• Proceedings of the Korea Society for Simulation Conference
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• 2005.11a
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• pp.113-121
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• 2005

Virtual Manufacturing is a powerful methodology for developing a new product, new equipment and new production system. It enables us to check the errors in design before production. This paper deals with a case study of virtual manufacturing in an excavator factory. Boom and rotating table of upper body are selected for application. 3D models of parts and fixtures are developed with CATIA and 3D simulation models are developed with IGRIP. These models are used for the design of fixture to verify the motion of the equipment. As a result, the manual welding systems are replaced by automatic systems and many design errors are corrected in the design phase, which enables us to reduce the developing cost and time.

• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.759-760
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• 2012

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.437-440
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• 1988

This paper discuss which new dynamic control method for robot arm. It is basedon nonlinear feedback and T transformation which externally linearizes the whole system and provides simultaneous output decoupling. The nonlinear feedback augmented with optimal error correcting controller, which operates on the task error level. Computer simulation were appled to evaluate the performance of new dynamic control method. The simulation results are discussed in detail.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.147.3-147
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• 2001

We have proposed a digital control method, where the controlled variable is a joint angular velocity, of space robot manipulators using the transpose of Generalized Jacobian Matrix. The explicit relationship between the control law and the sampling period, however, is unknown because the controller gains include the sampling period implicitly. This paper presents a novel digital control method which explicitly describes the relation between the sampling period and the controller gains. Computer simulation of a 3-DOF planar space robot manipulator is peformed. Simulation result demonstrates the effctiveness of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.149.5-149
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• 2001

The robot soccer simulation game is a dynamic multi-agent environment. In this paper we suggest a new reinforcement learning approach to each agent´s dynamic positioning in such dynamic environment. Reinforcement learning is the machine learning in which an agent learns from indirect, delayed reward an optimal policy to choose sequences of actions that produce the greatest cumulative reward. Therefore the reinforcement learning is different from supervised learning in the sense that there is no presentation of input-output pairs as training examples. Furthermore, model-free reinforcement learning algorithms like Q-learning do not require defining or learning any models of the surrounding environment. Nevertheless ...

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1480-1484
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• 2004

In this paper, a self-propulsive and small concrete floor finishing trowel robot with twin trowels is proposed. Due to the small size and omni-directional moving capability, it is adequate for small space such as apartment. By adjusting the posture of trowels, it can move in any direction without wheels. We used cheap PIC processor for the cost saving design of the modules and adopted mode processors for easy operation of control stick. For the position control of the robot, we made a motion control algorithm appealing to the stepping motor driver module and the wireless communication module between the robot and PC (or control stick). In this paper, we discuss the control problem of the floor finishing robot in order to move to the right position. By comparing experimental result with simulation, we show the validity of the robot mechanism, sensors, and the control system.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.10
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• pp.902-911
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• 2012

This paper proposes a robust adaptive fuzzy backstepping control scheme for trajectory tracking of an electrically driven nonholonomic mobile robot with uncertainties and actuator dynamics. A complete model of an electrically driven nonholonomic mobile robot described in this work includes all models of the uncertain robot kinematics with a nonholonomic constraint, the uncertain robot body dynamics with uncertain frictions and unmodeled disturbances, and the uncertain actuator dynamics with disturbances. The proposed control scheme uses the backstepping control approach through a kinematic controller and a robust adaptive fuzzy velocity tracking controller. The presented control scheme has a voltage control input with an auxiliary current control input rather than a torque control input. It has two FBFNs(Fuzzy Basis Function Networks) to approximate two unknown nonlinear robot dynamic functions and a robust adaptive control input with the proposed adaptive laws to overcome the uncertainties such as parameter uncertainties and external disturbances. The proposed control scheme does not a priori require the accurate knowledge of all parameters in the robot kinematics, robot dynamics and actuator dynamics. It can also alleviate the chattering of the control input. Using the Lyapunov stability theory, the stability of the closed-loop robot control system is guaranteed. Simulation results show the validity and robustness of the proposed control scheme.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.8
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• pp.703-710
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• 2004

This paper presents discontinuous zigzag gait analysis for a newly modeled quadruped walking robot with an articulated spine which connects the front and rear parts of the body. An articulated spine walking robot can move easily from side to side, which is an important feature to guarantee a larger gait stability margin than that of a conventional single rigid-body walking robot. First, we suggest a kinematic modeling of an articulated spine robot which has new parameters such as a waist-joint angle, a rotate angle of a front and rear body and describe characteristics of gait using an articulated spine. Next, we compared the difference of walking motion of newly modeled robot with that of a single rigid-body robot and analyzed the gait of an articulated spine robot using new parameters. On the basis of above result, we proposed a best walking motion with maximum stability margin. To show the effectiveness of proposed gait planning by simulation, firstly the fastest walking motion is identified based on the maximum stride, because the longer the stride, the faster the walking speed. Next, the gait stability margin variation of an articulated spine robot is compared according to the allowable waist-joint angle.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.155-161
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• 2019

We introduces a mobile robot that can navigate on a power transmission line arranged in bundled conductors. The designs of the proposed robot are performed for navigation on bundled conductors, and the navigation method for bundled conductors and obstacle avoidance are presented. The robot consists of 13 degrees of freedom (DOF) with a symmetrical structure for the left and right parts, including the four wheel joints. The navigation method is designed using a combination of three motion primitives such as linear motion of counterbalancing box, linear motion of robot arm, and rotational motion of wheel part. To examine the performance of the proposed robot, navigation simulations are conducted using $ADAMS^{TM}$. The robot navigations were simulated on obstacle environments that consisted of two- and four-conductor bundles. Based on the simulation results, the performance of the proposed robot was reviewed through the analysis of the trajectories of end-effectors. We confirmed that the proposed robot was capable of achieving optimal navigation on bundled conductors that included obstacles.