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Interactive optimizer

Assembly line balancing

A product is built from many small tasks, each taking some time and each with precedence constraints — some tasks can’t start until others finish. Those tasks have to be shared across an ordered line of workstations so that no station’s work exceeds the cycle time (the beat of the line). Pack them badly and you need extra stations and workers standing idle; pack them well and the line runs lean.

Here an artificial immune system searches for a good assignment: it clones and hypermutates the best candidate task-orderings each generation, keeping the ones that use fewer stations and spread the load more evenly. Raise or lower the cycle time and watch the number of stations and the line efficiency trade off; the outlined column is always the current bottleneck.

DEMO

This interactive is a faithful re-design of the research, simplified for illustrative and teaching purposes. It conveys the idea and behaviour of the model — it is not the paper’s full method, data, or results.

Type-E assembly line balancing · artificial immune system
Immune optimizer · clonal selection

Top: precedence graph, each node a task (its time) coloured by assigned station. Bottom: workstations filling with task-time blocks under the cycle-time limit (dashed); the outlined column is the current bottleneck. Raise or lower the cycle time and watch stations and efficiency trade off.

How the model works

Each candidate solution is a priority ordering of the tasks. A decoder walks that order, dropping each ready task (one whose predecessors are already placed) into the current workstation if it fits under the cycle time, and opening a new station the moment it doesn’t. Line efficiency is the total work divided by the number of stations times the cycle time — so fewer, fuller stations means a leaner line.

The immune optimizer treats good orderings as high-affinity antibodies: each generation it clones the best ones and hypermutates the clones (more mutation for weaker solutions), evaluates the offspring, and keeps the fittest — with a trickle of fresh random antibodies for diversity. Over generations the line balances itself, evening out station loads and shrinking the bottleneck. This mirrors the artificial-immune and bio-inspired methods in the papers below, applied to the type-E variant where both the cycle time and the number of stations are in play.

The research behind it

This demo is a teaching stand-in for a body of work on assembly-line balancing and bio-inspired optimization for manufacturing. The full methods, benchmarks, and results are in these papers.

Conference2025 · 2025 IEEE 15th International Conference on Control System, Computing and Engineering (ICCSCE)
Exploring Efficiency and Solution Diversity for Type-E Assembly Line Balancing Problem
Journal2021 · {IEEE} Access
Leveraging bio-inspired knowledge-intensive optimization algorithm in the assembly line balancing problem
Journal2021 · Flexible Services and Manufacturing Journal
Incorporating shifting bottleneck identification in assembly line balancing problem using an artificial immune system approach
Conference2020 · 2020 IEEE 16th International Conference on Control and Automation (ICCA)
An artificial immune system approach for solving type-e assembly line balancing problem with problem-specific information
Journal2018 · International Journal of Engineering and Technology (IJET)
An artificial immune system approach for type e assembly line balancing problem
Journal2016 · ICIC Express Letters
A survey on bio-inspired multi-agent system for versatile manufacturing assembly line

See also the crowd-evacuation simulation and the full demo gallery.