Analysis of human movements in virtual environments: dealing with flexible objects

The paper presents a theoretical analysis of human reaching movements in manipulation of flexible objects. To predict the trajectory of human hand, a minimum crackle criterion has been recently proposed in literature. A different approach is explored in this paper. To explain the trajectory formation, we propose a dynamic version of the minimum hand jerk criterion. It is shown that this criterion matches experimental data available in literature. In addition, an analysis of this novel criterion shows the possibility of multiphase velocity profiles of the hand. Also, contrary to the minimum crackle criterion, our criterion produces bounded hand velocity profiles for multi-mass flexible objects. The results obtained in this paper can be used in devising new experimental protocols for the analysis of skillful human movements in virtual environments.