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Nowadays, due to advantages of maneuverability, portability and low cost, the mini quadrotor unmanned aerial vehicle (UAV) catches much attention. In some special applications such as narrow space search, stealth detection and cooperative detection in huge region, the mini quadrotor UAV is more suitable than a big one. However, light weight and mini size lead to phenomenon that it is hard for mini...
Rotary steerable system (RSS) is a new technique of drilling technology adopted in directional drilling. Compared with conventional directional drilling, RSS has the ability to improve the drilling efficiency, reduce the drilling risk and decrease the drilling cost at the same time. This paper summaries the fundamental structure, classification, directional principle and development process of RSS;...
A novel eddy current damper with hybrid excitation is presented in this paper. The eddy current damper contains two hybrid excitation components and a moving conductor plate. The hybrid excitation component is consisted of primary coil, the primary iron core and permanent magnet. The conductor plate is sandwiched between two excitation components. Analyses of the proposed damper are conducted with...
This paper introduces three-type voice coil motors (VCMs) for nano-positioning system. These VCMs all consists dual-magnet stator and coil mover which is sandwiched between these two-layer magnets with different topology structures of the stators and movers. The motor structures, magnetic field distribution, thrust force and force ripple of these VCMs are studied and compared. Equivalent magnetic...
This paper proposes a nano-positioning system driven by a high force density voice coil motor (VCM) and supported by a complex parallel four-bar flexure mechanism. The VCM employs bilateral Halbach permanent magnet (PM) arrays and triple-segment coils to achieve high force-current ratio and low force ripple. Complex parallel four-bar flexure mechanism is designed to obtain high stiffness and good...
This paper proposes a concept of free piston linear generator (FPLG) range-extender for the application of hybrid electric vehicles (HEVs). The coupling thermodynamics model of the FPLG range-extender is developed mathematically. Its stable operation characteristics are analyzed accordingly. In addition, the effects of the variations of the key operational parameters on the effective output power...
This paper proposes a novel moving-coil voice coil motor(VCM) used for driving nano-positioning device. This VCM implements bilateral Halbach array permanent magnet as the stator and three separated coils with the slotted coil skeleton as the mover. The VCM can achieve large stroke and nano-level positioning accuracy with the support of the compliant mechanism. Equivalent magnetic circuit method and...
This paper studies the dynamic response of a highspeed ball-screw drive in a machine tool feed system. The Timoshenko beam theory is employed to model the rotating screw, while the nut is modeled as a lumped moving mass subjected to an external force resolved into three mutually perpendicular components. The dynamic model of the ball-screw drive is formulated based on the assumed mode method. To study...
The free piston energy converter (FPEC) is a new type of power unit for hybrid electric vehicle. In a FPEC, an internal combustion engine driven permanent magnet linear generator (PMLG) may be utilized to produce electrical energy. This paper discusses the issues that are pertinent to the design of a linear permanent magnet generator for application in a FPEC. To achieve the required high power density...
A compact flywheel energy storage system assisted by axial-flux partially-self-bearing permanent magnet motor has been proposed by the authors. The proposed machine combines axial magnetic bearing and motoring functionality into a single magnetic actuator, which not only spins the rotor-flywheel but also generates a levitation force to overcome the gravity. The mathematical model of the levitation...
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