Robotic Manipulation for Identification of Flexible Objects

This paper provides preliminary insight into stiffness profile identification of a complex flexible object by robotic manipulation. The object is in the shape of the letter 'Y', chosen to resemble a living plant. The object is approximately modelled as a spring mass system. The robot manipulates the object with one or two arms grasped at the ends of the 'Y', and makes visual measurements which locates the object's position in space. Identification results from an optimization approach are compared for both one and two arm manipulation and sensing with and without vision. The results are not consistent with the expected physical object's properties due to a failure to observe the motion dependence between the object's connected segments. The result provides insight into the problem of assessing the minimal information needed to identify the stiffness of a flexible object, an issue of importance to automated approaches.