Figure 2.

Control scheme of the Generalized Elastic Path Control combined with the conventional impedance control approach. The "Path Force Field" block constitutes a conservative force field and computes the torques τ_elast as a function of the actual joint angles q_act[53]. The corrective torques τ_cor of the "Impedance" block simulate a viscoelastic coupling of the actual angles q_act to the reference angles q_ref. The "torque-controlled drives" apply the desired torques to the Lokomat orthosis ("Orthosis"). These torques are measured as τ_sens. Together with the interaction torques τ_int, they move the exoskeleton and determine the actual angles q_act.