Design a Fall Recovery Strategy for a Wheel-Legged Quadruped Robot Using Stability Feature Space

In this paper, we introduced a conceptual analysis to select stability features when performing predefined and precise motions on robots. By analyzing the different stable poses named features and the possible transitions towards different ones, the introduced concept allows to design more predictable and suitable motions when performing particular tasks. As an example of how the concept can be applied we use it on the fall recovery of the quadruped robot CENTAURO. This robot, which is equipped with a custom hybrid wheel-legged mobility system, have good intrinsic stability as other quadrupeds. However, the characteristics of the rough terrains where it might be deployed require complex maneuvers to cope with possible strong disturbances. To prevent and more importantly recover from falls, realignment of postural responses will not be adequate, and effective recovery procedures should be developed. This paper introduces the details of how the presented conceptual analysis provides and an effective fall recovery routine for CENTAURO based on a state machine. The performance of the proposed approach is evaluated with extensive simulation trials using the dynamic model of the CENTAURO robot showing good effectiveness in recovering the robot after fall on flat and inclined surfaces

Support polygon in the hybrid legged-wheeled CENTAURO robot: modelling and control

Search for the robot capable to perform well in the real-world has sparked an interest in the hybrid locomotion systems. The hybrid legged-wheeled robots combine the advantages of the standard legged and wheeled platforms by switching between the quick and efficient wheeled motion on the flat grounds and the more versatile legged mobility on the unstructured terrains. With the locomotion flexibility offered by the hybrid mobility and appropriate control tools, these systems have high potential to excel in practical applications adapting effectively to real-world during locomanipuation operations. In contrary to their standard well-studied counterparts, kinematics of this newer type of robotic platforms has not been fully understood yet. This gap may lead to unexpected results when the standard locomotion methods are applied to hybrid legged-wheeled robots. To better understand mobility of the hybrid legged-wheeled robots, the model that describes the support polygon of a general hybrid legged-wheeled robot as a function of the wheel angular velocities without assumptions on the robot kinematics or wheel camber angle is proposed and analysed in this thesis. Based on the analysis of the developed support polygon model, a robust omnidirectional driving scheme has been designed. A continuous wheel motion is resolved through the Inverse Kinematics (IK) scheme, which generates robot motion compliant with the Non-Sliding Pure-Rolling (NSPR) condition. A higher-level scheme resolving a steering motion to comply with the non-holonomic constraint and to tackle the structural singularity is proposed. To improve the robot performance in presence to the unpredicted circumstances, the IK scheme has been enhanced with the introduction of a new reactive support polygon adaptation task. To this end, a novel quadratic programming task has been designed to push the system Support Polygon Vertices (SPVs) away from the robot Centre of Mass (CoM), while respecting the leg workspace limits. The proposed task has been expressed through the developed SPV model to account for the hardware limits. The omnidirectional driving and reactive control schemes have been verified in the simulation and hardware experiments. To that end, the simulator for the CENTAURO robot that models the actuation dynamics and the software framework for the locomotion research have been developed

Design and Experimental Evaluation of a Hybrid Wheeled-Leg Exploration Rover in the Context of Multi-Robot Systems

With this dissertation, the electromechanic design, implementation, locomotion control, and experimental evaluation of a novel type of hybrid wheeled-leg exploration rover are presented. The actively articulated suspension system of the rover is the basis for advanced locomotive capabilities of a mobile exploration robot. The developed locomotion control system abstracts the complex kinematics of the suspension system and provides platform control inputs usable by autonomous behaviors or human remote control. Design and control of the suspension system as well as experimentation with the resulting rover are in the focus of this thesis. The rover is part of a heterogeneous modular multi-robot exploration system with an aspired sample return mission to the lunar south pole or currently hard-to-access regions on Mars. The multi-robot system pursues a modular and reconfigurable design methodology. It combines heterogeneous robots with different locomotion capabilities for enhanced overall performance. Consequently, the design of the multi-robot system is presented as the frame of the rover developments. The requirements for the rover design originating from the deployment in a modular multi-robot system are accentuated and summarized in this thesis

Development of a Rat-like Robot and Its Applications in Animal Behavior Research

制度:新 ; 報告番号:甲3587号 ; 学位の種類:博士(工学) ; 授与年月日:2012/3/15 ; 早大学位記番号:新592

Sélection et contrôle de modes de déplacement pour un robot mobile autonome en environnements naturels

Le déplacement entièrement autonome d'un robot mobile en environnements naturels est un problème encore loin d'être résolu. Il nécessite la mise en oeuvre de fonctionnalités permettant de réaliser le cycle perception/décision/action, que nous distinguons en deux catégories : navigation (perception et décision sur le mouvement à réaliser) et locomotion (réalisation du mouvement). Pour pouvoir faire face à la grande diversité de situations que le robot peut rencontrer en environnement naturel, il peut être primordial de disposer de plusieurs types de fonctionnalités complémentaires, constituant autant de modes de déplacement possibles. En effet, de nombreuses réalisations de ces derniers ont été proposées dans la littérature ces dernières années mais aucun ne peut prétendre permettre d'exécuter un déplacement autonome en toute situation. Par conséquent, il semble judicieux de doter un robot mobile d'extérieur de plusieurs modes de déplacement complémentaires. Dès lors, ce dernier doit également disposer de moyens de choisir en ligne le mode le plus approprié. Dans ce cadre, cette thèse propose une mise en oeuvre d'un tel système de sélection de mode de déplacement, réalisée à partir de deux types de données : une observation du contexte pour déterminer dans quel type de situation le robot doit réaliser son déplacement et une surveillance du comportement du mode courant, effectuée par des moniteurs, et qui influence les transitions vers d'autres modes lorsque le comportement du mode actuel est jugé non satisfaisant. Ce manuscrit présente donc : un formalisme probabiliste d'estimation du mode à appliquer, des modes de navigation et de locomotion exploités pour réaliser le déplacement autonome, une méthode de représentation qualitative du terrain (reposant sur l'évaluation d'une difficulté calculée après placement de la structure du robot sur un modèle numérique de terrain), et des moniteurs surveillant le comportement des modes de déplacement utilisés (évaluation de l'efficacité de la locomotion par roulement, surveillance de l'attitude et de la conguration du robot...). Quelques résultats expérimentaux de ces éléments intégrés à bord de deux robots d'extérieur différents sont enfin présentés et discutés. ABSTRACT : Autonomous navigation and locomotion of a mobile robot in natural environments remain a rather open issue. Several functionalities are required to complete the usual perception/decision/action cycle. They can be divided in two main categories : navigation (perception and decision about the movement) and locomotion (movement execution). In order to be able to face the large range of possible situations in natural environments, it is essential to make use of various kinds of complementaryfunctionalities, defining various navigation and locomotion modes. Indeed, a number of navigation and locomotion approaches have been proposed in the litterature for the last years, but none can pretend being able to achieve autonomous navigation and locomotion in every situation. Thus, it seems relevant to endow an outdoor mobile robot with several complementary navigation and locomotion modes. Accordingly, the robot must also have means to select the most appropriate mode to apply. This thesis proposes the development of such a navigation/locomotion mode selection system, based on two types of data : an observation of the context to determine in what kind of situation the robot has to achieve its movement and an evaluation of the behavior of the current mode, made by monitors which inuence the transitions towards other modes when the behavior of the current one is considered as non satisfying. Hence, this document introduces a probabilistic framework for the estimation of the mode to be applied, some navigation and locomotion modes used, a qualitative terrain representation method (based on the evaluation of a diculty computed from the placement of the robot's structure on a digital elevation map), and monitors that check the behavior of the modes used (evaluation of rolling locomotion efficiency, robot's attitude and conguration watching. . .). Some experimental results obtained with those elements integrated on board two different outdoor robots are presented and discussed

Study on biped foot systems and controls adaptable to various terrains

制度:新 ; 報告番号:甲2842号 ; 学位の種類:博士(工学) ; 授与年月日:2009/3/15 ; 早大学位記番号:新506