Design and simulation based validation of the control architecture of a stacker crane based on an innovative wire-driven robot

Automated Storage/Retrieval Systems (AS/RS) have an important role in the improvement of the performance of automated manufacturing systems, warehouses and distribution centers. Existing AS/R systems are usually based on Cartesian Storage/Retrieval Manipulators (SRM). Such systems have reached their maximum performance due to the limitations of their underlying mechanical design and associated control architecture. Going beyond the limits of existing systems requires structural innovation and breakthrough solutions to enhance their design and performance. In this study, we introduce the design and simulation based evaluation of a stacker crane based on an innovative wire-driven SRM. We describe the basic components and provide an overview of the mechanical design of the system. We design the high-level control architecture that allows handling mini-load operations. We develop the equations that determine the single and dual command cycle times for the wire-driven SRM in case of random and class-based storage policies. We validate the suggested control architecture using a simulation software specifically developed for this purpose. We benchmark the wire-driven SRM against an equivalent Cartesian SRM. Results show that the new wire-driven SRM design and control architecture are more competitive than Cartesian SRM in terms of travel cycle times, and more suitable for buildings growing in height.