• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.644-649
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• 2006

This paper presents a robust and superior control performance of a quarter-vehicle electrorheological (ER) suspension system. In order to achieve this goal, a moving sliding mode control algorithm is adopted, and its moving strategy is tuned by fuzzy logic. As a first step, ER damper is designed and manufactured for a passenger vehicle suspension system, and its field-dependent damping force is experimentally evaluated. After formulating the governing equation of motion for the quarter-vehicle ER suspension system, a stable sliding surface and moving algorithm based on fuzzy logic are formulated. The fuzzy moving sliding mode controller is then constructed and experimentally implemented. Control performances of the ER suspension system are evaluated in both time and frequency domains.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.8 s.113
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• pp.822-829
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• 2006

This paper presents a robust and superior control performance of a quarter-vehicle electrorheological (ER) suspension system. In order to achieve this goal, a moving sliding mode control algorithm is adopted, and its moving strategy is tuned by fuzzy logic. As a first step, ER damper is designed and manufactured for a passenger vehicle suspension system, and its field-dependent damping force is experimentally evaluated. After formulating the governing equation of motion for the quarter-vehicle ER suspension system, a stable sliding surface and moving algorithm based on fuzzy logic are formulated. The fuzzy moving sliding mode controller is then constructed and experimentally implemented. Control performances of the ER suspension system are evaluated in both time and frequency domains.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.509-512
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• 1995

A new modeling incorporating the role of control arm is proposed for the Macpherson type suspension system. Vertical displacement of the sprung mass and angular displacement of the control arm are selected as main control variables in the new modeling. With the same values of suspension vehicle parameters the conventional modeling and the new modeling are compared in terms of open loop characteristics.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.115.3-115
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• 2002

To improve the performance of the tracked vehicle system, we examined the feasibility of using the preview control for the tracked vehicles suspension system. We proposed a method to apply a linear optimal preview control to the tracked vehicle system. To avoid the complexity of modeling the track subsystem and kinematical nonlinearity in the trailing arm suspension, we classified these as unknown dynamics and disturbances. We used the Time Delay Control(TDC) method to make sprung mass dynamics follow that of linear preview controlled tracked vehicle model by compensating the uncertainties and disturbances. We have verified by the computer simulation that the proposed method shows good robus...

• Journal of Korean Medicine Rehabilitation
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• v.19 no.4
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• pp.19-35
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• 2009

Objectives : This experimental study was designed to investigate the effect of KangwhalSokdan-tang(Jianghuoxuduan-tang) on the muscle regeneration of atrophied rat muscle by hindlimb suspension. Materials and methods : In this study, Sprague-Dawley rats weighing about 250g were subjected to hindlimb suspension and divided into total four groups: Normal group(n=6), Control group(n=6), Hindlimb non-treatment group(n=6), Hindlimb treatment group(n=6). Experiments were seperately tried two times. The first trial was studied by the following two groups; The first was normal group(n=6). The second was group(n=18) for hindlimb suspension during 2 weeks (control I group). The second trial after 2 weeks hindlimb suspension was studied by the following three groups; The third group(n=6) was expired immediately after 2 weeks hindlimb suspension. The forth group(n=6) was given free activity during 2 weeks after 2 weeks hindlimb suspension. The fifth group(n=6) was administrated of KST during 2 weeks after 2 weeks hindlimb suspension. In order to investigate degree of muscle atrophy, body weight and gastrocnemius muscle mass were compared. To analyze muscle regeneration factors(expression of IGF-1, Myogenin, MyoD), Western blot was used. Results : The results were analyzed by statistical process as follows, 1. In body weight, all hindlimb suspension groups were lower than normal group, but tendency of increase was shown in KST group compared to non-treatment group after 2 weeks hindlimb suspension. 2. In gastrocnemius muscle mass, KST group on both side was significantly higher than non-treatment group after 2 weeks hindlimb suspension. 3. In case of IGF-I, Type I of KST group was significantly increased than non-treatment group, but Type II was not shown significance. 4. There was no significantly difference in Myogenin. 5. In MyoD, Type I of KST group was significantly increased than control group, and Type II of KST group was significantly increased than non-treatment group. Conclusions : In summary, this study demonstrates that KST administration has an effect to prevent muscle atrophy and contribute muscle regeneration and proliferation. And also it is suggested that IGF-I and MyoD is major factors of myogenesis expression to KST adminstration after hindlimb suspension.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.396.1-396
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• 2002

The AVT under traffic-induced vibrations was carried out on Namhae Suspension bridge in Korea. Mode shapes as well as natural frequencies up to the 15th mode were acquired exactly, and the effect of traffic mass and temperature on measured natural frequencies was investigated. The results from the AVT are compared with those from forced vibration test(FVT) and FE analysis. (omitted)

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.4
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• pp.266-273
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• 2003

The purpose of this study is to obtain the effects of the parameters of the suspension system in railway rolling-stock for KT-23 type Passenger vehicle. According to the analysis and the small scale model car test. optimal condition was obtained for the stiffness ratio of secondary spring to primary spring of the suspension system and the mass ratio of the bogie frame to the car body. The analysis of the study shows that if the car body mass is increased or secondary stiffness Is lowered, the vertical vibration level is reduced and the passenger comfort can be improved. Especially, strong peaks are occurred in the frequencies corresponding to the rotational speed of driving axle and vehicle wheel. Hence, in order to obtain the dynamic characteristics through the small scale model car, the driving method of the vehicle on the test bench, rotational characteristics of the wheel and the natural modes of vehicle should be investigated and be modified.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.3
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• pp.249-256
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• 2010

This paper presents performance analysis of a quarter-vehicle magneto-rheological(MR) suspension system with respect to different tire pressure. As a first step, MR damper is designed and manufactured based on the optimized damping force levels and mechanical dimensions required for a commercial mid-sized passenger vehicle. After experimentally evaluating dynamic characteristics of the manufactured MR damper, the quarter-vehicle MR suspension system consisting of sprung mass, spring, tire and the MR damper is constructed in order to investigate the ride comfort. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, vertical tire stiffness with respect to different tire pressure is experimentally identified. The skyhook controller is then implemented for the realization of quarter-vehicle MR suspension system. Ride comfort characteristics such as vertical acceleration RMS and weighted RMS of sprung mass are evaluated under various road conditions.

• Journal of Korean Academy of Nursing
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• v.25 no.2
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• pp.193-209
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• 1995

The purpose of this study was to determine the effect of intermittent low - intensity, short duration exercise during hindlimb suspension on the mass, relative weight, myofibrillar protein content, cross-sectional area of Type I and Type II fibers and SDH activity in Type II(plantaris) muscle. To examine the effectiveness of intermittent low-intensity, short duration exercise on mass, myofibrillar protein content and fiber size, the hindlimbs of adult female Wistar rats were suspended(HS) and half of these rats walked on a treadmill for 45 min/day(9 min every 2h) at 5m /min and a 15$^{\circ}$grade (HS-EX). Plantaris wet weight was 19.67% significantly smaller(p<0.005) and relative plantaris weight was 6.25% smaller compared with those of control rats following seven days of hindlimb suspension. Plantaris wet weight and relative plantaris weight increased by 27.66%, 12.22% each through intermit-tent exercise during hindlimb suspension(p<0.005, p<0.05), moreover, plantaris wet weight and relative plantaris weight of the HS-EX rats were similar to those of control rats. Soleus wet weight and relative soleus weight decreased significantly by 31% and 22.0% in the HS rats(p<0.05). Soleus wet weight and relative soleus weight increased by 10.41%, 25.64% respectively through intermittent ex-ercise during hindlimb suspension, furthermore, soleus wet weight and relative weight of the HS-EX rats were closer to those of control rats. Myofibrillar protein content of plantaris and soleus decreased significantly by 51.49%, 59.65% each, following seven days of hindlimb suspension (p<0.005) Myofibrillar protein content of plantaris and soleus increased by 51.79%, 75.47% each with significance through intermittent exercise during hindlimb suspension(p<0.005). Myofibrillar protein content of plantaris and soleus in HS-EX rats was smaller than that of control rats. No change was observed in fiber type percentage following 1 week of hindlimb suspension or exercise during hindlimb suspension. The type I fiber cross-sectional area of both soleus and plantaris muscle was 18.72% and 41.07% lower in the HS than that of the controls (p<0.05, p<.001), that of both muscles was 6.60% and 29. 3％ greater in the HS-EX than that of the HS rats. HS plus intermittent low- intensity short duration exercise resulted in Type I fiber cross-sectional area closer to the controls. Type II fiber cross-sectional area of both plantaris and soleus muscle was 22.45% and 22.58% sl nailer in the HS than in the controls, that of both muschles in the HS-EX was 14.10%, 5.78% greater than HS. Intermittent exercise during hindlimb suspension resulted in Type I, II fiber cross-sectional area closer to the control value. There was no change in SDH activity following 1week of hindlimb suspension or exercise during hindlimb suspension in the plantaris muscle. The results suggest that intermittent low intensity short duration exercise can ameliorate Type II muscular atrophy Induced by hindlimb suspension.

• Journal of Korean Academy of Nursing
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• v.22 no.3
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• pp.325-336
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• 1992

The purpose of this study was to determine the effect of exercise training on the length and circumference of atrophied muscles to see whether improvement in restoring the atrophied muscle mass, of either length or circumference growth could be induced through exercise training. Adult female Wistar rats were maintained for 14 days with hindlimb suspension. Rats were then assigned randomly to a sedentary group or training group. The length and circumference of both atrophied soleus and plantaris muscle for the training and sedentary groups following hindlimb suspension were compared with those of a control group. Length and circumference of both atrophied soleus and plantaris muscle in trained group was compared with those in the sedentary group. The results can be summarized as follows ; 1) Atrophy of soleus and plantaris muscle was induced with hindlimb suspension. 2) The circumference of both the soleus and plantaris muscle following hindlimb suspension was reduced to 51. 72%, 66.67% respectively compared to the control group. The length of both the soleus and plantaris muscle following hindlimb suspension did not show any difference compared to the control group. 3) There was no difference in length for either the atrophied soleus or plantaris muscle between the trained and the sedentary group during recovery from hindlimb suspension. 4) The circumference of both the atrophied soleus and plantaris muscle did not return to normal in the sedentary group, however, the circumference of both the atrophied soleus and plantaris muscle were significantly greater than of the control in the trained group, 14.22% and 9.38% respectively. 5) The circumference of both the atrophied soleus and plantaris muscle in the trained group was significantly larger than that of both muscles in the sedentary group at day 28 of recovery. From these results, it can be suggested that improvement in restoring the atrophied muscle mass through exercise training might be induced by growth of the muscle circumference.