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Obstacle Avoidance of A Mobile Robot Using A Calibrated Computer Vision System
트란안킴(Anh Kim Tran),김광주(Kwang Ju Kim),김학경(Hak Kyeong Kim),충탄람(Tan Lam Chung),김상봉(Sang Bong Kim) 한국동력기계공학회 2004 한국동력기계공학회 학술대회 논문집 Vol.- No.-
The obstacle avoidance task that is assigned to a mobile robot is addressed in this paper. A path planning method, namely polynomial path planning approach, is employed to generate a collision-free trajectory. It is clear that the path varies according to environment structure. Then, by applying a nonlinear feedback control law, the MR is able to track the smooth polynomial path in order to reach a target point. The information needed for the designed controller can be obtained via a computer visioning system with a ceiling-mounted USB camera. Because the computer vision system is capable to determine the position of any interesting points or objects in the work-space, the system can serve for MR's navigation and localization tasks as well. The practical realization is done through the hardware and software design using PICI6F877 chip. That is, the vision and navigation controls are parts of high level while the device control with PIC chips are considered as low level controllers. The low level control is known as a PIC-based servo controller communicating with its high level counterpart using wireless protocol. Also, the experimental results show quite good performance with acceptable tracking errors.
Sang-Bong Kim(김상봉),Huy Hung Nguyen,Dae-Hwan Kim(김대환),Hak-Kyeong Kim(김학경) 제어로봇시스템학회 2018 제어·로봇·시스템학회 논문지 Vol.24 No.6
This paper proposes a robust servo controller deign for MIMO systems based on a linear shift invariant differential(LSID) operator and its inverse operator on Schwartz space using the internal model principle(IMP). To do this task, the followings are done. First, the basic concept idea of LSID operator and its invertible operator are described. Furthermore, the IMP is rearranged based on LSID operator and the IMP is modified by the properties of the LSID operator. Second, an extended system operated by the LSID operator to a given MIMO system with the given reference is obtained. Third, the controllability checking of extended systems is done. Fourth, a state feedback law is obtained by solving the pole assignment problem with all the poles of the extended system. Fifth, The proposed controller is applied for controlling the sideslip angle and yaw rate of a 4-wheel steering vehicle as a MIMO system with 2inputs of steering angles of front and rear wheels and two outputs of the sideslip angle and yaw rate. Finally, simulation results are shown to verify the effectiveness of the proposed controller.
Fuzzy Control of Omnidirectional Mobile Plaform for Tracking the Curved Path
김상봉(Sang Bong Kim),Thinh Phuc Doan,김학경(Hak Kyeong Kim) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.4
In this paper, a simple algorithm based on fuzzy logic is applied to control an omnidirectional mobile platform (OMP) tracking a desired trajectory at a given desired bounded velocity. Tracking trajectory is a black line on the floor. An error configuration including angle error, distance error and velocity error is defined and measured by camera sensor. The motion of OMP is separated into three kinds of moving such as rotational moving, horizontal moving and vertical moving. Its movings are controlled independently. The proposed controller is designed by using PID fuzzy control method. The simulation and experimental results are presented to illustrate effectiveness and applicability of the proposed controller.
경사면 이동도립진자의 안정화를 위한 슬라이딩 모드 제어기 설계
김상봉(Sang-Bong Kim),김대환(Dae-Hwan Kim),최락순(Nak-Soon Choi),김학경(Hak-Kyeong Kim) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.4
This paper presents a sliding mode controller to stabilize the mobile inverted pendulum and an inclined plane which can move forward and backward and tum. The derived nonlinear dynamic modeling of the mobile inverted pendulum is linearized. The decoupling method is also presented to control the rotation around z axis independently of the rotation around y axis. It transforms torques of y and z axis into the wheel torques. To design the sliding mode controller, a switching function is defined based on a sliding surface matrix. The sliding surface matrix is designed based on an optimal control theory to minimize the quadratic performance. A control law is designed using reachability conditions to the sliding surface. The angle of the mobile inverted pendulum is measured using the gyro sensor and the accelerometer. The complementary filter is designed to compensate a gyro sensor's accumulative error. Finally the simulation and experimental results are shown to prove the effectiveness of the proposed controllers.
김상봉(Sang-Bong Kim),박철한(Chul-Han Park),김학경(Hak-Kyeong Kim) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.4
This paper proposes a new concept of inspection robot for adjusting to pipeline with variable diameter and driving in elbow. A proposed inpipe inspection robot has three wheeled linkage leg mechanism spaced in 120°. The inpipe inspection robot consists of front unit and back unit. This mechanism makes driving wheels be contacted with inner wall of pipelines of the elbow. Adjusting to pipeline with variable shape of the inpipe inspection robot is achieved by spring that is installed to its body. The three infrared sensors are located in front of the inpipe inspection robot triangularly to measure distances from the front of the inpipe inspection robot to the inner wall of pipeline. The algorithm is developed by using a infrared sensor that measure between the front unit and the inner surface of elbow. The simulation and experiment are given to demonstrate the effectiveness of the proposed algorithm.
Nguyen Van Lanh,Sung-Won Kim(김성원),Dae-Hwan Kim(김대환),Choong-Hwan Lee(이충환),Hak-Kyeong Kim(김학경),Sang-Bong Kim(김상봉) 제어로봇시스템학회 2019 제어·로봇·시스템학회 논문지 Vol.25 No.12
This paper proposes a multi-input multi-output (MIMO) robust servo controller design for three-wheeled Omnidirectional Automated Guided Vehicles (OAGVs) with a disturbance to track desired references using a linear shift invariant differential (LSID) operator. To design the proposed MIMO robust servo controller, the followings are performed. Firstly, a MIMO model of a threewheeled OAGV is presented. Secondly, by operating the LSID operator according to a state-space model and an output error vector, a new extended system and a new control law are obtained. Thirdly, the proposed MIMO robust servo controller for the given threewheeled OAGV is designed by using the pole assignment approach. Fourthly, by applying the inverse LSID operator, a servo compensator and a control law for the MIMO system are obtained. Finally, to verify the effectiveness of the proposed MIMO robust servo controller, the numerical simulation and experimental results are presented. The simulation and experimental results demonstrate that the proposed MIMO robust servo controller has adequate tracking performance under an external disturbance and complicated higher-order reference signals such as step, ramp, and parabola. These results are compared with those of the sliding mode control method proposed by N. Hung in 2010. The proposed MIMO robust servo controller demonstrates faster tracking performance than the sliding mode control method.
Jotje Rantung,Jong Min Oh(오종민),Hak Kyeong Kim(김학경),Sea June Oh(오세준),Sang Bong Kim(김상봉) 제어로봇시스템학회 2018 제어·로봇·시스템학회 논문지 Vol.24 No.2
This paper proposes the real-time image segmentation and determination of 3D coordinates for fish surface area and volume measurements based on stereo vision. The segmentation process is performed in real-time on the video frame. Complexity and computation time are reduced by segmenting hue and value feature spaces separately before combining result. Morphological erosion and morphological dilation are applied to remove any object pixels that are clustered as background pixels. Finally, image segmentation is obtained in the binary image of an object. A step-by-step approach to computing a binary image is applied to obtain segmentation image. The object is considered a fish on a platform with a known background color, a known geometric shape for the fish, and the stereo camera is in fixed position to capture an image. The objective of this paper is to obtain a simple but accurate 3D image that is capable of capturing the 3D coordinates values of the fish object. The followings are done for this task: First, the stereo camera is calibrated to collect its intrinsic parameters and distortion parameters correctly. Second, an image is captured by the camera, that is segmented in real-time to distinguish between the object’s destination and its surroundings. Finally, the object coordinates, surface area, and volume of the fish are measured. Experiment results show that the proposed method has good results in real-time segmentation, and shows different surface areas and volumes within about 6% and 5.3%, respectively.