Control architecture and obstacle avoidance for acquiring the realtimeness

In this paper, under the assumption that a hybrid three-layer (deliberative, sequencing, reflexive) architecture is adopted, the structure of the reflexive layer is discussed. The reflexive layer consists of resources, actions, an action coordinator, and motion controller. To improve the real-time characteristics, a set of simplified actions and an action coordinator are designed using the functions provided in the RTAI (real-time application interface for Linux) environment. Also, an obstacle avoidance algorithm based upon data from a laser range scanner is developed. For the purpose of avoiding a moving obstacle that is treated as a moving circle through segmentation and circularization processes, a Kalman filter is developed to estimate the distance and orientation to the center of the moving circle. The effectiveness and real-time characteristics of the proposed reflexive layer and the developed algorithms are examined through avoidance experiments of scattered stand-still obstacles as well as a moving human.