Experiments and Modeling of Friction-Compliance Laws for Friction-Based Fixturing and Robotic Manipulation

这一分析和实验研究项目的目标是为多体抓取和夹具中的接触物理发展新的非线性建模方法，并在一种新的实验夹具系统上验证这些模型。该项目的分析部分将制定集总参数非线性顺应性定律，更准确地描述涉及摩擦和顺应性的多体接触的物理特性。该项目的实验组件将创建一种新的实验系统，该系统可以准确地测量柔顺和摩擦夹具布置中涉及的力。分析模型将在该实验夹具系统上进行验证和修正。所得到的非线性模型将被用于开发新的夹具和抓取算法，该算法接受诸如工作负荷水平和固定容差等任务规范，并自适应地选择满足任务约束和接触的支配物理的最简单的夹具布置。涉及多个物体之间接触的物理布置在工业夹具和机器人抓取应用中是常见的。夹具、抓取和操作计划算法的成功可能关键取决于计划所基于的基本接触模型的准确性。如果成功，将在本研究项目中开发的非线性接触模型将允许全新的夹具规划范例。目前的固定模式依赖于保守的刚体模型来确保适当的工件固定。但是许多轻到中等负载的应用程序不需要像这些经典范例为了实现任务规范所需要的那么多的Fixel。本项目中将创建的改进的摩擦-顺应定律将允许更智能和自适应的夹具策略，这些策略应该产生简单但坚固的夹具和夹持系统。这项研究还将导致新的机器人操纵算法，以避免发生楔入和堵塞等灾难性现象。

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.