Indirect Manipulation of a Sphere on a Flat Disk Using Force Information

The objective of this study is to verify if only the use of robotic force feedback enables indirect and dynamic manipulations which are difficult for human beings to perform. Human beings usually control the trajectory of an object using visual feedback; force/tactile information are secondarily employed because they are further qualitative in comparison with visual information. However, it is supposed that robots have the potential to perform such the tasks without visual information because force/tactile information can be also used quantitatively in the control system. This paper especially focuses on an indirect manipulation of a sphere on a flat plate realized by employing only force information. In this paper, we propose a very simple method to estimate the position of the sphere on the plate which is put on a multi-fingered robot and try to control the trajectory by changing the fingertip heights based on the error between the desired and estimated positions. We also analyze the stability of the proposed control system with an approximate Lyapunov's stability criterion. Finally, this paper shows very attractive robotic demonstrations based on the proposed method.