Mechanical Optimization Design and Automation Application Based on Machine Vision Technology

The application of related tech represented by machine vision in mechanical design has gradually deepened, which has greatly ameliorated the automation of mechanical design. Based on this, this paper first analyses the principle and important composition of machine vision tech, then studies the utilization value of machine vision tech in mechanical design, and finally analyses the typical practical utilization of machine vision tech in workpiece detection, workpiece measurement and high-precision measurement in mechanical design.

Hybrid inner-outer algorithm for solving real-world mechanical optimization problems

In the real world, the problems mostly are complex; more precisely, the problems generally are nonlinear or large scale other than if it was mandatory to resolve it under certain constraints, and that is common in engineering design problems. Therefore, the complexity of problem plays a critical role in determining the computational time and cost. Accordingly, a novel algorithm called inner-outer array is proposed in this paper. It depends on the design of parameters and then tolerance design as one of design of experiment stages. In this work, the inner-outer algorithm is used to solve real-world optimization problems to choose the preferable feasible regions of the entire search domain. Numerical results are documented and compared based on four well-known constrained mechanical engineering issues. It can be concluded that the performance of inner-outer algorithm is good to optimize constrained engineering problems, but it still needs some enhancements in the future work.

Research on mechanical optimization methods of cable-driven lower limb rehabilitation robot

In order to improve the working performance of the lower limb rehabilitation robot and the safety of the trained object, the mechanical characteristics of a cable-driven lower limb rehabilitation robot (CDLR) are studied. The dynamic model of the designed CDLR was established. Four kinds of cable tension optimization algorithms were proposed to obtain a good rehabilitation training effect, and the quality of the feasible workspace of the CDLR was analyzed. Finally, a real-time evaluation index of the cable tension optimization algorithms was given to measure the calculation speed of the optimization algorithms. The numerical research results were provided to confirm the characteristics of the four kinds of the optimization algorithms. The research results provide a basis for the follow-up research on the safety and compliance control strategy of the CDLR system.

Impeller Optimization in Crossflow Hydraulic Turbines

Crossflow turbines represent a valuable choice for energy recovery in aqueducts, due to their constructive simplicity and good efficiency under variable head jump conditions. Several experimental and numerical studies concerning the optimal design of crossflow hydraulic turbines have already been proposed, but all of them assume that structural safety is fully compatible with the sought after geometry. We show first, with reference to a specific study case, that the geometry of the most efficient impeller would lead shortly, using blades with a traditional circular profile made with standard material, to their mechanical failure. A methodology for fully coupled fluid dynamic and mechanical optimization of the blade cross-section is then proposed. The methodology assumes a linear variation of the curvature of the blade external surface, along with an iterative use of two-dimensional (2D) computational fluid dynamic (CFD) and 3D structural finite element method (FEM) simulations. The proposed methodology was applied to the design of a power recovery system (PRS) turbine already installed in an operating water transport network and was finally validated with a fully 3D CFD simulation coupled with a 3D FEM structural analysis of the entire impeller.

Behavior of a Variable Geometry Turbine Wheel to High Cycle Fatigue

Maximization of the turbocharger efficiency is fundamental to the reduction of the internal combustion engine back-pressure. Specifically, in turbochargers with a variable geometry turbine (VGT), energy losses can be induced by the aerodynamic profile of both the nozzle vanes and the turbine blades. Although appropriate considerations on material limits and structural performance of the turbine wheel are monitored in the design and aero-mechanical optimization phases, in these stages, fatigue phenomena might be ignored. Fatigue occurrence in VGT wheels can be categorized into low and high cycle behaviors. The former would be induced by the change in turbine rotational speed in time, while the latter would be caused by the interaction between the aerodynamic excitation and blades resonating modes. In this paper, an optimized turbine stage, including unique nozzle vanes design and turbine blades profile, has been assessed for high cycle fatigue (HCF) behavior. To estimate the robustness of the turbine wheel under several powertrain operations, a procedure to evaluate HCF behavior has been developed. Specifically, the HCF procedure tries to identify the possible resonances between the turbine blades frequency of vibrations and the excitation order induced by the number of variable vanes. Moreover, the method evaluates the turbine design robustness by checking the stress levels in the component against the limits imposed by the Goodman law of the material selected for the turbine wheel. In conclusion, both the VGT design and the HCF approach are experimentally assessed.