Evaluating the Effects of Load Area and Sensor Configuration on the Performance of Pressure Sensors at Simulated Body-Device Interfaces

Hamilton, Megan; Behdinan, Kamran; Andrysek, Jan

doi:10.1109/jsen.2020.2970964

Cited by 6 publications

(8 citation statements)

References 17 publications

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“…A CV of 10% or less was deemed to be acceptable for clinical use. 28 Other methods of assessing precision included evaluation of the standard error of the mean for applied pressures and the repeatability error for repeated measurements with the same input value. Inter-class Correlation Coefficients (ICC) were also used to investigate precision by assessing test-retest reliability (Table 1).…”

Section: Methodsmentioning

confidence: 99%

The accuracy and precision of interface pressure measuring devices: A systematic review

et al. 2021

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Introduction Interface pressure measuring devices are used to assess the pressures exerted by compression. Their performance, however, has not been considered as a contributing factor to reported inconsistences in the application of compression. A systematic review was undertaken to investigate the performance of commercially available devices used to measure interface pressure. Methods Six databases were searched identifying 17 devices, grouped into five sensor categories. Results A range of methodologies assessed the devices’ accuracy and precision, including method of pressure application, device calibration and type of surface used. No sensor category outperformed the others, however some individual sensors showed higher accuracy and/or precision compared to others. Two major factors influenced the performance of a number of sensors: the amount of applied pressure and the calibration method used. Conclusion Inconsistences in the application of compression may reflect, in part, issues related to accuracy and precision of the devices used to assess compression.

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Section: Methodsmentioning

confidence: 99%

The accuracy and precision of interface pressure measuring devices: A systematic review

et al. 2021

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“…An apparatus designed to simulate human tissue developed in a previous study evaluating pressure sensors under static conditions was used in this study. 15 A 2 cm layer of soft translucent silicone (Renew ® Silicone 10, Renew ® , Easton, PA, USA), shown to mimic behavior of human tissue, [20][21][22] was placed over the Instron base platen. An Instron 5944 Universal Testing System with a 100 N load cell (Instron, Norwood, MA, USA) applied loads up to 10 N. This force range was selected as it is within both sensor's working range and represents forces and pressures applied at the body-device interface in various biomedical applications.…”

Section: Testing Apparatusmentioning

confidence: 99%

“…12 – 14 However, such conditions are not representative of the dynamic conditions of a body-device interface, where the loading area fluctuates and typically is larger than the sensing area. Sensor performance has been shown to vary with the area of applied load, however, testing has not been performed under dynamic conditions, 15 despite well documented differences in sensor performance under static and dynamic conditions. 16 Previous research with piezo-resistive sensors has reported a trade-off between the dynamic performance (hysteresis error) and the static sensitivity, as increased stiffness will alter the viscoelastic behavior causing hysteresis and reduce static sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Dynamic Performance of Interfacial Pressure Sensors at a Simulated Body-Device Interface

Hamilton

Sivasambu

Behdinan

et al. 2021

Can. Prosthet. Orthot. J.

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BACKGROUND: Pressure sensing at the body-device interface can help assess the quality of fit and function of assistive devices during physical activities and movement such as walking and running. However, the dynamic performance of various pressure sensor configurations is not well established. OBJECTIVE(S): Two common commercially available thin-film pressure sensors were tested to determine the effects of clinically relevant setup configurations focusing on loading areas, interfacing elements (i.e. ‘puck’) and calibration methods. METHODOLOGY: Testing was performed using a customized universal testing machine to simulate dynamic, mobility relevant loads at the body-device interface. Sensor performance was evaluated by analyzing accuracy and hysteresis. FINDINGS: The results suggest that sensor calibration method has a significant effect on sensor performance although the difference is mitigated by using an elastomeric loading puck. Both sensors exhibited similar performance during dynamic testing that agree with accuracy and hysteresis values reported by manufacturers and in previous studies assessing mainly static and quasi-static conditions. CONCLUSION: These findings suggest that sensor performance under mobility relevant conditions may be adequately represented via static and quasi-testing testing. This is important since static testing is much easier to apply and reduces the burden on users to verify dynamic performance of sensors prior to clinical application. The authors also recommend using a load puck for dynamic testing conditions to achieve optimal performance. Layman's Abstract Pressure sensors can be used in prosthetics to provide clinicians with data about how well a device fits and functions. However, pressure sensors are unproven when it comes to use during activities such as walking or running. This study tested two common pressure sensors in a setup that applied forces similar to walking. These findings indicate that sensor calibration affects sensor accuracy. Accuracy can be improved by applying a small puck to the sensor to spread the load more evenly. With the puck, the performance of the sensors was found to be acceptable for potential use in clinical applications. These findings also show that dynamic testing of pressure sensors may not be needed prior to clinical usage. Instead, performance can be based on static testing which is easier to do. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/36059/27891 How To Cite: Hamilton M, Sivasambu H, Behdinan K, Andrysek J. Evaluating the dynamic performance of interfacial pressure sensors at a simulated body-device interface. Canadian Prosthetics & Orthotics Journal. 2021;Volume 4, Issue 1, No.4. https://doi.org/10.33137/cpoj.v4i1.36059 Corresponding Author: Jan Andrysek, PhD,Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, Toronto, Canada.Email: jandrysek@hollandbloorview.caORCID: https://orcid.org/0000-0002-4976-1228

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“…For instance, in body device applications, human subjects exert inconsistent actuation on the sensing area of the FSR sensor, leading to inconsistent repeatable measurements. Moreover, the variance in the repeatability measurements is due to the pressure distribution of the human fingers being larger than the sensing area [ 16 ]. Another limitation is that these systems only measure the axial pinch force exerted by the index–thumb fingers on the pincer object rather than the tangential force which represents the quantitative value of the gentle pull.…”

Section: Introductionmentioning

confidence: 99%

Quantification of the Therapist’s Gentle Pull for Pinch Strength Testing Based on FMA and MMT: An Experimental Study with Healthy Subjects

et al. 2021

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Static pinch strength against a therapist’s gentle pull is evaluated using the pincer grasp component of the Fugl Meyer Assessment (FMA) to assess pinch impairment after stroke. In the pincer grasp component, therapists applied a gentle pull to distinguish between a score of 1 (moderate pinch impairment) and a score of 2 (no pinch impairment). The gentle pull is described as a resistance equivalent to a manual muscle test (MMT) score 4/5. The accepted use of “gentle” as a qualitative description for the pull results is a non-standardized subjective interpretation. The goal of this paper was to determine the quantitative value of the gentle pull applied by the therapists as in their clinical practice using a pinch–pull gripping system. The FMA protocol was used to standardize the body and fingers positions of three occupational therapists who were then instructed to apply a gentle pull of 4/5 MMT using their thumb and index fingers (in a tip-to-tip pinch). The results show that the therapists exerted a mean gentle pull (4/5 MMT score) of 6.34 ± 0.98 N with high reliability and acceptable repeatability. In investigating the ability of healthy subjects to resist the gentle pull, 50 adult male volunteers were instructed to pinch the pincer object and resist a dynamic loading exerted by the pinch–pull gripping system as much as possible to the moment the pincer object slips away. The results show that all subjects were able to exert a pulling force higher than the quantitative value of the gentle pull.

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Evaluating the Effects of Load Area and Sensor Configuration on the Performance of Pressure Sensors at Simulated Body-Device Interfaces

Cited by 6 publications

References 17 publications

The accuracy and precision of interface pressure measuring devices: A systematic review

The accuracy and precision of interface pressure measuring devices: A systematic review

Evaluating the Dynamic Performance of Interfacial Pressure Sensors at a Simulated Body-Device Interface

Quantification of the Therapist’s Gentle Pull for Pinch Strength Testing Based on FMA and MMT: An Experimental Study with Healthy Subjects

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