This work presents the kinematic and dynamic modeling of a human–wheelchair system which considers that its center of mass is not located in the middle of the wheel’s axle. Furthermore, a novel motion controller is presented for a human–wheelchair system, which is capable of performing positioning and path-following tasks in human-shared environments. This controller design is based on two cascaded subsystems: a kinematic controller, and a dynamic controller that compensates the dynamics of the human–wheelchair system. Additionally, an algorithm based on fuzzy-logic is proposed and incorporated in the aforementioned path-following control for pedestrian collision avoidance. This methodology considers to quantify heuristics social rules to make a balance between modulating velocity or direction during the avoidance. Three different interference cases, commonly found during walking events, are tested in a structured scenario. The experimental results demonstrate that the system is capable of overcoming many usual interference situations with human obstacles. A good performance of the path-following control is also verified.

Abstract.A total of 104 children aged between 41 and 47 months were selected to study the relationship between language and false belief understanding. Participants were assigned to four different training conditions: discourse, labelling, control (all with deceptive objects), and sentential complements (involving non-deceptive objects). Post-test results showed an improvement in children's false belief understanding in the discourse and the labelling conditions, but not in the sentential complements with non-deceptive objects or the control group. Furthermore, the most remarkable improvement in false belief understanding occurred in the labelling group. These results suggest that some types of linguistic experience promote the development of false belief understanding, provided that differing perspectives are confronted.

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