bluuebunny/crossref_metadata_2025 huggingface dataset:
Finding the Maximal Cutter for 2-D Milling Operations
Authors: Yao Zhiyang , Gupta Satyandra K. , Nau Dana S.
Published: December 2020

Finding the biggest cutter is expected to help in the selection of the right sets of tools and the right type of cutter trajectories, and thereby ensure high production rate and meet the required quality level. In this paper, we describe a new geometric algorithm to determine the biggest feasible cutter size for 2-D milling operations to be performed using a single cutter. Our algorithm works not only for the common closed pocket problem, but also for the general 2-D milling problems with open edges. In particular:

• We give a general definition of the problem as the task of covering a target region without interfering with an obstruction region. This definition encompasses the task of milling a general 2-D profile that includes both open and closed edges.

• We discuss three alternative definitions of what it means for a cutter to be feasible, and explain which of these definitions is most appropriate for the above problem.

• We present a geometric algorithm for finding the maximal cutter for 2-D milling operations, and we give an outline of a proof that our algorithm is correct.
Feature Validity Maintaining Based on Local Feature Recognition
Authors: Gao Shuming , Chen Zhengming , Peng Qunsheng
Published: December 2020

Lack of feature validity maintenance function is recognized as a serious problem with current feature modeling system, which makes feature modeling just like an advanced geometric modeling with parametric and constraint-based modeling facilities.

In this paper, we present a novel approach to feature validity maintaining. The approach detects the topologically destroyed features and determine the new states of the destroyed features by performing local feature recognition on the area of the part which consists of all the boundary entities of the edited feature and the features intersecting with the edited feature after a feature is edited. In the approach, feature conversion and feature mergence are distinguished from the real destruction of feature validity to let the user have chances to determine if the feature conversion or feature mergence is what he/she wants. To make the implementation of the approach easy, a representation for topologic validity conditions based on the extended attributed adjacency graph is adopted.
Integrated Local and Global Tool Path Planning for Feature-Based Machining
Authors: Wang Eric , Hwang Il-Kyu , Kim Yong Se
Published: December 2020

We describe an automatic machining tool path generation method that combines local tool path planning for machining features with global tool path planning. From the solid model and the tolerance specifications of the part, machining features are automatically recognized, and geometry-based precedence relations are obtained between these features. From this information, the machining sequence, tool selections, and machining conditions are determined. Machining tool paths are then generated automatically for each setup, combining local and global tool paths. Local tool paths to machine each feature are generated using successive offsetting operations. Global tool paths between features are generated incrementally by searching the adjacency graph of feature free spaces, which represents the current free space of the part. Feature free spaces are obtained by expanding the machining features through their fictitious faces. The start and end positions for the local tool paths of each feature are selected based on a heuristic method to minimize the cost of each segment of the global tool path. This automatic tool path generation method is currently being developed as part of a comprehensive machining process planning system.
Tool-Path Generation in Three-Axis Machining From Scanned Data of Physical Models by Using Filleted Endmills
Authors: Chuang Cheng-Ming , Chen Chun-Yan , Yau Hong-Tzong
Published: December 2020

NC tool-path is usually generated by sweeping parametric surfaces of a CAD model. In modern design, free-form or sculptured surfaces are increasingly popular in representing complex geometry for aesthetic or functional purposes. Traditionally, a prototype is realized by machining the workpiece using the NC codes generated from a CAD model. The machined part can then be compared with the CAD model by measurement using a coordinate measuring machine. Presented in this paper is a reverse engineering approach to generating interference free tool-paths in three-axis machining from scanned data of physical models. There are two steps in this procedure. First, a physical model is scanned by 3D digitizers and multiple data sets are obtained of the complex model. A surface registration algorithm is proposed to align and integrate those data to construct a complete 3D data set. We use least distance method to determine the connecting sequence of the neighboring points, such that the scanned data are converted into triangular polygons. Tool-paths are then generated from the tessellated surfaces. Using the Z-map method we calculate interference-free cutter-location data relative to the vertex, edges and planes of those triangles. The algorithms for tool-path generation are usually different for cutters of various geometry. Some algorithms found in literature require complex numerical calculations and are time consuming. In this paper, an efficient algorithm is developed to calculate interference-free cutter-location data by easy geometric reasoning without complex computation. The robust method is suitable for generally used cutters such as ball, flat and filleted endmills and the time taken to obtain full tool-paths of compound surfaces is short. Some real applications are presented to validate the proposed approach.
Non-Linear and Non-Stationary Random Responses of Discretized Plate Structures by Stochastic Direct Integration With Correction Factor
Authors: Liu M. L.
Published: December 2020

The investigation reported in this paper is to further improve the effectiveness of some stochastic direct integration schemes. These stochastic direct integration schemes were proposed to compute response statistics, such as mean squares and variances of generalized displacements, of large discretized structures undergoing large non-linear deformation and under non-stationary random excitation. First of all, the stochastic Newmark method is extended to include the stochastic as well as the deterministic excitations. Next, a correction factor that is to be applied to the discrete white noise is introduced. The stability criterion is then examined. The advantage of introducing such a correction factor is that one is not limited to those time step sizes that have been found to yield accurate response statistics in previous investigations. Instead, one can choose a time step size in the way he may in an analysis using the deterministic Newmark method. The correction factor is determined based on this chosen time step size, thus providing the flexibility in balancing the needs of accuracy and effectiveness. Subsequently, the hybrid strain based three-noded flat triangular shell element, single- or multi-layered, is employed to model selected plate structures. These numerical examples demonstrate the accuracy and effectiveness of the proposed methodology.
An Intelligent Manufacturing System for Predictive Scheduling and Reactive Scheduling
Authors: Sun J. , Xue D. , Norrie D. H.
Published: December 2020

This research introduces an intelligent, distributed approach for predictive scheduling and reactive scheduling. Product descriptions and their manufacturing requirements are represented using a feature-based modeling scheme. Manufacturing resources, including facilities and persons, are modeled as agents. In predictive scheduling, the optimal production schedule is identified through heuristic search and agent-based negotiation. In reactive scheduling, the original schedule is modified for responding to the changes of orders and resources through a match-up approach and agent-based negotiation, when the original schedule cannot be accomplished due to these changes.
A Mathematical Model for Predicting Conditions That Prevent Gaseous Fuel-Air Mixing
Authors: Brasoveanu Dan , Gupta Ashwani K.
Published: December 2020

A unified model is used here to determine the distributions of pressure, temperature and velocity that reduce gaseous fuel-air mixing. The model uses the fuel mass fraction within infinitesimal fluid elements and the total derivative of this fraction with respect to time to quantify the degree and rate of mixing, respectively. An Eulerian representation is used. The model is valid for gaseous fuels that contain a single chemical species and for low-pressure combustors. The model permits the presence of only trace amounts of combustion products within the mixing region. Aside from these restrictions, the mixing model can be applied to a variety of combustor designs and operational conditions. Results show that certain distributions of pressure, temperature and velocity at the fuel-air boundary reduce or even prevent gaseous fuel-air mixing, in particular whenever the logarithmic rate of temperature and the velocity divergence are comparable. These conditions yield low intensity and efficiency combustion as well as high pollutants emission level.
Treatment of the Responsibility and Controllability in Team-Based Concurrent Product and Process Design
Authors: Chen Li , Li Simon
Published: December 2020

In team-based concurrent product and process design (CPPD), one type of team activities proceeds alternately in a one-by-one fashion. This sequential mode of design flow can be treated as a generalized leader/follower team paradigm, in which the leader acts as a principal team and the follower as a subordinate team. In the dual-team approach, the leader and the follower correspond to two aspects of CPPD — product design and process design — whereby the alternate nature of design tasks can be characterized through the interactions of the leader and the follower. To reveal the variety of such team activities, the notion of responsibility and controllability in various design protocols is introduced to describe the respective roles of the leader and the follower in team design. The method of Design for Satisfaction (DfS) is used as a framework to characterize team’s preference toward a feasible design in view of the team’s goal. Accordingly, the satisfaction-driven dual-team based CPPD models are developed to account for different team scenarios. A design example is used to support the illustration of the team design approach suggested.
A Hybrid Fuzzy Simplex Genetic Algorithm
Authors: Trabia Mohamed B.
Published: December 2020

Nelder and Mead Simplex (NMS) algorithm is an effective nonlinear programming technique. Trabia and Lu (1999) recently presented a novel algorithm, Fuzzy Simplex (FS), which improved the efficiency of Nelder and Mead Simplex by using fuzzy logic to determine the orientation and size of the simplex. While Fuzzy Simplex algorithm can be successfully used to search a wide variety of functions, it suffers, as other simplex algorithms, from its dependence on the initial guess and the original simplex size. This paper addresses this problem by combining the Fuzzy Simplex with Genetic Algorithm (GA) in a hybrid algorithm. Standard test problems are used to evaluate the efficiency of the algorithm. The algorithm is also applied successfully to several engineering design problems. The Hybrid GA Fuzzy Simplex algorithm generally results in a faster convergence.
An Introduction to Adaptive Robust Design for Mechanical Assemblies
Authors: Parkinson Alan R. , Chase Kenneth W.
Published: December 2020

This paper introduces a relatively new area of robust design we choose to call adaptive robust design. An adaptive robust design has features, not otherwise required by the function of the design, which allow the design to absorb or cancel out the effects of variation. A passive adaptive robust design (or just “passive design” for short) requires external adjustment or setting; passive designs are usually set at the factory but may also be adjustable in the field. An active adaptive robust design (or “active” design) can automatically adapt itself to variation which changes over time. We discuss adaptive robust design as applied to mechanical assemblies. A framework for research in this area is presented. We also discuss the relationship of adaptive design to other robust design methods.
A Multi-Level Genetic Assembly Planner
Authors: Chen Shiang-Fong , Liu Yong-Jin
Published: December 2020

Assembly sequence planning (ASP) is a combinatorial optimization problem with highly non-linear geometric constraints. Most proposed methodologies are based on graph theory and involve complex geometric and physical analysis. As a result, even for a simple structure, it is difficult or impossible to take all important criteria into consideration. In order to bring assembly sequence planning closer to real-world application, this paper proposes a genetic planner for efficiently finding global-optimal assembly sequences. To optimize our genetic-algorithm-based approach, we propose a hierarchical genetic structure and an evaluation mechanism for dynamically adapting control parameters in our hierarchical structure. Unlike conventional genetic algorithms, which use static genetic operator probability settings (GOPS), our hierarchical genetic planner searches for optimal assembly sequences in a low-level GA and manipulates low-level GOPS using a high level GA. Conventional “GA within GA” approaches perform, for every high-level generation, a full low-level GA run, whereas our multi-level GA uses a high-level GA to isochronously update low-level GA control parameters during each low-level GA run. Experimental results show that our multi-level genetic assembly sequence planner solves combinatorial ASP problems quickly, reliably, and accurately.
Decision-Based Collaborative Optimization Under Uncertainty
Authors: Gu Xiaoyu , Renaud John E. , Ashe Leah M. , Batill Stephen M. , Budhiraja Amarjit S. , Krajewski Lee J.
Published: December 2020

In this research a Collaborative Optimization (CO) approach for multidisciplinary systems design is used to develop a decision based design framework for non-deterministic optimization. To date CO strategies have been developed for use in application to deterministic systems design problems. In this research the decision based design (DBD) framework proposed by Hazelrigg (1996a, 1998) is modified for use in a collaborative optimization framework. The Hazelrigg framework as originally proposed provides a single level optimization strategy that combines engineering decisions with business decisions in a single level optimization. By transforming the Hazelrigg framework for use in collaborative optimization one can decompose the business and engineering decision making processes. In the new multilevel framework of Decision Based Collaborative Optimization (DBCO) the business decisions are made at the system level. These business decisions result in a set of engineering performance targets that disciplinary engineering design teams seek to satisfy as part of subspace optimizations. The Decision Based Collaborative Optimization framework more accurately models the existing relationship between business and engineering in multidisciplinary systems design.
Visualization and Comparison of Solution Paths With Artificial Metrics
Authors: Rudolph Stephan
Published: December 2020

The use of graph theoretical concepts, which can bridge the gap between the construction of verbal and simple analytical design model representations, is explored. Graph methods offer the possibility to process both verbal and analytical object information, since in either case the identification of the objects represented is achieved using an identifier concept, which relies on pattern matching techniques. The comparison of different solution paths for the same conceptual design problem using artificial metrics is shown in a case study. The results show that the solution paths for the analytical model based on the complete set of analytical equations can already be determined and analyzed using a verbal description model. Furthermore, both solution paths of the analytical and the verbal model are identical, if the relevance lists of the verbal design descriptions are complete.
On the Link Between Design Against Fatigue and Fracture Mechanics
Authors: Debongnie J. F.
Published: December 2020

The gradient method, often used in design against fatigue, is analyzed from the point of view of its link with fracture mechanics. By a logical step, a law is deduced for the variation of the endurance limit in terms of the relative stress gradient. The proposed expression is found to be in good agreement with older ones and may easily be extended to a large class of materials.
Robust Design Using Fuzzy Numbers: Consideration of Correlation of Design Variables in Fuzzy Operation
Authors: Arakawa Masao , Yamakawa Hiroshi , Ishikawa Hiroshi
Published: December 2020

These days robust design has become more and more important to raise reliability in the products under many kinds of imprecision, including human errors, modeling errors and so on. In the past, robust design only tries to obtain the robust design variables that have less sensitivity with quasi-optimum solutions. Recently, many researchers try to design not only of design variable’s value but also to its deviations. Which means that robust design tries to have wider range of design variables and still keeps robustness in the design. For the simplicity of calculation, most of them assume independence of design variables, thus, the ranges are determined by their upper and lower bound. However, in the real design almost every design variables are not independent with the influence of constraints. In this study, we will newly propose the method that can determine the relationships of design variables, something like correlation of design variables. We will show the effectiveness of the method by some numerical examples.
Numerical Kinematic Analysis of the MacPherson Strut Motor-Vehicle Suspension System
Authors: Attia Hazem A. , Mohamed Maher G.
Published: December 2020

In the present paper, an efficient numerical algorithm for the kinematic analysis of the multi-loop MacPherson Strut suspension system is formulated. The suspension system is usually used for front as well as axles of current car productions. The spatial two-DOF multi-loop MacPherson Strut suspension mechanism contains all types of basic kinematic joints; revolute, prismatic, and spherical joints. The kinematic analysis is carried out in terms of the rectangular Cartesian coordinates of some defined points in the links and at the joints. The presented formulation in terms of this system of coordinates is simple and involves · only elementary mathematics. A numerical example is presented.
Approximate Life-Cycle Assessment in Conceptual Product Design
Authors: Eisenhard Julie L. , Wallace David R. , Sousa Ines , De Schepper Mieke S. , Rombouts Jeroen P.
Published: December 2020

Prior work has demonstrated the integration of detailed life-cycle assessment into a traditional design modeling process. While a full life-cycle assessment provides insight into a product’s potential impact on the environment, it is often too time consuming for analysis during conceptual product design, where ideas are numerous and information is scarce. The work presented in this paper explores an approximate method for preliminary life-cycle assessments without detailed modeling requirements. Learning algorithms trained on the known characteristics of existing products allow the environmental impacts of new products to be approximated quickly during conceptual design. Artificial neural networks train on product attributes and environmental impact data from pre-existing life-cycle assessment studies. The product design team queries the trained artificial model with new high-level product attribute data to quickly obtain an approximate impact assessment for a new product concept. Tests based on simplified inventory data have shown it is possible to predict impacts on life-cycle energy consumption, and that there is a basis for the method to be used in also predicting solid material, greenhouse effect, ozone layer depletion, acidification, eutrophication, winter smog, and summer smog.
FixtureScout: Restructuring Process Planning and Fixturing Decisions
Authors: Hayes Caroline C. , Veretennikov Aleksey
Published: December 2020

This paper describes FixtureScout, a program that performs a high-level clamp and clamping surface analysis very early in the planning process. FixtureScout’s function is not to perform detailed fixture planning, but to find clamping surface information that will help in determining the setup sequence. This information is important in sequencing because it allows the planner to determine which setups destroy the clamping surfaces required by another. FixtureScout is a component of a larger process planning architecture, MAPP, which explores various ways of re-organizing the decisions and information flow in feature extraction and process planning, for example, by moving Fixture Scouts’ clamping surface analysis to a very early stage of planning. Our goal is to to improve planning effectiveness through these re-organizations.
Octree Based Recognition of Assembly Features
Authors: Sung Raymond C. W. , Corney Jonathan R. , Clark Doug E. R.
Published: December 2020

This paper reviews the nature and use of assembly features. One of the conclusions drawn from this survey is that the majority of assembly features involve sets of spatially adjacent faces. Two principle types of adjacency relationships are identified and an algorithm is presented for identifying assembly features, these are features which arise from these “spatial” and “contact” face adjacency relationships (known as s- and c-adjacency respectively).

The algorithm uses an octree representation of a B-rep model to support the geometric reasoning required to locate assembly features on disjoint bodies. Once all the adjacent faces which form features have been located, they are used to partition the original faces of the assembly into adjacent and non-adjacent portions. The resulting system can locate and partition spatially adjacent faces in a wide range of situations and at different resolutions. By way of illustration, the algorithm is applied to a trial component.
Multi-Fixture Assembly System Diagnosis Based on Part and Subassembly Measurement Data
Authors: Carlson Johan S. , Lindkvist Lars , Söderberg Rikard
Published: December 2020

A method for multi-fixture assembly system diagnosis is presented. The subassembly dimensional error in the plane of rigidity caused by the fixtures is isolated using both part and subassembly measurement data. The error is explained by either a multiple locator fault in a specified fixture or by a single locator fault in an unspecified fixture. By means of this method the trouble shooting dimensional error efforts in an assembly plant can become more efficient and successful.
Activities in Collaborative Concept Selection Processes for Engineering Design
Authors: Girod Maurice , Elliott Amanda C. , Wright Ian C. , Burns Neil D.
Published: December 2020

The aims of this paper are (i) to introduce a set of activities found to occur during collaborative concept selection processes in engineering design; (ii) to discuss implications of their observed time contributions to such processes; and (iii) to describe the methodology used for this research. We identified a set of 12 main activities of which some were further divided into sub-activities. Their time contributions led us to 5 observations regarding some characteristics of the observed processes. In 3 workshops groups of differently experienced participants were recorded while carrying out concept selection tasks. The recordings were transcribed and a content analysis was conducted to identify the activities. Our findings may be further used as foundation for establishing a descriptive model of concept selection processes in engineering design.
A Performance-Based Representation of Constraint Based Reasoning and Decision Based Design
Authors: Zhu Liang , Kazmer David
Published: December 2020

A performance-based representation is developed utilizing multi-dimensional clipping and transformation algorithms. Given analytic performance functions, three types of supporting information is presented to the decision maker: 1) a function matrix that describes the performance attributes varying with the decision variables; 2) a decision space that illustrates the feasible decision set that meets performance requirements, and; 3) a performance space that provides the feasible performance region and the Pareto Optimal set. The performance-based representation is compatible with other influential design methodologies. A case study is presented for aircraft beam design utilizing constraint based reasoning and decision based design. The results demonstrate not only the benefit of the representation on interactive parametric design, but also an intriguing comparison between constraint based reasoning and decision based design approaches incorporated with the described representation. While a linearized parametric design problem is implemented, the approach shows a potential extension to non-linear systems.
A Proposed Framework for Research in Forming Successful Engineering Design Teams
Authors: Magleby Spencer P. , Roach Gregory M. , Sorensen Carl D.
Published: December 2020

Most engineering design is performed by teams. Team formation from a pool of competent designers and engineers is an important factor in helping determine performance potential. This paper is proposes a framework that we have developed to help guide research, and highlights challenges and obstacles that must be addressed in order to improve results in team formation research. A basic framework is presented and used as a basis for reviewing past work in team formation studies. This framework is then expanded to include explicit decisions about team formation and experimental strategy. Three important aspects of the framework that are critical to obtaining significant results about team formation are discussed: experimental strategy, success measures, and the separation of team formation effects from environmental effects. Recommendations for improvement in these areas are presented.
Guidelines for Experimental Evaluation of Idea Generation Methods
Authors: Shah Jami J. , Kulkarni Santosh V. , Vargas-Hernández Noé
Published: December 2020

Several formal Idea Generation (IG) methods can be found in the design literature ranging from simple methods like brainstorming to complex procedures such as synectics. Experimental evidence is needed to support claims regarding the effectiveness of these methods in promoting idea generation. This paper attempts to prescribe a method for evaluating intuitive idea generation methods. The set of guidelines for experimental evaluation include metrics, how to measure against those metrics (quality, quantity, novelty, variety), how to compute the results, and types of experiments to run. Statistically based Design of Experiments (DOE) principles are in developing the guidelines. Four classes of variables are considered. Two experiment methodologies are proposed. In the Direct Method experiments are conducted using the idea generation method in its entirety. In the Indirect Method, each idea generation method is decomposed into key components and its effectiveness is predicted by experimentally studying the effectiveness of its components and interactions between them.
Validating Design Methods and Research: The Validation Square
Authors: Pedersen Kjartan , Emblemsvåg Jan , Bailey Reid , Allen Janet K. , Mistree Farrokh
Published: December 2020

Validation of engineering research is typically anchored in the scientific inquiry tradition that is based primarily on logical induction and / or deduction. Since much engineering research is based on mathematical modeling, this kind of validation has worked — and still works — very well. There are, however, other areas of engineering research that rely on subjective statements as well as mathematical modeling, which makes this type of validation problematic. One such area is that of design methods within the field of engineering design. In this paper, we explore the question of how one validates design research in general, and design methods in particular.

Being anchored in the scientific inquiry tradition, research validation is strongly tied to a fundamental problem addressed in epistemology, namely, what is scientific knowledge and how is new knowledge confirmed? Thus, we first look to epistemology for answers to why an approach solely based on ‘formal, rigorous and quantifiable’ validation constitutes a problem, and for an augmented approach to research validation. We then propose the ‘Validation Square’ which we validate by testing its internal consistency based on logic in addition to testing its external relevance based on its usefulness with respect to a purpose.

We recognize that no one has the complete answer to the question we pose. To help us converge on an answer to these questions we “think aloud” and invite you to join us in doing the same. It is our hope that in so doing we, the members of this design research community, will all be the richer for it.
State Library Materials Handling System Design: Part II
Authors: Derby Stephen , Simon Matthew P. , Puffer Raymond H. , Allen Mark A. , Shone Tristan M. , Winston Jeremy B. , Judd Van
Published: December 2020

This paper (part two of two) discusses the concepts generated by the Center for Automation Technologies, Rensselaer Polytechnic Institute, for an automation system for the New York State Talking Book and Braille Library (TBBL). It describes the last several module concepts in the system, designed to assist the TBBL staff in the processing of “talking books” (books on cassette), and discusses system simulations, and conclusions from this work. Part one discussed the assessment of needs, requirements, and process flow (all of which are summarized here), as well as the first several modules in the system.

The primary purposes for this modular system are 1. To assist the TBBL in meeting increased throughput demands and 2. To reduce work-related injury claims. The modules are designed to work individually (as to allow the possibility of similar libraries in other states to purchase modules as desired), and facilitate incremental implementation toward a complete system (for maximized benefit).

In this paper, the modules discussed are the latch closer, label remover, and the virtual turnaround shelves system.
Agile Automation Control Systems: The Hansford Assembly Flex Project
Authors: Durante Ryan , Derby Stephen
Published: December 2020

This paper reviews the Hansford Assembly Flex project recently conducted at RPI. Assembly Flex is a modular automation assembly system in the truest sense. It most cases it can be reconfigured (re-tooled) in under 20 minutes and go from building water pumps to car stereos. Much of this flexibility stems from its unique software control system developed by the authors and others.
A New Method for Overconstraint Analysis Based on Kinematic Compatibility of Single-Opened-Chains
Authors: Jin Qiong , Hang Lu-Bin , Yang Ting-Li
Published: December 2020

A new method for analyzing overconstrained mechanisms is presented in this paper according to the kinematic compatibility criterion of single-opened-chains (SOCs). This criterion states that: if for any value of an active input, two SOCs have die same distances and angles between two ending axes of each SOC, and the difference of axis-lengths corresponding to each hand-side for two SOCs is kept constant, then the two SOCs can be combined together as one closure loop which is an overconstrained mechanism. This method is simple with four clear targets. It is quite different from other methods because the input-output relationships of variables can be obtained during overconstraint analysis. In order to find overconstrained mechanisms, we can begin with parts of compatibility conditions to obtain some kinematic relationships, so that the input-output law and the overconstraint conditions satisfying all compatibility relationships could be given. As examples, the 4R overconstrained mechanisms and a 4R2P overconstrained mechanism are proved using this method.
Assembly Configurations of Spatial Single-Loop Single-DOF Mechanisms With at Least One Spheric or Planar Joint
Authors: Foster David E. , Cipra Raymond J.
Published: December 2020

This paper examines the problem of finding the assembly configurations, also called circuits, of spatial single-loop single-DOF mechanisms with spheric and planar joints. All six lower pairs are considered: revolute (R), cylindric (C), prismatic (P), helical (H), spheric (S), and planar (E). The RSSR, CSS, CCS, RRSC, RSRC, and RRSRR mechanisms are covered, along with all variations in which an R joint is replaced with a P or H joint, or an S joint is replaced with an E joint. A numerical method is given to find the ACs, and is illustrated with several examples.
Analytic Geometric Design of Spatial R-R Robot Manipulators
Authors: Mavroidis Constantinos , Alam Munshi , Lee Eric
Published: December 2020

This paper studies the geometric design of spatial two degrees of freedom, open loop robot manipulators with revolute joints that perform tasks, which require the positioning of the end-effector in three spatial locations. This research is important in situations where a robotic manipulator or mechanism with a small number of joint degrees of freedom is designed to perform higher degree of freedom end-effector tasks. The loop-closure geometric equations provide eighteen design equations in eighteen unknowns. Polynomial Elimination techniques are used to solve these equations and obtain the manipulator Denavit and Hartenberg parameters. A sixth order polynomial is obtained in one of the design parameters. Only two of the six roots of the polynomial are real and they correspond to two different robot manipulators that can reach the desired end-effector poses.
A Comparative Study on Some Different Methods for Complete Balancing of Shaking Force and Moment of Linkages Using Force Counterweights and Inertia Counterweights
Authors: Yang Ting-Li , Zhang Ming , Xu Zhen
Published: December 2020

A systematical comparative study of some methods for complete force and moment balance is presented in this paper, such as, the linearly independent vectors method, the mass-moment substitution method, the complex mass substitution method and a numerical method by a few kinematic positions for force balance; the quasi-linearly independent vectors method and the momentum-moment substitution method for complete moment balance. Their fundamental principles and characteristics are described and their relative merits and some limitations are discussed. This comparative study shows:

(1) for complete force balance, the linearly independent vectors method and the mass-moment substitution method are two systematical methods. Relatively, the latter has two merits: i) according to the derived formula, the force balance conditions can be written down directly instead of extracting them from kinematic equations of a linkage, and derivation of the formula is rather simple; ii) there need not to introduce the complex masses and to determine their loci.

(2) for complete moment balance, the momentum-moment substitution method is a systematical theory and there are two merits: i) according to the derived formula, the moment balance conditions can be written down directly instead of extracting them from kinematic equations of the linkage; ii) the basic idea of this method is the same as of the mass-moment substitution method. Perhaps, the mass-moment and momentum-moment substitution method is a systematical and practical theory for complete force and moment balance of planar and spatial linkages.
On the Development of Reactionless Parallel Manipulators
Authors: Ricard Rémi , Gosselin Clément M.
Published: December 2020

This article presents a method for the complete dynamic balancing of 3-dof planar parallel manipulators. The method is based on the use of special legs constructed with modules based on dynamically balanced four-bar linkages. First, different families of dynamically balanced four-bar linkages are established. Then, examples of the different families of four-bar linkages are given as well as examples of 3-dof planar reactionless parallel manipulators.
A Novel Three-DOF Translational Platform Mechanism and its Kinematics
Authors: Zhao Tie Shi , Huang Zhen
Published: December 2020

To enrich the type of three-DOF parallel mechanisms, a novel 3-RRC platform mechanism model is presented in this paper. The upper platform of this 3-DOF parallel manipulator can realize three-dimension translations without any rotations. The solutions are developed for both the inverse and forward kinematics. The inverse position kinematics produces two solutions for each limb of manipulator. The forward position kinematics is reduced to an eighth-degree polynomial equation. The velocity and acceleration analyses are also given. Some numerical examples and relational curves are presented finally.
A Geometric Algorithm for the Computation of the Constant-Orientation Workspace of 6-RUS Parallel Manipulators
Authors: Bonev Ilian A. , Gosselin Clément M.
Published: December 2020

This paper presents a geometric algorithm for the computation of the constant-orientation workspace of 6-RUS parallel manipulators. While the basic philosophy of this algorithm is not new, the proposed computational process involving surface intersections is original and is the major contribution of the paper. Particularly, an analytic description of the points that constitute the edges of the constant-orientation workspace is presented. The latter is done through a new algorithm for the computation of the intersection points between a general torus and a circle.
Closed-Form Forward Dynamic Equations of 6-DOF

P

US Type Parallel Manipulators
Authors: Kim Jong-Phil , Ryu Jeha
Published: December 2020

This paper presents closed-form forward dynamic equations of six degree-of-freedom HexaSlide type parallel manipulators. The HexaSlide type parallel manipulators are characterized by an architecture with constant-length links that are attached to moving sliders on the ground and to a mobile platform. Based on the kinematic analysis, forward dynamic equations of motion of the parallel manipulator are derived by the Newton-Euler approach. In this derivation, joint frictions as well as all link inertia are included. The correctness of derived dynamic equations is validated by a commercial dynamic simulation software. The kinematic and dynamic equations may be used in the computer simulation of various control strategies.
Force Coordination of a Discretely Actuated Parallel Array
Authors: Yang Po-hua , Waldron Kenneth J.
Published: December 2020

An array of two-state actuators, i.e. a bundle of binary actuators acting in parallel, can be regarded as a simplified model of biological muscle. The subject of this paper is to investigate the properties of a wrench generator system which is composed of a bundle of pneumatic cylinders connected between an output member and base. Each actuator is postulated to operate in a discrete manner. The parallel array is viewed as a programmable force generator, rather than as a motion generator. The force control problem of this kind of system is not straightforward, since it requires a boolean solution. In this paper, we will propose and explore three possible methods for controlling the force generation of a discretely actuated parallel array.
A Linear Displacement Bistable Micromechanism
Authors: Baker Michael S. , Lyon Scott M. , Howell Larry L.
Published: December 2020

Bistable mechanisms have proven their importance at both the macro and micro level in switches, valves and positioners. This paper examines the application of compliant functionally binary pinned-pinned segments in linear motion bistable mechanisms. The equations which govern the force-deflection characteristics of a circular-arc pinned-pinned segment are developed and then applied to create a linear displacement bistable mechanism. The results are then applied to a specific bistable micromechanism configuration that was fabricated and successfully tested.
Study of Kinemtically Singular Configurations for the Seven Degree-of-Freedom Anthropomorphic Arm
Authors: Cheng Li-Ping , Kazerounian Kazem
Published: December 2020

In this paper, a seven degree-of-freedom anthropomorphic arm model defined by zero-position notation is used to study the kinematically singular configurations of human arm. The three findings of this study are: (1) A relationship is shown between the rank of Jacobian matrix J and the number of corresponding reciprocal screws for singular configurations of any three dimensional manipulator arm. (2) By investigating the geometrical positions of this model, its various singular configurations are identified and illustrated. (3) The determinant and cofactor matrix of JJT, and the sub-determinants of J are also examined to help a better understanding of the singularity conditions and characteristics for the seven degree-of-freedom anthropomorphic arm.
A Spatial Mechanism With Higher Pairs for Modelling the Human Knee Joint
Authors: Di Gregorio Raffaele , Parenti-Castelli Vincenzo
Published: December 2020

By generalizing a previous model proposed in the literature, a new spatial kinematic model of the knee joint passive motion is presented. The model is based on an equivalent spatial parallel mechanism which relies upon the assumption that fibres within the anterior cruciate ligament (ACL), the medial collateral ligament (MCL) and the posterior cruciate ligament (PCL) can be considered as isometric during the knee flexion in passive motion (virtually unloaded motion). The articular surfaces of femoral and tibial condyles are modelled as 3-D surfaces of general shapes. In particular, the paper presents the closure equations of the new mechanism both for surfaces represented by means of scalar equations that have the Cartesian coordinates of the points of the surface as variables and for surfaces represented in parametric form. An example of simulation is presented in the case both femoral condyles are modelled as ellipsoidal surfaces and tibial condyles as spherical surfaces. The results of the simulation are compared to those of the previous models and to measurements. The comparison confirms the expectation that a better approximation of the tibiofemoral condyle surfaces leads to a more accurate model of the knee passive motion.
A Polynomial Equation for a Coupler Curve of the Double Butterfly Linkage
Authors: Pennock Gordon R. , Hasan Atif
Published: December 2020

This paper presents a closed-form polynomial equation for the path of a point fixed in the coupler links of the double butterfly linkage. The revolute joint that connects the two coupler links of this planar eight-bar linkage is chosen to be the coupler point. A systematic approach is presented to obtain the coupler curve equation, which expresses the Cartesian coordinates of the coupler point solely as a function of the link dimensions; i.e., the equation is independent of the angular joint displacements of the linkage. From this systematic approach, the polynomial describing the coupler curve is shown to be, at most, forty-eighth order. This result is believed to be an original contribution to the literature on coupler curves of a planar eight-bar linkage.
Surface Fatigue Lives of Case-Carburized Gears With an Improved Surface Finish
Authors: Krantz T. L. , Alanou M. P. , Evans H. P. , Snidle R. W.
Published: December 2020

Previous research provides qualitative evidence that an improved surface finish can increase the surface fatigue lives of gears. To quantify the influence of surface roughness on life, a set of AISI 9310 steel gears was provided with a near-mirror finish by superfinishing. The effects of the superfinishing on the quality of the gear tooth surfaces were determined using data from metrology, profilometry, and interferometric microscope inspections. The superfinishing reduced the roughness average by about a factor of 5. The superfinished gears were subjected to surface fatigue testing at 1.71-GPa (248-ksi) Hertz contact stress, and the data were compared with the NASA Glenn gear fatigue data base. The lives of gears with superfinished teeth were about four times greater compared with the lives of gears with ground teeth but with otherwise similar quality.
Effect of Gear-Side Case-Hardening on Residual Stresses of Case-Hardened Gears
Authors: Miyachika Kouitsu , Oda Satoshi , Fujio Hiroshige
Published: December 2020

This paper presents a study on effects of the case depth, the case-hardened part, the face width, the rim thickness and the standard pressure angle on residual stresses of case-hardened gears. A heat conduction analysis and an elastic-plastic stress analysis for the case-hardening process of spur gears were carried out by the three-dimensional finite-element method (3D-FEM), and then residual stresses were obtained. It was found that the compressive residual stress σ*θ = 30° at Hofer’s critical section of the end of the face width is smaller in magnitude than that of the middle of the face width, and that the absolute value of σ*θ = 30° of the middle of the face width decreases owing to case-hardening the gear-side and the decreasing rate increases with an increasing case depth and a decreasing face width.
Finite Element Modelling and Analysis for Involute Worm Gears With Localised Tooth Contact
Authors: Su D. , Yang F. , Gentle C. R.
Published: December 2020

A general approach is reported in this paper for finite element modelling and analysis of involute worm gear with localised tooth contact. The process of finite element modelling is based on the modified tooth geometry which was presented in a previous paper. The finite element analyses were conducted using commercially available software. The following topics have been investigated in this study: (1) geometric modelling method for involute worm gears, (2) tooth elastic deformation and tooth root stress of worm gear under different loads, and (3) instantaneous tooth meshing stiffness and loaded transmission error of the involute worm gear. Although this study is aimed at involute worm gears, the method developed is applicable for other worm gear types.
Metal Belt CVT’s: Performance Parameters
Authors: Browne Vance D.
Published: December 2020

Automotive applications of CVT’s using metal belts are continuing to grow. There has been a significant amount of work in the detailed mechanics for these CVT’s.

This CVT technology may be extended into non-automotive areas, which have different size, torque, ratio and speed requirements than automotive applications. The purpose of this paper is to explore the basic performance parameters for the metal belt CVT outside the automotive envelope and to present a design procedure for an initial estimate of torque capacity. This may then be used for preliminary functional feasibility evaluation of metal belt CVT’s in various applications. It can also serve as an instructional tool in mechanical engineering design courses.

The governing equations are first presented for the simplified analysis. Also an optimum pitch radius is derived to maximize torque capacity. A design procedure is listed. This is first applied to a baseline automotive type configuration CVT to illustrate the procedure. Next, the procedure is applied to a non-automotive CVT that could be a diesel engine vehicle or industrial drive characterized by lower engine speeds, higher torque, larger ratio range and greater space available for the transmission.

For the non-automotive application it is shown that optimization for maximum torque capacity vs minimum size for a given belt design can significantly increase torque capacity at overdrive in the range of 25%. The amount of increase depends on the engine speed and an increase in sheave diameters is required.