The present disclosure generally relates to pick and place robotic systems. A compliance mechanism comprising: a motion device; an end effector coupled to the motion device, wherein the end effector comprises: a sheath structure; a rod, wherein the compliance mechanism is configured to: when the distal end of the rod is in not contact with an object, causing the distal end of the rod to move responsive to movement of the motion device, and when the distal end of the rod is in contact with an object and the motion device moves toward the object, causing the distal end of the rod to remain stationary by causing the sheath structure to move along a longitudinal direction of the rod.