Kinematics of continuum planar grasping
For researchers in soft robotics, this provides a theoretical foundation for continuum arm grasping, but the work is incremental as it extends existing kinematic and optimal control methods to a specific geometry.
This paper develops an analytical framework for continuum planar grasping, modeling the arm and object as smooth curves and formulating grasping as a kinematic boundary following problem. It derives reduced kinematic equations, solves an optimal control problem for feasible arm shapes, and proposes grasp quality metrics, validated through simulations.
This paper presents an analytical framework to study the geometry arising when a soft continuum arm grasps a planar object. Both the arm centerline and the object boundary are modeled as smooth curves. The grasping problem is formulated as a kinematic boundary following problem, in which the object boundary acts as the arm's 'shadow curve'. This formulation leads to a set of reduced kinematic equations expressed in terms of relative geometric shape variables, with the arm curvature serving as the control input. An optimal control problem is formulated to determine feasible arm shapes that achieve optimal grasping configurations, and its solution is obtained using Pontryagin's Maximum Principle. Based on the resulting optimal grasp kinematics, a class of continuum grasp quality metrics is proposed using the algebraic properties of the associated continuum grasp map. Feedback control aspects in the dynamic setting are also discussed. The proposed methodology is illustrated through systematic numerical simulations.