• The KSFM Journal of Fluid Machinery
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• v.9 no.6 s.39
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• pp.54-62
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• 2006

An experiment about performance characteristics is conducted on a double chamber vane-type rotor. Three different rotors, which have 6, 8 and 9 vanes, are applied to the driver and various lift holes at the rear plate are used to increase the effective vane height. The inner diameter of a double chamber cylinder is ${\phi}27mm$, and the length of the cylinder is 65 mm. The maximum offset length between the rotor outer surface and the cylinder inner surface is 4.5 mm. In this study, specific output torques and powers are measured, and also noise and vibration are measured at the real operating situation. The operating torque on the double chamber is increased to 17% compared to the operating torque obtained at the single chamber which has the same size. The experimental results of noise and vibration show that the operating sound and vibration are directly related to the operating power generated by the double chamber rotor.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.1003-1011
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• 2012

A new type of gerotor developed in this paper has the inner rotor designed by inserting a polycircular-arc between the hypocycloid and epicycloid curves, and we also suggest that the outer rotor be designed using the closed-form equation for the inner rotor and a method of modification. Thus, it is possible to design a gerotor for which there is no cusp and loop, as in this case undercut is prevented. We developed automated program for rotor design and calculation of the flow rate and flow rate irregularity. And we also demonstrate the superior performance of the gerotor developed in this study by analyzing the internal fluid flow using a commercial computation fluid dynamics-code (CFD).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.12
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• pp.1535-1540
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• 2013

We propose a finite element modeling method considering the ball bearing contact mechanism, and the developed method was verified through experimental and analytical results of inner and outer race-type rotor systems. A comparison of the proposed method with conventional method reveals that there is little difference in the results of the inner race-type rotor system, but there are considerable differences in the results of the outer race-type rotor system such that predictions of greater accuracy can be made. Therefore, the proposed method can be used for accurately predicting the dynamic characteristics of an outer race-type rotary machine.

• Journal of Drive and Control
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• v.11 no.4
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• pp.15-24
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• 2014

It is difficult to analytically derive a volumetric displacement formula for a gerotor hydraulic motor due to the complexity of the geometric shape of its gear lobes. This work proposes an analytical method for the volumetric displacement, a relatively easy method based upon two physical concepts: conservation between hydraulic energy and mechanical shaft energy, and torque equilibrium for the rotor's motion. The first research using these concepts was conducted on inner and outer rotors rotating with respect to each rotor axis. This work represents the second report conducted on an inner rotor revolving as a planetary motion on the stationary outer rotor. The formula equations regarding the volumetric displacement and flow rate are derived, and the proposed formula about the volumetric displacement is proven to be the same as another analytical displacement formula: the so-called vane length method. From the formula, volumetric displacement is calculated for an example geometry of the gear lobes. The resultant displacement is confirmed to be the same as the value calculated from the chamber volume method. The proposed analytical formula can be utilized in the analysis and design of gerotor hydraulic motors. Because it is based on torque equilibrium, this formula can provide a better understanding of torque performance, such as torque ripple, in designing a gerotor type motor.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.57-62
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• 2004

This paper deals with a waypoint trajectory following problem for the tilt-rotor UAV under development in Korea (TR-KUAV). In this problem, dynamic model inversion based on the linearized model and Sigma-Phi neural network with adaptive weight update are involved to realize the waypoint following algorithm for the vehicle in the helicopter flight mode (nacelle angle=0 deg). This algorithms consists of two main parts: outer-loop system as a command generator and inner-loop system as stabilizing controller. In this waypoint following problem, the position information in the inertial axis is given to the outer-loop system. From this information, Attitude Command/Attitude Hold logic in the longitudinal channel and Rate Command/Attitude Hold logic in the lateral channel are realized in the inner-loop part of the overall structure of the waypoint following algorithm. The nonlinear simulation based on the TR-KUAV is carried out to evaluate the stability and performance of the algorithm. From the numerical simulation results, the algorithm shows very good tracking performance of passing the waypoints given. Especially, it is observed that ACAH/RCAH logic in the inner-loop has the satisfactory performance due to adaptive neural network in spite of the model error coming from the linear model based inversion.

• Journal of the Korean Society of Visualization
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• v.17 no.3
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• pp.46-51
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• 2019

Rotor wake interaction must be considered to understand the quadrotor flight, and the rotor separation distance is an important parameter that affects the rotor wake interaction. In this study, the wake characteristics were investigated with varying the rotor separation distance. The velocity field in the rotor wake was measured using digital PIV for hovering mode at Re = 34,000, and the wake boundaries from the inner and outer rotor tips were quantitatively compared with varying the rotor separation distance. The symmetric rotor-tip vortex shedding about the rotor axis was found at a large rotor separation distance. However, the wake boundary became more asymmetric about the rotor axis with decreasing the rotor separation distance. At the minimum rotor separation distance, in particular, a faster vortex decay was observed due to a strong vortex interaction between adjacent rotors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.445-446
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.333-334
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.777-778
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.779-780
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• 2008