Mechanical design optimization for multi-finger haptic devices applied to virtual grasping manipulation

This paper describes the design of a modular multi-finger haptic device for virtual object manipulation. Mechanical structures are based on one module per finger and can be scaled up to three fingers. Mechanical configurations for two and three fingers are based on the use of one and two redundant axes, respectively. As demonstrated, redundant axes significantly increase workspace and prevent link collisions, which is their main asset with respect to other multi-finger haptic devices. The location of redundant axes and link dimensions have been optimized in order to guarantee a proper workspace, manipulability, force capability, and inertia for the device. The mechanical haptic device design and a thimble adaptable to different finger sizes have also been developed for virtual object manipulation

Development and evaluation of a device for the haptic rendering of rotatory car doors

Virtual prototyping of car doors enhanced with haptic feedback is a promising way to decrease the number of physical prototypes. We clarify, correct, summarize, and extend our previous work on the haptic simulation of car doors. A fundamental issue is the derivation of the performance specification of a task-optimized haptic interface, which is based on the knowledge of the typical user interaction with a car door and a comprehensive model of the dynamics of a rotatory car door. We reason that a direct drive with a high torque output (≥ 100 N·m) and a high control bandwidth has to be used. Consequently, we created a backlash-free very stiff device providing a safe and high-fidelity haptic rendering. Finally, we conducted an extensive user study with 17 participants. An important result is that the haptic simulation can be reliably used to evaluate different door concepts if the difference between them is larger than 5 N·m. Furthermore, the participants did not like a high effort for closing the door, while both a low and a medium effort are appreciated. This is in accordance with the heuristic findings of the automotive industry, which shows the effectiveness of our virtual prototyping approach. © 2009 IEEE