Visual Servoing and Robust Object Manipulation Using Symmetries and Conformal Geometric Algebra

Object tracking and manipulation is an important process for many applications in robotics and computer vision. A novel 3D pose estimation of objects using reflectionally symmetry formulated in Conformal Geometric Algebra (CGA) is proposed in this work. The synthesis of the kinematics model for robots and a sliding mode controller using the CGA approach is described. Real time implementation results are presented for the pose estimation of object using a stereo vision system.ITESO, A.C.CINVESTA

Robust Tracking of Bio-Inspired References for a Biped Robot Using Geometric Algebra and Sliding Modes

Controlling walking biped robots is a challenging problem due to its complex and uncertain dynamics. In order to tackle this, we propose a sliding mode controller based on a dynamic model which was obtained using the conformal geometric algebra approach (CGA). The CGA framework permits us to use lines, points, and other geometric entities, to obtain the Lagrange equations of the system. The references for the joints of the robot were bio-inspired in the kinematics of a walking human body. The first and second derivatives of the reference signal were obtained through an exact robust differentiator based on high order sliding modes. The performance of the proposed control scheme is illustrated through simulation.CINVESTA

Robust Tracking of Bio-Inspired References for a Biped Robot Using Geometric Algebra and Sliding Mode Control

Controlling walking biped robots is a challenging problem due to its complex and uncertain dynamics. In order to tackle this, we propose a sliding mode controller based on a dynamic model which was obtained using the conformal geometric algebra approach (CGA). The CGA framework permits us to use lines, points, and other geometric entities, to obtain the Lagrange equations of the system. The references for the joints of the robot were bio-inspired in the kinematics of a walking human body. The first and second derivatives of the reference signal were obtained through an exact robust differentiator based on high order sliding mode. The performance of the proposed control schemes are illustrated through simulation.ITESO, A.C

Motor Eyes: Mechanical Platform for a Binocular Robotic Vision System

Stereoscopic vision systems require high computational power to perform image processing for 3D reconstruction of a scene. Synchronizing eye movements through mechanical coupling can reduce this processing power. To investigate this potential, the project team developed a mechanical platform for a binocular robotic vision system that uses stepper motors and slider linkages to achieve coupled pan, coupled tilt and coupled vergence eye movements. A prototype, controlled by an Arduino Uno, was constructed. The prototype achieved eye rotation speeds comparable to human saccadic eye motion and was capable of focusing on specified points with some position error caused by the prototype’s high sensitivity to misalignments of mechanical parts

Motor Eyes: Mechanical Platform for a Binocular Robotic Vision System

Stereoscopic vision systems require high computational power to perform image processing for 3D reconstruction of a scene. Synchronizing eye movements through mechanical coupling can reduce this processing power. To investigate this potential, the project team developed a mechanical platform for a binocular robotic vision system that uses stepper motors and slider linkages to achieve coupled pan, coupled tilt and coupled vergence eye movements. A prototype, controlled by an Arduino Uno, was constructed. The prototype achieved eye rotation speeds comparable to human saccadic eye motion and was capable of focusing on specified points with some position error caused by the prototype’s high sensitivity to misalignments of mechanical parts

Motor Eyes: Mechanical Platform for a Binocular Robotic Vision System

Stereoscopic vision systems require high computational power to perform image processing for 3D reconstruction of a scene. Synchronizing eye movements through mechanical coupling can reduce this processing power. To investigate this potential, the project team developed a mechanical platform for a binocular robotic vision system that uses stepper motors and slider linkages to achieve coupled pan, coupled tilt and coupled vergence eye movements. A prototype, controlled by an Arduino Uno, was constructed. The prototype achieved eye rotation speeds comparable to human saccadic eye motion and was capable of focusing on specified points with some position error caused by the prototype’s high sensitivity to misalignments of mechanical parts

Robot Manipulators

Robot manipulators are developing more in the direction of industrial robots than of human workers. Recently, the applications of robot manipulators are spreading their focus, for example Da Vinci as a medical robot, ASIMO as a humanoid robot and so on. There are many research topics within the field of robot manipulators, e.g. motion planning, cooperation with a human, and fusion with external sensors like vision, haptic and force, etc. Moreover, these include both technical problems in the industry and theoretical problems in the academic fields. This book is a collection of papers presenting the latest research issues from around the world

Combining central pattern generators with the electromagnetism-like algorithm for head motion stabilization during quadruped robot locomotion

Visually-guided locomotion is important for autonomous robotics. However, there are several difficulties, for instance, the head shaking that results from the robot locomotion itself that constraints stable image acquisition and the possibility to rely on that information to act accordingly. In this article, we propose a controller architecture that is able to generate locomotion for a quadruped robot and to generate head motion able to minimize the head motion induced by locomotion itself. The movement controllers are biologically inspired in the concept of Central Pattern Generators (CPGs). CPGs are modelled based on nonlinear dynamical systems, coupled Hopf oscillators. This approach allows to explicitly specify parameters such as amplitude, offset and frequency of movement and to smoothly modulate the generated oscillations according to changes in these parameters. We take advantage of this particularity and propose a combined approach to generate head movement stabilization on a quadruped robot, using CPGs and a global optimization algorithm. The best set of parameters that generates the head movement are computed by the electromagnetism-like algorithm in order to reduce the head shaking caused by locomotion. Experimental results on a simulated AIBO robot demonstrate that the proposed approach generates head movement that does not eliminate but reduces the one induced by locomotion

Evolution strategies combined with central pattern generators for head motion minimization during quadruped robot locomotion

In autonomous robotics, the head shaking induced by locomotion is a relevant and still not solved problem. This problem constraints stable image acquisition and the possibility to rely on that information to act accordingly. In this article, we propose a movement controller to generate locomotion and head movement. Our aim is to generate the head movement required to minimize the head motion induced by locomotion itself. The movement controllers are biologically inspired in the concept of Central Pattern Generators (CPGs). CPGs are modelled based on nonlinear dynamical systems, coupled Hopf oscillators. This approach allows to explicitly specify parameters such as amplitude, offset and frequency of movement and to smoothly modulate the generated oscillations according to changes in these parameters. Based on these ideas, we propose a combined approach to generate head movement stabilization on a quadruped robot, using CPGs and an evolution strategy. The best set of parameters that generates the head movement are computed by an evolution strategy. Experiments were performed on a simulated AIBO robot. The obtained results demonstrate the feasibility of the approach, by reducing the overall head movement