Modeling Hydra Behavior Using Methods Founded in Behavior-Based Robotics

Chapter 7Results and discussionIn this chapter the resulting behavioral model of Hydra is presented. The process of modelingthe overall behavior of Hydra was carried out in two steps: (1) Generation of theconstituent behaviors involved in Hydra’s overall behavior. Using the CSA, this amountsto defining an appropriate AC as well as a TF for each behavior. (2) Generation of thebehavioral organizer, i.e. organizing the constituent behaviors into layers, and definingthe interacting connections. The two steps were carried out independently of each other.This chapter starts with a presentation of the results concerning each of the constituentbehaviors, and concludes with a description of the overall behavior of the simulated Hydra.7.1 Generation of behaviorsThe four constituent behaviors of Hydra, as described in Section 5.1.3, were generated independentlyof each other. However, as mentioned in Section 6.1.1, the behavioral outputof B1-B3 share some characteristics, namely how Hydra should allocate its time betweencontracted and extended states, as well as in locomotion, depending on the animal’s motivationalstate. Thus, the transfer functions of B1-B3 share the task of evoking a CP or anLP, whichever is applicable, at the appropriate point in time, assuming that the particularbehavior is the active one.It should be noted that each behavior is a self-contained unit, operating only at a locallevel. Hence, a behavioral unit is not supplied with any information concerning the otherbehaviors included in the implemented behavior repertoire. It is therefore worth stressingthat, while the applicability clause of each behavior determines whether the output fromits transfer function should be active or not, the selection of which behavioral output thatis finally passed on to the actuators is carried out by the behavioral organizer. The resultsfrom the generation of the ACs as well as the TFs for each of the constituent behaviors in27