Optimal initialization of manipulation dynamics by vorticity model of robot hand preshaping. Part II: Analyses of grasp initialization and its vorticity based optimization

Our work focuses on developing methods of determining the optimal preshape of a robot hand closing onto an object in order to achieve at contact a certain stability and manipulability degree based on kinematic considerations. This purposive closing of a preshaped hand should then be kinematically modelled in such a way that impact force patterns on the object can naturally be deduced from the model and be optimized such that upon contacting the object the desired optimum initial conditions of manipulation are generated. We define in Part I of this two part article the stability and manipulability criteria of a robot hand preshape based on vertex theory dealing with the analysis of vorticities in the robot hand workspace. The grasp initialization patterns are generated as a forward stress problem using the finite element method. There, in Part II of the article they are further related to the concept of manipulability so that a robot hand grasping problem is formulated that maximizes manipulability and stability upon landing of fingertips onto the object. This problem is solved in Part II by finding the proper contact locations of fingertips for optimally impacting the object and properly initializing the manipulation phase