Stochastic scheduling of an automated two-machine robotic cell with in-process inspection system
- Authors: Foumani, Mehdi , Smith-Miles, Kate , Gunawan, Indra , Moeini, Ashgar
- Date: 2015
- Type: Text , Conference proceedings
- Relation: 45th International Conference on Computers and Industrial Engineering, CIE 2015; Universite de Lorraine, LCOMS Metz; France; 28th-30th October 2015. In Proceedings - CIE 45: 2015 International Conference on Computers and Industrial Engineering
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- Description: This study is focused on the domain of a two-machine robotic cell scheduling problem. Particularly, we propose the first analytical method for minimizing the partial cycle time of such a cell with a PC-based automatic inspection system to make the problem more realistic. It is assumed that parts must be inspected in one of the production machines, and this may result in a rework process. The stochastic nature of the rework process prevents us from applying existing deterministic solution methods for the scheduling problem. This study aims to develop an in-line inspection of identical parts using multiple contact/non-contact sensors. Initially, we present a heuristic method that converts a multiple-sensor inspection system into a single-sensor inspection system. Then, the expected sequence times of two different cycles are derived based on a geometric distribution, and finally the maximum expected throughput is pursued for each individual case.
Resolution of deadlocks in a robotic cell scheduling problem with post-process inspection system: Avoidance and recovery scenarios
- Authors: Foumani, Mehdi , Gunawan, Indra , Smith-Miles, Kate
- Date: 2015
- Type: Text , Conference proceedings
- Relation: 2015 IEEE International Conference on Industrial Engineering and Engineering Management, Singapore, 6th-9th December, 2015. p. 1107-1111
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- Description: The phenomenon of deadlock in robotic cells has been long ignored by most scheduling literature. A deadlock situation arises if a part cannot change its current state indefinitely since the destination machine is occupied by another part. The probability of the deadlock occurrence is likely to be large when the processing route cannot be predicted with certainty due to inspection processes. Our focus here is on a specific robotic cell with a post-process inspection system where the inspection is performed on an independent inspection machine. Avoidance and recovery policies are applied to overcome deadlocks originated from this cell. We develop these policies to prevent deadlock or alternatively resolve it during the online implementation of cycles. The former policy minimizes the storage cost, whereas the later policy minimizes the expected cycle time. An analysis of the scheduling problem that involves timings and costs is also carried out for comparing policies.
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
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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.