Simulation of product's grasping

1. Abstract In the process of designing hand-held devices customer evaluation is very important. This is usually done by using a physical model of the product and customers with different hand-size and strength. In this paper a new approach is presented, when the user is interacting with virtual models, but without restricting the hand motion with wires and devices for force feedback or tracking. The user – product interaction scenario is the following: the 3D model is presented to the user on a volumetric 3D display (holographic display) and user is grasping this virtual model. The hand motion and positions of the fingers are measurement with a passive optical tracking system. For this a camera system with infrared light and reflective markers are used. These markers are attached to specific landmarks of the user’s hand and relative position of them is providing the input data in a parametric hand model developed in Matlab and Simulink software. This virtual hand model is following the motion of the real hand (using kinematic constraints). The force-feedback from the virtual hand and the product interaction is obtained from collision but the software is limiting this interaction force according to the user’s gender and hand size. Because no real force feed-back is provided the user can decide upon the correctness of the grasping posture only from visual feedback and for this reason color markers are provided on the virtual product. From the simulation model important information regarding the ergonomics of the product and user’s behaviors can be obtained. At the end of the paper a case study is presented. 2.