Advanced Control Schemes for Upper Limb Prosthesis pp. 377-408
Authors: (Stefan Herrmann, Klaus Buchenrieder, Universitat der Bundeswehr Munchen, Fakultat fur Elektrotechnk und Technische Informatik, Munich, Germany)
Abstract: Electronically controlled prostheses for the upper-extremity are used by patients with either above- or below-elbow amputations and are predominantly indicated for individuals who cannot use body-powered devices for their daily activities. To operate active prosthetic manipulators, patients must exhibit a minimal threshold myoelectric signal or be able to control a near-infrared signal from the remaining musculature and must possess the ability to willingly isolate respective contractions. Such muscle exertions are classified and mapped to prehensile hand- or arm-motion patterns to steer prosthetic manipulators. This chapter introduces the various facets of such control schemes for powered upper-limb prosthesis. As for the state-of-the-art, the material in this Chapter focuses on the acquisition and processing of myoelectric as well as near-infrared signals for steering the actuators of advanced hand- and arm-prosthesis. After a short introduction, tracing the developments and advancements of control schemes for prostheses, the acquisition of myoelectric and near-infrared signals is explained. This introductory part is followed by a brief description of basic control schemes, an overview of bioelectric signals as well as an explanation of instruments for signal acquisition. The section on transformations and signal processing steps, which must be performed to derive useful steering signals, provides a disquisition on standard features. The part on dimensionality reduction and classification techniques is followed by the presentation of effects which are due to muscle fatigue, that influence the acquired signals, and introduces methods for preterm detection and compensation thereof. Lastly, the 380 Buchenrieder, Herrmann Chapter closes with concluding remarks and provides directions for future research. Throughout the Chapter, concepts and practical applications are explained by using examples from past and references to ongoing research.