Pneumatic System Research Articles

Comparison of a two-step Tempus600 hub solution single-tube vs. container-based, one-step pneumatic transport system.

Efficient and timely transportation of clinical samples is pivotal to ensure accurate diagnoses and effective patient care. During the transportation process, preservation of sample integrity is crucial to avoid pre-analytical aberrations on laboratory results. Here, we present a comparative analysis between a two-step Tempus600 hub solution single-tube and a one-step, container-based pneumatic transport system (PTS) from Airco, for the in-house transportation of blood samples. Ten blood samples from healthy volunteers were split in 10 mL collection tubes filled at full or half capacity for transportation with the two PTS (about 250 m). To compare the impact of transportation, markers of hemolysis such as lactate dehydrogenase (LDH), potassium (K+), and the hemolysis index (HI), were determined. Additionally, differences in HI in routine samples and repeated transportation was investigated. To assess and compare the mechanistic impact profiles, we recorded the acceleration profiles of the two PTS using a shock data logger. Transportation using the Tempus600 hub solution resulted in 49 and 46 % higher HI with samples filled to total or half capacity, respectively. Routine samples transported with the Tempus600 hub solution showed a higher median HI by 23 and 33 %. Additionally, shock logger analysis showed an elevated amount of shocks (6.5 fold) and shock intensities (1.8 fold). The Tempus600 hub solution caused an increased number of unreportable LDH or K+ results based on the hemolysis index. However, it was only statistically significant for LDH (p<0.01 and p<0.08)- while the comparisons for K+ were not statistically significant (p<0.28 and p<0.56).

Model-based and model-free position control of a servo pneumatic system in the presence of uncertainties and disturbances

Trajectory tracking in electro-pneumatic systems poses a significant challenge due to the nonlinearity of their dynamics. This research aims to analyze the performance of various types of controllers for a laboratory-scale pneumatic system in terms of energy consumption and control efforts. By considering the mathematical relationships among system components, a precise gray-box mathematical model is developed based on experimental data. Subsequently, different linear model-free and nonlinear model-based controllers, is designed and their performances are compared by measuring tracking error, control effort, maximum overshoot, settling time, robustness against disturbances, and energy efficiency in the presence of severe disturbances. The effectiveness of these control methods is assessed through experimental tests and compared.

Aeolian Biodispersal of Terrestrial Microorganisms on Mars Through Saltation Bombardment of Spacecraft.

A major unknown in the field of planetary protection is the degree to which natural atmospheric processes remove terrestrial microorganisms from robotic and crewed spacecraft that could potentially contaminate Mars (i.e., forward contamination). We present experiments in which we measured the removal rate of Bacillus subtilis HA101 spores from aluminum surfaces under the bombardment of naturally rounded sand grains. To simulate grain impacts, we constructed a pneumatic sand-feed system and gun to accelerate grains to a desired speed, with independent control of impacting grain mass, flux, and angle. Spore counts of the resulting bombarded surfaces when using scanning electron microscopy indicate that although spores directly impacted by sand grains would likely be killed, those immediately adjacent to grain impacts might be released into the environment intact. The experiments demonstrate a linear relationship between the fractional dislodgement rate of spores and grain impact speed, which can be used to estimate input to microbial transport models (e.g., using numerical models of saltation). Even the slowest grain impacts (∼2.7 m/s) dislodged spores. Such slow events may be common and widespread on Mars, which suggests that microbial dislodgement by slow saltation near the surface is largely unavoidable.

Modelling and Transmission Characteristics Analysis of APU Pneumatic Servo System

The auxiliary power unit (APU), which is a compact gas turbine engine, is employed to provide a stable compressed air supply to the aircraft. This compressed air is introduced into the various aircraft components via the pneumatic servo system, thereby ensuring the normal operation of the aircraft’s systems. The objective of this study is to examine the impact of parameter variation on the transmission characteristics of an APU pneumatic servo system, with a particular focus on the aerodynamic moment associated with the operating process of a butterfly valve. To this end, a mathematical model of the pneumatic servo system has been developed. The accuracy of the mathematical model was verified by means of numerical simulation and comparative analysis of experiments. The simulation model was established in the Matlab/Simulink environment. Furthermore, the effects of throttling area ratio, fixed throttling hole diameter, rodless chamber volume of actuator cylinder and gas supply temperature on the transmission characteristics of the system were discussed in greater detail. The findings of the research indicate that the throttle area ratio is insufficiently sized, which results in a deterioration of the system’s linearity. Conversely, an excessively large throttle area ratio leads to a reduction in the controllable range of the load axis and is therefore detrimental to the servo mechanism of the flow control. An increase in the diameter of the fixed throttling hole or a decrease in the volume of the rodless cavity of the actuator cylinder facilitates a rapid change in flow rate within the rodless cavity and an increase in the response speed of the load-rotating shaft of the servomechanism. An increase in the temperature of the gas supply from 30 °C to 230 °C results in a reduction in the response time of the system by a mere 0.2 s, which has a negligible impact on the transmission characteristics of the system.

Bio-inspired circular soft actuators for simulating defecation process of human rectum.

Soft robots have found extensive applications in the medical field, particularly in rehabilitation exercises, assisted grasping, and artificial organs. Despite significant advancements in simulating various components of the digestive system, the rectum has been largely neglected due to societal stigma. This study seeks to address this gap by developing soft circular muscle actuators (CMAs) and rectum models to replicate the defecation process. Using soft materials, both the rectum and the actuators were fabricated to enable seamless integration and attachment. We designed, fabricated, and tested three types of CMAs and compared them to the simulated results. A pneumatic system was employed to control the actuators, and simulated stool was synthesized using sodium alginate and calcium chloride. Experimental results indicated that the third type of actuator exhibited superior performance in pressure generation, enabling the area contraction to reach a maximum value of 1. The successful simulation of the defecation process highlights the potential of these soft actuators in biomedical applications, providing a foundation for further research and development in the field of soft robotics.

A Pneumatic Soft Exoskeleton System Based on Segmented Composite Proprioceptive Bending Actuators for Hand Rehabilitation.

Soft pneumatic actuators/robotics have received significant interest in the medical and health fields, due to their intrinsic elasticity and simple control strategies for enabling desired interactions. However, current soft hand pneumatic exoskeletons often exhibit uniform deformation, mismatch the profile of the interacting objects, and seldom quantify the assistive effects during activities of daily life (ADL), such as extension angle and predicted joint stiffness. The lack of quantification poses challenges to the effective and sustainable advancement of rehabilitation technology. This paper introduces the design, modeling, and testing of pneumatic bioinspired segmented composite proprioceptive bending actuators (SCPBAs) for hand rehabilitation in ADL tasks. Inspired by human finger anatomy, the actuator's soft-joint-rigid-bone segmented structure provides a superior fit compared to continuous structures in traditional fiber-reinforced actuators (FRAs). A quasi-static model is established to predict the bending angles based on geometric parameters. Quantitative evaluations of predicted joint stiffness and extension angle utilizing proprioceptive bending are performed. Additionally, a soft under-actuated hand exoskeleton equipped with SCPBAs demonstrates their potential in ADL rehabilitation scenarios.

Critical Value Reporting Performance Improvement Initiative: A Journey Towards Timely Patient Safety

Abstract Timely reporting of critical values serves as a quality indicator for the National Patient Safety Goal. Since the oncology inpatient unit at our institution has the highest number of critical values and often struggles to meet the targeted goal of timely results acknowledgement, this prompted a performance improvement initiative. By utilizing the Institute for Healthcare Improvement (IHI) Model for Improvement, the study aimed to decrease the time from specimen collection to acknowledgment of a complete blood count critical values (overall TAT). Three key metrics were monitored, including unit turnaround time (time from collection to receipt in laboratory; uTAT), laboratory turnaround time (time from receipt in laboratory to verified results) and timely critical value acknowledgment rate (% acknowledgement within 30 minutes). Quality improvement tools such as process maps and fishbone diagrams were employed, and two areas for improvement were identified. Firstly, it was observed that samples collected by the phlebotomists were delivered in batch to the laboratory via carts. However, samples collected by nurses were sent to the laboratory via a pneumatic tube. Hence, the uTAT varied drastically due to the different delivery methods. Secondly, the mode of alerting providers regarding critical values, which was via telephone calls from telecommunication staff, was deemed disruptive and redundant, as the providers often were already aware of the results from the electronic medical record (EPIC). Two multi-cycle Plan-Do-Study-Act (PDSA) interventions were implemented by a multidisciplinary team. The first focused on sending samples via pneumatic tube. The second PDSA intervention focused on a direct clinician acknowledgment of critical values within EPIC, by creating an auxiliary column on the EPIC patient list. Consequently, the overall TAT decreased from a median time of 167 minutes in July 2021 to 140 minutes by March 2022 in the oncology inpatient unit, with a sustained result (139 minutes) by October 2023. This reduction was driven by the standardization of pneumatic tube delivery system; the uTAT decreased from a median time of 104 minutes to 46 minutes by March 2022 and remained low at 52 minutes by January 2024. Notably, the rate of timely acknowledgment of critical value results worsened, dropping from 67% to as low as 51 % (March 2022) and improved to 64% by January 2024. It was realized that this unintended consequence was attributed to the decrease in uTAT, leading to more critical value results reported in early morning when there was less staffing. Despite the worsening in timely critical value acknowledgment, the overall TAT showed a discernible reduction. The application of IHI methodology played a pivotal role in expediting result reporting. Subsequent steps will focus on utilizing secure communication channels to augment the success rate of critical values acknowledgment within 30 minutes.

Validating a Pneumatic Tube System for Blood Product Delivery

Abstract Introduction/Objective Timely delivery of blood products can be of utmost importance to providing quality care. We aimed to validate the use of a high-speed pneumatic tube system (PTS) that was already installed at our hospital. By reducing delivery times, patient resuscitation and survivability can be increased. Methods/Case Report We followed the Association for the Advancement of Blood &amp; Biotherapies (AABB) guidelines to validate a PTS in a large tertiary academic medical center. The requirements include: verifying product suitability, ensuring product integrity, temperature monitoring, transportation time measurements, and proper packaging and tracking of product receipt. We validated the transfer of packed red blood cells (PRBC), plasma, platelets, and cryoprecipitate from the central blood transfusion services lab (BTS) to nursing stations in a separate building up to 1500 feet (&amp;gt;1/4 mile) away using a Swisslog Translogic® PTS Inclusion with foam inside the PTS carriers helped reduce bumps during transit and insulated products from heat. Results (if a Case Study enter NA) The mean temperature of the PRBC was 6.6 degrees Celsius and none exceeded the AABB maximum of 10 degrees Celsius. The mean time for blood products transit to the nursing stations was 3 minutes (m) and 33 seconds (s). The median time was 3m 31s, and it ranged from 2m 18s to 5m 38s. The PTS reduced delivery times of blood products by up to 10-12 minutes compared to manual porters. Conclusion Transporting blood products via PTS is an efficient method that reduces the required manpower and leads to better utilization of resources. However, it is essential to validate the PTS system before implementing it operationally.

Directional soft jumper by harnessing asymmetric snapping of a semi-open shell

Precise control of the jumping direction and trajectory of soft robotics poses a challenge due to their large deformation and low stiffness. In this paper, we propose a pneumatic soft actuator consisting of an inward semi-spherical shell with a pre-existing T-shaped incision, which exhibits asymmetric snapping-through buckling under an increasing internal pressure. During the dynamic snapping, the shell deforms rapidly, resulting in an asymmetric, inclined impact with the ground. The impact force drives the soft actuator to jump in a controllable direction, and the adopted semi-open pneumatic system greatly improves the efficient utilization of air ejection energy. This design not only enhances the jumping performance, but also allows the control of the trajectory through adjusting the air pressure. Our experiments demonstrate that the actuator can achieve various jumping functions, for examples, to jump over obstacles of varying heights and depths, to execute rapid and continuous locomotion, and even to escape from a deep bottle. This work offers a paradigmatic idea for designing highly maneuverable and controllable soft robots.

Nuclear hyperpolarization in electron-transfer proteins: Revealing unexpected light-induced 15N signals with field-cycling magic-angle spinning NMR

The solid-state photo-CIDNP (photo-chemically induced dynamic nuclear polarization) effect allows for nuclear hyperpolarization, i.e., non-Boltzmann nuclear spin population. The effect relies on the light-induced formation of a spin-correlated radical pair (SCRP) and has been observed in various photosynthetic reaction center (RC) proteins and flavin-containing light, oxygen, voltage (LOV) proteins. Both systems exhibit strongly enhanced NMR signals originating from the electron transfer partners. Here, we present experimental data on the magnetic field dependence of the 15N solid-state photo-CIDNP effect in both phototropin LOV1 C57S from Chlamydomonas reinhardtii and the bacterial photosynthetic RC from Rhodobacter sphaeroides. Using a pneumatic field-cycling system, samples containing a frozen solution of the proteins are explored between 0.25 T and 9.4 T. Both systems yield hyperpolarized 15N NMR signals across the entire magnetic field range originating from the electron transfer moieties. Also, in both systems, hyperpolarized signals from unexpected positions are detected between 1.0 T and 2.0 T: position N-1 of the flavin in the LOV1 protein and the τ-N of the axial magnesium-coordinating histidine of the donor. A first attempt to explain the occurrence of these unexpected signals based on quantum chemical calculations is presented.

Precision polishing force control technology of abrasive belt-wheel polishing servo control system based on HGO-SMC

Due to cylinder friction, valve dead zone effect, flow nonlinearity, and measurement noise exist in pneumatic system. In the actual machining, it is difficult to achieve precise control of the pneumatic servo polishing system using the traditional PID algorithm, so the machining accuracy of the blades cannot be guaranteed. A sliding mode control (SMC) method based on high gain observer (HGO) is proposed. The HGO observes the output signal of the system and feeds the estimated signal back to the SMC to ensure that the observation error is uniform ultimate boundedness. Simulation and experiments show that compared with the PID algorithm, the steady-state error of HGO-SMC can be reduced by 66.4%. Compared with SMC(sgn), the high-frequency chattering of HGO-SMC can be reduced by 72.5%. Moreover, the polishing processing experiment shows that HGO-SMC can improve the form and position accuracy by 52.6% and reduce the surface roughness by 55.6%, compared with the original PID control algorithm of the polishing machine tool.

Conceptual Designing of a Pneumatic Warm-box System of Airship for Martian Exploration

Conceptual Designing of a Pneumatic Warm-box System of Airship for Martian Exploration

Innovative pressure control with ANFIS-enhanced mode switching for high-speed pneumatic systems

Abstract A pressure servo system, with compressed air as its primary power source, plays a pivotal role in automotive braking. The substitution of expensive proportional valves with high-speed switching valves (HSVs) for chamber pressure control remains a prominent challenge for researchers. In addressing the single-chamber dual-valve pressure tracking system, a novel approach is proposed using an Adaptive Neuro-Fuzzy Inference System (ANFIS) that enhances fuzzy control through neural network refinement. Integration with mode switching is employed to ameliorate chamber pressure tracking performance. This strategy amalgamates the learning capability of neural networks with the inferential capacity of fuzzy logic, effectively handling the intricate nonlinear characteristics of pneumatic systems. Experimental results demonstrate that for step signals in the range of 0.3 to 0.6 MPa, the maximum overshoot is reduced to 0.0041 MPa, and the random step error ranges between 0.01287~0.01275 MPa. The relative root mean square error for a 0.5 Hz harmonic signal is diminished by 26.91 %.

A Quantitative Assessment Approach to Implement Pneumatic Waste Collection System Using a New Expert Decision Matrix Related to UN SDGs

An innovative decision matrix has been developed to guide the selection and implementation of Pneumatic Urban Solid Waste Collection Systems (PUSWCS) in smart city projects. This study comprehensively collects and analyzes data on the advantages and disadvantages of pneumatic collection systems from technical, economic, and social perspectives. A decision-making tool was created to address the complexities of evaluating the desirability of incorporating PUSWCS in municipalities or specific areas, using a holistic approach. The tool assesses the technical, economic, and social feasibility of implementing PUSWCS, aligning it with the United Nations’ Sustainable Development Goals (SDGs). Specific variables are measured to assess compliance with the SDGs, distinguishing technical aspects from economic and social aspects. The methodology includes surveys of system users and technicians, expert assessments, and the development of a decision matrix that cross-references study variables and SDGs. The matrix assigns numerical values to the Magnitude (M) and Impact (I) of each variable, enabling quantitative interpretation. This holistic approach accommodates the complexities of waste management and diverse stakeholder perspectives. The results demonstrate the matrix’s effectiveness in accurately assessing the desirability of implementing PUSWCS. This confirms the matrix’s ability to optimally integrate with innovative smart city concepts and align with long-term sustainability goals. The study concludes that the design of the decision matrix allows the collection of information from experts, users, and stakeholders about economic, social, and environmental variables and relates them to the SDGs, to obtain a numerical result that allows to decide whether in a given urban environment it is advisable to implement a PUSWCS.

Pneumatic Piston Control Optimization

Abstract Piston control can be applied to regulate position, speed, acceleration, and force. The primary distinction between pneumatic and hydraulic cylinders lies in the working fluid: hydraulic systems utilize practically incompressible fluid, whereas pneumatic systems use compressible gas. Consequently, hydraulic cylinders offer more precise control over position and speed. In contrast, pneumatic cylinders are more influenced by external loads. However, pneumatic systems are simpler, more cost-effective than hydraulic systems, and more commonly used in laboratories, workshops, and production lines. They are typically employed for end-to-end motions [1] without requiring precise position control within the stroke. If a method to control pneumatic cylinders for intermediate positions within the stroke were developed, their application could be significantly expanded. In the paper titled “Pneumatic Piston Control Modelling and Optimization,” a method for controlling pneumatic pistons for industrial applications is presented [2]. Since then, the initial modelling has been further developed through practical experiments and fine-tuning. This paper summarizes the modelling efforts and introduces the experimental results.

Design and application of pneumatic rehabilitation glove system based on brain-computer interface.

Stroke has been the second leading cause of death and disability worldwide. With the innovation of therapeutic schedules, its death rate has decreased significantly but still guides chronic movement disorders. Due to the lack of independent activities and minimum exercise standards, the traditional rehabilitation means of occupational therapy and constraint-induced movement therapy pose challenges in stroke patients with severe impairments. Therefore, specific and effective rehabilitation methods seek innovation. To address the overlooked limitation, we design a pneumatic rehabilitation glove system. Specially, we developed a pneumatic glove, which utilizes ElectroEncephaloGram (EEG) acquisition to gain the EEG signals. A proposed EEGTran model is inserted into the system to distinguish the specific motor imagination behavior, thus, the glove can perform specific activities according to the patient's imagination, facilitating the patients with severe movement disorders and promoting the rehabilitation technology. The experimental results show that the proposed EEGTrans reached an accuracy of 87.3% and outperformed that of competitors. It demonstrates that our pneumatic rehabilitation glove system contributes to the rehabilitation training of stroke patients.

Enhanced energy conservation and response accuracy of a pneumatic control system

The energy consumption of pneumatic systems is occupying an increasingly considerable proportion in the industrial systems. However, due to the response characteristics of actuators, the pneumatic control system generally has a low energy utilization efficiency. How to improve the response accuracy of the pneumatic system while reducing energy consumption remains a key problem to be solved. In this paper, a three-voltage acceleration waveform and its generation method are proposed, and the acceleration circuit is designed. A multi-mode acceleration switching strategy and backstepping sliding mode controller (BSMC) are applied. The test results show that compared to the traditional methods, BSMC respectively saves 26.27% of the air consumption, as well as 32.35% of the valve group power consumption. It also achieves the lowest root-mean-square error (RMSE), of 4.8421kPa. All the experiments prove that the controller proposed can effectively improve the energy utilization efficiency while maintaining high tracking precision.

Dynamic control simulation of a new joint model with energy recovery during walking, using magnetorheological fluids, for lower limb prosthesis

AbstractResearchers can now utilize new materials to create innovative models for lower limb prostheses and explore novel ways to use them for efficient dynamic control. To achieve user-friendliness, one area of research focuses on recovering and reusing kinetic walking energy for dynamic control. This paper proposes a new design for a magnetorheological (MR) valve, along with a rotary actuator which offers a dynamic control for a lower limb prosthesis. The design will allow the storage of the energy during heel and mid-foot contact phases and to utilize it during toe support to lift the foot off the ground and establish a balance for the lower limb prosthesis. The energy is transferred through a magnetorheological hydraulic circuit and stored using a pneumatic system. The speed of energy transfer is regulated by magnetorheological valves. A series of MR valve designs were proposed and evaluated experimentally, which allowed the identification of the most suitable variant in the targeted application context. The design of the lower limb prosthesis was simulated using SolidWorks, and its dynamic behavior was analyzed in ANSYS.

An automated method for thrombocyte counting in capillary microsamples.

We aimed to develop an automated, low-volume method for thrombocyte counting in capillary blood using the Sysmex predilution (PD) mode. Microsamples were prepared by resuspension of 50 μL blood in 300 μL DCL CellPack. Thrombocyte counting was done in the impedance (PLT-I) and fluorescence (PLT-F) channels. The imprecision and bias was evaluated in >394 microsamples from adult blood. Preanalytical factors (skin-piercing, storage, and transportation in our pneumatic tube system) was assessed, and studies on pediatric microsamples were made for comparison. The improvement in analytical quality and turnaround time was examined. For PLT-F, the imprecision was 1.1%-3.7%, and the bias was 10.1% (95% CI: 8.8-11.3). After skin-piercing, the bias was 8.1% (95% CI: 5.6-10.6) and the imprecision 1.9% (95% CI: 1.3-2.5). Thrombocyte counts kept stable after 4 h at room temperature (94.8% [95% CI: 93.2-96.4]) and after pneumatic tube transportation [6.7% (95% CI: 4.8-8.6)]. The bias of the PD mode for pediatric microsamples was 13.0% (95% CI: -8.4-34.4) in the PLT-F channel. The automated method had a considerably lower imprecision than the existing manual thrombocyte counting method and reduced turnaround times. The automated microsample method offers a low-volume alternative for measurement of thrombocytes. The method appears useful also in pediatric samples.

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.