Pain in child population is presented as a vital process which produces a variation in capacities and needs of care. That pain has an impact on the child's develpoment and therefore on his self-care agency acquisition. That is why the care provided to people with these characteristics are presented as a priority for the nursing professional. From a disciplinary framework, the nursing professional appears as a figue with knowledge for the development of new technological tools (such as robotics) to treat pain in children. In this way, a robotic system that incorporates a program for the assessment of pain in children has been designed using deductive methodology and guided by Software Requirements Specification ANSI/IEEE 830. Finally, this robotic system was implemented according to the construction phases of an Expert System.