Method and apparatus to analyze accessor performance

• US 6,381,517 B1
• Filed: 02/01/2001
• Issued: 04/30/2002
• Est. Priority Date: 02/01/2001
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Butka, David J., Yardy, Raymond
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Marc, McDieunel, Marc, McDieunel
• Application Number:
  US09/775,222
• Time in Patent Office: 453 Days
• Field of Search: 700/245-249, 700/251, 700/258, 700/260-261, 700/218, 360/92, 360/191, 360/30.31, 360/30.45, 360/30.46, 360/30.49, 414/273, 414/280, 414/807, 414/281, 414/753.1, 701/23, 701/14, 701/30, 713/1, 711/111-114, 711/159, 369/30.31, 901/46, 710/1
• US Class Current: 700/247
• CPC Class Codes: G11B 17/225 wherein the disks are transferred from a fixed magazine to a fixed playing unit using a moving carriage
• CPC Class Codes: G11B 17/228 Control systems for magazines G11B17/225 takes precedence

Abstract

An automated data storage system which comprises one or more robotic accessors movably disposed therein, each such accessor including a revolving memory buffer and a velocity control program, wherein the velocity control program stores operational data regarding the gripping and pivot mechanisms disposed on the accessor. A method to diagnose the cause of an accessor failure by downloading and analyzing the operational data stored on the defective accessor'"'"'s revolving memory buffer.

Claims

1. An accessor for retrieving a plurality of data storage media stored in a plurality of storage slots in an automated data storage system and for delivering that retrieved data storage media to one or a plurality of data storages for reading and/or writing data thereon, said accessor comprising:

an accessor control card having a revolving memory buffer;

a velocity control program stored on said accessor control card;

a first gripper;

a first gripper motor disposed on said first gripper;

a first gripper motor tach disposed on said first gripper motor, wherein said first gripper tach provides at a first time first gripper motor tach information to said velocity control program;

a pivot motor;

a pivot motor tach disposed on said pivot motor, wherein said pivot motor tach provides at said first time pivot motor tach information to said velocity control program;

wherein said velocity control program stores said first gripper motor tach information and said pivot motor tach information in said revolving memory buffer.

2. The accessor of claim 1, further comprising:

a second gripper;

a second gripper motor disposed on said second gripper;

a second gripper motor tach disposed on said second gripper motor, wherein said second gripper tach provides at said first time second gripper motor tach information to said velocity control program;

wherein said velocity control program stores said first gripper motor tach information, said second gripper motor tach information, and said pivot motor tach information in said revolving memory buffer.

3. The accessor of claim 2, further comprising a wireless communication device.

4. The accessor of claim 2, wherein said velocity control program determines and stores in said revolving memory buffer:

a first tach position, a first demand velocity, a first PWM voltage, and a first actual velocity using said first gripper motor tach information;

a second tach position, a second demand velocity, a second PWM voltage, and a second actual velocity using said second gripper motor tach information; and

a third tach position, a third demand velocity, a third PWM voltage, and a third actual velocity using said pivot motor tach information.

5. The accessor of claim 2, wherein said first gripper motor tach provides to said velocity control program updated first gripper motor tach information obtained at a second time, and wherein said second gripper motor tach provides to said velocity control program updated second gripper motor tach information obtained at said second time, and wherein said pivot motor tach provides to said velocity control program updated pivot motor tach information obtained at said second time, wherein the difference between said first time and said second time comprises the interrupt period.

6. The accessor of claim 5, wherein said interrupt period is between about 0.10 milliseconds and about 1.0 milliseconds.

7. The accessor of claim 6, wherein each interrupt period is about 0.5 milliseconds in duration.

8. A method to diagnose the failure of an accessor movably disposed within an automated data storage system, said accessor retrieving one of a plurality of data storage media stored in a plurality of storage slots in said automated data storage system and delivering that retrieved data storage media to one of one or a plurality of data storage drives for reading and/or writing data thereon, said method comprising the steps of:

(a) providing an accessor comprising a first gripper comprising a first gripper motor and a first gripper motor tach, a pivot mechanism comprising a pivot motor and a pivot motor tach, a velocity control program, and a revolving memory buffer;

(b) generating first gripper motor tach information at a first time using said first gripper motor tach;

(c) determining using said first gripper motor tach information, and storing in said revolving memory buffer, a first tach position, a first demand velocity, a first PWM voltage, and a first actual velocity;

(d) generating pivot motor tach information at said first time using said pivot motor gripper tach;

(e) determining using said pivot motor tach information, and storing in said revolving memory buffer, a third tach position, a third demand velocity, a third PWM voltage, and a third actual velocity;

(f) generating at a second time updated first gripper motor tach information and updated pivot motor tach information; and

(g) determining if an accessor failure has occurred.

9. The method of claim 8, wherein said accessor further comprises a second gripper comprising a second gripper motor and a second gripper motor tach, said method further comprising the steps of:

(h) generating second gripper motor tach information at said first time using said second gripper motor tach;

(i) determining using said second gripper motor tach information, and storing in said revolving memory buffer, a second tach position, a second demand velocity, a second PWM voltage, and a second actual velocity;

(j) generating at said second time updated second gripper motor tach information.

10. The method of claim 9, wherein the difference between said first time and said second time comprises the interrupt period.

11. The method of claim 10, wherein said interrupt period is between about 0.1 milliseconds and about 1.0 milliseconds.

12. The method of claim 11, wherein said interrupt period is about 0.5 milliseconds.

13. The method of claim 9, further comprising the steps of:

(k) repeating steps (b) through (j) during a plurality of subsequent interrupt periods, so long as no accessor failure occurs; and

(l) terminating generation of updated first gripper motor tach information, updated second gripper motor tach information, and updated pivot motor tach information, if an accessor failure occurs.

14. The method of claim 13, wherein said first demand velocity is determined by said velocity control program.

15. The method of claim 14, wherein said first PWM voltage is the pulse width modulated voltage applied to said first gripper motor in order to attain said first demand velocity.

16. The method of claim 15, wherein said first actual velocity comprises the velocity of said first gripper determined at said first time.

17. The method of claim 13, further comprising the steps of:

(m) providing an external computer;

(n) downloading data stored in said revolving memory buffer to said external computer;

(o) analyzing said downloaded data; and

(p) determining the cause of said accessor failure.

18. The method of claim 17, wherein said external computer comprises a display device, said method further comprising the step of:

(q) graphically displaying said downloaded data on said display device.

19. The method of claim 17, wherein step (n) is performed using wireless communication.

20. An automated data storage system for storing and accessing a plurality of data storage media stored in a plurality of storage slots, said automated data storage system having at least one data storage drive for receiving said data storage media and reading and/or writing data thereon, said automated data storage system comprising:

one or a plurality of accessors for accessing and transporting said data storage media between said storage slots and said data storage drive, wherein said one or a plurality of accessors is moveably disposed within said automated data storage system;

wherein said one or a plurality of accessors each comprises;

an accessor control card having a revolving memory buffer;

a velocity control program stored on said accessor control card;

a first gripper disposed on said accessor;

a first gripper motor disposed on said first gripper;

a first gripper motor tach disposed on said first gripper motor, wherein said first gripper tach provides at a first time first gripper motor tach information to said velocity control program;

a pivot motor disposed on said accessor;

a pivot motor tach disposed on said pivot motor, wherein said pivot motor tach provides at said first time pivot motor tach information to said velocity control program;

wherein said velocity control program stores said first gripper motor tach information and said pivot motor tach information in said revolving memory buffer.

21. The automated data storage system of claim 20, further comprising:

a second gripper;

a second gripper motor disposed on said second gripper;

a second gripper motor tach disposed on said second gripper motor, wherein said second gripper tach provides at said first time second gripper motor tach information to said velocity control program;

wherein said velocity control program stores said first gripper motor tach information, said second gripper motor tach information, and said pivot motor tach information in said revolving memory buffer.

22. The automated data storage system of claim 21, wherein said one or a plurality of accessors each further comprise a wireless communication device.

23. The automated data storage system of claim 21, wherein said velocity control program determines and stores in said revolving memory buffer:

a first tach position, a first demand velocity, a first PWM voltage, and a first actual velocity using said first gripper motor tach information;

a second tach position, a second demand velocity, a second PWM voltage, and a second actual velocity using said second gripper motor tach information; and

a third tach position, a third demand velocity, a third PWM voltage, and a third actual velocity using said pivot motor tach information.

24. The automated data storage system of claim 21, wherein said first gripper motor tach provides to said velocity control program updated first gripper motor tach information obtained at a second time, and wherein said second gripper motor tach provides to said velocity control program updated second gripper motor tach information obtained at said second time, and wherein said pivot motor tach provides to said velocity control program updated pivot motor tach information obtained at said second time, wherein the difference between said first time and said second time comprises the interrupt period.

25. The accessor of claim 24, wherein said interrupt period is between about 0.10 milliseconds and about 1.0 milliseconds.

26. The accessor of claim 25, wherein each interrupt period is about 0.5 milliseconds.