Digital controller design considering hardware constraints: application in a paraplegic patient

INTRODUCTION: A methodology was developed for implementing closed-loop control algorithms and for evaluating the behavior of a system, considering certain component restrictions used in laboratory implementation. METHODS: Mathematical functions representing a model of the biological system were used for knee extension/flexion movements. A Proportional Integral Derivative (PID) controller and another one using the root locus method were designed to control a patient’s leg position by applying functional electrical stimulation (FES). The controllers were simulated in Matlab and ISIS Proteus. After the simulations were performed, the codes were embedded in a microcontroller, and tests were conducted on a paraplegic volunteer. To the best of the authors’ knowledge, this is the first time that ISIS Proteus software resources have been used prior to implementing a closed-loop system designed to control the leg position of patients. RESULTS:This method obviates the application of initial controller tests directly to patients. The response obtained in the experiment with a paraplegic patient complied with the specifications set in terms of the steady-state error, the settling time, and the percentage overshoot. The proposed procedure was successfully applied for the implementation of a controller used to control the leg position of a paraplegic person by electrical muscle stimulation. CONCLUSION:The methodology presented in this manuscript can contribute to the implementation of analog and digital controllers because hardware limitations are typically not taken into account in the design of controllers.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Estadual Paulista Department of Electrical EngineeringLondrina State University Center of Technology and Urbanism Department of Electrical EngineeringUniversidade Estadual Paulista Department of Electrical Engineerin

Reattachment of an autogenous tooth fragment in a fracture with biologic width violation: A case report

An 11-year-old patient that fractured her maxillary left central incisor is presented. The fracture involved two thirds of the crown, compromising the pulp, and extended subgingivally on the palatal aspect, invading the biologic width. The procedure used to repair the fracture included flap surgery with a slight ostectomy and endodontic treatment. The reattachment of the tooth fragment and the restoration were performed with a bonding system and a resin composite. Examination 6 months after treatment revealed periodontal health, good esthetics, and normal function.33318118