• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.157-160
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• 2002

When the teleoperation system has a signal transmission time delay between slave system and control system, the position tracking performance of the slave system and system stability are likely to be deteriorated. This paper proposes a force reflecting position control scheme for teleoperation system with signal transmission time delay. The proposed scheme not only satisfy the system internal stability but also improves the position tracking performance with disturbance rejection capability. The simulation results show that the proposed control method provides excellent performances.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.2846-2859
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• 1994

This work deals with kinematic analysis of fault-tolerant 3 degree-of-freedom spherical modules which have force redundancies in its parallel structure. The performance of a redundantly actuated four-legged module with no actuator failure, a single actuator failure, partial and half failure of dual actuator are compared to that of a three-legged module, in terms of maximum force transmission ratio, isotropic characteristics, and fault-tolerant capability. Additionally, a system with an excess number of small floating actuators is considered, and the contribution of these small actuators to the force transmission and fault-tolerant capability is evaluated. This study illustrates that the redundant actuation mode allows significant saving of input actuation effort, and also delivers a fault tolerance.

• Journal of Korean Association for Spatial Structures
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• v.20 no.4
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• pp.45-52
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• 2020

In this study, performance experiments were performed on the shape of steel dampers that affect the rocking behavior. Three types of strut shapes of SI type, SV type and SS type were considered as experimental variables. As a result of the experiment, the capacity to resist the moment and drift ratio according to the strut shape of the steel damper was evaluated as very close. Finally, it was evaluated that the SV type steel damper has stable deformation and energy dissipation capability. As a result of the evaluation of the proposed damper transmission force, it is considered that the damper transmission force is evaluated larger than the applied horizontal force, and it is necessary to supplement it.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.171-177
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• 2010

This paper presents the development of a new 6-DOF parallel-kinematic motion simulator. The moving platform is connected to the fixed base by six P-S-U (Prismatic-Spherical-Universal) serial chains. Comparing with the well-known Gough-Stewart platform-type motion simulator, it uses commercialized linear actuators mounted at the fixed base whereas a 6-UPS manipulator uses telescopic linear ones. Therefore, the proposed motion simulator has the advantages of easier fabrication and lower inertia over a 6-UPS counterpart. Furthermore, since most forces acting along the legs are transmitted to the structure of linear actuators, smaller actuation forces are required. The inverse position and Jacobian matrix are analyzed. In order to further increase workspace, inclined arrangement of universal joints is introduced. The optimal design considering workspace and force transmission capability has been performed. The prototype motion simulator and PC-based real-time controller have been developed. Finally, position control experiment on the prototype has been performed.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.116.1-116
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• 2002

When the teleoperated system has a signal transmission time delay between slave and control system , the system stability as well as the position tracking and the force reflecting performances are likely to be deteriorated. This paper proposed a bilateral control scheme and a controller design method for the teleoperated control systems with a signal transmission time delay. The proposed controller is a modified type of smith predictor for the time delay in each input and output stage of an open loop unstable plant. The proposed controller not only satisfies the system internal stability but also improves the position tracking performance with disturbance rejection capability. The simulation...

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.4
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• pp.422-434
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• 1997

In this paper, a two-stage kinematic optimal design for a 3 degree of-freedom (DOF) excavator subsystem, which consists of boom, arm and bucket, is performed. The objective of the first stage is to find the optimal parameters of the joint-actuating mechanisms which maximize the force-torque transmission ratio between the hydraulic actuator and the rotating joint. The objective of the second stage is to find the optimal link parameters which maximize the isotropic characteristic of the excavator subsystem throughout the workspace. It is illustrated that kinematic/dynamic performances of the kinematically optimized excavator subsystem have improved compared to those of original HE280 excavator, with respect to three performance indices such as maximum load handling capacity, maximum velocity capability, and acceleration capability.

• Journal of Ocean Engineering and Technology
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• v.24 no.3
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• pp.72-78
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• 2010

This paper presents a design approach of driving system for tidal flat vehicle. Firstly, topographic and geological survey of tidal flat zone was accomplished. 'Anac' located in the west-south coast of South Korea was chosen for the survey area. From the survey, the basic design data such as distribution of gullies size and bearing pressure was obtained. To figure out the shape of driving system, numerical simulations were carried out. Through the numerical dynamic simulations using $Recurdyn^{TM}$, the performance of various concepts of driving system was analyzed. From the results, we propose the conceptual design with the functions: a) low contact pressure, b) powerful driving force transmission, c) adaptation to the ground undulation. To satisfy these functional requirements, the driving system adopts rubber tracks, sprockets, tires and suspensions. The static structural analysis of the frame structure was executed as well, from which the detailed design was drawn out. To validate the performance of the designed driving system, the test vehicle which has gasoline engine of 27HP and mechanical transmission was constructed. The driving tests of the vehicle were performed twice at the "Anac" area, and unveiled its capability.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.45-53
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• 1998

Traction control systems(TCS) improve vehicle acceleration performance and stability, particularly on slippery roads through engine torque and/or brake torque control. This research mainly deals with the engine control algorithm based on adjustment of the engine throttle valve opening. Hardware-in-the-loop simulation(HWILS) is carried out where the actual hardware is used for the engine/automatic transmission and TCS controller, while various vehicle dynamics are simulated on real-time basis. Also, use of the dynamometer is made in order to implement the tractive force that a road applies to the tire. Although some restrictions are imposed mainly due to the capability of the synamometer, simplified HWILS results show that the slip control algorithm can improve the vehicle acceleration performance for low-friction roads.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.7
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• pp.758-768
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• 2005

The ball screw actuated by the electric motor is widely used as an essential actuator for driving the mechanical system by virtue of accuracy and force transmission capability. In this paper, a design of the global sliding mode control is presented to drive the ball screw actuator along the minimum time trajectory, In the proposed control scheme, if the ranges of parametric uncertainties and torque limits of the system are specified, the arrival time of the load along the minimum time trajectory can be estimated. Also, the arriving time at the reference input and the maximum acceleration are expressed in a closed form solution. Conversely, the capacity of a ball screw actuator including the motor can be easily designed if the external load and its transportation time are specified. The superior performance of the proposed control scheme and analysis is validated by the computer simulation and experiments comparing with other sliding mode controllers.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.5 s.143
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• pp.487-492
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• 2005

The structural intensity analysis, which calculates vibration energy flow from vibratory velocity and internal force of a structure, can give information on sources' power, dominant transmission path and sink of vibration energy. In this study, we present a system for structural intensity analysis and visualization to apply for anti-vibration design of ship structures. The system calculates structural intensity from the results of forced vibration analysis and visualize the intensity using a general purpose finite element analysis program MSC/Nastran and its pre- and post-processor program. To demonstrate the analysis and visualization capability of the presented system, we show and discuss the results of structural intensity analysis for a cross-stiffened plate and a 70,500 OW crude oil tanker