Analysis and Performance Evaluation of a 3-DOF Wearable Fingertip Device for Haptic Applications

Wearable fingertip device is a promising form to display haptic stimuli since it provides a lightweight and natural way for operators to grasp or manipulate the objects in the virtual environment. This paper focuses on the analysis and performance evaluation of a wearable fingertip device for haptic applications. The device is equipped with three small servo motors and can provide 3-DOF (degree of freedom) force feedback at fingertip with contact/non-contact capability. It combines a five-bar linkage and a slider-crank linkage, and these two linkages are decoupled, leading to simpler kinematics than some devices with coupled structures. In order to present the device, its mechanical analysis, kinematics analysis, and static force analysis were carried out at first. Then, four experiments were designed and conducted to evaluate the device performance quantitatively. The first experiment aimed to verify the effectiveness in rendering variable stiffness. The second experiment investigated its capability in providing different skin stretch directions for operators. The third experiment evaluated its performance improvement during virtual manipulation. The last experiment aimed to verify the effectiveness in displaying mass information during remote manipulation. The experimental results indicated that this device was capable of rendering various stiffness. It could generate eight clear skin stretch directions. The subjects had better performance during virtual manipulation with cutaneous feedback provided by the device than without cutaneous feedback. The device was also capable of displaying mass information during remote manipulation.