Notes on feasibility and optimality conditions of small-scale multifunction robotic cell scheduling problems with pickup restrictions
- Authors: Foumani, Mehdi , Gunawan, Indra , Smith-Miles, Kate , Ibrahim, Yousef
- Date: 2015
- Type: Text , Journal article
- Relation: IEEE Transactions on Industrial Informatics Vol. 11, no. 3 (2015), p. 821-829
- Full Text: false
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- Description: Optimization of robotic workcells is a growing concern in automated manufacturing systems. This study develops a methodology to maximize the production rate of a multifunction robot (MFR) operating within a rotationally arranged robotic cell. An MFR is able to perform additional special operations while in transit between transferring parts from adjacent processing stages. Considering the free-pickup scenario, the cycle time formulas are initially developed for small-scale cells where an MFR interacts with either two or three machines. A methodology for finding the optimality regions of all possible permutations is presented. The results are then extended to the no-wait pickup scenario in which all parts must be processed from the input hopper to the output hopper, without any interruption either on or between machines. This analysis enables insightful evaluation of the productivity improvements of MFRs in real-life robotized workcells. ©2014 IEEE.
Scheduling dual gripper robotic cells with a hub machine
- Authors: Foumani, Mehdi , Ibrahim, Yousef , Gunawan, Indra
- Date: 2013
- Type: Text , Conference proceedings
- Relation: Industrial Electronics (ISIE), 2013 IEEE International Symposium, Taipei, Taiwan, 28th-31st May 2013 p1-6
- Full Text: false
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- Description: This paper introduces a new methodology to optimise the cycle time of dual-gripper robotic workcells. The workcell under study is composed of a group of m production machines. In order to produce a completed part, a chain of m-1 secondary operations are performed by m-1 different machines, and a hub machine is alternately visited for m primary operations. Indeed, parts must reenter the hub machine after any one of secondary operations. Those types of robotics workcells are used for high capacity production such as in photolithography manufacturing, These cells are cluster tools for semiconductor manufacturing where a wafer visits a processing stage several times for the atomic layer deposition (ALD) processes. For electroplating lines, these cells are also common in practice where there is a multifunction production stage that is visited by parts over once. This optimisation methodology is limited to the dual-gripper robotic cells, where identical parts are produced and these parts completely follow a similar sequence. The lower bound of cycle time for such dual-gripper robotic cells is obtained by finding the cycle time of all related robot move cycles, and subsequently optimal robot task sequence, which is a two-unit cycle, is determined.