Exploring the Tactor Configurations of Vibrotactile Feedback Systems for Use in Lower-Limb Prostheses1

Vibrotactile feedback may be able to compensate for the loss of sensory input in lower-limb prosthesis users to improve the mobility function. Designing an effective vibrotactile feedback system requires that users are able to perceive and respond to vibrotactile stimuli correctly and in a timely manner. Our study explored four key tactor configuration variables (i.e., tactors’ prosthetic layer, vibration intensity, prosthetic pressure, and spacing between adjacent tactors) through two experiments. The vibration propagation experiment investigated the effects of tactor configurations on vibration amplitude at the prosthesis–limb interface. Results revealed a positive relationship between vibration amplitude and intensity and a weak relationship between vibration amplitude and prosthetic pressure. Highest vibration amplitudes were observed when the tactor was located on the inner socket layer. The second experiment involving a sample of ten able-bodied and three amputee subjects investigated the effects of tactor configurations on user perception measured by response time, accuracy identifying tactors’ stimulation patterns, and spatial error in locating the tactors. Results showed that placing the tactors on the inner socket layer, greater spacing between adjacent tactors, and higher vibration intensity resulted in better user perception. The above findings can be directly applied to the design of vibrotactile feedback systems to increase the user response accuracy and decrease the response time required for dynamic tasks such as gait. They can also help to inform future clinical trials informing the optimization of tactor configuration variables.

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Examination of Tactor Configurations for the Design of Vibrotactile Feedback Systems for Use in Lower-Limb Prostheses

Volume 8: 30th Conference on Mechanical Vibration and Noise ◽

10.1115/detc2018-85197 ◽

2018 ◽

Cited By ~ 2

Author(s):

Sam Shi ◽

Matthew J. Leineweber ◽

Jan Andrysek

Keyword(s):

Lower Limb ◽

Negative Relationship ◽

Feedback System ◽

Elevated Pressure ◽

Intensity Level ◽

Response Accuracy ◽

Feedback Systems ◽

Vibrotactile Feedback ◽

Lower Limb Prosthesis ◽

Lower Limb Prostheses

Vibrotactile feedback may be able to compensate for the loss of sensory input in lower-limb prosthesis users. Designing an effective vibrotactile feedback system would require that users could perceive and correctly respond to vibrotactile stimuli applied by the tactors. Our study explored three key tactor configuration variables (i.e. vibratory intensity, prosthetic pressure, spacing between adjacent tactors) through two experiments. The vibration propagation experiment investigated the effects of tactor configurations on vibratory amplitude at the prosthesis-limb interface. Results revealed a positive relationship between vibratory amplitude and intensity, and a negative relationship between vibratory amplitude and prosthetic pressure. The vibrotactile perception experiment investigated the effects of tactor configurations on user response accuracy, and found that greater spacing between tactors, and higher prosthetic pressure resulted in more accurate responses from the subjects. These findings inform the design of a vibrotactile feedback system for use in lower-limb prostheses: 1) the tactors may be best placed in areas of slightly elevated pressure at the prosthesis-limb interface; 2) a higher vibratory intensity level should improve performance for vibrotactile feedback systems; and 3) more spacing between adjacent tactors improves user response accuracy.

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Optimal Model Reference Control Scheme Design for Nonlinear Strict-Feedback Systems

Engineering and Technology Journal ◽

10.30684/etj.v38i9a.1339 ◽

2020 ◽

Vol 38 (9A) ◽

pp. 1342-1351

Author(s):

Musadaq A. Hadi ◽

Hazem I. Ali

Keyword(s):

Reference Model ◽

Feedback System ◽

Optimization Method ◽

Feedback Systems ◽

Model Reference ◽

Scheme Design ◽

Model Reference Control ◽

Control Scheme ◽

Lyapunov Stability Analysis ◽

Strict Feedback

In this paper, a new design of the model reference control scheme is proposed in a class of nonlinear strict-feedback system. First, the system is analyzed using Lyapunov stability analysis. Next, a model reference is used to improve system performance. Then, the Integral Square Error (ISE) is considered as a cost function to drive the error between the reference model and the system to zero. After that, a powerful metaheuristic optimization method is used to optimize the parameters of the proposed controller. Finally, the results show that the proposed controller can effectively compensate for the strictly-feedback nonlinear system with more desirable performance.

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Vibrotactile Feedback System from the Fingertip to the Temples for Perceptual Enhancement of Contracture Palpation

IEEE Transactions on Haptics ◽

10.1109/toh.2021.3076501 ◽

2021 ◽

pp. 1-1

Author(s):

Kazuhiro Niwa ◽

Yoshihiro Tanaka ◽

Kota Kitamichi ◽

Takumi Kuhara ◽

Kimihiro Uemura ◽

...

Keyword(s):

Feedback System ◽

Vibrotactile Feedback

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The design and evaluation of a multi-sensory vibrotactile feedback system for a myoelectric prosthetic hand

International Journal of Biomechatronics and Biomedical Robotics ◽

10.1504/ijbbr.2011.043750 ◽

2011 ◽

Vol 1 (4) ◽

pp. 225 ◽

Cited By ~ 1

Author(s):

Edward D. Sellers ◽

Alan W.L. Chiu

Keyword(s):

Feedback System ◽

Prosthetic Hand ◽

Vibrotactile Feedback

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Criteria for Recovery of Zero Initial Condition Responses of Unstable Plants Under Input Saturation

10.1115/imece2000-2341 ◽

2000 ◽

Author(s):

Wei Wu ◽

Suhada Jayasuriya

Keyword(s):

Initial Conditions ◽

Input Saturation ◽

Input Sequence ◽

Feedback System ◽

Open Loop ◽

Feedback Systems ◽

Bounded Control ◽

Analysis And Design ◽

Study Results ◽

Unstable Plant

Abstract In this paper, we consider the sufficient and/or necessary conditions under which responses of unstable plants with zero initial conditions would be bounded under step inputs. Several possible unstable pole patterns are examined, and corresponding criteria are derived. It is shown that an unstable plant can be stabilized to have bounded responses using an alternate step input sequence. Step inputs simulate the saturated inputs in a feedback system with bounded control, where the closed-loop stability of an unstable plant is really difficult to study. Results from this open-loop study may lend some insight into the analysis and design of such feedback systems under input saturation nonlinearities.

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A Haptic Feedback System for Lower-Limb Prostheses

IEEE Transactions on Neural Systems and Rehabilitation Engineering ◽

10.1109/tnsre.2008.920075 ◽

2008 ◽

Vol 16 (3) ◽

pp. 270-277 ◽

Cited By ~ 77

Author(s):

R.E. Fan ◽

M.O. Culjat ◽

Chih-Hung King ◽

M.L. Franco ◽

R. Boryk ◽

...

Keyword(s):

Lower Limb ◽

Haptic Feedback ◽

Feedback System ◽

Lower Limb Prostheses

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A New Sensory Feedback System for Lower-Limb Amputees: Assessment of Discrete Vibrotactile Stimuli Perception During Walking

Biosystems & Biorobotics - Wearable Robotics: Challenges and Trends ◽

10.1007/978-3-030-01887-0_21 ◽

2018 ◽

pp. 105-109 ◽

Cited By ~ 2

Author(s):

Mariangela Filosa ◽

Ilaria Cesini ◽

Elena Martini ◽

Giacomo Spigler ◽

Nicola Vitiello ◽

...

Keyword(s):

Lower Limb ◽

Sensory Feedback ◽

Feedback System ◽

Lower Limb Amputees

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Effects of tDCS Dosage on Working Memory in Healthy Participants

10.1101/192419 ◽

2017 ◽

Cited By ~ 1

Author(s):

Stevan Nikolin ◽

Donel Martin ◽

Colleen K. Loo ◽

Tjeerd W. Boonstra

Keyword(s):

Working Memory ◽

Response Time ◽

Effect Size ◽

Biological Effects ◽

Parallel Group Design ◽

Parallel Group ◽

P3 Amplitude ◽

Time Accuracy ◽

Study Designs ◽

Healthy Participants

AbstractBackgroundTranscranial direct current stimulation (tDCS) has been found to improve working memory (WM) performance in healthy participants following a single session. However, results are mixed and the overall effect size is small. Interpretation of these results is confounded by heterogeneous study designs, including differences in tDCS dose (current intensity) and sham conditions used.AimsWe systematically investigated the effect of tDCS dose on working memory using behavioural and neurophysiological outcomes.MethodsIn a single-blind parallel group design, 100 participants were randomised across five groups to receive 15 minutes of bifrontal tDCS at different current intensities (2mA, 1mA, and three sham tDCS conditions at 0.034mA, 0.016mA, or 0mA). EEG activity was acquired while participants performed a WM task prior to, during, and following tDCS. Response time, accuracy and an event-related EEG component (P3) were evaluated.ResultsWe found no significant differences in response time or performance accuracy between current intensities. The P3 amplitude was significantly lower in the 0mA condition compared to the 0.034mA, 1mA and 2mA tDCS conditions. Changes in WM accuracy were moderately correlated with changes in the P3 amplitude following tDCS compared to baseline levels (r = 0.34).ConclusionsWorking memory was not significantly altered by tDCS, regardless of dose. The P3 amplitude showed that stimulation at 1mA, 2mA and a sham condition (0.034mA) had biological effects, with the largest effect size for 1mA stimulation. These findings indicate higher sensitivity of neurophysiological outcomes to tDCS and suggests that sham stimulation previously considered inactive may alter neuronal function.

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