Scalability of haptic systems with non-passive virtual environments.

다국어 초록 (Multilingual Abstract)

Haptic systems comprising of a human operator, haptic device (robot) and discrete-time virtual environment are examined to guarantee stable interaction when the virtual environment experiences energy growth. The energy growth or non-passive behavior is attributed to characteristics often found in practical implementation; such as nonlinearities, discretization and real-time constraints. Therefore, it is important to model this behavior to derive an accurate stability result that guides system design.
This document relies on the storage function form of nonlinear passivity theory to characterize each of the components of the haptic system in terms of energy. Coupled stability theory is then used to examine the energy transfer between the components. An important result is identified in which energy growth in the virtual environment is allowed as long as the haptic device provides sufficient dissipation (damping).
The latter part of this document presents the three case studies of nonlinear mass-spring-damper environments, impulse-based rigid body simulation and remote haptic interaction. The insight gained by applying the theory helps guide system design that guarantees stable interaction. The key is the ability to bound the energy growth in the virtual environment, and then determine how much energy the haptic device can dissipate.
In general, the concepts developed in this document can be applied to human/machine interface applications. In particular, the field of bilateral teleoperation can benefit from the emphasis placed on force feedback. This work has also paved the way for future applications concerned with the stability of network-based haptic interaction.