Micropositioning device for disk head testing system

A micropositioner for positioning a stage along a first dimension relative to a reference position, in response to a command signal indicating a desired displacement amount, comprising:

• a positioning mechanism having a stage, said positioning mechanism translating said stage by an actual displacement amount relative to said reference position in said first dimension;
• first and second electrical plates both mounted fixedly in said first dimension relative to one of said reference position and said stage and opposing each other so as to create an electrical field having a component in said first dimension between said first and second plates when a voltage difference is applied across said first and second plates;
• an electrical probe mounted fixedly relative to the other of said reference position and said stage, between said first and second plates and in said electrical field, said probe sensing a probe voltage in said electrical field;
• and
• a closed loop control circuit coupled to said first and second plates, to said probe and to said positioning mechanism, said closed loop control circuit controlling said positioning mechanism to translate said stage in said first dimension until said probe voltage indicates that said actual displacement amount matches the desired displacement amount indicated by said command signal.

A micropositioner for positioning a disk drive head at a desired radial position of a disk on a spindle, in response to a coarse positioning command signal and a fine positioning command signal, comprising:

• a coarse positioner having a first stage, said coarse positioner translating said first stage by a first displacement amount relative to said spindle in a first dimension in response to said coarse positioning command signal;
• a parallelogram flexure having first and second opposite sides and further having third and fourth opposite sides, said first side being mounted fixedly in said first dimension relative to said first stage and one of said second, third and fourth sides supporting said disk drive head;
• a piezoelectric translator having a first piezoelectric mounting point mounted fixedly in said first dimension relative to said first stage and further having a second piezoelectric mounting point mounted fixedly in said first dimension relative to a particular one of said second, third and fourth sides of said parallelogram flexure, said piezoelectric translator having a control input and controlling extension of said second piezoelectric mounting point relative to said first piezoelectric mounting point in said first dimension in response to a signal at said control input;
• a fine displacement sensor which senses a fine displacement amount being displacement of said disk drive head relative to said first stage in said first dimension;
• and
• a fine positioning feedback loop coupled to said piezoelectric translator control input and to said fine displacement sensor and controlling said piezoelectric translator to extend said second piezoelectric mounting point relative to said first piezoelectric mounting point in said first dimension in response to a difference between a fine displacement indicated by said fine displacement sensor and a desired fine displacement indicated by said fine command signal.