Effect of Calibration Method on Tekscan Sensor Accuracy

Abstract

Tekscan pressure sensors are used in biomechanics research to measure joint contact loads. While the overall accuracy of these sensors has been reported previously, the effects of different calibration algorithms on sensor accuracy have not been compared. The objectives of this validation study were to determine the most appropriate calibration method supplied in the Tekscan program software and to compare its accuracy to the accuracy obtained with two user-defined calibration protocols. We evaluated the calibration accuracies for test loads within the low range, high range, and full range of the sensor. Our experimental setup used materials representing those found in standard prosthetic joints, i.e., metal against plastic. The Tekscan power calibration was the most accurate of the algorithms provided with the system software, with an overall rms error of 2.7% of the tested sensor range, whereas the linear calibrations resulted in an overall rms error of up to 24% of the tested range. The user-defined ten-point cubic calibration was almost five times more accurate, on average, than the power calibration over the full range, with an overall rms error of 0.6% of the tested range. The user-defined three-point quadratic calibration was almost twice as accurate as the Tekscan power calibration, but was sensitive to the calibration loads used. We recommend that investigators design their own calibration curves not only to improve accuracy but also to understand the range(s) of highest error and to choose the optimal points within the expected sensing range for calibration. Since output and sensor nonlinearity depend on the experimental protocol (sensor type, interface shape and materials, sensor range in use, loading method, etc.), sensor behavior should be investigated for each different application.

How Do Hindfoot Fusions Affect Ankle Biomechanics: A Cadaver Model

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Effect of partial meniscectomy at the medial posterior horn on tibiofemoral contact mechanics and meniscal hoop strains in human knees

“…Each sensor was calibrated under the same environmental conditions as those registered during the in vitro experiments. This calibration is more precise 20 than the manufacturer's process, particularly when used at a locally limited area under full saturation pressure. 21 The anterior and posterior aspects of the menisci (alH ¼ anterolateral horn; plH ¼ posterolateral horn; amH ¼ anteromedial horn; pmH ¼ posteromedial horn; Fig.…”

Evaluation of the Tekscan F-SCAN system for measurement of the kicking force in horses

“…Furthermore, the accuracy of the Tekscan System may be lower than reported in dynamic loading situations because of the effects of shear loads, loading between curved surfaces or small contact areas. Sensor output and output variability depend on the stiffness of the contact materials (Brimacombe et al, 2009). Lou et al (1998) found the sensor to be sensitive to surface conditions, loading speeds and temperature, and rated the F-Scan Tekscan sensor system unsuitable for hard surface contact.…”

“…The measuring system was con nected via a 10-m cable and a 16-bit receiver card to a microcomputer with the corresponding pressure and force measurement software program. To obtain meaningful measurements, the Tekscan sensors must be calibrated to the anticipated pressure range (Brimacombe et al, 2009). Therefore, before obtaining any force measurements, each sensor was individually calibrated with the previously recorded weight borne by the hind limbs with the horse standing square.…”