Robotic Cutting of Solids Based on Fracture Mechanics and FEM Cutting skills are important for robots to acquire not only because of a need from kitchen automation, but also because of the technical challenge for robotic manipulation. Modeling of fracture and deformation during a cutting action, often based on the finite element method (FEM), provides the force and shape information used in knife control to implement a skill such as slice, chop, or dice. However, an objectxe2x80x99s 3D mesh model can be computationally prohibitive for achieving a desired accuracy since numerous tiny elements must be used near the knifexe2x80x99s moving edge. To address this issue, we represent the object as evenly spaced slices normal to the cutting plane such that cutting of each slice requires only a 2D mesh. Fracture and force can be then interpolated between every two adjacent slices. Experiment with an Adept arm and an ATI forcetorque (FT) sensor has demonstrated reasonable accuracy in force ad shape modeling.

ForceandMotion Constrained Planning for Tool Use The use of hand tools presents a challenge for robot manipulation in part because it calls for motions requiring continuous force application over a whole trajectory, usually involving large jointangle excursions. The feasible application of a tool, such as pulling a nail with a hammer claw, requires careful coordination of the choice of grasp and joint trajectories to ensure kinematic and force limits are not exceeded  in the grasp as well as the robot mechanism. In this paper, we formulate this type of problem as choosing the values of decision variables in the presence of various constraints. We evaluate the impact of the various constraints in some representative instances of tool use. To aid others in further investigating this class of problems, we have released materials such as printable tool models and experimental data. We hope that these can serve as the basis of a benchmark problem for investigating tasks that involve many kinematic, actuation, friction, and environment constraints.