title: A New Controller for a Smart Walker Based on Human-Robot Formation.
abstract: This paper presents the development of a smart walker that uses a formation controller in its displacements. Encoders, a laser range finder and ultrasound are the sensors used in the walker. The control actions are based on the user (human) location, who is the actual formation leader. There is neither a sensor attached to the user's body nor force sensors attached to the arm supports of the walker, and thus, the control algorithm projects the measurements taken from the laser sensor into the user reference and, then, calculates the linear and angular walker's velocity to keep the formation (distance and angle) in relation to the user. An algorithm was developed to detect the user's legs, whose distances from the laser sensor provide the information necessary to the controller. The controller was theoretically analyzed regarding its stability, simulated and validated with real users, showing accurate performance in all experiments. In addition, safety rules are used to check both the user and the device conditions, in order to guarantee that the user will not have any risks when using the smart walker. The applicability of this device is for helping people with lower limb mobility impairments.
authors.affiliation: Postgraduate Program in Electrical Engineering, Federal University of Espirito Santo (UFES), Fernando Ferrari Av., 514, 29075-910 Vitoria, Brazil. carlos.valadao@aluno.ufes.br.
authors.forename: Carlos
authors.initials: C
authors.lastname: Valadão
authors.affiliation: Electrical Engineering Department, Federal University of Espirito Santo (UFES), Fernando Ferrari Av., 514, 29075-910 Vitoria, Brazil. eliete@ele.ufes.br.
authors.forename: Eliete
authors.initials: E
authors.lastname: Caldeira
authors.affiliation: Postgraduate Program in Electrical Engineering, Federal University of Espirito Santo (UFES), Fernando Ferrari Av., 514, 29075-910 Vitoria, Brazil. teodiano.bastos@ufes.br.
authors.forename: Teodiano
authors.initials: T
authors.lastname: Bastos-Filho
authors.affiliation: Postgraduate Program in Electrical Engineering, Federal University of Espirito Santo (UFES), Fernando Ferrari Av., 514, 29075-910 Vitoria, Brazil. anselmo@ele.ufes.br.
authors.forename: Anselmo
authors.initials: A
authors.lastname: Frizera-Neto
authors.affiliation: Institute of Automatics, National University of San Juan (UNSJ), San Mart&#237;n Av. (Oeste), 1109, J5400ARL San Juan, Argentina. rcarelli@inaut.unsj.edu.ar.|Consejo Nacional de Investigaciones Cient&#237;ficas y T&#233;cnicas (CONICET), C1425FQB Buenos Aires, Argentina. rcarelli@inaut.unsj.edu.ar.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Carelli
mesh_terms: D000465:Algorithms; D006801:Humans; D012371:Robotics / Q000295:instrumentation / Q000379:methods*; D016138:Walking / Q000502:physiology*
keywords: accessibility; assistive technology; mobility; robotic walker; smart walker