Method and apparatuses for backgaging and sensor-based control of bending operations

Apparatus for actively damping vibration of a workpiece being held by a robot gripper during movement of said workpiece by a robot, said apparatus comprising:

• part geometry parameter reading means for reading part geometry parameters related to the workpiece being held by said robot gripper;
• force reading means for reading an amount of force between said workpiece and said robot gripper;
• frequency determining means for determining an approximate frequency of vibration of said workpiece based upon the force readings made by said force reading means;
• and
• robot movement control means for controlling said robot to move said robot gripper in a direction opposite to the force readings with the frequency determined by said frequency determining means.

Apparatus for controlling a robot having a robot gripper holding a workpiece, so that said workpiece is moved while maintaining contact between said workpiece and a desired object, said apparatus comprising:

• robot control means for controlling movement of said robot so that said workpiece moves in a desired direction;
• monitoring means for monitoring a force between said workpiece and said robot gripper;
• determining means for determining if the monitored force is within a certain range of a desired contact force between said workpiece and said desired object;
• and
• adjusting means for adjusting the direction of movement of said workpiece to either increase or decrease the contact force, as indicated by the monitored force between said workpiece and said robot gripper, in order to bring the monitored force within the certain range of the desired contact force.

Apparatus for controlling movement of a workpiece held by a robot gripper toward an obstacle until said workpiece contacts said obstacle, said apparatus comprising:

• robot control means for controlling movement of said workpiece by a predetermined increment toward said obstacle;
• force monitoring means for monitoring an amount of force between said workpiece and said robot gripper;
• determining means for determining if the monitored force is greater than or equal to a threshold value;
• and
• repeating means for repeating movement of said workpiece toward said obstacle until it is determined that the monitored force is greater than or equal to the threshold value.

Apparatus for controlling movement of a workpiece held by a robot gripper, and for detecting an unplanned impact between said workpiece and an obstacle, said apparatus comprising:

• monitoring means for monitoring an amount of force between said workpiece and said robot gripper;
• determining means for determining if the monitored force is greater than or equal to an impact threshold value;
• and
• stopping means for stopping movement of the robot when the monitored force is determined to be greater than or equal to said impact threshold value.

A system for loading a workpiece into a die space of a bending apparatus, said system comprising:

• measuring means for measuring an amount of droop offset of a leading edge of said workpiece before said workpiece is loaded into said die space;
• means for moving said workpiece in an upward direction by the measured droop offset;
• and
• loading means for loading said workpiece into said die space.

An angle sensor for detecting an angle of a flange portion of a workpiece as the flange portion is being bent by a bending apparatus, said angle sensor comprising:

• a member having a reflective surface;
• holding means for holding said member with said reflective surface against said flange portion of said workpiece;
• light emitting means for emitting a light beam onto said reflective surface;
• and
• light detecting means for detecting a position of said light beam as said light beam is reflected by said reflective surface, the detected position being indicative of the angle of said flange portion of said workpiece.