Experiments, Modeling, and Automatic Planning for Fixturing and Gripping

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Abstract IIS-9901056Burdick, JoelCalifornia Institute of Technology$92,265 - 12 mos.Experiments, Modeling, and Automatic Planning for Fixturing and GrippingThis is the first year funding of a three-year continuing award. The research is to investigate analytically and experimentally into problems of workpiece fixturing and related problems of object gripping. Prior efforts in automated fixture planning have largely been based on rigid-body models or ad-hoc models of compliant contact. These models are too inaccurate for manufacturing operations that involve large forces and precision deflection tolerances. The first goal of this research is to extend work on compliant contact modelling to include other important contact phenomena, such as the effect of friction in nonlinearly compliant contacts, and global deformations in workpieces with slender internal structures. Further, the PI plans to integrate therelevant contact phenomena into a single effectively computable model. A second major goal is to construct a comprehensive experimental system that will be the first to measure the complete range of physical phenomena underlying the fixturing problem. These experiments should not only validate and refine the models, but also help convince the community of fixturing researchers and practitioners that nonlinear compliance models are to be preferred over currently used ad-hoc models. A third goal is to develop automated fixturing and gripping synthesis procedures that are based on the extended models. These algorithms will be able to automatically generate fixture arrangements that guarantee meaningful performance criteria, such as deflection tolerance, in the presence of externally applied loads. The PI also wishes to include design parameters, such as surface curvature and the minimal number of fixtures needed to guarantee taskperformance criteria, that have not previously been addressed in the fixture synthesis literature. In the long term, the PI's team plan to use these results to study active control of the fixture loading process so as to inherently ensure accurate part localization. Since fixturing is closely related to gripping, these results should have a longer-term impact on the deployment of more sophisticated gripping devices.