Mobius: An Omnidirectional Robotic Platform and Software Architecture for Network Teleoperation

The following thesis presents the results of a project to develop and test an omnidirectional robotic system (hardware and software) at NASA Langley Research Center's Robotics and Intelligent Machines Lab. The impetus for the project was the unique capabilities of omnidirectional systems. Some of the many potential benefits these systems have include improved material-handling capabilities in constrained environments (such as might be found in extraterrestrial manned habitats), efficient camera-based vehicle teleoperation, and simplified route planning for autonomous robot operations. The project's focus was to design, build, and test a system that used Mecanum wheels to achieve omnidirectional motion. In addition to the mobility considerations, the robot was designed from the start as a platform for testing a high-level software architecture for Internet-enabled teleoperation. The robot, named Mobius, uses a high-level processor running Linux to connect to wireless networks, process user-input data, relay camera imagery, and communicate with a low-level microcontroller. All the programs for user input and imagery viewing from the onboard cameras are cross-platform, Internet-enabled, client-server applications. Because of its wireless network capability, when the robot is within range of a wide-area-network wireless access point, it can be driven from an arbitrary location on the Internet. The low-level control of Mobius' motors is through a microcontroller-based fuzzy-logic algorithm. This algorithm combined with the methodology for user-input processing contributes to the robot's capabilities of smooth translation in any direction, bidirectional rotation, and simultaneous translation with rotation. In its final configuration, the robot performs admirably as a demonstration platform for Mecanum-wheel-based omnidirectional motion, and a number of tests were designed and executed to evaluate the performance of both the omnidirectional motion, and the performance of the camera-based teleoperation-control software architecture. Future work (another robot with a unique Mecanum wheel-configuration and autonomous algorithms capability) — is already in progress, and is briefly outlined with regard to the lessons learned from Mobius.