Abstract:A new method is proposed to determine magnetic properties of the unsaturated-magnetized, small and irregular shaped rotor of a novel gyro. The method is based on finite-element analysis and the measurements of the magnetic flux density distribution, determining magnetic parameters by comparing the magnetic flux intensity distribution differences between the modeling results under different parameters and the measured ones. Experiment on a N30 Grade NdFeB magnet shows that its residual magnetic flux density is … Show more
“…Furthermore, it is relatively suitable for the liquid-suspended gyroscope. We magnetised the hollow disc-shaped rotor across the diameter, and alternating currents were imposed on the coils to produce rotating magnetic field that causes the rotor to rotate with high velocity [17]. Figure 1 Structure and principle of liquid-suspended rotor gyroscope: (a) structure and components, and (b) working principle of a levitated rotational gyroscope.…”
Section: Structure and Principle Of Liquid-suspended Rotor Gyroscopementioning
confidence: 99%
“…Furthermore, it is relatively suitable for the liquid-suspended gyroscope. We magnetised the hollow disc-shaped rotor across the diameter, and alternating currents were imposed on the coils to produce rotating magnetic field that causes the rotor to rotate with high velocity [17].…”
Surface tension and friction are dominant forces at microscale. The friction and wear of solidsolid or solid-liquid contacts affect the performance and lifetime of a microgyroscope. In this paper, we propose a novel superoleophobic liquid-bearing microgyroscope, and present a simple method to fabricate a superoleophobic surface on a 2J85 ferromagnetic alloy substrate through hydrofluoric acid etching. The superoleophobic surfaces exhibit reduced viscous drag because of the 'slip' associated with a layer of air trapped at the liquid/solid interface. In addition, a drag reduction ratio of approximately 10.7% was observed at a high velocity.
“…Furthermore, it is relatively suitable for the liquid-suspended gyroscope. We magnetised the hollow disc-shaped rotor across the diameter, and alternating currents were imposed on the coils to produce rotating magnetic field that causes the rotor to rotate with high velocity [17]. Figure 1 Structure and principle of liquid-suspended rotor gyroscope: (a) structure and components, and (b) working principle of a levitated rotational gyroscope.…”
Section: Structure and Principle Of Liquid-suspended Rotor Gyroscopementioning
confidence: 99%
“…Furthermore, it is relatively suitable for the liquid-suspended gyroscope. We magnetised the hollow disc-shaped rotor across the diameter, and alternating currents were imposed on the coils to produce rotating magnetic field that causes the rotor to rotate with high velocity [17].…”
Surface tension and friction are dominant forces at microscale. The friction and wear of solidsolid or solid-liquid contacts affect the performance and lifetime of a microgyroscope. In this paper, we propose a novel superoleophobic liquid-bearing microgyroscope, and present a simple method to fabricate a superoleophobic surface on a 2J85 ferromagnetic alloy substrate through hydrofluoric acid etching. The superoleophobic surfaces exhibit reduced viscous drag because of the 'slip' associated with a layer of air trapped at the liquid/solid interface. In addition, a drag reduction ratio of approximately 10.7% was observed at a high velocity.
“…Due to high hysteresis energy and mechanical strength, FeCrCo magnetic alloy is suitable for miniature devices. 2–5 Miniaturized micro-electromechanical systems (MEMS), micro-reactors, and micro-mechanical devices have applications in automobiles, aircrafts, telecommunication, mobiles, computers, laptop computers, home appliances, and medical devices. 6 High end applications in aviation, railway transport, and shipbuilding require magnetic materials that possess combination of good machinability as well as good mechanical and magnetic properties.…”
Fe-Cr-Co is a typical spinodal decomposition type magnetic alloy. FeCrCo alloys being highly workable are important for slender feature designs and ductile applications. However, due to the rising prices of cobalt, research is increasingly being focused toward reducing the amount of cobalt in FeCrCo semi-hard magnetic alloys, without compromising on their magnetic properties. Silicon is ferrite stabilizer and therefore, can be utilized as a potential alloying element. Few researchers have reported work on addition of silicon in FeCrCo alloys, especially on the double isothermal magnetic field annealing. In this work, FeCrCo alloy with 2% silicon addition was produced and subjected to different heat treatments. An electromagnetic setup equipped with a tube furnace was designed based on Finite Element Method (FEM) analysis, and developed for thermomagnetic treatments. An increase in remanence for double thermomagnetic treatment was noted. This improvement could be attributed to the transformation of retained α phase into α1 phase. It was also observed that the squareness of the M-H curve improved with the double treatment.
We proposed a miniaturized two-degrees of freedom (DOF) rotational gyro with a ball-joint supported permanent magnet rotor. The structural design and the dynamic model of the gyro are presented and analyzed in detail in this paper and testified by preliminary experiments. When the rotor tilts away from its null position, it will be constrained by a contactless magnetic equivalent elastic torque derived from the driving structure. As a rotational gyro, this structure is very simple and small, with a core size less than 6 cm3, and it needs only 0.75 W to keep the rotor spinning at a speed of 15 000 revolutions per minute (rpm) in a standard air pressure condition. Preliminary measurements show that, at 7000 rpm within a full scale of ±100 °/s, the gyro has a scale factor of 18.69 mV/(°/s), and a nonlinearity of 0.33% is also achieved through calculation. The results show that the gyro can be used to measure two DOFs' angular rates of carriers without close-loop control due to the existence of magnetic equivalent elasticity.
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