An adapted NSGA-II approach to the optimization design of oil circuits in a hydraulic manifold block

ABSTRACT:   The optimization design of oil circuits in a Hydraulic Manifold Block (HMB) is a typical Multiobjective Optimization Problem (MOP), and typical optimization objectives include the number of cross-drills, the depth of working holes and cross-drills, and the length of oil circuits. MOP for HMB design is usually converted to a Single-objective Optimization Problem (SOP) by weighting method; however, the validity is not guaranteed. In this paper, maze algorithm—NSGA-II optimization method (MA-NSGA-II) is presented as improve NSGA-II. In this approach, a coordinate bunch format is proposed to encode the oil circuit parameters and the oil circuit connection; then, the maze algorithm is used to generate the initial population; further new operators of crossover and mutation are introduced and applied to adapt classical NSGA-II to suit the proposed encoding format. On the basis of this approach, an optimization design system for HMB is developed by using SolidWorks Application Programming Interface (API), VB.NET, and Microsoft Access. The system effectively realizes the automatic generation and optimization of oil circuits. A case study is conducted to verify the validity of the approach and the system.