• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.587-590
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• 2003

In this paper, the control of the differential drive wheeled mobile robot (DDWMR) is studied. Because the DDWMR have non-holonomic constraints, it cannot be stabilized by smooth feedback. The T-S fuzzy model for the DDWMR is presented and a control algorithm Is developed by well known PID control and LMI based regional pole-placement.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.67.6-67
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• 2001

In this paper, we present an attitude control of self-standing for a two-wheeled inverted-pendulum-like mobile robot based on the nonlinear control theory. Nonlinear dynamic equations are linearized by using the Lie derivative, and a pole placement controller is designed. Characteristics of the controller are examined by numerical simulations to show the self-standing attitude of the mobile robot in standing and in moving.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.231-236
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• 1997

We propose the hybrid control for the path control of wheeled mobile robot system. To develop the hybrid control of mobile robot, the continuous dynamics of mobile robot are modeled by the switched systems. The abstract model and digital automata for the path control are developed. This hybrid control system has the 3-layered hierachical structure : digital automata as the higher process, mobile robot system as the lower process, and the interface as the interaction process between the continuous dynamics and the discrete dynamics. The control of following the desired-paths with edges are investigated as the applications by the computer simulation.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2693-2695
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• 2005

In this paper, we developed a more efficient system for the remote control and monitoring of a wheeled mobile robot using internet without spatial limitation. The hardware configuration of the remote control system for a wheeled mobile robot includes a client PC executed on the remote site, a embedded web-server and a mobile robot with many measuring equipments. The communication between a client PC and a embedded web-server is implemented through internet. And the Bluetooth module is used for connecting a embedded web-server and a mobile robot. A GUI program has been developed by using JavaScript in order to easily control a mobile robot on a client PC.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1245-1254
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• 2011

This paper proposes a target tracking algorithm for wheeled mobile robots using in various fields. For the stable tracking, we apply a vision system to a mobile robot which can extract targets through image processing algorithms. Furthermore, this paper presents an algorithm to position the mobile robot at the desired location from the target by estimating its relative position and attitude. We show the problem in the tracking method using the Position-Based Visual Servo(PBVS) control, and propose a tracking method, which can achieve the stable tracking performance by combining the PBVS control with Image-Based Visual Servo(IBVS) control. When the target is located around the outskirt of the camera image, the target can disappear from the field of view. Thus the proposed algorithm combines the control inputs with of the hyperbolic form the switching function to solve this problem. Through both simulations and experiments for the mobile robot we have confirmed that the proposed visual servo control method is able to enhance the stability compared to of the method using only either PBVS or IBVS control method.

• The Journal of Korea Robotics Society
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• v.15 no.3
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• pp.277-285
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• 2020

A differential drive wheeled robot is a kind of mobile robot suitable for indoor navigation. Model predictive control is an optimal control technique with various advantages and can achieve excellent performance. One of the main advantages of model predictive control is that it can easily handle constraints. Therefore, it deals with realistic constraints of the mobile robot and achieves admirable performance for trajectory tracking. In addition, the intention of the robot can be properly realized by adjusting the weight of the cost function component. This control technique is applied to the local planner of the navigation component so that the mobile robot can operate in real environment. Using the Robot Operating System (ROS), which has transcendent advantages in robot development, we have ensured that the algorithm works in the simulation and real experiment.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.183-190
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• 2022

Accurate kinematic parameters of mobile robots are essential because inaccurate kinematic model produces considerable uncertainties on its odometry and control. Especially, kinematic parameters of caster type mobile robots are important due to their complex kinematic model. Despite the importance of accurate kinematic parameters for caster type mobile robots, few research dealt with the calibration of the kinematic model. Previous study proposed a calibration method that can only calibrate double-wheeled caster type mobile robot and requires direct-measuring of robot center point and distance between casters. This paper proposes a calibration method based on geometric approach that can calibrate single-wheeled caster type mobile robot with two or more casters, does not require direct-measuring, and can successfully acquire all kinematic parameters required for control and odometry. Simulation and hardware experiments conducted in this paper validates the proposed calibration method and shows its performance.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.5
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• pp.118-125
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• 2002

The previous kinematic analysis of wheeled mobile robots(WMRs) is performed in an ad-hoc manner, while those of the robot manipulators are done in a consistent way using the coordinate system assignment and the homogeneous transformation matrix. This paper shows why the method for the robot manipulators cannot be used directly to the WMRs and proposes the method for the WMRs, which contains modeling the wheel with the Sheth-Uicker notation and the homogeneous transformation. The proposed method enable us to model the velocity kinematics of the WMRs in a consistent way. As an implementation of the proposed method, the Jacobian matrices were obtained for conventional steered wheel and non-steered wheel respectively and the forward and inverse velocity kinematic solutions were calculated fur a tricycle typed WMR. We hope that our proposed method comes to hold an equivalent roles for WMRs, as that of the manipulators does for the robot manipulators.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.113-123
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• 2000

In the navigation for a mobile robot, the collision avoidance with unexpected obstacles is essential for the safe navigation and it is independent of the technique used to control the mobile robot. This paper presents a new collision avoidance algorithm using neural network for the safe navigation of the autonomous mobile robot equipped with CAN and ultrasonic sensors. A tracked wheeled mobile robot has a stability and an efficiency to move on a rough ground. And its mechanism is simple. However it has difficulties to recognize its surroundings. Because the shape of the tracked wheeled mobile robot is a square type, sensor modules are generally located on the each plane surface of 4 sides only. In this paper, the algorithm using neural network is proposed in order to avoid unexpected obstacles. The important character of the proposed algorithm is to be able to detect the distance and the angle of inclination of obstacles. Only using datum of the distance and the angle, informations about the location and shape of obstacles are obtained, and then the driving direction is changed. Consequently, this algorithm is capable of real time processing and available for a mobile robot which has few sensor modules or the limited sensing range such as a tracked wheeled mobile robot. Effectiveness of the proposed algorithm is illustrated through a computer simulation and an experiment using a real robot.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.9
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• pp.845-853
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• 2012

We propose time-optimal cornering motion trajectory planning and control algorithms for differential wheeled mobile robot with motor actuating voltage constraint, under piecewise constant control input condition. For time-optimal cornering trajectory generation, 1) we considered mobile robot's dynamics including actuator motors, 2) divided the cornering trajectory into one liner section, followed by two cornering section with angular acceleration and deceleration, and finally one liner section, and 3) formulated an efficient trajectory generation algorithm satisfying the bang-bang control principle. Also we proposed an efficient trajectory control algorithm and implemented with an X-bot to prove the performance.