High-order nonsingular terminal slip mode control method for two-stage magnetic head positioning system

Abstract

The invention discloses a high-order nonsingular terminal slip mode control method applied to a two-stage magnetic head positioning system of a hard drive. The method comprises the following steps of: establishing a kinetic model of a flexible access arm system under the consideration of a flexible mode and the uncertainty of model parameters; and putting forward a three-order nonsingular terminal slip mode control method for permodeing one-time low-pass filtration on a control signal to effectively weaken the phenomenon of buffeting. In the method, a Lagrange method and an assumed mode method are used for deriving a dynamical equation of a flexible access arm two-stage system, and an output redefinition method is adopted for decomposing the flexible two-stage system into an input-output subsystem and an internal subsystem. Specific to the input-output subsystem in combination with two-order nonsingular terminal slip mode control and linear slip mode control, a three-order nonsingular terminal slip mode controller is designed, the converging characteristic of the system within limited time is proved through a Lyapunov stability theory, and the effectiveness of the method is verified by emulating with Matlab/Simulink software.

Description

technical field [0001] The invention belongs to the field of control engineering, in particular to a high-order non-singular terminal sliding mode control method for a flexible two-stage magnetic head positioning system of a hard disk drive, which is used to realize high-speed and high-precision tracking and positioning. Background technique [0002] With the continuous increase of the track density of hard disk drives, higher requirements are put forward for the speed and accuracy of the head positioning system, and the two-stage head positioning system is an effective way to achieve higher servo bandwidth and higher positioning accuracy. In this system, the first-stage voice coil motor is used as a coarse-tuning motor, which has a larger stroke range; the second-stage micro-actuator made of piezoelectric ceramic material is located between the elastic area of ​​the cantilever beam and the slider, which can Quickly achieve high-precision positioning of the magnetic head. T...

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Problems solved by technology

This type of method takes into account the coupling between the two-stage actuators, but the order of the controller is relatively high

At the same time H ∞ The control method adopts H ∞ Norm to characterize, only the worst case is considered, making the robustness conservative, and the Riccati equation used in the controller design only has a theoretical solution, so the system will have a certain error

[0005] At the same time, the above two types of existing methods regard the system as a rigid model to design the controller, without considering the influence of the flexible mode of the access arm on the system, HLi, C Du, Y Wang. In "IEEE / ASME Transactions Transactions on Mechatronics", the research results in the paper "Optimal Reset Control for a Dual-Stage Actuator System in HDDs" published in the 16th issue of March 2011 show that when a rigid model is used as the controlled object, although the simulation results show that it can track well Seek, but there will be a lot of vibration in the experimental test

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