• 제어로봇시스템학회논문지
• /
• 제17권12호
• /
• pp.1256-1265
• /
• 2011

Automated parking assist systems are being commercialized and rapidly spread in the market. In order to improve odometry accuracy, we proposed a practical odometry calibration scheme of Car-Like Mobile Robot (CLMR). However, there were some open problems in our prior work. For example, it was not clear whether the kinematic parameters always converged or not using the proposed calibration scheme. In addition, test driving had to be carried out "twice" without detailed explanation. This research aims to provide answers for the addressed questions though the convergence property analysis of the calibration scheme. In this paper, we evaluate on the effect of the kinematic parameter error on the odometry error at the final pose by numerical computation. The evaluation will show that the wheel diameter and tread of the CLMR can be calibrated by iterative test drives. In addition, the region of convergence in the parametric space will be discussed. Presented experimental results clearly showed that the proposed calibration scheme would be useful in practical applications.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.441-441
• /
• 2000

In wheeled mobile robot (WMR) research, point stabilization is one of the basic research issue. Point stabilization is to set mobile robot in desired position regardless of its orientation. In this paper, we propose a point stabilization scheme for car-like type WMR. We will define a new error states named as tangential error and nomal error. Then a heuristic control scheme will be suggested. The performance of these approach is verified via POSTUR-II.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.187-190
• /
• 1997

In the past few years, many researchers are interesting of control of mobile robot with nonholonomic constraints. And tracking problems is important as well as regulation in nonholonomic system control. Some researchers have investigated the stable tracking control law for mobile robot. But, few results showed the globally asymptotically stable control method simply. So, we address the design of globally asymptotically stable tracking control law for mobile robot with nonholonomic velocity constraints using simple method. The stabilizability of the controller is derived by Lyapunov direct method. And we analyze the system responses according to the variation of control parameters in line tracking problem. It is derived that the responses represent no overshoot property in line tracking. Examples are two-wheeled mobile robot and car-like mobile robot and the simulation results represent the effectiveness of our method.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
• /
• pp.511-515
• /
• 1996

A remote controlled mobile robot system has been developed and tested to monitor the radiation area in the nuclear power plant. The mobile robot system operates according to car-driving-like commands and is capable of radiation measurement and visual inspection in unmanned situations under radiation. The robot system is equipped with a radiation sensor and two cameras with appropriate illumination set-ups. The camera with auto-focus function and 8-times zoom lens is mounted on the pan/tilt rotational base and the other is mounted on the front panel of the robot system. All commands regarding the motion of the mobile robot and various sensors are given through the monitoring system which is designed to provide an integrated man-machine interface.

• 제어로봇시스템학회논문지
• /
• 제19권8호
• /
• pp.745-754
• /
• 2013

An efficient urban outdoor localization and navigation system is proposed for car-like robots. First an accurate outdoor localization method is suggested using line/arc features and 2.5D map matching with LRFs (Laser Range Finders), which can reduce the number of singular cases and increase accuracy. Also, path generation, path tracking, and path modification algorithms are proposed for navigation. All these algorithms are implemented on an electric scooter to construct an autonomous urban outdoor localization and navigation system. Experiments reveal the practicality of the proposed system.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
• /
• pp.23-26
• /
• 2000

Generally, the wheel-driven mobile robot systems, by their structural property, have nonholonomic constraints. These constraints are not integrable and cannot be written as time derivatives of some functions with respect to the generalized coordinates. Hence, nonlinear approaches are required to solve the problems. In this paper, the trajectory controller of wheeled mobile robot systems is suggested to guarantee its convergence to reference trajectory. Design procedure of the suggested trajectory controller is back-stepping scheme which was introduced recently in nonlinear control theory. The performance of the proposed trajectory controller is verified via computer simulation. In the simulation, the trajectory controller is applied to differentially driven robot system and car-like mobile robot system on the assumption that the trajectory planner be given.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.51.5-51
• /
• 2001

The sliding and/or skidding motions generally occur to a car - like planar mobile robot consisting of four conventional fixed wheels attached on two parallel axles. Thus, the kinematic model of such mobile robot should include the description of skidding and sliding frictional motions. However, most of previous kinematic models do not take these frictional motions into account the kinematic model, as the work done by Muir and Newman [1]. Thus, does it result in least square solution in estimating sensed forward velocity. In this paper, the sensed forward velocity estimation algorithm for mobile robots is proposed, which not only includes those skidding and sliding frictional motions into kinematic model but also utilizes only the minimal set of dependent internal kinematic variables of the mobile robot. Then, ...

• 제어로봇시스템학회논문지
• /
• 제17권10호
• /
• pp.995-1005
• /
• 2011

An efficient outdoor local localization method is suggested using multi-sensor fusion with MU-EKF (Multi-Update Extended Kalman Filter) for car-like mobile robots. In outdoor environments, where mobile robots are used for explorations or military services, accurate localization with multiple sensors is indispensable. In this paper, multi-sensor fusion outdoor local localization algorithm is proposed, which fuses sensor data from LRF (Laser Range Finder), Encoder, and GPS. First, encoder data is used for the prediction stage of MU-EKF. Then the LRF data obtained by scanning the environment is used to extract objects, and estimates the robot position and orientation by mapping with map objects, as the first update stage of MU-EKF. This estimation is finally fused with GPS as the second update stage of MU-EKF. This MU-EKF algorithm can also fuse more than three sensor data efficiently even with different sensor data sampling periods, and ensures high accuracy in localization. The validity of the proposed algorithm is revealed via experiments.

• 전자공학회논문지
• /
• 제51권10호
• /
• pp.180-189
• /
• 2014

본 논문은 무인 자동차의 자율주차 알고리즘 개발을 위하여 이 문제를 차량형 이동로봇의 위치-자세 안정화 (posture regulation) 문제로 치환하고 이렇게 치환된 문제를 해결할 수 있는 차량형 이동로봇을 위한 도킹 포메이션과 궤환선형화 제어기법을 제안한다. 경로생성 기법과 최적화 기법을 기반으로 하는 기존의 연구결과들에 비해, 본 논문에서 제안하는 자율주차 알고리즘은 자율주차 문제를 도킹 포메이션 기반의 위치-자세 안정화 문제로 치환하고 입력제한을 고려할 수 있는 궤환선형화 제어기법을 적용함으로써 적은 연산량과 낮은 성능의 프로세서만으로도 무인 자동차의 자율 주차가 가능하도록 한다. 본 논문에서 제안된 차량형 이동로봇의 도킹 포메이션과 궤환선형화 제어기법의 유효성은 안정성 해석을 통하여 보이고, 본 논문에서 제안하는 자율주차 알고리즘의 성능은 모의실험 및 실제 로봇을 통한 실험결과를 통하여 검증한다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.109.1-109
• /
• 2001

This paper deals with the path following problem of car-like intelligent mobile robot. A robust sliding mode control law based on time-varying state feedback is performed via Lyapunov method for path tracking of nonholonomic mobile robot with uncertainties. At first, A sliding control law is designed by combing the natural algebraic structure of the chained form system with ideas from sliding mode theory. Then, a robust control law is proposed to impose robustness against bounded uncertainties in path tracking. The problem of estimating the asymptotic stability region and the sliding domain of uncertain sliding mode system with bounded control input is also discussed. The proposed sliding mode control law can ensure the global reaching condition of the uncertain control system.