Method for overcoming a stiction condition in disk drive

A method for overcoming a stiction condition in a disk drive, said method comprising:

• providing a plurality of disks each having a pair of disk surfaces, each of the disk surfaces having a corresponding actuator arm assembly including a head;
• providing a spin motor for rotating said plurality of disks when a stiction condition does not exist;
• providing a voice coil motor for positioning said heads relative to said disk surfaces when a stiction condition does not exist;
• providing a microprocessor for controlling application of a voice coil motor current to said voice coil motor and for controlling application of a spin motor current to said spin motor;
• applying a spin motor current to said spin motor;
• sensing that the spin motor is not rotating said plurality of disks and, hence, a stiction condition exists;
• applying a first oscillating current to said voice coil motor in response to said stiction condition, said first oscillating current having a fixed frequency and a first amplitude;
• determining whether said spin motor is rotating in response to said first oscillating current;
• and,
• continuing to apply said first oscillating current for at least one commutation state of said spin motor after determining that said spin motor is rotating in response to said first oscillating current.

A method for overcoming a stiction condition in a disk drive, said method comprising:

• providing a plurality of disks each having a pair of disk surfaces, each of the disk surfaces having a corresponding actuator arm assembly including a head;
• providing a spin motor for rotating said plurality of disks when a stiction condition does not exist;
• providing a voice coil motor for positioning said heads relative to said disk surfaces when a stiction condition does not exist;
• providing a microprocessor having firmware for controlling application of a voice coil motor current to said voice coil motor and for controlling application of a spin motor current to said spin motor;
• applying a spin motor current to said spin motor;
• sensing that the spin motor is not rotating said plurality of disks and, hence, a stiction condition exists;
• applying a first oscillating current to said voice coil motor in response to said stiction condition, said first oscillating current having a frequency and an amplitude, wherein said frequency is determined by said firmware, wherein said firmware is supplied with information relating to the number of heads in the drive, and wherein said firmware determines said frequency based upon a square-root dependence of the drive's lateral resonance on the number of heads.

A method for overcoming a stiction condition in a disk drive, said method comprising:

• providing a plurality of disks each having a pair of disk surfaces, each of the disk surfaces having a corresponding actuator arm assembly including a head;
• providing a spin motor for rotating said plurality of disks when a stiction condition does not exist;
• providing a voice coil motor for positioning said heads relative to said disk surfaces when a stiction condition does not exist;
• providing a microprocessor for controlling application of a voice coil motor current to said voice coil motor and for controlling application of a spin motor current to said spin motor;
• applying a spin motor current to said spin motor;
• sensing that the spin motor is not rotating said plurality of disks and, hence, a stiction condition exists;
• applying a first oscillating current to said voice coil motor in response to said stiction condition, said first oscillating current having a fixed frequency and a first amplitude;
• determining whether said spin motor is rotating in response to said first oscillating current;
• applying a second oscillating current to said voice coil motor after determining that said spin motor is not rotating, said second oscillating current having a second amplitude and a frequency equal to said fixed frequency, said second amplitude being greater than said first amplitude;
• determining whether said spin motor is rotating in response to said second oscillating current;
• and,
• continuing to apply said second oscillating current for at least one commutation state of said spin motor after determining that said spin motor is rotating in response to said second oscillating current.

A method for overcoming a stiction condition in a disk drive, said method comprising:

• providing a plurality of disks each having a pair of disk surfaces, each of the disk surfaces having a corresponding actuator arm assembly including a head;
• providing a spin motor for rotating said plurality of disks when a stiction condition does not exist;
• providing a voice coil motor for positioning said heads relative to said disk surfaces when a stiction condition does not exist;
• providing a microprocessor for controlling application of a voice coil motor current to said voice coil motor and for controlling application of a spin motor current to said spin motor;
• applying a spin motor current to said spin motor;
• sensing that the spin motor is not rotating said plurality of disks and, hence, a stiction condition exists;
• applying a first oscillating current to said voice coil motor in response to said stiction condition, said first oscillating current having a fixed frequency and a first amplitude;
• determining whether said spin motor is rotating in response to said first oscillating current;
• applying a second oscillating current to said voice coil motor after determining that said spin motor is not rotating, said second oscillating current having a second amplitude and a frequency equal to said fixed frequency, said second amplitude being greater than said first amplitude;
• determining whether said spin motor is rotating in response to said second oscillating current;
• applying a third oscillating current to said voice coil motor after determining that said spin motor is not rotating, said third oscillating current having a third amplitude and a frequency equal to said fixed frequency, said third amplitude being greater than said second amplitude;
• determining whether said spin motor is rotating in response to said third oscillating current;
• and,
• continuing to apply said third oscillating current for at least one commutation state of said spin motor after determining that said spin motor is rotating in response to said third oscillating current.