A simple method for slip detection of prosthetic hand

To achieve a human like grasping with a multifingered robot hand, the grasping force should be controlled without using information from the grasped object such as its weight and friction coefficient. In this study, we describe an experiment focusing on the consistency of slip detection of a prosthetic hand equipped with a force sensing resistor (FSR) which can capture force variations during the slip of grasped object. A method for detecting the slip of a grasped object using the discrete wavelet transform (DWT) of the high frequency signal output of FSR was proposed. The effectiveness of the proposed method was confirmed in tests of slip detection during grasping. Moreover, the test results indicated that the hardness and mass of the object and disturbing force have very limited impact on the slipping patterns. Finally, a simple model was proposed to obtain the decline value of grasping force by using the results from DWT. This model can also be used as a method for slip detection.