Robot move scheduling optimization for maximizing cell throughput with constraints in real-life engineering

Industrial robot is proven to be more cost effective in terms of flexibility, repeatability, and with new functions offer improved accuracy. Since the parts produced in a robotic cell are identical, it is sufficient to determine the sequence of robot moves, in case of single- or dual-gripper, to implement the tasks. How to achieve the maximum/near-maximum throughput in a robotic cell, even a small improvement in throughput, is always the highlighted objective in engineering practice, especially in 3C industry of communication, computer and consumer electronics. The optimality in cell layout and optimistic robot move scheduling come from robotic cell throughput optimization viewpoint, in terms of the steady state cycle time to produce a part. In this paper, an analytical framework for scheduling moving of robot with single- or dual-gripper is developed. Initially different constraints are considered in validation, including interval/free pick up, non-free/free process, and inadmissible path. It is indicated that a dual-gripper robot can gain an improvement in throughput in most cases. The resulting diagrams provide a clear overview of the scheduling and links between throughput and cell pattern, by comparing the resulting increase in revenue with the additional equipment costs.