Reaching to Grasp and Preshaping of Multi-DOFs Robotic Hand-Arm Systems Using Approximate Configuration of Objects

Object manipulation involves two tasks: 1) reaching to grasp and 2) grasping. Motivated by physiological studies related to first task, reaching to grasp, and a simple control method composed of joint-damping and a single virtual spring, we try out for realization of continuous reaching-to-preshaping movements by robotic hand-arm systems with a pair of 2DOFs fingers and a 3DOFs arm. Differently from conventional researches, this paper treats neither trajectories planning nor inverse kinematics. Instead of those, a few transit point and desired point in task-space and a control method with Jacobian transpose and joint velocity damping are merely adopted. Based on results of numerical computer simulation, it is concluded that it is possible to simply realize continuous robotic reaching-to-preshaping motion by adopting the transit points and the control method