• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.110-117
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• 2006

This paper presents the acceleration optimization of a high-speed LCD (Liquid Crystal Display) transfer system for the minimization of vibration. To reduce vibration is one of key requirements for the dynamic control of a high-speed LCD transfer system. In this paper, the concept of finite jerk (the first derivative of acceleration) has been introduced for realizing input acceleration. The profile of finite jerk has been optimized using a genetic algorithm so that vibration effect can be minimized. In order to incorporate a genetic algorithm, the dynamic model of a LCD transfer system which is realized by using the ADAMS software has been linked to the simulation system constructed by the MATLAB. The simulation results illustrated that the duration of finite jerk can be optimized so as to minimize the magnitude of vibration. It has been also shown that the acceleration optimization with finite jerk can make the high-speed motion of a LCD transfer system result in low vibration, compared with the conventional motion control with trapezoidal velocity profile.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.10
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• pp.1110-1118
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• 2012

In this study, for reducing the residual vibration in high speed motion control stage, an improved 5th order polynomial motion profile was developed. When a stage is moving, the current through the motor coils has the same profile of input motion profile of acceleration, therefore the characteristics of the acceleration input profile directly affect on the performance of the amplifier that includes the current control loop. Commonly low cost amplifier and motor has a narrow current control bandwidth, therefore the proposed algorithm was designed based on this practical constraint. Simulation and experimental results showed that the proposed algorithm clearly has low residual vibration characteristics than conventional 5th order polynomial motion profile on the same drive condition.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.7
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• pp.857-864
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• 2004

In this paper, a new speed pattern generation method is proposed to offer various speed patterns for the traffic changers, with the comfortable driving and the rapid transportation speed that are two important factors to determine elevator speed pattern. To reduce the speed shift impulse, acceleration and deceleration times are appropriately adjusted to the elevator system when start and stop. In order to improve transportation capability, the jerk is also adjusted to the traffic change. Using fuzzy inference system with 2 input variables and 1 output, the elevator system controls precisely, with the proposed speed pattern.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.12
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• pp.995-1006
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• 1989

If robots have the ability to track the parts on a moving conveyor belt, the efficiency of the manipulation tasks will be increased. This paper presents a motion planning algorithm for conveyor tracking. Tracking trajectory of a robot manipulator is determined by belt speed, initial part position, and initial robot position. Torque limit, maximum velocity, maximum acceleration and maximum jerk are also taken into account. To obtain the tracking solution, the problem is converted to the linear quadratic tracking problem. We describe the manipulator dynamics as second order state equation using parametric functions. Constraints on torques and smoothness are converted to those on input and state variables. The solution of the state equation which minimizes the performance index is obtained by dynamic programming method. Numerical examples are then presented to demonstrate the utility of the motion planning method developed.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1685-1690
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• 2010

This paper describes the calculation and application of the speed profile for the train speed control when the train is operated by ATO(Automatic Train Operation). We propose a speed profile calculation method considering the speed limitation and the jerk limitation, in order to maintain the quality of the train automatic operation. In previous works, ATO calculates a desired speed profile along the time, and controls the train to follow the profile. In this case, it may be hard to follow the restrictive speed along the location or to stop the train with a low location error, because of the difference between the desired location at each time and the real location of the train due to the control error. In the proposed method in this paper, we calculate a desired speed profile along the time considering the speed and jerk limitation first, and derive a speed profile along the location using it. If the restrictive speed profile is changed or the train speed strayed from the speed profile, ATO system calculates new speed profile and applies it immediately. Because ATO system controls the train speed based on the train location, the accuracy of the train location control can be improved. A simulation system for the test of the automatic train operation using this method is designed.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.401-407
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• 2012

This paper analyzes performance of major obstacle avoidance methods. For the analysis, numerical performance indexes are proposed: motion distance to goal point, motion time, distance to obstacles, and smoothness of the motion. Especially, the index of smoothness measures efficiency of the motion using the angular acceleration and jerk of the robot heading. Four major obstacle avoidance methods are compared in terms of the performance indexes. The four methods are artificial potential field(APF) method, elastic force(EF) method, APF with virtual distance, and EF with virtual distance. Through simulation, the four methods are compared and features of the methods are explored.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.151-157
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• 2006

The passenger car drivers want in general to feel good driveability, but they sometimes feel uncomfortable by shock and jerk phenomena when they push or release acceleration pedal with clutch on state. In this paper, the shock and jerk characteristics are studied on the vehicles controlled by the throttle-by-wire system. Experiments and simulations were carried out on two vehicles which show different control characteristics. The engine torque control characteristics was analyzed by measuring cylinder pressure. Various specification factors of the vehicles and the torque control logic of the engines were simulated through experimental data basis. The result shows the spring effect of the trans-axle in the drive-train is one of the most important factors of the shock-jerk phenomena and the engine torque control method is also responsible for the reducing the shock-jerk amplitude. In this paper a new control logic of the engine torque is suggested for the better driveablility on the tip-in/out event.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.457-458
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• 2006

A method for obtaining smooth, jerk bounded feed rate profile in high speed machining has been developed. This study proposes a NURBS interpolator based on adaptive feed rate control with a well developed look ahead algorithm which takes into account the machining dynamics as well. Limitation of jerk and proportional torque rate result in smoothened loads on the machine which effectively reduces excitation of the resonant frequencies of the machine. It is found that the values of the feed rate of the down stream sharp corner have profound effect on the feed rate of the upstream sharp corners. By using a windowing scheme the feed rate profile obtained after look ahead method is re-interpolated to reduce the jerk related problems. This is compared with the adaptive NURBS interpolator to show the effectiveness of the proposed method. Simulation results indicate that the consideration of 'ripple effect' is important in avoiding jerk and thereby increasing the machining accuracy.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.113-119
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• 2005

The passenger car drivers want in general to feel good driveability, but they sometimes feel uncomfortable by shock and jerk phenomenon when they push or release acceleration pedal with clutch engaged. In this paper, the shock and jerk characteristics are studied on the vehicles of the throttle-by-wire system. With this system, the throttle is not directly controlled by drivers but via a microprocessor. So the control logic of the throttle is very important on tip-in and tip-out driveability. Experiments were carried out on two vehicles which show different control characteristics. The torque control logics were analyzed by measuring cylinder pressures. The results show that special torque control logic is needed at tip-in/out state for good driveability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3573-3578
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• 2015

Transition curves are located between curve and straight section in railway. These transition curves are vulnerable to the ride comfort of passengers and safety of a vehicle because lateral acceleration, lateral jerk and roll velocity increase as curvature and cant change along the transition curves. In this paper, ride comfort on the transition curve was calculated on the basis of lateral acceleration and roll velocity measurements. The evaluation of ride comfort was conducted according to the methodology specified in European Standard. The distribution characteristics of the comfort index were investigated for the korean conventional line from the evaluation results. The influence of the curve radius and the vehicle speed on the ride comfort index was also investigated. Finally, the relationship between ride comfort and the rate of cant changes on transition curves was analyzed.