Methods and apparatus for backgaging and sensor-based control of bending operation

Apparatus for executing a bend on a malleable sheet workpiece with bend-following, said apparatus including a bending apparatus, said bending apparatus comprising a die, a tool punch, and a robot gripper for holding said workpiece, said apparatus comprising:

• reading means for reading a position value indicative of the relative movement of said die with respect to said tool punch;
• calculating means for calculating the location of said gripper as it holds onto said workpiece as a function of the position data read by said reading means;
• speed control means for limiting the speed of said relative movement of said die with respect to said tool punch so that said calculated location does not change too rapidly;
• means for detecting a force between said workpiece and said robot gripper during execution of said bend;
• means for modifying the location calculated by said calculating means based upon the detected force;
• robot control means for controlling movement of said robot to correspond to the calculated location;
• and
• determining means for determining if a final bend angle has been reached signifying completion of the bend.

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;
• a holder that holds said member with said reflective surface against said flange portion of said workpiece;
• a light emitter that emits a light beam onto said reflective surface;
• and
• a light detector that detects 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.

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, the angle sensor comprising:

• a member having a reflective surface;
• a holder that holds the member with the reflective surface against the flange portion of the workpiece;
• a light emitter that emits a light beam onto the reflective surface;
• and
• a light detector that detects a position of the light beam as the light beam is reflected by the reflective surface, the detected position being indicative of the angle of the flange portion of the workpiece,
• wherein the reflective surface is movable towards and away from the flange portion.

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, the angle sensor comprising:

• a member having a reflective surface;
• an arm for supporting the member, the arm being rotatable about an axis parallel to a bending line to be formed in the workpiece by the bending apparatus;
• a light emitter that emits a light beam onto the reflective surface;
• and
• a light detector that detects the position of the light beam as the light beam is reflected by the reflective surface, the detected position being indicative of the angle of the flange portion of the workpiece.