Pneumatic Valve Research Articles

Frequency-Controlled Fluidic Oscillators for Soft Robots.

Electronic-free controls have recently emerged as one of the main topics in soft robotics. However, electronic-free fluidic circuits still lack controllability and reconfigurability to achieve different functions. Here, reconfigurable pneumatic valves that widen the design space of fluidic circuits are presented. The significance of two parameters on the valve's operation: a pre-defined manufacturing parameter that sets the initial operational range of the valve, and a second, on-the-fly modifiable geometric parameter that shifts the behavior of the valve during operation is shown. It is demonstrated that equipping the valve with these reconfigurable features enables the tuning of fluidic oscillatory circuits as illustrated by two examples: a frequency-controlled relaxation oscillator and a reconfigurable ring oscillator. The relaxation oscillator is employed to control the actuation frequency of a soft hopper, which is able to achieve 80 to 125 hops min-1 and a hopping speed ranging from ≈1 to ≈1.185 BL s-1. Additionally, the reconfigurable ring oscillator is used to demonstrate how each output frequency can be controlled independently, via a soft robotic crawler that can navigate in three directions, and a volume-controlled fluidic pump able to achieve mixing of solutions in environments where electronic components cannotoperate.

Fault Diagnosis of Maritime Equipment Using an Intelligent Fuzzy Framework

The task of automatically and intelligently diagnosing faults in marine equipment is of great significance due to the numerous duties that shipboard professionals must handle. Incorporating automated and intelligent systems on ships allows for more efficient equipment monitoring and better decision-making. This approach has attracted considerable interest in both academia and industry because of its potential for economic savings and improved safety. Several fault diagnosis methods are documented in the literature, often involving mathematical and control theory models. However, due to the inherent complexity of some processes, not all characteristics are precisely known, making mathematical modeling highly challenging. As a result, fault diagnosis often depends on data or heuristic information. Fuzzy logic theory is particularly well suited for processing this type of information. Therefore, this paper employs fuzzy models to diagnose faults in a marine pneumatic servo-actuated valve. The fuzzy models used in fault diagnosis are obtained from the data. These fuzzy models are identified for the normal operation of the marine pneumatic servo-actuated valve, and for each fault, predicting the system’s outputs from the inputs and outputs of the process. The proposed fault diagnosis framework analyzes the discrepancy signals between the outputs of the fuzzy models and the actual process outputs. These discrepancies, known as residuals, help in detecting and isolating equipment faults. The fault isolation process uses an intelligent decision-making approach to determine the specific fault in the system. This method is applied to diagnose abrupt faults in a marine pneumatic servo-actuated valve. The approach presented was used to detect and diagnose three very important faults in the operation of a marine pneumatic servo-actuated valve. The three faults were correctly detected and isolated, and no errors were detected in this detection and isolation process.

Research on the characteristics of a pneumatic proportional valve

Abstract The execution of autonomous driving in heavy-duty trucks necessitates stringent regulation of their braking torque output. Hydraulic retarder serves as a widely auxiliary braking system in heavy-duty vehicles, with the pneumatic proportional valve functioning as the core component of its control system, regulating the output response and control precision of the braking torque of the hydraulic retarder. To improve the accuracy of brake torque control for hydraulic retarders, it is critical to conduct thorough research on the control system, especially the pneumatic proportional valve. Therefore, A detailed analysis of the working mechanism of pneumatic proportional valves was conducted, encompassing the construction of mathematical and simulation models. The efficacy of the simulation model was confirmed via experimental validation. When the control pressure increases, the simulation results are close to the experimental results, with a maximum discrepancy of 18%; when the control pressure decreases, the simulation results show a similar trend to the experimental results. The research can aid in formulating control methodologies for pneumatic proportional valves and offer theoretical guidelines for future exploration into boosting the precision of hydraulic retarder braking torque control.

Inverse Fuzzy Fault Models for Fault Isolation and Severity Estimation in Industrial Pneumatic Valves

Inverse Fuzzy Fault Models for Fault Isolation and Severity Estimation in Industrial Pneumatic Valves

An electropermanent magnet valve for the onboard control of multi-degree of freedom pneumatic soft robots

To achieve coordinated functions, fluidic soft robots typically rely on multiple input lines for the independent inflation and deflation of each actuator. Fluidic actuators are controlled by rigid electronic pneumatic valves, restricting the mobility and compliance of the soft robot. Recent developments in soft valve designs have shown the potential to achieve a more integrated robotic system, but are limited by high energy consumption and slow response time. In this work, we present an electropermanent magnet (EPM) valve for electronic control of pneumatic soft actuators that is activated through microsecond electronic pulses. The valve incorporates a thin channel made from thermoplastic films. The proposed valve (3 × 3 × 0.8 cm, 2.9 g) can block pressure up to 146 kPa and negative pressures up to –100 kPa with a response time of less than 1 s. Using the EPM valves, we demonstrate the ability to switch between multiple operation sequences in real time through the control of a six-DoF robot capable of grasping and hopping with a single pressure input. Our proposed onboard control strategy simplifies the operation of multi-pressure systems, enabling the development of dynamically programmable soft fluid-driven robots that are versatile in responding to different tasks.

Design and Development of Combined Mechanical and Pneumatic Valve Spring Remover

A combined mechanical and pneumatic valve spring remover is used to remove or install valve springs from an engine while the cylinder head is mounted on the engine or supported on a workbench (off the head). The designed tool was adjustable and mounted over the cylinder head by a stud. It can operate manually to depress the spring or by using an air compressor for a pneumatic actuator. The model of the tools is done by SOLIDWORK 2021 and we selected the stainless steel AISI grade-304(12) material. Tools were made following the calculations that have been done on valve springs. From the data calculation, the force required to depress the valve spring is 1350 N but the tools were designed to produce 1962.5 N by considering some friction loss. The analysis of the pneumatic system done by ANSYS software shows acceptable results like, Von Mises stress (20.036 MPa), maximum principal stress (26.426 MPa), and the total deformation becomes 1.6029×10-3. The prototype was built, and the test was carried out in time efficiently during the removal or installation of the valve spring on Engine YaMZ-238. The test result shows that to remove 4 springs, the designed tool is very effective to use by optimizing the difference in time savings of an average of 1 minute and 17 seconds when removing the spring valve, and 1 minute and 26 seconds when installing the valve, even when we use it mechanically. The developed valve spring remover has several advantages over the standard C-clamp tools, such as greater precision and accuracy in removing valve springs, reduced labor and time required for the task, and Increased safety with minimal human force.

Prediction of packing performance of pneumatic control valve based on stem mechanism model and VMD-SSA-LSTM

Abstract Packing performance is one of the most important parts affecting the control operation of pneumatic control valves. In order to avoid the failure caused by packing wear and aging of pneumatic control valves after long-term use, this paper constructs a valve stem mechanism model and combines the advantage of deep learning to predict the packing performance of pneumatic control valves based on Long Short-term Memory (LSTM) and Variable Mode Decomposition (VMD) and Sparrow Search Algorithm (SSA). Firstly, the historical data of the actuator is calculated based on the mechanism model of the valve stem. The time-friction force obtained by the calculation is the parameter set. After the parameter set is subject to the variational mode decomposition, the parameter set is imported into the SSA-LSTM prediction model for prediction, and the prediction data is obtained.

Body-Mounted MR-Conditional Robot for Minimally Invasive Liver Intervention.

MR-guided microwave ablation (MWA) has proven effective in treating hepatocellular carcinoma (HCC) with small-sized tumors, but the state-of-the-art technique suffers from sub-optimal workflow due to the limitedaccuracy provided by the manual needle insertions. This paper presents a compact body-mounted MR-conditional robot that can operate in closed-bore MR scanners for accurate needle guidance. The robotic platform consists of two stacked Cartesian XY stages, each with two degrees of freedom, that facilitate needle insertion pose control. The robot is actuated using 3D-printed pneumatic turbines with MR-conditional bevel gear transmission systems. Pneumatic valves and control mechatronics are located inside the MRI control room and are connected to the robot with pneumatic transmission lines and optical fibers. Free-space experiments indicated robot-assisted needle insertion error of 2.6 ± 1.3 mm at an insertion depth of 80mm. The MR-guided phantom studies were conducted to verify the MR-conditionality and targeting performance of the robot. Future work will focus on the system optimization and validations in animal trials.

Multimodal soft valve enables physical responsiveness for preemptive resilience of soft robots.

Resilience is crucial for the self-preservation of biological systems: Humans recover from wounds thanks to an immune system that autonomously enacts a multistage response to promote healing. Similar passive mechanisms can enable pneumatic soft robots to overcome common faults such as bursts originating from punctures or overpressurization. Recent technological advancements, ranging from fault-tolerant controllers for robot reconfigurability to self-healing materials, have paved the way for robot resilience. However, these techniques require powerful processors and large datasets or external hardware. How to extend the operational life span of damaged soft robots with minimal computational and physical resources remains unclear. In this study, we demonstrated a multimodal pneumatic soft valve capable of passive resilient reactions, triggered by faults, to prevent or isolate damage in soft robots. In its forward operation mode, the valve, requiring a single supply pressure, isolated punctured soft inflatable elements from the rest of the soft robot in as fast as 21 milliseconds. In its reverse operation mode, the valve can passively protect robots against overpressurization caused by external disturbances, avoiding plastic deformations and bursts. Furthermore, the two modes combined enabled the creation of an endogenously controlled valve capable of autonomous burst isolation. We demonstrated the passive and quick response and the possibility of monolithic integration of the soft valve in grippers and crawling robots. The approach proposed in this study provides a distributed small-footprint alternative to controller-based resilience and is expected to help soft robots achieve uninterrupted long-lasting operation.

The Distributed Parameter Model of an Electro-Pneumatic System Actuated by Pneumatic Artificial Muscles with PWM-Based Position Control

Today, the analysis and synthesis methods of electro-pneumatic systems with position control actuated by pneumatic artificial muscles (PAMs) are quite well known. In these methods, pneumatic artificial muscle is considered as an object with lumped parameters. However, the PAM is an object with distributed parameters, where the pressure, density, and mass flow rate of gas are varied along the bladder length. Thus, in the case of certain design parameters of the pneumatic artificial muscle and certain frequencies of the supply pressure, resonant gas oscillations affected by the wave processes in the bladder may occur. Thereby, in the PWM-driven PAM-actuated system, certain operation frequencies of the control pneumatic valve can cause oscillations of gas in the bladder and in the connected pipeline. These processes could lead to vibrations of the executive device. To solve this practical problem, a distributed parameter model of the PAM that takes into account the pressure fluctuations in the bladder and in the pipeline was elaborated. Also, in this work, a new method in which the wave processes are described by ordinary differential equations instead of partial differential equations was proposed.

Stiction parameter identification for pneumatic valves with a simultaneous approach

In industrial processes, stiction in control valves is a common cause of degradation in control loop performance. It is important to identify and establish reliable stiction models to enhance control loop performance. This study focuses on constructing a precise model of the pneumatic control valve using the LuGre friction model. To improve the model, a smooth function based on probability density is introduced to alleviate the LuGre friction model. The maximum error resulting from this smoothing process is also analyzed. To estimate the valve stiction parameters, the direct transcription method is utilized to convert the problem from systems of ordinary differential equations into a nonlinear programming problem. The interior point method is then used to solve this problem. Furthermore, the estimability of the parameters is analyzed based on the reduced Hessian matrix before estimation. Numerical results demonstrate that the proposed approach in this study effectively estimates the stiction parameters of pneumatic control valves.

Development of a Programmable System Used for the Preparation of a Mixture of Flammable/Explosive Gases

In the present paper, the use of programmable microprocessors to develop a computerized stand for the preparation of a mixture of flammable/toxic/explosive gases in order to obtain mixtures at concentrations in explosive range is presented. The operating principle of the stand is based on the mixing of two volumetric flows, controlled with the help of microprocessors, where gases are stored and circulated at atmospheric pressure through cylindrical injectors, driven by stepper motors so that the gas circuit does not require valves. The exit of the stand is a homogenization chamber, with agitator and sensor to confirm the desired concentration of the mixture. This automated stand eliminates mechanical, electric or pneumatic valves from the gas circuits, avoiding elements with high mechanical resistance suitable for high pressures/depressions, removing the possibility of the return of the gas flow, without sensitivity to sudden pressures variations.

Dynamic analysis and optimization of a novel Dual-valve heave compensator for heavy lifting operations

Traditional Passive Heave Compensator (PHC) requires set parameters before operation according to the specific sea conditions, making it difficult to adapt to complex and variable working environments. This study aims to enhance the environmental adaptability of classical PHC by proposing a novel concept of Dual-valve Heave Compensator (DHC) based on the traditional PHC framework. By modulating the hydraulic and pneumatic throttle valve openings dynamically, the DHC system facilitates adjustments extensively in damping and stiffness, significantly enhancing compensation performances. As an enhancement over traditional models, this study incorporates a coupled dynamic model that accounts for critical influencing factors, including gas temperature and nonlinear friction. A linearized equation for the dynamic stiffness of DHC has been developed based on the small deviation linearization method, extensively analysing the effects of pneumatic parameters on the stiffness characteristics. Furthermore, a design framework employing Latin Hypercube Sampling (LHS) design, Radial Basis Function (RBF) surrogate model, and Non-dominated Sorting Genetic Algorithm-II (NSGA-II) has been specifically developed to address the multi-objective optimization challenges presented by DHC systems. The case study indicates that the optimized DHC can achieve up to 86% compensation accuracy under a 250-ton load with harmonic excitation and offers adjustments flexibly for various operational conditions. Contrary to conventional wisdom, minimal valve openings significantly enhance compensation accuracy during some intervals of irregular wave excitation. These findings confirm the superior performance and potential of DHC relative to traditional PHCs under complex marine environments.

Image-based corn seed embryo orientation detection and adjustment for precision planting

Research has indicated that positioning a corn seed with its embryo side facing upward and its long axis perpendicular to a seeding row leads to the corn leaves growing perpendicular to the seeding row. This positioning results in an increased rate of light interception and yield for the crop. An identification and adjustment prototype was designed to rearrange corn seeds into the aforementioned seed orientation. The main parts are the teeth plate, V-shaped groove, photo sensor, camera, LED light, and pneumatic solenoid valve. When a corn seed enters the prototype, it will first be led to a leaning state, then go through an image acquisition and processing process, where the template matching method will be used to find a region of interest (ROI) on a corn seed image. The embryo side will be identified based on the average normalized saturation value in the ROI. The pneumatic solenoid valve will then be activated to adjust the seed accordingly to the targeted seed orientation. Trial results showed a success rate of 84 % and an average adjustment time of 1.438 s. The proposed method of embryo side direction identification and adjustment will contribute to the development of corn-oriented seeding technology.

Data-Monitoring Solution for Desalination Processes: Cooling Tower and Mechanical Vapor Compression Hybrid System.

The advancement of novel water treatment technologies requires the implementation of both accurate data measurement and recording processes. These procedures are essential for acquiring results and conducting thorough analyses to enhance operational efficiency. In addition, accurate sensor data facilitate precise control over chemical treatment dosages, ensuring optimal water quality and corrosion inhibition while minimizing chemical usage and associated costs. Under this framework, this paper describes the sensoring and monitoring solution for a hybrid system based on a cooling tower (CT) connected to mechanical vapor compression (MVC) equipment for desalination and brine concentration purposes. Sensors connected to the data commercial logger solution, Almemo 2890-9, are also discussed in detail such as temperature, relative humidity, pressure, flow rate, etc. The monitoring system allows remote control of the MVC based on a server, GateManager, and TightVNC. In this way, the proposed solution provides remote access to the hybrid system, being able to visualize gathered data in real time. A case study located in Cartagena (Spain) is used to assess the proposed solution. Collected data from temperature transmitters, pneumatic valves, level sensors, and power demand are included and discussed in the paper. These variables allow a subsequent forecasting process to estimate brine concentration values. Different sample times are included in this paper to minimize the collected data from the hybrid system within suitable operation conditions. This solution is suitable to be applied to other desalination processes and locations.

Numerical simulation of condensation flows of humid air in the high-pressure pneumatic pressure-reducing valve

The phenomenon of condensation and ice formation exists in the high-pressure air pressure-reducing valve (HPAPRV), severely impacting the pressure-reducing valve's aerodynamic performance and operational safety. The problem is that the phase change of humid air in a high-pressure supersonic flow is not fully understood. This study aims to elucidate the condensation effect in high-pressure supersonic flows and the influence of the inlet conditions on the behavior of the condensate flow. A computational humid air phase model has been developed to investigate the formation of massive droplets due to phase-change processes. The numerical approach is validated by comparing it with experimental data, demonstrating a strong correlation between the two. The condensation properties of humid air in HPAPRV are described in detail. The effects of the condensation properties of humid air at different inlet conditions are discussed in detail. The results show that an increase in the inlet pressure increases the level of supersaturation, which increases the nucleation rate and the droplet growth rate and promotes droplet production. Increasing the inlet temperature has little effect on the HPAPRV pressure-reducing performance and predicts the temperature range of water vapor condensation before and after the valve port. The liquid mass fraction can be reduced by 50.9% by increasing the inlet temperature by 30 K, from 283 K to 313 K. When the inlet temperature is below 283 K, water vapor condenses in front of the valve port. Decreasing the inlet humidity reduces the degree and extent of supersaturation, which decreases the nucleation rate and the liquid mass fraction. When low inlet humidity (under 10%), the condensation phenomenon did not almost occur inside the pressure-reducing valve.

Performance Assessment of Pneumatic-Driven Automatic Valves to Improve Pipeline Fault Detection Procedure by Fast Transient Tests.

The use of fast transients for fault detection in long transmission networks makes the generation of controlled transients crucial. In order to maximise the information that can be extracted from the measured pressure time history (pressure signal), the transients must meet certain requirements. In particular, the manoeuvre that generates the transient must be fast and repeatable, and must produce a pressure wave that is as sharp as possible, without spurious pressure oscillations. This implies the use of small-diameter valves and often pneumatically operated automatic valves. In the present work, experimental transient tests are carried out at the Water Engineering Laboratory (WEL) of the University of Perugia using a butterfly valve and a ball pneumatic-driven valve to generate pressure waves in a pressurised copper pipe. A camera is used to monitor the valve displacement, while the pressure is measured by a pressure transducer close to the downstream end of the pipe where the pneumatic valve is installed. The experimental data are analysed to characterise the valve performance and to compare the two geometries in terms of valve closing dynamics, the sharpness of the generated pressure wave and the stability of the pressure time history. The present work demonstrates how the proposed approach can be very effective in easily characterising the transient dynamics.

Intelligent In situ Printing of Multimaterial Bioinks for First‐Aid Wound Care Guided by Eye‐In‐Hand Robot Technology

AbstractINSIGHT (INtelligent in situ printing Guided by Eye‐in‐Hand robot Technology), an innovative computer vision‐enabled system that combines a depth camera with a 6‐degree of freedom robot arm, empowering it to identify arbitrary areas at various angles through real time adjustments and to enable volumetric printing performed by dynamic image recognition based on color and contour differences is presented. Continuous targeting of multiple wounds at different locations is achieved. The optimized pneumatic valve synchronized with the INSIGHT can print multiple inks with diverse rheological properties to fabricate scaffolds and bandages with the capacity to treat various types of wounds. The design of dual printed modes, such as extrusion and spray, can significantly decrease printing time for large‐scale wounds on an ex vivo porcine model. INSIGHT demonstrates its ability to treat diabetic wounds, using a microgel‐based ink possessing an inherent porous microstructure to facilitate cell infiltration. In vivo verification highlights its adaptability to enable customized care for rapid emergency treatment of trauma patients.

Design and Development of Wireless Control of Pneumatic Actuated Robotic Arm

A Pneumatic robotic arm is a type of pick and place robot what is usually used for transferring goods/products from one place to another constantly. There are many types of pick and place robots based on their applications. In this robot we have used neumatic cylinders for the movement of robot. In Pneumatic application the pressurized air plays a vital role. The main motive of the robot is to reduce the consumption of electricity, increase productivity in Industries that requires repetitive and precise movements, reduce human errors. The successful implementation of the pneumatic pick and place robot system will potentially lead to cost saving, increased production capacity, and enhanced overall performance in manufacturing processes. The robot utilizes pneumatic actuators and solenoid valves to perform various tasks. The system will be controlled by microcontroller and programmed to execute specific commands. Grippers are attached at the end of an industrial arm robot for material handling purpose.

Design and Development of Wireless Control of Pneumatic Actuated Robotic Arm

A Pneumatic robotic arm is a type of pick and place robot what is usually used for transferring goods/products from one place to another constantly. There are many types of pick and place robots based on their applications. In this robot we have used pneumatic cylinders for the movement of robot. In Pneumatic application the pressurized air plays a vital role. The main motive of the robot is to reduce the consumption of electricity, increase productivity in Industries that requires repetitive and precise movements, reduce human errors. The successful implementation of the pneumatic pick and place robot system will potentially lead to cost saving, increased production capacity, and enhanced overall performance in manufacturing processes. The robot utilizes pneumatic actuators and solenoid valves to perform various tasks. The system will be controlled by microcontroller and programmed to execute specific commands. Grippers are attached at the end of an industrial arm robot for material handling purpose.