Robot diagnosing method
A robot diagnosing method detects a deviation amount caused by a lost motion and includes: a first step of preparing a robot including a robot arm having at least one joint portion, a work conveyed by the robot, and a prealigner including a processing portion configured to detect a center position of the work; and after the first to fifth steps, a sixth step of detecting the deviation amount caused by the lost motion at the one joint portion based on (i) the center position of the work based on the center position of the work detected in the second step and a command value from a robot control portion in the fourth step and (ii) the center position of the work detected in the fifth step.
1. A robot diagnosing method of detecting a deviation amount caused by a lost motion,
the robot diagnosing method comprising:
a first step of preparing
a robot including a robot arm having at least one joint portion, an end effector attached to the robot arm, and a robot control portion configured to control the robot arm and the end effector,
a work conveyed by the robot, and
a prealigner including a turn table on which the work is placed, a driving portion configured to rotate the turn table, a sensor configured to detect an outer edge portion of the work that is being rotated by the driving portion, and a processing portion configured to detect a center position of the work based on the outer edge portion detected by the sensor;
a second step of placing the work on the turn table by the end effector and detecting the center position of the work by the prealigner;
a third step of, after at least the first and second steps are performed, holding by the end effector the work placed on the turn table;
a fourth step of, after at least the first and second steps are performed, rotating one of the at least one joint portion in a first direction by a predetermined angle based on a command value from the robot control portion;
a fifth step of, after the first to fourth steps are performed, placing the work on the turn table by the end effector and detecting the center position of the work again by the prealigner; and
a sixth step of, after the first to fifth steps are performed, detecting the deviation amount caused by the lost motion at the one joint portion based on (i) the center position of the work based on the center position of the work detected in the second step and the command value from the robot control portion in the fourth step and (ii) the center position of the work detected in the fifth step.
2. The robot diagnosing method according to claim 1 , wherein the fourth step is performed after the first to third steps are performed.
3. The robot diagnosing method according to claim 1 , wherein:
the third step is performed after the first, second, and fourth steps are performed; and
in the fifth step, the end effector is returned to the same position as when the end effector places the work on the turn table in the second step, and the end effector then places the work on the turn table.
4. The robot diagnosing method according to claim 2 , wherein:
in the first step, an accommodating portion configured to accommodate the work is further prepared;
in the second step,
postures of the robot arm and the end effector are set by a predetermined first motion such that the work accommodated in the accommodating portion is holdable by the end effector,
the end effector holds the work,
the postures of the robot arm and the end effector are set by a predetermined second motion such that the work is placeable on the turn table,
the work is then placed on the turn table, and
the prealigner detects the center position of the work;
in the fourth step performed after the first to third steps are performed,
the postures of the robot arm and the end effector are set by the predetermined first motion such that the work is accommodatable in the accommodating portion,
the work is accommodated in the accommodating portion, and
one of the at least one joint portion is then rotated in the first direction by a predetermined angle based on the command value from the robot control portion;
in the fifth step performed after the fourth step is performed,
the end effector holds the work accommodated in the accommodating portion,
the postures of the robot arm and the end effector are set by the predetermined second motion such that the work is placeable on the turn table,
the work is then placed on the turn table, and
the prealigner detects the center position of the work again; and
in the sixth step performed after the first to fifth steps are performed, the deviation amount caused by the lost motion at the one joint portion when the postures are set such that the work is accommodatable in the accommodating portion is detected based on (i) the center position of the work based on the center position of the work detected in the second step and the command value from the robot control portion in the fourth step and (ii) the center position of the work detected in the fifth step.
5. The robot diagnosing method according to claim 1 , wherein the first direction in which the one joint portion is rotated in the fourth step is opposite to a direction in which the one joint portion is rotated immediately before the work is placed on the turn table in the second step.
6. The robot diagnosing method according to claim 1 , wherein in the first step, the work, the robot, and the prealigner are prepared in a clean room that is a semiconductor manufacturing site.
7. The robot diagnosing method according to claim 6 , wherein in the first step, the accommodating portion is prepared in the clean room that is the semiconductor manufacturing site.
8. The robot diagnosing method according to claim 1 , wherein the work is a semiconductor wafer.