Sound and complete reactive UAV behavior using constraint programming

Realizing autonomous behavior of UAVs is a complex endeavor. The behavior needs to be goal-directed (1), while adhering to safety constraints (2), and while dealing with contingency situations (3). A purely imperative approach is unsuitable for this purpose, since such approach is unable to manage the sheer complexity of the behavior, leading to erro- neous reactions to unforeseen situations in the environment, or situations that are simply not covered. In this paper, we present an innovative declarative approach to specify the autonomous behavior of UAVs. The approach combines a planning-based approach with constraint-programming for specifying safety and behavior constraints. The formal specification can be verified to be realizable. From the specification, we generate an execution policy, which can be proven to be sound and complete by construction if the specification is realizable. If the specification is not realizable, e.g., due to conflicting constraints, the generator indicates the source of the problem. We illustrate our approach on a case study that uses a UAV for air quality monitoring and show how the approach assists the developer to specify correct autonomous behavior. The resulting behavior is deployed on an on-board computer of a UAV and tested on the field.nrpages: 8status: publishe