Reactive robotics I: Reactive grasping with a modified gripper and multifingered hands

We study the problem of grasping an unknown object with constant cross sect ion using various "reactive" robot hands. In the simplest example, we equip a standard parallel-jaw gripper with several light-beam sensors (close to each jaw) and implement a reactive algorithm for grasping polygonal objects with this architecture. Extending these ideas further; we also devise two- and three-fingered reactive hands for objects with smooth boundary and equ ip these with distance and angle sensors that are located at the finger tip s. The sensors used are simple and provide only limited and immediate infor mation, but they allow us to reactively find a good grasp on an object of u nknown geometry and dynamics. When grasped, the forces applied will be norm al to the object boundary. Furthermore, in all cases, the object is not dis turbed as the grasping points are being sought.