Bio-inspired standing balance controller for a full-mobilization exoskeleton

Bioinspired Postural Controllers for a Locked-Ankle Exoskeleton Targeting Complete SCI Users

“…The sole is 227 mm long, which corresponds to a maximum range of movement of 242 mm for the contact point, when the sole is rolling on the floor. The top part of the exoskeleton foot is tilted forward by 5 • , so when the middle of the foot is in contact with the floor, the shank axis has a 5 • angle with respect to the vertical axis (Baud et al, 2019). The soles are covered with a rubber layer, to prevent slippage when standing.…”

“…Drawing inspiration from this human sensorimotor adaptation, a novel postural position controller has been implemented and tested on TWIICE with no user (Baud et al, 2019 ). This controller regulated the balance with a proportional-derivative (PD) controller, acting on the angle of the knee, and fed with the estimated CoM position ( Figure 1C ).…”

“…The elevation angle of the thigh and trunk segments are computed from the estimated foot elevation angle and the joints encoders angles. Instead of using the trunk IMU as in Baud et al ( 2019 ), the IMU located in the left foot is used instead. It is expected to increase the performance for two reasons.…”

“…The “Baseline Knee Controller” (BKC) regulates the balance with a proportional-derivative (PD) controller, setting the angle of the knee, and fed with the CoM position ( Figure 2 ). This “Baseline Knee Controller” was described, simulated and experimentally tested (Baud et al, 2019 ). The knees are flexed proportionally to the estimated position of the CoM.…”

“…Simulations have been performed with the same Simulink simulation environment described in Baud et al ( 2019 ). The goal of this model is to check the proper operation of the controller, i.e., keeping the body standing without falling.…”