Guaranteed stability of haptic systems with nonlinear virtual environments

Design of haptic systems that guarantee stable interaction is a challenging task. Virtual environments are typically highly nonlinear-resulting in a n onpassive discrete-time model. This paper will investigate how nonlinear ma ss/spring/damper virtual environments can be designed to guarantee the abse nce of oscillations and other chaotic behavior in the signal presented to t he human operator,In particular, delayed and nondelayed implementation of t he mass/spring/damper virtual environment is considered, revealing a. nonin tuitive result with regard to the allowable local stiffness.