This paper is concerned with a control method of an exoskeletal ankle based on surface electromyographic (sEMG) signals. The sEMG signals of human ankle are introduced first. The muscles which are medial gastrocnemius(MG) and tibialis anterior(TA) are selected by experiments. Then a threshold method of controlling the exoskeletal ankle using sEMG signals is designed. A control system is realized. The sEMG signals are acquired, and sent to the computer. The computer deals with the sEMG signals and generates the control orders. The control orders are passed to the motor controller and drive the exoskeleton to move. At last, through experiment, the control method is verified and the effectiveness of the control system is proved.

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Chitin, extracted primarily from exoskeleton shellfish, is one of the most abundant biopolymer in the world. It is estimated to be produced annually almost as much as cellulose. The development of fishing activities in Morocco (coastline of 3500 km on both the Atlantic and the Mediterranean) induced an important fish industry waste. The aim of this work is to recover chitin, extracted from shellfish waste, and chitosan, produced by deacetylation of chitin, in the adsorption of organic pesticide 2,4-dichlorophenoxyacetate (2,4-D). The chitosan samples were prepared from α-chitin from crustacean shells and β-chitin from squid pens. The chitin deacetylation was carried out according to two methods using, respectively, as alkaline agent, the aqueous sodium hydroxide solution and anhydrous potassium hydroxide. The role of the source and of the process on the N-deacetylation reactions is confirmed. Characterization of chitin and chitosan was performed by infrared spectroscopy and nuclear magnetic resonance. The adsorption of 2,4-D by chitin and chitosan was performed at different pH values, the pesticide-adsorbent contact time and initial pesticide concentration. The adsorption is described by Langmuir-type isotherm and Freundlich-type isotherm. Recovery tests of 2,4-D confirm the initial interest in using chitin and chitosan as a depolluting agent.

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One of the principal guidelines in the design of haptic devices is to provide a suitable mechanical design that can improve control performance and the force-feedback fidelity. Unfortunately these guidelines may conflict with other design objectives (reflected mass, balancing, dexterity) as well as with specifications given by users and applications. For haptic interfaces based on tendon driven actuation it is highly important to achieve an accurate model of friction losses in the transmission system, in order to be able to compensate for them through an active control. In this paper it is reported a method for modeling and control complex tendon transmissions used for driving haptic devices and robots. The presented approach can operate in realtime with very low complexity; it is applicable to all kinds of serial manipulators and provides enough flexibility to allow identification of parameters and modeling of distributed friction phenomena all along the transmission. The approach has been implemented and tested on a 4 DOF exoskeleton system, the PERCRO L-EXOS.

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