Design and validation of a complete haptic system for manipulative tasks

The present work deals with the design, implementation and assessment of a new haptic system specifically conceived for manipulative tasks in virtual environments. Such a system has been designed by taking into account specific issues related to fine manipulation, such as multipoint haptics, coherence, transparency, and physical representation. The haptic system herein described includes also a high performance virtual-environment engine who can manage a wide set of information and provide then to the user. This engine includes numerical algorithms for representing complex phenomenas such as: mass properties, objects weights and gravity acceleration, inter-objects collision and multifinger manipulation. The present paper also reports a preliminary experimental validation of the achieved system. The validation procedure has been designed on the basis of the assessment procedures followed for manipulative tasks of real objects, that can be found in the scientific medical literature. According to the experiments performed, the most relevant relationships found in physical manipulation have also been confirmed in virtual manipulation. However, an in depth analysis of the results shows that several simulation parameters may also affect the features of force control during virtual manipulation. keywords: haptic interface, virtual grasping, multipoint interaction