Accurate position control for fixtureless assembly

A method of performing a manufacturing operation, the method comprising:

• moving a part to a relative position via an end effector on a robot based on a local vision signal generated by a local vision sensor located on a movable part of the robot;
• sensing an absolute location of one of the part and the end effector via at least one remote vision sensor of a remote fixed vision system located apart from the robot and the end effector;
• generating a remote vision signal representative of the absolute location;
• comparing the absolute location with a predetermined desired location of at least one of the part and the end effector;
• repositioning the end effector and the part if the absolute location varies from the predetermined desired location by at least a threshold until the absolute location is within the threshold of the predetermined desired location;
• and
• performing an operation on the part when the absolute location is within the threshold of the predetermined desired location.

A part manufacturing system comprising:

• a part-moving robot having an end effector configured to grip a part and to move the part;
• an operation robot configured to perform an operation on the part, the part-moving robot being configured to hold the part while the operation robot performs the operation;
• a remote vision system located apart from the robots, the remote vision system having at least one remote vision sensor configured to sense an absolute location of at least one of the part and the end effector and to generate a remote vision signal representative of the absolute location;
• and
• a controller configured to collect the remote vision signal, the controller being further configured to compare the absolute location with a predetermined desired location of at least one of the part and the end effector, the controller being configured to send a repositioning signal to the part-moving robot if the absolute location varies from the predetermined desired location by at least a predetermined threshold, the part-moving robot being configured to move the part upon receiving the repositioning signal.

A manufacturing system comprising:

• an operation robot having a tool configured to perform an operation on a part;
• a remote vision system located apart from the operation robot, the remote vision system having at least one vision sensor configured to sense an absolute location of the tool and to generate a vision signal representative of the absolute location;
• and
• a controller configured to collect the vision signal, the controller being further configured to compare the absolute location with a predetermined desired location of the tool, the controller being configured to send a repositioning signal to the operation robot if the absolute location varies from the predetermined desired location by at least a predetermined threshold, the operation robot being configured to move the tool upon receiving the repositioning signal.