The objective of this analytical and experimental research project is to develop new nonlinear modeling methods for the physics of contact in multi-body grasps and fixtures, and to verify these models on a novel experimental fixturing system. The analytical portion of the project will formulate lumped parameter nonlinear compliance laws that more accurately describe the physics of multi-body contact involving both friction and compliance. The experimental component of this project will create a novel experimental system that can accurately measure the forces involved in compliant and frictional fixturing arrangements. The analytical models will be verified and refined on this experimental fixturing system. The resulting nonlinear models will be used to develop novel fixturing and grasping algorithms that accept task specifications such as workload level and immobilization tolerance, and the adaptively select the simplest possible fixture arrangement that satisfies both the task constraints and the governing physics of the contacts.
Physical arrangements that involve contact between multiple bodies are common in industrial fixturing and robotic grasping applications. The success of fixture, grasp, and manipulation planning algorithms may crucially depend on the accuracy of the underlying contact models upon which the plans are based. If successful, the nonlinear contact models that will be developed in this research project will allow entirely new fixture planning paradigms. Current fixturing paradigms rely on conservative rigid body models to ensure proper workpiece immobilization. But many light-to-moderate duty applications need not be gripped by as many fixels as are required by these classical paradigms in order to achieve task specifications. The improved friction-compliance laws that will be created in this project will allow more intelligent and adaptive fixturing strategies that should yield simple yet robust fixturing and gripping systems. This research will also lead to new robotic manipulation algorithms that avoid catastrophic phenomena such as wedging and jamming.
