Fernando Torres Medina

Web teleoperation of robots with simulation feedback

The use of a robot arm for industry is a very common problem. A great quantity of these robots have to have a remote human controller to achieve its task successfully. The user knows what is happening with the robot arm through sensors. This information has to arrive to the user and if it consists of a video then the system needs a high bandwidth to carry it to the user in real-time. The present system uses a simulation feedback instead of video information; this type of feedback gets as much information as a video with a lower bandwidth. The simulation of the system is based on virtual reality modeling feedback language (VRML) to model the robot arm which reproduces the movements of the real robot. This method of feedback has the advantage of required little information to afford the user a real approach to the system. The proposed system lets the user move the robot arm with different point-to-point trajectories and different possibilities of movement. The aim of this kind of laboratory is to facilitate the access for students and professionals in the field of robotics. This system is used for teaching university students the themes of robotics. It improves the training of the students permitting them access to a real robot which would be impossible for universities to afford if each student needed his own robot to practice. This paper presents a remote laboratory approach for experimentation with a real robot, which uses the communication techniques of the web.

Disassembly movements for geometrical objects through heuristic methods

This paper presents a non-destructive disassembly method. It tries to make up for limitations of other methods based on contact surfaces. It uses a contact surfaces graph and shows an algorithm to obtain the movement sequence needed for the disassembly of two objects, using a composition of transfer movement. It performs a second filter to obtain the exact disassembly direction from the group of directions obtained from the contact surfaces. The filter employs a mobile robotic heuristic to feedback the contact surface graph throughout the disassembly process. The heuristic generates an environment map to infer the region where the probability of collision with the other objects is lower. To achieve the disassembly the paper presents a method for modeling the elements implied in the disassembly process. This virtual model of the environment allows us to quickly process the elements and the simulation of the movements for disassembly. This model can be used to either schedule the disassembly process or to test, during the design stage, whether the products can be easily disassembled.This paper presents a non-destructive disassembly method. It tries to make up for limitations of other methods based on contact surfaces. It uses a contact surfaces graph and shows an algorithm to obtain the movement sequence needed for the disassembly of two objects, using a composition of transfer movement. It performs a second filter to obtain the exact disassembly direction from the group of directions obtained from the contact surfaces. The filter employs a mobile robotic heuristic to feedback the contact surface graph throughout the disassembly process. The heuristic generates an environment map to infer the region where the probability of collision with the other objects is lower. To achieve the disassembly the paper presents a method for modeling the elements implied in the disassembly process. This virtual model of the environment allows us to quickly process the elements and the simulation of the movements for disassembly. This model can be used to either schedule the disassembly process or to test, during the design stage, whether the products can be easily disassembled.

Product disassembly scheduling using graph models

Disassembly problem is a current issue for industrial companies. Governments of different countries promote research in this field. This paper presents the following points. First a brief state of the art in disassembly planning. Next it exposes a solution for the disassembly problem of industrial products. It uses a combination between direct and indirect graph representation for the product, all components that have physical entity are considered as vertices of the graph. Edges of the graph represent the relationships between vertices. There are three different types of edges. First corresponds with accessibility and fastener restrictions. Second corresponds with direct relations between components without fasteners. Last one corresponds with contact relationships, which represent an indifferent choice of the vertices. Based on that representation the paper exposed a method to find the best sequence to disassemble a component. Costs of disassembling each component and of changing tool between each pair of vertices and different sequences of the disassembly are taken into consideration. This method consists in a function minimization defined in the graph domain. In the last point of the paper this method is tested with a remote control disassembly. This method gives a solution to the problem, if several solutions, with the same cost, exist then it gives all of them, and any one of these disassemble sequences could be used to achieve to the target component.Disassembly problem is a current issue for industrial companies. Governments of different countries promote research in this field. This paper presents the following points. First a brief state of the art in disassembly planning. Next it exposes a solution for the disassembly problem of industrial products. It uses a combination between direct and indirect graph representation for the product, all components that have physical entity are considered as vertices of the graph. Edges of the graph represent the relationships between vertices. There are three different types of edges. First corresponds with accessibility and fastener restrictions. Second corresponds with direct relations between components without fasteners. Last one corresponds with contact relationships, which represent an indifferent choice of the vertices. Based on that representation the paper exposed a method to find the best sequence to disassemble a component. Costs of disassembling each component and of changing tool between each pair of vertices and different sequences of the disassembly are taken into consideration. This method consists in a function minimization defined in the graph domain. In the last point of the paper this method is tested with a remote control disassembly. This method gives a solution to the problem, if several solutions, with the same cost, exist then it gives all of them, and any one of these disassemble sequences could be used to achieve to the target component.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Finger readjustment algorithm for object manipulation based on tactile information

This paper presents a novel algorithm which registers pressure information from tactile sensors installed over the fingers of a robotic hand in order to perform manipulation tasks with objects. This algorithm receives as an input the joint trajectories of the fingers which have to be executed and adapts it to the real contact pressure of each finger in order to guarantee that undesired slippage or contact-breaking is avoided during the execution of the manipulation task. This algorithm has been applied not only for the manipulation of normal rigid bodies but also for bodies whose centre of mass can be changed during the execution of the manipulation task.

Simulation and Scheduling of Real-Time Computer Vision Algorithms

A fully integrated development tool for computer vision systems has been built in the framework of this paper. There are many applications that help the user in the design of such systems, using graphical interfaces and function libraries. Even in some cases, the final source code can be generated by these applications. This paper goes a step beyond; it allows the development of computer vision systems from a distributed environment. Besides, and as a distinctive characteristic with regard to other similar utilities, the system is able to automatically optimize task scheduling and assignment, depending on the available hardware.

Multi-fingered robotic hand planner for object reconfiguration through a rolling contact evolution model

This paper presents a novel planner for dexterous manipulation with a multi-fingered robotic hand. This planner receives as input an initial grasp of the object and a desired trajectory of the object in task space (position and orientation). The planner computes the movements of the fingers which are required to move the object along this trajectory without breaking contacts. It uses a triangle mesh representation of the surfaces of the fingers and the object and a new contact evolution graph in order to compute all the possible transitions between the contact primitives of their surfaces. This planner have been implemented as a program which communicates with a five-fingered hand in order to test them in real manipulation tasks.

SASEPA: Simultaneous Allocation and Scheduling with Exclusion and Precedence Relations Algorithm

An algorithm for allocating and scheduling tasks in multiprocessor environments is presented. Its main characteristic is its orientation towards machine vision applications. In this sense it deals with the peculiarities of systems which combine generic-type processors with Image Acquisition and Processing Boards. The main goal of the algorithm is total processing time reduction; such are the requirements when we deal with automated industrial inspection applications. By simultaneously tackling the phases of allocation and scheduling, the results obtained are better than those offered by traditional algorithms. The system is applied to a process of citrus fruit inspection, and its performances are also evaluated over randomly generated task graphs.

2-D VISUAL SERVOING WITH INTEGRATION OF MULTIPLE PREDICTIONS OF MOVEMENT BASED ON KALMAN FILTER

Abstract In this paper, a visual servoing for the tracking of objects in a plane using a fixed camera system is shown. The method proposed of tracking makes use of a variable number of trackers determined automatically. The integration of the predictions of each of them affords a flexible and robust system of tracking. The studies of efficiency carried out reflect that the delays produced are suitable for use in visual servoing. The proposed system can be generalized to tracking three-dimensional objects with movable cameras.