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Mechanical Engineering. 2013;135(06):S2-S3. doi:10.1115/1.2013-JUN-4.
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This article discusses major technical goals and working fields of Center for Compact and Efficient Fluid Power (CCEFP). The CCEFP is an Engineering Research Center (ERC) supported by the National Science Foundation. The CCEFP, headquartered at the University of Minnesota, is a network of seven universities and over 50 companies and non-profit institutions. Research within the CCEFP is motivated and integrated in four major test bed systems: Mobile Heavy Equipment; Highway Vehicles; Mobile Human Scale Equipment; and Human Assist Devices. These test beds encompass current and future applications of fluid power, influence neighboring applications, and solve important societal problems. Recent research initiatives at CCEFP are also addressing new fluid power applications in the larger and smaller scale: wind power and medical micro-devices. Strategic reviews of each test bed identified the technical barriers that must be overcome to achieve success.

Commentary by Dr. Valentin Fuster
Mechanical Engineering. 2013;135(06):S4-S6. doi:10.1115/1.2013-JUN-5.
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This paper explores research into hydraulic hybrids that span a wide range of applications from heavy-duty vehicles, such as city buses, to small passenger vehicles. This case study also highlights the importance of having a well-designed energy management strategy if one is to maximize benefit of the hybrid powertrain. There is potential for hydraulic hybrid vehicles to offer a cost-effective solution to the need for increased efficiency in transportation systems. The high-power density of fluid power makes it a natural choice for energy storage in urban driving environments where there are frequent starts/stops and large acceleration/braking power demands. Because the opportunities and challenges of fluid power are different than those of electrical power, unique control strategies are needed and a summary of common energy management strategies (EMS) design methods for hydraulic hybrids has been presented.

Commentary by Dr. Valentin Fuster
Mechanical Engineering. 2013;135(06):S7-S9. doi:10.1115/1.2013-JUN-6.
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This article explores various functional aspects of hydraulic free piston engine (FPE) enabled by action motion control. Given the potential for high efficiency and flexibility, the FPE is well suited for mobile applications such as on-road vehicles and off-road heavy machinery. The advantage of the active motion controller lies in its ability to precisely track and shape the piston trajectory. FPE has a great potential for energy saving and emission control, but its reliable operation is limited by the complex dynamic coupling among the engine subsystems and the lack of the crankshaft. This inherent technical barrier for FPE could be overcome by active control with today’s sensing, actuation and computing technologies. A prototype hydraulic FPE is used to demonstrate the capabilities of active piston motion control. Experimental results demonstrate the feasibility and promise of the technology. Engine power control will be combined with piston motion control in the future to achieve a wider range of engine operation and higher engine efficiency.

Commentary by Dr. Valentin Fuster
Mechanical Engineering. 2013;135(06):S10-S12. doi:10.1115/1.2013-JUN-7.
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This article focuses on the use of a free-liquid-piston engine compressor (FPEC) for compact robot power. The FPEC presented in the article combines the engine and the compressor into a single unit. FPEC, a high-power density form of actuation, can help operate human-scale robots. An energy source that provides pneumatic power presents an appealing alternative that alleviates many of the scalability problems of hydraulics while preserving a high actuation power density. The system also presents additional advantages such as power-on-demand with no idle. Taking advantage of the high inertance piston, high-pressure air and high vapor pressure fuel enable the engine to operate in an inject and fire cycle. Dynamically, the FPEC is similar to a bug converter circuit in that the flow is amplified and the high-inheritance piston plays the same energetic role as the inductor. The data suggests that pneumatic systems using the FPEC as a power source would exhibit system energy densities comparable to, if not better than, the best electrochemical systems.

Commentary by Dr. Valentin Fuster
Mechanical Engineering. 2013;135(06):S13-S16. doi:10.1115/1.2013-JUN-8.
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This article introduces recent developments and challenges related to magnetic resonance imaging (MRI)-compatible medical devices. Recent advances in fluid-powered medical devices are described, including a needle steering robot for neurosurgery and a haptic device for hemiplegia rehabilitation. Recent three-dimensional printing technologies for fabricating integrated fluid-powered robots are also reported. The use of additive manufacturing conjoined with modern digital imaging techniques allow for the customization of components, a trait that is generally needed in medical implants and devices. Furthermore, the materials that are available in additive processes allow for direct end-use production of customized components and devices. In addition, the polymer-based materials have an inherently low permeability, allowing for use in an MRI environment while not causing imaging interference. Presently, selective laser sintering (SLS), stereolithography, and extrusion processes illustrate and suggest that they offer the greatest promise in MRI compatible end-use components. Future work is aimed at using Additive Manufacturing (AM) to develop inherently safe, compact, MRI compatible medical devices.

Commentary by Dr. Valentin Fuster
Mechanical Engineering. 2013;135(06):S17-S20. doi:10.1115/1.2013-JUN-9.
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This article introduces the concept of blending fluid power with mechanical structure through addictive manufacturing. Today, fluid-powered devices are manufactured using conventional fabrication practices. The additive process enables integrated structure, actuation, fluid passages, thermal management, and control within a single fabrication process. Fluid can be routed efficiently through the structure without the need for cross-drilled holes or plugs. Fluid passages can be optimized for heat dissipation and minimized head loss. One of the primary issues regarding parts manufactured using the additive manufacturing process is their mechanical properties. Results show that components made with Ti-6-4 powders have a minimum yield stress and ultimate strength that exceeds Grade 5 specifications. The Arcan system uses a powder bed that has an elevated temperature. Therefore, the part exhibits very little residual stress during the manufacturing process. This leads to improved mechanical strength but induces challenges in powder removal. The specific advantages are reduced weight, potential for lower cost, and reduced part counts.

Commentary by Dr. Valentin Fuster
Mechanical Engineering. 2013;135(06):S21-S22. doi:10.1115/1.2013-JUN-10.
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This article presents in depth the history activities of the Dynamic Systems and Control Division (DSCD) in the last 20 years. The 10 most cited papers from this 20-year period have been discussed in the article. Of these 10 papers, 4 of them are review or survey articles. The topics vary, showing the scope of DSCD’s activities: system identification, time delay systems, multivehicle control, and elastic manipulator arms. The most cited article is about nanotechnology; other areas represented are machine tool control, mechanical control to minimize vibrations, automotive, and piezoelectric actuators. These papers do stay true to the mechanical engineering roots of the DSCD. Other than the paper on time-delay systems, all of these papers directly reference mechanical systems. Some are application specific and others refer to specific classes of mechanical systems such as flexible manipulators.

Commentary by Dr. Valentin Fuster
Mechanical Engineering. 2013;135(06):32-35. doi:10.1115/1.2013-JUN-1.
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This article focuses on various research efforts that are being undertaken to address underwater noise. One of the U.S. National Oceanographic and Atmospheric Administration (NOAA)’s findings is that underwater sound has been doubling every 10 years. Most of this sound is man-made, from the ever expanding fleet of ships that ride our oceans. Researchers believe that intrusive sound is harming sea life. Many organizations around the US shipbuilding industry have seen the need to address underwater noise. Standards organizations such as International Organization for Standardization (ISO), American National Standards Institute (ANSI), and the Acoustical Society of America have been working overtime to develop standards for the measurement of underwater noise from ships, oil and gas exploration, pile driving, and other sources. The ship classification societies are adding underwater noise to their library of regulations. In the United States, the Society of Naval Architects and Marine Engineers are planning to add their own regulations or guidelines in the near future.

Commentary by Dr. Valentin Fuster
Mechanical Engineering. 2013;135(06):36-41. doi:10.1115/1.2013-JUN-2.
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This article highlights different research efforts to utilize thermal energy and thermal energy storage technologies. At several technical and panel sessions at the November ASME International Mechanical Engineering Congress and Exposition in Houston, there has been much discussion of cutting-edge work in thermal energy storage, including thermal energy storage materials, applications, and systems. Research into thermal energy storage is not limited to the confines of government and academia. Private companies are investigating whether they can incorporate thermal storage into some of their systems. Another potential advantage for solar thermal power is efficiency. Storing thermal energy as sensible heat is the most straightforward of the three methods, and the one that is the most widely deployed. A wide range of materials from simple concrete to synthetic oils has been tried for storing thermal energy. An energy storage system based on latent heat released as a material changes phase can be cost-effective. Thermal energy storage can become a game-changing technology wherever energy demand does not align exactly with energy supply. However, significant development challenges remain before these potential benefits can be realized.

Commentary by Dr. Valentin Fuster
Mechanical Engineering. 2013;135(06):42-47. doi:10.1115/1.2013-JUN-3.
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This article reviews the transformation and application of inspection and measurement (I&M) technology in the manufacturing industry. I&M offers a wealth of information needed in the development of new products. Cummins and Ford are among the pioneers in connecting I&M systems to the rest of their companies’ computerized decision support systems. Both companies are making wider use of I&M information and bringing factory floor and top-level decision-making closer together. Inspection, test, and measurement results are also vital to establishing the performance of the assembly tools and the capabilities of the processes. Lack of good I&M information can help weaken competitiveness and undermine strategies such as design for manufacturing and design for assembly. Timeliness is also crucial. Squirreling I&M data away in engineering silos perpetuates inspection and measurement as the last island of automation, the repository of information learned and lost.

Commentary by Dr. Valentin Fuster

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