RISE control for 2DOF human lower limb with antagonistic bi-articular muscles

This paper considers RISE control for two-degree-of-freedom (2DOF) human lower limb with antagonistic bi-articular muscles. The antagonistic bi-articular muscles straddle the waist joint and the knee joint in the lower limb. Because the nonlinear model of the lower limb of the human body is uncertain, a robust control method is developed yield semiglobal asymptotic tracking. Simulation results indicate that the torques in joint 2 of the 2DOF lower limb is lower than the previous method, because of antagonistic bi-articular muscles. It is verified that the 2DOF lower limb can move to the desired position in the presence of unmodeled bounded disturbances.