A Design of Wearable Goniometers for Measuring Carpal Angular Movement

摘要

This study designs a wearable wrist Goniometer (WWG) composed of an Arduino Nano and 2 GY-521 accelerometer-gyroscopes to avoid the above shortcomings.The reliability of WWG was tested by performing two experiments in sequence. Firstly, the component tested experiment is to check the accuracy of the GY-521 accelerometer- gyroscopes embedded in The MPU-6050, by measuring the real moved angles (RMAs) and their measured angles (MAs) form GY-521. The results showed that the differences between RMAs and Mas were ranged from -2.4331° to 2.3382°, which are larger than component sensitivity 131 LSB/°/sec (about 1.9°) the manufacturer claimed. Therefore, this study performed the regression analysis to find the regression equation of RMA and MA. Therefore, a predicted RMA (pRMA) could be predicted by the regression equation.Next, the WWG tested experiment is to test the measurement accuracy of the WWG when it is worn on a human body. The WWG worn on the subject's forearm measured his maximum carpal movement angles in six directions (pronation, supination, palmar flexion, dorsiflexion, ulnar deviation, and radial deviation). The measured values are the WWG measured angles (wMAs). These angles were transformed into pRMAs by the regression equation. At the same time, three pictures were taken from x, y, and z directions respectively to record the carpal postures in the six directions. Next, the pictures were uploaded to the Auto CAD, drawing software, to measure the actual movement angles (aMAs). The result showed that the differences between the pRMAs and aMAs in the six directions were ranged from -1.372° to 1.566°, the component sensitivity the gyroscope's factory claimed. Based on the above results, using the WWG can measure the angles in which sensitivities is not less than 1.566°.