Air Motor Research Articles

G0700-2-2 回生機構付エアモータの性能測定(エンジンシステム部門一般講演(2))

G0700-2-2 回生機構付エアモータの性能測定(エンジンシステム部門一般講演(2))

Dynamic analysis and fuzzy logic control for the vane-type air motor

Air motors are widely used in the automation industry with special requirements, such as park-prohibited environments, mining, chemical manufacturing, and so on. However, during the past only few literatures discussed the dynamics of air motors or their control strategies. The purpose of this paper is to analyze the dynamics of a vane-type air motor, and design a fuzzy logic controller. It is found that the rotational speed of the air motor is strongly affected by the pressure and flow rate of the compressed air. Further, due to the mechanical friction, the overall system is actually nonlinear with dead-zone and has hysteretic behavior. The performance of conventional PI controllers implemented on the air motor usually results in large overshoot, slow response and significant fluctuation errors. To cope with the nonlinear effects of dead-zone and hysteretic behavior, we developed a fuzzy logic controller to improve the performance. The experimental results show that the proposed controller can effectively control the system with a settling time within 0.2 second, the error fluctuation less than 0.5% for high speed operation and 1.5% for low speed operation, and without any overshoot.

A robust sliding mode controller design for a ball screw table driven by an air motor

Air motors are often applied in the automation industry in areas with special requirements, such as in spark-prohibited environments, the mining industry, chemical manufacturing plants, and similar locations. The purpose of this study is to analyze the behaviors of a ball screw table powered by a vane-type air motor and to design a robust sliding mode controller for the inlet pressure. The rotational speed of the air motor is closely related to the pressure and flow rate of the compressed air. Furthermore, the compressibility of the air and the friction in the mechanism mean that the overall system is nonlinear, with fluctuating input. A robust sliding mode control is developed to overcome the effects of variations in the inlet pressure and air leakage problems. The experimental results validate the robustness of the proposed position control strategy.

Results of Multi-system Energy Savings Assessments (ESA) for a Chemical Processing Facility

ABSTRACT Multi-system energy savings assessments (ESAs) were completed in the fall of 2007 at a large chemical processing facility in Georgia. The plant manufactures food additives. The assessments were funded by combined contributions from the company and a grant from the state energy office. Energy systems assessed included steam, compressed air, chilled water, and electric motor drives. DOE Best Practice Tools were used to prepare the assessments. For the three energy systems studied, a total of 21 energy savings opportunities with a projected cost savings potential of $2.6 million were identified. These resulting cost savings distributed between the systems were: 44.3 percent boiler/steam, 35.5 percent compressed air, and 20.2 percent chilled water. Opportunities identified were representative ones, and additional opportunities are certainly possible with continued study and use of the DOE tools introduced. The estimated payback of the combined measures was less than one year. The process followed to ...

Audible acoustics in high-shear wet granulation: Application of frequency filtering

Previous work has shown analysis of audible acoustic emissions from high-shear wet granulation has potential as a technique for end-point detection. In this research, audible acoustic emissions (AEs) from three different formulations were studied to further develop this technique as a process analytical technology. Condenser microphones were attached to three different locations on a PMA-10 high-shear granulator (air exhaust, bowl and motor) to target different sound sources. Size, flowability and tablet break load data was collected to support formulator end-point ranges and interpretation of AE analysis. Each formulation had a unique total power spectral density (PSD) profile that was sensitive to granule formation and end-point. Analyzing total PSD in 10 Hz segments identified profiles with reduced run variability and distinct maxima and minima suitable for routine granulation monitoring and end-point control. A partial least squares discriminant analysis method was developed to automate selection of key 10 Hz frequency groups using variable importance to projection. The results support use of frequency refinement as a way forward in the development of acoustic emission analysis for granulation monitoring and end-point control.

Evidence of aerosolised floating blood mist during oral surgery

Dental surgery performed with high speed instruments, such as a dental turbine, air motor, or micro-engine handpiece, produces a large amount of splattering and particles, which can be contaminated by micro-organisms from the oral cavity. It has been speculated that such particulate mists contain blood-based elements. In the present study, we investigated whether blood-contaminated aerosol was present in a room where oral surgery was performed with high speed instruments. An extra-oral evacuator system was used for sample collection (N=132). For the experiment, a non-woven towel was set on the nozzle of the evacuator as a filter and invisible mist was collected at distances of 20, 60 and 100 cm from the surgical site. A leucomalachite green presumptive test was performed with each filter after every tooth extraction. At locations 20 and 100 cm from the surgical site, 76% and 57%, respectively, of the particulates were positive in blood presumptive tests. Based on our results, we consider that blood-contaminated materials have the potential to be suspended in air as blood-contaminated aerosol. These results indicate the risk of cross-infection at the dental practice for immunocompromised patients as well as healthy personnel.

Coating method and atomizer

A rotary atomizer (1) has a rotary atomizing head (4) driven by an air motor (2) at a rotational speed of 4,000˜5,000 rpm, for example. A coating material is supplied to a central portion of the rotary atomizing head (4) through a paint supply pipe (5). The atomizer (1) further includes a supersonic horn (6) having a vibration plane (6 a) located adjacent to the outer circumferential perimeter of the rotary atomizing head (4). The vibration plane (6 a) is an inclined plane gradually increasing its diameter forward. The coating material immediately after spattered from the outer circumferential perimeter of the rotary atomizing head (4) is exposed to supersonic vibration from the vibration plane (6 a), and it is atomized by the supersonic vibration to particles of a uniform grain size. At the same time, the atomized coating material is driven forward.

408 回生機構付エアモータ搭載車両の開発(応用熱工学III)

408 回生機構付エアモータ搭載車両の開発(応用熱工学III)

Force and energetic characteristics of a spiral air motor

It is examined whether it is possible to use a spiral volumetric device as an air motor. A mathematical model of a spiral air motor making it possible to calculate its power, torque, and energetic performance is obtained. It is shown that the spiral air motor has better specific characteristics than other types of rotary driving air motors.

Design and implementation of an air-powered motorcycles

Currently in Taiwan, there are more than 13 million motorcycles, mostly driven by internal combustion engines, and the pollutants, carbon monoxide (CO) and unburnt hydrocarbons (HC), generated by motorcycle are responsible for more than 10% of the air pollutants released to the atmosphere. The studies show that the internal combustion engines of motorcycles may generate up to two times more pollutants than those of automobiles. In order to improve the air pollution condition and eliminate the pollutants exhausting, this paper presents a new idea of using compressed air as the power sources for motorcycles. Instead of an internal combustion engine, this motorcycle is equipped with an air motor, which transforms the energy of the compressed air into mechanical motion energy. A prototype is built with a fuzzy logic speed controller and tested on the real road. The experiment data shows that the speed error is within 1 km/h and the efficiency is above 70% for this system when the speed is over 20 km/h.

Potential benefits from improved energy efficiency of key electrical products: The case of India

The economy of the world's second most populous country continues to grow rapidly, bringing prosperity to a growing middle class while further straining an energy infrastructure already stretched beyond capacity. At the same time, efficiency policy initiatives have gained a foothold in India, and promise to grow in number over the coming years. This paper considers the maximum cost-effective potential of efficiency improvement for key energy-consuming products in the Indian context. The products considered are: household refrigerators, window air conditioners, motors and distribution transformers. Together, these products account for about 27% of delivered electricity consumption in India. The analysis estimates the minimum Life-Cycle Cost option for each product class, according to use patterns and prevailing customer marginal rates in each sector. This option represents an efficiency improvement ranging between 12% and 60%, depending on product class. If this level of efficiency was achieved starting in 2010, we estimate that total electricity consumption in India could be reduced by 4.7% by 2020, saving over 74 million tons of oil equivalent and over 246 million tons of carbon dioxide emissions. Net present financial savings of this efficiency improvement totals 8.1 billion dollars.

A 3-DOF MR-Compatible Device for Magic Angle Related In Vivo Experiments

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The “magic angle” effect consists of the increase in signal intensity observed at a tendon or cartilage in a magnetic resonance image, when the tissue is oriented at an angle of approximately 55 <formula formulatype="inline"> <tex>$^\circ$</tex></formula> with respect to the main magnetic field <formula formulatype="inline"><tex>$B_{0}$</tex></formula>. The exploitation of this phenomenon is often used to assist diagnosis of tendinous and other diseases, although practical difficulties derived from positioning target tissue at the desired orientation inside closed-bore scanners has made this exploitation hard to implement. A 3-DOF MR-compatible mechatronic system has been developed to position a variety of limbs at the magic angle inside a closed-bore scanner, actuated by a custom-developed pneumatic air motor. The system is capable of locating the desired anatomy with high accuracy, and is designed to position the target tissue at a minimal distance from the isocenter. The compatibility of the system is demonstrated, producing negligible artifacts and an insignificant reduction in signal to noise of the image. Preliminary clinical trials scanning the Achilles tendon of healthy volunteers prove the functionality of the device. An increase in signal intensity of up to 21-fold has been recorded in the tendon at the magic angle. </para>

Fuzzy MRAC controller design for vane-type air motor systems

Air motors are widely used in the automation industry due to special requirements, such as spark-prohibited environments, the mining industry, chemical manufacturing plants, and so on. The purpose of this paper is to analyze the behavior of a vane-type air motor and to design a model reference adaptive control (MRAC) with a fuzzy friction compensation controller. It has been noted that the rotational speed of the air motor is closely related to the compressed air’s pressure and flow rate, and due to the compressibility of air and the friction in the mechanism, the overall system is actually nonlinear with dead-zone behavior. The performance of the previous controllers implemented on an air motor system demonstrated a large overshoot, slow response and significant fluctuation errors around the setting points. It is important to eliminate the dead-zone to improve the control performance. By considering the effects of the dead-zone behavior, we have developed an MRAC with fuzzy friction compensation controller to overcome the effect of the dead-zone. The following experimental results are given to validate the proposed speed control strategy.

A Compact Aerostatic Spindle Integrated with an Axial Positioning Actuator for Micro and Ultra-Precision Machine Tools

An aerostatic spindle integrated with an axial positioning actuator and an air motor has been proposed and fabricated for use in a compact high-precision milling machine. The main shaft of the spindle itself can be axially positioned using a built-in voice coil motor and rotated using an air motor so that the compact spindle system can realize both functions of a one-DOF positioning table and the spindle. The prototype main shaft, which is 20 mm in diameter, 147.5 mm in length and 0.26 kg in weight, could rotate at over 15,000 rpm. The main shaft can also be positioned using a laser interferometer system with an axial positioning range of..5 mm, and axial resolutions of 1.24 nm at rest and 24.7 nm at a speed of 15,000 rpm. Furthermore, the disturbance observer using the axial displacement and the current in the voice coil motor could react to an axial step force of 2 mN.

Genetic Algorithm-based Modeling and Optimization of Control Parameters of an Air Motor

Challenging optimization problems, which elude acceptable solutions via conventional methods, arise regularly in control systems engineering. Genetic algorithms are applied here to optimize the control gains for a controller of a pneumatic drive. We show that, by using minimum information specific to the system, near optimal values of the control gains can be obtained within 10 generations. Two main motivating factors are behind this kind of study; namely, the response of pneumatic drives is very slow, which leads to its inability to attain set points due to high hysteresis. Moreover, the dynamic model of the system is highly nonlinear, which greatly complicates controller design and development. To address these problem areas, two streams of research efforts have evolved—using conventional methods and adopting a strategy that does not require a mathematical model of the system

AN APPROACH TO ENERGY CONSERVATION FOR AIR MOTOR

There are many methods to improve actuator efficiency in pneumatic systems. In this research, the authors remodeled rotary valve of radial piston type air motor. During forward rotation, increasing Cut-off ratio of rotary valve which controls supply and exhaust timing can increase expansion process in this motor. As a result, air consumption was reduced, torque was increased and efficiency that we define as the ratio of air consumption to torque was improved. And the authors clarified the existence of an optimum angle in Cut-off ratio.Considering practical utilizations, performance of this motor is demanded for the same forward rotation as backward rotation. But actually, increasing Cut-off ratio increases compression process andderives efficiency worse.So the authors have proposed to remodel the casing of this motor in addition to increasing Cut-off ratio. This remodeling makes this motor the same performance forward rotation as backward rotation, but clearance volume expands. So the rate of increasing efficiency under this condition is less than under only remodeling Cut-off ratio. But we directed to possibility of improving efficiency.

Investigation of Damping Coefficient of Air Motor Rotation Experiment

The subject of this paper is the estimation of damping coefficients for an air motor rotation experiment. This paper studies three methods for the calculation of damping coefficients under the air motor rotation experiment, including the proposed inverse model, finite difference model and the application of Laplace transform method to deduce an equation for calculation of damping coefficient. In the air motor rotation experiment, the data of experimental angular velocity and experimental torque can be employed to calculate the damping coefficients by using the inverse model proposed by this paper. The advantage of the inverse model is that the damping coefficients, the angular velocity and the angular displacement for air motor rotation experiment can be obtained at the same time. But the finite difference method and the Laplace transform method can not do that. Synthesizing the analytic results, the inverse model proposed by this paper can reasonably calculate the damping coefficients for air motor rotation experiment.

Ports in a Storm

In many parts of the world, shipping-related emissions have already exceeded or are expected to soon exceed those from land-based sources. Shipping emissions can be reduced substantially by using some of the same technologies being applied to land-based sources, including cleaner engines and fuels, exhaust control methods, and operational modifications. Various ports are testing the feasibility of these mechanisms with varying degrees of success. What is perhaps most greatly needed is expedited creation of better regulations at all levels, from the International Maritime Organization to port city authorities.

Hybrid Energy Storage System Based on Compressed Air and Super-Capacitors with Maximum Efficiency Point Tracking (MEPT)

This paper presents a hybrid energy storage system mainly based on Compressed Air, where the storage and withdrawal of energy are done within maximum efficiency conditions. As these maximum efficiency conditions impose the level of converted power, an intermittent time-modulated operation mode is applied to the thermodynamic converter to obtain a variable converted power. A smoothly variable output power is achieved with the help of a supercapacitive auxiliary storage device used as a filter. The paper describes the concept of the system, the power-electronic interfaces and especially the Maximum Efficiency Point Tracking (MEPT) algorithm and the strategy used to vary the output power. In addition, the paper introduces more efficient hybrid storage systems where the volumetric air machine is replaced by an oil-hydraulics and pneumatics converter, used under isothermal conditions. Practical results are also presented, recorded from a low-power air motor coupled to a small DC generator, as well as from a first prototype of the hydro-pneumatic system. Some economical considerations are also made, through a comparative cost evaluation of the presented hydro-pneumatic systems and a lead acid batteries system, in the context of a stand alone photovoltaic home application. This evaluation confirms the cost effectiveness of the presented hybrid storage systems.

Determining the principal parameters of piston expansion engines by different computational methods

We consider various engineering methods of calculating the parameters of machines. We carried out experimental tests on laboratory specimens of the stages of a gas expansion engine and a compressed air motor (PEE). Relations are given here for determining the indicated power of a PEE with combined and countercurrent gas distribution systems as well as the main propositions of the procedure for engineering calculations.