Pneumatic Circuit Research Articles

SYNTHESIS OF HYDROPNEUMATIC DRIVE SYSTEM SCHEMES ON SEVEN-LINEAR DISTRIBUTORS

The purpose of the article is an in-depth study of ways to improve hydraulic and pneumatic systems using seven-line distributors. The main advantages focused on include increased efficiency, increased ease of installation, reduced hardware costs, and lower cost of the hydropneumatic actuator, these are the main components that must be guided when designing hydraulic and pneumatic circuits. When achieving these indicators, the hydraulic equipment used in the system plays an important role. Due to the idea of using extremely universal modules, the article investigated distributors with more lines than in standard solutions, namely seven-line hydraulic and pneumatic distributors. The conventional notation of the seven-line distributor is given. The minimal combinations of functions that can be implemented using seven-linear distributors are considered. It was determined what can be considered a trigger. Examples of the use of seven-line dividers in the construction of flip-flops with a dominant zero and flip-flops with a counting input are given. A detailed description of the operation of such triggers is given. The possibility of expanding the functions of the command apparatus was investigated. A detailed description of the command apparatus built on seven-line distributors is made. The definition of the concept of graph of operations is given. A graph of operations for a molding machine is built. On the basis of this graph, logical equations are constructed that describe the entire system operation process and transition states, taking into account the signals that move the system to the next state and the signals acting inside the transition. A pneumatic circuit for the molding machine was also constructed based on the obtained logic equations. A seven-line command apparatus was used to build this scheme, which demonstrates the possibilities of using a seven-line command apparatus in practical conditions. The areas of application of such command apparatus and seven-line distributors are considered.

Research on Pneumatic Manipulator Control Methods

With the rapid development of pneumatic technology, there has been an increasing focus on leveraging pneumatic manipulator equipment that offers a blend of affordability, high performance, and numerous advantages, catering to the diverse needs of modern production practices. Pneumatic manipulators stand out among controlled manipulators due to their cost-effectiveness, straightforward design, impressive power-to-volume ratio, environmentally friendly operation, and robust resilience to external interference. This paper delves into addressing significant control deviations encountered during the dynamic movement of pneumatic manipulators, aiming to optimize the manipulator s structure and devise an efficient pneumatic system circuit. Additionally, it harnesses PLC control technology to devise a comprehensive control ladder diagram for the pneumatic manipulator, thereby ensuring precise control over its motion. By validating the feasibility and accuracy of the designed motion control methods, this study contributes to enhancing the overall efficiency and reliability of pneumatic manipulator systems in industrial settings.

An open-source research platform for mechanical ventilation based on Simulink® and STM32 nucleo

Abstract Gain in knowledge in experimental fields of research is mostly achieved using commercial hardware platforms. The linked costs however can limit a broad access by scientists and in the specific case of mechanical ventilation the pandemic demonstrated that further and collective research is essential and necessary. This contribution presents the modular design and implementation of a research platform which is based on STM32 Nucleo boards and Simulink®. The hardware required such as the pneumatic circuit are covered as well as the software architecture in which clinician related settings are processed for control references. The core functionality of mandatory volume controlled (VCV) and pressure controlled ventilation (PCV) while ensuring a positive end-expiratory pressure for the patient ( PEEP ) $(\text{PEEP})$ is evaluated and the foundational software models are published in a repository.

Automation proposal applied to Trolleybus current collector

Automation proposal applied to Trolleybus current collector

Design of an Intelligent Feeding System

The article elaborates on the design method of an intelligent feeding system . The feeding system is an important part of the automatic production line, which provides raw materials for other units of the automatic production line. It is controlled by PLC, which is described from many aspects, such as structure design, pneumatic circuit design, control circuit design and PLC program design. It analyzes the design idea and principle of intelligent feeding system in detail, and provides an effective reference for the design of automatic production line.

Energy Efficiency of Pneumatic Actuating Systems with Pressure-Based Air Supply Cut-Off

To exploit the energy-saving potential of pneumatic actuator systems, various energy-saving circuits have been developed in recent decades. However, the principle of a pressure-based air supply cut-off has only been considered to a limited extent. This article introduces a possible pneumatic circuit solution for this principle and evaluates it via simulation and measurement of the saving potentials and limits of the developed circuit for typical industrial drive tasks. The conducted investigation shows the suitability of the developed energy-saving circuit, especially for the reduction of the actuator oversizing, achieving energy savings of 71% without performance loss. Conversely, applying this principle to an already well-sized cylinder comes with limitations and requires additional damping. The final economic analysis demonstrates that the application of the circuit could achieve comparatively short amortisation times of approx. 1.9 years for a setup with standard pneumatic components.

Development and evaluation of a soft pneumatic muscle for elbow joint rehabilitation.

Elbow joint rehabilitation presents a formidable challenge, underscored by the joint's complex biomechanics and high vulnerability to injuries and degenerative conditions. Despite the advancements in rehabilitative technology, current solutions such as rigid exoskeletons often fall short in providing the precision, flexibility, and customization needed for effective treatment. Although traditional robotic aids, such as rigid exoskeletons, help recover, they lack in providing sufficient flexibility, comfort, and easy customization with no need for complicated calculation and complex design considerations. The introduction of soft pneumatic muscles marks a significant development in the rehabilitation technologies field, offering distinct advantages and unique challenges when compared to conventional rigid systems. These flexible actuators closely mimic the elasticity of biological tissues, improving safety and interaction between humans and machines. Designed for individualized therapy, its versatility allows application in various rehabilitation scenarios, from clinical settings to home settings. The novelty of this approach lies in the development of biomechanically-compliant soft pneumatic muscles optimized for precise rotational control of the elbow joint, coupled with an advanced deep learning-based motion tracking system. This design overcomes limitations in force control, stability, and pressure requirements found in existing pneumatic-based systems, improving the safety and efficacy of elbow rehabilitation. In this study, the design, fabrication and systematic evaluation of a soft pneumatic muscle for elbow rehabilitation are presented. The device is designed to closely simulate the complex biomechanical movements of the elbow, with a primary focus on the rotational motions that are essential for controlling flexion and extension, as well as positioning the wrist during grasping tasks. Through the integration of precise geometric parameters, the actuator is capable of controlled flexion and extension, reflecting the natural kinematics of the elbow. Employing a rigorous methodology, the research integrates finite element analysis with empirical testing to refine the actuator's performance. Under varying air pressures, the soft muscle demonstrated remarkable deformation along the X-axis (10-150mm) and the Y-axis, indicative of its symmetrical rotational behavior, while maintaining minimal elongation along the Z-axis (0.003mm max), and proper lifiting force under a maximum wight of 470gm. highlighting the stability and targeted response of the device to pneumatic actuation. A specialized experimental apparatus comprising a 3D environment, a pneumatic circuit, a LabVIEW-based control system, and a deep learning algorithm was developed for accurate position estimation. The algorithm achieved a high predictive accuracy of 99.8% in spatial coordination tracking, indicating the precision of the system in monitoring and controlling the actuator's motion.

Analysis of electric-free pneumatic circuits based on logic circuit and its application

Analysis of electric-free pneumatic circuits based on logic circuit and its application

A Multi-Layer Stacked Microfluidic Tactile Display With High Spatial Resolution.

Pneumatic tactile displays dynamically customize surface morphological features with reconfigurable arrays of independently addressable actuators. However, their ability to render detailed tactile patterns or fine textures is limited by the low spatial resolution. For pneumatic tactile displays, the high-density integration of pneumatic actuators within a small space (fingertip) poses a significant challenge in terms of pneumatic circuit wiring. In contrast to the structure with a single-layer layout of pipes, we propose a multi-layered stacked microfluidic pipe structure that allows for a higher density of actuators and retains their independent actuation capabilities. Based on the proposed structure, we developed a soft microfluidic tactile display with a spatial resolution of 1.25 mm. The device consists of a 5 × 5 array of independently addressable microactuators, driven by pneumatic pressure, each of which enables independent actuation of the surface film and continuous control of the height. At a relative pressure of 1000 mbar, the actuator produced a perceptible out-of-plane deformation of 0.145 mm and a force of 17.7 mN. User studies showed that subjects can easily distinguish eight tactile patterns with 96% accuracy.

Approximation of the Couette-Poiseuille flow on an annular domain in compressible regime for a hyperloop pod

Fanno flow is one of the most studied problems in fluid mechanics, as it models the pressure losses on domains in which the characteristic length is considerably lower than the height. These types of flows are present in several applications in the industry, such as pipe flows in pneumatic and hydraulic circuits, oil pipelines or air conditioning and water distribution systems. One potential application can be found in hyperloop design, where flow at high speeds moves between the small gap between the capsule and the tube wall. In this case, the domain is annular-shaped instead of a single cylinder, and the interior wall moves at the capsule speed. Although this quasi-1D flow is strongly affected by the wall friction, it cannot be modelled using the standard Fanno expression. Thus, to model the pressure drop without extensive CFD techniques, a simplified 1D analytical expression is developed to estimate the friction losses. The model assumes a constant ratio between the shear stress on the interior and the exterior walls throughout the channel. Then, instead of the hydraulic diameter as in the standard Fanno expression, a new definition of an equivalent diameter is performed to consider the annular-shaped domain and the movement of the interior wall. The new equivalent diameter is always higher than the original used for Fanno flows (hydraulic one), even twice when the wall speed equals the mean speed. This effect leads to smaller pressure losses due to the movement of one of the walls and indicates that the wall movement is always beneficial. To validate the results obtained from the model, they are compared with an equivalent CFD simulation, leading to a maximum deviation of 5% on the Mach number and 7% on the total friction coefficient.

Impact Characteristics of a Bidirectional Pneumatic DTH Hammer for Unconsolidated Formations

With advantages of high efficiency and low cost, DTH hammer drilling has been highly applied in various drilling projects. When drilling in unconsolidated formations, it is prone to drilling accidents such as drilling tools sticking or burying. Thus, a bidirectional pneumatic DTH hammer is designed to drill boreholes using forward impact and release sticking drilling tools using backward impact. With a floating gas distribution mechanism, impact strokes of the DTH hammer piston can be changed when flat keys are in a different position of the key grooves on the gas distribution shaft. In drilling mode, the piston has a larger impact stroke and can impact the anvil at high speeds to drive the bit breaking rocks. When drilling tools become stuck, by changing to a smaller impact stroke, the piston can impact backward on the gas distribution valve to break rocks above the DTH hammer so sticking drilling tools can be released. According to the structure and working principle of the bidirectional pneumatic DTH hammer, a physical model based on the pneumatic transmission circuit is established; then, a simulation model is built with pneumatic transmission module components in software of SimulationX 4.1 student version. Piston velocities, displacements, and impact energy are analyzed, with main factors including piston mass, total weight of the DTH hammer, compressed air pressure, and backward impact stroke being considered. Analysis results show that working characteristics of the DTH hammer are fairly affected by piston mass and compressed air pressure. Based on the changing laws of the impact frequency, peak of impact velocity, and impact energy, a piston mass of 18 kg, total weight of 125 kg, gas source pressure of 2.2 MPa, and lifting distance of 60 mm for backward impact were recommended. To verify the performance of the bidirectional pneumatic DTH hammer, field experiments were carried out in the gravel stratums. The bidirectional DTH hammer was in good working condition and the maximum drilling rate can reach up to 1.5 m/min. By lifting the DTH hammer away from the bottom of the borehole and pumping compressed air, the DTH hammer piston could achieve a high frequency backward impact. There are no drilling tools’ sticking or burying accidents in the drilling experiments. The bidirectional pneumatic DTH hammer can effectively drill boreholes in loose formations and deal with drilling tools’ sticking or burying accidents.

A Toolbox for Designing 3D‐Printing‐Ready Pneumatic Circuits for Controlling Soft Robots

The robotics field has witnessed a rapid increase in the popularity of soft pneumatic robots due to their adaptability to unstructured environments and safe human–robot interaction. However, many of them are still controlled by rigid solenoid valves and microcontrollers. Recent research works have introduced various electronics‐free computational devices for soft robotic applications. Yet, connecting these individual components into pneumatic circuits still remains challenging. The manual circuit design, fabrication, and piping process can bring inefficient circuit layout, redundant tubing, unreliable fittings, and potentially human mistakes. This work presents an open‐source toolbox for automatically designing pneumatic circuits for soft robotic applications. The toolbox takes the desired computation function along with some space constraints as inputs, and generates a 3D‐printable file of a pneumatic circuit that can be fabricated and used directly. This is achieved by efficiently positioning the logic gates and air channels while considering the workspace constraints, fabrication limits, material cost, and system complexity. The versatility of the design automation algorithm has been tested with two different truth tables and six different workspaces. The work also showcases utilizing the toolbox to design a computational circuit that governs the movements of a soft robotic hand with four pneumatic actuators.

Generalizable Electrochemical Biosensors Using DNA-Analyte Conjugates Integrated with Pneumatic Oscillators for Microfluidic Workflow Automation

Sensors based on electrochemical (EC) readout offer low cost, miniaturization, and adaptability to the point-of-care (POC). Nonetheless, most EC sensors are specialized to a particular target, and there remains a need for a robust EC biosensor platform for the multitude of biomarkers that are not EC-active, do not undergo enzymatic conversion, or are not suited for potentiometry [1,2]. While aptamer-based EC sensors have been proven for sensing in living animals with temporal resolution of a few seconds [3], most method development has been target-focused, lacking generalizability [4]. Presently, the clinical EC toolbox is a conglomerate of targeted methods, and there is a pressing need to develop a single EC platform amenable to rapid, generalizable, quantitative readout of multiple classes of clinically relevant targets. A direct, generalized EC sensing approach with minimal added reagents or amplification steps is preferred [5,6]. Our group has been working to address this need and expand to more analyte classes for several years, and in 2019 we designed a versatile DNA-nanostructure architecture attached to gold electrode surfaces [6]. In this work, we will discuss our efforts to expand the generalizability of our sensor platform, chiefly through custom synthesis of varied DNA-analyte bioconjugates to incorporate within the DNA-nanostructure, specifically DNA-peptide and DNA-small molecule conjugates. Using the same DNA nano-architecture, sensors have been validated in 98% human serum for a variety of targets, several encompassing the human clinical range—a peptide drug (exendin-4) [7], a larger protein (creatine kinase), and smaller molecules or steroid hormones (testosterone, estradiol, progesterone, cortisol). Overall, this new DNA nanostructure platform provides a generalizable sensor with minimal workflow, direct-readout, and the capability to expand EC sensing to a wide variety of clinically important analytes. These sensors can measure antibodies directly without any reagent addition, and the small-molecule or peptide sensors require just a two-step workflow. While the workflow is minimal, the EC measurements benefit from well-controlled solution pH, ionic strength, etc. As such, automated fluidic handling can enhance the user-friendliness of the sensors while maintaining measurement quality. We will also discuss several advancements in automating microfluidic flow control, leveraging digital circuit analogies to develop on-chip pneumatic circuits [8,9]. Using devices fabricated by inexpensive, resin-based 3D printers, we have developed robust pneumatic oscillators that can control on-chip valves for pumping solutions to the EC sensors. The oscillators are automated and tunable from 0.5 to 100 Hz and can pump multiple solutions on microdevices with only a single vacuum input line. Antibody reagents and samples can be mixed automatically then introduced to the electrode, and buffer washes can be included to improve measurement consistency. Ultimately, by integrating this automated microfluidic control with our generalizable EC sensors in the future, many different analytes should be measurable consistently and in a user-friendly manner.

Leakage Fault Diagnosis of Two Parallel Cylinders in Pneumatic System with a Minimal Number of Sensors

The low investment cost is one of the core competitiveness advantages of pneumatic power systems. With increasingly pressing intelligent manufacturing, it is meaningful to investigate the feasibility of implementing fault diagnoses of pneumatic systems with a minimal number of low-cost sensors. In this study, a typical pneumatic circuit with two parallel-installed cylinders is taken as an example. The pressure, flow rate, and exergy data collected from upstream sensors are used for diagnosing the leakage faults in two downstream cylinders with the help of different machine learning methods. The features of data are extracted with stacked auto-encoders. Gaussian process classifier, support vector machine, and k-nearest neighbor are used for classifying faults. The results show that it is feasible to detect and diagnose downstream multi-faults with one or two upstream sensors. In terms of the working conditions presented in this study, the average accuracy of diagnosis with exergy data is the highest, followed by flow-rate data and pressure data. The support vector machine performs the best among the three machine learning methods.

Optimal design of automatic assembly system for bolts and nuts in sets

Due to the slow assembly speed, large consumption of compressed air, and low qualification rate, the automatic assembly system for bolts and nuts in sets needs to be optimized urgently. The performance requirements of the system were analyzed, and the evaluation indexes of the system were proposed. Since the efficiency of the system mainly depends on the pneumatic components, the optimization work focuses on the pneumatic circuit. Parameters of the pneumatic circuit and pipeline were obtained through modeling and simulation. After parameter optimization, prototype test results have shown that the assembly speed and qualification rate of the optimized system is increased by 47.83% and 7.77%, respectively, while the air consumption is reduced by 23.39% compared with the original system.

Pneumatic computers for embedded control of microfluidics.

Alternative computing approaches that interface readily with physical systems are well suited for embedded control of those systems. We demonstrate finite state machines implemented as pneumatic circuits of microfluidic valves and use these controllers to direct microfluidic liquid handling procedures on the same chip. These monolithic integrated systems require only power to be supplied externally, in the form of a vacuum source. User input can be provided directly to the chip by covering pneumatic ports with a finger. State machines with up to four bits of state memory are demonstrated, and next-state combinational logic can be fully reprogrammed by changing the hole-punch pattern on a membrane in the chip. These pneumatic computers demonstrate a framework for the embedded control of physical systems and open a path to stand-alone lab-on-a-chip devices capable of highly complex functionality.

BIO24: Reducing Risk of Barotrauma in Donor Lungs During Transport

Background: The journey donor lungs take after being procured on the way to the recipient often involves the use of air transportation, subjecting the organ to different altitudes. During takeoff and at cruising altitudes, decreased atmospheric pressures lead to increased relative airway pressures, increasing the risk for barotrauma. While this may be due to underinflation during procurement, the risk of barotrauma likely still exists given the subjective nature of the process and variability between surgeons and centers. Methods: Using porcine lungs (n=3), the airway pressure of donor lungs in simulated flight takeoff and landing was actively controlled using a novel preservation system and measured with calibrated gauges. Lungs were prepared using 2L preservation solution at 4°C in the inner bag and 2L saline at 4°C in the middle bag. A modified 3 bag system allowed for the trachea to be connected to pneumatic circuit designed to maintain target airway pressures of 12-15 cmH2O per the ISHLT consensus statement. Parameters for simulated takeoff and landing (1,000ft/min), peak altitude (8,000ft), and time at peak altitude (6 hours) were chosen to reflect the worst-case scenario. Results: All airway pressures remained within 12-15 cmH2O (±1 cmH2O) following a maximum of 5-minute stabilization time after transitioning between stable ambient pressures. This demonstrates the ability of the system to maintain airway pressures within this range at pressures up to 8000ft (worst-case for pressurized aircraft cabin). During simulated takeoff and landing scenarios, all airway pressures remained within 10-20 cmH2O at 1000ft. Without active pressure control, airway pressures may increase above 30 cmH2O. Conclusions: Airway pressures during flight remained within the intended range using a novel preservation system for donor lungs. Without active control using the systems, airway pressure of lungs are subjected to unsafe levels, which may lead to suboptimal postoperative outcomes.

Design and research on pneumatic system of tire wheel hub matching machine

With the increasingly fierce competition in the automotive industry, the requirements for the automobile wheel hub assembly line weregetting higher and higher, and the matching machine has become an indispensable part of the assembly line. In this paper, the structure of pneumatic drive and servo drive was adopted by the tire wheel hub matching machine, which ensured the production rhythm and the matching accuracy requirements. According to the overall index requirements of the automatic matching machine,the pneumatic system schematic diagram was determined by the detailed research and comparison of the principle and system composition of the representative pneumatic circuit.

Пневмоэлектрические регуляторы на основе эффекта силового действия струи

The paper considers issues of design and development of pneumoelectric controllers based on compensation of the jet power action pneumatic moment by the magnetoelectric moment. The main controller elements include magnetoelectric galvanometer, sensitive element (flat plate), as well as pneumatic, optical and electrical circuits. Pneumoelectric controllers are characterized by high sensitivity and speed. Schemes of inkjet-photocompensation proportional, proportional-integral, proportional-integral-differential, semi-proportional controllers and of the preliminary and differentiation units are provided.

Analysis and modelling of the dynamic stiffness up to 400 Hz of an air spring with a pipeline connected to a reservoir

The present research addresses the dynamic behaviour of an air spring with a pipeline connected to a reservoir in a frequency range up to 400 Hz, in which structure-borne vibration transmission may occur due to both the structural behaviour of the bellows and fluid dynamics in the pneumatic circuit of the suspension. Based on experimental results, three frequency ranges are distinguished where different resonances of the suspension appear: low (up to 30 Hz) due to the air flow between the bellows and the surge reservoir, intermediate (30–150 Hz) due to the formation of standing waves in the pipeline and high (beyond 150 Hz) due to the structural dynamics of the bellows. A novel modelling technique to predict the dynamic behaviour of the pneumatic system in all these frequency ranges is presented and validated: this consists of an enhanced Finite Element Model (FEM) considering the structural properties of the bellows and the effect of pressurised air in the bellows and in the reservoir, coupled to a model of fluid exchange between the two main air volumes which is defined using a VUFLUIDECH user subroutine developed in ABAQUS. The study focusses on the axial dynamic stiffness of the pneumatic suspension, which plays a key role in determining the transmissibility of the suspension. However, the mathematical model introduced in the paper is capable of predicting also the vibration modes of the suspension in shear and rotation, which may be relevant in some applications, e.g. when air springs are used in vehicle suspensions.