Design and Development of a Rayleigh Oscillator-Based Reference Angle Generator for Motion Control of Smart Prosthetic Knees

Xu, Lei; Fu, Qiang

doi:10.1109/access.2020.2973858

Cited by 4 publications

(2 citation statements)

References 30 publications

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“…With the mathematical model built and the MR damper simulated, the FLPKME powered by CT + PD control algorithm could track the motions well and imitate the natural motions of a healthy human knee joint. Later, with the upgraded Rayleigh oscillator-based reference angle generator (RORAG) for motion control, the FLPKME could imitate the subject's knee joint's swing angle accurately in real time [43]. Based on FLPKME, Fu et al [44] further developed a two-bar linkage magnetorheological damper based lower limb prosthesis (MRLLP).…”

Section: Knee Prosthesismentioning

confidence: 99%

Medical applications of magnetorheological fluid: a systematic review

Liu¹,

Gao²,

Wang³

et al. 2022

Smart Mater. Struct.

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Magnetorheological (MR) fluid, whose rheological properties can be changed reversibly by applied magnetic field, offers superior capabilities and opportunities since its invention. The most crucial feature of MR fluid is its controllable and continuous yield stress. Taking this advantage, MR fluid is gaining popularity in various medical applications to meet their force/torque requirements. In this review article, progress of medical applications of MR fluid in the last two decades are systematically reviewed, mainly focused on six categories: lower limb prosthesis, exoskeleton, orthosis, rehabilitation device, haptic master, and tactile display. With MR fluid, natural and stable limb motions in lower limb prostheses, exoskeletons, and orthoses, flexible muscle trainings in rehabilitation devices, and high transparency and resolution haptic feedback can be realized. Relevant discussions and future perspectives are also provided.

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Section: Knee Prosthesismentioning

confidence: 99%

Medical applications of magnetorheological fluid: a systematic review

Liu¹,

Gao²,

Wang³

et al. 2022

Smart Mater. Struct.

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“…MR fluid is a smart material that mainly comprises carbonyl iron particles, carrier liquid, and some additives in a specific proportion [1]. The MR fluid can be transferred from ordinary newton-liquid state to solid state continuously and reversibly in milliseconds with or without magnetic fields, and its shear stress is related to the exerted magnetic field intensity [2], [3]. Due to its unique rheological properties, the MR fluid is widely employed in a variety of fields, such as bridges, buildings, vehicle suspensions, assistance orthoses, and robots [4], [5].…”

Section: Introductionmentioning

confidence: 99%

Development and Evaluation of a MR Damper With Enhanced Effective Gap Lengths

Feng

Tong

et al. 2020

IEEE Access

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Traditional magnetorheological (MR) damper featuring fixed gaps has the shortcomings of small damping force, single dynamic performance, and low adaptability. To overcome these shortcomings, a new MR damper with enhanced effective gap lengths is developed in this work, which achieves a double extension of the effective gap lengths via compactly integrating the conical fluid channels into the annular fluid channels. On the other hand, by altering the axial position of the valve spool controlled by a locking nut, the relative distance between the valve spool and piston of the MR damper is flexibly regulated; thus, the width of this adjustable gap in the conical fluid channels can be continuously adjusted. The magnetic circuit of the proposed MR damper is developed and its mechanical model is established as well to evaluate the dynamic performance. Sequentially, the finite element analysis (FEA) methodology is applied by using ANSYS/Emag software to investigate the changes of magnetic flux densities in these adjustable gaps. Moreover, a prototype is manufactured and experimental tests are conducted to verify its dynamic performance. The experimental results, under a fixed applied current, indicate that the damping force decreases with the increase of the adjustable gaps, and the maximum damping force reaches 7.2 kN at the adjustable gap of 0.6 mm. Besides, the dynamic range increases with the increase of the adjustable gap, and the dynamic range appears with a peak of 13.6. In addition, the damping force varies from 0.2 kN to 7.2 kN while the dynamic range attains 33 correspondingly by regulating the applied current and adjustable gap from 1.6 mm to 0.6 mm. From an experimental results perspective, the damping force and dynamic range can be not only effectively controlled by excitation current but also flexibly altered by regulating the width of the adjustable gaps simultaneously. Therefore, the dynamic performance of the proposed MR damper is also enhanced.

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Central pattern generator based on self-sustained oscillator coupled to a chain of oscillatory circuits

Kurkin

Kulminskiy

Ponomarenko

et al. 2022

Chaos: An Interdisciplinary Journal of Nonlinear Science

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We have proposed and studied both numerically and experimentally a multistable system based on a self-sustained Van der Pol oscillator coupled to passive oscillatory circuits. The number of passive oscillators determines the number of multistable oscillatory regimes coexisting in the proposed system. It is shown that our system can be used in robotics applications as a simple model for a central pattern generator (CPG). In this case, the amplitude and phase relations between the active and passive oscillators control a gait, which can be adjusted by changing the system control parameters. Variation of the active oscillator’s natural frequency leads to hard switching between the regimes characterized by different phase shifts between the oscillators. In contrast, the external forcing can change the frequency and amplitudes of oscillations, preserving the phase shifts. Therefore, the frequency of the external signal can serve as a control parameter of the model regime and realize a feedback in the proposed CPG depending on the environmental conditions. In particular, it allows one to switch the regime and change the velocity of the robot’s gate and tune the gait to the environment. We have also shown that the studied oscillatory regimes in the proposed system are robust and not affected by external noise or fluctuations of the system parameters. Moreover, using the proposed scheme, we simulated the type of bipedal locomotion, including walking and running.

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Design and Development of a Rayleigh Oscillator-Based Reference Angle Generator for Motion Control of Smart Prosthetic Knees

Cited by 4 publications

References 30 publications

Medical applications of magnetorheological fluid: a systematic review

Medical applications of magnetorheological fluid: a systematic review

Development and Evaluation of a MR Damper With Enhanced Effective Gap Lengths

Central pattern generator based on self-sustained oscillator coupled to a chain of oscillatory circuits

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