Stable Bipedal Locomotion Using Biomimetic IPMC Actuators

Ionic conducting polymer-metal composites (abbreviated as IPMC) are interesting actuators that can act as artificial muscles in robotic and microelectromechanical systems. The electrochemical-mechanical behavior of these materials has been modeled by various black or gray box models. In this study, the governing partial differential equation of the behavior of IPMC is solved using finite element methods to find the critical actuation parameters such as strain distribution, maximum strain, and response time. 1D results of the FEM solution are then extended to 2D to find the tip displacement of a flap actuator. Model of a seven-degree of freedom biped robot, actuated by IPMC flaps, is then introduced to study. Possibility of fast and stable bipedal locomotion using IPMC artificial muscles is the main motivation of this study. Taking the actuator limits into account, joint path trajectories are generated to achieve a fast and smooth motion. The stability of the proposed gait is then evaluated using ZMP criterion and motion simulation. Fabrication parameters of each actuator such as length, platinum (or gold) plating thickness and installation angle are also studied using the generated trajectories.