چكيده به لاتين
Functional electrical stimulation with a history of more than forty years, is one of the most efficient and useful methods used to treat, rehabilitation motor and functional in people with injuries associated with upper motor neurons. Functional electrical stimulation uses pulses with low energy levels to induce involuntary and artificial contractions in the muscles of the injured limb.
Cycling induced by functional electrical stimulation has many physiological and psychological benefits for people with neurological impairments; the most important of these benefits are: improved cardiopulmonary function, increased blood circulation, increased muscle volume and strength, reduced skeletal muscle atrophy, reduced kidney and urinary tract infections, and improved sexual function.
The main novelty of this project is the propose a new control method for admittance control based on fuzzy-adaptive terminal sliding mode control. Features of this controller include finite time stability, online identification of the controlled system and finally no need to know the controlled system. It should be noted that the adaptive-fuzzy terminal sliding model controller proposed in this study simultaneously has the characteristics of robust and adaptive against disturbances and the patient's physiological condition; As the cadence is controlled by the patient's muscles and the admittance is controlled by the electric motor. In addition, in this research, for the first time, two new methods are proposed to determine the admittance filter coefficients, and also, a fuzzy controller is used so that the amplitude of the stimulation signal is determined appropriately and safely at any time.
First, the performance of the proposed control method for cadence and admittance control in virtual patient cycling was simulated. then, the two proposed procedures for selecting the admittance filter coefficients on this virtual system under three conditions of operation such as normal, fatigue effect and external disturbance was evaluated. The results of the simulation experiments show the superiority of the first procedure (average improvement 4% in torque tracking accuracy compared to the second procedure) in selecting the admittance filter coefficients.
In the experimental testbed, cadence and admittance control in cycling induced by functional electrical stimulation on three paraplegic individuals have been evaluated. In all experiments, the average of indirect torque, admitted cadence and cadence tracking errors are: 9.54 ± 0.51 %, 2.74 ± 0.49 % and 2.84 ± 0.49 %, respectively, which indicates excellent accuracy in tracking the admitted cadence and cadence as well as good accuracy in indirect tracking of the desired torque.
