The concept of natural motion for pick and place operations

Abstract

In pick and place operations a mechanism moves an object from an initial to a final pose and repeats, with frequencies of operation that can achieve 150 picks per minute. The paper presents the concept of natural motion for this kind of operations, where the basic idea is to add elastic elements to the mechanism and try to match the desired motion with the natural motion of the system. This concept was implemented in a multibody simulation of a five-bar linkage by using numerical optimization to find the required spring constants as well as the trajectory that minimize the torque on the motors. The required energy of the system using the concept of natural motion was compared with that of a typical trajectory, finding that the use of springs and natural motion reduces the energy consumption by 68% per cycle.