• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.90.6-90
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• 2002

An active stick which has the variable force-feel characteristics is developed. A combined position and force control strategy is mechanized using a 2-axis built-in force sensor and LVDT. The 2-axis force sensor which measures the stick force felt by the operator is developed by using strain gages and appropriate instrumental amplifiers. A mathematical model of the active stick dynamics is derived, and compared with the experimental results. The frictional torque of the stick due to the mechanical contacts of several parts makes the experimental frequency responses to be dependent on the magnitude of excitation signal, and the precision closed loop control to be difficult. A friction observe...

• 한국전자통신학회논문지
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• 제19권4호
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• pp.647-654
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• 2024

군 무기체계에서는 무장을 제어하기 위한 조종간이 필수적으로 사용된다. 본 논문에서는 RS-422 통신과 임베디드 프로세서를 이용하여 무장 조종간의 설계와 성능을 평가한다. 이 무장 조종간은 한국 조종사의 손 치수와 임무 편의성을 고려하여 인체공학적으로 디자인되었으며, RS-422 통신 기반의 회로와 소프트웨어는 임베디드 프로세서를 이용하여 설계되었다. 무장 조종간의 시제품을 제작하여 기본성능시험 및 고도, 고온, 저온, 온도충격, 습도, 강우, 진동 충격, 가속도 등 다양한 환경시험을 시행하여 기준을 충족하였다.

• 산업기술연구
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• 제24권B호
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• pp.207-214
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• 2004

An active stick which supplies force feedback to the operator is developed in this study. A mathematical model of the active stick is derived, and compared with the experimental result. It turns out that the frictional torque due to the mechanical contacts of several parts of the stick is one of the major barriers to achieve high precision operation of the stick. The frictional effect of the stick is cancelled out by using a friction observer. The efficacy of the friction observer is verified through the numerical simulation. Because of the observer dynamics, there are some limitations in exact recovering the static friction and Stribeck effect. However, the friction observer follows the real friction on the average. It's anticipated that the application of the friction observer to the closed loop control of the active stick improves the performance of the displacement versus force characteristics, which will be proved experimentally in the further study.

• Tribology and Lubricants
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• 제18권1호
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• pp.55-60
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• 2002

In many dynamic systems, there are unwanted oscillation which may arise the reduction of performance. Especially in low sliding speed condition, the stick-slip is an important issue because it because unstable motion as well as inaccurate position control in the system. Most previous works on the stick-slip are, however, only concerned with simple modeling under the condition of constant normal force. The normal force and the amount of hydraulic oil are variable with a cylinder stroke in the telescopic boom. This paper presents the pressure variations during stick-slip with the cylinder of telescope boom. Pressure variations by stick-slip has a similar pattern to that of single mass-spring model. The stick-slip is gradually decreased by means of increased flow rate.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.230-236
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• 2008

In this paper, a model-based stick-slip compensation for the micro-positioning is proposed using an enhanced stick-slip model based on statistical rough surface contact model. The smart structure is comprised with PZT (lead (Pb) zirconia (Zr) Titanate (Ti)) based stack actuator incorporating with the PID (Proportional-Integral-Derivative) control algorithm, mechanical displacement amplifier and positioning devices. For the stick-slip compensation, the elastic-plastic static friction model is used considering the elastic-plastic asperity contact in the rough surfaces statistically. Mathematical model of system for the positioning apparatus was derived from the dynamic behaviors of structural parts. PID feedback control algorithms with the developed stick-slip model as well as feedforward friction compensator are formulated for achieving the accurate positioning performance. Experimental results are provided to show the performances of friction control using the developed positioning apparatus.

• 한국소음진동공학회논문집
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• 제18권11호
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• pp.1134-1142
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• 2008

In this paper, a model-based stick-slip compensation for the micro-positioning is proposed using an enhanced stick-slip model based on statistical rough surface contact model. The smart structure is comprised with PZT(lead (Pb) zirconia(Zr) Titanate(Ti)) based stack actuator incorporating with the PID(proportional-integral-derivative) control algorithm, mechanical displacement amplifier and positioning devices. For the stick-slip compensation, the elastic-plastic static friction model is used considering the elastic-plastic asperity contact in the rough surfaces statistically. Mathematical model of system for the positioning apparatus was derived from the dynamic behaviors of structural parts. PID feedback control algorithms with the developed stick-slip model as well as feedforward friction compensator are formulated for achieving the accurate positioning performance. Experimental results are provided to show the performances of friction control using the developed positioning apparatus.

• 대한통합의학회지
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• 제12권3호
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• pp.121-130
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• 2024

Purpose : This study was conducted to investigate the effect of neck stabilization exercises using a stick on the pain, headache, and quality of life of adult patients with chronic non-specific neck pain. Methods : The participants of this study were 28 adult patients with chronic non-specific neck pain. The subjects were assigned to the experimental group (n=15, neck stabilization exercises using a stick after conservative physical therapy) and the control group (n=13, conservative physical therapy) according to the order of participation in the study and the intervention methods. The intervention was conducted three times a week for four weeks. The neck stabilization exercises using a stick consisted of isometric exercises of the muscles around the neck and strengthening exercises of the muscles around the scapula. The visual analog scale (VAS) and headache impact test (HIT-6) were used to measure the pain and headache, and the SF 36 health questionnaire (SF-36) was used to measure the quality of life. Results : In the comparison of VAS, HIT-6, and SF-36, there were significant differences between before and after the intervention in both the experimental and control groups (p<.05). The pre-post comparisons between the two groups according to the experiment showed significant differences between the experimental group and the control group (p=.001). However, the experimental group showed greater changes than the control group. Conclusion : Through this study, it was confirmed that neck stabilization exercises using a stick have positive effects on reducing the neck pain and headaches and improving the quality of life of adult patients with chronic neck pain. Therefore, it is considered that neck stabilization exercises using a stick can be used as an effective exercise method for the treatment and prevention of patients with chronic neck pain in the future.

• 한국간호교육학회지
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• 제21권2호
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• pp.168-181
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• 2015

Purpose: This study was conducted to determine the factors affecting the prevention of needle stick injury. Methods: Data collection was conducted during the period July 15-31, 2013 by a self-administered questionnaire involving 220 nurses working in 7 hospitals. The data was analyzed by SPSS v18 and AMOS v18. Results: Actions by nurses to prevent needle stick injury were directly and indirectly influenced by perceived benefits, attitude toward the behavior, perceived behavioral control, and intention underlying the behavior. Specially, perceived behavioral control is verified to have not only direct influence but also indirect influence on the performance of preventive action through the intention underlying the behavior. Also, perceived benefits indirectly influence the intention toward the behavior and performance of preventive action through attitude toward the behavior and perceived behavioral control. The predictor variables in this model are 52% explicable in terms of intention of prevention action against needle stick injury, and 66% explicable in terms of performance of preventive action. Conclusion: To ensure high performance of preventive action against needle stick injury, constructing not only the solution that inspires the intention toward behavior but also a system that can positively solve and improve obstructive factors in behavioral performance is of primary importance.

• Journal of Biosystems Engineering
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• 제36권6호
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• pp.467-475
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• 2011

Aerial spraying technology using a small unmanned helicopter is an efficient and practical tool to achieve stable agricultural production to improve the working condition. An attitude controller for the agricultural helicopter would be helpful to aerial application operator. In order to construct the flight controller, a state space model of the helicopter should be identified using a dynamic analysis program, such as CIFER$^{(R)}$. To obtain the state space a model of the helicopter, frequency-sweep flight tests were performed and time history data were acquired using a custom-built stick position transmitter. Four elements of stick commands were accessed for the collective pitch (heave), aileron (roll), elevator (pitch), rudder (yaw) maneuvers. The test results showed that rudder stick position signal was highly linear with rudder input channel signal of the receiver; however, collective pitch stick position signal was exponentially manipulated for the convenience of control stick handling. The acquired stick position and flight dynamic data during sweep tests would be analyzed in the followed study.

• 한국기계연구소 소보
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• 통권18호
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• pp.29-35
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• 1988

When low sliding velocities in the boundary lubrication range are operating, irregular movements frequently occur which are a result of the stick-slip phenomenon. Such slide motions are undesirable in precision machine tools, particularly with feed back systems used in numerical and adaptive control machine tools. Accordingly, this paper reports analytical and experimental studies in the stick-slip characteristic of machine tool feeding system. The main conclusions of this study are as follows; The tendency towards stick-slip effects may be reduced by; 1). Reducing the drop in friction coefficient in the Stribeck curve(on the rising part of the friction characteristic at higher sliding speeds, the system is stable all the time) 2). Reducing the transition velocity by the use of a higher viscosity lubricating oil. 3). Increasing the stiffness(Damping)and reducing normal load(Sliding mass) Therefore, the Critical velocity is decided from the above conclusions and in designing of machine tool, feed rates(sliding velocity)must be design the more than critical velocity.