A Hierarchical Approach for Design and Assembly of Mechanisms

We introduce a hierarchical approach for the analysis and design of systems with multiple frictional contacts, with a focus on applications to the design of part feeding and assembly processes. The simplest model in the hierarchy is the geometric model described by a set of non-penetration constraints that depends only on the geometry of the design. The model with the highest fidelity is one that incorporates rigid body dynamics, joint constraints, and frictional contacts. Our approach is based on a scheme that first uses Rapidly-exploring Random Trees (RRTs) to explore and prune the feasible set of design parameters. The next step is to redesign the system iteratively with the pruned parameter set using a model with higher fidelity. This process is repeated with improved models, until an optimal design is obtained with the model of desired fidelity. We illustrate the models, the design process, and the feasibility of this hierarchical approach by applying it to the design of a simple part feeder. ∗Address all correspondence to this author. †The General Robotics, Automation, Sensing and Perception Laboratory