In this thesis we are going to study the energy shaping problem on controlled Lagrangian systems with degree of underactuation less than or equal to two. Energy shaping is a method of stabilization by designing a suitable feedback control force on the given controlled Lagrangian system so that the total energy of the feedback equivalent system has a non-degenerate minimum at the equilibrium. Th...

A geometric formulation for stabilization of systems with one degree of underactuation which fully solves the energy shaping problem for these system is given. The results show that any linearly controllable simple mechanical system with one degree of underactuation is stabilizable by energy shaping, even in the absence of gyroscopic force, via a closed-loop metric which is not necessarily posi...

Low-Dimensional Robotic Grasping: Eigengrasp Subspaces and Optimized Underactuation

The main focus of this paper is on the motion planning problem for an under-actuated, submerged, omni-directional autonomous vehicle. Underactuation is extremely important to consider in ocean research and exploration. Battery failure, actuator malfunction and electronic shorts are a few reasons that may cause the vehicle to loose direct control of one or more degrees-of-freedom. Underactuation...

Force rendering is important in underactuated haptic systems. Underactuation means that some force directions at the contacts cannot be rendered because of the lack of actuation. In this paper we propose to exploit the knowledge of the task to mitigate the effect of the underactuation. The simulation of a grasp is considered and two alternative algorithms are proposed to improve the sensitivity...

Underactuation in robotic hands is currently attracting a lot of interest from researchers. The challenging idea of underactuation in grasping is that hands, with reduced number of actuators, supported by suitable design and control, may not suffer from reduced performances. This trend is also strengthened by recent neuroscience studies which demonstrates that also humans use sensorimotor syner...

Abstract The R-Min robot is an intrinsically safe parallel manipulator dedicated to pick-and-place operations. proposed architecture based on a five-bar mechanism, with additional passive joints in order obtain planar seven-bar mechanism two degrees of underactuation, allowing the reconfigure case collision. A preload bar added between base and end-effector constrain degrees-of-freedom. This ar...

In this paper, a methodology is proposed for the analysis of the force capabilities of connected differential mechanisms. These systems are the key elements used to extend the principle of underactuation in grasping from the fingers to the hand itself. The concept of underactuation in robotic grasping— with fewer actuators than degrees of freedom (DOF)—allows the hand to adjust itself to an irr...