Design and development of a novel omni-directional platform

Abstract

This thesis presents the design and development of a unique omni-directional platform\nknown as the Omnibot which was built in the Mechatronic and Robotic Systems\nLaboratory at UOIT. The Omnibot's layout is novel because its drive axes do not\nintersect with the geometric center of the body, which is typical for omni-directional\nplatforms using segmented omni-directional wheels. This design enables the center of\nmass to be lower in the design and increases the stability. A suspension system was\ndesigned for each of the four wheels to limit vibrations and to ensure contact between\nthe wheels and operating surface. The Omnibot was built to modularly support many\nsystems, including a robot arm, without altering the mechanical design of the frame.\nTwo control modes were developed: local and global. Commands to drive the Omnibot\ncan be received from either a joystick that can be directly interfaced with the\ncontroller or with commands that are sent from other systems that are either on or o \nof the Omnibot. Both control modes require encoder feedback to ensure commanded\nvelocities are being executed as specified. Global control requires feedback from an\nindoor localization system to determine the Omnibot's pose. Early implementation\nof the localization system is discussed. An open source robotics software, known as\nRobot Operating System (ROS) was selected for implementation of the Omnibot systems.\nROS serves as a middleware which allows components, such as the localization\nsystem and remote desktop, to communicate with each other through a decoupled\nmessaging system. ROS is modular and \nexible, allowing for easy adaptation of future\ncomponents. Test results of the Omnibot in operation are presented.