Manipulation of deformable objects without modeling and simulating deformation

Abstract

We present a method to manipulate deformable objects that does not require modeling and simulating deformation. Our method is based on the concept of diminishing rigidity, which we use to quickly compute an approximation to the Jacobian of the deformable object. This Jacobian is used to drive the points within the deformable object towards a set of targets. However, this Jacobian alone is insufficient to avoid stretching the object beyond its allowed length and to avoid gripper collision with obstacles. Thus a key part of our approach is incorporating techniques to avoid collision and excessive stretching. Our experiments show how to perform several interesting tasks for one and two-dimensional deformable objects using our method. They also show how the method can be applied to collaborative tasks, where the robot and a user simultaneously manipulate the deformable object. Our experiments are conducted in simulation but we emphasize that our method does not have access to the model of the deformable object used by the simulator, although we assume we are able to sense the geometry of the object. While our method is local, we find that it is quite versatile in the range of tasks it can perform, especially since it has no knowledge of the model of the deformable object.