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( Yuan Liang ),( Xinyu Da ),( Shu Wang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.11
In this paper, we propose a new scheme to suppress the narrowband interference (NBI) in OFDM-based systems. The scheme utilizes code division multiple access (CDMA) and weighted-type fractional Fourier transform (WFRFT) domain preprocessing technologies. Through setting the WFRFT order, the scheme can switch into a single carrier (SC) or a multi-carrier (MC) frequency division multiple access block transmission system. The residual NBI can be eliminated to the maximum extent when the WFRFT order is selected properly. Final simulation results show that the proposed system can outperform MC and SC with CDMA and frequency domain preprocessing in terms of the narrowband interference suppression.
Model Algorithmic Control for Multi-Input Nonlinear Time-delay System
Yuanliang Zhang(장원량),Kil To Chong(정길도) 제어로봇시스템학회 2008 제어로봇시스템학회 국내학술대회 논문집 Vol.2008 No.10
In this paper a digital controller for nonlinear MIMO system with time-delayed input is proposed. A nonlinear system with multi-input time-delay is discretized by using Taylor’s discretization method. And the discretized system can be converted to a general nonlinear system. For this reason, general nonlinear controller synthesis can be applied to the discretized time-delay system. We adopted MAC controller synthesis for this study. computer simulations are conducted to verify the performance of the proposed method. The results of simulation show good performance of the proposed controller synthesis.
Time-Discretization of Nonlinear Systems with Time Delayed Output via Taylor Series
Yuanliang Zhang,Chong Kil-To The Korean Society of Mechanical Engineers 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.7
An output time delay always exists in practical systems. Analysis of the delay phenomenon in a continuous-time domain is sophisticated. It is appropriate to obtain its corresponding discrete-time model for implementation via a digital computer. A new method for the discretization of nonlinear systems using Taylor series expansion and the zero-order hold assumption is proposed in this paper. This method is applied to the sampled-data representation of a nonlinear system with a constant output time-delay. In particular, the effect of the time-discretization method on key properties of nonlinear control systems, such as equilibrium properties and asymptotic stability, is examined. In addition, 'hybrid' discretization schemes resulting from a combination of the 'scaling and squaring' technique with the Taylor method are also proposed, especially under conditions of very low sampling rates. A performance of the proposed method is evaluated using two nonlinear systems with time-delay output.
Navigation of Mobile Robot Using Low-cost GPS
Yuanliang Zhang,홍동표 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.4
A method of fusing data from a Global Positioning System (GPS) and a Dead Reckoning (DR) system for outdoor navigation of aWheeled Mobile Robot (WMR) is proposed. The low-cost GPS receiver cannot be utilized by itself for navigating the mobile robot. Since, it produces an error of approximately 10-20 meters. DR can provide precise navigation data to the mobile robot but its errorsaccumulate over time. Since, all the previous data are utilized to calculate the current position information. DR needs to becomplemented by other navigation sensors to navigate the mobile robot. The proposed GPS/DR data fusion method is based on thecharacteristics of the single GPS receiver output. The fused data provides accurate and robust navigation information to the outdoormobile robot. Simulations were conducted using real GPS data which were then compared with the results using a Kalman filter thatverified the potential of the proposed GPS/DR data fusion method.
An GPS/DR Navigation System Using Neural Network for Mobile Robot
Yuanliang Zhang,정길도 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.12
Dead reckoning (DR) is frequently used for mobile robot navigation as it can provide precise short term navigation information butthe errors of a DR system can accumulate over time. A global positioning system (GPS) can be used for outside navigation andlocalization but the error of a single GPS receiver is still big even though an error intentionally introduced into the system called theselective availability policy (SA) was already removed. Standard differential GPS (DGPS) can provide an accuracy of less than onemeter but it is too expensive for the mass market aside from the need of having a base station to provide differential data. This paperproposes a new GPS/DR fusion method based on the data characteristics of a cheap single GPS receiver and use neural networkto estimate the output of the GPS receiver to provide precise navigation information to the mobile robot. Simulation results validatedthe performance of the proposed method and showed its potential use in outdoor mobile robot navigation.
A GPS/DR Data Fusion Method Based on the GPS Characteristics for Mobile Robot Navigation
Yuanliang Zhang,Kil To Chong 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.10
In this paper we have considered the problem of outdoor mobile robot navigation using dead reckoning (DR) system and single GPS receiver. DR is a very simple and practical positioning technique. It is used in various positioning and navigation applications, especially for the mobile robot. DR can provide short term precise navigation information. But its errors will generally accumulate as the mobile robot continues to travel, and the calculated position of the mobile robot will become less and less accurate. For outdoor navigation application, GPS exhibit lots of advantages. It can provide real time and relatively accurate position data in spite of bad weather or other negative factors. But the big errors of civilian used single GPS receiver prevent it from applying to navigation for mobile robot alone. Differential GPS (DGPS) can be used to achieve an error of less than one meter but the costs are prohibitive in terms of commercializing it into the mass market. In this study, a cheap single GPS receiver cooperated with a DR system was used for the navigation system of a outdoors mobile robot in which a new GPS/DR data fusion method was utilized. This proposed fusion algorithm was based on the characteristics of the chosen single GPS receiver. The presented fusion algorithm does not bring much calculation burden and can provide accurate and robust navigation information for the mobile robot by adaptively switching between GPS/DR and DR when GPS lost the satellite signals. Simulation and experiment were performed to validate the effectiveness of the proposed fusion method and the good results showed its potential for outdoors mobile robot navigation.