• 제어로봇시스템학회논문지
• /
• 제8권2호
• /
• pp.104-112
• /
• 2002

Controllers for acoustic noise reduction in disk drives have been developed but they have slower seek time performance than time-optimal controllers. We propose a new seek servo controller that has acoustic noise reduction benefit and faster seek time performance than conventional controllers. The proposed controller is designed to make sure that head is moved with maximized acceleration and deceleration under the voltage limitation imposed on head-positioning motor and so it provides faster seek time than conventional controllers designed by considering the current limitation. The experimental results using a commercially available disk drive confirm that the use of the proposed controller results in foster seek time than conventional controllers for acoustic noise reduction.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 추계학술대회논문집
• /
• pp.401-405
• /
• 2003

Sound quality is becoming a major concern in optical disc drives (ODD). In order to improve the sound quality of slim type ODDs, we changed lead screw pitch and firmware algorithm in the seek mode. To evaluate the sound quality, the PCM (Paired Comparison Method) was adopted and the result was compared with the time-averaged loudness spectrum. Sound signals were also recorded and modified by increasing or decreasing selected frequency bands to verify their sensitivities to the sound quality. As a result of jury test, preferred frequency bands are associated with the time-averaged loudness spectrum.

• 한국음향학회지
• /
• 제14권4호
• /
• pp.5-11
• /
• 1995

본 논문에서는 광디스크 드라이브가 디스크상의 데이터를 탐색하는데 소요되는 평균탐색 시간 (Average Seek Time)을 개선하기 위한 방법으로 트랙추적 기준신호 (ref_T. E)와 샘플펄스 신호를 사용하여 평균탐색시간을 줄일수 있는 새로운 알고리즘을 제안 하였다. ref_T. E신호와 샘플펄스 신호를 사용하여 트랙을 탐색할 경우 목적트랙으로 이동한 다음 다시 위치를 확인하고 보상할 필요가 없도록하여 평균탐색시간을 개선하였다. 실험결과 28sec의 평균탐색시간을 보였다.

• 제어로봇시스템학회논문지
• /
• 제8권7호
• /
• pp.539-546
• /
• 2002

This paper presents a new direct seek control scheme that provides fast data access capability and robust performance for high-speed rotational optical disk drives (ODD). When a disk is rotating at a high speed to obtain fast data transfer in ODD, the magnitude and frequency of velocity disturbance caused by eccentric rotation of the disk increase in proportion to the rotational speed of the disk. Such disturbances make it almost impossible for the conventional seek control scheme to achieve stable and satisfactory seek performance. We analyze the problems that may arise when the conventional seek control scheme is applied to the high-speed rotational ODD and propose a new direct seek control scheme that will solve such problems. In the proposed scheme, a seek control system is designed such that its performance is guaranteed for a set of plants with parameter perturbations. The performance of the proposed seek control scheme is shown by experiments using a high-speed rotational ODD.

• Transactions on Control, Automation and Systems Engineering
• /
• 제3권3호
• /
• pp.146-151
• /
• 2001

Optical disk drive has excellent advantage of random accessibility of which performance is measured by access time. However, due to the increased rotational velocity of the disk and constraints of mechanical structure, two-stage seek algorithm which executes coarse and fine seeks sequentially has been adopted in most commercial optical disk drives. Although the laser spot is moved to a target track by a single seek operation, the limited operation range of the fine actuator restricts the application of the fine seek algorithm below a few hundreds of tracks. Especially, excessive movement of the objective lens causes a failure in generation of track-cross pulse and results in an unstable seek operation. In this paper, a new control algorithm for extending the fine seek range is proposed with an appropriate control structure. The coarse actuator is utilized to reduce the misalignment between the objective lens and the laser beam axis, and the fine actuator is controlled to follow the reference velocity trajectory. The proposed algorithm is applied to a CD-ROM drive to show its feasibility and some experimental results are presented.

• 한국소음진동공학회논문집
• /
• 제13권11호
• /
• pp.860-867
• /
• 2003

This paper presents a systematic method measuring a velocity disturbance to design the robust seek loop system of optical disk drives. The velocity disturbance caused by the rotation of a disk has a greater influence on the performance of the seek control loop as the rotational speed increases. Thus, it needs to measure the extent of the velocity disturbance and design the seek control loop based on the measured data. The measurement method of the velocity disturbance is a real-time . method using a measurable velocity and a velocity controller output and is a robust method considering actuator uncertainties. The loop gain adjustment algorithm is introduced to compensate for the actuator uncertainties. The proposed method is implemented by an experimental digital system and is evaluated through an experiment.

• 가족자원경영과 정책
• /
• 제19권2호
• /
• pp.127-148
• /
• 2015

This study compared types of time and money attitudes by respondents' characteristics, and compared leisure consumption behavior and leisure satisfaction among different groups, which are classified by attitudes toward time and money. It also verified a structural model for the relationship of leisure satisfaction and the attitudes toward time and money, and investigated the moderating effects of leisure consumption behavior. Data were obtained from a questionnaire completed by 512 adult consumers. Using factor analyses and cluster analyses, this study classified the types of time and money attitudes. The time attitude was categorized according to four clusters: time-insensibility, future- oriented, present-oriented, and past-oriented. The money attitude was divided into four clusters: future safety, stinginess/anxiety, diversion, and power/prestige. The major findings of this study were as follows: First, the propensity of leisure consumption behavior to seek fashion and conspicuousness was higher for time-insensibility group than for the others. However, the propensity of rational consumption behavior for leisure was higher for the future-oriented group. The level of leisure satisfaction was the highest for the time-insensibility group. Second, the propensity of leisure consumption behavior to seek fashion and conspicuousness was higher for those who considered money as tools for diversion and power/prestige. The propensity of rational consumption behavior for leisure was higher for the future safety and stinginess/anxiety groups. The level of leisure satisfaction was significantly higher for the diversion group. Third, from the results of structural analyses, the time-insensibility attitude showed a positive effect on the leisure consumption behavior to seek fashion and conspicuousness. The future-oriented attitude had a positive effect on the propensity of rational consumption behavior for leisure. The money attitudes of diversion and power/prestige had positive impacts on the leisure consumption behavior to seek fashion and conspicuousness, although they had negative effects on the propensity of rational consumption behavior for leisure. The leisure consumption behavior to seek fashion and conspicuousness had a positive effect on leisure satisfaction, although the rational consumption behavior for leisure had a negative effect.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
• /
• pp.391-394
• /
• 1996

The effects of time-sampling on nonlinear output regulation problem is investigated. Output regulatedness is preserved under time sampling as in linear systems, however output regulatability is not robust with respect to time-sampling, and thus one needs to seek an approximate nonlinear sampled-data output regulator.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
• /
• pp.83-85
• /
• 1994

This paper describes the dual mode control of the LDM(Linear DC motor) for carrier. The dual mode control consists of seek and analogue control. In seek mode, LDM is moved in the shortest time by switching line, and in analogue mode keeps at origion with high accuracy. We proposed different switching line method according to driving direction.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 II
• /
• pp.977-982
• /
• 2001

In this paper, we deal with the analysis and optimum design of a disc drive feeding system. Using this proposed design method, we can determine an optimal step motor and lead-screw for the shorter seek time and required seek resolution. Simulation results show that this method can be potentially implemented in the design of a feeding system.