- 1. Graduate Seminar - Deadlock Avoidance in FMS, June
2002Deadlock Avoidance Methodsin Flexible Manufacturing Systems
Jacob Rubinovitz Technion - Israel Institute of Technology Faculty
of Industrial Engineering & Mgmt. Dr. Jacob Rubinovitz
2. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Introduction: Flexible Manufacturing SystemsAn automatic,
programmable manufacturing systemVolume TransferLinesDedicated CIM
SystemsFlexibleSystems Automated CellsJob Shops VarietyDr. Jacob
Rubinovitz 3. Graduate Seminar - Deadlock Avoidance in FMS, June
2002 Introduction: Flexible Manufacturing SystemsComponents of the
SystemProgrammable machines (CNC, Robots)Flexible tools and
fixtures Flexible MH systems (AGVs, Robots)Automated Storage and
Retrieval SystemComputer controlDr. Jacob Rubinovitz 4. Graduate
Seminar - Deadlock Avoidance in FMS, June 2002Introduction:
Flexible Manufacturing Systems Dr. Jacob Rubinovitz 5. Graduate
Seminar - Deadlock Avoidance in FMS, June 2002Introduction:
Flexible Manufacturing Systems Dr. Jacob Rubinovitz 6. Graduate
Seminar - Deadlock Avoidance in FMS, June 2002Deadlock-free
operation is crucialto the operation of an FMSResearch of Deadlock
Avoidance Methods: Evaluation of different policies. Integration of
avoidance policies into the controlsoftware of Flexible
Manufacturing Cells. A joint work with Jean-David Salama.Dr. Jacob
Rubinovitz 7. Graduate Seminar - Deadlock Avoidance in FMS, June
2002Deadlock - backgroundParts in FMS compete for a finite number
ofresources (like robots, tools, pallets, fixtures, etc),and share
buffers or queues having limitedcapacities. A deadlock state occurs
when each process in a set of processes is blocked indefinitely
from access to resources held by other processes within the set. A
good FMS control method must resolve or avoid all the potential
deadlocks during operation, without seriously degrading the system
performance Dr. Jacob Rubinovitz 8. Graduate Seminar - Deadlock
Avoidance in FMS, June 2002Necessary conditions for deadlocks
Mutual exclusion: resources can be allocated to only one process at
a time. No preemption: resources held by one process cannot be
allocated to another process until they are released by the process
holding them. Hold and wait: processes hold their resources when
waiting for the next required resources. Circular wait: closed
chain of processes, where each process waits for a resource held by
the next process in the chain. Dr. Jacob Rubinovitz 9. Graduate
Seminar - Deadlock Avoidance in FMS, June 2002Part Flow Deadlock
Machine M1Machine M2P1: M1M2(No Buffer )(No Buffer )P2: M2M1Part
P1Part P2 M1M2) MHD(M2M1 M2 P1: M1M2 M1 P2: M2M3 P3: M3M1M3P1: M1M2
M3P2: M2M3P3: M3M1Dr. Jacob Rubinovitz 10. Graduate Seminar -
Deadlock Avoidance in FMS, June 2002Methods for handling
DeadlocksDetection/Recovery (Wysk et al., 1994)Prevention System
design, such thatdeadlocks are impossible(Epzeleta et al.,
1995;Minoura and Ding, 1991;Viswanadham et al., 1990)Avoidance a
control policy thatexamines each request for resourceallocation
prior to its execution (Banaszak and Krogh,1990; Ferrarini and
Maroni,1998; Hsieh and Chang,1994; Lee and Lin, 1995; Revelotis and
Ferreira,1996; Xing et al.,1996;Yim et al.,1990) Dr. Jacob
Rubinovitz 11. Graduate Seminar - Deadlock Avoidance in FMS, June
2002 (Capacity-Designated Graph (CDG Mi Ni3 IBiA machine and its
CDG node.Yim, D.S., Kim, J.I. and Woo, H.S. (1997) Avoidance of
deadlocksin flexible manufacturing systems using a
capacity-designateddirected graph. International Journal of
Production Research, 35(9), 2459-2475. Dr. Jacob Rubinovitz 12.
Graduate Seminar - Deadlock Avoidance in FMS, June 2002
(Capacity-Designated Graph (CDG
N2|N|=4,N1A12=A21=A24=A43=A32=A14=A41=1 2 2A42=A13=A31=A34=A23=0
N4X={1,2,0,1} N3C={2,2,1,3}3 1 Fully detailed CDG graph
G=(N,A,X,C).Yim, D.S., Kim, J.I. and Woo, H.S. (1997) Avoidance of
deadlocksin flexible manufacturing systems using a
capacity-designateddirected graph. International Journal of
Production Research, 35(9), 2459-2475. Dr. Jacob Rubinovitz 13.
Graduate Seminar - Deadlock Avoidance in FMS, June 2002Loops in a
Capacity-Designated Graph N2 N1 Cycle S1: N1N2N1N1N2N3 Cycle S2:
N1N2N4N1 Cycle S3: N2N4N3N2N4 CDGAG=(N,A) Cycle S : N N
NN3containing 57 cycles. 4 14 1 Cycle S : N1N N3N2N1 A CDG G=(N,A)
containingN5 cycles. 4 55N4 NN!Smax =[ i =1 (N -i) !i ] -NDr. Jacob
Rubinovitz 14. Graduate Seminar - Deadlock Avoidance in FMS, June
2002Loops in a Capacity-Designated GraphN2N1 N3A CDG
G=(N,A)containing 57 cycles. N5N4 Routing Intensity IndexN N A i =
1 j =1,j = iij RII =; 0
