Navegação reativa de robôs móveis com base no fluxo óptico

• Autor(a) principal: Caldeira, Eliete Maria de Oliveira
• Data de Publicação: 2002
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/4097
• topic: Engenharia Elétrica; Desvio de obstáculos; Fluxo óptico; Navegação de robôs móveis; Robôs móveis; Veículos autônomos; 621.3

This Ph. D. Thesis proposes to perform the navigation of mobile robots using a sensing system completely based on the optical flow which is calculated from a sequence of two images acquired by a camera fixed onboard the robot. To check the feasibility of using the proposed sensing system, a control system is designed to give the robot the capability of reacting to environmental changes, while executing the wander behavior with obstacle avoidance. The control system uses only data coming from the visual sensing system based on the optical flow. No modification is required to the robot’s environment, such as adding suitable textures or adjusting illumination. The optical flow is calculated considering that images are acquired when the robot is moving ahead with a null angular velocity. Then, a segmentation algorithm based on the optical flow field is proposed and implemented to detect distinct objects present in the scene. The distance from the robot to each object is then estimated based on the time to impact calculated from the optical flow field. The control system uses the time to impact corresponding to each object to determine a new direction to be followed by the robot. It then sends to the robot actuators the suitable commands to change the robot’s orientation. Both the sensing and control systems are implemented onboard a Pioneer 2-DX mobile robot and are used in a set of experiments, and the results show that the navigation system implemented presents very good performance.