Impedance control of a cable-driven series elastic actuator with the 2-DOF control structure

Zou, Wulin; Yang, Zhuo; Tan, Wen; Wang, Meng; Liu, Jingtai; Yu, Ningbo

doi:10.1109/iros.2016.7759515

Cited by 5 publications

(2 citation statements)

References 18 publications

(25 reference statements)

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“…The designed control utilized the function approximation and adaptive algorithm together to acquire the dynamics. A stabilizing 2-DOF control was proposed to separately realize the purpose of robustness and torque tracking [6]. By utilizing the good approximation ability of neuro networks and adaptive method, a new control scheme with neuro-adaptive observer was presented and studied [7].…”

Section: Introductionmentioning

confidence: 99%

A Novel Model-Free Robust Control of Cable-Driven Manipulators

et al. 2019

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A novel model-free robust control is developed for cable-driven manipulators in this work. Using the time-delay estimation (TDE) to estimate system dynamics, an attractive model-free structure is ensured. Then, a novel PID-nonsingular fast terminal sliding mode (PID-NFTSM) surface is proposed to achieve high control performance. Afterwards, a combined adaptive reaching law is designed to further enhance the control performance in the reaching phase. The developed control requires no system dynamics and is proper to apply under complex practical situations. At the same time, satisfactory comprehensive performance is still acquired thanks to the newly proposed PID-NFTSM surface and combined adaptive reaching law. Stability is proved through Lyapunov approach. Comparative simulation studies show that our control can provide better comprehensive performance than the recently reported PID-NFTSM control.INDEX TERMS Model-free, robust control, cable-driven manipulators, time-delay estimation (TDE), PID-nonsingular fast terminal sliding mode (PID-NFTSM).

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Section: Introductionmentioning

confidence: 99%

A Novel Model-Free Robust Control of Cable-Driven Manipulators

et al. 2019

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“…An effective solution, initially proposed by (Pratt and Williamson, 1995), is the series elastic actuator (SEA), in which elasticity is intentionally introduced in series between the motor and end-effector. This structure became increasingly popular during the last decades (Robinson et al, 1999;Yoo and Chung, 2015;Zou et al, 2016) for a number of advantages, such as great shock tolerance, safety, energy storage, accurate and smooth force output, etc. To detach the actuation motor from the end-effector and transmit torque to a distant place, the cable-driven SEA structure has been introduced into physical human-robot interaction (pHRI) systems.…”

Section: Introductionmentioning

confidence: 99%

Impedance control of a cable-driven SEA with mixed H₂/H_∞ synthesis

Yu¹,

Zou

2017

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Purpose: This paper presents an impedance control method with mixed H 2 /H ∞ synthesis and relaxed passivity for a cable-driven series elastic actuator to be applied for physical human-robot interaction.Design/methodology/approach: To shape the system's impedance to match a desired dynamic model, the impedance control problem was reformulated into an impedance matching structure. The desired competing performance requirements as well as constraints from the physical system can be characterized with weighting functions for respective signals. Considering the frequency properties of human movements, the passivity constraint for stable human-robot interaction, which is required on the entire frequency spectrum and may bring conservative solutions, has been relaxed in such a way that it only restrains the low frequency band. Thus, impedance control became a mixed H 2 /H ∞ synthesis problem, and a dynamic output feedback controller can be obtained.Findings: The proposed impedance control strategy has been tested for various desired impedance with both simulation and experiments on the cable-driven series elastic actuator platform. The actual interaction torque tracked well the desired torque within the desired norm bounds, and the control input was regulated below the motor velocity limit. The closed loop system can guarantee relaxed passivity at low frequency. Both simulation and experimental results have validated the feasibility and efficacy of the proposed method.Originality/value: This impedance control strategy with mixed H 2 /H ∞ synthesis and relaxed passivity provides a novel, effective and less conservative method for physical human-robot interaction control.

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