Development and application of new evolutionary algorithms and computer graphics tools for the design of multibody systems

In this dissertation new optimum design tools are proposed and tested for solving several difficult multibody design problems drawn from engineering practice.; Estimation of Distribution Algorithms (EDA) have been considered as optimization tools for their robustness and global optimum finding capabilities. EDA's are the latest newcomers to the growing family of Evolutionary Algorithms, and their potential for solving constrained optimization problems has been investigated in this dissertation for the first time.; Secondly a new method of visualizing multivariate functions is proposed where the dimension reduction is done by repeated partial global minimizations and maximizations. For objective functions in particular it allows studying constraint activity, performing parametric design studies, what-if scenario analysis, etc.; These tools were applied successfully to the solution of several multibody design problems: (1) Synthesis of the slider-crank and oscillating slide actuators for imposed output member displacement and maximum motion transmission efficiency. By systematically investigating their properties, design and performance charts were generated and new properties and possible applications identified (patent pending). (2) Determination of the optimum number of gear teeth of a multispeed automatic transmission that best fulfill imposed gear ratios, under the conditions of avoiding gear-teeth undercut, noninterference of neighboring gears and assembling equally spaced planets. (3) Synthesis of a five-link rear wheel suspension used in automobiles from the condition of simultaneously ensuring that the wheel base, wheel track, toe and camber angles have minimum variations while the wheel oscillates. Displacement, velocity, acceleration and roll-center height analyses were also performed in a new, simplified manner and improvements of the solutions obtained through synthesis over an existing design revealed. The analysis results were found to agree with those obtained using a commercially available multibody simulation software.; The above problems were solved with the goal of revealing general properties of the respective multibody systems and whenever possible, parameter charts and design recommendations have been advanced to aid the practicing engineer.