Dynamics synchronization of the running of planar biped robots with SLIP model in stance phase

SLIP-Based Control of Bipedal Walking Based on Two-Level Control Strategy

“…In Fig. 9, the solid cyan lines depict ASLIP GRF profiles from the SLIP gait using control laws (17) and 20 dashed lines represent ATRIAS's desired GRFs in order to keep the torso upright using control law (25). Oscillations and deviations of the desired force profile from the ASLIP force profile are due to the attempts to keep torso equilibrium.…”

“…The controller aims to make the real robot follow the SLIP dynamics (specifically its GRF profile) and generate a stable walking gait. To have SLIP-like dynamics, ATRIAS uses torsional springs in series with the motors (note control methods like feedback linearization 14 are not possible because series-elastic actuation would cause a singularity in the control law 25 ). In this research, we use a force control that, given a known initial condition, will result in a leg GRF profile that brings the system back to the desired trajectory.…”

“…To ensure the swing toe clears the ground, we assume its height in mid-stance in (22) as y E mid = 0.06 m. For swing leg control (23), PID coefficients resulted by Newtonian optimization (24) using fmincon have the values of K P = 1033, K I = −66.2, K D = 69.5. The controller coefficients values in (25) to minimize torso angle error at the end of single-support phase are K F p = 0.6, K F d = 0.3 using a search algorithm.…”