Colloquia

Samenvatting

Since many decades, forklifts are an often used tool for internal material transportation due to their high versatility. This versatility comes at the price of relatively high operation cost, mainly due to high consumption of human resources. It is therefore highly important that forklifts are deployed efficiently. This can be achieved by ensuring an adequate number of forklifts are present, and that these forklifts are routed to the correct job to maximize the amount of useful work a forklift can perform. To achieve these goals, two methods were proposed. 

To achieve the first goal, this study proposed a method of generating a forklift planning based on the expected production planning on a quantitative level. This is done by estimating the amount of jobs each production cycle on the production planning will be requesting, as well as timing of this job request. From this the forklift workload will be estimated, from which an adequate amount of forklifts can be calculated. 

For the second goal, this study researched a new method of dispatchment of forklifts to pending jobs by shifting job prioritization from arbitrary job deadlines to the job's impact on production buffers and  impact on forklift efficiency performance indicators. Also a component was built in to increase workplace workability by disincentivizing excess materials being present at production locations.

These methods are tested and optimized in a Siemens Plant Simulation model. The forklift planning algorithm was optimized to minimize the amount of forklifts under the constraint that planned production was not hindered. This optimized algorithm was tested for performance by comparing it to the absolute optimal amount of forklifts to plan, where it was found that it plans the optimal amount of forklifts in 76% of cases. The dispatching rule was optimized, after which the fraction of time forklifts drive empty was decreased from 45% to 40%. This, however, came at the cost of neglecting some jobs, causing them to be delivered way overdue.