General methodology for multi-objective optimal design of control-structure nonlinear mechanisms with symbolic computing

Abstract

<p>An integrated approach for designing nonlinear planar controlled mechanisms for performance, sensitivity, variability, and manufacturability is presented. The nonlinear programming approach combines the dynamic and sensitivity formulations to be evaluated in parallel, so that through optimization, the design space is thoroughly explored. The multi-objective optimization allows the user to design for many different criteria, mentioned above. Lagrangian dynamics are first used to synthesize a double slider mechanism. Second, the same double slider mechanism is synthesized using a multibody constrained formulation. The multibody constrained formulation will allow for symbolic generation of dynamic and sensitivity equations with ease. This formulation will also allow for a generalized approach for implementing a controller of any order. This general implementation allows for a truly integrated design approach, any variable in the formulation can be a design variable, whether it is part of the structure, or the controller. A symbolic package can then be used for generating equations, and the integration will be done numerically. The results presented will be an initial design, and the optimized design at each of four optimization criteria for a double slider mechanism. The same method will be applied to a construction loader linkage to show that this method will work on real life problems of a large scale and complexity. It will be clearly presented that sensitivity based design and optimization allows a designer to get more robust performance using looser tolerances, than previous methods suggest. Additionally, more useful information about the entire design space is known as the design is developed.</p>