基于FluidSIM Pneumatics软件的气动及机电一体化设计

气压传动及机电一体化系统设计在现代机械设计中占有很重要的地位。介绍德国FESTO公司开发的FluidSIMPneumatics软件。对该软件的主要技术要求、功能以及气压传动与机电一体化系统的设计方法作了详细的介绍。它为学习者和工程技术人员提供了分析、研究、设计。

Real Gas Effects on Charging and Discharging Processes of High Pressure Pneumatics

The high pressure pneumatic system has been applied to special industries. It may cause errors when we analyze high pressure pneumatics under ideal gas assumption. However, the real gas effect on the performances of high pressure pneumatics is seldom investigated. In this paper, the real gas effects on air enthalpy and internal energy are estimated firstly to study the real gas effect on the energy conversion. Under ideal gas assumption, enthalpy and internal energy are solely related to air temperature. The estimation result indicates that the pressure enthalpy and pressure internal energy of real pneumatic air obviously decrease the values of enthalpy and internal energy for high pressure pneumatics, and the values of pressure enthalpy and pressure internal energy are close. Based on the relationship among pressure, enthalpy and internal energy, the real gas effects on charging and discharging processes of high pressure pneumatics are estimated, which indicates that the real gas effect accelerates the temperature and pressure decreasing rates during discharging process, and decelerates their increasing rates during charging process. According to the above analysis, and for the inconvenience in building the simulation model for real gas and the difficulty of measuring the detail thermal capacities of pneumatics, a method to compensate the real gas effect under ideal gas assumption is proposed by modulating the thermal capacity of the pneumatic container in simulation. The experiments of switching expansion reduction （SER） for high pressure pneumatics are used to verify this compensating method. SER includes the discharging process of supply tanks and the charging process of expansion tank. The simulated and experimental results of SER are highly consistent. The proposed compensation method provides a convenient way to obtain more realistic simulation results for high pressure pneumatics.

Nonlinear Characteristic Analysis of Gas-Interconnected Quasi-Zero Stiffness Pneumatic Suspension System:A Theoretical and Experimental Study

Because of significantly changed load and complex and variable driving road conditions of commercial vehicles,pneumatic suspension with lower natural frequencies is widely used in commercial vehicle suspension system.How ever,traditional pneumatic suspension system is hardly to respond the greatly changed load of commercial vehicles To address this issue,a new Gas-Interconnected Quasi-Zero Stiffness Pneumatic Suspension(GIQZSPS)is presented in this paper to improve the vibration isolation performance of commercial vehicle suspension systems under frequent load changes.This new structure adds negative stiffness air chambers on traditional pneumatic suspension to reduce the natural frequency of the suspension.It can adapt to different loads and road conditions by adjusting the solenoid valves between the negative stiffness air chambers.Firstly,a nonlinear mechanical model including the dimensionless stiffness characteristic and interconnected pipeline model is derived for GIQZSPS system.By the nonlinear mechanical model of GIQZSPS system,the force transmissibility rate is chosen as the evaluation index to analyze characteristics.Furthermore,a testing bench simulating 1/4 GIQZSPS system is designed,and the testing analysis of the model validation and isolating performance is carried out.The results show that compared to traditional pneumatic suspension,the GIQZSPS designed in the article has a lower natural frequency.And the system can achieve better vibration isolation performance under different load states by switching the solenoid valves between air chambers.

Outcomes and variables that impact pneumatic retinopexies

●AIM:To evaluate the efficacy of pneumatic retinopexy(PR)in patients undergoing PR as primary treatment for rhegmatogenous retinal detachment(RRD)and analyze the factors associated with success and failure in the studied population.●METHODS:A retrospective chart review was done of patients with RRD treated with PR as primary management method treated at New York Eye and Ear Infirmary of Mount Sinai between January 2017 and December 2021.Primary outcome measured success or failure of PR.Secondary outcome measured best corrected visual acuity(BCVA)after PR.A separate risk analysis was done to identify and stratify risks associated with success and failure of PR.●RESULTS:A total of 179 eyes from 179 patients were included for final analysis.The 83 patients(46.37%)achieved anatomical reattachment of the retina after primary PR with no need for additional surgery.The 96 patients(53.63%)had a failed primary PR and required a PPV and 6 of them required pars plana vitrectomy(PPV)with scleral buckle(SB).In total,19 cases(10.61%)were done as temporizing pneumatics,18(94.74%)underwent PPV,and 1(5.26%)did not require further intervention.The visual acuities at postoperative month 1(POM1)for patients who underwent primary PR successfully and for those that underwent PPV after,were 0.58(20/80)and 1.03(20/200)respectively.Patients who met Pneumatic Retinopexy Versus Vitrectomy for the Management of Primary Rhegmatogenous Retinal Detachment Outcomes Randomized Trial(PIVOT)criteria had a statistically significant decreased risk of primary PR failing(hazard ratio 0.29,P=0.00).Majority of missed or new breaks were found superotemporally.●CONCLUSION:PR is a good treatment option for treating RRDs in patients that meet PIVOT criteria and can be conducted as a temporizing measure.PIVOT criteria and fovea on status decrease the risk of PR failure.

Gastroesophageal reflux following peroral endoscopic myotomy for achalasia:Bumps in the road to success

Achalasia can significantly impair the quality of life.The clinical presentation typically includes dysphagia to both solids and liquids,chest pain,and regurgitation.Diagnosis can be delayed in patients with atypical presentations,and they might receive a wrong diagnosis,such as gastroesophageal reflux disease(GERD),owing to overlapping symptoms of both disorders.Although the cause of achalasia is poorly understood,its impact on the motility of the esophagus and gastroesophageal junction is well established.Several treatment modalities have been utilized,with the most common being surgical Heller myotomy with concomitant fundoplication and pneumatic balloon dilatation.Recently,peroral endoscopic myotomy(POEM)has gained popularity as an effective treatment for achalasia,despite a relatively high incidence of GERD occurring after treatment compared to other modalities.The magnitude of post-POEM GERD depends on its definition and is influenced by patient and procedure-related factors.The longterm sequelae of post-POEM GERD are yet to be determined,but it appears to have a benign course and is usually manageable with clinically available modalities.Identifying risk factors for post-POEM GERD and modifying the POEM procedure in selected patients may improve the overall success of this technique.

Re-Densification Effect of Pressure-Injected Peptide-Hyaluronic Acid Combination on Male Androgenic Alopecia

Introduction: Mechanism of male androgenic alopecia (MAGA) is complex and leads to an excessive hair shedding and decreased hair density. Oral, topical, and injectable autologous treatments demonstrate ability to stimulate hair re-growth, but the response is suboptimal or plateaus off. Synthetic combination of the peptide complex and hyaluronic acid (P-HA) demonstrated hair regrowth in alopecia patients. Electronically-operated pneumatic injections (EPI) generate micro-trauma in the dermis and under wound-healing conditions may enhance regeneration effect of P-HA. Methods: Subjects seeking improvement of their male pattern hair loss (Hamilton-Norwood type 2-4) received the P-HA treatments through EPI. The course included 4 treatments every two weeks over the 8-week period. In 6 months, the hair growth was assessed comparative to baseline by global clinical photography and digital phototrichograms. The treatment safety and tolerability were documented through the whole study period. Results: Twelve men (30-45 years old) completed the treatment course with high tolerability and without adverse events. Post-treatment assessment of the previously bald areas showed improved coverage on the clinical photographs. The phototrichograms demonstrated statistically significant increase in terminal hair density by 36%, cumulative hair thickness by 37%, and follicular units by 20%;all contributing to a 38% increase in cumulated hair density (all p Conclusion: Electronic pneumatic injections are well tolerated and can be safely used for the needle-free administration of the peptide-hyaluronic acid combination in MAGA therapy. We achieved significant hair re-densification in the balding scalp. The exact role of the EPI-induced impact in the hair re-growth mechanism remains to be ascertained. .

Modeling and Simulation of the Characteristics of Pneumatic Cushion Cylinders

The analysis of the characteristics of the cushion process of the pneumatic cushion cylinder is presented, and the nonlinear model of pneumatic cushion cylinders is built in the form of nonlinear differential equations. Besides, through the simulation of the pressure in the cushion chamber, the characteristics of the pneumatic cushion cylinder are obtained, which helps to understand the performance of the pneumatic cushion cylinder and improve or design the better cushion structure.

基于学习生物体运动的一种人工筋驱动器的研究

本文从仿生学的观点，学习生物体的原理，研究微型机器人的机构和控制问题，是开发微型机电系统的一个关键技术。介绍了生物体运动的基本特征，并从学习生物体运动的设计原理出发，对一种具有与人体肌肉类似特性的空气压人工筋进行了实验研究，表明它有可能成为一种新颖的柔性进机器人的驱动器，在医疗及微小空间作业的特种机器人中获得应用。

Study on Quality Improvement of Flue-cured Tobacco by Threshing and Pneumatic Separation

This study was conducted to further classify threshed strips, so as to broaden the usable range of raw material and facilitate the effective utilization of to- bacco resource. During the threshing and redwing process, various process param- eters including the rotating speeds of threshing drums of threshing machioe, draught fans and fling drums were scientifically and rationally set according to the actual quality of the raw material. According to the characteristic that strips with close in- herent quality have basically the same specific gravity and leaf thickness, the strips from each discharge hole were accurately evaluated, and classified, followed by redrying and packaging. The results showed that the threshing and separating pro- cedure could improve the separating effect and precision according to tobacco qual- ity, so as to satisfy the separation and classification requirements for tobacco.

A Kind of PWM Pneumatic Servo Control System——Modulation Methods and Dynamic Responses

Vibrations or dither's are features of the PWM servo control system in their steady outputs. On the grounds of analyses and experiments of a PWM pneumatic servo control system, the paper puts forward four varieties of PWM modulation methods, and concludes on the relationship between dithers and the different methods, and then discusses the influence of friction to the dithers. Results from experiments regarding the dynamic and static responses on the given system support the theories presented.

Property Analyses and Experiment Studies of a Kind of PWM System

The properties and the design of PWM systems are discussed. The relations among the orifice areas of the valves, initial times and the rate of piston areas are deduced. Also a PWM system is designed and some experiments are done. The experiment results agree with those of theory analyses. It can be shown that the relations are correct and the conclusion of theory analyses is reasonable.

Gas Leakage Detection and Pressure Difference Identification by Asymmetric Differential Pressure Method

Currently,the measurement methods for pneumatic system leakage include bubbling,ultrasonic,and pressure detection methods.These methods are sensitive to high-precision sensors,long detection times,and stable external environments.The traditional differential pressure method involves severe differential pressure fluctuations caused by environmental pressure fluctuations or electromagnetic noise interference of sensors,leading to inaccurate detection.In this paper,a differential pressure fitting method for an asymmetric differential pressure cylinder is proposed.It overcomes the limitation of the detection efficiency caused by the asynchronous temperature recovery of the two chambers in the asymmetric differential pressure method and uses the differential pressure substitution equation to replace the differential calculation of the differential pressure.The improved differential pressure method proposes an innovation based on the detection principle and calculation method.Additionally,the influence of the parameters in the differential pressure substitution equation on the leakage calculation results was simulated,and the specific physical significance of the parameters of the differential pressure substitution equation was explained.The experiments verified the fitting effect and proved the accuracy of this method.Compared with the traditional differential pressure method,the maximum leakage deviation of inhibition was 0.5 L/min.Therefore,this method can be used to detect leaks in air tanks.

Simulation and experimental study of high pressure switching expansion reduction considering real gas effect

Switching expansion reduction(SER)uses a switch valve instead of the throttle valve to realize electronically controlled pressure reduction for high pressure pneumatics.A comprehensive and interactive pneumatic simulation model according to the experimental setup of SER has been built.The mathematical model considers heat exchanges,source air pressure and temperature,environmental temperatures and heat transfer coefficients variations.In addition,the compensation for real gas effect is used in the model building.The comparison between experiments and simulations of SER indicates that,to compensate the real gas effect in high pressure discharging process,the thermal capacity of air supply container in simulation should be less than the actual value.The higher the pressure range,the greater the deviation.Simulated and experimental results are highly consistent within pressure reduction ratios ranging from 1.4 to 20 and output air mass flow rates ranging from 3.5 to 132 g/s,which verifies the high adaptability of SER and the validity of the mathematic model and the compensation method.

Flow characteristics and Shannon entropy analysis of dense-phase pneumatic conveying under high pressure

Experiments of dense-phase pneumatic conveying of pulverized coal using nitrogen are carded out in an experimental test facility with the conveying pressure up to 4. 0 MPa and the gas-solid ratio up to 450 kg/m^3. The influences of different conveying differential pressures, coal moisture contents, gas volume flow rates and superficial velocities on the solid-gas ratios are investigated. Shannon entropy analysis of pressure fluctuation time series is developed to reveal the flow characteristics. Through investigation of the distribution of the Shannon entropy under different conditions, the flow stability and the evolutional tendency of the Shannon entropy in different regimes and regime transition processes are discovered, and the relationship between the Shannon entropy and the flow regimes is also established. The results indicate that the solid-gas ratio and the Shannon entropy rise with the increase in conveying differential pressure. The solid-gas ratio and the Shannon entropy reveal preferable regularity with gas volume flow rates. The Shannon entropy is different for different flow regimes, and can be used to identify the flow regimes. Both mass flow rate and the Shannon entropy decrease with the increase in moisture contents. The Shannon entropy analysis is a feasible approach for researching the characteristics of flow regimes, flow stability and flow regime transitions in dense-phase pneumatic conveying under high pressure.

Generation of Arbitrary Pressure Pulsation of Wide Frequency Range for Flow Meter Testing in a Laminar Gas Pipeline

The present paper presents a device to test flow meters under an arbitrary pressure pulsation in a gas pipeline with a laminar flow containing frequency components up to 50 Hz, with the amplitude reaching hundreds of pascals. In order to reduce flow noise, the device has a strainer-like element connected to a pipeline under test and uses an open-loop control law based on the frequency response test. The control signal is calculated by adding the inputs to obtain each of the sinusoidal waves included in the original wave, which was decomposed by Fourier analysis. The validity of the developed method is demonstrated through the generation tests of superimposed pressure waves containing frequency components up to 50 Hz. Analysis of the relative uncertainty demonstrated the relative uncertainty to be less than 10% when the generated pressure is larger than 360 Pa.

Discharge Coefficient Measurements Using Heron's Fountain

Civil Engineering design students at CSUN (California State University, Northridge), aimed to demonstrate the pneumatic action of liquid water as it flows through an airtight one-way vessel system which is known as Heron’s Fountain. This project explores hydraulic and pneumatics principles commonly found in environment control systems, such as the non-isothermal heating facilities located on the CSUN campus. Since this was a simply constructed version of an ancient Greek fountain, its development required the collaboration of the team to execute its simple function. The parameters involved were diameter, length, height, and density. This analysis utilizes Pascal and Bernoulli’s equations to reinforce the principles of fluid mechanics. The fountain action is described based on flow rate and head loss is described by Darcy’s equation. Friction loss with an angled fitting attached to the fountain head is described by Reynold’s equation. The experiment observed the performances of two types of reentrant tube fittings for head loss: straight and angled. The experiment enhanced the educational experience of the research team by bringing together creative ideas from different educational and cultural backgrounds. The results of the experiment concluded with a 0.58% error for the straight fitting and 5.3% error for an angled fitting.

Current clinical approach to achalasia

Idiopathic achalasia is a rare primary motility disorder of the esophagus. The classical features are incomplete relaxation of a frequently hypertensive lower esophageal sphincter (LES) and a lack of peristalsis in the tubular esophagus. These motor abnormalities lead to dysphagia, stasis, regurgitation, weight loss, or secondary respiratory complications. Although major strides have been made in understanding the pathogenesis of this rare disorder, including a probable autoimmune mediated destruction of inhibitory neurons in response to an unknown insult in genetically susceptible individuals, a definite trigger has not been identified. The diagnosis of achalasia is suggested by clinical features and conf irmed by further diagnostic tests, such as esophagogastroduodenoscopy (EGD), manometry or barium swallow. These studies are not only used to exclude pseudoachalasia, but also might help to categorize the disease by severity or clinical subtype. Recent advances in diagnostic methods, including high resolution manometry (HRM), might allow prediction of treatment responses. The primary treatments for achieving long-term symptom relief are surgery and endoscopic methods. Although limited high-quality data exist, it appears that laparoscopic Heller myotomy with partial fundoplication is superior to endoscopic methods in achieving long-term relief of symptoms in the majority of patients. However, the current clinical approach to achalasia will depend not only on patients' characteristics and clinical subtypes of the disease, but also on local expertise and patient preferences.

A systematic review and meta-analysis of the Chinese literature for the treatment of achalasia

AIM: To evaluate the effect of different approaches in the treatment of achalasia in China. METHODS: We performed a systematic review and meta-analysis of Chinese literature by searching the Chinese Biomedical Database and Chinese scientific Journals database (up to March 2008). All cohort studies (controlled or uncontrolled) in which the patients were observed for more than a year were reviewed in detail. Dichotomous outcomes were reported as relative risks (RR) with 95% confidence interval (CI) for controlled trials. The efficacy in uncontrolled trials was assessed by a pooled estimate of response rate with individual studies weighted in proportion to the sample size. RESULTS: Seven controlled trials compared the effect of botulinum toxin injection (BoTx) with pneumatic dilation (PD). PD was superior to BoTx [65.2% vs 45.3%; RR 1.47 (95% CI 1.23-1.77), P < 0.0001], and had a lower clinical relapse rate (BoTx 30.2% vs PD 10%, RR 0.32 (0.16-0.65), P = 0.001). Heller myotomy (HM) had superior remission rate compared to PD [HM 94.0% vs PD 64.1%, RR 1.48 (1.15-1.99), P = 0.002]. In uncontrolled trials, the effectiveness of PD was 86.6% (23.9%) vs 94.8% (10.6%) for HM. The main complications of PD were perforation and gastroesophageal reflux disease. CONCLUSION: HM is the most effective long-term treatment for patients with achalasia in China. In the future, controlled clinical trials on the treatment of achalasia should focus on comparing laparoscopic myotomy with or without antireflux procedure,including different partial and total fundoplication techniques.

Current status in the treatment options for esophageal achalasia

Recent advances in the treatment of achalasia include the use of high-resolution manometry to predict the outcome of patients and the introduction of peroral endoscopic myotomy(POEM).The first multicenter randomized,controlled,2-year follow-up study conducted by the European Achalasia Trial group indicated that laparoscopic Heller myotomy(LHM)was not superior to pneumatic dilations(PD).Publications on the long-term success of laparoscopic surgery continue to emerge.In addition,laparoscopic single-site surgery is applicable to advanced laparoscopic operations such as LHM and anterior fundoplication.The optimal treatment option is an ongoing matter of debate.In this review,we provide an update of the current progress in the treatment of esophageal achalasia.Unless new conclusive data prove otherwise,LHM is considered the most durable treatment for achalasia at the expense of increased reflux-associated complications.However,PD is the first choice for non-surgical treatment and is more costeffective.Repeated PD according to an"on-demand"strategy based on symptom recurrence can achieve long-term remission.Decision making should be based on clinical evidence that identifies a subcategory of patients who would benefit from specific treatment options.POEM has shown promise but its long-term efficacy and safety need to be assessed further.

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. How- ever, 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 indepen- dent 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 sim- ulation 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.