This paper investigates the in-hand manipulation capabilities of a compliant, underactuated planar robotic hand by treating the system as a simple, symmetric, 6-bar linkage mechanism with compliant joints. Although underactuated hands are generally not considered to be adept at dexterous tasks, we have found through past work that an underactuated manipulator can control n degrees of freedom wi...

ivThe class of underactuated systems is composed of a variety of mechanical as well asbiological systems. The term underactuation refers to the fact that not all joints or degrees-of-freedom (DOFs) of the system are equipped with actuators, or are directly controllable.The DOFs of an underactuated system are dynamically coupled, and their dynamicequations are nonlinear and a...

The property of form-closure of a grasp, as generally defined in the literature, is based on the assumption that contact points between the hand and the object are fixed in space. However, this assumption is false when considering a grasp exerted by an underactuated hand, since in this case, it is not possible to control the position of each phalanx independently. In spite of researchers’ inter...

In this paper, we address nonlinear control and reduction of a class of high-order underactuated mechanical systems with kinetic symmetry called Class-I systems. Class-I systems are underactuated systems with actuated shape variables, decoupled inputs, and integrable normalized momentums (all to be de ned). We show that all Class-I underactuated systems can be transformed into cascade systems i...

This paper studies control properties of the dynamics of underactuated vehicles (e.g. underactuated surface vessels, underwater vehicles, aeroplanes or spacecraft). The unactuated dynamics implies constraints on the accelerations. Both the necessary and suucient conditions for these constraints to be second-order nonholonomic, rst-order nonholonomic or holonomic are developed. It is shown that ...

There are many interesting mathematical problems in control theory. In this paper we will discuss problems and techniques related to underactuated systems. An underactuated system is one with fewer control inputs than degrees of freedom. Balancing a ruler on the tip of a finger is a good example of an underactuated system. This system has five degrees of freedom (three for the fingertip and two...

Underactuated manipulators are robot manipulators composed of both active and passive joints in serial chain mechanisms. The study of underactuation is significant for the control of a variety of rigid-body systems, such as free-floating robots in space and gymnasts, whose structure include passive joints. For mechanisms with large degrees of freedom, such as hyper-redundant snake-like robots a...

There is a lack of agreement in the literature as to what exactly quantifies the performance of underactuated hands. This paper proposes two benchmark tests to measure the ability of underactuated hands to grasp different objects and the ability to hold the objects when force disturbances apply. The first test determines the smallest and largest cylindrical object which can be successfully gras...

This paper introduces a new concept for designing a fuzzy logic based switching controller in order to control underactuated manipulators. The proposed controller employs elemental controllers, which are designed in advance. Parameters of both antecedent and consequent parts of a fuzzy indexer are optimized by using evolutionary computation, which is performed off-line. Design parameters of the...

The robotic hands can be divided into two major groups: fully-actuated and underactuated hands. In fully-actuated hands all the joints have separate motors, while in underactuated hands the number of motors is less than number of degrees of freedom. The underactuated hands can adapt to the object shape by use of their mechanical design while they have less functionality. A relationship between ...