Collision-free path planning for robots using B-splines and simulated annealing

This thesis describes a technique to obtain an optimal collision-free path for an automated guided vehicle (AGV) and/or robot in two and three dimensions by synthesizing a B-spline curve under geometric and intrinsic constraints. The problem is formulated as a combinatorial optimization problem and solved by using simulated annealing. A two-link planar manipulator is included to show that the B-spline curve can also be synthesized by adding kinematic characteristics of the robot. A cost function, which includes obstacle proximity, excessive arc length, uneven parametric distribution and, possibly, link proximity costs, is developed for the simulated annealing algorithm. Three possible cases for the orientation of the moving object are explored: (a) fixed orientation, (b) orientation as another independent variable, and (c) orientation given by the slope of the curve. To demonstrate the robustness of the technique, several examples are presented. Objects are modeled as ellipsoid type shapes. The procedure to obtain the describing parameters of the ellipsoid is also presented

Intelligent gripper design and application for automated part recognition and gripping

Intelligent gripping may be achieved through gripper design, automated part recognition, intelligent algorithm for control of the gripper, and on-line decision-making based on sensory data. A generic framework which integrates sensory data, part recognition, decision-making and gripper control to achieve intelligent gripping based on ABB industrial robot is constructed. The three-fingered gripper actuated by a linear servo actuator designed and developed in this project for precise speed and position control is capable of handling a large variety of objects. Generic algorithms for intelligent part recognition are developed. Edge vector representation is discussed. Object geometric features are extracted. Fuzzy logic is successfully utilized to enhance the intelligence of the system. The generic fuzzy logic algorithm, which may also find application in other fields, is presented. Model-based gripping planning algorithm which is capable of extracting object grasp features from its geometric features and reasoning out grasp model for objects with different geometry is proposed. Manipulator trajectory planning solves the problem of generating robot programs automatically. Object-oriented programming technique based on Visual C++ MFC is used to constitute the system software so as to ensure the compatibility, expandability and modular programming design. Hierarchical architecture for intelligent gripping is discussed, which partitions the robot’s functionalities into high-level (modeling, recognizing, planning and perception) layers, and low-level (sensing, interfacing and execute) layers. Individual system modules are integrated seamlessly to constitute the intelligent gripping system

Un model d'incertesa fitada per a la propagació i fusió d'informació geomètrica incerta

En esta tesis se desarrolla un sistema de tratamiento de informaciones geométricas con incertidumbre, basado en la propagación y fusión de regiones elipsoidales. Se adopta un modelo de incertidumbre acotada en el espacio de parámetros por conjuntos elipsoidales. Estos conjuntos pueden ser degenerados o no, permitiendo representar tanto informaciones parciales como completas de los elementos observados.Se ha obtenido una formula para calcular la fusión de dos elipsoides. Es decir, que dadas varias observaciones de un mismo elemento, cada una con su región elipsoidal de incertidumbre, la operación de fusión calcula la menor cota elipsoidal.La propagación de elipsoides se hace a través de las ecuaciones correspondientes a las relaciones geométricas entre los elementos del entorno. Se ha obtenido una formula que generaliza la propagación de elipsoides a los casos degenerados usando matrices pseudoinversas y permitiendo así también la propagación de informaciones parciales.Se presenta un algoritmo para la actualización global de las informaciones que se basa en la fusión y la propagación. Se implementa sobre un grafo cuyos nodos representan los elementos del entorno y cuyos arcos representan las relaciones entre ellos.Finalmente se expone, como ejemplo de aplicación del sistema desarrollado, un algoritmo para la imposición de condiciones de consistencia en dibujos poligonales con posición inserta de los vértices, para ser proyecciones bidimensionales de poliedros. Las condiciones de consistencia se definen de forma natural en el grafo y la imposición se hace con el algoritmo de propagación global