Modeling the human hand as it interacts with a telemanipulation system

This paper describes the development of a linear lumped-parameter hand/arm model for the operator of a telemanipulation system. The authors previously developed a control architecture that implements frequency-domain loop-shaping compensators to improve the transparency or “feel” of a telemanipulation system, and a human model is used when simulating this architecture. Typically, the human is modeled as a second order mass-spring-damper system. The five-parameter model presented in this paper, however, includes an additional spring and damper to better approximate the dynamics within the specific frequency range for which compensators will be designed, typically below 20-30 Hz. The model form and parameters were determined from experimental data taken from a telemanipulation system with a single translational degree-of-freedom. Additional data was taken from a system with three actuated degrees-of-freedom, and a set of model parameters was determined for each direction of motion. Each set of model parameters presented in this paper is for the specific grip type and hand/arm orientation used during interaction with each particular telemanipulation system, however similar sets of parameters using this human model could be obtained for interaction with other telemanipulation systems and haptic interfaces. A comparison of the five-parameter model with a two-parameter spring-damper model suggests that in some cases the use of additional model parameters may not offer a significant improvement.