Position Independent Control for Simultaneous FES of Biceps and Quadriceps Femoris

An approach for closed-loop control of the lower limb by combined FES of biceps and quadriceps is presented. The controller consists of two adaptive pole placement subcontrollers with nonlinear compensation acting on the same knee joint. The controller is able to handle correctly both single channel operation, for instance in the case of static signals, and simultaneous activation of the two muscle groups during transients. The controller behaves correctly for different positions of the test person.