Disk drive with mode canceling actuator
AssigneeHitachi Global Storage Technologies Netherlands B.V.
InventorsFu-Ying Huang, Wayne Isami Imaino, Jiann-Chang Lo, Matthew T. White
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Abstract
A disk drive having an arm assembly equipped with a primary actuator such as a VCM and a mode-canceling actuator such as a PZT mounted at a location selected in such a way that the strain in the mode-canceling actuator is in phase with sway deformations of the primary actuator produced by the vibrational modes of the arm assembly. The primary actuator is driven to exert a primary force, f ⋁ pm , on the arm assembly while the secondary driver ensures that the mode-canceling actuator applies a mode-canceling force, f ⋁ m c , on arm assembly such that the gain and phase of one or more vibrational modes are canceled.
Claims14
An actuator system deployed in a disk drive wherein said disk drive has a rigid arm assembly experiencing a plurality of vibrational modes including predetermined vibrational modes, said actuator system comprising:
- a primary actuator mounted on said rigid arm assembly at a first location;
- at least one mode-canceling actuator attached to said rigid arm assembly at a selective location wherein said selective location is determined by empirical or analytic techniques such that the strain in said at least one mode-canceling actuator is in phase with sway deformations of said primary actuator produced by said vibrational modes;
- a primary driving means directly connected to said primary actuator for causing said primary actuator to exert a primary force, f ⋁ pm ,
- on said rigid arm assembly;
- a secondary driving means directly connects to said primary driving means and to said at least one mode-canceling actuator for causing said at least one mode-canceling actuator to exert a mode-canceling force, f ⋁ m c ,
- on said rigid arm assembly such that at least one of said vibrational modes is canceled while preserving rigid body motion characteristics of said rigid arm assembly;
- and
- a control means for setting a ratio r between said primary force f ⋁ pm
- and said mode-canceling force f ⋁ m c ,
- wherein the value of said ratio r and said selective location are determined such that none of said vibrational modes produced by said mode-canceling force exceeds any corresponding vibrational modes caused by said primary actuator by more than 6 dB.
A vibrational mode canceling mechanism for stabilizing a servo-controlled actuator system deployed in a disk drive having an arm assembly, wherein said vibrational mode canceling mechanism is capable of canceling amplitude and phase effects of at least one of a plurality of vibrational modes experienced by said arm assembly while minimizing the mass of said arm assembly and preserving rigid body motion characteristics of said arm assembly, and wherein said arm assembly has a primary actuator, said vibrational mode canceling mechanism comprising:
- determining, by empirical or analytic techniques an exact position for attaching onto said arm assembly a mode-canceling actuator such that the strain in said mode-canceling actuator is in phase with sway deformations of said primary actuator produced by said vibrational modes;
- generating a primary driving signal for causing said primary actuator to exert a primary force, f ⋁ pm ,
- on said arm assembly;
- in response to said primary driving signal, generating a secondary driving signal for causing said mode-canceling actuator to exert a mode-canceling force, f ⋁ m c ,
- on said arm assembly such that said at least one vibrational mode is canceled, said vibrational mode mechanism further including controlling a ratio r between said primary force f ⋁ pm
- and said mode-canceling force f ⋁ m c ,
- wherein the value of said ratio r and said exact location are determined such that none of said vibrational modes produced by said mode-canceling force exceeds any of the corresponding vibrational modes caused by said primary actuator by more than 6 dB.
Dependencies are inferred from the claim text.