TESIS DOCTORAL - Robotics Lab - Universidad Carlos III de Madrid

9.2. Fear results 185In order to establish the limits of the secure area, the ideal wellbeing value (Wb ideal =100) and the activation levels for motivations (L d = 10) are considered. Since all drivessimultaneously evolve and several motivations can compete for the dominance, the securityarea width is set to 15. Consequently, it is considered that when the robot’s wellbeing isbetween 100 and 85, it is within the secure area.Table 9.2 shows the percentage of permanence within the secure area during the exploitingphase. As can be seen, when fear is included as a motivation, the wellbeing isalmost the 70% of iterations within the secure area, which represents a 5% more than whenfear is not used. This is coherent because fear is used to avoid dangerous states where therobot can be damaged. Once the robot is harmed, the wellbeing decreases enough to moveout the secure area.Table 9.2: Permanence at secure area during the exploiting sessionswithout fear with fear65% 69.5%Non dominant motivationMoreover, if there is not a dominant motivation, it means that all the internal needs andexternal stimuli are not strong enough to induce a behavior. Hence, it can be consideredthat the robot is in a comfortable situation. The percentage of time during the exploitingsessions that a dominant motivation does not exist proves how pleasant the robot’s “life” is.Table 9.3 shows that considering fear, the 78% of the time there is not dominant motivation.On the other hand, when the robot lives without fear, the percentage is reduced to 72%.Once again, these numbers show how fear provides a better quality of “life”.Table 9.3: Percentage without a dominant motivation during the exploiting sessionswithout fear with fear72.22% 78%Number of times the robot has been damagedThe differences of the previous percentage values could seem not very significant. However,it must be recalled that the number of negative interactions (the robot is hit or offended)is very low. During all experiments this only occurs for a low percentage of allinteractions with Alvaro. Therefore, the impact of fear in this scenario can not represent a