Institute for Systems Research Technical Reports
Permanent URI for this collectionhttp://hdl.handle.net/1903/4376
This archive contains a collection of reports generated by the faculty and students of the Institute for Systems Research (ISR), a permanent, interdisciplinary research unit in the A. James Clark School of Engineering at the University of Maryland. ISR-based projects are conducted through partnerships with industry and government, bringing together faculty and students from multiple academic departments and colleges across the university.
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Item An Investigation of the Mechanics in the Machining of Ceramic Material(1994) Satish, K.G.; Zhang, G.M.; ISRThis study is an investigation into the mechanics in machining ceramic materials. Extensive experimentation is done in an effort to understand the process of material removal. The theory of fracture mechanics is used to explain experimental findings. A five stage model of the machining of ceramics is proposed, and based on this understanding, guidelines are provided to adapt the traditional methods to machine ceramics. The possibility of developing a new submerged machining process is studied. The significant new findings in this research are: Cutting force has little change with increase in the cutting speed as a result of the combined effects of increase in loading rate and increase in temperature on the fracture toughness.The quality of the surface formed is better controlled by the variation in the chip size than by the mean of the chip size. Submerged machining create a unique environment which keeps the chip size variation under control.
Variation of the chip size increases with increase in the depth of cut, consequently degrading the finish quality. Similar effect of feed has also been observed, however, feed is not as significant as depth of cut.
The apparent coefficient of friction controls the tensile stress distribution in the vicinity of the cutting zone. A large friction force induces a tensile stress field confined to a narrow region, parallel to the machined surface, promoting chip formation.
Item A Systems Engineering Approach to the Development of an Information System for Creating ISO 9000 Quality Documentation(1994) Zhong, H.; Zhang, G. M.; ISRISO 9000 is a series of international quality standards developed by the International Organization for Standardization (ISO) in 1987. It provides a comprehensive set of generic standards that applies to all phases of the product development cycle, including design, manufacturing, and service. Since its establishment, ISO 9000 has gained widespread acceptance by companies as an integral part in achieving total quality management. More and more companies are registering to ISO 9000 to show their commitment to quality.One of the key components in the ISO 9000 certification process is the quality manual, which deals with the company's business procedures ranging from design to service. With rapid advancement of computer technologies, the task of producing such a quality manual can be done more efficiently with the help of a well-designed information system. This thesis presents the design and implementation of such an information system where systems engineering principles are incorporated. A survey of relevant information including quality, ISO 9000, information system, database, human factors, user interface, and tradeoff analysis is also presented.
Three unique features of the developed information system are: System architecture, which follows the basic framework of the ISO 9000 standards in terms of data storage, user interface and report generation.
Microsoft Windows and Visual Basic development platform, which makes the prototype ideally suited for small companies such as Compression, Telecommunications Corporation (CTEL), an industry sponsor.
Relational database approach, which offers flexibility and makes the prototype adaptable to the needs of small companies.
The information system prototype developed in this thesis work has been used to produce a quality manual for Compression Telecommunications Corporation (CTEL), and will be used in the ISO 9000 registration process.
Item The Design of Tendon-Driven Manipulators with Isotropic Transmission Characteristics(1994) Ou, Y-J.; Tsai, L-W.; ISRThis dissertation deals with the synthesis of the mechanical power transmission structure in tendon-driven manipulators. The force transmission characteristics from the end-effector space to the actuator space has been investigated. It is shown that tendon forces required to generate an output force at the end- effector are functions of the transmission structure matrix and the manipulator Jacobian matrix. The sufficient and necessary conditions for a transmission structure to be admissible are summarized and an efficient algorithm to check admissible structures is derived.Based on the analysis of static force transmission, a general theory is developed for the synthesis of tendon-driven manipulators with isotropic transmission characteristics. It is shown that an n-dof (degree of freedom) manipulator can possess these characteristics if it is made up of n + 1 of 2n tendons and if its link lengths and pulley sizes are designed according to two equations of constraint. Design equations for synthesizing a manipulator to posses isotropic transmission characteristics are derived.
To demonstrate the theory, two examples are used: (1) a two-dof planar manipulator and (2) a three-dof spatial manipulator. The tendon forces in each manipulator with different transmission structures are compared. It is shown that manipulators with an isotropic transmission structure have more uniform forces distribution among their tendons.
To further understand the isotropic transmission characteristics, the properties of a manipulator with an isotropic transmission structure are then discussed from many different perspectives. The discussion includes the tension control algorithm, maximum tensions, kinematic performance, antagonistic forces among tendons, and survivability of a transmission structure with 2n tendons.
Finally, a new design methodology is developed to determine tendon routings and pulley sizes of a special three-dof tendon-driven manipulator. This design methodology ensures that each tendon will subject equal maximum tension when an external force is applied to the end- effector in all possible directions. The design is further enhanced when the criteria of isotropic transmission are imposed. A design example is presented to demonstrate the features and to compare with the Salisbury finger.
Item A Taste of the Future: The Summer Engineering Program(1994) Zhang, G.; Berman, M.; Fines, J.; ISRThe problem of increasing engineering enrollment of female students to meet the national need has been of great concern to engineering educators. This paper presents the experience gained from the 1993 summer engineering program. Thirty female high school students in grade 11 participated. The program teaches engineering design through a product realization process and introduced engineering disciplines through laboratory work and field trips. With a stimulating first experience in engineering, the participating students built up their confidence. Evaluation results show that the program has been extremely successful in encouraging female students to consider choosing the path to an engineering career.Item Design of Material Flow Networks in Manufacturing Facilities(1994) Herrmann, Jeffrey W.; Ioannou, George; Minis, Ioannis; Nagi, R.; Proth, J.M.; ISRIn this paper we consider the design of material handling flow paths in a discrete parts manufacturing facility. A fixed-charge capacitated network design model is presented and two efficient heuristics are proposed to determine near-optimal solutions to the resulting NP- hard problem. The heuristics are tested against an implicit enumeration scheme used to obtain optimal solutions for small examples. For more realistic cases, the solutions of the heuristics are compared to lower bounds obtained by either the linear programming relaxation of the mixed integer program, or an iterative dual ascent algorithm. The results obtained indicate that the heuristics provide good solutions in reasonable time on the average. The proposed methodology is applied to design the flow paths of an existing manufacturing facility. The role of the flow path network problem in the integrated shop design is also discussed.Item Hierarchical Production Planning for Complex Manufacturing(1994) Mehra, Anshu; Minis, Ioannis; Proth, J.M.; ISRA hierarchical approach to production planning for complex manufacturing systems is presented. A single facility comprising of a number of work-centers that produce multiple part types is considered. The planning horizon includes a sequence of time periods, and the demand for all part types is assumed to be known. The production planning problem consists of minimizing the holding costs for all part types as well as the work-in- process, and the backlogging cost for the end items. We present a two- level hierarchy that is based on aggregating parts to part families, work-centers to manufacturing cells and time periods to aggregate time periods. The solution at the aggregate level is imposed as a constraint to the detailed level problem which employs a decomposition based on manufacturing cells. This architecture uses a rolling horizon strategy to perform the production management function. We have employed perturbation analysis techniques to adjust certain parameters of the optimization problems at the detailed level to reach a near- optimal detailed production plan.Item Hierarchical Production Planning with Part, Spatial and Time Aggregation(1994) Herrmann, Jeffrey W.; Mehra, Anshu; Minis, Ioannis; Proth, J.M.; ISRA hierarchical approach to planning production in complex manufacturing systems is presented. A single facility containing a number of work-centers that produce multiple part types is considered. The planning horizon includes a sequence of time periods, and the demand for all part types is assumed to be known. The production planning problem consists of minimizing the holding costs for the work-in-process and finished goods inventory and the backlogging costs for unfulfilled demand. We present a two-level hierarchy that is based on aggregating part types to part families, work-centers to manufacturing cells and time periods to aggregate time periods. The solution of the aggregate optimization problem is imposed as a target in the optimization problems at the detailed level. This architecture uses a rolling horizon strategy to manage production.Item A Dual Ascent Approach to the Fixed-Charge Capacitated Network Design Problem(1994) Herrmann, Jeffrey W.; Ioannou, George; Minis, Ioannis; Proth, J.M.; ISRIn this paper we consider the problem of constructing a network over which a number of commodities are to be transported. Fixed costs are associated to the construction of network arcs and variable costs are associated to routing of commodities. In addition, one capacity constraint is related to each arc. The problem is to determine a network design that minimizes the total cost; i.e. it balances the construction and operating costs. A dual ascent procedure for finding improved lower bounds and near- optimal solutions for the fixed-charge capacitated network design problem is proposed. The method is shown to generate tighter lower bounds than the linear programming relaxation of the problem.Item On-line Assessment of Surface Roughness through Fractal Geometry(1994) Gopalakrishnan, Shivakumar; Zhang, Guangming; ISROn-line measurement of surface roughness is an important element in a Computer Integrated Manufacturing (CIM) environment. Current methods of contact measurement are not suitable as they interfere with the machining process. Optical methods, such as laser profilometry, in general, use expensive and large equipment, which pose difficulties in the implementation on the machine tool for on-line monitoring. This paper presents an optical area based surface characterization technique which applies fractal geometry and basic light scattering principles. The novelty in this approach is that the above principles are used to facilitate in- process measurement and control. A prototype of this system is developed and the experimental results are presented. The capabilities and future potential of this system are demonstrated.Item The Mechanics of Material Removal Mechanisms in the Machining of Ceramics(1994) Zhang, G.M.; Satish, K.G.; Ko, Wing F.; ISRThis paper presents a study on the mechanics of material removal for ceramic materials by observing single-point turning process of aluminum oxide (Al2O3). On-line cutting force measurement is performed and the surface integrity is characterized off-line by examining the surface texture. A theoretical analysis of fracture mechanics provides a comprehensive understanding of the chip formation process, and a model describing the material removal mechanisms is discussed. Based on the model, a systematic investigation of the chip fragments formed during machining is performed.