Satyandra K. Gupta

A Survey of Shape Similarity Assessment Algorithms for Product Design and Manufacturing Applications

Shape similarity assessment is a fundamental geometric reasoning problem that finds application in several different product design and manufacturing applications. A computationally efficient way to assess shape similarity is to first abstract 3D object shapes into shape signatures and use shape signatures to perform similarity assessment. Several different types of shape signatures have been developed in the past. This paper provides a survey of existing algorithms for computing and comparing shape signatures. Our survey consists of a description of the desired properties of shape signatures, a scheme for classifying different types of shape signatures, and descriptions of representative algorithms for computing and comparing shape signatures. This survey concludes by identifying directions for future research. 1 Corresponding Author

Automated manufacturability analysis: a survey

In the market-place 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 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.

A survey of CAD model simplification techniques for physics-based simulation applications

Automated CAD model simplification plays an important role in effectively utilizing physics-based simulation during the product realization process. Currently a rich body of literature exists that describe many successful techniques for fully-automatic or semi-automatic simplification of CAD models for a wide variety of applications. The purpose of this paper is to compile a list of the techniques that are relevant for physics-based simulations problems and to characterize them based on their attributes. We have classified them into the following four categories: techniques based on surface entity based operators, volume entity based operators, explicit feature based operators, and dimension reduction operators. This paper also presents the necessary background information in the CAD model representation to assist the new readers. We conclude the paper by outlining open research directions in this field.

Systematic approach to analysing the manufacturability of machined parts

Abstract The ability to quickly introduce new quality products is a decisive factor in capturing market share. Because of pressing demands to reduce leadtimes, analysing the manufacturability of the proposed design has become an important step in the design stage. The paper presents an approach to analysing the manufacturability of machined parts. Evaluating the manufacturability of a proposed design involves determining whether or not it is manufacturable with a given set of manufacturing operations, and, if it is, finding the associated manufacturing efficiency. Since there can be several different ways to manufacture a proposed design, this requires that different ways to manufacture it be considered, in order to determine which one best meets the design and manufacturing objectives. The first step in the approach is to identify all the machining operations which can potentially be used to create the given design. Using these operations, different operation plans are generated for machining the part. Each time a new operation plan is generated, the user examines whether it can produce the desired shape and tolerances, and calculates its manufacturability rating. If no operation plan can be found that is capable of producing the design, then the given design is considered unmachinable; otherwise, the manufacturability rating for the design is the rating of the best operation plan. The authors expect that, by providing feedback about possible problems with the design, the work described in the paper will help in speeding up the evaluation of new product designs so that it can be decided how or whether to manufacture them. Such a capability will be useful in responding quickly to changing demands and opportunities in the marketplace.

A survey of snake-inspired robot designs

Body undulation used by snakes and the physical architecture of a snake body may offer significant benefits over typical legged or wheeled locomotion designs in certain types of scenarios. A large number of research groups have developed snake-inspired robots to exploit these benefits. The purpose of this review is to report different types of snake-inspired robot designs and categorize them based on their main characteristics. For each category, we discuss their relative advantages and disadvantages. This review will assist in familiarizing a newcomer to the field with the existing designs and their distinguishing features. We hope that by studying existing robots, future designers will be able to create new designs by adopting features from successful robots. The review also summarizes the design challenges associated with the further advancement of the field and deploying snake-inspired robots in practice.

Towards the development of a virtual environment-based training system for mechanical assembly operations

In this paper, we discuss the development of Virtual Training Studio (VTS), a virtual environment-based training system that allows training supervisors to create training instructions and allows trainees to learn assembly operations in a virtual environment. Our system is mainly focused on the cognitive side of training so that trainees can learn to recognize parts, remember assembly sequences, and correctly orient the parts during assembly operations. Our system enables users to train using the following three training modes: (1) Interactive Simulation, (2) 3D Animation, and (3) Video. Implementing these training modes required us to develop several new system features. This paper presents an overview of the VTS system and describes a few main features of the system. We also report user test results that show how people train using our system. The user test results indicate that the system is able to support a wide variety of training preferences and works well to support training for assembly operations.

Automated process planning for sheet metal bending operations

Abstract This paper describes a generative process planning system for robotic sheet metal bending press brakes. This process planning system employs a distributed planning architecture. Currently, the system consists of a central operation planner and three specialized domain-specific planners: tooling, grasping, and moving. The central operation planner proposes various alternative partial sequences, and each specialized planner evaluates these sequences based on its objective function. The central operation planner uses state-space search techniques to optimize the operation sequence. Once a CAD design is given for a new part, the system automatically determines: the operation sequence, the tools and robot grippers needed, the tool layout, the grasp positions, the gage, and the robot motion plans for making the part. The distributed architecture allows the development of an open-architecture environment for doing generative process planning and encapsulating the specialized knowledge in specialized planners.

Extracting alternative machining features: An algorithmic approach

Automated recognition of features from CAD models has been attempted for a wide range of application domains. In this article we address the problem of representing and recognizing a complete class of features in alternative interpretation for a given design.We present a methodology for recognizing a class of machinable features and addressing the computational problems posed by the existence of feature-based alternatives. Our approach addresses a class of volumetric features that describe material removal volumes made by operations on three-axis vertical machining centers, including drilling, pocket-milling, slot-milling, face-milling, chamfering, filleting, and blended surfaces.This 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.This approach employs a class of machinable features expressible as MRSEVs (a STEP-based library of machining features). An example of this methodology has been implemented using the ACIS solid modeler and the National Institutes of Health C++ class library.

Developing a Stochastic Dynamic Programming Framework for Optical Tweezer-Based Automated Particle Transport Operations

Automated particle transport using optical tweezers requires the use of motion planning to move the particle while avoiding collisions with randomly moving obstacles. This paper describes a stochastic dynamic programming based motion planning framework developed by modifying the discrete version of an infinite-horizon partially observable Markov decision process algorithm. Sample trajectories generated by this algorithm are presented to highlight effectiveness in crowded scenes and flexibility. The algorithm is tested using silica beads in a holographic tweezer set-up and data obtained from the physical experiments are reported to validate various aspects of the planning simulation framework. This framework is then used to evaluate the performance of the algorithm under a variety of operating conditions.

Geometric algorithms for automated design of multi-piece permanent molds

Abstract Multi-piece molds, which consist of more than two mold pieces, are capable of producing very complex parts—parts that cannot be produced by the traditional molds. The tooling cost is also low for multi-piece molds, which makes it a candidate for pre-production prototyping and bridge tooling. However, designing multi-piece molds is a time-consuming task. This article describes geometric algorithms for automated design of multi-piece molds. A multi-piece mold design algorithm has been developed to automate several important mold-design steps: finding parting directions, locating parting lines, creating parting surfaces, and constructing mold pieces. This algorithm constructs mold pieces based on global accessibility analysis results of the part and therefore guarantees the disassembly of the mold pieces. A software system has been developed, which has been successfully tested on several complex industrial parts.