University of Twente Student Theses


Dual stage actuation in linear drive systems

Jong, Gerdo (2005) Dual stage actuation in linear drive systems.

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Abstract:The aim of this research was to contribute to the transfer of knowledge and experience of research in HDD dual-stage actuation to dual-stage actuation in linear drive systems. As a case study, application of dual-stage actuation to the Fast Component Mounter (FCM) is considered. Dual-stage actuation is the combination of a first-stage actuator, which has a relative large stroke and small bandwidth, with a second-stage actuator, which has a relative small stroke and large bandwidth. The combination of these two actuators can result in a larger bandwidth, compared to using only the first-stage actuator. In literature, it is reported that the principle of dual-stage actuation is applied to increase the bandwidth of HDDs. As a result, the response time of positioning the read/write head can be decreased and at the same time, the accuracy of positioning the read/write head can be increased. In applying dual-stage actuation to HDDs, decoupled operation of the two actuators is assumed. Consequently, it is shown that two controllers for each of the actuators can be independently designed using SISO-design methodologies. During this research, the topic of decoupling has been investigated. It has been shown that decoupling occurs only if the load mass to the second-stage actuator is very small. Hence, the SISO-design methodologies from literature cannot be applied directly to the coupled system. In that case, the dual-stage actuated system becomes unstable. Therefore, a tuning procedure is presented to tune the controller parameters of the decoupled designed controllers, such that the coupled system is stabilized. Furthermore, attention is paid to the sensory system, which is required for effective dual-stage operation. Since in HDDs the position of the read/write head is measured, the sensory system need not be adapted for effectively including a second-stage actuator. However, in case of the FCM, the position of the end-effector is not measured. For both the coupled and decoupled model it is investigated which changes to the sensory system should be made, in order to increase the bandwidth of the dual-stage actuated FCM. Finally, for both models, it was shown how much the sensitivity bandwidth and the closed-loop bandwidth can be increased by including a piezo-actuator as second-stage actuator. In this analysis, also the load mass to the second-stage actuator is varied, in order to evaluate the achievable bandwidth.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:53 electrotechnology
Programme:Electrical Engineering MSc (60353)
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