Analysis of the influence of parameters change on effective grasping force of an underactuated robotic hand

摘要

In order to achieve the grasping mission in deep space, a novel and highly underactuated robotic hand which composed of bars and tendons, is proposed. The hand contains two fingers, and each finger has three joints controlled by a single motor during the grasping process. To describe the structure and the grasping properties of the of tendon-bar robotic hand, one finger is taken as research object and the corresponding grasping model is established. To analysis the grasping characteristics, some effective methods such as creating the joint coordinate system, deriving the equilibrium equations with Jacobi matrix, analyzing the correlation between grasping force and tendon tension force, and plotting the grasping force influenced by different parameters, are illustrated. Through the model-based analysis, not only effective grasping force but also the static forces on every segment of the finger is derived. The variable parameters which impact significantly on the grasping force are analyzed, and the influence of the friction on the grasping force is analyzed in detail in this paper. Configuring the friction between the object and hand significantly improve the distribution of the grasping forces on segments, and significantly increase the effective grasping force.