TY - GEN
T1 - The design of robust phase oscillator for wearable robotic systems
AU - de la Fuente, Juan
AU - Subramanian, Susheelkumar C.
AU - Chinimilli, Prudhvi Tej
AU - Redkar, Sangram
AU - Sugar, Thomas
N1 - Funding Information:
This work was partially supported by the funding from DARPA Award # W911NF-15-1-0162 under Hip Exoskeleton for Superior Assistance Grant. We thank Dr. Kevin Hollander and Spring Active staff for their help in robot development and experimentation.
PY - 2019
Y1 - 2019
N2 - This paper presents the design of a phase-based robust oscillator for wearable robots that assists the human performing periodic or repetitive tasks. The robustness of the phase oscillator controller is evaluated by finding bounds for perturbations that guaranteed the stability of the output. Then, the Lyapunov redesign method is applied to construct a robust controller using a bounding function which can handle the uncertainties such as noise and perturbations in the overall human-robot system. The robust controller produces a bounded control signal to modify the amplitude and frequency of the resulting second-order oscillator to modulate the stiffness and damping properties. In this paper, the focus is put on the wearable robot that assists human hip joint while performing periodic activities such as walking. The proposed approach is verified through a simple pendulum experiment. The results show that a better limit cycle can be obtained with Lyapunov redesigned phase oscillator which controls the radial spread of the steady state. Finally, the potential of the proposed approach for hip assistance in a healthy subject wearing HeSa (Hip Exoskeleton for Superior Assistance) during periodic activities are discussed.
AB - This paper presents the design of a phase-based robust oscillator for wearable robots that assists the human performing periodic or repetitive tasks. The robustness of the phase oscillator controller is evaluated by finding bounds for perturbations that guaranteed the stability of the output. Then, the Lyapunov redesign method is applied to construct a robust controller using a bounding function which can handle the uncertainties such as noise and perturbations in the overall human-robot system. The robust controller produces a bounded control signal to modify the amplitude and frequency of the resulting second-order oscillator to modulate the stiffness and damping properties. In this paper, the focus is put on the wearable robot that assists human hip joint while performing periodic activities such as walking. The proposed approach is verified through a simple pendulum experiment. The results show that a better limit cycle can be obtained with Lyapunov redesigned phase oscillator which controls the radial spread of the steady state. Finally, the potential of the proposed approach for hip assistance in a healthy subject wearing HeSa (Hip Exoskeleton for Superior Assistance) during periodic activities are discussed.
KW - Periodic activity
KW - Phase oscillator
KW - Wearable robot
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U2 - 10.1115/DETC2019-97453
DO - 10.1115/DETC2019-97453
M3 - Conference contribution
AN - SCOPUS:85076500040
T3 - Proceedings of the ASME Design Engineering Technical Conference
BT - 43rd Mechanisms and Robotics Conference
PB - American Society of Mechanical Engineers (ASME)
T2 - ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2019
Y2 - 18 August 2019 through 21 August 2019
ER -