Control of a robotic orthosis for gait rehabilitation

Assist-as-Needed Control of a Robotic Orthosis Actuated by Pneumatic Artificial Muscle for Gait Rehabilitation

“…This control performance is in accordance with the result achieved in [19][20][21][22] in which the 6-DOFs gait rehabilitation orthosis powered by PAMs is used, i.e., MTE < 15 • . However, the walking speed of the proposed system, i.e., 2.2 km/h, is lower than of its 6-DOF robot orthosis system counter part, i.e., 2.5 km/h.…”

“…However, the walking speed of the proposed system, i.e., 2.2 km/h, is lower than of its 6-DOF robot orthosis system counter part, i.e., 2.5 km/h. The trajectory tracking control strategy of 6-DOF system based on the boundary layer augmented sliding control (BASMC) law [19,20] and the chattering free robust variable structure controller (CRVC) [21,22], whereas the proposed system employed the modified computed torque control scheme with one more fractional order derivative for tracking purposed. Although, the nominal pressure is also used for AAN, the proposed strategy required less force sensors, i.e., 2 bar-shaped load cells attached at COM of thigh and shank part, in comparison with 4 load cells connected in series with each PAM in the 6-DOF robot system.…”

“…Thus, the applications of PAM in rehabilitation robotics field are growing despite the inherent drawbacks such as hysteresis, compressibility and time variance which yield extreme difficulties in constructing an accurate mathematical model. Various prototype systems have been developed in research centers [11][12][13][14][15][16][17][18][19][20][21][22]. To handle the nonlinear behavior of the PAM, a three-element model [23] based on the sliding mode control (SMC) has been considered as a good choice for tracking control of both single PAM [24] and robots powered by PAMs [14,15,[18][19][20].…”

“…Besides, AAN strategy which provides interactive human-robot gait training is also indispensable in these systems [20][21][22]. The AAN strategy can be achieved by compliance control in which the nominal pressure of the PAM is adjusted [17,[19][20][21][22].…”

Compliance adaptation of an intrinsically soft ankle rehabilitation robot driven by pneumatic muscles

“…Saglia et al presented an Ankle Rehabilitation roBOT (ARBOT) with two rotational DoFs driven by DC motors [7]. These stiff actuators along with trajectory tracking control scheme may produce large forces in response to the undesirable motions produced by position errors and may lead to secondary injuries to patients [8]. To tackle these problems, an impedance or admittance controller with proper stiffness and damping can be adopted to make the robot behaved with some compliant features [9,10].…”