Pneumatic Circuit Research Articles

Differential Pressure Airtight Intelligent Gauge for Locomotive Electropneumatic Valve

The hermeticity of the electropneumatic valve directly decides the availability of locomotive control. By far, some test methods at home and abroad effectively can detect its hermeticity but at the cost of lowering automaticity, detection efficiency and accuracy, as well as undermining environmentally friendly and adding overhead. In view of the above defects, we propose the differential pressure detection to achieve the hermeticity detection on the electropneumatic valve. Aerodynamic optimization and model analysis helps design a differential pressure hermeticity gauge with MSP430 as the control core. Composed of pneumatic circuit, valve body fixture and control circuit, this gauge can automatically complete the whole hermeticity detection on electropneumatic valve. A system test proves that the gauge can quantitatively and accurately reflect the spillage and the leakage rate and realize the automation of the valve hermeticity detection. As it features low power consumption, fast detection, system stability, etc., it can effectively fill the gaps of the existing technologies. In this sense, it indeed has a good practicality and promising prospect. (Wei et al., 2016)

Study on Nonlinear Dynamic Optimization of Bridge Type Pneumatic Energy Saving Circuit

Study on Nonlinear Dynamic Optimization of Bridge Type Pneumatic Energy Saving Circuit

Sensor Based Portable Tremor Suppression Device for Stroke Patients

Objective: Tremor is a clinically depicted commonly encountered neurological disorder which results after a stroke or brain injury like Parkinson's disease which causes rhythmic and reflex oscillatory movement of a body, particularly upper arm, which is difficult to diagnose and manage. Tremor is influenced by Physiological and Psychological factors which can affect any age group specifically in middle age and older persons. The modern treatment facilities and features available are very expensive and unreachable for rural people. Hence there arises a necessity to develop a portable device to overcome such situations. Methods: This paper introduces a portable and wearable device using accelerometer sensor assisted with pneumatic mechanism for tremor suppression in the upper arm. This portable device may help to suppress tremor and improve muscle control and coordination in the upper arm. Once the device is connected with the patients arm, the pneumatic circuit supplies required air through the hand cuff to keep the arm on control with reference to the signal obtained from the accelerometer sensor. The results: The performances of the device are measured in three different stages say before inflation, during partial inflation and full inflation. The results depicts 30% of improvement in tremor suppression at three different levels of tremor occurrence which is measured in terms of voltage between 1.6 and 2V at high, medium and low levels at different time intervals with frequency <10Hz. Conclusion: This device is a cost effective and portable closed loop system which is exclusively designed to reduce the tremor without affecting the upper limb voluntary movements.

Energy efficiency control of pneumatic actuator systems through nonlinear dynamic optimization

Abstract As one of the most widely used power sources in the engineering field, compressed air is especially common in industrial applications. In a traditional pneumatic circuit, a three-position five-way valve is used to control the air inlet and exhaust with a single pressure, which has low efficiency. This paper proposed a novel bridge-type circuit with variable pressure control using four on-off valves to improve the energy efficiency of compressed air for pneumatic actuators. The key idea of the method was to use air expansion energy to do work. Reducing the volume of consumed air was the goal, and a numerical method was presented to calculate the optimal on-off time sequence of the four valves using nonlinear dynamic optimization. The sequence was obtained based on the combination of a finite element polynomial configuration method and a reduced space sequential quadratic programming algorithm. Then, experimental validation was conducted to illustrate the energy efficiency, including pneumatic cylinder motion test under different conditions. Compared with the traditional circuit, the experimental results show that the bridge-type circuit put forward by this paper can significantly improve the energy efficiency of pneumatic driving systems by 50–70%. Additionally, the bridge-type circuit allows the piston to move smoothly to the end of the stroke, which can take the place of the function of cushion component and speed control valve of the traditional circuit.

CONSTRUCTION OF EQUATIONS OF MOTION OF MULTIBODY SYSTEMS AND COMPUTER MODELING

Urgency of the research. Computer models mean new quality in the knowledge process. Using a computer model, the properties of the subject under investigation can be tested under different operating conditions. By experimenting with a com-puter model, we learn about the modelled object. We can test different machine variants without having to produce and edit prototypes. Target setting. The development of computer technology has expanded the possibility of solving mathematical models and allowed to gradually automate the calculation of mathematical model equations. It is necessary to insert appropriate inputs of the mathematical model and monitor and evaluate the output results through the computer output device The target was to describe the mathematical apparatus required for mathematical modeling and subsequently to compile a model for computer modeling. Actual scientific researches and issues analysis. When formulating a mathematical model for a computer, the laws and the theory we use are always valid under more or less idealized conditions, and operate with fictitious concepts such as, material point, ideal gas, intangible spring, and the like. However, with these simplifications, we describe a realistic phenomenon where the initial assumptions are only met to a certain extent. In order for the results not to be different from the modeled reality, it is to be assumed that a good computer model arises gradually, by verifying and modifying it, which is one of the advantages of MSC Adams. Uninvestigated parts of general matters defining. The question of building a real manipulator model. Based on the above simulation, it is possible to build a real model. The research objective. Using MSC Adams to simulate multiple body systems and verify its suitability for simulating ma-nipulator and robot models. In various versions of the assembled model we can monitor its behavior under different operating conditions. The statement of basic materials. In computer simulation, MSC Adams-View is used to simulate mechanical systems. It has an interactive environment for automated dynamic analysis of parameterized mechanical systems with an arbitrary struc-ture of rigid and flexible bodies with geometric or force joints, in which act gravity, inertia, experimentally designed contact, friction, aerodynamic, hydrodynamic or electromechanical forces and have integrated control, hydraulic, pneumatic or elec-tromechanical circuits. Conclusions. Working with a mathematical model on a computer opens space for specific synthesis of empirical and ana-lytical method of scientific knowledge. Working with the computer model carries the characteristic features of classical experi-mentation. It represents a qualitatively new way of solving tasks that can not be experimented with on a real object. The result is the equivalence of the computer model and the object being investigated with the features and expressions chosen as essen-tial, with accuracy sufficient to the exact purpose.

Approach of Flow Control Around Unmanned Underwater Robot

Abstract The development of a prototype of an underwater robot with a variable geometry of the body is a major complex task, including a whole series of tasks of a scientific, technical, engineering and applied nature, and the creation of new automatic systems for managing it. The creation of such a robot will ensure its high autonomy and maneuverability. In this paper, the development of a solid model of a biomimetic robot hybrid and AUV with a variable geometry of the hull is presented. Also presented is a basic pneumatic circuit integrated into the robot body, which drives the pneumatic muscles fixed to the ribs of the robot’s robust body. The experimental part includes the investigation of the vertical and horizontal components of the deformation of the walls of the shell, depending on the pressure supplied by the pneumatic system to the pneumatic cusps.

The Intelligence Braking and the Pneumatic Automatic Braking System for Autonomous Vehicles

Autonomous driving is the main development direction of the automobile in the present and the future Intelligencebraking is the key assembly to realize autonomous driving The pneumatic brake system is the principle part of commercial vehicle to brake In order to meet the requirements of autonomous driving this paper proposed the concept of intelligent braking and pneumatic automatic braking and then a kind of pneumatic automatic braking circuit is designed The pressure change rate is used as a new index to evaluate automatic braking and control This study provides a new theoretical basis for design and application of the pneumatic braking system

Design of a Soft Robot with Multiple Motion Patterns Using Soft Pneumatic Actuators

Soft robots are made of soft materials and have good flexibility and infinite degrees of freedom in theory. These properties enable soft robots to work in narrow space and adapt to external environment. In this paper, a 2-DOF soft pneumatic actuator is introduced, with two chambers symmetrically distributed on both sides and a jamming cylinder along the axis. Fibers are used to constrain the expansion of the soft actuator. Experiments are carried out to test the performance of the soft actuator, including bending and elongation characteristics. A soft robot is designed and fabricated by connecting four soft pneumatic actuators to a 3D-printed board. The soft robotic system is then established. The pneumatic circuit is built by pumps and solenoid valves. The control system is based on the control board Arduino Mega 2560. Relay modules are used to control valves and pressure sensors are used to measure pressure in the pneumatic circuit. Experiments are conducted to test the performance of the proposed soft robot.

Research of Pneumatic Distributors for Launcher of Unmanned Aerial Vehicle (UAV)

Abstract The test stand for investigations of flow characteristics of pneumatic distributor has been presented in this paper. This test stand has been composed as requirements include in standard PN-92/M-73763. The results of experimental and simulation investigations for standard five ways and two position pneumatic distributor have been presented. In simulations have been used CFD of SolidWorks Flow Simulation application. Flow characteristic of pneumatic distributor is necessary for design process of special pneumatic circuits of UAV launchers. CFD methods allow specify flow characteristics. Simulation research allow effective pneumatic components modification, whose used of special pneumatic circuits of UAV launchers. Results of experimental and simulation investigations were analyzed and compared.

Design and Dynamic Model of a Frog-inspired Swimming Robot Powered by Pneumatic Muscles

Pneumatic muscles with similar characteristics to biological muscles have been widely used in robots, and thus are promising drivers for frog inspired robots. However, the application and nonlinearity of the pneumatic system limit the advance. On the basis of the swimming mechanism of the frog, a frog-inspired robot based on pneumatic muscles is developed. To realize the independent tasks by the robot, a pneumatic system with internal chambers, micro air pump, and valves is implemented. The micro pump is used to maintain the pressure difference between the source and exhaust chambers. The pneumatic muscles are controlled by high-speed switch valves which can reduce the robot cost, volume, and mass. A dynamic model of the pneumatic system is established for the simulation to estimate the system, including the chamber, muscle, and pneumatic circuit models. The robot design is verified by the robot swimming experiments and the dynamic model is verified through the experiments and simulations of the pneumatic system. The simulation results are compared to analyze the functions of the source pressure, internal volume of the muscle, and circuit flow rate which is proved the main factor that limits the response of muscle pressure. The proposed research provides the application of the pneumatic muscles in the frog inspired robot and the pneumatic model to study muscle controller.

A Model Hand Prosthesis Controlled by Foot and Toe Movements

An approach to controlling hand prostheses using foot and toe movements is proposed. Construction of a model hand prosthesis with independent finger movements is described. A wireless remote control system for the prosthesis by tactile insoles fitted into the shoes is presented. Transfer parameters are selected by a synthesis based on the required final foot positions in the input and output sides of the system. Pneumatic bellows parameters, bracing spring stiffness, and pressure in the pneumatic circuit are selected on the basis of size restrictions and forces on the fingers. The study was supported by the Russian Foundation for Basic Research (Grant No. 16-08-00305A).

Flotation plant-wide control strategy evaluated on hybrid pilot plant

In this work, the implementation and use of a metallurgical simulator for a flotation plant, including rougher-cleaner-scavenger, RCS, is presented. The simulator can be fed by the user with input operating and metallurgical variables generated off line or in a hybrid manner. In the last case, the operating variables of all circuits are read from instrumentation installed in the pilot plants and combined with virtual variables, generated by the user, to run the metallurgical simulator in order to predict the characteristics of each virtual stream. The pilot plant is located at the Process Control Laboratory and includes a three pneumatic cells rougher circuit, a flotation column and a two pneumatic cell scavenger circuit. The regrinding and classification stages are simulated by using models based on literature.An expert control system is built in order to find out best operating points, in the sense of metallurgical results, mainly Cu global recovery and specified characteristics of the final concentrate. The expert system administrates the set points of the controllers of the operating variables of the plant (froth depths and air flow rates). The control strategy maximizes the rougher Cu recovery subject to the condition that the produced rougher concentrate can be adequately processed in the cleaner, regrinding, classification and scavenger circuits. To achieve this, the quality of the rougher concentrate (Cu grade over a given value and solid mass flow rate under a given value) is monitored jointly with the degree of saturation of manipulated variables in the rest of the circuits, the quality of the final concentrate and the recovery of the scavenger circuit. The result is to find out how to operate the whole plant to obtain both a final concentrate meeting specifications and the maximum Cu global recovery of the plant. Several examples are discussed. Copyright © 2017 IF AC.

Discrimination of bacteria by rapid sensing their metabolic volatiles using an aspiration-type ion mobility spectrometer (a-IMS) and gas chromatography-mass spectrometry GC-MS

The objective of our study was to investigate whether one may quickly and reliably discriminate different microorganism strains by direct monitoring of the headspace atmosphere above their cultures. Headspace samples above a series of in vitro bacterial cultures were directly interrogated using an aspiration type ion mobility spectrometer (a-IMS), which produced distinct profiles (“fingerprints”) of ion currents generated simultaneously by the detectors present inside the ion mobility cell. Data processing and analysis using principal component analysis showed net differences in the responses produced by volatiles emitted by various bacterial strains. Fingerprint assignments were conferred on the basis of product ion mobilities; ions of differing size and mass were deflected in a different degree upon their introduction of a transverse electric field, impacting finally on a series of capacitors (denominated as detectors, or channels) placed in a manner analogous to sensor arrays.Three microorganism strains were investigated – Escherichia coli, Bacillus subtilis and Staphylococcus aureus; all strains possess a relatively low pathogenic character. Samples of air with a 5 cm3 volume from the headspace above the bacterial cultures in agar growth medium were collected using a gas-tight chromatographic syringe and injected inside the closed-loop pneumatic circuit of the breadboard a-IMS instrument model ChemPro-100i (Environics Oy, Finland), at a distance of about 1 cm from the ionization source. The resulting chemical fingerprints were produced within two seconds from the moment of injection. The sampling protocol involved to taking three replicate samples from each of 10 different cultures for a specific strain, during a total period of 72 h after the initial incubation – at 24, 48 and 72 h, respectively. Principal component analysis (PCA) was used to discriminate between the IMS fingerprints. PCA was found to successfully discriminate between bacteria at three levels in the experimental campaign: 1) between blank samples from growth medium and samples from bacterial cultures, 2) between samples from different bacterial strains, and 3) between time evolutions of headspace samples from the same bacterial strain over the 3-day sampling period. Consistent classification between growth medium samples and growth medium inoculated with bacteria was observed in both positive and negative detection/ionization modes.In parallel, headspace air samples of 1 dm3 were collected from each bacterial culture and loaded onto Tenax™-Carbograph desorption tubes, using a custom built sampling unit based on a portable sampling pump. One sample was taken for each of 10 different cultures of a strain, at 24, 48 and 72 h after the initial incubation. These adsorption tubes were subsequently analyzed using thermal desorption – gas chromatography – mass spectrometry (TD-GC-MS). This second dataset was intended to produce a qualitative analysis of the volatiles present in the headspace above the bacterial cultures.

Design and Simulation of a New Hammer Source Control System

There are a series of problems in using explosive source in land oil seismic exploration at present. Aiming at this problem, a new hammer source system which can replace explosive source was proposed. Function of the hammer source system was analyzed and a typical pneumatic control circuit was designed. With the advantages of strong impact, high speed and small gas consumption, quick air exhaust impact cylinder was used in the hammer source system. An electronic control system was designed based on PLC, including the hardware component and software design. The pneumatic control system was simulated and analyzed in AMESim, and the results showed that the system can meet the design requirements, provide a reference for engineering application.

Optimal hybrid scheme of dynamic neural network and PID controller based on harmony search algorithm to control a PWM-driven pneumatic actuator position

In this paper, the position of a pulse width modulation (PWM)-driven pneumatic actuator has been controlled using a dynamic neural network (DNN) and Proportional Integral Derivative (PID) controller. The harmony search algorithm (HSA) has been used to unravel the optimization problem. The DNN controller is optimally designed to control the position of the actuator. As to the performance of the PID controller, it can assist the DNN controller to give better results. Therefore, an optimal hybrid scheme with both DNN and PID controllers based on HSA is suggested. A pneumatic circuit containing a fast-switching valve is used to reduce the complexity of the PWM-driven servo pneumatic system along with its cost price.

The synthesis of structure and parameters of energy efficient pneumatic actuator

It is known that compressed air is one of the most expensive energy carriers while a discrete pneumatic actuator with throttle braking of operating unit possesses a rather low degree of energy perfection. Present work posed and solved the problem on the isolation of all unproductive power consumption in the pneumatic actuator. Such power expenditures include losses due to the incompleteness of air expansion in the working cavity, losses in the dead space, losses for throttling, additional losses for the fixation of operating unit, and the losses, related to the work to eject compressed air from the exhaust cavity. Authors designed the circuits for actuators, as well as the principles of their operation, which make it possible to maximally decrease such unproductive power consumption. One more essential shortcoming in the pneumatic actuators with traditional circuit of throttle braking is a rather limited level of inertia load, within which the actuator remains operational. A cardinal solution for these problems in present work is achieved due to the transition from the circuits of throttle braking, which are quite formally transferred from hydraulic drive technique, to the circuits of braking through a change in the structure of commutation connections. Due to this, it was possible for each phase of the motion of operating unit to enable the most rational commutation relations, which allowed us to attain maximum realization of the working capacity of compressed air in pneumatic actuator and to achieve the most preferable form in the transient process. The latter made it possible to substantially increase inertia loads, at which the actuator remains operational. Pneumatic circuits based on the commercially available pneumatic equipment are proposed, which realize these principles. A mathematical model in the dimensionless form with the isolation of criteria of dynamic similarity is developed. Based on this, a region of the rational utilization of the proposed actuators is determined in the plane of criteria of dynamic similarity; and one of the problems is solved on the parametric synthesis in the form of selecting a diameter of cylinder, which provides for the work of actuators in the zone of the most effective energy saving. Authenticity of the obtained theoretical results is confirmed by the oscillograms of transient process in the experimental sample of energy-saving pneumatic actuator.

Fully chip-embedded automation of a multi-step lab-on-a-chip process using a modularized timer circuit.

For highly-integrated microfluidic systems, an actuation system is necessary to control the flow; however, the bulk of actuation devices including pumps or valves has impeded the broad application of integrated microfluidic systems. Here, we suggest a microfluidic process control method based on built-in microfluidic circuits. The circuit is composed of a fluidic timer circuit and a pneumatic logic circuit. The fluidic timer circuit is a serial connection of modularized timer units, which sequentially pass high pressure to the pneumatic logic circuit. The pneumatic logic circuit is a NOR gate array designed to control the liquid-controlling process. By using the timer circuit as a built-in signal generator, multi-step processes could be done totally inside the microchip without any external controller. The timer circuit uses only two valves per unit, and the number of process steps can be extended without limitation by adding timer units. As a demonstration, an automation chip has been designed for a six-step droplet treatment, which entails 1) loading, 2) separation, 3) reagent injection, 4) incubation, 5) clearing and 6) unloading. Each process was successfully performed for a pre-defined step-time without any external control device.

Methodology for manipulation of Karnaugh maps designing for pneumatic sequential logic circuits

This paper presents an alternative way to use the Karnaugh maps, which minimises logical conditions used for ON/OFF control, in either pneumatic and electro pneumatic circuits. In the last case, the methodology allows the control of the circuit through a programmable logic controller (PLC). In this kind of processes, controlling pneumatic cylinders is a problem that not only depends on the state of the information present but also in terms of knowledge of past actions. In practice, ensuring a series of sequential movements in an automatic cycle is to find the set of equations that should be executed to ensure the realisation of the desired sequence. It means therefore that the equations that will allow the movements of each cylinder are functions only of two types of input variables, the position of each cylinder and if necessary, memory variables. One of the major merits that arise from the use of the proposed method is the simplicity of obtaining electrical schematic command circuit. The proposed methodology ensures not only the desired sequential cycle, as well as the minimisation of the variables necessary for control commands.

Evolutionary Algorithms for Programming Pneumatic Sequential Circuit Controllers

Sequential actuation of pneumatic cylinders is a common form of automation in small and medium scale industries. By changing such actuation sequences to suit the different products being processed, flexible automation can be economically realized. However, changing the actuation sequence involves manually reprogramming Programmable Logic Controllers (PLC), which consumes time and hinders the implementation of flexible automation. This paper presents a novel methodology to automatically program PLCs by evolving logic equations using Genetic Algorithm and Genetic Programming for the desired actuation sequence. Case studies have been presented to demonstrate the possibility of using the proposed methodology to reliably implement flexible automation.

Methodology for manipulation of Karnaugh maps designing for pneumatic sequential logic circuits

Methodology for manipulation of Karnaugh maps designing for pneumatic sequential logic circuits