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Dive into the research topics where Rodolfo García-Rodríguez is active.

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Featured researches published by Rodolfo García-Rodríguez.


Applied Soft Computing | 2014

Neuro-fuzzy self-tuning of PID control for semiglobal exponential tracking of robot arms

Jorge Armendariz; Vicente Parra-Vega; Rodolfo García-Rodríguez; Sergio Rosales

Graphical abstractDisplay Omitted HighlightsSelf-tuning PID control algorithm based on a single feedback gain using a neuro-fuzzy scheme.Proof stability to demonstrate semiglobal exponential tracking.We claim that our proposal stands for the first one that enforces and proves semiglobal exponential tracking for robot arms using model-free self-tuning PID. The PID controller with constant feedback gains has withstood as the preferred choice for control of linear plants or linearized plants, and under certain conditions for non-linear ones, where the control of robotic arms excels. In this paper a model-free self-tuning PID controller is proposed for tracking tasks. The key idea is to exploit the passivity-based formulation for robotic arms in order to shape the damping injection to enforce dissipativity and to guarantee semiglobal exponential convergence in the sense of Lyapunov. It is shown that a neuro-fuzzy network can be used to tune dissipation rate gain through a self-tuning policy of a single gain. Experimental studies are presented to confirm the viability of the proposed approach.


Neurocomputing | 2016

Neurofuzzy self-tuning of the dissipation rate gain for model-free force-position exponential tracking of robots

Vicente Parra-Vega; Rodolfo García-Rodríguez; Jorge Armendariz

Simultaneous force and position control of robots interacting with a rigid environment has been broadly studied assuming several contact force models, being the differential algebraic - DAE - model the most complete one, however DAE robots show complex and strong nonlinear couplings that make difficult to achieve tracking, when dynamic model is not available. In this paper, considering the fundamental structural properties of DAE robots, in particular passivity and the orthogonalization of force and velocity vectors, it is proposed a model-free neurofuzzy-based self-tuning robot controller for exponential tracking, which is composed of orthogonalized PID-position plus an I-force (If) control terms, and a feed-forward desired force term. The salient feature of this proposal is a novel neurofuzzy self-tuning scheme aimed at tuning the dissipation rate gain (DRG) so as to enforce dissipativity in closed-loop, rather than the standard scheme of tuning the feedback control gains, or the control structure, which in our case stands for a simple constant feedback gain orthogonalized PID + I f controller. In fact, in virtue of such orthogonalization, it emerges a simple and low cost parallel structure of the neuro-fuzzy network that targets solely the DRG so as to drive error dynamics to zero with exponential rate, without any knowledge of robot dynamics or carrying out any approximation of inverse dynamics. Thus, this technique can be applied to other class of systems and controllers that ensure passivity in closed-loop. Simulations show the validity and the feasibility of this new approach.


conference on decision and control | 2012

Dynamic self-tuning PD control for tracking of robot manipulators

Jorge Armendariz; Vicente Parra-Vega; Rodolfo García-Rodríguez; Shinichi Hirai

Motivated by the passivity-based robot control scheme under unknown dynamics, a self-tuning PD controller with bounded time-varying gains is proposed for trajectory tracking of robot manipulators. The tuning procedure is synthesized on-line by means of a neuro-fuzzy recurrent scheme which produces smooth control input for smooth desired trajectories. Semi-global exponential stability of the closed-loop system is guaranteed via Lyapunov theory. Simulation results make evident and viable the potential characteristics of the proposed controller.


intelligent robots and systems | 2013

Rolling a dynamic object with a planar soft-fingertip robot arm

Rodolfo García-Rodríguez; Vicente Parra-Vega

Force-position control through one or multiple robots, or fingers, typically assumes a rigid endpoint without rolling nor slipping. However, there are some interesting tasks where rolling is involved, such as turning a knob (object is pivoting at a fixed rotational axis) or rolling a wheel (object rotational axis is moving). In such a case, rigid endpoint force control becomes very difficult if not impossible, even for us humans. This stems from two facts, firstly, infinitesimally small rigid point does not yield a tangent force, therefore it is very difficult to control it indirectly; and secondly, the pair robot-object stands for a highly non-linear constrained underactuated dynamical systems. In this paper, we aim at exploring rolling of a rigid dynamic circular object with hemispherical deformable fingertip, then with area, not point, contact. The dynamic model and a control scheme are presented inspired in previous works, but regulation of normal and tangential forces, as well as position and orientation of the object are synthesized. In particular, tangential force control proves instrumental to regulate posture, and displacement of the object with a simple transpose Jacobian Cartesian PDF+g control. Regulation of rolling angle and displacement with stable normal and tangential forces are obtained without force sensing, neither any model of the deformation nor any dynamic parameter of the object. To entertain these control objectives, a redundant configuration is required so as to yield local regulation, based on the stability-in-the-manifold criteria, whose dimension is greater than the operational space. Illustrative simulations are discussed that provide insight into the closed-loop numerical performance, and finally, remarks on the structure and potential applications are addressed.


intelligent robots and systems | 2012

Improving physical human-robot interaction through viscoelastic soft fingertips

Jorge Armendariz; Felipe Alberto Machorro-Fernández; Vicente Parra-Vega; Rodolfo García-Rodríguez; Shinichi Hirai

In this paper, we are interested in a scheme that proves effective use of soft fingertips for human-in-the-loop telemanipulation. Motion planning is carried out by the human-in-the-loop to grasp and manipulate an object using viscoelastic soft fingertips. In addition, to grasp an object firmly, an estimated torque is synthesized based on fuzzy inference. Experimental results show that the user confidence presents small variations using soft fingertips. Then, the soft fingertips in pHRI induce a more user dexterity than rigid fingertips.


international conference on control and automation | 2011

Grasping and dynamic manipulation by soft finger-tips without object information

Rodolfo García-Rodríguez; G. Diaz-Rodriguez

By several years, the robotic fingers have been studied using rigid finger-tips to grasp and manipulate an object. Recently, hemispherical soft finger-tips have been used in order to enhance dexterity of the robotic hands where the high friction contact between them, prevents the slipping and improves the grasping stability. In this paper is presented, a new control for grasping and object manipulation under assumption that kinematic parameters of the object and the contact point location between object and finger are unknown. This approach is based on the assumption that the contact must vary depending the rolling contact constraint and taking into account a normal and tangential deformations in the soft finger-tips. A critical role for the establishment of our approach is the distance between center position of the finger-tip and the straight line that crosses the object perpendicularly which should be zero. Simulation results are provided to visualize the stable grasping and some manipulation tasks as the rotation and translation of the object on a pair of soft fingers with three degree of freedom.


Engineering Applications of Artificial Intelligence | 2017

Normal and tangent force neuro-fuzzy control of a soft-tip robot with unknown kinematics

Rodolfo García-Rodríguez; Vicente Parra-Vega

Abstract Assuming that contact kinematics is known, there exists many force robot control schemes, however the common practice of placing a deformable pad at contact makes difficult its implementation. The difficulty stems from the fact that the this pad introduces contact kinematics uncertainties due to the unknown deformation. In this paper, considering the full non-linear constrained rigid robot equipped with a hemispherical soft-tip as end-effector, a force regulator is proposed. To compensate the kinematic uncertainty at contact, induced by the unknown soft-tip deformation, a multi-input single-output (MISO) self-tuning fuzzy-rule emulated neural network (MiFRENN) is used. Additionally, the gravity compensation together with a damping injection term in the controller are used to guarantee local convergence of the normal and tangential force errors at a given equilibrium. The stability domain of the system varying depending on the knowledge-based contribution of the MISO-MiFRENN and the damping injection, which amounts for a novel scheme that can be used for other advanced robotic contact tasks, such as tactile exploration, dexterous manipulation or biped locomotion. Representative simulations illustrate the closed-loop numerical behavior.


ieee-ras international conference on humanoid robots | 2016

A humanoid robot toying a spinning top: Analysis and design

M. Guzman-Alvarado; G. Guzman-Solis; J. Obregon; J. Hernandez-Tuyin; Vicente Parra-Vega; Ernesto Olguín-Díaz; Rodolfo García-Rodríguez

There exists certain unusual and highly demanding human motor tasks that require bimanual high-end dexterous skills, such as throwing a curve ball, skating, RipStik caster boarding, to name a few, wherein precise fast nonlinear dynamics and advanced robust control play a major role. Similarly, the spinning top (ST), an amazingly popular toy across cultures from millennia, has recently motivated formal research due to its apparent complex perplexing physics that maintains it upright without falling even when its rotational axis is inclined, a motion regime we call “dancing”. In this paper, a humanoid robot (HR) that replicates the throwing and dancing motion regimes of a 6D ST toy (STT) is proposed, using full nonlinear models. A finite-time continuous robust, yet model-and chattering-free controller is synthesized for the HR to track the aggressive but smooth trajectories from a real-time motion capture system of an expert human player. Simulations show the successful throwing and dancing of STT. Moreover, analysis suggests a trade-off on theoretical and practical aspects subject to current HR technological limitations.


intelligent robots and systems | 2015

Dexterous dynamic optimal grasping of a circular object with pose regulation using redundant robotic soft-fingertips

Rodolfo García-Rodríguez; Marco Villalva-Lucio; Vicente Parra-Vega

Dexterous object manipulation with robotic hands (subject to holonomic constraints) usually requires the capacity of fingertips to roll onto the object, which is very difficult to achieve with frictionless point contact model . As an alternative, deformable contact model has been considered based on hemispherical shape end-effector to yield rolling. However, it entails dexterity at the expense of dealing with normal and tangential forces, as well as more elaborated dynamic models. In this paper, a passivity-based controller is proposed for redundant robotic fingers with hemi-spherical deformable fingertips to manipulate dexterously a circular dynamic object. Redundancy and rolling are exploited to control normal and tangent contact forces to yield an optimal grasping. The optimal grasping is based on to align dynamically the normal forces applied to the object that allow its manipulation with minimum tangent forces. Stability conditions are presented to guarantee local asymptotic convergence. Finally, numerical simulations show the performance of the forces toward desired pose. This approach can be extended to objects with arbitrary shape that admit a local decomposition by a circular curvature.


IFAC-PapersOnLine | 2015

Dexterous Dynamic Optimal Grasping of a Circular Object subject to Gravity with Soft-fingertips

Rodolfo García-Rodríguez; Marco Villalva-Lucio; Vicente Parra-Vega

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