Fast seek control for flexible disk drive systems with back EMF and inductance

Abstract

This paper derives shaped time-optimal servomechanism (STOS) controllers for flexible disk drive systems considering the effect of back electromotive force (back EMF) and coil inductance. To eliminate the vibration due to an unwanted flexible mode, input shaping is used to alter the time-optimal velocity phase-plane profile that moves the third-order nonflexible dynamics from rest to rest. Because the closed-form solution for the time-optimal control of the third-order nonflexible dynamics is not known, the shaped time-optimal velocity phase-plane profiles are derived numerically. By using a curve-fit polynomial to approximate these shaped timeoptimal velocity phase-plane profiles, we obtain an analytical expression for the STOS control. Simulations show that the curve-fit polynomials give high accuracy and the STOS control yields near time-optimal performance without unwanted residual vibration.

Intelligent Backstepping System to Increase Input Shaping Performance in Suppressing Residual Vibration of a Flexible-Joint Robot Manipulator

“…Singer and Seering in [7] extended the Posicast control by increasing its robustness to parameter uncertainty and patented the technique under the name input shaping. Applications of the input shaping technique range from gantry crane (Sorensen et al in [8]), bridge crane (Peng et al in [9]), tower crane (Huey et al in [10]), boom crane (Huang et al in [11]), flexible-link robot (Chatlatanagulchai et al in [12]), flexible-joint robot (Chatlatanagulchai and Saeheng in [13]), liquid sloshing in container (Baozeng and Lemei in [14]), flexible spacecraft (Zhang and Zhang in [15]), coordinate measuring machine (Singhose et al in [16]), cam follower (Pridgen and Singhose in [17]), telescopic handler (Park and Chang in [18]), cherry picker (Hongxia et al in [19]), dual solenoid actuator (Yu and Chang in [20]), MEMS contact switch (Do et al in [21]), hard disk drive (La-orpacharapan and Pao in [22]), cable-driven crane (Huey and Singhose in [23]), high-rise elevator (Fortgang et al in [24]), wave suppression (Yang and Liang in [25]), atomic force microscopy (Schitter et al in [26]), CNC machine tool (Altintas and Khoshdarregi in [27]), micro-milling machine (Fortgang and Singhose in [28]), wafer stage in chip manufacturing (Roover and Sperling in [29]), automated highway (Bae and Gerdes in [30]), brushless motor (Chang et al in [31]), cooperative motion between two robots (Zhang et al in [32]), twin rotor (Toha and Tokhi in [33]), quadrotor with sling load (...…”

Shaped time-optimal control for disk drive systems with back EMF, slew rate limits, and different acceleration and deceleration rates

“…However, as discussed in [6][7][8][9], in practice, overshoot may occur due to implementation issues or disturbances. Thus we assign control values to these regions (see Fig.…”

“…We recently developed a shaped time-optimal servomechanism (STOS) control technique based on shaping timeoptimal phase-plane trajectories [6][7][8][9]. A block diagram of a closed-loop system with a STOS controller is shown in Fig.…”

“…The closed-form solutions of the time-optimal control for the second-order rigid body with damping system with different acceleration and deceleration capabilities and for the thirdorder rigid body system as described in [9] are not known. The time-optimal controls must be solved numerically.…”

“…The time-optimal controls must be solved numerically. However, we still can derive the STOS control analytically by using the curve-fit approximation of the switching time of the timeoptimal control for the system having the second-order rigid body with damping and the curve-fit approximations of the switching curves for the system having the third-order rigid body [9]. This paper is organized as follows.…”