Kinematics and workspace-based dimensional optimization of a novel haptic device for assisted navigation

This article presents the development of a multi-point force feedback device, composed of five mechanisms that each provide a two degree-of-freedom (DOF) haptic feedback for every finger for a total of 10 DOF. This work investigates the theoretical workspace of a human index finger and uses a two DOF 7-bar linkage mechanism that is synthesized based on such a workspace. This research determines the closed-form solutions to the forward and inverse position, and presents a prototype that is built and tested as a proof of concept of the novel device. The workspace of the constructed mechanism is compared with theoretical models in order to assess their similarity and the feasibility of accelerometers as position-sensing instruments is also tested. Two sets of experiments test the performance of the mechanism and its reliability as a human-machine interface. Firstly, an operator successfully navigates an unmanned aerial vehicle avoiding an obstacle as force replaces audiovisual feedback. In the second experiment, the operator searches a chemical source using an unmanned ground vehicle, where chemical gradient is transmitted to the user as force signals.