• Title, Summary, Keyword: mobile linear system

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LPD(Linear Parameter Dependent) System Modeling and Control of Two Wheeled Mobile Robot

  • Kang, Jin-Shig
    • 제어로봇시스템학회:학술대회논문집
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    • pp.76.2-76
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    • 2002
  • Because of the wheeled mobile robot is modeled by nonlinear system framework and controlled by nonlinear algorithms or fuzzy algorithms, the treatment of wheeled mobile robot is very complecate and conservative. In this paper, a new model of two wheeled mobile robot, which is a type of linear system and treated easily, is presented. And we will show that the control algorithms based on the linear system theory is well work to the wheeled mobile robot by simulation and experiment.

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Study of a Two-wheel Mobile Robot with Linear Workspace Extension Structures (선형 작업 영역 확장 구조를 가진 두 바퀴 구동 모바일 로봇에 대한 연구)

  • Bae, Yeong-Geol;Jung, Seul
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.4
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    • pp.342-348
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    • 2015
  • This paper presents a two-wheel balancing mobile robot with linear workspace extension structures. The two-wheel mobile robot has two linear motions at the waist and shoulder to have extended workspace. The linear motion of the waist and shoulder provides some structural advantages. A dynamic equation of the simplified robot system is derived. Simulation studies of the position control of the robot system are performed based on the dynamic equations. The dynamic relationship between a two-wheel mobile system and linear extension mechanism is observed by simulation studies.

Performance Evaluation of Speech Coder for Digital Mobile Communication System in Radio Channel Environment (무선 채널 환경에서 디지털 이동통신용 음성 부호화기의 성능 평가)

  • 김형중;윤병식;최송인
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.1 no.1
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    • pp.77-83
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    • 1997
  • In this paper, we present a comparison between QCELP(Qualcomm Code Excited Linear Predictor) speech coder that is operating in digital mobile communication system and CS-ACELP(Conjugate Structure Algebraic Code Excited Linear Prediction) speech coder that is scheduled to use for IMT-2000 (International Mobile Telecommunications 2000) system. The performance comparison might give help to design of the speech coding algorithms so that the robustness of the algorithms to channel errors engaged by mobile communication system be optimized.

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A study on SLA(Scanned Linear Array) Applications for Mobile Communication Units (이동통신 단말기용 SLA(Scanned Linear Array) 적용에 관한 연구)

  • 김인회;안원석;문현찬
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.275-278
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    • 1998
  • In recent years, miniaturization has become the key factor in the development of mobile communication system. Portable communications and computing devices suffer from two conflicting requirements which are device size to be as small as possible and large, high resolution display. These problems can be solved by virtual display. Any display in which the user views an image through an optical system is a virtual display. It provides a display which is high resolution, appears large to the viewer and at the same time occupies little physical space. In this study, handhold units of mobile communication was investigated through use of the SLA(Scanned Linear Array). The basic SLA mechanism comprises a linear array of LED's, a magnifying lens, and a scan mirror. To optimize virtual image, we investigated optical system design and operating condition for each part.

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Study of Retention of Mono-Substituted Phenols in Reversed-Phase Liquid Chromatography Based on the Linear Solvation Energy Relationships Using the Solvatochromic Parameters for Mobile Phases, ${\pi}_m^{\ast}, {\alpha}_m$ and ${\beta}_m$

  • Park, Jung-Hag;Jang, Myung-Duk;Kim, Sang-Tae
    • Bulletin of the Korean Chemical Society
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    • v.11 no.4
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    • pp.297-302
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    • 1990
  • Retention of mono-substituted phenols in reversed-phase liquid chromatography has been studied based on the linear solvation energy relationships using the solvatochromic mobile phase parameters, ${\pi}_m^{\ast}, {\alpha}_m$ and ${\beta}_m$. It has been observed that retention behavior of phenols in RPLC were well represented by regression equations vs. solvatochromic mobile phase parameters even though the equations may be incomplete due to lack of an explicit cavity term. Dependence of retention of monosubstituted phenols on the mobile phase properties were varied depending on the type of the organic cosolvent in the mobile phase, e.g., ${\beta}_m$ and {\alpha}_m$ in methanol-water system, but ${\pi}_m^{\ast} and ${\beta}_m$ in THF-water system. It has been suggested that retention of phenols in methanol-water system is controlled by the solvophobicity of the mobile phase.

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Comparison of PID Controllers by Using Linear and Nonlinear Models for Control of Mobile Robot Driving System (모바일 로봇 구동 시스템 제어를 위한 선형 및 비선형 모델 기반 PID 제어기 성능 비교)

  • Jang, Tae Ho;Kim, Youngshik;Kim, Hyeontae
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.3
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    • pp.183-190
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    • 2016
  • In this study, we conduct linear and nonlinear modeling of the DC motor driving system of a wheeled mobile robot, which is a nonlinear system involving dead zone, friction, and saturation. The DC motor driving system consists of a DC motor, a wheel, and gears. A linear DC motor driving system is modeled using a steady-state response and parameter measurements. A nonlinear DC motor driving model is identified with the use of the Hammerstein-Wiener method. By using these models, PID controllers for the DC motor system are then established. Each PID controller is applied as a low-level controller in order to achieve posture stabilization control for the real mobile robot. We also compare the performance of the proposed PID controllers in posture stabilization experiments by using several different final robot postures.

Neural network based position estimation of mobile robot in slippery environment (Slip이 발생할 때 신경회로망을 이용한 이동로보트의 위치추정에 관한 연구)

  • 최동엽;조형석
    • 제어로봇시스템학회:학술대회논문집
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    • pp.133-138
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    • 1993
  • This paper presents neural network based position estimation method in slippery environment as an approach to solve one of problems which are engaged in dead reckoning method. Position estimator is composed of slip detector and linear velocity estimator. Both of them are based on the fact that dynamic characteristic of mobile robot in slippery environment is different from the case without slip. To find out the dynamic relation among driving torque, angular acceleration of driving wheel and linear acceleration of mobile robot, accelerometer is used for measuring acceleration of mobile robot and neural network is used for dynamic system identifier in slippery environment.

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Target Tracking Control of Mobile Robots with Vision System in the Absence of Velocity Sensors (속도센서가 없는 비전시스템을 이용한 이동로봇의 목표물 추종)

  • Cho, Namsub;Kwon, Ji-Wook;Chwa, Dongkyoung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.6
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    • pp.852-862
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    • 2013
  • This paper proposes a target tracking control method for wheeled mobile robots with nonholonomic constraints by using a backstepping-like feedback linearization. For the target tracking, we apply a vision system to mobile robots to obtain the relative posture information between the mobile robot and the target. The robots do not use the sensors to obtain the velocity information in this paper and therefore assumed the unknown velocities of both mobile robot and target. Instead, the proposed method uses only the maximum velocity information of the mobile robot and target. First, the pseudo command for the forward linear velocity and the heading direction angle are designed based on the kinematics by using the obtained image information. Then, the actual control inputs are designed to make the actual forward linear velocity and the heading direction angle follow the pseudo commands. Through simulations and experiments for the mobile robot we have confirmed that the proposed control method is able to track target even when the velocity sensors are not used at all.

Development of High Precision Docking Sensor for Mobile Robot (이동로봇을 위한 고정밀 도킹센서 개발)

  • Yoon, Nam-Il;Choi, Jong-Kap;Byun, Kyung-Seok
    • Journal of the Institute of Convergence Signal Processing
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    • v.12 no.4
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    • pp.348-354
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    • 2011
  • Mobile robots performed various missions in various environments. In order to move to target precisely, the mobile robots need a precise position sensing system In this paper, a new high precision docking sensor is proposed. Proposed docking sensor consists of linear CCD(charge coupled device) sensor and ultrasonic sensors. The docking sensor system can measure lateral position(X), longitudinal position(Y) and angle(${\theta}$) between the sensor and flat target with simple mark. Two ultrasonic sensors measure two distances which can be converted to longitudinal position and angle. Linear CCD sensor measures lateral position using center mark of the target. To verify performance of the sensor, the sensor is applied to an omnidirectional mobile robot. Several experimental results show highly precise performance of the sensor. Repeatability of the docking sensor is less than 1mm and $0.2^{\circ}$. Proposed docking sensor can be applied for precise docking of mobile robot.

Speech Quality Measure in a Mobile Communication System Using PLP Cepstral Distance with CMS (심리 음향 켑스트럼 평균 차감법을 이용한 이동 전화망에서의 음질 평가)

  • Yun, J.J.;Park, S.W.;Park, Y.C.;Youn, D.H.;Cha, I.H.
    • Speech Sciences
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    • v.6
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    • pp.163-179
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    • 1999
  • For the set up, management and repair of a mobile communication system, continuous estimation of speech quality is required. Speech quality measurement can be conducted by listener's judgement in a subjective test such as MOS (Mean Opinion Score) test. However, this method is laborious, expensive and time-consuming, it is advisable to predict subjective speech quality via objective measures. This paper presents a robust objective speech quality measure, PLP-CMS (Perceptual Linear Predictive-Cepstral Mean Subtraction), which can predict subjective speech quality in mobile communication systems. PLP-CMS has a high correlation with subjective quality owing to PLP (Perceptual Linear Predictive) analysis and shows a robust performance not being influenced by PSTN (Public Switched Telephone Network) channel effects due to CMS (Cepstral Mean Subtraction). To prove the performance of our proposed algorithm, we carried out subjective and objective quality estimation on speech samples which are variously distorted in a real mobile communication system. As a result, we demonstrated that PLP-CMS has a higher correlation with subjective quality than PSQM (Perceptual Speech Quality Measure) and PLP-CD (Perceptual Linear Predictive-Cepstral Distance).

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