• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.7
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• pp.329-334
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• 2005

This paper presents the optimal design for reducing the rotor inertia in order to improve the driving characteristic of BLDC motor for robots. The parallel Genetic Algorithm is performed to rotor inertia minimization in optimal design. Also, velocity profile with finite jerk method is introduced to reduce vibration of BLDC motor. As a result, a torque characteristic is same although rotor inertia is reduced to 2/3 compared with prototype model. And, maximum vibration value is reduced by 63.4[$\%$] according to the application of finite .jerk method.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.8
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• pp.351-357
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• 2005

This paper presents vibration minimization of a PMLSM driven feed-slide by using optimized smooth velocity curve with finite jerk. First of all, the PMLSM was designed and made to reduce detent force. Next, a PMLSM driven feed-slide system was mathematically modeled as a 4-degree-of-freedom lumped parameter model. The key idea of our vibration minimization method is to find out the most appropriate smooth velocity(feedrate) curve with finite jerk. The validity of our proposed method has been verified by comparing computer simulation results of the feed-slide model with experimental ones.

• Journal of Computational Design and Engineering
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• v.2 no.4
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• pp.206-217
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• 2015

This paper presents a complete S-shape feed rate scheduling approach (CSFA) with confined jerk, acceleration and command feed rate for parametric tool path. For a Non-Uniform Rational B-Spline (NURBS) tool path, the critical points of the tool path where the radius of curvature reaches extreme values are found firstly. Then, the NURBS curve is split into several NURBS sub-curves or blocks by the critical points. A bidirectional scanning strategy with the limitations of chord error, normal/tangential acceleration/jerk and command feed rate is employed to make the feed rate at the junctions between different NURBS blocks continuous. To improve the efficiency of the feed rate scheduling, the NURBS block is classified into three types: short block, medium block and long block. The feed rate profile corresponding to each NURBS block is generated according to the start/end feed rates and the arc length of the block and the limitations of tangential acceleration/jerk. In addition, two compensation strategies are proposed to make the feed rate more continuous and the arc increment more precise. Once the feed rate profile is determined, a second-order Taylor's expansion interpolation method is applied to generate the position commands. Finally, experiments with two free-form NURBS curves are conducted to verify the applicability and accuracy of the proposed method.

• 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.

• Proceedings of the KIEE Conference
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• summer
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• pp.935-937
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• 2004

This paper is proposed vibration minimize method of slotted PMLSM which is designed to minimize detent force. For improvement of operational performance by changing velocity profile to reducing the vibration at discontinuous section of acceleration curve in this paper, proter type machine is made, the vibration is compared general trapezoid velocity profile with vibration minimization velocity profile.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.12
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• pp.1079-1085
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• 2012

For precise motion control, S-curve velocity profile is generally used but it has disadvantage of relatively long calculation time for floating-point arithmetics. In this paper, we present a new generating method for velocity profile to reduce delay time of profile generation so that it overcomes such disadvantage and enhances the efficiency of precise motion control. In this approach, the velocity profile is designed based on the gamma correction expression that is generally used in image processing to obtain a smoother movement without any critical jerk. The proposed velocity profile is designed to support both T-curve and S-curve velocity profile. It can generate precise profile by adding an offset to the velocity profile with decimals under floating point that are not counted during gamma correction arithmetic operation. As a result, the operation time is saved and the efficiency is improved. The proposed method is compared with the existing method that generates velocity profile using ring buffer on a 8-bit low-cost MCU. The result shows that the proposed method has no delay in generating driving profile with good accuracy of each cycle velocity. The significance of the proposed method lies in reduction of the operation time without degrading the motion accuracy. Generated driving signal also shows to verify effectiveness of the proposed method.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.609-615
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• 2012

TPS (Train Performance Simulation) based on ATO (Automatic Train Operation) is required for driverless LRT (Light Rail Transit) operation plan instead of typical TPS based on driver operation. In this paper, new TPS model using ATO pattern is proposed and compared with the automatic train operation result in a test line of Seoul Metro Line 6 and in a whole line of Busan-Gimhae LRT. The actual ATO pattern can be very accurately simulated by new TPS model with the introduction of 4 parameters such as commercial braking rate, jerk, station stop profile and grade converted distance. The commercial scheduled time for driverless automatic train operation can be proposed to have "Fast" mode TPS trip time plus 3 seconds/km margin recommended by Korean standard LRT specification in this paper.

• Transactions of the Society of Information Storage Systems
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• v.1 no.1
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• pp.99-107
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• 2005

According to recent trend, hard disk drive(HDD) has been smaller and less weight. Therefore, it needs new method of writing position information. In this thesis, a new controller that is suitable for SSW is proposed. The controller accepted SSW technology that is used to write position information in current HDD industry. The important condition to perform SSW is to reach constant velocity decided from the head velocity profile as fast as possible. The constant velocity decides the positional accuracy of spiral pattern and setup time decides the capacity of HDD. The head velocity profile as a reference signal must be designed not to cause resonance mode. The proposed controller was designed with consideration of these 3 elements, and it properly works for SSW. The velocity profile designed with SMART control not only minimizes the jerk, but also does not cause the resonance mode of a plant. After designing a conventional PID controller, it compared with electrical spring technique and ZPET technique.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.3
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• pp.221-233
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• 2007

In this paper, a simple but effective position profile generation algorithm for single axis high dynamic linear machine drive system is presented. In the recent industrial application fields like as LCD/PDP and semiconductor factory, requirements for the high performance positioning system with optimal position profile generator are highly increased to reduce the overall processing time. There might be various solutions for position profile generating algorithm according to the application type. A square-wave Impact quantity(Jerk) based algorithm with minimal locomotion time is argued in this paper to minimize the total time of one movement under some specific constrains such as maximum speed limit and maximum acceleration limit. In order to reduce the calculation efforts and satisfy the minimal locomotion time condition, the time variants representing each profile sector and a simple condition comparison algorithm are adopted. Also, the actual implementation method for profile generation algorithm and it's real performance results are presented through commercial linear machine drive system.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1028-1032
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• 2004

In order to prevent machine tool feed slide system from transient vibrations during operations, machine tool designers usually adopt some typical design solutions; box-in-box typed feed slides, optimizing moving body for minimum weight and dynamic compliance, and so on. Despite all efforts for optimizing design, a feed drive system may experience severe transient vibrations during high-speed operation if its feed rate control is unsuitable. A rough feed rate curve having discontinuity in its acceleration profile causes a serious vibration problem in the feed slides system. This paper presents a feed rate optimization of a ball screw driven machine tool feed slide system for its minimum vibration. Firstly, a ball screw feed drive system was mathematically modeled as a 6-degree-of-freedom lumped parameter system. Next, a feed rate optimization of the system was carried out for minimum vibrations. The main idea of the feed rate optimization is to find out the most appropriate smooth acceleration profile with jerk continuity. A genetic algorithm was used in this feed rate optimization