Robotic end effector system and method with lockable compliance

A method for manipulating a workpiece, the method comprising:

• constructing an arm to have a first section and a second section connected with the first section by a joint assembly, with a lock disposed in the joint assembly;
• connecting a first gripper with the first section of the arm;
• connecting a second gripper on the second section;
• gripping the workpiece simultaneously by the first gripper and the second gripper;
• releasing the workpiece from the first and second grippers;
• operating, by a controller, the lock to alternately lock and unlock the joint assembly, holding, by the first and second grippers, the workpiece during a deformation of the workpiece, with unlocking, by the controller, the lock to allow movement of the joint assembly;
• and relieving, by the unlocking, forces on the arm arising during a deformation of the workpiece.

A robotic system for manipulating a workpiece, the robotic system comprising:

• an end effector having a fixture;
• a first arm connected with the fixture, the first arm having a first section and a second section connected with the first section by a first joint assembly, with a first lock disposed in the first joint assembly;
• a second arm connected with the fixture, the second arm having a third section and a fourth section connected with the third section by a second joint assembly, with a second lock disposed in the second joint assembly;
• a first gripper on the first section and a second gripper on the second section of the first arm, the first and second grippers configured to alternately grip and release the workpiece, simultaneously;
• a third gripper on the third section and a fourth gripper on the fourth section of the second arm, the third and fourth grippers configured to alternately grip and release the workpiece;
• and
• a controller configured to:
• control the first lock to alternately lock and unlock the first joint assembly;
• control the second lock to alternately lock and unlock the second joint assembly;
• control the first gripper and the second gripper to hold the workpiece during a deformation of the workpiece;
• and
• unlock at least one of the first lock and the second lock to allow movement of at least one of the first joint assembly and the second joint assembly to relieve forces on the at least one of the first arm and the second arm arising during a deformation of the workpiece.