Abstract
The aim of this work is to investigate alternative designs for machines intended for biomimetic locomotion in liquid environments. For this, structural compliance instead of discrete assemblies is used to achieve desired mechanism kinematics. We propose two models that describe the dynamics of special compliant mechanisms that can be used to achieve biomimetic locomotion in liquid environments. In addition, we describe the use of analytical solutions for mechanism design. Prototypes that implement the proposed compliant mechanisms are presented and their performance is measured by comparing their kinematic behavior and ultimate locomotion performance with the ones of real fish. This study shows that simpler, more robust mechanisms, as the ones described in this paper, can display comparable performance to existing designs.