http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Enhanced Operational Space Formulation for Multiple Tasks by Using Time-Delay Estimation
Pyung Hun Chang,Jae Won Jeong IEEE 2012 IEEE TRANSACTIONS ON ROBOTICS Vol.28 No.4
<P>The operational space formulation (OSF) has been enhanced from a practical viewpoint through the application of the time-delay estimation (TDE). In principle, the OSF enables an excellent decentralized control owing to its ability to achieve dynamic consistency. In reality, however, it can suffer from modeling errors and relatively large computational demands. As a remedy for these problems, the OSF has been combined with the TDE, which is known for its accurate estimation of robot dynamics with high computational efficiency. By virtue of the TDE, the OSF with the TDE (OSFTDE) shows enhanced accuracy in terms of dynamic consistency and control performance along with enhanced computational efficiency. Through simple but obvious simulations and experiments, the OSFTDE shows much better accuracy than the OSF with modeling error of 5% or higher, although accuracy is slightly worse than the OSF with a perfect model, thereby demonstrating its practical advantages.</P>
Pyung Hun Chang,Je Hyung Jung IEEE 2009 IEEE transactions on control systems technology Vol.17 No.2
<P>A systematic method to select gains of a discrete proportional-integral-derivative (PID) controller is presented. The PID controller with the gains obtained by the proposed method can robustly control nonlinear multiple-input-multiple-output (MIMO) plants in a second-order controller canonical form, such as robot dynamics. This method has been made possible by the finding that the discrete PID control is equivalent to the discrete form of time-delay control (TDC), a robust control method for nonlinear plants with uncertainty. By using this equivalence relationships are obtained between PID gains and parameters of TDC, which enable a systematic method for the select PID gains. In addition, based on the systematic method, a simple and effective method is proposed to tune PID gains applicable to nonlinear plants with inaccurate models. This method incorporates a set of independent tuning parameters that is far less than those for conventional methods for PID gain selection. The usefulness of the proposed methods is verified through the ease and simplicity of determining PID gains for six degrees-of-freedom (DOF) programmable universal machine for assembly (PUMA)-type robot manipulator; the effectiveness of these PID gains is confirmed by the adequate and robust performance through experimentation on the robot.</P>
Pyung Hun Chang,Kyungbin Park,Sang Hoon Kang,Krebs, H. I.,Hogan, N. IEEE 2013 IEEE/ASME transactions on mechatronics Vol.18 No.2
<P>Inspired by previous research on the promising internal model-based impedance control (IMBIC) scheme, it was implemented and experiments were undertaken to determine the stochastic estimation of human arm impedance. A 2-DOF selective compliant assembly robot arm (SCARA) robot with significant nonlinear frictions was used in the experiments in order to test the accuracy and reliability of the estimation under nonlinear frictions, with the IMBIC and with a proportional derivative (PD) control, respectively. After the stochastic estimation method with the SCARA robot and the IMBIC was validated using a spring array, the method was applied to the estimation of human arm impedance. The experimental results demonstrated that the stochastic estimation using the IMBIC yields accurate and reliable estimations even under substantial frictions: the multiple coherence functions exceeded 0.95 throughout the frequency range investigated and the estimated magnitudes and phases matched well with a second-order best-fit model. Furthermore, the best-fit model demonstrated reasonable agreement with the results of previous research. The stochastic estimation using the IMBIC has also demonstrated effectiveness in the estimation of human arm impedance using conventional robots.</P>
Pyung Hun Chang,Sang Hyun Park 한국과학기술원 인간친화 복지 로봇 시스템 연구센터 2007 International Journal of Assistive Robotics and Me Vol.8 No.3
This paper presents the development procedure of a robot arm to assist people with disabilities (PWD) at their work places and to promote their employment. The developed robot arm was shown to be highly useful through field testing. A target-oriented design (TOD) methodology was used for this procedure.