With 12 Partners involved, ASSISTANT aims to provide a set of AI-based intelligent digital twins that helps process engineers and production planners to operate collaborative mixed-model assembly lines based on the data collected from IoT devices and external data sources. Such a tool will help planners to design the assembly line, plan the production, operate the line, and improve process tuning. In addition, the system monitors the line in real-time, ensures that all required resources are available, and allow fast re-planning when necessary. ASSISTANT aims to make cost-effective decisions while ensuring product quality, safety, the well-being of the workers, and managing the various sources of uncertainties. The resulting intelligent digital twin systems will be data-driven, agile, autonomous, collaborative, explainable, and safe but reactive.