Robust Adaptive Impedance Control With Application to a Transfemoral Prosthesis and Test Robot

Azimi, Vahid; Fakoorian, Seyed Abolfazl; Nguyen, Thang; Simon, Daniel J.

doi:10.1115/1.4040463

Cited by 16 publications

(25 citation statements)

References 52 publications

(107 reference statements)

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“…To solve these limitations, APK, as a lower limb prosthesis, has drawn increasing research interests to help people deal with walking disabilities in the past years. Compared to a conventional passive prosthesis that has the shortcomings of inability to generate mechanical power and the lack of sensory feedback, APK improves the similarity of able-bodied gait, decreases hip work production, and reduces metabolic expenditure [4]. The active prosthesis is different from the passive prosthesis basically by the use of active components for locomotion assistance.…”

Section: Introductionmentioning

confidence: 99%

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Adaptive Robust Force Position Control for Flexible Active Prosthetic Knee Using Gait Trajectory

et al. 2020

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Active prosthetic knees (APKs) are widely used in the past decades. However, it is still challenging to make them more natural and controllable because: (1) most existing APKs that use rigid actuators have difficulty obtaining more natural walking; and (2) traditional finite-state impedance control has difficulty adjusting parameters for different motions and users. In this paper, a flexible APK with a compact variable stiffness actuator (VSA) is designed for obtaining more flexible bionic characteristics. The VSA joint is implemented by two motors of different sizes, which connect the knee angle and the joint stiffness. Considering the complexity of prothetic lower limb control due to unknown APK dynamics, as well as strong coupling between biological joints and prosthetic joints, an adaptive robust force/position control method is designed for generating a desired gait trajectory of the prosthesis. It can operate without the explicit model of the system dynamics and multiple tuning parameters of different gaits. The proposed model-free scheme utilizes the time-delay estimation technique, sliding mode control, and fuzzy neural network to realize finite-time convergence and gait trajectory tracking. The virtual prototype of APK was established in ADAMS as a testing platform and compared with two traditional time-delay control schemes. Some demonstrations are illustrated, which show that the proposed method has superior tracking characteristics and stronger robustness under uncertain disturbances within the trajectory error in ± 0 . 5 degrees. The VSA joint can reduce energy consumption by adjusting stiffness appropriately. Furthermore, the feasibility of this method was verified in a human–machine hybrid control model.

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Section: Introductionmentioning

confidence: 99%

“…More recently, a robust adaptive impedance method based on the nonscalar boundary layer and sliding surface for tracking knee angle is proposed [4], which overcomes the influence of parametric and nonparametric uncertainties. However, to achieve adequate joint trajectory tracking control, a precise robot dynamic model is required.…”

Section: Introductionmentioning

confidence: 99%

Adaptive Robust Force Position Control for Flexible Active Prosthetic Knee Using Gait Trajectory

et al. 2020

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“…27 However, they have neglected to include the impedance characteristics of walking in the design of the control system, 27 and no flexible mechanism has been included in their design. In another work, Azimi et al 28 have designed a robust model reference adaptive impedance control (RMRAIC) scheme for an active knee prosthesis. In that work, the control scheme was designed for the knee joint and the amputated place simultaneously.…”

Section: Introductionmentioning

confidence: 99%

“…Accordingly, full feedback of state variables is required to implement the control law. 28 Though the design in ref. [28] is promising, a shortcoming of the developed controller is the isolation of control scheme and the reference impedance model.…”

Section: Introductionmentioning

confidence: 99%

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A Novel Robust Model Reference Adaptive Impedance Control Scheme for an Active Transtibial Prosthesis

Heidarzadeh¹,

Sharifi²,

Salarieh³

et al. 2019

Robotica

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SummaryIn this paper, a novel robust model reference adaptive impedance control (RMRAIC) scheme is presented for an active transtibial ankle prosthesis. The controller makes the closed loop dynamics of the prosthesis similar to a reference impedance model and provides asymptotic tracking of the response trajectory of this impedance model. The interactions between human and prosthesis are taken into account by designing a second-order reference impedance model. The proposed controller is robust against parametric uncertainties in the nonlinear dynamic model of the prosthesis. Also, the controller has robustness against bounded uncertainties due to unavailable ground reaction forces and unmeasurable feedbacks of accelerations at the socket place. Moreover, an appropriate Series Elastic Actuator (SEA) mechanism for the prosthetic ankle is included in this work and its effects are discussed. Tracking performance and stability of the closed-loop system are proven via the Lyapunov stability analysis. Using simulations on an overall amputee prosthetic foot system, the effectiveness of the proposed RMRAIC controller is investigated for the task of level ground walking.

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Position‐based force tracking adaptive impedance control strategy for robot grinding complex surfaces system

Wang

Zhu

et al. 2023

Journal of Field Robotics

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As a key technology of robot grinding, force control has great influence on grinding effects. Based on the traditional impedance control, a position‐based force tracking adaptive impedance control strategy is proposed to improve the grinding quality of aeroengine complex curved parts, which considers the stiffness damping environmental interaction model, modifies the reference trajectory by a Lyapunov‐based approach to realize the adaptive grinding process. In addition, forgotten Kalman filter based on six‐dimensional force sensor is used to denoise the force information and a three‐step gravity compensation process including static base value calculation, dynamic zero update and contact force real‐time calculation is proposed to obtain the accurate contact force between tool and workpiece in this method. Then, to verify the effectiveness of the proposed method, a simulation experiment which including five different working conditions is conducted in MATLAB, and the experiment studying the deviation between the reference trajectory and the actual position is carried out on the robot grinding system. The results indicate that the position‐based force tracking adaptive impedance control strategy can quickly respond to the changes of environmental position, reduce the fluctuation range of contact force in time by modifying the reference trajectory, compensate for the defect of the steady‐state error of the traditional impedance control strategy and improve the surface consistency of machined parts.

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Robust Adaptive Impedance Control With Application to a Transfemoral Prosthesis and Test Robot

Cited by 16 publications

References 52 publications

Adaptive Robust Force Position Control for Flexible Active Prosthetic Knee Using Gait Trajectory

Adaptive Robust Force Position Control for Flexible Active Prosthetic Knee Using Gait Trajectory

A Novel Robust Model Reference Adaptive Impedance Control Scheme for an Active Transtibial Prosthesis

Position‐based force tracking adaptive impedance control strategy for robot grinding complex surfaces system

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