18CSE483T - INTELLIGENT MACHINING UNIT 2 & 3 - 12M

 12M:


Open architectures

Open architecture for machining process:

  • Based on open standards

  • Easy to modify and to exchange data between different types of software application

  • Supported by a large community of developers

  • Eg: combination of TCP/IP and HTTP


Machine tool open system architecture for intelligent control (MOSAIC):

  • Developed at New York University

  • To support information flow required task

  • Based on memory mapped backplane architecture (VME)

  • Is an agent-based machining system architecture

  • Is a hardware running on POSIX OS

  • Principles: 

  • Open architecture

  • Common OS at all levels of machines

  • Standardized object oriented knowledge exchange


Next Generation Machine/ Workstation Controller (NGC):

  • Was initiated by the US government for restructuring machine tool industry by enabling Hardware, software, process control technologies

  • NGC provides interface for scalability and third party product development

  • Software interface built based on [NML] Neutral Manufacturing Knowledge process control

  • Requirements addressed by NGC:

  • Hardware, software architecture

  • Network capabilities

  • Task planning

  • Process control

  • Fault management

  • Sensor interface


Manufacturing Automation Protocol (MAP):

  • Was developed by general Motors to meet its manufacturing integration needs

  • Supports application layer protocols

  • Uses the ISO reference model

  • FTAM - File Transfer and Access Method

  • CLNS - Connector Less Network

  • ESIS - End System Intermediate System

  • ACSE - Association Control Service Element

  • MMS - Manufacturing Message Specification


Open Systems Architecture for Control within Automation Systems (OSACA):

  • European initiative to define a vendor-neutral, open controller architecture

  • OSACA’s approach is to develop an API for control applications and an appropriate infrastructure to achieve interoperability, scalability and reusability of applications

  • Three main areas:

  • Communication system: to define a hardware and system software independent interface to exchange information between different application modules of a controller

  • Reference architecture: to determine the functional units of a controller such as Motion Control and Logic Control and specifies the external interfaces of them

  • Configuration system: to enable dynamic configuration of a controller by combining different application modules at boot-up time


Explain in detail the different methodologies for transforming data to information

  • Data acquisition is the process of sampling signals and converting the resulting samples into digital numeric values that can be manipulated by a computer

  • The analog-to-digital conversion (ADC) process converst the input continuous physical quantity from a sensor to a digital number that represents the quantity’s amplitude

  • Techniques: 

  • Time domain analysis

  • Frequency domain analysis

  • Time-frequency domain analysis


Time domain analysis:

  • Format with the vertical axis as amplitude or voltage and the horizontal axis as time

  • This method analyzes a sequence of data points, measured typically at successive time instants with uniform time intervals, in order to extract meaningful statistics and other characteristics of the data

  • 3 main time series analysis techniques:

  • Autoregressive (AR)

  • Moving average (MA)

  • Autoregressive-moving average (ARMA)


Frequency domain analysis:

  • It can provide information with regard to signal components in certain frequency range and is regarded as the most useful method for signal processing

  • In many machining operations with a rotating spindle, the frequency spectrum of measured signals, such as vibration or cutting forces, carries a great deal of information that can be used to monitor and diagnose the process and tool condition

  • An inverse DFT can transform the resultant frequency spectrum back into the time domain


Time-frequency domain analysis:

  • Although FFT based methods are widely used, one main limitation is for the methods is that they are not suitable for nonstationary signals

  • A nonstationary signal means that its frequency changes over time

  • FFT is unable to detect the frequency changes

  • To address this issue, a number of time-frequency domain analysis techniques have been developed, including

  • Short-time fourier transform (STFT)

  • Wigner-Ville distribution

  • Wavelet transform


Explain in detail about techniques of knowledge representation in AI

Knowledge representation:

  • Describes the representation of knowledge

  • It is a study of how the beliefs, intentions and judgements of an intelligent agent can be expressed suitably for automated reasoning

Techniques of knowledge representation in AI:

Logical representation:

  • Represents conclusion based on various conditions

  • Each sentence translated to logic using syntax and semantics

  • Syntax - determine which symbol use in KR

  • Semantics - rules to interpret sentence in logic; assign meaning to sentence

  • Advantage: helps to perform logic reasoning

  • Disadvantage: may not be very natural, have some restrictions and are challenging to work with


Semantic network representation:

  • Representation in the form of graphical network

  • Objects as nodes and arcs to give relation between objects

  • Consists of 2 types of relations:

  • IS-A relation

  • Kind-of relation

  • Advantage: simple and easy to understand

  • Disadvantage: take more computational time at runtime


Frame representation:

  • A frame is a record like structure that consists of a collection of attributes and values to describe an entity in the world

  • Basically it consists of a collection of slots and slot values of any type and size

  • Slots have names and values which are called facets

  • Advantage: easy to understand, visualize and add slots 

  • Disadvantage: inference mechanism cannot be smoothly proceeded


Production rules:

  • In production rules, agent checks for the condition and if the condition exists the production rules fires and corresponding action is carried out

  • The system consists of 3 main parts:

  • Set of production rules

  • Working memory

  • Recognize act cycle

  • Advantage: highly modular and can be easily removed or modified

  • Disadvantage: does not exhibit any learning capabilities and is inefficient


Discuss in detail about tools and techniques for conceptual design

Conceptual design is the part of the design process where

  • By identifying the essential problems, searching for appropriate working principles and combining these into a working structure

  • The basic solution path is laid down through the elaboration of a solution principle

  • conceptual design specifies the principle solution

AI and design:

  • AI is concerned with the application of knowledge

  • Within AI, 3 main directions of reasoning

  • Reasoning by logic

  • Reasoning by learning

  • Reasoning by analogy

Reasoning by logic:

  • Expert systems apple rule-based reasoning (RBR) technique, a form of reasoning by logic

  • An expert system is useful when the domain knowledge can be formalized into simple rules and when common sense does not play an important role

Reasoning by learning:

  • Reasoning by learning can be implemented with artificial neural networks

  • An ANN consists of nodes connected vis adjustable weights

Reasoning by analogy:

  • The third form of reasoning, reasoning by analogy, is best exemplified by Case-Based Reasoning (CBR)

  • Cases are stored in a case-base to create a reservoir of problem-solution combinations

AIDA system:

  • AI- supported design of Aircraft

  • Built of three modules and a central interface

  • Case-based reasoning module

  • Functional module

  • Geometrical module

  • Central user interface

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