• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.10
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• pp.555-562
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• 2000

We propose an adaptive nonlinear control algorithm for compensation of the stick-slip friction in a dynamic system. The friction force and mass of the system are estimated and compensated by adaptive control law. Especially, as the nonlinear control input in a small tracking error zone is enlarged by the nonlinear function, the steady state error is significantly reduced. The proposed algorithm is a direct adaptive control method based on the Laypunov stability theory, and its convergence is guaranteed under the bounded noise or torque disturbance. We verified the performance of the proposed algorithm by computer simulation on one-DOF mechanical system with friction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.10
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• pp.1031-1038
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• 2007

A study on the development of control loading system for a pilot command in the helicopter flight training device is performed. The key issue of the device is how to provide closely the real feeling of the stick forces to the trainer during the flight training. Focusing on this proviso and considering the suitable approach than the complexity of the hydraulic system, we adopt the AC servo motor system although its inherent disadvantages such as the torque ripple and the stick-slip friction effect at a low control force. However, we overcome these detrimental effects by introducing the appropriate control device and the robust structural design of the actuating system, thereby the feasibility and applicability to the system can be obtained by showing good performance, meeting the required specification.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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• pp.335-341
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• 2016

In general, a yawing motion concept is used for the lateral control of one wheel robot where the gimbal system is located horizontally. In this paper, another concept of the vertically located gimbal system is presented for the same purpose. Although the vertical concept undergoes an instability more easily than the horizontal one, the pitching motion of the gyroscopic effect is considered. Firstly, the trade-off relation between two balancing concepts are investigated by comparing the gyroscopic mechanism. Secondly, the dynamic model for the problem of the proposed concept is derived using the oscillatory inverted stick model. Thirdly, the stability of the model is analyzed using the phase trajectory method. Finally, the control performance of the system by a vibration controller is simulated.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.5
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• pp.108-117
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• 1997

To prove the stability and the effectiveness of the robust non-linear friction control suggested and proved analytically in the previous paper, the describing function analysis is introduced. The instability of the Southward's nonlinear friction compensation for a digital position control and the improvement of phase margin of the robust nonlinear friction compensation are verified qualitatively through the describing function analysis. Those controls are applied to a single-axis digital servo driving experimental setup which has inherent stick-slip friction and experimental results confirm the results obtained in and the effectiveness of the robust nonlinear friction compensation for a digital position control.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.6
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• pp.45-51
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• 1995

This paper proposes a CMAC-based controller for servo systems with stick-slip friction. Performance of the controller was evaluated from computer simulations and compared with that of a conventional PID controller. Firction model used in the simulations is based upon the one proposed by Tustin. It was shown that the CMAC-based controller settles more quickly, and overshoots less than the PID. It was also shown that the CMAC is less sensitive to the changes of the plant parameters.

• Journal of Sensor Science and Technology
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• v.18 no.2
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• pp.154-159
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• 2009

This paper describes two methods - stamp-to-stick bonding and microtransfer molding - to integrate microfluidic channel into an optoelectrofluidic device for in-channel microparticle manipulation. We have demonstrated the optoelectronic microparticle manipulation in the channel-integrated optoelectrofluidic device using a liquid crystal display. As injecting a liquid sample containing $15{\mu}m$-diameter polystyrene particles into the fabricated channel, trapping and transport of individual microparticles have been successfully demonstrated. This channel-integrated optoelectrofluidic device may be useful for several in-channel applications based on the optoelectrofluidics such as optoelectronic flow control, droplet-based protein assay and bead-based immunoassay.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.4
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• pp.129-141
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• 2015

This study evaluates user experience of streaming stick service through usability testing. Streaming stick services such as Roku, Chromecast, and Everoncast were tested in ten levels belonging to five usability variables that are composed of efficiency of use, accuracy, meaningfulness, flexibility, and consistency. Each variable has two levels respectively that are responsiveness, minimal action, error prevention, error detection, error recovery, understandability, learnability, substitutivity, predictability, and familiarity in order. Twenty five participants volunteerly joined this research, and the results showed that Roku is superior to another two OTTs in most levels and variables. It implies that participants prefer to remote control, many channels, and personalized service during experiencing the service.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.150-155
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• 1999

비행 Simulator는 조종사가 실제 비행할 때와 같은 느낌을 받도록 구성되어야 하는데 조종사가 비행을 느끼게 되는 것은 여러 가지 감각기관을 통한 종합적인 느낌이다. 시각을 위하여 계기가 현재 비행 상태를 표시해야되고 외부 경치에서 고도, 속도, 자세 및 상승률을 감지하여야 한다. 이런 외부상태를 표시하기 위해서는 조종사의 Stick조작에 의한 비행기의 위치 변화와 속도 등을 실시간으로 계산하여 Graphic Engine과 Actuator로 데이터를 전송하여야 한다. 이러한 Parameter를 결정하기 위해서는 조정사의 조작에 의한 stick의 위치와 그로 인한 항공기의 자세 그리고 상태와 비행 속도 등에 따라 결정되며, 대상 항공기에 대한 제원으로 부터 조종사가 조종간의 이동크기와 조종면의 각 변위와의 관계를 계산하여 위치, 방향과 높이에 관한 Parameter를 계산해 줄 수 있는 방법 구현하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1120-1124
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• 2005

We reviewed controllers with a time delay estimation in this paper. Time delay control (TDC) and sliding mode control (SMC) are well known robust control schemes. Basically, the TDC has a main characteristic called a time delay estimation from which we can estimate the total uncertainty of a system. . The TDC causes the stick-slip in the case of systems with a friction. The so-called TDCSA which are short for TDC with switching action was developed to reduce the stick-slip. The TDC has the additional switching action term in the TDC structure. In the other hand, the SMC dose not have a time delay estimation but instead it can estimate the system uncertainty through the switching action. The SMC has a difficulty to estimate the total uncertainty of a system because it does not have a time delay estimation. In order to solve the difficulty, some control schemes were developed. Among them, we need to focus our attention on two control schemes: SMCPE and SMCTE, which are short for sliding mode control with a perturbation estimation and sliding mode control with a time delay estimation, respectively. In this paper, we analyzed and compared the characteristic of above three controllers. Even though the motives for the development of three control schemes are different, three control schemes have much in common in terms of their controller structures.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.6
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• pp.106-113
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• 1997

A new algorithm based upon TDC (Time Delay Control) is proposed to improve the robustness of TDC performance in systems where the stick-slip friction is strong. Experiments were performed at the different levels of friction. The reponses of the TDC and the modified TDC were compared each other, and against those of a PID controller with an anti-windup. The results show that the TDC and the modified TDC equally perform better than the PID, and that the modified TDC performs consistently well even with variations in the friction level while the TDC does not.