Browsing by Author "Gupta, Satyandra K."
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Item Algorithms for Computing Global Accessibility Cones(2002) Dhaliwal, Savinder; Gupta, Satyandra K.; Huang, Jun; Priyadarshi, Alok; ISRThis paper describes algorithms for computing global accessibility cones for various faces (i.e., the set of directions from which faces are accessible) in a polyhedral object. We describe exact mathematical conditions and the associated algorithm for determining the set of directions from which a planar face with triangular boundary is inaccessible due to another face in the object. By utilizing the algorithm to compute the exact inaccessibility region for a face, we present algorithms for computing global accessibility cones for various faces in the object. These global accessibility cones are represented in a matrix structure and can be used to support a wide variety of accessibility queries for the object. We provide several examples to show computational performance of our algorithm.Item An Application of Distributed Solid Modeling: Feature Recognition(1994) Regli, W.C.; Gupta, Satyandra K.; Nau, D.S.; ISRThe availability of low-cost computational power is a driving force behind the growing sophistication of CAD software. Tools designed to reduce time-consuming build-test-redesign iterations are essential for increasing engineering quality and productivity. However, automation of the design process poses many difficult computational problems. As more downstream engineering activities are being considered during the design phase, guaranteeing reasonable response times within design systems becomes problematic. Design is an interactive process and speed is a critical factor in systems that enable designers to explore and experiment with alternative ideas during the design phase. Achieving interactivity requires an increasingly sophisticated allocation of computational resources in order to perform realistic design analyses and generate feedback in real time.This paper presents our initial efforts to develop techniques to apply distributed algorithms to the problem of recognizing machining features from solid models. Existing work on recognition of features has focused exclusively on serial computer architectures. Our objective is to show that distributed algorithms can be employed on realistic parts with large numbers of features and many geometric and topological entities to obtain significant improvements in computation time using existing hardware and software tools. Migrating solid modeling applications toward a distributed computing frame-work enables interconnection of many of the autonomous and geographically diverse software tools used in the modern manufacturing enterprise.
This has been implemented on a network of SUN workstations using the ACIS solid modeler and the NIH C++ class library; inter-processor communication is handled with TCP/IP- based network communication tools.
Item Automated Manufacturability Analysis of Machined Parts(1995) Gupta, Satyandra K.; Zhang, G.M.; Nau, D.S.; ISRBecause of pressing demands to reduce lead time and product cost, increasing research attention is being given to integration of engineering design and manufacturing. In this thesis, a systematic approach has been developed for computer-aided manufacturability analysis of machined parts. This approach can be used during design stages to improve the product quality from the manufacturing point of view.Evaluating the manufacturability of a proposed design involves determining whether or not it is manufacturable with a given set of manufacturing operations - and if so, then finding the associated manufacturing efficiency. In this research, the design is represented as a solid model. The tolerance and surface finish information is represented as attributes of various faces of the solid model. Machining features are used to model the available machining operations Since there can be several different ways to manufacture a proposed design, this requires considering alternative ways to manufacture it, in order to determine which one best meets the design and manufacturing objectives.
The approach developed in this thesis is based on the systematic exploration of various machining plans. The first step is to identify all machining features which can potentially be used to machine the given design. Using these features, different machining plans are generated. Each time a new plan generated, it is examined to find whether it can produce the desired design tolerances. If a plan is found to be capable of meeting the tolerance specifications, then its rating is computed. If no machining plan can be found that is capable of producing the design, then the design cannot be machined using the given set of machining operations; otherwise, the manufacturability rating of the design is computed. Since various alternative ways of machining the part are considered in this approach, the conclusions about the manufacturability are more realistic compared to the approach where just one alternative is considered.
It is anticipated that this research will help in speeding up the evaluation of new product designs in order to decide how or whether to manufacture them. Such a capability will be useful in responding quickly to changing demands and opportunities in the marketplace.
Item Automated Manufacturability Analysis: A Survey(1995) Das, Diganta; Gupta, Satyandra K.; Regli, W.C.; Nau, Dana S.; ISRIn the marketplace of the 21st century, there is no place for traditional ``over-the-wall'' communications between design and manufacturing. In order to ``design it right the very first time,'' designers must ensure that their products are both functional and easy to manufacture. Software tools have had some successes in reducing the barriers between design and manufacturing. Manufacturability analysis systems are emerging as one such tool---enabling identification of potential manufacturing problems during the design phase and providing suggestions to designers on how to eliminate them.In this paper, we provide a survey of current state of the art in automated manufacturability analysis. We present the historical context in which this area has emerged and outline characteristics to compare and classify various systems. We describe the two dominant approaches to automated manufacturability analysis and overview representative systems based on their application domain. We describe support tools that enhance the effectiveness of manufacturability analysis systems. Finally, we attempt to expose some of the existing research challenges and future directions.
Item Building MRSEV Models for CAM Applications(1993) Gupta, Satyandra K.; Kramer, Thomas R.; Nau, D.S.; Regli, W.C.; Zhang, G.M.; ISRIntegrating CAD and CAM applications, one major problems is how to interpret CAD information in a manner that makes sense for CAM. Our goal is to develop a general approach that can be used with a variety of CAD and CAM applications for the manufacture of machined parts.In particular, we present a methodology for taking a CAD model, extracting alternative interpretations of the model as collections of MRSEVs (Material Removal Shape Element Volumes, a STEP-based library of machining features), and evaluating these interpretations to determine which one is optimal. The evaluation criteria may be defined by the user, in order to select the best interpretation for the particular application at hand.
Item Characterization and control of plastic deformation in premolded components in in-mold assembled mesoscale revolute joints using bi-directional filling strategy(2008-12) Ananthanarayanan, Arvind; Gupta, Satyandra K.; Bruck, HughItem Current Trends and Future Challenges in Automated Manufacturability Analysis(1995) Gupta, Satyandra K.; Das, Diganta; Regli, W.C.; Nau, Dana S.; ISRIn the marketplace of the 21st century, there is no place for traditional communications between design and manufacturing. In order to ``design it right the first time,'' designers must ensure that their products are both functional and easy to manufacture. Software tools have had some successes in reducing the barriers between design and manufacturing. Manufacturability analysis systems are emerging as one such tool---enabling identification of potential manufacturing problems during the design phase and providing suggestions to designers on how to eliminate them.In this paper, we survey of current state of the art in automated manufacturability analysis. We describe the two dominant approaches to automated manufacturability analysis and overview representative systems based on their application domain. Finally, we attempt to expose some of the existing research challenges and future directions.
Item A design framework for realizing multifunctional wings for flapping wing air vehicles using solar cells(SAGE Publications, 2019-04-10) Holness, Alex E.; Solheim, Hannah; Bruck, Hugh A.; Gupta, Satyandra K.Long flight durations are highly desirable to expand mission capabilities for unmanned air systems and autonomous applications in particular. Flapping wing aerial vehicles are unmanned air system platforms offering several performance advantages over fixed wing and rotorcraft platforms, but are unable to reach comparable flight times when powered by batteries. One solution to this problem has been to integrate energy harvesting technologies in components, such as wings. To this end, a framework for designing flapping wing aerial vehicle using multifunctional wings using solar cells is described. This framework consists of: (1) modeling solar energy harvesting while flying, (2) determining the number of solar cells that meet flight power requirements, and (3) determining appropriate locations to accommodate the desired number of solar cells. A system model for flapping flight was also developed to predict payload capacity for carrying batteries to provide energy only for power spikes and to enable time-to-land safely in an area where batteries can recharge when the sun sets. The design framework was applied to a case study using flexible high-efficiency (>24%) solar cells on a flapping wing aerial vehicle platform, known as Robo Raven IIIv5, with the caveat that a powertrain with 81% efficiency is used in place of the current servos. A key finding was the fraction of solar flux incident on the wings during flapping was 0.63 at the lowest solar altitude. Using a 1.25 safety factor, the lowest value for the purposes of design will be 0.51. Wind tunnel measurements and aerodynamic modeling of the platform determined integrating solar cells in the wings resulted in a loss of thrust and greater drag, but the resulting payload capacity was unaffected because of a higher lift coefficient. A time-to-land of 2500 s was predicted, and the flight capability of the platform was validated in a netted test facility.Item Design, Manufacturing, and Testing of Robo Raven(2014-04) Gerdes, John; Holness, Alex; Perez-Rosado, Ariel; Roberts, Luke; Barnett, Eli; Greisinger, Adrian; Kempny, Johannes; Lingam, Deepak; Yeh, Chen-Haur; Bruck, Hugh; Gupta, Satyandra K.Most current bird-inspired flapping wing air vehicles (FWAVs) use a single actuator to flap both wings. This approach couples and synchronizes the motions of the wings while providing a variable flapping rate at a constant amplitude or angle. Independent wing control has the potential to provide a greater flight envelope. Driving the wings independently requires the use of at least two actuators with position and velocity control. Integration of two actuators in a flying platform significantly increases the weight and hence makes it challenging to achieve flight. We used our successful previous designs with synchronized wing flapping as a starting point for creating a new design. The added weight of an additional actuator required us to increase the wing size used in the previous designs to generate additional lift. For the design reported in this paper, we took inspiration from the Common Raven and developed requirements for wings of our platform based on this inspiration. Our design process began by selecting actuators that can drive the raven-sized wing independently to provide two degrees of freedom over the wings. We concurrently optimized wing design and flapping frequency to generate the highest possible lift and operate near the maximum power operating point for the selected motors. The design utilized 3D printed parts to minimize part count and weight while providing a strong fuselage. The platform reported in this paper, known as Robo Raven, was the first demonstration of a bird-inspired platform doing outdoor aerobatics using independently actuated and controlled wings. This platform successfully performed dives, flips, and buttonhook turns demonstrating the capability afforded by the new design.Item Estimation of Achievable Tolerances(1993) Gupta, Satyandra K.; Nau, D.S.; Zhang, G.M.; ISRThis report presents a new and systematic approach to assist decision-making in selecting machining operation plans. We present a methodology to estimate achievable tolerances of operations plan. Given an operation plan, we use variety of empirical and mathematical models to evaluate process capabilities of various machining operations and compute achievable tolerances using tolerance charting techniques.Item Estimation of Setup Time for Machined Parts: Accounting for Work-Holding Constraints(1995) Das, Diganta; Gupta, Satyandra K.; Nau, Dana S.; ISRFor machined parts, setup time is a major component of the total time required to create a machined part. If the setup time can be reduced, this will not only decrease the machining time, but will also ensure better machining accuracy, require fewer work- holding devices and increase machine usage time.To achieve any improvement in setup time, first we need to estimate the setup time accurately. In this paper we propose a methodology to estimate the setup time for machining prismatic parts in a three axis vertical machining center. We consider three major factors in estimating the number of setups, namely---the precedence constraints among machining operations, the feasibility of work holding using vise clamping, and the availability of datum faces for locating the workpiece.
Item Evaluating Product Machinability for Concurrent Engineering(1992) Nau, D.S.; Zhang, G.M.; Gupta, Satyandra K.; Karinthi, Raghu R.; ISRDecisions made during the design of a machined part can significantly affect the product's cost, quality, and lead time. Thus, in order to address the goals of concurrent engineering, it is important to evaluate the machinability of the proposed design, so that the designer can change the design to improve its machinability, To determine the machinability of the part, all of the possible alternative ways to machine the part should be generated, and their machinability evaluated. This chapter describes the techniques we have developed to do this automatically.The information provided by these techniques will prove useful in two ways: (1) to provide information to the manufacturing engineer about alternative ways in which the part might be machined, and (2) to provide feedback to the designer identifying problems that may arise with the machining.
Item Extracting Alternative Machining Features: Al Algorithmic Approach(1994) Regli, W.C.; Gupta, Satyandra K.; Nau, D.S.; ISRAutomated recognition of features from CAD models has been attempted for a wide range of application domains. In this paper we address the problem of representing and recognizing the complete class of features in alternative interpretations for a given design. We present a formalism for representing feature- based design alternatives and a methodology for recognizing a class of machinable features. Our approach handles a class of volumetric features that describe material removal volumes made by operations on the three-axis vertical machining centers including: drilling, pocket-, slot-, and face-miling, chamfering, filleting, and blended surfaces. Our approach recognizes intersecting features, and is complete over all features in our class, i.e. for any given part, the algorithm produces a set containing all features in our class that correspond to possible operations for machining that part. This property is of particular significance in applications where consideration of different manufacturing alternatives is crucial. In addition, we have shown that the algorithms are, in the worst-case, euqdratic in the number solid modeling operations. This approach employs a class of machinable features expressible as MRSEVs ( a STEP- based library of machining features). An implementation of these algorithms has been done using the ACISsolid modeler and the NIH C++ class library.Item A Feature Based Approach to Automated Design of Multi-Piece Sacrificial Molds(2000) Dhaliwal, Savinder; Gupta, Satyandra K.; Huang, Jun; Kumar, Malay; ISRThis report describes a feature-based approach to automated design of multi-piece sacrificial molds. We use multi-piece sacrificial molds to create complex 3D polymer/ceramic parts. Multi-piece molds refer to molds that contain more than two mold components or subassemblies.Our methodology has the following three benefits over the state-of-the-art. First, by using multi-piece molds we can create complex 3D objects that are impossible to create using traditional two piece molds. Second, we make use of sacrificial molds. Therefore, using multi-piece sacrificial molds, we can create parts that pose disassembly problems for permanent molds. Third, mold design steps are significantly automated in our methodology. Therefore, we can create the functional part from the CAD model of the part in a matter of hours and so our approach can be used in small batch manufacturing environments.
The basic idea behind our mold design algorithm is as follows. We first form the desired gross mold shape based on the feature-based description of the part geometry. If the desired gross mold shape is not manufacturable as a single piece, we decompose the gross mold shape into simpler shapes to make sure that each component is manufacturable using CNC machining. During the decomposition step, we account for tool accessibility to make sure that (1) each component is manufacturable, and (2) components can be assembled together to form the gross mold shape. Finally, we add assembly features to mold component shapes to facilitate easy assembly of mold components and eliminate unnecessary degree of freedoms from the final mold assembly.
Item Feature Recognition for Interactive Applications: Exploiting Distributed Resources(1998-10-15) Regli, William C.; Gupta, Satyandra K.; Nau, Dana S.The availability of low-cost computational power is a driving force behind the growing sophistication of CAD software. Tools designed to reduce time-consuming build-test-redesign iterations are essential for increasing engineering quality and productivity. However, automation of the design process poses many difficult computational problems. As more downstream engineering activities are being considered during the design phase, guaranteeing reasonable response times within design systems becomes problematic. Design is an interactive process and speed is a critical factor in systems that enable designers to explore and experiment with alternative ideas during the design phase. Achieving interactivity requires an increasingly sophisticated allocation of computational resources in order to perform realistic design analyses and generate feedback in real time. This paper presents our initial efforts to develop techniques to apply distributed algorithms to the problem of recognizing machining features from solid models. Existing work on recognition of features has focused exclusively on serial computer architectures. Our objective is to show that distributed algorithms can be employed on realistic parts with large numbers of features and many geometric and topological entities to obtain significant improvements in computation time using existing hardware and software tools. Migrating solid modeling applications toward a distributed computing framework enables interconnection of many of the autonomous and geographically diverse software tools used in the modern manufacturing enterprise. (Also cross-referenced as UMIACS-TR-94-126.1)Item Feature Recognition for Manufacturability Analysis(1994) Regli, W.C.; Gupta, Satyandra K.; Nau, D.S.; ISRWhile automated recognition of features has been attempted for a wide range of applications, no single existing approach possesses the functionality required to perform manufacturability analysis. In this paper, we present a methodology for taking a CAD model and extracting a set of machinable features suitable for generating all alternative interpretations of the model as collections of MRSEVs (Material Removal Shape Element Volumes, a STEP-based library of machining, features). This set of MRSEVs is to be employed for manufacturability analysis. The algorithm handles a variety of features including those describing holes, pockets, slots, and chamfering and filleting operations. In addition, it considers elementary accessibility constraints for these features and is provably complete over a, significant class of machinable parts the features describe. Further, the approach has low-order polynomial-time worst-case complexity.Item Generating 3D Models of MEMS Devices by Process Emulation(2002) Bellam, S.; Gupta, Satyandra K.; Priyadarshi, A.K.; ISRMEMS designers often use numerical simulation for detecting errors in the mask layout. Numerical simulation involves generating 3D models of MEMS device from the mask layout and process description. The generated models can be meshed and simulated over different domains. This report describes an efficient algorithm that can generate 3D geometric models of MEMS devices. Specifically, the algorithm emulates the manufacturing of a single functional polysilicon layer MEMS devices using the MUMPSprocess.Item Generating Redesign Suggestions to Reduce Setup Cost: A Step towards Automated Redesign(1995) Das, Diganta; Gupta, Satyandra K.; Nau, Dana S.; ISRAll mechanical designs pass through a series of formal and informal redesign steps, involving the analysis of functionality, manufacturability, cost and other life-cycle factors. The speed and efficacy of these steps has a major influence on the lead time of the product from conceptualization to launching. In this paper we propose a methodology for automatically generating redesign suggestions for reducing setup costs for machined parts.Given an interpretation of the design as a collection of machinable features, our approach is to generate alternate machining features by making geometric changes to the original features, and add them to the feature set of the original part to create an extended feature set. The designer may provide restrictions on the design indicating the type and extent of modifications allowed on certain faces and volumes, in which case all redesign suggestions generated by our approach honor those restrictions.
By taking combinations of features from the extended feature set generated above, we can generate modified versions of the original design that still satisfy the designer's intent. By considering precedence constraints and approach directions for the machining operations as well as simple fixturability constraints, we can estimate the setup time that will be required for each design. Any modified design whose setup time is less than that of the original design can be presented to the designer as a possible way to modify the original design.
Item Generation and Evaluation of Alternative Operation(1992) Nau, D.S.; Zhang, G.M.; Gupta, Satyandra K.; ISRThis paper presents a new and systematic approach to assist decision-making in selecting machining operation sequences. The approach is to produce alternative interpretations of design as different collections of machinable features, use these interpretations to generate alternative machining operation sequences, and evaluate the cost and achievable machining accuracy of each operations sequence. Given the operation sequences and their evaluations, it is then possible to calculate the performance measures of interest, and use these performance measures to select, from among the various alternatives, one or more of them that can best balance the need for a quality product against the need for efficient machining.Item Generation of Machining Alternatives for Machinability Evaluation(1992) Gupta, Satyandra K.; Nau, D.; Zhang, G.M.; ISRThis paper presents a new methodology for evaluating the machinability of a machined part during the design stage of the product development cycle, so that problems related to machining can be recognized and corrected while the product is being designed. Our basic approach is to perform a systematic evaluation of machining alternatives throughout each step in the design stage. This involves three basic steps: (1) generate alternative interpretations of the design as different collections of machinable features, (2) generate the various possible sequences of machining operations capable of producing each interpretation, and (3) evaluate each operation sequence, to determine the relevant information on achievable quality and associated costs. The information provided by this analysis can be used not only to give feedback to the designer about problems that might arise with the machining, but also to provide information to the manufacturing engineer about alternative ways in which the part might be machined.
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