Soft finger rotational stability for precision grasps

Soft robotic fingers can safely grasp fragile or variable form objects, but their force capacity is limited, especially with less contact area: precision grasps and when objects are smaller or not spherical. Although most research focuses on improving force capacity through mechanical design modifications, optimizing grasping parameters for precision tasks remains crucial. To address this problem, this paper proposes an analytical rotational stability model for soft fingers’ precision grasping, considering grip failure involving slip and dynamic rotational stability. Comprehensive experiments across various objects, grip condition and types of fingers (PneuNet and commercial fingers) are conducted by examining the relationship between grasp parameters and model variables including coulomb friction, bulk stiffness, and dynamic stability. The findings demonstrate the model’s utility in identifying optimal grip parameters that enhance the force capacity of soft fingers without causing dynamic instability. This research contributes to the development of more effective and stable soft robotic fingers for precision grasping tasks.