Parametric Dimension Synthesis and Optimizations of Planar 5R Parallel Robots

The dimension synthesis problem for parallel robots in general is much more complex than their serial counterparts, due to the strong dependence of geometric parameters and their performances. In dimension synthesis for robots, typical performance characteristics that may be considered to evaluate the fitness of a design include workspace, manipulability, velocity, stiffness, and payload. A case study on optimal design for both workspace and manipulability had been presented previously for a class of planar parallel robots with 5R joints. This paper extends the design optimization study to include stiffness, velocity, and payload characteristics for the same class of 2-dof robots. A simple and effective parameter-variation-based, constrained optimization method will be demonstrated to obtain various optimal design solutions corresponding to those characteristics respectively. The optimal design solutions, obtained in scalable dimensionless forms, are global in nature and relative to a workspace constraint.