UBC Theses and Dissertations
Simulation of contact textures and forces with application to haptic interfaces Siira, Juhani
This thesis will consider the simulation and display of contact forces as currently present in much of the robotics literature. In particular, the following two issues are addressed. Texture forces are not currently routinely included in haptic display algorithms, nor are there comprehensive frameworks for using physical parameters to generate realistic texture forces. Algorithms are required which combine implementation ease with minimal computation requirements. This thesis will present one such algorithm, which has been shown to produce realistic feeling texture forces by generating force pulses at high bandwidth. The algorithm has the potential to use physical measures of surface roughness to produce accurate texture forces. Much of the contact simulation currently presented uses the spring/damper as a surface model. Although the spring/damper can be an accurate model for impact, it is not generally nearly as applicable to low-speed or quasi-static load cycling, and it requires careful consideration when applied to multi-point contact situations (when naive application can cause incorrect results). The shortcomings of the spring/damper system are exposed, and an alternative model is presented which corrects the deficiencies of the spring/damper, without greatly increasing implementation complexity. Some of the features of the new model include energy dissipation during quasi-static cycling, correct multi-point contact behaviour without modification, and a clearly established equilibrium transition time, which can be beneficial in maintaining subsets of active objects in a complicated simulation.
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