Robots handling a knife is not a complicated task. Teaching them to cut things with the right amount of force is another story though. Xiaoqian Mu, Yuechuan Xue, and Yan-Bin Jia from Iowa State University are teaching a robot how to use a knife to slice vegetables.
A 2DOF robotic arm with a force/torque sensor is used to perform press, push, and slice moves. A separate control strategy in Cartesian space is used for each move to account for contact and force constraints.