Autonomous planning for mobile manipulation services based on multi-level robot skills

General purpose service robots are expected to deal with many different tasks in unknown environments. The number of possible tasks and changing situations prevent developers from writing control programs for all tasks and possible situations. Complex robot tasks are thus accomplished by sequential execution of less complex robot actions that are triggered and configured by a task planner. The question of the appropriate abstraction level of robot actions is still being researched and not discussed conclusively. In this paper, we address the problem of atomicity of robot actions and provide some key properties that have to be considered while designing plan-based robot control systems. Based on these properties, we define and implement atomic skills of different abstraction level for the service robot TASER. The HTN planner JShop2 is used to complete the plan-based control architecture which is evaluated in a set of experiments.