• Transactions on Control, Automation and Systems Engineering
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• v.4 no.1
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• pp.2-8
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• 2002

This paper discusses haptic display for grasping a virtual object by two fingers. Much research has been done on fundamental analysis for stability of haptic display. But it is difficult to apply the results immediately to grasping situations by two fingers, since the studies usually deal with a single device and a single object and the fingertip force in grasping situations has two components, internal and external components. The conventional methods, which specify the coupling impedance at each contact point separately, have no other alternative but to specify the impedance for the sum of the internal and external components. So even if only the impedance for the external force should be changed, the impedance for the internal force is also changed at the same time. In this paper, a new method, in which the coupling impedance is specified separately for the internal and external forces, is proposed and the stability of the proposed method is discussed using passivity analysis for 1 -DOF(Degree-Of-Freedom) system. Finally, some experiments are performed to study the effects of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2713-2718
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• 2003

Some of manufacturing tasks such as sawing task often requires continuous impulsive motion. In case of sawing task, such impulsive motions can be observed between the teeth of the saw and the object. The amount of the external impulse exerted on the object has been treated as an important control parameter. The purpose of this work is to introduce a new concept of an effective mass in sawing task and to suggest an external impulse model in sawing task. A normalized impulse ellipsoid reflecting the velocity direction is employed to visualize the impact geometry. Experiments are performed for soft and hard workpieces to justify the external impulse model in the sawing task. It is demonstrated through simulation and experiment that the proposed external impulse model is effective to characterize the impact property.

• Journal of Convergence for Information Technology
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• v.11 no.10
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• pp.68-73
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• 2021

This study was to identify the effects of using Gratitude Diary Writing on self-esteem and internal-external locus of control to adolescent. A randomized controlled experimental design was used. There were 20 participants in the experimental group, and 19 in the control group. Data were analyzed using Chi-square test, Fisher's exact test, t-test. The results of self-esteem(t=5.142, p=<.001) and internal-external locus of control(t=5.821 p=<.001)l showed statistically significant differences between the two groups. Using thank journal writing is effective in improving adolescents self-esteem and internal-external locus of control. If the gratitude diary writing effect of gratitude is verified by selecting a wide sample, it is expected that it will be helpful for generalize activities.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.660-666
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• 2023

This study aimed to examine the effect of external pop-up satellite archival tags (PSATs) attachment and water temperature on the oxygen consumption rate (OCR) of the olive flounder (mean body weight 2281.7 g). The OCRs of fish were measured under conditions of three different water temperature conditions (15, 20, and 25℃) and two different tagging methods [non-tagging, control; bio-logger external attachment with a miniature PSAT (dummy mrPAT), BEA] using a closed flow-through respirometer. The OCRs of fish linearly increased with the increase in water temperature in both the control and BEA (P<0.001); however, the OCRs of BEA were approximately 1.8-1.9 times lower than those of the control at each water temperature (P<0.001). The Q₁₀ values of the control and BEA were the highest in the water temperature range of 15 to 20℃, but sensitivity to water temperature changes was higher in BEA than in the control. The metabolic energy loss rate (MEL) of fish increased with increasing water temperature regardless of external tagging, but the MEL of the control was higher than that of BEA (P<0.001). These results demonstrate that OCR, thermal sensitivity, and energy expenditure are all affected in adult olive flounder with external PSAT attachment.

• Journal of Technology Innovation
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• v.11 no.1
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• pp.177-193
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• 2003

This paper examines empirically if the increase of funding uncertainty in government supported R&D institutes(GSRIs) in Korean cause managers to use more effective management control practices. Recently government introduced a new government R&D budget management system, based on competition, named PBS(Project Base System). Government requires GSRIs to be self-supporting and compete for funding from government. The introduction of new budget management system named PBS, has resulted in the increase of funding uncertainty in GSRIs. According to institutional theory, government organizations gain legitimacy by conforming to external expectations regarding management control practices, In contrast, contingency theory proposes that management control practices are driven by the fit between the technical features of the environment and the management control practices. The contingency literature provides that one external factor expected to motivate government managers to use more efficient control practices is the presence of competition and funding uncertainty. This paper use both theoretical perspective to develop hypotheses and examine the influence of funding environment on management control practices. Results show that the more institutionalized environment, the more managers in GSRIs rely on bureaucratic mode of control for conforming to external requirements, and the greater the funding uncertainty, the more managers use results and personal modes of control to improve research team performance.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1136-1140
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• 1993

A communication system in an industrial robot controlle is proposed for the implementation of an efficient FA system. Different from existing industrial robot controllers which use binary I/O for the communication with external systems, the robot controllers having the proposed communication system can exchange various information with external systems. Furthermore, the robot motion and the communication with external systems can be performed simultaneously. The structure of hardware and software in the communication system is explained to show how to acheive these two operations simultaneously.

• Journal of Drive and Control
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• v.13 no.3
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• pp.32-38
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• 2016

For this paper, the position-control performances of dual EHA(electro-hydrostatic actuator) systems were investigated according to two cases wherein the double-rod- and single-rod-type hydraulic cylinders were combined. Since the control performance is significantly dependent on the load conditions including external forces such as the inertia load, it is proposed here that the two sub-EHAs are driven by separate position and force controllers, instead of two identical position controllers. According to the simulation results, the best performance was achieved by the position-controlled single-rod-type EHA that was combined with a force-controlled double-rod-type EHA. As the force-controlled double-rod-type EHA compensated for the external loads on the position-controlled single-rod-type EHA, the position-control performance was not influenced by external forces including the inertia load. In addition, the position-controlled single-rod-type EHA contributed to the enhancement of the damping ratio by absorbing the pressure peaks through its internal accumulator. Due to the symmetrical piston areas, the double-rod-type EHA is more suitable for force control than the single-rod- type EHA.

• Journal of Power Electronics
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• v.16 no.2
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• pp.798-804
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• 2016

This paper proposes a new operation and control strategy for Power-Assisted Wheelchairs (PAW) using one brushless DC (BLDC) motor. The conventional electrical wheelchairs are too heavy and large for one person to move because they have two electric motor wheels. On the other hand, the proposed PAW system has a small volume and is easy to move due to the presence of a single wheel motor. Unlike the conventional electric wheelchairs, this structure for a PAW does not have a control joystick to reduce its weight and volume. To control the wheelchair without a joystick, a special control system and algorithm are needed for proper operation of the wheelchair. In the proposed PAW system uses only one sensor to detect the acceleration and direction of PAW's movement. By using this sensor, speed control can be achieved. With a speed control system, there are three kinds of operations that can be done on the speed of a PAW: the increment of PAW speed by summing external force, the decrement of PAW speed by subtracting external force, and emergency breaking by evaluating the time duration of external force. The validity of the proposed algorithm is verified through experimental results.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1212-1215
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• 2002

This paper proposes the system that automatically cognizes the external interface cards on control board. This system is proposed by this paper endows with ID to external interface card and cognizes a connection of external interface card. Also this system automatically executes a task for external interface card. This system has an extension of function according to cognize an external interface card and is fast the execution.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2271-2274
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• 2005

The desired ZMP is different from the actual ZMP of a humanoid robot during actual walking and stand upright. A humanoid robot must maintain its stable posture although external force is given to the robot. A humanoid robot can know its stability with ZMP. Actual ZMP may be moved out of the foot-print polygons by external disturbance or uneven ground surfaces. If the position of ZMP moves out of stable region, the stability can not be guaranteed. Therefore, The control of the ZMP is necessary. In this paper, ZMP control algorithm is proposed. Herein, the ZMP control uses difference between desired ZMP and actual ZMP. The proposed algorithm gives reaction moment with ankle joint when external force is supplied. 3D simulator shows motion of a humanoid robot and calculated data.