Repetitive Control Applied to a Social Robot for Interaction with Autistic Children

N-MARIA (New-Mobile Robot for Interaction with Autistics) is a robot developed at the Federal University of Espirito Santo (UFES/Brazil) to assist and interact with autistic children. This Child-Robot Interaction (CRI) is conveyed through different controllers, such as orientation and position controller, leader-follower formation controller, Repetitive Controller (RC), and RC plus Proportional-Integral (PI) controller. This work presents firstly the use of a repetitive controller, and then uses the RC plus the PI controller to implement a “play” mode to be played during a CRI. In this mode, a periodic setpoint is used to allow the robot to approach and move away from the child. Using the RC for this mode, the robot is able to follow the generated trajectory with small error, even with periodic setpoints. When using RC plus PI, the experiments show smaller tracking error.