Second-Order Hierarchical Fast Terminal Sliding Model Control for a Class of Underactuated Systems Using Disturbance Observer

Wei, Liu

doi:10.11648/j.acis.20190702.12

Cited by 3 publications

(2 citation statements)

References 26 publications

(34 reference statements)

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“…TD works well for practical engineering problems because it can extract the continuously filtered signal and its differential value from randomly noisy or discontinuous signal data [18]. In this paper, the nonlinear TD constructed using the hyperbolic tangent (HT) nonlinear function-based TD (HTTD) is utilized as follows: [20] ( )…”

Section: Figure 3 the Proposed LI Controller With The Additional Dist...mentioning

confidence: 99%

A Sensitive and Accurate Walking Speed Prediction Method Using Ankle Torque Estimation for a User-Driven Treadmill Interface

2022

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To achieve safe and immersive interface with a user-driven treadmill (UDT), robustness of the user position must be ensured by sensitively estimating and accurately converging to the intentional walking speed (IWS). The existing IWS estimation using a linear observer with the cart model (1 st order dynamics) can exponentially converge to the true IWS. However, when the estimation sensitivity is increased by increasing the gain, this method causes severe postural instability due to the generation of excessive anomalous forces. Thus, the existing method has an implicit limitation with regards to increasing the position robustness because of the postural instability issues. In this paper, to simultaneously achieve sensitive and accurate IWS estimation while reducing postural instability on a UDT, in addition to the cart model, we have also utilized the inverted pendulum-based gait model (IPGM) as a 2 nd order dynamic to estimate the intentional walking acceleration (IWA) generated by the ankle torque. Thus, the proposed IWS prediction method uses the cart model for accurate convergence to IWS and the IPGM to follow sensitively the change in the IWS. In the proposed method, the internal states of the existing observers applied to the 1 st and 2 nd order dynamics are shared recursively to estimate the ankle torque acting as a disturbance for the IPGM and to sensitively predict the change in the IWS. Experiments show that the proposed method can significantly facilitate the users in following a profile of desired walking speeds more accurately than the existing IWS estimation method under the same position robustness setup.

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Section: Figure 3 the Proposed LI Controller With The Additional Dist...mentioning

confidence: 99%

A Sensitive and Accurate Walking Speed Prediction Method Using Ankle Torque Estimation for a User-Driven Treadmill Interface

2022

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“…However, since the great properties of both hierarchical SM control strategy and FTSM control strategy, there is a desire to combine the benefits of both to obtain defined finite time convergence, chattering elimination and strong robust simultaneously. Abolvafaei and Ganjefar 27 and Liu et al 28 combined the FTSM surface with a linear sliding surface is used to design the hierarchical FTSM control strategy. By using the strategy, the advantages of two sliding mode surfaces can be obtained simultaneously.…”

Section: Introductionmentioning

confidence: 99%

A novel hierarchical nonlinear proportional-integral fast terminal sliding mode control for PMSM drives

Peng

Zhang

2021

Advances in Mechanical Engineering

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This study proposes a novel hierarchical nonlinear proportional-integral fast terminal sliding mode (HNLPIFTSM) control for permanent magnet synchronous motor (PMSM) speed regulation system. A new type of sliding surface called HNLPIFTSM surface, which combines the benefits of a nonlinear proportional-integral (PI) sliding mode surface and a fast terminal sliding mode (FTSM) surface, is proposed to enhance the robustness and improved the dynamic response, whilst preserving the great property of the conventional hierarchical fast terminal sliding mode (HFTSM) control strategy. The proposed HNLPIFTSM surface uses the novel nonlinear PI sliding mode surface as its inner loop and uses the FTSM surface as its outer loop. Meanwhile, an extended state observer (ESO) is used to estimate the uncertain terms of the PMSM speed regulation system. Furthermore, the stability of the closed-loop control system under the ESO and the HNLPIFTSM control strategy is proved by the Lyapunov stability theorem. Finally, the simulations and experimental demonstrations verify the effectiveness and superiorities of our proposed HNLPIFTSM control strategy over the conventional HFTSM control strategy.

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Control Scheme for Sideways Walking on a User-driven Treadmill

Pyo

Kim

Yoon

2022

2022 International Conference on Robotics and Automation (ICRA)

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Second-Order Hierarchical Fast Terminal Sliding Model Control for a Class of Underactuated Systems Using Disturbance Observer

Cited by 3 publications

References 26 publications

A Sensitive and Accurate Walking Speed Prediction Method Using Ankle Torque Estimation for a User-Driven Treadmill Interface

A Sensitive and Accurate Walking Speed Prediction Method Using Ankle Torque Estimation for a User-Driven Treadmill Interface

A novel hierarchical nonlinear proportional-integral fast terminal sliding mode control for PMSM drives

Control Scheme for Sideways Walking on a User-driven Treadmill

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