Nouveaux concepts de locomotion pour véhicules tout-terrain robotisés

Robotic ground vehicles are mechanisms that use gravity and contact forces with the ground to perform motion. They can either be wheeled, tracked or legged. In this thesis we will focus on n-wheeled vehicles able to perform ground following motion with all the wheels maintaining contact at the same time. The main goal of this work is to establish the implication of the topological architecture of the vehicle mechanism on criteria such as climbing skills, robustness, ground clearance, weight, power consumption, and price. Efficient tools will be provided to help the robot designer to understand the implications of important design parameters like the number of wheels, the vehicle mechanism, and the motorisation of joints on the above criteria. The general state of a robotic ground vehicle can be described using spatial vectors containing both the linear and angular components of physical quantities such as position, velocity, acceleration and linear force. By definition, there is motion when the vehicle's link velocity state vector (expressed from the ground reference) is greater than zero. Wheeled ground following motion is then a special case of vehicle constrained motion where all wheels maintain contact with the ground. This thesis will describe a general kinematic and dynamic analysis of n-wheeled ground following robots. We will then discuss "contact forces optimisation techniques" and show the relationship between the number of wheels of a vehicle mechanism, the topological structure and the optimised degrees of fredom that we can get for the contact forces distribution. We will conclude with some considerations concerning the sensors needs for on-board terrain estimation. We will emphasise our argument using our two robot designs as examples: Shrimp: A 6-wheeled ground vehicle based on a 3 DOF passive suspension mechanism. With this design, no sensor based control is necessary to maintain ground contact with all the wheels. The distribution of tangential contact forces is done passively but can be optimised with on board active control and sensors for contact properties estimation (gyro, joint position sensors). Octopus: A 8-wheeled ground vehicle based on a (6 DOF active + 1 DOF passive) suspension mechanism. The autonomous coordination of the active 14 DOF is based on the on-board integration of inclinometer, joint position sensors and tactile wheels able to sense ground contact properties (angle, curvature, force, ...). With this design, active control can distribute the contact forces to minimise tangential forces and increase traction. This decreases the need for friction to climb obstacles. The theoretical investigation and new sensing concepts enable the design these two robots that demonstrate excellent capabilities for rough terrain. Passive Wheeled Locomotion Mechanisms (WLM) solutions are now mature enough for real applications like space exploration. However, active WLM solutions demonstrate potential climbing skills that cannot be equalled passively. Enhanced integration of sensors, actuators and advanced embedded control algorithms will lead to greater applications for future field and service robotics applications

Design of a rescue robot for search and mapping operation

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2006Includes bibliographical references (leaves: 65-66)Text in English; Abstract: Turkish and Englishx, 76 leavesThe aim of this thesis is to design a mobile robot for rescue operations after an earthquake. The robot is designed to locate injured victims and life triangle in debris, to create a map of the disaster area and to collect the necessary information needed by digging and support robots in order to the database center. This robot enables us to rescue the victim in the shortest time with minimum injury. This will let us risking the lives of the rescue teams much less as well as rescuing much more victim alive.Robot is designed with the longitudinal body design. Shock absorber system gives the damper effect against falls as well as adding advanced equilibrium properties while passing through a rough land. Driving mechanism is a tracked steering system.Front and back arm system is developed to provide high mobility while overtaking the obstacles.Secondly hovercraft type robot, which works with the cushion pressure principle, is designed as a rescue robot. It is thought that if the adequate height is supplied, the robot could manage to overcome obstacles.As a third design, ball robot, which could easily move uphill and has a capability to overrun obstacles, is studied.Jumping mechanism will be working by magnetic piston.In addition robot is equipped with the sensors so that it has capable of the navigation. In order to achieve feasible sensor systems, all electronic components are evaluated and the most effective sensors are chosen

Modelling and Simulation of a Two wheeled vehicle with suspensions by using Robotic Formalism

International audienceModels, simulators and control strategies are required tools for the conception of secure and comfortable vehicles. The aim of this paper is to present an efficient way to develop models for dynamic vehicle, focusing on a two wheeled vehicles whose body involves six degrees of freedom. The resulting model is sufficiently generic to perform simulation of realistic cornering and accelerating behavior in various situations. It may be used in the context of motorcycle modeling, but also in various situations (e.g. for control application) as simplified model for 3 or 4 wheeled (tilting) cars. The approach is based on considering the vehicle as a multi-body poly-articulated system and the modeling is carried out using the robotics formalism based on the modified Denavit-Hartenberg geometric description. In that way, the dynamic model is easy to implement and the system can be used for control applications

Modelling and Simulation of a Two wheeled vehicle with suspensions by using Robotic Formalism

International audienceModels, simulators and control strategies are required tools for the conception of secure and comfortable vehicles. The aim of this paper is to present an efficient way to develop models for dynamic vehicle, focusing on a two wheeled vehicles whose body involves six degrees of freedom. The resulting model is sufficiently generic to perform simulation of realistic cornering and accelerating behavior in various situations. It may be used in the context of motorcycle modeling, but also in various situations (e.g. for control application) as simplified model for 3 or 4 wheeled (tilting) cars. The approach is based on considering the vehicle as a multi-body poly-articulated system and the modeling is carried out using the robotics formalism based on the modified Denavit-Hartenberg geometric description. In that way, the dynamic model is easy to implement and the system can be used for control applications

Development of an autonomous mobile robot with planning and location in a structured environment

Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do ParanáWith the advance of technology mobile robots have been increasingly applied in the industry, performing repetitive work with high performance, and in environments that pose risks to human health. The present work plans and develops a mobile robot platform for the micromouse competition. The micromouse consists of a small autonomous mobile robot that, when placed in an unknown labyrinth, is able to map it, search for the best path between the starting point and the goal and travel it in the shortest possible time. To accomplish these tasks, the robot must be able to self-locate, map the maze as it traverses it and plan paths based on the map obtained. The developed self-localization method is based on the odometry, the laser sensors present in the robot and on a previous knowledge of the start point and the configuration of the environment. Several methodologies of locomotion in unknown environment and route planning are analyzed in order to obtain the combination with the best performance. In order to verify the results, the present work is developed in real environment, in 3D simulation and also with a hardware in the loop capability. Labyrinths from previous competitions are used as basis for comparing methodologies and validating results. At the end it presents the algorithm capable of fulfilling all the requirements of the micromouse competition together with the results of its evaluation run.Com o avanço da tecnologia, os robôs móveis têm sido cada vez mais aplicados na indústria, realizando trabalhos repetitivos com alto desempenho e em ambientes que expõem riscos à saúde humana. O presente trabalho planeja e desenvolve um robô móvel para a competição micromouse. O micromouse consiste em um pequeno robô autônomo que, ao ser colocado em um labirinto desconhecido, é capaz de mapeá-lo, procurar o melhor caminho entre o ponto de partida e o objetivo, e percorrê-lo no menor tempo possível. Para realizar estas tarefas, o robô deve ser capaz de se auto-localizar, mapear o labirinto enquanto o percorre e planejar caminhos com base no mapa obtido. O método de auto-localização desenvolvido baseia-se na odometria, nos sensores a laser presentes no robô e em um prévio conhecimento do ponto de início e da configuração do ambiente. Diversas metodologias de locomoção em ambiente desconhecido e planejamento de rotas são analisadas buscando-se obter a combinação com o melhor desempenho. Para averiguação de resultados o presente trabalho desenvolve-se em ambiente real e em simulação 3D com hardware in the loop. Labirintos de competições anteriores são utilizados de base para o comparativo de metodologias e validação de resultados. Ao final apresenta-se o algoritmo capaz de cumprir todas as exigências da competição micromouse juntamente com os resultados em sua corrida de avaliação

Localization And Mapping Of Unknown Locations And Tunnels With Unmanned Ground Vehicles

The main goals of this research were to enhance a commercial off the shelf (COTS) software platform to support unmanned ground vehicles (UGVs) exploring the complex environment of tunnels, to test the platform within a simulation environment, and to validate the architecture through field testing. Developing this platform will enhance the U. S. Army Engineering Research and Development Center’s (ERDC’s) current capabilities and create a safe and efficient autonomous vehicle to perform the following functions within tunnels: (1) localization (e.g., position tracking) and mapping of its environment, (2) traversing varied terrains, (3) sensing the environment for objects of interest, and (4) increasing the level of autonomy of UGVs available at the ERDC. The simulation experiments were performed in the STAGE Simulator, a physics-based multi-scale numerical test bed developed by Robotic Operating System (ROS). Physical testing was conducted in Vicksburg, MS using a Coroware Explorer. Both the simulation and physical testing evaluated three SLAM algorithms, i.e., Hector SLAM, gMapping, and CORESLAM to determine the superior algorithm. The superior algorithm was then used to localize the robot to the environment and autonomously travel from a start location to a destination location. Completion of this research has increased the ERDC’s level of autonomy for UGVs from tether to tele-operated to autonomous