Fabio Ruggiero's website
An object is manipulated in a nonprehensile way when it is not caged between the fingertips or the hand's palm. Moreover, the so-called "force closure" constraint does not hold at each time of the manipulation task. This means that the motion can be performed also thanks to unilateral constraints: the part can thus roll, slide and break the contact with the robot manipulating it. Examples of everyday nonprehensile manipulation tasks are pushing objects, folding clothes, carrying a glass on a tray, cooking in a pan and so on. Nonprehnesile manipulation can be also referred to as dynamic when the dynamics of both the object and the robot are essential to accomplish the desired task. A common approach within the robotic community is to split a complex nonprehensile manipulation task in several subtask, that are more easy to deal with individually. Therefore, it is possible to define the so-called ``motion primitives'' like rolling (both holonomic and nonholonomic), throwing, bouncing, catching, sliding and so on. The main goal regarding Fabio Ruggiero's research is to design a common practical/theoretical framework where each motion primitive can be equipped with a proper motion planner and controller.
A holonomic rolling motion between two convex surfaces at contact is considered here and here. There are no constraints between the two surfaces but only the rolling one. In particular, the stabilization in full gravity of the unstable position of a disk free to roll on an actuated disk is addressed. The same set-up is considered here in presence of the so-called ``matched disturbances'' within the control action. The found solution exploits the port-Hamiltonian approach. By generalizing the method, here, under certain assumptions about the shapes of the rolling surfaces, a proper change of coordinates allows to study the general case of nonprehensile planar rolling through classic nonlinear control techinques, where the design of the controller is much simplified. A npnprehensile manipulation task in case of nonholonomic rolling can be considered the motion control of the `ballbot'', that is a spherical robot with a cylindrical top. A geometric control approach without coordinates is proposed here.
The bouncing motion primitive is examined here, where the table tennis case study is considered. A motion planner for the paddle, considering also its orientation, is introduced in the cited manuscript. The whole aerodynamic of the flying ball is taken into account without neglecting the real-time execution of the implemented algorithm. The throw of a deformable object is instead addressed here. The example of a pizza-maker who acrobatically throws the pizza in the air to stretch the dough is considered. The model and the control are designed by using a geometric approach without makin use of coordinates.