This paper presents a path planning method for actuated tensegrity structures with quasi-static motion. The valid configurations for such structures lay on an equilibrium manifold, which is implicitly defined by a set of kinematic and static constraints. The exploration of this manifold is difficult with standard methods due to the lack of a global parameterization. Thus, this paper proposes the use of techniques with roots in differential geometry to define an atlas, i.e., a set of coordinated local parameterizations of the equilibrium manifold. This atlas is exploited to define a rapidly-exploring random tree, which efficiently finds valid paths between configurations. However, these paths are typically long and jerky and, therefore, this paper also introduces a procedure to reduce their control effort. A variety of test cases are presented to empirically evaluate the proposed method. (C) 2015 Elsevier Ltd. All rights reserved.
This technical report introduces the concepts, problems and a possible solution for ROS multi-master systems, that is, systems build from two or more ROS networks, each with its own roscore node. In general this environment would correspond to multi-robot systems, either mobile platforms or manipulators.
The ROS framework already provides a solution for such systems, multimaster_fkie, which is presented and briefly described in thisThe ROS framework already provides a solution for such systems, multimaster_fkie, which is presented and briefly described in this technical report, together with the network setup necessary to make it work properly.
Two different configurations are discussed in this technical report, simple ROS networks with a single computer each, and more complex ROS networks with two or more computers each. In both cases, real examples are provided using robots available at IRI.
This technical report describes the design (both hardware and software) of an embedded controller for the Staüli work-cell available at the perception and manipulation laboratory at IRI. This system is based on a commercial embeeded computer (Beaglebone Black) and it is capable of managing all the work-cell devices. This include a custom planar XY robot, two simple grippers at the end effector of each Staübli robot, a six degrees of freedom force and torque sensor and optionally the two Staülbi robots themselves.
This embedded system also monitors all the safety features integrated into the work-cell to provide updated information about the current state of the work-cell to all the device drivers and control programs. The safety featues available at the Staübli work cell include several emergency stop buttons, a laser curtain surrounding the perimeter of the work-cell and two mechanical fuses at the last joint of the Staübli robot.
This document is intended as a complete reference manual of the embedded system, both from a software and a hardware points of view, for maintinance purposes and also to alow the addition of new features and upgrades in the future.
This technical report provides all the information necessary to operate all the elements that integrate the Staübli work-cell at the perception and manipulation laboratory at IRI. A detailed description of each of the robots, safety features, sensors and actuators available at the work-cell is presented. Special attention is paid to the integration of the safety features integrated into the operation of the robots of the work-cell. Also, for maintenance purposes and future upgrades, a detailed description of the electrical wiring of the control box, as well as its input an output connectors, is presented.
This technical report describes the work done to develop a new navigation scheme for an autonomous car-like robot available at the Mobile Robotics Laboratory at IRI. To plan the general path the robot should follow (i.e. the global planner), a search based planner algorithm, with motion primitives which take into account the kinematic constraints of the robot, is used. To actually execute the path and avoid dynamic obstacles (i.e the local planner) a modification of the DWA algorithm is used, which takes into account the kinematic constraints of the ackermann configuration to generate and evaluate possible trajectories for the robot. The whole navigation scheme has been integrated into the ROS middleware navigation framework and tested on the real robot and also in a simulator.
The HumanoidLab is a more than 5 year old activity aimed to use educational robots to approach students to our Research Centre. Different commercial educative humanoid platforms have been used to introduce students to different aspects of robotics using projects and offering guidance and assistance. About 40 students have performed small mechanics, electronics or programming projects that are used to improve the robots by adding features. Robotics competitions are used as a motivation tool. A two weeks course was started that has received 80 undergraduate students, and more than 100 secondary school students in a short version. The experience has been very positive for students and for the institution: some of these students have performed their scholar projects and research in robotics and continue enrolled in the robotics field, and some of them are currently in research groups at IRI.
This document outlines the most important concepts presented during a workshop about the iCub robot done at the Instituto Italiano di Technologia in Genova. Mechanical, electronic as well as rmware and software issues are presented, and the basic procedures to detect and solve the most common problems are described. The most important goal of this workshop was to get the necessary skills to perform the most
basic maintenance of the robot without having to depend on the support from IIT. Also a brief introduction to the main issues of the control of the robot were provided.
The main objective of this paper is twofold. First, to conclude the overview about
tensegrity frameworks, started by the same authors in a previous work, covering the most important dynamic aspects of such structures. Here, the most common approaches to tensegrity dynamic modeling used so far are presented, giving the most important results about their dynamic behavior under external action. Also, the main underlying problems are identified which allow the authors to give a clear picture of the main research lines currently open, as well as the most relevant contributions in each of them, which is in fact the second main objective of this paper. From the extensive literature available on the subject, four main areas have been identified: design and form-finding methods which deal with the problem of finding stable configurations, shape changing algorithms which deal with the
problem of finding stable trajectories between them and, also control algorithms
which take into account the dynamic model of the tensegrity structure and possible
external perturbations to achieve the desired goal and performance.
Finally, some applications of such structures are presented emphasizing the increasing interest of the scientific community on tensegrity structures.
The interest of the robotics community on humanoid
robots is growing, specially in perception,
scene understanding and manipulation in humancentered
environments, as well as in human-robot
interaction. Moreover, humanoid robotics is one
of the main research areas promoted by the European
research program. Here we present some
projects and educational initiatives in this direction
carried out at the Institut de Robòtica i Informàtica Industrial, CSIC-UPC.
This paper hands in a review of the basic issues about the statics of tensegrity structures. Definitions and notation for the most important concepts, borrowed from the vast existing literature, are summarized. All of these concepts and definitions provide a complete mathematical framework to analyze the rigidity and stability properties of tensegrity structures from three different, but related, points of view: motions, forces and energy approaches. Several rigidity and stability definitions are presented in this paper and hierarchically ordered, from the strongest condition of infinitesimal rigidity to the more wide concept of simple rigidity, so extending some previous classifications already available. Important theorems regarding the relationship between these definitions are also put together to complete the static overview of tensegrity structures. Examples of different tensegrity structures belonging to each of the rigidity and stability ca\-tegories presented are described and analyzed. Concluding the static analysis of tensegrity structures, a review of existing form-finding methods is presented.