Nirvana Popescu

Frequency criteria for the grasping control of a hyper-redundant robot

The paper focuses on hyper-redundant arms with continuum elements that perform the grasping function by coiling. First, there is concern with the dynamic model of the continuum arm for the position control during non-contact operations with the environment. A frequency stability criterion based on the Kahman - Yakubovich - Popov Lemma and P and PD control algorithms is proposed. Then, the grasping control of the arm in contact with a load is analyzed. The dynamics of the system are discussed and an extension of the Popov criterion is endorsed. The control algorithms based on SMA actuators are introduced. Numerical simulations and experimental results of the arm motion toward an imposed target are presented.

Position and force control of the grasping function for a hyperredundant arm

The grasping control problem for a hyperredundant manipulator is presented. The dynamic model is derived by using Lagrange equations developed for infinite dimensional systems. The algorithms for the position and force control are proposed. The arm fluid pressure control is inferred and the conditions that ensure the stability of the motion are discussed. Numerical simulations are presented.

Force observer-based control for a rehabilitation hand exoskeleton system

This paper is a component of a research project regarding the design and development of an Intelligent Haptic Robot-Glove for the rehabilitation of the patients that have a diagnosis of a cerebrovascular accident. In this paper, the control system for a rehabilitation hand exoskeleton is discussed. In order to avoid the complex problems given by a distributed sensor network, this paper treats the problem of the compliance force control by using observers: a velocity observer, a force observer and a disturbance observer. Two control solutions are discussed. First, the disturbance effects are eliminated by a cascade closed loop control with velocity and force observers. Then, a disturbance observer is used to compensate the compliance effects. The performance of the control systems is demonstrated by the simulation.

A decoupled sliding mode control for a continuum arm

The paper treats the control problem of a class of robots constituted by a chain of continuum segments. The technological model basis is a central, long and thin, highly flexible and elastic backbone. The segment control system is a decoupled one. The main parameters of the arm control are determined by the curvature and curvature gradient. The dynamic model is inferred. The primary benefit of the proposed method is that the dynamic equations are represented by a set of ODE’s in time instead of PDE’s in time and space, and the new curvature gradient lumped parameter model is used. A sliding mode control system is used in order to achieve the desired shape of the arm. The stability of the closed-loop control system is proven. Numerical simulations and an experimental platform are also provided to verify the effectiveness of the presented approach.

Intelligent Haptic Robotic Glove for patients diagnosed with cerebrovascular accidents

This paper is based on a research project regarding the design and development of an Intelligent Haptic Robot-Glove (IHRG) for the rehabilitation of the patients that have a diagnosis of a cerebrovascular accident. The IHRG is an exoskeleton that supports the human hand and hand activities by using a control architecture for dexterous grasping and manipulation. This IHRG is a medical device that acts in parallel to a hand in order to compensate some lost function. A novel approach for the development of an exoskeleton assistive hand is considered, a “mechatronic approach” for the integration of the mechanical structure, the sensory, the actuation system and the virtual and control system.

Coil function control problem for a hyperredundant robot

The paper focuses on the control problem of a hyperredundant robot that performs the coil function of grasping. First, the dynamic model of a hyperredundant arm with continuum elements produced by flexible composite materials in conjunction with active-controllable electro-rheological fluids is analyzed. Secondly, both problems, i.e. the position control and the force control are approached. The difficulties determined by the complexity of the non-linear integral-differential equations are avoided by using a basic energy relationship of this system. Energy-based control laws are introduced for the position control problem. A force control method is proposed, namely the DSMC method in which the evolution of the system on the switching line by the ER fluid viscosity is controlled. Numerical simulations are also presented.

Exoskeleton Design of an Intelligent Haptic Robotic Glove

This paper is based on the results of a research project regarding the design and development of an Intelligent Haptic Robot-Glove (IHRG) for the rehabilitation of the patients that have a diagnosis of a cerebrovascular accident. The IHRG is an exoskeleton that supports the human hand and hand activities by using a control architecture for dexterous grasping and manipulation. The five-fingered assistive robotic glove is designed with mechanical compliance of human finger. The biomechanical elements of the exoskeleton assistive hand are designed considering: motion in different planes, adapted to patients hand, possible to train pinch and grasp, opening/closing game. The actuation system is also studied and designed. The paper provides an overview of hand rehabilitation and evaluation techniques.

Hardware design and implementation of an Intelligent Haptic Robotic Glove

This paper is based on the results of a research project regarding the design and development of an Intelligent Haptic Robot-Glove (IHRG) for the rehabilitation of the patients that have a diagnosis of a cerebrovascular accident. The IHRG was designed and implemented in our laboratory considering the fact that for any patient it will be more comfortable to make medical exercises in his own home. The proposed IHRG has a great advantage - the possibility to specify some vocal commands, which will help the patient to make a lot of medical exercises.

Robot telemanipulation system

The article presents a solution for the teleoperation of a robot hand and arm designed as a complex system that captures human motion and controls the robot into mimicking the human actions. This hybrid system allows the robot execution to be guided by human actions, therefore decreasing the planning complexity and allowing the robot to perform more complex movements and to use the human capacity of adapting to unexpected situations.

A Distributed Force and Position Control for Tentacle Manipulator

Abstract The grasping control problem for a hyperredundant arm is studied. Frist, dynamic model of the arm is analyzed. The control problems are divided in the subproblems: the position control in a desired reaching area, the control of the arm around the object-load and the force control of grasping. The difficulties determined by the complexity of the non-linear integral-differential equations are avoided by using a very basic energy relationship of this system. First, the dynamic control of the arm for a desired reaching area is inferred. Then, the position controland the force control for grasping are discussed. Numerical simulation are presented.