• The Journal of Korean Physical Therapy
• /
• v.21 no.3
• /
• pp.81-86
• /
• 2009

Purpose: This study compared the characteristics of the brake response time during the driving task between elderly and younger drivers. Methods: The participants consisted of an elderly group (n=12) and a younger group (n=12). The brake response time (BRT), which consisted of the reaction time (RT) and movement time (MT), was assessed in an actual driving car. The BRT was measured at the initiation and termination of the brake response for the driving task Results: The elderly group showed a significantly longer delay in the initiation and termination of the brake response than the younger group. The BRT correlated significantly with both the RT and MT. However, the RT showed a more significant correlation. Conclusion: A delay in the initiation and termination of the brake response may have clinical implications. A further study will be needed to determine the different factors contributing to the driving performance of elderly drivers.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.7
• /
• pp.535-540
• /
• 2016

The braking device in railway vehicles decelerates or stops the train by dissipating the thermal energy converted from kinetic energy into the air. Therefore, the brake system is crucial for safety. In this paper, we performed a study on an electromechanical brake actuator using an electrical motor as an alternative to pneumatic air cylinders to reduce the idle running time in braking, which subsequently increases braking distance, and to ensure reliable response characteristics. Especially, to analyze the response characteristics of the electromechanical brake actuator, we measure the delay time, response time and power consumption compared to the air cylinder. It is confirmed that the electromechanical brake actuator can reduce reaction time by 0.1 seconds (Braking Action) and 0.46 seconds (Brake Release) compared to the air cylinder.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.1069-1070
• /
• 2010

• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.261-264
• /
• 1997

A contactless eddy current type braking system is developed to take advantages of the recent brake system which uses hydraulic force can show high efficiency in a certain velocity region, but not in a high velocity region, and has initial response delay time and pressure build-up time which make stopping distance longer. These are the limits of mechanical brake system of a contact type, which makes a concept brake system required. So, in this paper, the contactless brake system .of a inductive current type is chosen instead of hydraulic brake system. This brake system can be used almost forever for being no wear and contributed to lightening weight of a vehicle. Besides, the contactless brake system can be used as that of electric or solar car with anti-lock brake system. The analysis of induced electromotive force and braking torque obtained with theoretical approximate model, the design of a braking system and a nonlinear controller, and the results of simulation of the ABS, experiment are included.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.5
• /
• pp.24-29
• /
• 2004

This paper presents the tension control of a wire-cut discharge machine using electrorheological(E,R) fluid based brake system. On the basis of the tension level required in the machine, an appropriate size of the ER brake which features design simplicity, fast response and salient controllability is designed. Considering the Bingham property of ER fluid and actuator response time, the governing equation of the ER brake is derived. And a tension propagation of wire electrode is modeled via frequency response. The tension control performance of the discharge machine is simulated by using a robust sliding mode controller.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.5
• /
• pp.1969-1975
• /
• 2012

The air brake system used in heavy vehicle is very important from the point of safety due to its weight. In general, air brake system generates relatively long response time and large loss of pressure. It is known that the response time can be decreased by optimal design of brake system, i.e., by increasing the system pressure, minimizing the air line, and material of components. In this study, We developed experimental rigs for the measurement of braking response of heavy duty trucks and compared with the simulated results obtained from the net work fluid flow system analysis code (FLOWMASTER). The effect of several parameters such as, system pressure, diameter of pipe, chamber temperature on the brake response performance have been examined.

• Proceedings of the KSME Conference
• /
• 2000.04b
• /
• pp.593-598
• /
• 2000

Experimental study is conducted to clarify the pneumatic characteristics of brake system for freight train. Empty-load and diaphragm brake systems are mainly installed in the freight trains owned by KNR(Korean National Railroad). Experimental train set is composed of sixteen freight train and one diesel locomotive that are now in use. From the experimental results, in case of commercial brake, empty-load brake system responds to the brake command more slowly than the diaphragm brake system. But, in case of release command, the response time of diaphragm brake system is shorter than that of empty-load one. In the emergency brake test, the decreasing rate of brake pipe pressure of tenth car is almost same that of decreasing rate of commercial brake service.

• Journal of the Ergonomics Society of Korea
• /
• v.30 no.3
• /
• pp.403-408
• /
• 2011

The purpose of this study was to investigate the effects of the secondary tasks such as sending text message(STM) and searching navigation(SN) on vehicle speed and distance during driving and brake response time during unexpected situation using a driving simulator. The participants included 19 college students; 9 males aged $25.2{\pm}1.0$ with $2.4{\pm}2.0years$ of driving experiences and 10 females aged $21.4{\pm}0.5$ with $1.3{\pm}0.5years$ of driving experiences. All subjects were instructed to keep a certain distance(30m) from the car ahead and a constant speed(100km/h). Average speed and average following distance were measured during 10 seconds before unexpected situation. Also, brake response time after unexpected situation was measured. Average speed was more decreased and average following distance was more increased during the driving with secondary tasks than driving only. Male maintained the assigned speed and distance better than female. The brake response time was faster during driving only than the driving with secondary tasks. And the brake response time of male was shorter than that of female.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.11
• /
• pp.171-178
• /
• 2004

This paper presents vibration characteristics of a wire cut discharge machine in which an electro-rheological brake actuator is used to control the wire tension. The ER brake actuator has several advantages including design simplicity, fast response time and real-time controllability. On the basis of the tension level required in the machine an appropriate size of the ER brake actuator is devised. The ER brake actuator is then incorporated with the machine and the field-dependent wire tension is experimentally evaluated. The straightness of the workpiece is also empirically investigated by changing the intensity of the electric field.

• The Journal of Korean Physical Therapy
• /
• v.23 no.1
• /
• pp.7-11
• /
• 2011

Purpose: Driving is essential to maintain independent living status in modern times. Many patients want to know when they can drive again, but it's only possible if they have the ability to control lower extremity muscles. In this study, we compared the effects of velocity on onset time of lower extremity muscles during driving tasks. Methods: Twelve participants (5 male, 7 female) were enrolled. EMGs were used to test the onset time of lower extremity muscles; tibialis anterior, soleus, rectus femoris. To analyze the data, we used two way ANOVA. Results: According to brake pedaling velocity, there was a significant difference in brake response time (p<0.05). Further, when comparing the lower extremity muscles, there was a significant difference in onset time (p<0.05). The order of muscle recruitment was tibialis anterior, rectus femoris, and soleus for achieving maximal velocity, but the order was rectus femoris, tibialis anterior, soleus for achieving submaximal velocity. Conclusion: Brake pedaling velocity has significant effects on onset time of muscle contractions in the lower extremities. We suggested that a future study needs more subjects and more detailed research such as evaluat-ions of visuo-motor coordination and fine motor dexterity.