An Evaluation of Moreau’s Time-Stepping Scheme for the Simulation of a Legged Robot

International audienceA state-of-the-art simulation technique that solves the equations of motion together with the set-valued contact and impulse laws by the time-stepping scheme of Moreau is introduced to the legged robotics community. An analysis is given that shows which of the many variations of the method fits best to legged robots. Two different methods to solve the discretized normal cone inclusions are compared: the projected over-relaxed Jacobi and Gauss-Seidel iteration. The methods are evaluated for an electrically-driven quadrupedal robot in terms of robustness, accuracy, speed and ease of use. Furthermore, the dependence of the simulation speed on the choice of the generalized coordinates is examined. The proposed technique is implemented in C++ and compared to a fast and simple approach based on compliant contact models. In conclusion, the introduced method with hard contacts is very beneficial for the simulation of legged robots

<i>Pgi</i> allozyme allele and genotype frequencies in <i>Tigriopus californicus</i>.

a<p>Data from dates prior to 2004 were compiled from published and unpublished sources <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040035#pone.0040035-Burton1" target="_blank">[12]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040035#pone.0040035-Burton3" target="_blank">[14]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040035#pone.0040035-Ganz1" target="_blank">[18]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040035#pone.0040035-Burton5" target="_blank">[20]</a>.</p><p> <b>Deviations of samples (of size N) from Hardy-Weinberg proportions shown as </b><b><i>p</i></b><b>-value, non-significant or not-applicable.</b></p

ANYmal in the Field : Solving Industrial Inspection of an Offshore HVDC Platform with a Quadrupedal Robot

Offshore HVDC converter stations for transportation of offshore wind energy to the coast need regular human inspection. Automated surveillance of such a platform by a mobile robot has high potential of improving the speed and quality of decision-making while reducing operating expenses and risk of unmanned operation of the platforms. However, the challenging environment of such platforms has prevented operators from making use of mobile robots to this date. Recent progress in legged robotics resulted in systems that are becoming feasible for such tasks nowadays. For this reason, the quadrupedal robot ANYmal was tested on a platform in the North Sea for automated inspection. This paper presents the results of the field tests and discusses the challenges of industrial inspection of offshore sites.ISSN:2511-125

Practice Makes Perfect: An Optimization-Based Approach to Controlling Agile Motions for a Quadruped Robot

ISSN:1070-9932ISSN:1558-223

Towards a Generic Solution for Inspection of Industrial Sites

Autonomous robotic inspection of industrial sites offers a huge potential with respect to increasing human safety and operational efficiency. The present paper provides an insight into the approach taken by team LIO during the ARGOS Challenge. In this international competition, the legged robot ANYmal was equipped with a sensor head to perform visual, acoustic, and thermal inspection on an oil and gas site. The robot was able to autonomously navigate on the outdoor industrial facilty using rotating line-LIDAR sensors for localization and terrain mapping. Thanks to the superior mobility of legged robots, ANYmal can omni-directionally move with statically and dynamically stable gaits while overcoming large obstacles and stairs. Moreover, the versatile machine can adapt its posture for inspection. The paper additionally provides insight into the methods applied for visual inspection of pressure gauges and concludes with some insight into the general learnings from the ARGOS Challenge

ANYmal - toward legged robots for harsh environments

ISSN:0169-1864ISSN:1568-553