Optimization models for flexible manipulators.

Abstract

The need for reducing manufacturing costs has recently stimulated research efforts in the area of flexible manipulator design. Flexible manipulators are lightweight and have a much larger speed range than heavier rigid-link manipulators; hence, their use greatly improves productivity while reducing energy consumption. But, due to their inherent flexibility, undesirable tip oscillations are encountered in normal operation. An important direction in flexible link research is the search for structural designs which either minimize the mass or maximize the speed, while at the same time limit tip oscillations. These two basic design problems are solved using two different models, both based on the link's fundamental frequency of vibration. An analytic model is developed as a theoretical basis of optimum link design. The resulting optimality equations are solved using an iterative method. In order to accommodate various constraints on link design, an optimization model is developed which uses mathematical programming methods to solve the segmentized formulation. The requirement of multiple tip loads is cast into a minimax optimum design model. Also, a multi-link optimum design model is developed which utilizes single-link solutions. Various geometrical constraints are integrated into the optimization model, allowing conformity to requirements of specialized applications. Composite material designs are considered due to their growing demand in high-speed lightweight applications. Finally, a sensitivity analysis of design parameters is conducted to reveal the robustness of optimum designs.