Automated robot alignment system and method using kinematic pins and end effector sensor

• US 7,236,853 B2
• Filed: 10/01/2004
• Issued: 06/26/2007
• Est. Priority Date: 10/01/2003
• Status: Active Grant

• Current Assignee: Varian Semiconductor Equipment Associates Incorporated (Applied Materials Incorporated)
• Original Assignee: Varian Semiconductor Equipment Associates Incorporated (Applied Materials Incorporated)
• Inventors: Stone, Stanley W., Daniels, Kevin M.
• Primary Examiner(s): Pham; Thomas K.
• Application Number:
  US10/956,309
• Publication Number:
  US 20050240290A1
• Time in Patent Office: 998 Days
• Field of Search: 700/64, 700/69, 700/70, 700/186, 700/193, 700/194, 700/251, 700/252, 700/262, 700/245, 318/568.11, 318/568.12, 318/569.19
• US Class Current: 700/245
• CPC Class Codes: B25J 9/1692 Calibration of manipulator
• CPC Class Codes: G05B 2219/39015 With different manipulator configurations, contact known sphere, ballbar
• CPC Class Codes: G05B 2219/45056 Handling cases, boxes

Abstract

A method and system can align a robot arm with a payload station. A probe and a contact detector may be positioned on the robot arm and three pins may be placed on the payload station. A controller may move the robot arm in a pattern over the payload station until contact may be made between the probe and one of the pins. A search about the contact location may be performed to obtain additional contacts. The search may be interrupted when contact is made between the probe and one of the pins. The position of the pin may be calculated from three such contacts on the spherical portion of the pin. The location of the probe at the time of contact may be stored and a localized search about the pin location may be performed. If the position of the pin cannot be resolved from three contacts, additional contacts may be made until a combination of three contacts does provide a solution. Three such pins may be so located such that the robot arm may learn the position of the payload station without operator intervention.

Claims

1. A method for aligning a movable arm with a target, comprising the steps of:

bringing a spherical portion of a probe on the movable arm in contact with a pin on the target, the probe contacting the pin at a first probe position;

moving the probe to contact the pin at two additional probe positions;

determining a location of the pin based on the location being a solution for an intersection of three spheres, each of the spheres being centered at a respective one of the probe positions and having a radius equal to a radius of the spherical portion of the probe plus a radius of a spherical portion of the pin;

moving the probe to contact the pin at a further probe position when there is no solution for the intersection of the three spheres and returning to determining the location; and

repeating the steps of bringing, storing, moving and determining for at least two additional pins on the target when the solution is determined.

2. The method of claim 1, wherein the step of bringing comprises:

positioning the probe at a predetermined position with respect to an anticipated location of the target;

moving the probe in a pattern in a plane parallel to the anticipated plane of the target, the pattern covering an area corresponding to an anticipated target area;

moving the probe closer to the anticipated plane of the target when no contact has been made during the step of moving the probe in the pattern; and

repeating the steps of moving the probe in the pattern and moving the probe closer until the contact is made.

3. The method of claim 1, wherein the step of moving the probe to contact the pin comprises the step of moving the probe in a predetermined pattern about possible locations of the pin based on the first probe position.

4. The method of claim 1, further comprising the steps of:

storing the position of the probe when contact is made; and

retrieving stored positions of the probe to determine the location of the pin.

5. The method of claim 1, further comprising the step of programming a processing system to control movement of the movable arm.

6. The method of claim 1, further comprising the step of controlling movement of the probe by operator manipulation of the movable arm.

7. The method of claim 1, further comprising the step of using the further probe position and combinations of two previous probe positions to determine the location of the pin when there is no solution using the previous probe positions.

8. A system for aligning a movable arm with a target, comprising:

a probe having a spherical portion and mounted on the movable arm;

at least three pins, each of the pins baying a spherical portion and mounted on the target;

a controller controlling movement of the movable arm;

a contact detector detecting at least three contacts between the spherical portion of the probe and each of the three pins; and

a processor determining locations for the pins based on probe positions when the contacts are detected from an intersection of three spheres being centered at respective probe positions.

9. A method for aligning a movable arm with a target, comprising the steps of:

bringing a probe on the movable arm in contact with a pin on the target, the probe contacting the pin at a first probe position;

moving the probe to contact the pin at additional probe positions;

determining a location of the pin based on the location being a solution of possible locations for the pin determined from the respective probe positions;

moving the probe to contact the pin at further probe positions when the solution is not obtained and returning to determining the location; and

repeating the steps of bringing, moving and determining for additional pins on the target.

10. A method for aligning a movable arm with a target, comprising the steps of:

bringing a spherical portion of a probe on the movable arm in contact with a spherical portion of a pin on the target, the probe contacting the pin at a first probe position;

moving the probe to contact the spherical portion of the pin at least two additional probe positions;

determining a location of the pin based on the location being an intersection of at least three spheres, each of the spheres being centered at a respective one of the first and the at least two additional probe positions and having a radius equal to a radius of the spherical portion of the probe plus a radius of the spherical portion of the pin; and

repeating the steps of bringing, moving and determining for at least two additional pins on the target.

11. The method of claim 10, wherein the step of bringing comprises:

positioning the probe at a predetermined position with respect to an anticipated location of the target;

moving the probe in a pattern in a plane parallel to the anticipated plane of the target, the pattern covering an area corresponding to an anticipated target area;

moving the probe closer to the anticipated plane of the target when no contact has been made during the step of moving the probe in the pattern; and

repeating the step of moving the probe in the pattern and moving the probe closer until the contact is made.

12. The method of claim 10, wherein the step of moving the probe to contact the spherical portion of the pin comprises the step of moving the probe in a predetermined pattern about possible locations of the pin based on the first probe position.

13. The method of claim 10, further comprising the steps of:

storing the position of the probe when contact is made; and

retrieving stored positions of the probe to determine the location of the pin.

14. The method of claim 10, further comprising the step of programming a processing system to control movement of the movable arm.

15. The method of claim 10, further comprising the step of controlling movement of the probe by operator manipulation of the movable arm.

16. A system tin aligning a movable arm with a target, comprising:

a probe having a spherical portion and mounted on the movable arm;

at least three pins, each of the pins having a spherical portion and mounted on the target,

a controller controlling movement of the movable arm;

.

a contact detector detecting at least three contacts between the spherical portion of the probe and each of the spherical portions of the three pins; and

processor determining locations for the pins based on probe positions when the contacts are detected from an intersection of three spheres being centered at respective probe positions.

17. A method for aligning a movable arm with a target, comprising the steps of:

bringing a probe on the movable arm in contact with a pin an the target, the probe contacting at a first probe position;

moving the probe to contact the pin at additional probe positions;

determining a location of the pin based on the location being a solution of possible locations for the pin determined from the first and additional probe positions; and

repeating the steps of bringing, moving and determining for additional pins on the target.