Inverse kinematics of a humanoid robot with non-spherical hip: a hybrid algorithm approach

This paper describes an approach to solve the inverse kinematics problem of humanoid robots whose construction shows a small but non negligible offset at the hip which prevents any purely analytical solution to be developed. Knowing that a purely numerical solution is not feasible due to variable efficiency problems, the proposed one first neglects the offset presence in order to obtain an approximate “solution” by means of an analytical algorithm based on screw theory, and then uses it as the initial condition of a numerical refining procedure based on the Levenberg‐Marquardt algorithm. In this way, few iterations are needed for any specified attitude, making it possible to implement the algorithm for real‐time applications. As a way to show the algorithm’s implementation, one case of study is considered throughout the paper, represented by the SILO2 humanoid robot

A novel "resilience viewpoint" to aid in engineering resilience in systems of systems (SoS)

Designing evolutionary systems to meet stakeholder expectations on safety, reliability and overall resilience is of great importance in an age of interconnectivity and high dependency systems. With incidents and disruptions becoming more frequent in recent years, the requirement for systems to demonstrate high levels of resilience given the economic, political and temporal dimensions of complexity, resilience is of great significance today. Systemic resilience is of high importance at the global level. Therefore, the role of the system engineer and architect is becoming more demanding due to the need to consider requirements from a broader range of stakeholders and to implement them into early conceptual designs. The early modeling process of all systems is common ground for most engineering projects, creating an architecture to both understand a system and to design future iterations by applying model-based processes has become the norm. With the concept of systems-ofsystems (SoS) becoming common language across multiple engineering domains, model-based systems engineering techniques are evolving hand-in-hand to provide a paradigm to better analyse current and future SoS. The intrinsic characteristics of the constituent systems that make up the SoS make the challenge of designing and maintaining the reliability and resilience of a systems extremely difficult. This paper proposes a novel viewpoint, within an architecture framework (based around DoDAF, MoDAF and UPDM) to aid systems architects explore and design resilient SoS. This is known as the Resilience Viewpoint. Much of the research in the area is focussed on critical infrastructure (CI), looking at telecommunication networks, electric grid, supply networks etc, and little has been done on a generalizable tool for SoS architecture analysis, especially using existing modeling languages. Here, the application of the ‘Resilience Viewpoint’ is demonstrated using a case study from an integrated water supply system of systems, to portray its potential analytical capabilities

Coordinated Control Of Mobile Robots Based On Artificial Vision

This work presents a control strategy for coordination of multiple robots based on artificial vision to measure the relative posture between them, in order to reach and maintain a specified formation. Given a leader robot that moves about an unknown trajectory with unknown velocity, a controller is designed to maintain the robots following the leader at a certain distance behind, by using visual information about the position of the leader robot. The control system is proved to be asymptotically stable at the equilibrium point, which corresponds to the accomplishment of the navigation objective. Experimental results with two robots, a leader and a follower, are included to show the performance of the vision-based control system

An Extension to Philips' Algorithm for Moment Calculation

Abstract. A new reformulation of Philips’ algorithm for the computation of discrete image moments is presented. As Philips’ method, the new reformulation produces the same exact results but in a faster manner. Moment contributions due to the presence of holes in the shape (which are not taken into account, to our knowledge, into any boundary based method for moment calculation including Philips’) are also introduced into the new method

Generación automática de mapas 3D interactivos para robots móviles y su uso en la planificación de movimientos

This paper presents the development of a system for obtaining maps of the unknown environment of a mobile robot based on the range information provided by a laser sensor, as well as the automatic representation of this information in the form of a virtual world (MV) interactive three-dimensional Internet. The developed system allows, in addition, the representation of the free space found in the environment as a graph in which the most suitable routes can be determined automatically to go from one place to another of the previously mapped environment. The system developed not only facilitates the programming of the trajectories but also allows a safe operation of the robot by preventing collisions through its reactive navigation system.En este trabajo se presenta el desarrollo de un sistema de obtención de mapas del entorno desconocido de un robot móvil basado en la información de rango provista por un sensor láser, así como la representación automática de esta información en forma de un mundo virtual (MV) tridimensional interactivo accesible por Internet. El sistema desarrollado permite, además, la representación del espacio libre encontrado en el entorno como un grafo en el cual pueden determinarse automáticamente las rutas más adecuadas para ir de un lugar a otro del entorno previamente cartografiado. El sistema desarrollado no sólo facilita la programación de las trayectorias sino que permite una operación segura del robot al impedir colisiones mediante su sistema de navegación reactiva

Haptic Manipulation of Deformable Objects in Hybrid Bilateral Teleoperation System

The aim of this work is the integration of a virtual environment containing a deformable object, manipulated by an open kinematical chain virtual slave robot, to a bilateral teleoperation scheme based on a real haptic device. The virtual environment of this hybrid bilateral teleoperation system combines collision detection algorithms, dynamical, kinematical and geometrical models with a position–position and/or force–position bilateral control algorithm, to produce on the operator side the reflected forces corresponding to the virtual mechanical interactions, through a haptic device. Contact teleoperation task over the virtual environment with a flexible object is implemented and analysed

3D Mapping for Mobile Robots Using Interactive Virtual Worlds and Internet Teleoperation

In this paper we intend to recreate an interactive 3D virtual version of the real environment of a mobile robot and to ensure a bi-directional interaction with all the components of this workplace. This IVW (interactive virtual world), automatically built using VRML combined with Java, is actualized on line with 3D models of the objects present in the real workplace. Internet interaction between any remote operator and the IVW is ensured by a Java based virtual interface and may be used, as well to teleoperate the robot. The presented approach is applied to PIONEER 2 and LABMATE mobile robots