Location Calibration for Automated Production Manufacturing

A method for performing an automated function on successive workpieces, said method comprising:

• (a) placing a first workpiece in a workcell at a first location while a robot base of a robot is situated at a second location;
• (b) placing a positioning system at a third location so that a laser and a camera of the positioning system have non-occluded views of a plurality of target markers on the first workpiece and a plurality of target markers on the robot base;
• (c) using the positioning system to separately measure respective positions of the target markers on the first workpiece and the target markers on the robot base;
• (d) calculating a first offset of the first workpiece at the first location relative to the robot base at the second location based on position information acquired in process (c);
• (e) creating a motion plan program for moving an end effector of the robot along a first motion path, the motion plan program being based at least in part on the first offset;
• (f) loading the motion plan program into a robot controller of the robot;
• (g) controlling the robot so that the end effector moves along the first motion path while the first workpiece is situated at the first location and performs an automated function on the first workpiece while the end effector is at a specified location along the first motion path;
• (h) removing the first workpiece from the workcell after process (g);
• (i) placing a second workpiece at a fourth location in the workcell after the first workpiece has been removed and while the robot base is situated at a fifth location in the workcell;
• (j) placing the positioning system at a sixth location so that the laser and the camera of the positioning system have non-occluded views of a plurality of target markers on the second workpiece and the plurality of target markers on the robot base, wherein the sixth location may be the same or different than the third location;
• (k) using the positioning system to separately measure respective positions of the plurality of target markers on the second workpiece and the plurality of target markers on the robot base;
• (l) calculating a second offset of the second workpiece at the fourth location relative to the robot base at the fifth location based on position information acquired in process (k);
• (m) modifying the motion plan program for moving the end effector of the robot along a second motion path different than the first motion path based at least in part on a difference between the first and second offsets;
• and
• (n) controlling the robot so that the end effector moves along the second motion path while the second workpiece is situated at the fourth location and performs an automated function on the second workpiece while the end effector is at a specified location along the second motion path.

A method for performing an automated function on a stiffener of a workpiece, said method comprising:

• (a) placing a workpiece having a stiffener in a workcell at a first location while a robot base of a robot is situated at a second location;
• (b) loading a motion plan program into a robot controller of the robot, the motion plan program being written to control the robot so that an end effector of the robot will:
• (i) move along a first motion path that is based on an expected position in a coordinate system of the workcell of a point on a stiffener of a workpiece having a structure similar to the workpiece at the first location;
• and (ii) perform an automated function on the stiffener while the end effector is at a specified location along the first motion path;
• (c) placing a positioning system at a third location so that a laser and a camera of the positioning system have non-occluded views of a plurality of target markers on the workpiece, a plurality of target markers on the robot base, and a target marker at the point on the stiffener;
• (d) using the positioning system to separately measure respective positions of the plurality of target markers on the workpiece, the plurality of target markers on the robot base, and the target marker at the point on the stiffener;
• (e) calculating an offset of a position of the point on the stiffener of the workpiece at the first location relative to the expected position based on position information acquired in process (d);
• (f) modifying the motion plan program for moving the end effector of the robot along a second motion path that is different than the first motion path based at least in part on the calculated offset;
• and
• (g) controlling the robot so that the end effector moves along the second motion path and performs an automated function on the workpiece while the end effector is at a specified location along the second motion path.

A method for performing an automated function on stiffeners of a workpiece, said method comprising:

• (a) placing a workpiece having at least first, second and third stiffeners in a workcell at a first location while a robot base of a robot is situated at a second location, the second stiffener being between the first and third stiffeners;
• (b) loading a motion plan program into a robot controller of the robot, the motion plan program being written to control the robot so that an end effector of the robot will:
• (i) move along a first motion path adjacent to the first stiffener of the workpiece that is based on an expected position in a coordinate system of the workcell of a point on the first stiffener;
• and (ii) perform an automated function on the first stiffener while the end effector is at a specified location along the first motion path;
• (c) placing a positioning system at a third location so that a laser and a camera of the positioning system have non-occluded views of respective target markers at respective points on the first, second and third stiffeners of the workpiece;
• (d) using the positioning system to measure a position of the target marker on the second stiffener;
• (e) calculating an offset of the position of the point on the second stiffener relative to the expected position of the point on the first stiffener based on position information acquired in process (d);
• (f) modifying the motion plan program for moving the end effector of the robot along a second motion path adjacent the second stiffener based at least in part on the calculated offset;
• and
• (g) controlling the robot so that the end effector moves along the second motion path and performs an automated function on the second stiffener while the end effector is at a specified location along the second motion path.