This thesis presents the development of a model for analyzing the design of an automated live-bird transfer system (LBTS) developed at Georgia Tech. One of the most fundamental tasks in the automated transferring is to design and control a grasping system that is capable of accommodating a specified range of objects without causing damage. However, unlike grasping in robotic research that focuses on dexterous manipulation of a single object, repetitive transfer of live objects in a production line requires continuous grasping at high-speed. This thesis research investigates the use of rotating fingers (capable of undergoing large deflections) to cradle live birds on a moving conveyor for subsequent handling. As compared to fingers with multiple active joints, flexible fingers have many merits, for they are lightweight and have no relative individually moving parts. Their ability to accommodate a limited range of varying sizes, shapes, and the natural reactions of some objects makes rubber fingers an attractive candidate for use as graspers in a high-speed production setting. However, the advantages of flexible fingers are seldom exploited for grasping because of the complex analysis involved in the design. In order to reduce the number of birds and hardware/software design configurations to be tested, a good understanding of the object dynamics throughout the grasping process is necessary. In this thesis, a quasi-static model has been developed for predicting the contact force between a moving object and a rotating finger. The model has been validated with the experimentally measured data and the computed results using finite element (FE) methods. Finally, an illustrative application of the validated model has been demonstrated in the design of a rotating hand used in the automated LBTS. As illustrated in the simulation results, the computed contact forces can be used as a basis for predicting potential bruises on the bird that may be caused by the rotating fingers. The analytical model presented in this paper provides a rational basis for optimizing the design of the grasping system and developing a controller for a high-speed transfer system. It is expected that the analysis presented here can be readily extended to other dynamic systems involving the use of flexible beams.

The finite element method (FEM) has difficulty solving certain problems where adaptive mesh is needed. Motivated by two engineering problems in live-object handling project, this research focus on a new computational method called the meshless method (MLM). This method is built upon the same theoretical framework as FEM but needs no mesh. Consequently, the computation becomes more stable and the adaptive computational scheme becomes easier to develop. In this research, we investigate practical issues related to the MLM and develop an adaptive algorithm to automatically insert additional nodes and improve computational accuracy. The study has been in the context of the two engineering problems: magnetic field computation and large deformation contact. First, we investigate the effect of two discretization methods (strong-form and weak-form) in MLM for solving linear magnetic field problems. Special techniques for handling the discontinuity boundary condition at material interfaces are proposed in both discretization methods to improve the computational accuracy. Next, we develop an adaptive computational scheme in MLM that is comprised of an error estimation algorithm, a nodal insertion scheme and a numerical integration scheme. As a more general approach, this method can automatically locate the large error region around the material interface and insert nodes accordingly to reduce the error. We further extend the adaptive method to solve nonlinear large deformation contact problems. With the ability to adaptively insert nodes during the computation, the developed method is capable of using fewer nodes for initial computation and thus, effectively improves the computational efficiency. Engineering applications of the developed methods have been demonstrated by two practical engineering problems. In the first problem, the MLM has been utilized to simulate the dynamic response of a non-contact mechanical-magnetic actuator for optimizing the design of the actuator. In the second problem, the contact between the flexible finger and the live poultry product has been analyzed by using MLM. These applications show the developed method can be applied to a broad spectrum of engineering applications where an adaptive mesh is needed.