Active disturbance rejection for walking bipedal robots using the acceleration of the upper limbs

Abstract

SUMMARYA disturbance rejection controller is proposed based on the general dynamic model of 3D biped robots. For the first time, with this proposed approach, not only the Zero Moment Point (ZMP) location remains unchanged in presence of disturbances but also the longitudinal and lateral ground reaction forces and the vertical twist moment remain unchanged. This way, slipping as well as tipping is prevented by the controller. The swing phase of the robot's walking gait is considered. An integral sliding mode architecture is chosen for the disturbance rejection. The support forces and moments of the stance foot are the control outputs. The acceleration of the arm/body joints are chosen as the inputs. During the disturbance rejection, the leg joints remain at their desired trajectory. Since the leg joint trajectories are unaffected, the robot is still able to complete its step as planned, even when bounded disturbances are experienced. For simulations, the general method is applied to an 18-degree of freedom biped humanoid robot. Simulations show that the controller successfully mitigates bounded disturbances and maintains all of the support reactions extremely close to their desired values. Consequently, the shift in the position of the ZMP is negligible, and the robot foot does not slip.

Walking with perturbations: a guide for biped humans and robots

“…One commonly used approach in robotics in the context of slips is to introduce active disturbance rejection [321]. The latter used a "disturbance rejection controller" in conjunction with a general dynamic model of 3D biped robots.…”

“…A more natural compensation acts at the level of the trunk or arms, as proposed by some robotics authors [332,333]. Modified arm motion is also a feature of the approach taken by Hill and Fahimi [321]. These authors argued that compensation for a disturbance requires 2 steps: the robot must react to (compensate for) the disturbance, and then return to the desired gait.…”

Sliding Mode Tracking Control of a Wire-Driven Upper-Limb Rehabilitation Robot with Nonlinear Disturbance Observer

“…When delivering task-oriented rehabilitation training, the control scheme is required to assist the robot in guiding the paretic limb to finish predefined movements or trajectory accurately and compliantly. Linear control techniques such as PID (14, 15) and PD (15, 16) controllers have been designed for rehabilitation robot, but they have degraded performance if nonlinear uncertainties of the system are considered (17). Simple nonlinear control techniques such as robust torque control scheme (14, 15) and impedance control scheme (15, 18) cannot meet the requirement under uncertain dynamics.…”

“…Simple nonlinear control techniques such as robust torque control scheme (14, 15) and impedance control scheme (15, 18) cannot meet the requirement under uncertain dynamics. Many other control schemes have been presented such as fuzzy adaption (19) and adaptive control schemes (17, 18), whereas these control schemes perform well for industrial robots but not for rehabilitation robots due to uncertainties and disturbances in rehabilitation training (20). Sliding mode control (SMC) is a variable structure control method, which has inherent insensitivity and robustness against uncertainties and disturbances.…”

Chattering Free Sliding Mode Control of Upper-limb Rehabilitation Robot with Handling Subject and Model Uncertainties

“…Simple computed torque control은 느린응답이나 저크(Jerk)현상 때문에 Robust control이나 Passivity based robust control이 적용된 불확실성 모델을 다루기에는 유용하지 않고 특히 저크의 경우 환자 들에게 상해를 가할 위험이 있기 때문에 재활을 위한 로봇 제어에는 적합하지 않다 [10]. 이것들 외에 Factious gain [11], Fuzzy adaptation [12], Adaptive control [13,22] [10].…”