• ETRI Journal
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• v.38 no.6
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• pp.1218-1228
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• 2016

This paper proposes a robot hand for a violin-playing robot and introduces a newly developed robot finger. The proposed robot hand acts as the left hand of the violin-playing robot system. The violin fingering plays an important role in determining the tone or sound when the violin is being played. Among the diverse types of violin fingering playing, it is not possible to produce vibrato with simple position control. Therefore, we newly designed a three-axis load cell for force control, which is mounted at the end of the robot finger. Noise is calculated through an analysis of the resistance difference across the strain gauge attached to the proposed three-axis load cell. In order to ensure the stability of the three-axis load cell by analyzing the stress distribution, the strain generated in the load cell is also verified through a finite element analysis. A sound rating quality system previously developed by the authors is used to compare and analyze the sound quality of the fourth-octave C-note played by a human violinist and the proposed robot finger.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.160-163
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• 1993

In this paper, design of an automatic grinding robot system for car brazing bead is introduced. Car roof and side panels are joined using brazing, and then the brazing bead is processed so that the bead is invisible after painting. Up to now the grinding process is accomplished manually. The difficulties in automation of the grinding process are induced by variation of position and shape of the bead and non-uniformity of the grinding area due to surface deformation. For each car, the grinding area including the brazing bead is sensed and then modeled using a 2-D optical sensor system. Using these model data, the position and the direction of discrete points on the car, body surface are obtained to produce grinding path for a 6 degrees of freedom grinding robot. During the process, it is necessary to sense the reaction forces continuously to prepare for the unexpected circumstances. In addition, to meet the line cycle time it is necessary to reduce the required time in sensing, signal processing, modeling, path planning and data transfer by utilizing real-time communication of the information. The key technique in the communication and integration of the complex information is obtaining in-field reliability. This automatic grinding robot system may be regarded as a jump in the intelligent robot processing technique.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.109.1-109
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• 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.

• 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.

• The Journal of Korea Robotics Society
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• v.15 no.4
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• pp.375-384
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• 2020

Today's robots consist of many hardware and software subsystems, depending on the functions needed for specific tasks. Integration of subsystems can require a great deal of effort, as both the communication method and protocol of the subsystem can vary. This paper proposes an expandable robotic system in which all subsystems are integrated under Robot Operation System (ROS) framework. To achieve this, the paper presents a software library, ROS_M, developed to implement the TCP/IP-based ROS communication protocol in different control environments such as MCU and RT kernel based embedded system. Then, all the subsystem including hardware can use ROS protocol consistently for communication, which makes adding new software or hardware subsystems to the robotic system easier. A latency measurement experiment reveals that the system built for loop control can be used in a soft real-time environment. Finally, an expandable mobile manipulator robot is introduced as an application of the proposed system. This robot consists of four subsystems that operate in different control environments.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.7
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• pp.591-597
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• 2001

In this paper, we propose a method of cooperative control (T-cell modeling) and selection of group behavior strategy (B-cell modeling) based on immune system in distributed autonomous robotic system (DARS). Immune system is living body's self-protection and self-maintenance system. These features can be applied to decision making of optimal swarm behavior in dynamically changing environment. For applying immune system to DARS, a robot is regarded as a B-cell, each environmental condition as an antigen, a behavior strategy as an antibody and control parameter as a T-cell respectively. The executing process of proposed method is as follows. When the environmental condition changes, a robot selects an appropriate behavior strategy. And its behavior strategy is stimulated and suppressed by other robot using communication. Finally much stimulated strategy is adopted as a swarm behavior strategy. This control school is based on clonal selection and idiotopic network hypothesis. And it is used for decision making of optimal swarm strategy. By T-cell modeling, adaptation ability of robot is enhanced in dynamic environments.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.167-169
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• 2011

Construction Automation as a way to solve the problems of lack of skilled labor by decrease in construction population productivity and quality decrease. We are on the way to develop a construction automation system adequate for domestic circumstances in Korea; it is called RCA(Robotic-crane based Construction Automation) system. Climbing hydraulic robot system is a part of RCA system and makes Construction Factory(CF) climb next floor. The controller can control movement needs to be developed for CF safety. Synchronous control the actual field was applied to the controller logic and synchronous control of the process through which the safety has been verified. The purpose of this study that control of climbing hydraulic robot system behavior on real-time, and to improve safety for overall construction automation system through synchronous motion controller.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.9
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• pp.788-794
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• 2002

To improve surgical result of total hip arthroplasty (THA), there has been some approaches using a robotic milling system, which can make a precise cavity in the femur. Usually, to carve a femur, the surgical robot is controlled by a pre-programmed tool-path regardless of a surgeon's experience and Judgment. This paper presents a control method of a surgical robot for THA, which can be used as an advanced surgical tool. With a master/slave combined surgical robot, surgeon can directly control the motion and velocity of a surgical robot. The master/slave-combined robot is controlled to display a specific admittance for a surgeon's force to the surgical robot velocity. To prevent the over-carving of a femur, virtual hard wall is displayed on the surgical boundary. To evaluate the proposed control method of the master/slave-combined surgical robot, 2-DOF master/slave-combined manipulator is used in experiment.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.12
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• pp.1238-1245
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• 2014

This paper proposes an RBFN-based adaptive tracking controller for an electrically driven mobile robot with parametric uncertainties and external disturbances. A mobile robot model considered in this paper includes all models of the robot body and actuators with uncertain kinematic and dynamic parameters, and uncertain frictions and external disturbances. The proposed controller consists of an RBFN(Radial Basis Function Network) and a robust adaptive controller. The presented RBFN is used to approximate unknown nonlinear robot dynamic functions. The proposed controller is adjusted by the adaptation laws obtained through the Lyapunov stability analysis. The proposed control scheme does not a priori need the accurate knowledge of all parameters in the robot kinematics, robot dynamics and actuator dynamics. Also, nominal parameter values are not required in the controller. The global stability of the closed-loop robot control system is guaranteed using the Lyapunov stability theory. Simulation results show the validity and robustness of the proposed control scheme.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.3
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• pp.201-206
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• 2000

In this paper, a posture control for nonholonomic mobile robots is proposed with an empirical basis. In order to obtain fast and consecutive motions in realistic applications, the motion requirements of a mobile robot are defined. Under the assumption of a velocity controller designed with the selection guidance of control parameters, the algorithm of posture control is presented and experimentally demonstrated for practicality and effectiveness.