This paper describes a new concept in underactuated hand design, motivated by a study of parallel mechanisms. Inspired by the end-effector motion and system reconfiguration in parallel wrists, we propose a morphology of fingers such that during fingertip precision manipulation the instantaneous screw axes, which describe the displacement of the grasped object respect to the palm of the hand, al...

In this note we investigate open-loop control of underactuated mechanical systems and draw connections between averaging and controllability theory. Two sets of results are presented: averaging under high-amplitude high-frequency forcing, and series expansions for the evolution of a forced mechanical system starting at rest.

Control of underactuated mechanical systems (robots) represents an important class of control problem. In this correspondence, a model-based adaptive variable structure control scheme is introduced, where the uncertainty bounds only depend on the inertia parameters of the system. Global asymptotic stability is established in the Lyapunov sense. Numerical simulations are conducted to validate th...

This paper concerns the global stabilization of an underactuated spring-coupled three-link horizontal manipulator (STHM), which is an underactuated mechanical system (UMS) with two actuators and three degrees of freedom (DOF). A new control method is developed that asymptotically stabilizes the STHM at the origin using the position measurements of the manipulator only. First, we introduce a hom...

In this study, a robotic fish inspired to carangiform swimmers has been developed. The artifact presents new transmission system that employs the magnetic field interaction of permanent magnets ensure waterproofness and prevention from any overload for structure actuating motor. This mechanism converts rotary motion motor into oscillatory motion. Such an oscillating system, along with wire-driv...

A new sensor based homing integrated guidance and control law is presented to drive an underactuated autonomous underwater vehicle (AUV) towards a fixed target, in the horizontal plane, using the information provided by an Ultra-Short Base Line (USBL) positioning system. Almost global asymptotic stability (AGAS) is achieved, both in the absence of external disturbances and in the presence of co...

In this work we address the problem of nonlinear output regulation of an underactuated system by means of discontinuous control actions, in particular, the sliding mode output regulator problem in the case of error feedback is considered for the Pendubot system. The theory is revisited for nonlinear systems presented in the so-called Regular form. Simulations are carried out to verify the effec...

The single wheel, gyroscopically stabilized robot Gyrover, is a dynamically stable but statically unstable, underactuated system. In this paper, based on the dynamic model of the robot, we investigate two classes of nonholonomic constraints associated with the system. Then, based on the backstepping technology, we propose a control law for balance control of Gyrover. Next, through transferring ...