Ibrahim Zeid

Graspar: a flexible, easily controllable robotic hand

With only one motor per finger and a simple, easy to maintain, mechanical structure, the Graspar robotic hand uses minimal computation to provide secure grasping of objects ranging from eggs and light bulbs to tennis rackets, coffee pots and stuffed toys. We first discuss currently developed hands, and show the motivation for our work. Next, we present the mechanical structure of our robotic hand and the antagonistic tendoning system. We then show how this structure moves and complies to the object surface. We discuss how we chose the pulley diameters for our tendoning system by maximizing the workspace of the fingers while mechanically insuring that the hand cannot collide with itself. Our control algorithm which uses simple mechanical switches is presented.

A case-based reasoning approach to planning for disassembly

With recycling regulations, resource conservation needs and an increased awareness of the state of the environment by both the consumer and the producer, many companies are establishing disassembly plants and developing product designs that specifically facilitate disassembly. Once disassembled, the items can be reused, recycled or discarded. One can identify two distinct aspects of the disassembly problem: design for disassembly (DFD) and planning for disassembly (PFD). The goal of DFD is to design products that are easy to disassemble. On the other hand, the objective of PFD is to identify efficient sequences to disassemble products. This paper focuses on the PFD aspect of disassembly. Because there could be many ways to disassemble a given product, PFD knowledge is accumulated by experience. Such knowledge is valuable, and should be captured, saved and reused to solve similar problems that arise in the future. In this paper, we propose case-based reasoning (CBR) as an approach to solve PFD problems. CBR is based on the fundamental principle that problem solving can benefit from solutions to past problems that have been attempted. The technique and issues related to the application of CBR to PFD are presented.

Finite element analysis of steadily moving contact fields

By introducing a moving updated Lagrangian observer, this paper develops traveling finite elements with the capacity to handle the global response resulting from steadily moving contact fields. The generality of the results is such that large deformation kinematics and kinetics as well as the full compliment of inertial fields can be handled. To streamline the handling of nonlinear behavior, an elliptically constrained solution algorithm is also developed. Employing this algorithm, the results of several numerical benchmarking studies are presented which illustrate the capacity of the moving updated Lagrangian formulation as well as the potential effects of nonlinearity.

Towards the design and development of a knowledge-based universal modular jigs and fixtures system

Jigs and fixtures are one of the important aspects of manufacturing. Parts may have different sets of fixturing requirements and call for different design strategies. Although there are numerous possibilities for fixture designs, a few basic configurations are clearly identifiable. Computer aided design (CAD) has done a little in assisting designers to design jigs and fixtures, making decisions of the best design selection, and providing designers with suggestions. The goal of this paper is to develop and document the design parameters and specifications utilized in jigs and fixtures design using universal modular jigs and fixtures design system (UMJFS). This is the first step to develop a knowledge-based Jigs and Fixture design and selection system. This application has the advantages of making the fixture design information completely modular and transparent, providing better match to the working conditions, reducing lead-time, and generally providing a significant enhancement of fixture productivity and economy. UMJFS has different standard and modular elements. This makes jigs and fixtures elements interchangeable and reusable. Designing a UMJFS then becomes a task of selecting and assembling the proper elements together.

Finite element modeling of rolling contact

Abstract A new static/rolling contact element will be developed in this paper. The element is capable of obtaining the contact fields of rolling/moving type structure such as tires, train wheels, roller bearings, etc. wherein steadily moving mechanical surface fields are involved. The contact algorithm is general in the sense that it can be applied to both linear and nonlinear problems wherin the full complement of inertial fields may be of importance. It can also handle the slip and non-slip conditions which may exist in the contact zone. Based on the algorithm developed, the results of several numerical experiments will be presented.

Characteristics of an effective design plan system to support reuse in case-based mechanical design

Design plan systems play an important role in applying case-based reasoning (CBR) to mechanical design. They are responsible for the representation and evaluation of design plans. Design plans are stored as the actual cases in the case base of a CBR system. In this paper, we discuss design reuse and related open issues: plan modification and plan adaptation. It is shown that these issues need to utilize design knowledge associated with both design procedure and design rationale. An overview of current design systems is given. These design systems have not been able to address the issues associated with design reuse. This has, in effect, made them unsuitable for use in a robust CBR system for mechanical design. Based on this discussion, this paper presents the characteristics of an effective design plan system to support reuse in case-based mechanical design. It is concluded that a design plan system should be a mixture of both the design procedure model and the design rationale model. An implementation of such a design plan system is presented with an example.

DEJAVU: case-based reasoning for mechanical design

The architecture and implementation of a mechanical designers assistant shell called DEJAVU is presented. The architecture is based on an integration of design and CAD with some of the more well known concepts in case-based reasoning (CBR). DEJAVU provides a flexible and cognitively intuitive approach for acquiring and utilizing design knowledge. It is a domain independent mechanical design shell that can incrementally acquire design knowledge in the domain of the user. DEJAVU provides a design environment that can learn from the designer(s) until it can begin to perform design tasks autonomously or semi-autonomously. The main components of DEJAVU are a knowledge base of design plans, an evaluation module in the form of a design plan system, and a blackboard-based adaptation module. The existance of these components are derived from the utilization of a CBR architecture. DEJAVU is the first step in developing a robust designers assistant shell for mechanical design problems. One of the major contributions of DEJAVU is the development of a clean architecture for the utilization of case-based reasoning in a mechanical designers assistant shell. In addition, the components of the architecture have been developed, tailored or modified from a general CBR context into a more synergistic relationship with mechanical design.

Applying analogical problem solving to mechanical design

Abstract Design automation holds great benefits for mechanical-product development. In addition to saving engineers from having to carry out redundant tasks, mechanical design automation can also provide embodiment of knowledge, reduced dowstream manufacturing costs, reduced manual errors and more reliable designs. Most of the approaches to mechanical design automation, thus far, have required a large amount of domain-specific knowledge (e.g. expert systems), and/or have had to presume a particular style of design problem solving (e.g. top-down decomposition, bottom-up constructive). The paper proposes analogical problem solving as an approach for alleviating some of these inherit problems in mechanical design automation. Analogical problem solving is based on the fundamental principle that problem solving can be assisted by the review of solutions to past problems that have been attempted. The technique and issues related to the application of analogical problem solving to mechanical design are presented.

Distributed and intelligent information access in manufacturing enterprises through mobile devices

Due to the distributed nature of today’s enterprises and the growing number of employees who are mobile, newer models of communication are required to cater to the information needs of manufacturing personnel. Mobile applications such as information alerts, disconnected information processing and background processing are applications gaining significant attention in manufacturing companies. In this paper, we describe the framework and architecture of a mobile-agent-based system, which provides mobile information services to the workforce in motion in manufacturing enterprises. We emphasize on background and disconnected processing and demonstrate the use of a Mobile-agent-based system to achieve it. Recognizing the need to exchange information between various distributed information sources, we explore the use of XML-based agent communication and discuss how XML can be used for inter-agent communication. We describe the design and implementation of a prototype system and discuss application scenarios.

A knowledge base for indexing and retrieving disassembly plans

Disassembly has become an important issue recently, as people begin to be concerned about the environment and natural resources. Many methodologies have been used to tackle disassembly problems. Design for disassembly (DFD) and planning for disassembly (PFD) are the two main approaches to address such problems. The focus of this paper is on PFD. To assist planners to solve PFD problems, a system must have some heuristics and domain specific knowledge, which is related to the representation of the disassembly knowledge. In previous work, the authors proposed to use EMOPs (eposodic memory organization packet) for the knowledge representation of the PFD plan. This paper presents the implementation of the EMOP memory model. The model has been implemented in C++. Examples are presented to demonstrate the capabilities of the memory model.