Mención Europea en el título de doctorThis thesis presents methods and tools for enabling the successful use of
robotic hands. For highly dexterous and/or anthropomorphic robotic hands,
these methods have to share some common goals, such as overcoming the
potential complexity of the mechanical design and the ability of performing
accurate tasks with low and efficient computational cost.
A prerequisite for dexterity is to increase the workspace of the robotic hand.
For this purpose, the robotic hand must be considered as a single multibody
system. Solving the inverse kinematics problem of the whole robotic hand is
an arduous task due to the high number of degrees of freedom involved and
the possible mechanical limitations, singularities and other possible constraints.
The redundancy has proven to be of a great usefulness for dealing
with potential constraints. To be able to exploit the redundancy for dealing
with constraints, the adopted method for solving the inverse kinematics
must be robust and extendable. Obviously, addressing such complex problem,
the method will certainly be computationally heavy. Thus, one of the
aims of this thesis is to resolve the inverse kinematics problem of the whole
robotic hand under constraints, taking into account the computational cost.
To this end, this thesis extends and reduces the most recent Selectively
Damped Least Squares method which is based on the computation of all
singular values, to deal with constraints with a minimum computational
cost. New estimation algorithm of singular values and their corresponding
singular vectors is proposed to reduce the computational cost. The reduced
extended selectively damped least squares method is simulated and experimentally
evaluated using an anthropomorphic robotic hand as a test bed.
On the other hand, dexterity depends not only on the accuracy of the position
control, but also on the exerted forces. The tendon driven modern robotic hands, like the one used in this work, are strongly nonlinear dynamic
systems, where motions and forces are transmitted remotely to the
finger joints. The problem of modeling and control of position and force
simultaneously at low level control is then considered. A new hybrid control
structure based on the succession of two sliding mode controllers is
proposed. The force is controlled by its own controller which does not need
a contact model. The performance of the proposed controller is evaluated
by performing the force control directly using the force sensor information
of the fingertip, and indirectly using the torque control of the actuator.
Finally, we expect that the applications of the methods presented in this
thesis can be extended to cover different issues and research fields and in
particular they can be used in a variety of algorithm that require the estimation
of singular values.This work was partially supported by the European project HANDLE, FP7-231640, and by the Spanish ministry MICINN through FPI scholarship within the project DPI-2005-04302.Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y AutomáticaPresidente: Anis Sahbani.- Secretario: Fares Jawad Moh D Abu-Dakka.- Vocal: Claudio Ross
