Design of a decoupled compliant parallel manipulator for bidimensional translations

This work aims at developing a compliant parallel manipulator capable of performing bi-dimensional decoupled translation. Achieving decoupled motion with a compliant robot is inherently challenging due to the nature of compliant mechanisms themselves, relying on flexibility, and condensing the number of parts. Whereas there exist already planar compliant parallel mechanisms performing decoupled planar translations, most of them implement complex compliant versions of prismatic joints and a stage-based structure, leading to increased difficulty of assembly. The performances of spatial compliant parallel robots operating the bi-dimensional translational task have not been yet explored. First, this work provides an introduction to parallel and serial robots. Then, it proceeds with a lead-in about compliant mechanisms, whose benefits and challenges are described, and some examples are provided. After a brief state of the art about compliant decoupled parallel manipulators, the focus shifts to the synthesis methods for rigid-body decoupled parallel mechanisms. Some of the illustrated methods require optimization techniques, and some the application of powerful mathematical instruments. A method is then adopted and applied for the synthesis of the decoupled parallel manipulators. Once the synthesis of the mechanism is completed, we proceed with analyzing the kinematics of the decoupled parallel manipulator and proving its decoupled nature by writing a system of equations based on the geometric constraints of the distal section of each limb. The design process of the rigid-body decoupled parallel manipulator and the stages for the design of its compliant counterpart are then developed. Some considerations are made on the basis of the adopted manufacturing method and some design choices that had to adapt to it are delineated and reasoned. In addition, an overview of the chosen manufacturing technique is given. In the end, the conclusions of the present work are provided.