

Abstract. We describe the Airborne Mid-Infrared Cavity enhanced Absorption spectrometer (AMICA) designed to measure trace gases in situ on research aircraft using Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS). AMICA contains two largely independent and exchangeable OA-ICOS arrangements, allowing for the simultaneous measurement of multiple substances in different infrared wavelength windows tailored to scientific questions related to a particular flight mission. Three OA-ICOS setups have been implemented with the aim to measure OCS, CO2, CO, and H2O at 2050 cm−1; O3, NH3, and CO2 at 1034 cm−1; and HCN, C2H2, and N2O at 3331 cm−1. The 2050 cm−1 setup has been characterized in the laboratory and successfully used for atmospheric measurements during two campaigns with the research aircraft M55 Geophysica and one with the German HALO (High Altitude and Long Range Research Aircraft). For OCS and CO, data for scientific use have been produced with 5 % accuracy (15 % for CO below 60 ppb, due to additional uncertainties introduced by dilution of the standard) at typical atmospheric mixing ratios and laboratory-measured 1σ precision of 30 ppt for OCS and 3 ppb for CO at 0.5 Hz time resolution. For CO2, high absorption at atmospheric mixing ratios leads to saturation effects that limit sensitivity and complicate the spectral analysis, resulting in too large uncertainties for scientific use. For H2O, absorption is too weak to be measured at mixing ratios below 100 ppm. By further reducing electrical noise and improving the treatment of the baseline in the spectral retrieval, we hope to improve precision for OCS and CO, resolve the issues inhibiting useful CO2 measurements, and lower the detection limit for H2O. The 1035 and 3331 cm−1 arrangements have only partially been characterized and are still in development. Although both setups have been flown and recorded infrared spectra during field campaigns, no data for scientific use have yet been produced due to unresolved deviations of the retrieved mixing ratios to known standards (O3) or insufficient sensitivity (NH3, HCN, C2H2, N2O). The ∼100 kg instrument with a typical in-flight power consumption of about 500 VA is dimensioned to fit into one 19 in. rack typically used for deployment inside the aircraft cabin. Its rugged design and a pressurized and temperature-stabilized compartment containing the sensitive optical and electronic hardware also allow for deployment in payload bays outside the pressurized cabin even at high altitudes of 20 km. A sample flow system with two parallel proportional solenoid valves of different size orifices allows for precise regulation of cavity pressure over the wide range of inlet port pressures encountered between the ground and maximum flight altitudes. Sample flow of the order of 1 SLM (standard litre per minute) maintained by an exhaust-side pump limits the useful time resolution to about 2.5 s (corresponding to the average cavity flush time), equivalent to 500 m distance at a typical aircraft speed of 200 m s−1.

Experimental and numerical validation of a proportional solenoid valve based on the data-driven model

Solenoid valves are widely used in mechatronics, robotic systems and industrial occasions. An accurate model is very important for the design and control of a solenoid valve. The dynamical model of the solenoid valve is difficult to obtain due to the complexity of the structure and the interaction of multiple physical fields. This paper proposes two kinds of model of solenoid valve: grey box model and black box model, on the basis of experimental data. ARX model is selected as the basic structure of the grey box model. After clustering the data with the fuzzy c-means algorithm, the overall experimental data is divided into several local linear sub-models, and the model coefficients of the local linear model are obtained by partial least square regression. The overall expression of the model is obtained by combining the local sub-models with membership degree. For the black box model, support vector regression algorithm is used to identify. On the basis of selecting the appropriate parameters, we obtain the black box model of solenoid valve based on data. For the above two models, we carry out experimental verification and error analysis, and compare with the traditional modelling method. According to the results, it can be seen that on the basis of the experimental data, using the data-driven method to construct the model has many advantages, avoiding complex physical analysis, and has high accuracy. The model with high precision will be used in the accurate control and observing estimation of the solenoid valve.

Design, construction, and testing of an accurate low-cost humidistat for laboratory-scale applications

Stable and precise control of humidity is imperative for a wide variety of experiments. However, commercially available humidistats (devices that maintain a constant humidity) are often prohibitively expensive. Here, we present a simple yet effective humidistat for laboratory-scale applications that can be easily and affordably (<€250) constructed based on an Arduino Uno as microcontroller, a set of proportional miniature solenoid valves, a gas washing bottle, and a humidity sensor. The microcontroller implements a PID controller that regulates the ratio of a dry and humid airflow. The design and implementation of the device, including a custom driver circuit for the solenoids, are described in detail, and the firmware is freely available online. Finally, we demonstrate its proper operation and performance through step response and long-term stability tests, which shows settling times of approx. 30 s and an attainable relative humidity range of 10–95%