Problem statement: Underactuated finger mechanism is beneficial in the anthropomorphic applications in which it reduces the finger size, weight and power consumption due to the less number of actuators compared to its number of Degree Of Freedom (DOF). However, the currently existing underactuated finger is limited to grasping operations only and unable to pinch with the finger tip. Moreover, t...

In this paper we propose a Fractional Order Controller for an under-actuated system (POAC). This system has two degrees-of-freedom and one control input. The model of the system is derived using Euler Lagrange method and the stabilization is achieved with constraints using Fractional Order Controller. To validate the control law, simulation are performed and compared with Integer Order Controll...

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...

A manoeuvring model and a design technique for path following applications of underactuated underwater vehicles are summarized. The model applies to slender body autonomous underwater vehicles (AUV) of cylindrical shape employing similar types of steering and diving control surfaces, and is meant for low speed manoeuvring applications. The underactuated design procedure used to successfully sol...

As the extension of traditional linear (or X) inverted pendulum (IP), X-Z IP is a multiple-input multiple-output (MIMO), underactuated, open-loop unstable, and nonlinear system. In tracking control IP, equilibrium point changes with pivot position pendulum. This makes theories have difficulties in realization for The underactuated feature feedback linearization unsuitable to simplify design. Wi...

In the last decade, energy based control theory has undergone a significant breakthrough in dealing with underactated mechanical systems with two successful and similar tools, controlled Lagrangians and controlled Hamiltanians (IDA-PBC). However, because of the complexity of these tools, successful case studies are lacking, in particular, MIMO cases. The seminal theoretical paper of controlled ...

This paper addresses the problem of dynamic positioning and way-point tracking of underactuated autonomous underwater vehicles (AUVs) in the presence of constant unknown ocean currents and parametric modeling uncertainty. A nonlinear adaptive controller is proposed that steers an AUV along a sequence of way-points consisting of desired positions (x, y) in a inertial reference frame, followed by...

Inspired by the previous work of Aicardi et al.[1] a path following controller for underactuated planar vehicles is designed by adopting a polar-like kinematic model of the system. The solution proposed does not generally guarantee null asymptotic path following error, but only its boundedness below an adjustable upper threshold. However, knowledge of the path curvature is not necessary, thus r...

A new method for motion planning and trajectory tracking of underactuated three-link planar robots with a passive rotational third joint is proposed. One fundamental feather is to use the switching of partly stable controllers (PACs) in order to fulfill the control objective. The dynamic model of this kind of underactuated robot system is built based on Lagrange method. Different objective func...

A nonlinear, closed-loop, time-invariant controller that globally stabilizes an underactuated marine vehicle on a straight course is proposed. Traditional surface vessel linear course tracking autopilots are designed applying linear control methods on the linearized model, thus yielding only local results. Indeed due to the underactuated nature of the system, the model cannot be feedback linear...