• IEMEK Journal of Embedded Systems and Applications
• /
• v.7 no.2
• /
• pp.61-70
• /
• 2012

This paper describes terrain-adaptive attitude controller for a hybrid mobile platform which operates in wheel & track mode. The wheel mode of the hybrid mobile platform allows quick driving performance in the flatland, while the track mode provides adaptive movement in the rough ground or stairway. The switching of the platform between two modes is automatically controlled by attitude controller algorithm. In addition, in the track mode, the platform automatically adjusts its attitude angle to overcome the obstacles in front. This paper demonstrates the attitude controller for the aforementioned wheel-track hybrid mobile platform in order to overcome terrain obstacles by using an adaptive method. The driving performance of the hybrid mobile platform has been tested and verified in various surrounding environments in both wheel and track mode. Further, this paper presents the experiments by using the track structure of mobile platform on forming adaptive attitude under various types of obstacles. The practicability and effectiveness of the proposed attitude controller of the platform has been demonstrated in urban building and a test-bed.

• Journal of the Korean Society of Industry Convergence
• /
• v.19 no.1
• /
• pp.18-30
• /
• 2016

In this paper, we propose a new technique to the design and real-time control of an adaptive controller for robotic manipulator based on digital signal processors. The Texas Instruments DSPs(TMS320C80) chips are used in implementing real-time adaptive control algorithms to provide enhanced motion control performance for dual-arm robotic manipulators. In the proposed scheme, adaptation laws are derived from model reference adaptive control principle based on the improved Lyapunov second method. The proposed adaptive controller consists of an adaptive feed-forward and feedback controller and time-varying auxiliary controller elements. The proposed control scheme is simple in structure, fast in computation, and suitable for real-time control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the proposed adaptive controller is illustrated by simulation and experimental results for a dual arm robot manipulator with eight joints. joint space and cartesian space.

• Journal of the Ergonomics Society of Korea
• /
• v.24 no.4
• /
• pp.73-78
• /
• 2005

As the number of functions in a menu increases, users have more difficulties in finding a desired function. Previous studies have shown that some functions are selected more frequently than others, and have suggested adaptive menus that support the selection of frequently used functions. Interestingly, studies on an adaptive toolbar are not easy to find as opposed to many studies on adaptive menus. This study suggested an adaptive toolbar (AT) that supported function selection, and conducted a usability test. Five or ten functions were presented in the AT according to the frequency of use or recency of use. A total of sixteen males in their twenties participated in the test. They freely selected functions from the menu or from the AT, and their pattern of selecting functions was analyzed. The results showed that the AT was more frequently used than the menu as time passed. The AT based on the recency of use showed more effective performance than that based on the frequency of use. In addition, keeping ten functions was better than five functions in terms of both performance and preference.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.39 no.4
• /
• pp.370-378
• /
• 2002

Fuzzy inference which combines numerical data and linguistic data has been used to design adaptive filter algorithms. In adaptive IIR filter design, the fuzzy prefilter is taken account, and applied to both direct and lattice structure. As for the fuzzy inference of the fuzzy filter, the Sugeno's method is employed. As membership functions and inference rules are recursively generated through neural network, the accuracy can be improved. The proposed adaptive algorithm, adaptive IIR filter with fuzzy prefilter, has been applied to adaptive system identification for the purposed of performance test. The evaluations have been carried out with viewpoints of convergence property and tracking properties of the parameter estimation. As a result, the faster convergence and the better coefficients tracking performance than those of the conventional algorithm are shown in case of direct structures.

• The Journal of the Acoustical Society of Korea
• /
• v.12 no.1
• /
• pp.37-46
• /
• 1993

The adaptive algorithm for the Volterra filter is considered. Owing to its simplicity, the LMS algorithm for adaptive Volterra filter(AVF) is widely used as in linear adaptive filters. However, the convergence speed is unsatisfactory. For improving the convergence speed, the frequency domain LMS second order adaptive Volterra filter(FLMS-AVF) is proposed and analyzed. We show that the time and frequency domain LMS AVF's have the same steady state performance under approprate conditons. Moreover, it can be shown that this algorithm can improve the convergence speed significantly by applying self-orthogonalizing method.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.8
• /
• pp.140-146
• /
• 1995

In case the uncertainty existing in a system is assumed to satisfy the matching condition and to be come-bounded. Y. H. Chen proposed an adaptive robust control algorithm which introduced adaptive sheme for a design parameter into robust deterministic controls. In this paper, the adaptive robust control algorithm is applied to the position tracking control of direct drive robots, and simulation and experimental studies are conducted to evaluate control performance.

• Journal of the Institute of Convergence Signal Processing
• /
• v.5 no.3
• /
• pp.216-222
• /
• 2004

Frequency selective fading is a limiting factor for transmission rate and performance in high-speed multimedia communications. In this paper, we propose a turbo coded adaptive quadrature amplitude modulation (QAM) system for efficient high-speed transmission. By making use of a user-friendly simulation platform of SPW, the proposed turbo coded adaptive QAM system(TuAQAM) is developed and its performance is evaluated in terms of throughput and BER performance. Two channel models having delay spreads of 700ns and 1400ns are created for the simulations. It is shown that the proposed TuAQAM system provides a performance improvement of approximately 3dB and improved throughput for the channel model whose delay spread is 700ns. Similarly, a performance improvement is also achieved for the channel model whose delay spread is 1400ns.

• Proceedings of the KIEE Conference
• /
• 2006.04b
• /
• pp.152-154
• /
• 2006

This paper investigates the adaptive control of a fuzzy logic based speed and flux controller for a vector controlled induction motor drive. A model reference adaptive scheme is proposed in which the adaptation mechanism is executed by fuzzy logic based on the error and change of error measured between the motor speed and output of a reference model. The control performance of the adaptive fuzzy controller is evaluated by simulation for various operating conditions. The validity of the proposed adaptive fuzzy controller is confirmed by performance results for induction motor drive system

• Journal of Advanced Navigation Technology
• /
• v.12 no.1
• /
• pp.22-27
• /
• 2008

This paper presents adaptive-MMOSPRED method for prediction of resource demands requested by multimedia calls, and shows the performance of the call admission control based on proposed resource prediction method in multimedia wireless networks. The proposed method determines (I-CDP) random variables of the standard normal distribution by using LMS algorithm that minimize errors of prediction in resource demands, while parameters in an existing method are constant all through the prediction time. Our simulation results show that prediction error in adaptive-MMOSPRED method is much smaller than in fixed-MMOSPRED method. Also we can see via simulation the CAC performance based on the proposed method improves the new call blocking performance compared with the existing method under the desired handoff dropping probability.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.7C
• /
• pp.907-914
• /
• 2004

In this paper, we propose an application of the receiver antenna switching to an conventional adaptive modulation system and derived the optimal antenna switching threshold of the system to maximize the average transmission bit rate and analyzed its performance. Also, we compare the performances of the presented scheme with those of an adaptive modulation using the antenna selection diversity and the one with a single antenna in terms of the average number of bits per symbol and the probability of no transmission. Performance comparison results show that the proposed system has an SNR gain of 1.4 dB over the adaptive modulation using a single antenna when the average number of bits per a symbol is two and yields an SNR gain of 6 dB for maintaining the probability of no transmission at the level of 0.1.