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Is it possible to solve logistics route optimisation Problem with plant simulation ?

Hello All,

 

I was wandering if it is possible to optimise the routes for logitics , such as in case of Milk run.

The picture shows a small example of the situation.

A vehicle has to deliver many orders in one single run. There are many destinations. The vehicle run in a way so that all the orders are delievered to all the customers in one go and with the shortest possible path.

My question is, is it possible to find that shortest possible path with the help of plant simulation?

14 REPLIES

Re: Is it possible to solve logistics route optimisation Problem with plant simulation ?

Valued Contributor
Valued Contributor

Hi,

 

 

The way you put it I think you could approach it as a classic travelling salesman problem. https://en.wikipedia.org/wiki/Travelling_salesman_problem

 

There are plenty of algorithms out there that you can use to solve this problem. Naturally, if you can program the algorithm in another language, you can also program it in SimTalk. I wouldn't recommend trying to make it into an integer linear program, since that would yield an exact solution but take too long to build.

 

If the number of customers is relatively limited, and exact optimization is important, you could try a dynamic programming approach. If approximate optimization is sufficient or the number of customers on a single run is too high, a nearest-neighbor solution might suit your needs.

 

You will need to define a distance matrix. I would recommend using a table with the row and column indexes to represent the names of the customers or the object representing the customer location if you would also like a transporter to visit these customers afterwards.

 

Kind regards,

 

Kaspar

Re: Is it possible to solve logistics route optimisation Problem with plant simulation ?

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor
if you use a routing list (as destination for the transporter) you could use the Genetic Algorithm to change the order of the destinations in the list, the fitness value would be transporter.traveledDistance --> minimize
Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net

Re: Is it possible to solve logistics route optimisation Problem with plant simulation ?

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

I have made a small  example. The only problem is: you need to delete the drain in the routing before optimization and add it in the init method again.

 

The example is version 13.1

Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net

Re: Is it possible to solve logistics route optimisation Problem with plant simulation ?

Thank you Mr. Bangsow. That is something really awesome!!!! Smiley Happy

Re: Is it possible to solve logistics route optimisation Problem with plant simulation ?

Hello Mr bangsow,

 

What does the integer represent in the table and which sequence is exactly the optimum sequence. I think that the transporter does not follow the sequnce from the table. I am bit confused here..Smiley Happy

Re: Is it possible to solve logistics route optimisation Problem with plant simulation ?

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor
the integer values are used by the GA, at the end of the optimization the GA sets the optimal variant in the routing table.
You can also use the numbers for sort the list (back to its starting order). The results you can find in the GA Assistant - Tab Evaluate - Best Individuals - Chrom --> als row numbers --> set the corresponding Targets in your routingtable
Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net

Re: Is it possible to solve logistics route optimisation Problem with plant simulation ?

Thank you Mr. Bangsow. 1 more query!! 

 

While making the model. What sequence should I write in the Ziele Table in the beginning. Does it play any role ?

 

Re: Is it possible to solve logistics route optimisation Problem with plant simulation ?

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor
it doesn't play a role
Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net

Re: Is it possible to solve logistics route optimisation Problem with plant simulation ?

If I change the sequence in the ziele table and again run it, The answer is different everytime and it is not optimal. Is there anything I am doing that I should not?