Parameter optimization of heavy-load parallel manipulator by introducing stiffness distribution evaluation index

Abstract

Aiming at the heavy-load parallel robotic manipulators, other than classic sequential ‘topology-dimension-structure’ parameter design methodology, this paper proposes a new way to optimize dimension and structure parameters11Just to be clear, in most cases, dimensional parameters normally indicate length of linkages, and structural parameters involves sectional area parameter of both linkage and moving platform. simultaneously. To deal with the low-speed but heavy load working environment, a new type of stiffness performance evaluation index is introduced based on kineto-elastic statics (KES) analysis. This stiffness distribution index, mainly focuses on the stiffness distribution among all parts in the manipulator, along with two other dynamic performance indices and some dimensional constraints, formulate a multi-objective optimization model. Then the particle swarm optimization (PSO) algorithm is introduced to search for the optimum parameters. This method is applied on a widely used TRICEPT parallel manipulator, the dynamic performances before and after optimization are compared to verify this effectiveness of this method.