Optimization Algorithms for Flexible Production Scheduling - thanks to : P. Sucha, I. Modos, Z.Baumelt Czech Institute of ...

Optimization Algorithms for
Flexible Production Scheduling

                Zdenek.Hanzalek@cvut.cz
        thanks to : P. Sucha, I. Modos, Z.Baumelt
 Czech Institute of Informatics, Robotics and Cybernetics
             Faculty of Electrical Engineering
           Czech Technical University in Prague

Supply Chain Management and
                   Scheduling

     Sales         Material      Production    Distribution

•   Supply chain is driven by the customer demand
•   Production needs to be very flexible
•   Scheduling and rescheduling is needed to achieve efficiency

Application:
Flexible planning and scheduling in
         printing company

Planning and Scheduling

Planning layer - typically in ERP
• Works with cumulative capacities in
  buckets of time (like day-week)
• Loads operations into buckets
• No account of sequencing,
  precedences, set-up time

Scheduling layer
• Exact start time of each operation
• Completion time of job is known
• Operations allocated to machines
• Takes into account set-up times,
  types of resources, transport times
• Brings savings and order

Flexibility

   Mike Tyson: „Everybody has a plan - until he gets hit.“

Manufacturing is hit very often:
                                           Integration with
• Machine breakdown
                                           MES
• Material unavailability      Solution    &
                                           Rescheduling
• Order with high priority
• Sick-leave of personnel

Resource productivity and efficiency

                 ERP
             •   Orders
             •   Material
             •   Know-how          Flexible
                                  Scheduling
                 CPS
            • Events

Processes   Information Systems    Algorithms

Machine‐Uptime in Printing
                Company
•   Optimization algorithm coupled with existing ERP
    •   Recalculation of the production plan every 30 minutes

    •   Objective is a maximal use of the most expensive machines

    •   Sales personnel adjust timing/price of orders up to the available capacities

    •   Uptime increase from 30% to 40% due to the reduction of changeover times

    •   Fully automated

Users and their roles

Sales                          Foreman

•   inserts jobs               • sees a schedules/status

Planner                        Worker

•   checks availability of     • sees a sequence of operations
    resources                  Warehouseman
•   adapts global schedules    • bill of materials to be ready

Fabrio – internet service

Histogram of Up‐time
             Before and After
100
 90
 80
 70
 60
 50                                     2014 avg 41,3%
 40                                     2012 avg 30,5%
 30
 20
 10
  0
        0
       20
       40
       60
       80
      100
      120
      140
      160
      180
      200
      220
      240
      260
      280
      300
      320
      340
      360
 • Today – increasing number of small orders
 • Replacement of sales personnel by Web2Print

Case Study:
   Robust Scheduling with Energy
Consumption Limits in Glass Hardening

Robust Scheduling with
                Energy Consumption Limits

• Energy-aware scheduling
  – consumption limits
  per 15 mins
• Uncertainty of execution
  – disruptions, materiál, …
• Robustness of the
  schedule is a necessity to
  avoid panalties
• Development of exact and
  heuristic alorithms

Case Study:
        Energy efficiency of Skoda Gear
             Box Production Line
Production line for automatic gear box consists of:
1. machine tools center
2. hardening line
3. assembly

Energy Efficiency of Hardening Line

•   hardening is the most
    energy consuming stage
•   CURRENT SITUATION:
    even if a hardening
    furnaces is not used it is
    not switched-off due to
    the luck of the schedule
•   SOLUTION: The aim is to
    switch between
    operational and standby
    modes of hardening
    furnaces
•   relation between
    production scheduling and
    cost of energy

Case Study:
Robotic Welding Cells in
  Car Manufacturing

Parameter and Code Generation
                   in Digital Factory

• Generation of
  parameters and real
  robot programs
• Cycle‐time and energy
• Order of operations
• Robot trajectories ‐
  movements, spot
  welding
• Shared zones ‐ robots    Tecnomatix Process Simulate
  must avoid collisions Real Experiments by Blumenbecker

Robot Energy Consumption

We consider the following categories of saving:

 1. selection of stationary positions
 2. power save modes
 3. trajectory selection
 4. speed of movement
 5. order of operations

Tasks and Precedence Constraints
    ●   graph representing two robots

●       schedule

Personnel scheduling

Set of employees with qualifications         labour code
Set of shifts                                collective agreement
Set of constraints         all shifts assignment, coverage

                                                               …
Multiobjective criterion   minimal time gaps between shifts,
                                    maximal length of blocks, balancing
Goal - to assign required shifts to employees with respect to
given constraints

                       Department of Control Engineering   …

Verification of real-time systems

                                                • timed automata, temporal
                                                  logics
                                                • cooperative-preemptive
                                                  scheduling
                                                • case studies in automotive
                              CP-highin [1,2]
                                                  sector
 Finishing time
     P-high                   CP-lowin [1,2]    • modelling of fault tolerant
    2                                             systems
    1                                           • distributed applications
    0
                              Finishing time
                                   P-low          based on CAN
        0   1     2   3   4
• Waszniowski, L. - Hanzálek, Z.: Formal Verification of Multitasking
  Applications Based on Timed Automata Model, Real-Time Systems,
  Volume 38, Number 1, January 2008
• Waszniowski, L. - Krákora, J. - Hanzálek, Z.: Case Study on
  Distributed and Fault Tolerant System Modelling Based on Timed
  Automata. Journal of Systems and Software, 2009

Message Scheduling for
                     Profinet IO IRT
                                         Formulated as PS|temp|Cmax

Tree topology
• switch integrated in each node
• data are forwarded according to
   a static communication schedule

Hanzálek, Burget, Šůcha, P.: IEEE Trans. on Industrial Informatics, 2010.

Parallel Optimization Algorithms

  Graphics Processing Unit
  • Collaboration with
    NVIDA (NDA, visits in
    Palo Alto)
  • solve combinatorial
    problems on GPUs
  Tabu Search algorithm
  • 10.5/42.7 times faster
    than the optimized
    parallel/sequential
    algorithm for the Central
    Processing Unit (CPU)
Bukata, Šůcha, Hanzálek: Journal of Parallel and Distributed Computing 2015

Journal papers in 2016
1.   Bukata, L. - Šůcha, P. - Hanzálek, Z. - Burget, P.: Energy Optimization of Robotic
     Cells, IEEE Transactions on Industrial Informatics, 2016.
2.   Módos, I. - Šůcha, P. - Václavík, R. - Smejkal, J. - Hanzálek, Z.: Adaptive online
     scheduling of tasks with anytime property on heterogeneous resources, Computers and
     Operations Research, December 2016, Volume 76, Pages 95–117, Elsevier.
3.   Václavík, R. - Šůcha, P. - Hanzálek, Z.: Roster evaluation based on classifiers for the
     nurse rostering problem, Journal of Heuristics, October 2016, Volume 22, Issue 5,
     Springer.
4.   Dvořák, J. - Hanzálek, Z.: Using Two Independent Channels with Gateway for FlexRay
     Static Segment Scheduling, IEEE Transactions on Industrial Informatics, October 2016.
5.   Hanzálek, Z. - Šůcha, P.: Time Symmetry of Resource Constrained Project Scheduling
     with General Temporal Constraints, Annals of Operations Research, Springer.
6.   Minaeva, A - Šůcha, P. - Akesson, B. - Hanzálek, Z.: Scalable and Efficient
     Configuration of Time-Division, Journal of Systems and Software, March 2016, Volume
     113, Elsevier.
7.   Hanzálek, Z. - Tunys T. - Šůcha, P.: An Analysis of the Non-preemptive Mixed-criticality
     Match-up Scheduling Problem, Journal of Scheduling, October 2016, Volume 19, Issue
     5, pp 601–607, Springer.
8.   Bäumelt, Z. - Dvořák, J. - Šůcha, P. - Hanzálek, Z.: A Novel Approach for Nurse
     Rerostering based on a Parallel Algorithm, European Journal of Operational Research,
     June 2016, Volume 251, Issue 2, Elsevier.

Awards in 2016

Excellent Research Results in Technical Sciences
•   evaluation was based on impact of the paper measured in terms of
    contracts and citations
•   our group got 2 results out of 42 awarded in Technical Sciences in the
    Czech Republic

Hanzálek, Z. - Burget, P. - Šůcha, P.: Profinet IO
IRT Message Scheduling with Temporal
Constraints. IEEE Transactions on Industrial
Informatics, August 2010.

Hanzálek, Z. - Jurčík, P.: Energy efficient
scheduling for IEEE 802.15.4/ZigBee. IEEE
Transactions on Industrial Informatics. 2010.

Projects and Contracts in 2016

1. HERCULES - High-Performance Embedded Real-time
   Architectures for Low-Power Many-Core Systems, European
   Commission 688860. Horizon 2020.
2. FOREST - Flexible Scheduling and Optimization Algorithms for
   Distributed Real-time Embedded Systems - GACR.
3. SALTT - Scheduling Algorithms for Time-Triggered Systems,
   Office of Naval Research Global N62909-15-1-N094, US Navy.
4. CAK 3 - Centre for Applied Cybernetics - TACR.
5. eRobot – Energy efficiency of robotic welding cells – Ministry of
   Industry and Trade.