Performance of Magnetic-Superconductor Non-Contact Harmonic Drive for Cryogenic Space Applications

Harmonic drives are profusely used in aerospace mainly because of their compactness and large reduction ratio. However, their use in cryogenic environments is still a challenge. Lubrication and fatigue are non-trivial issues under these conditions. The objective of the Magnetic-Superconductor Cryogenic Non-contact Harmonic Drive (MAGDRIVE) project, funded by the EU Space FP7, is to design, build, and test a new concept of MAGDRIVE. Non-contact interactions among magnets, soft magnetic materials, and superconductors are efficiently used to provide a high reduction ratio gear that smoothly and naturally operates at cryogenic environments. The limiting elements of conventional harmonic drives (teeth, flexspline, and ball bearings) are substituted by contactless mechanical components (magnetic gear and superconducting magnetic bearings). The absence of contact between moving parts prevents wear, lubricants are no longer required, and the operational lifetime is greatly increased. This is the first mechanical reducer in mechanical engineering history without any contact between moving parts. In this paper, the test results of a −1:20 inverse reduction ratio MAGDRIVE prototype are reported. In these tests, successful operation at 40 K and 10−3 Pa was demonstrated for more than 1.5 million input cycles. A maximum torque of 3 N·m and an efficiency of 80% were demonstrated. The maximum tested input speed was 3000 rpm, six times the previous existing record for harmonic drives at cryogenic temperature

Aeronautical Magnetic Torque Limiter for Passive Protection against Overloads

Actual aerospace and defense technologies present multiple limitations that need to be overcome in order to evolve to less contaminating and more efficient aircraft solutions. Contactless technologies come with essential advantages such as the absence of wear and friction. This work describes the design, prototype, and performance test according to RTCA-DO-160 of an aeronautical magnetic torque limiter. The results show correct continuous transmission operation (2250 rpm and 24 Nm) from −50 °C to +90 °C. Moreover, overload protection has been demonstrated for more than 200 jamming events without damage or required maintenance to the device

Z-Damper: A New Paradigm for Attenuation of Vibrations

Magnetic linear gear provides a new and unique opportunity for coupling mechanical impedances and optimizing vibration damping. In the present paper a new magneto-mechanical vibration damper (the so-called Z-damper) is described. Its expected theoretical dynamic behavior shows a particularly high damping capability, a low frequency, as well as an optimal behavior for high frequencies

Approaches to Health Efficiency across the European Space through the Lens of the Health Budget Effort

In the context of the COVID-19 pandemic, financial resources allocated to the health system have been refocused according to priority 0: fighting the pandemic. The main objective of this research is to identify the vulnerabilities affecting the health budget effort in the EU and in the Member States during the health crisis period. The analysis takes into account relevant statistical indicators both in terms of financial allocation to health and expenditure on health protection of the population in the Member States, with the effect being tracked even during the pandemic period. The novelty of the study is the identification of viable directions of intervention based on the structural determination of expenditures related to measures to combat the pandemic and making proposals for changes in public policies based on the determination of the effectiveness of budget allocations in health in relation to the proposed purpose. The main outcome of the study is the identification of the vulnerabilities and the projection of measures to mitigate them in the medium and long term

Analysis of Corporate Entrepreneurship in Public R&D Institutions

This paper aimed at establishing a Corporate Entrepreneurship diagnosis model within public R&D institutions. We based our analysis on empirical identification of a generalized set of organizational factors, perceived as intrapreneurship vectors. The quantitative research targeted 50 experienced public entities and was based on validating one of the most popular psychometric instruments in the entrepreneurial literature: the Corporate Entrepreneurship Assessment Instrument (CEAI)—originally intended for the North American economic environment. As recent literature questioned the cross-cultural portability of psychometric instruments, this study intended to validate the five-factor intrinsic structure of CEAI. The five factors deduced by our statistical analysis were: support for opportunity investigations and reinforcement; dynamic environment and recognition; decreased formalization; knowledge sharing; time availability and strategic awareness. Next, the factor scores were used as input variables for a logistic regression procedure, with the output variable being the intrapreneurial value of the respondents’ institutions. Two factors contribute considerably to the predicted intrapreneurial value: support for opportunity investigations and reinforcement and decreased formalization. The validity of the whole approach is supported by the relevance of the original CEAI questionnaire, able to reveal intrapreneurial characteristics, and by the prediction power of the logistic regression model over the intrapreneurial propensity of public institutions

Aeronautical Magnetic Torque Limiter for Passive Protection against Overloads

Actual aerospace and defense technologies present multiple limitations that need to be overcome in order to evolve to less contaminating and more efficient aircraft solutions. Contactless technologies come with essential advantages such as the absence of wear and friction. This work describes the design, prototype, and performance test according to RTCA-DO-160 of an aeronautical magnetic torque limiter. The results show correct continuous transmission operation (2250 rpm and 24 Nm) from −50 °C to +90 °C. Moreover, overload protection has been demonstrated for more than 200 jamming events without damage or required maintenance to the device

Mechanical Impedance Matching Using a Magnetic Linear Gear

As part of the Fp7 Clean Sky Project, a linear magnetic gear prototype, called Z-transmitter, for aerospace application was designed, built, and tested. It demonstrates a maximum force capacity of 4700 N at 25°C and 4500 N at 90°C. Force ratio between slow and fast stages remains constant and equal to the design value: 7.0. The behavior of the real Z-transmitter as a mechanical impedance matching device when any stiffness is attached to the fast stage including the limit cases of a blocked fast stage or a free to move fast stage is experimentally explored. Although the real Z-transmitter deviates from the ideal, frictionless and massless, device, it still provides an impedance matching effect large enough to potentially become an extremely useful technology for vibration control when combined with other elements such as dampers, springs, or active elements

Mechanical Impedance Matching Using a Magnetic Linear Gear

As part of the Fp7 Clean Sky Project, a linear magnetic gear prototype, called Z-transmitter, for aerospace application was designed, built, and tested. It demonstrates a maximum force capacity of 4700 N at 25°C and 4500 N at 90°C. Force ratio between slow and fast stages remains constant and equal to the design value: 7.0. The behavior of the real Z-transmitter as a mechanical impedance matching device when any stiffness is attached to the fast stage including the limit cases of a blocked fast stage or a free to move fast stage is experimentally explored. Although the real Z-transmitter deviates from the ideal, frictionless and massless, device, it still provides an impedance matching effect large enough to potentially become an extremely useful technology for vibration control when combined with other elements such as dampers, springs, or active elements

Contactless Mechanical Components: Gears, Torque Limiters and Bearings

Contactless mechanical components are mechanical sets for conversion of torque/speed, whose gears and moving parts do not touch each other, but rather they provide movement with magnets and magnetic materials that exert force from a certain distance. Magneto-mechanical transmission devices have several advantages over conventional mechanisms: no friction between rotatory elements (no power losses or heat generation by friction so increase of efficiency), no lubrication is needed (oil-free mechanisms and no lubrication auxiliary systems), reduced maintenance (no lubricant so no need of oil replacements), wider operational temperature ranges (no lubricant evaporation or freezing), overload protection (if overload occurs magnet simply slides but no teeth brake), through-wall connection (decoupling of thermal and electrical paths and environmental isolation), larger operative speeds (more efficient operative conditions), ultralow noise and vibrations (no contact no noise generation). All these advantages permit us to foresee in the long term several common industrial applications in which including contactless technology would mean a significant breakthrough for their performance. In this work, we present three configurations of contactless mechanical passive components: magnetic gears, magnetic torque limiters and superconducting magnetic bearings. We summarize the main characteristic and range of applications for each type; we show experimental results of the most recent developments showing their performance