• 제어로봇시스템학회:학술대회논문집
• /
• 1994.10a
• /
• pp.283-288
• /
• 1994

The adaptive control and the robust control have been considered as the most influential methods for robotic motion control. The purpose of this paper is to compare control performance between these two strategies in unconstrained motion control of robot manipulator. In order to compare control performance properly, intensive experiments are required and only then can conclusions be drawn on the relative merit and demerit of the controllers. Firstly, the control algorithms for unconstrained motion control are summarized. In adaptive control, the controllers that have been proposed so far are classified according to the signals used for the computed control input. It enables rather easier to compare controller is examined to demonstrate control performance of robust controllers. Finally, the above two approaches, the adaptive and the robust are compared from the view-point of robustness to plant uncertainty, which is one of the most demanding properties in robot motion control.

• Journal of Institute of Control, Robotics and Systems
• /
• v.4 no.1
• /
• pp.100-104
• /
• 1998

A hybrid control method based on the relative motion between a manipulator and a workpiece is described for a two-dimensional manipulator, in which it is assumed that there are no collisions between the robot manipulator and the workpiece, and that we use a computed force law which is similar to the computed torque law in the trajectory tracking problem of a robot manipulator. The effectiveness of the proposed hybrid control method is illustrated through several simulations.

• Progress in Medical Physics
• /
• v.33 no.4
• /
• pp.136-141
• /
• 2022

Purpose: This study aimed to develop a breath control training system for breath-hold technique and respiratory-gated radiation therapy wherein the patients can learn breath-hold techniques in their convenient environment. Methods: The breath control training system comprises a sensor device and software. The sensor device uses a loadcell sensor and an adjustable strap around the chest to acquire respiratory signals. The device connects via Bluetooth to a computer where the software is installed. The software visualizes the respiratory signal in near real-time with a graph. The developed system can signal patients through visual (software), auditory (buzzer), and tactile (vibrator) stimulation when breath-holding starts. A motion phantom was used to test the basic functions of the developed breath control training system. The relative standard deviation of the maxima of the emulated free breathing data was calculated. Moreover, a relative standard deviation of a breath-holding region was calculated for the simulated breath-holding data. Results: The average force of the maxima was 487.71 N, and the relative standard deviation was 4.8%, while the average force of the breath hold region was 398.5 N, and the relative standard deviation was 1.8%. The data acquired through the sensor was consistent with the motion created by the motion phantom. Conclusions: We have developed a breath control training system comprising a sensor device and software that allow patients to learn breath-hold techniques in their convenient environment.

• 제어로봇시스템학회:학술대회논문집
• /
• 1994.10a
• /
• pp.566-571
• /
• 1994

This paper presents in image-based visual servo control scheme for tracking a workpiece with a hand-eye coordinated robotic system using the fuzzy-neural-network. The goal is to control the relative position and orientation between the end-effector and a moving workpiece using a single camera mounted on the end-effector of robot manipulator. We developed a fuzzy-neural-network that consists of a network-model fuzzy system and supervised learning rules. Fuzzy-neural-network is applied to approximate the nonlinear mapping which transforms the features and theire change into the desired camera motion. In addition a control strategy for real-time relative motion control based on this approximation is presented. Computer simulation results are illustrated to show the effectiveness of the fuzzy-neural-network method for visual servoing of robot manipulator.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.37.2-37
• /
• 2002

1. Introduction 2. Problem Formulation 3. Avoidability Measure And Relative Distance 4. Artificial Potential Field in Terms of Relative Distance 5. Simulation Results 6. Conclusions 7. Reference

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.4
• /
• pp.49-58
• /
• 2003

In this study, the equation of motion of impacting elastic structures was derived through the theory, and the shape control of impact force using correlations of the dynamic characteristics and impact force history between two elastic structures was accomplished. Through numerical analysis and experiments, the classical contact mechanisms were verified, and the effects of the relative motion between impactor and elastic structure on the impact force shape were studied, and then the shape change of impact force depending on the impact position and mode shape of cantilever beam were analyzed. The 2-DOF impactor was designed and used. Reconstruction characteristics of impact force in cantilever beam were reviewed .

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.52 no.1
• /
• pp.1-8
• /
• 2003

In this paper, an observer-based adaptive controller is proposed to control the longitudinal motion of vehicles. The standard gradient method is used to estimate the vehicle parameters, mass, time constant, etc. The inter-vehicle spacing and its derivatives are estimated by using the sliding mode cascade observer introduced in this paper. It is shown that the proposed adaptive controller is uniformly ultimately bounded. It is also shown that the errors of the relative distance, the relative velocity and the relative acceleration asymptotically converge to zero. The simulation results are presented to investigate the effectiveness of the proposed method.

• Journal of KSNVE
• /
• v.7 no.3
• /
• pp.387-392
• /
• 1997

This paper concerns a SCARA robot with the flexible forearm linked to the rigid upper arm. The equations of motion are derived by the Lagrangian mechanics. For controller design, the perturbation approach is taken to separate the original equations of motion into linear equations describing small perturbed motions and nonlinear equations describing purely rigid motion of the robot. To effect the desired payload motion, open loop control inputs are determined based on the inverse dynamics of the latter. In order to reduce the positional error during maneuver, an active vibration suppression is done. To this end, a feedback control is designed for robustness against disturbance on the basis of the linear equations and the LQR theory modified to have a prescribed degree of stability. The proposed control scheme shows satisfactory performances in experiments as well as in numerical simulations.

• Journal of Ocean Engineering and Technology
• /
• v.34 no.2
• /
• pp.77-88
• /
• 2020

In this study, heading characteristics and heading control performances were evaluated to achieve the wave shield effect. The wave shield effect originating from heading control reduces the relative motions of moored vessels in a floating liquefied natural gas bunkering terminal (FLBT). Therefore, loading and off-loading performances are improved through reduced relative motion. For the objective of this study and efficiency of the analysis, a simplified model was used that assuming no relative motion of the moored vessels in the FLBT. The simplified model involved modeling the environmental loads and inertia of several floating bodies, including FLBT, into the environmental loads and inertia of a single vessel. The simplified model was validated through comparisons with model tests. With the simplified model, heading characteristics and heading control simulations were performed using low-frequency planar motion equations. The heading characteristics and heading control performances of FLBT were analyzed through the results of simulations under the expected environmental conditions. The capacity of the tunnel thrust for the heading control performance was confirmed to be adequate for improvement of the loading and off-loading performances using the wave shielding effects under the operation conditions.

• Journal of Astronomy and Space Sciences
• /
• v.25 no.3
• /
• pp.255-266
• /
• 2008

The current paper presents application of a new analytic solution in general relative motion to spacecraft formation flying in an elliptic orbit. The calculus of variations is used to analytically find optimal trajectories and controls for the given problem. The inverse of the fundamental matrix associated with the dynamic equations is not required for the solution in the current study. It is verified that the optimal thrust vector is a function of the fundamental matrix of the given state equations. The cost function and the state vector during the reconfiguration can be analytically obtained as well. The results predict the form of optimal solutions in advance without having to solve the problem. Numerical simulation shows the brevity and the accuracy of the general analytic solutions developed in the current paper.