| dc.description.abstract | As the life expectancy of people is increasing and health care gets more expensive, a desire for assistive technologies in health care is growing. Such assistive technologies are researched and developed at the robotics lab of Eindhoven University Technology (TU/e) in the form of service robots. Research efforts are made to combine these robots with intelligent environments. An example of this is the research project described in this thesis. The idea is to have several service robots in an environment, such as a health care institution, and to have them controlled by a central control system. Therefore, a ubiquitous robotic framework for multi-robot planning and control is proposed in this thesis. This framework integrates with existing design efforts of the open-source robotics community. The main focus of this research project is on the planning module of the proposed system.
For such a multi-robot control system, a planning module is needed to handle the planning and scheduling of multiple tasks for the robots in an intelligent way. Therefore, the field of automated planning for robotic systems is analyzed first in this thesis. This is followed by a literature study on subjects ranging from automated planning, to Semantic Web and robotic technologies, such that all fields of ubiquitous robotics are covered. Based on the analysis and the literature study requirements are formed for the system. These requirements are then used to create the design of the framework. Furthermore, a prototype of the framework is implemented and experiments are performed with this prototype. The results of these experiments are evaluated. The thesis also includes a comparison between the proposed system and other similar planning systems as part of the discussion after the evaluation.
The design of the framework includes technologies such as Robot Operating System (ROS), Semantic Web Ontology languages (OWL and OWL-S), RoboEarth Cloud Engine (Rapyuta), and MIndiGolog, as they are innovative and provide genericness. MIndiGolog is a high-level agent programming language for multi-agent systems, and is based on situation calculus, a logic formalism designed for representing and reasoning about dynamic domains. MIndiGolog can reason over world states and transitions between states. In the proposed system, robots are also required to have a robot-type description available, whichs describe the specific robot capabilities of each connected robot, so that the planner can select the right robot for specific tasks. The planner searches for plans to accomplish user-given tasks.
The programming languages Python and Prolog are used to implement the prototype of the framework. PySWIP is used to query Prolog rules in Python. The prototype includes an executive layer, a planning layer and an ontology layer. This thesis focuses on the planning layer.
Several qualitative tests and an experiment with real robots are performed with the implemented prototype. The tests are performed to validate the functionality of the planning module of the system. The experiment describes a use case in which robots need to help with a cocktail party. In this use case, the robots need to take orders from guests, bring drinks to the guests, find empty drinks, and clean up empty glasses. The performed experiment however only includes the subtask of detecting empty drinks, due to limited time and resources. The robots need to navigate to the location where they expect empty drinks to be found and then perceive the empty drink.
The results of both the tests and the experiment are successful, as the tests performed as expected and the robots navigated to the nearest location where they expect empty drinks to be found in the experiment. There were however some performance issues with the communication interface of the system, including latency and bandwidth issues. Based on the results, the proposed framework is evaluated as a feasible approach to a ubiquitous robotic system for multi-robot planning and control. | |
