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A Decision Based Mobility Model for Semi and Fully Autonomous Vehicles

FCA US LLC-Christopher Slon
Oakland University-Vijitashwa Pandey, Line Deschenes
  • Technical Paper
  • 2020-01-0747
To be published on 2020-04-14 by SAE International in United States
With the emergence of intelligent ground vehicles, an objective evaluation of vehicle mobility has become an even more challenging task. Vehicle mobility refers to the ability of a ground vehicle to traverse from one point to another, preferably in an optimal way. Numerous techniques exist for evaluating the mobility of vehicles on paved roads, both quantitatively and qualitatively, however, capabilities to evaluate their off-road performance remains limited. Whereas a vehicle’s off-road mobility may be significantly enhanced with intelligence, it also introduces many new variables into the decision making process that must be considered. In this paper, we present a decision analytic framework to accomplish this task. In our approach, a vehicle’s mobility is modeled using an operator’s preferences over multiple mobility attributes of concern. We also provide a method to analyze various operating scenarios including the ability to mitigate uncertainty in the vehicles inputs. An example of this is the collection of soil properties data using techniques such as remote sensing. Operators of these vehicles are interested in finding the value of collecting such information.…
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Assessing Fit and Finish Design Sensitivity By Mapping Measurements to VNM Utility

FCA US LLC-Christopher Slon, Xiaona LI, Vita Valetchikov
Oakland University-Vijitashwa Pandey
  • Technical Paper
  • 2020-01-0600
To be published on 2020-04-14 by SAE International in United States
In the automotive industry “fit and finish” is the term applied to the perceived quality of the alignment of one part to another. Fit and finish gives the buyer a sense of the overall quality of the vehicle purely from an aesthetic perspective. Fit and finish is usually evaluated by the manufacturer through dimensional measurements of the “gap” and “flush” conditions between panels. Since variation in the measurements increases the probability that a vehicle will result in poor fit and finish, relatively arbitrary limits are put on these measurements to define whether a gap or flush condition is acceptable or not. It is suspected that the relationship between the appropriate measurement limits and the customer’s perception of quality is highly influenced by the design of the interface between panels. This paper proposes a method to evaluate the sensitivity of the perceived quality of the designed interface to variation in the measurements of gap and flush. The novelty is in the application of the concept of von Neumann-Morgestern utility to fit and finish. The significance is…
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Reconciling Simultaneous Evolution of Ground Vehicle Capabilities and Operator Preferences

FCA US LLC-Christopher Slon
Oakland University-Vijitashwa Pandey
  • Technical Paper
  • 2020-01-0172
To be published on 2020-04-14 by SAE International in United States
An objective evaluation of ground vehicle performance is a challenging task. This is further exacerbated by the increasing level of autonomy, dynamically changing the roles and capabilities of these vehicles. In the context of decision making involving these vehicles, as the capabilities of the vehicles improve, there is a concurrent change in the preferences of the decision makers operating the vehicles that must be accounted for. Decision based methods are a natural choice when multiple conflicting attributes are present, however, most of the literature focuses on static preferences. In this paper, we provide a sequential Bayesian framework to accommodate time varying preferences. The utility function is considered a stochastic function with the shape parameters themselves being random variables. In the proposed approach, initially the shape parameters model either uncertain preferences or variation in the preferences because of the presence of multiple decision makers. We consider this utility distribution as the prior and update it to a posterior with feedback acquired from actual system use. The framework improves the utility function and thereby the decisions made…
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Balancing Lifecycle Sustainment Cost with Value of Information during Design Phase

CCDC Ground Vehicle Systems Center-Sam Kassoumeh, Monica Majcher, James Ealy, David Gorsich, Paramsothy Jayakumar
Oakland University-Vijitashwa Pandey
  • Technical Paper
  • 2020-01-0176
To be published on 2020-04-14 by SAE International in United States
The complete lifecycle of complex systems, such as ground vehicles, consists of multiple phases including design, manufacturing, operation and sustainment (O&S) and finally disposal. For many systems, the majority of the lifecycle costs are incurred during the operation and sustainment phase, specifically in the form of uncertain maintenance costs. Testing and analysis during the design phase, including reliability and supportability analysis, can have a major influence on costs during the O&S phase. However, the cost of the analysis itself must be reconciled with the expected benefits of the reduction in uncertainty. In this paper, we quantify the value of performing the tests and analyses in the design phase by treating it as imperfect information obtained to better estimate uncertain maintenance costs. A multi-attribute decision framework for military ground vehicles acquisition is employed to illustrate the methodology and the value of performing the analysis early in the system's lifecycle. Attributes considered are maintenance cost and operational availability, while the utility is calculated for a risk averse decision maker. Numerical methods are employed to calculate the value…
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An Optimization Framework for Fixture Layout Design for Nonrigid Parts: An Automotive Perspective

SAE International Journal of Materials and Manufacturing

Oakland University, USA-Christopher Slon, Vijitashwa Pandey
  • Journal Article
  • 05-13-01-0001
Published 2019-11-19 by SAE International in United States
The inspection process of non-rigid parts during manufacturing and assembly is inherently challenging. This is exacerbated by the need for accurate real-time part data in the digital age. Although many ad hoc techniques exist, there are no rigorous methods to evaluate the quality of a fixture layout before final parts and gauges are available. This typically happens so late in the manufacturing process that errors found can scarcely be remedied. Additionally, the modifications to the gauge are usually costly and can result in significant delays, when performed this late in the process. This article proposes an optimization-driven mathematical approach tailored toward non-rigid parts to identify the best locator layout, early in the part design phase. A metric is proposed using robotic grasping theory to quantify the quality of the locating scheme and serves as the objective of optimization. The proposed method is implemented using a tolerancing software that performs finite element analysis (FEA) on the parts to predict its state given the force and torque inputs, including the effect of gravity. An evolutionary algorithm is…
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Mixture Distributions in Autonomous Decision-Making for Industry 4.0

SAE International Journal of Materials and Manufacturing

Oakland University, USA-Christopher Slon, Vijitashwa Pandey, Sam Kassoumeh
  • Journal Article
  • 05-12-02-0011
Published 2019-05-29 by SAE International in United States
Industry 4.0 is expected to revolutionize product development and, in particular, manufacturing systems. Cyber-physical production systems and digital twins of the product and process already provide the means to predict possible future states of the final product, given the current production parameters. With the advent of further data integration coupled with the need for autonomous decision-making, methods are needed to make decisions in real time and in an environment of uncertainty in both the possible outcomes and in the stakeholders’ preferences over them. This article proposes a method of autonomous decision-making in data-intensive environments, such as a cyber-physical assembly system. Theoretical results in group decision-making and utility maximization using mixture distributions are presented. This allows us to perform calculations on expected utility accurately and efficiently through closed-form expressions, which are also provided. The practical value of the method is illustrated with a door assembly example and compared to traditional random assembly methods and results.
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A Decision Analytic Approach to Incorporating Value of Information in Autonomous Systems

Oakland University-Sam Kassoumeh, Vijitashwa Pandey
Published 2018-04-03 by SAE International in United States
Selecting the right transportation platform is challenging, whether it is at a personal level or at an organizational level. In settings where predominantly the functional aspects rule the decision making process, defining the mobility of a vehicle is critical for comparing different offerings and making acquisition decisions. With the advent of intelligent vehicles, exhibiting partial to full autonomy, this challenge is exacerbated. The same vehicle may traverse independently and with greater tolerance for acceleration than human occupied vehicles, while, at the same time struggle with obstacle avoidance. The problem presents itself at the individual vehicle sensing level and also at the vehicle/fleet level. At the sensing and information level, one can be looking at issues of latency, bandwidth and optimal information fusion from multiple sources including privileged sensing. At the overall vehicle level, one focuses more on the ability to complete missions. Clearly, decisions at the sensing level impact vehicle level decisions and a common paradigm for both is not only possible, but also desirable. In this paper, we use a decision theoretic model of…
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Reliability and Resiliency Definitions for Smart Microgrids Based on Utility Theory

Oakland University-Vijitashwa Pandey, Kevin Weinert, Zissimos Mourelatos
US Army RDECOM-David Gorsich
Published 2017-03-28 by SAE International in United States
Reliability and resiliency (R&R) definitions differ depending on the system under consideration. Generally, each engineering sector defines relevant R&R metrics pertinent to their system. While this can impede cross-disciplinary engineering projects as well as research, it is a necessary strategy to capture all the relevant system characteristics. This paper highlights the difficulties associated with defining performance of such systems while using smart microgrids as an example. Further, it develops metrics and definitions that are useful in assessing their performance, based on utility theory. A microgrid must not only anticipate load conditions but also tolerate partial failures and remain optimally operating. Many of these failures happen infrequently but unexpectedly and therefore are hard to plan for. We discuss real life failure scenarios and show how the proposed definitions and metrics are beneficial.
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Decision-Based Universal Design - Using Copulas to Model Disability

Oakland Univ.-Vijitashwa Pandey, Megan Conrad
Published 2015-04-14 by SAE International in United States
This paper develops a design paradigm for universal products. Universal design is term used for designing products and systems that are equally accessible to and usable by people with and without disabilities. Two common challenges for research in this area are that (1) There is a continuum of disabilities making it hard to optimize product features, and (2) There is no effective benchmark for evaluating such products. To exacerbate these issues, data regarding customer disabilities and their preferences is hard to come by. We propose a copula-based approach for modeling market coverage of a portfolio of universal products. The multiattribute preference of customers to purchase a product is modeled as Frank's Archimedean Copula. The inputs from various disparate sources can be collected and incorporated into a decision system. Thereafter, an optimal portfolio is found through optimization which takes into account the disability level continuum while accounting for overlap demand within the product family. We present a case study to demonstrate our approach and present results of various sensitivity analyses.
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Enhancing Decision Topology Assessment in Engineering Design

SAE International Journal of Materials and Manufacturing

Oakland Univ.-Vijitashwa Pandey, Zissimos Mourelatos
US Army TARDEC-Matthew Castanier
  • Journal Article
  • 2014-01-0719
Published 2014-04-01 by SAE International in United States
Implications of decision analysis (DA) on engineering design are important and well-documented. However, widespread adoption has not occurred. To that end, the authors recently proposed decision topologies (DT) as a visual method for representing decision situations and proved that they are entirely consistent with normative decision analysis. This paper addresses the practical issue of assessing the DTs of a designer using their responses. As in classical DA, this step is critical to encoding the DA's preferences so that further analysis and mathematical optimization can be performed on the correct set of preferences. We show how multi-attribute DTs can be directly assessed from DM responses. Furthermore, we show that preferences under uncertainty can be trivially incorporated and that topologies can be constructed using single attribute topologies similarly to multi-linear functions in utility analysis. This incremental construction simplifies the process of topology construction. The methods are demonstrated using a design decision making problem of a welded beam.
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