Takagi-Sugeno fuzzy model for knee joint angle control of paraplegic patients

In this paper, a feedback control has been developed, using functional electrical stimulation in order to control the movement of the leg of a paraplegic patient. The control design uses Takagi-Sugeno fuzzy models, which solves classes of nonlinear systems. The problem is described by linear matrix inequalities (LMI), reaching the specifications of stability according to Lyapunov theorem, decay rate and restriction on the input signal. The control system was designed to vary the knee joint angle from 0o to 45o by electrical stimulation of the quadriceps muscle. The feedback signal is related to the knee joint angle, stabilizing it at 45o.