| Abstract [eng] |
In the modern logistics centres, the qualitative and quantitative requirements for the load processing are constantly increasing and significantly influence the order picking process – the most complex and important process in the warehouse, which requires 55% of the total management costs. The order picking systems require continuous improvement and it was proposed to use the automated transportation systems to increase their performance. Automated systems allow to change the product flow direction in the warehouse by applying “Goods To Person” type systems, where the product loads are automatically transported from the storage to the order picking stations. Despite many advantages of such systems, they lack flexibility and have various limitations, which have a negative impact on their performance and require structure and control design improvements. A new concept of automated cylindrical storage and retrieval system (C-AS/RS) is proposed in this research, which improves the automated transportation system and increases the performance of the automated “Goods to Person” order picking system. The C-AS/RS structure, control algorithms, performance measures and integration methodology into automated transportation systems were developed together with analysis models, which allow to evaluate system performance and identify optimal parameter values. The analysis models were used to evaluate dependencies of the improved automated transportation system performance measures on the structure and control parameters and the impact of C-AS/RS integration into automated “Goods to Person” order picking system. The dissertation is comprised of introduction, four chapters, general conclusions, bibliography, author‘s scientific publications and annexes. The first chapter focuses on the analysis of the main warehouse processes, reviews the automated transportation systems in logistics centres and identifies their weaknesses and integration problems into automated “Goods to Person” order picking systems. The second chapter describes and supplements the design methodology of standard automated storage and retrieval systems (AS/RS), identifies the load sequencing problems and proposes the AS/RS integration guidelines into automated “Goods to Person” order picking systems. In addition, analytical and simulation analysis models were compared and the integrated analysis methodology was developed, which is based on simulation and advanced statistical analysis methods. The third chapter describes the concept and control algorithms of the proposed C-AS/RS including its integration principles for the automated “Goods to Person” order picking system. The parametrized simulation model of C-AS/RS was also described, which allows to investigate system performance with selected structure parameters, control algorithms and load flow rates. The fourth chapter provides the C-AS/RS analysis results and identifies the most significant factors affecting the C-AS/RS performance, which allow to provide a complex system evaluation and compare different configurations. The relationships between C-AS/RS performance measures and various system parameters were also evaluated and multiple regression models were developed. The major results of this research were published in two articles in reviewed periodic scientific journal. |
