Elvia R. Palacios-Hernandez

Leader-Follower Formation for Nonholonomic Mobile Robots: Discrete-Time Approach

This paper presents a novel solution for the classical leader-follower formation problem considering the case of nonholonomic mobile robots. A formation control strategy is proposed in a discrete-time context by considering the exact discrete-time discretization of the non-linear continuous-time kinematic model of the vehicle. The geometric formation of the robots allows us to derive an alternative model that describes the time evolution of the relative distance and angle between the robots. These variables are obtained in real-time by a vision-based localization system on board, in which the follower robot is equipped with a Kinect device, together with a recognition board mounted on the leader robot. The boundedness of the relative position error is formally proven by considering a feedback law that is delayed by one sampling period of time. Numerical simulations and real-time experiments are presented to verify the performance of the control strategy.

A proposed software architecture for controlling a service robot

In this article, we propose a software architecture for controlling a mobile robot that works as a guide on human environments. The architecture is divided into three broad action modules lead by a supervisor. The decision is based on current user behavior in order to provide better service to people.

Characterization of two force sensors to be used in a robotic hand

In this paper, are presented the characterization of two force sensors, in bias to incorporate them to the fingers of a robotic hand. The main goal of this work is to determine as main characteristic, the response of each sensor, in order to decide, which of them is the most effective for manipulation tasks in a mobile robotic platform. Manipulation mobile robot tasks, require to adapt its behavior and fingers configuration depending of the type and form of diverse objects. The first evaluated sensor is a cheap resistive force sensor and second is a piezoelectric force sensor. As robotic hand and then sensors will be incorporate on a mobile platform, sensor signals are sent to the a computer through a data card acquisition; an Arduino card has been used. We show the evaluation, results and conclusions of the experiments done.

A switching position/force controller for two independent finger gripper over ROS

Mobile Robot Manipulation of diverse objects is still a very difficult task. Progress in mobile robot localization, path planning and perception, have allowed to mobile robots to contend with manipulation in some domains. Parallels manipulators are commonly used, however in order to do robust grasping, as humans do, the use of independent fingers are increasing. The problem of independent fingers is to assure robust manipulation on behalf the variations between the position and control of the fingers. In this work it is presented a system for object manipulation by a robotic gripper with independent fingers (with angular motion) each of them equipped with a position/force sensor. The system deal with the problem of adjusting the position of the fingers controlled independently over the middleware ROS, in order to guaranty that object is at center position on the gripper. Once it is done, the system switch to a force controller apply the correct force on each independent finger. The proposed system uses two proportional integral derivative (PID) controller; one to control the position of the object, and the second one to control the force applied on the object. The experiments are carried out to asses, if the object is centered and lifted by the gripper without releasing. Results obtained are presented and discussed.