Digital twin-enabled Graduation Intelligent Manufacturing System for fixed-position assembly islands

•Designed a Graduation-inspired assembly system for fixed-position layout.•Unified digital representations with appropriate sets of information at object, product and system level are developed.•IoT-enabled solutions are proposed to achieve real-time synchronization between physical space and digital space.•Developed cloud-based services with real-time ticket pool management mechanisms for facilitating decision-making and daily operations.