Zhuming Bi - Computer Aided Design and Manufacturing

Figure 1.14Main types of computer memories (Computer History 2019b).

Computers to an information system are machines to a manufacturing system. Computers serve as the transformers to transfer input data to output data. Peripheral devices serve as the interfaces for computers to input raw data and output processed data in applications. Computers at an early time have limited choices of input and output devices such as punch‐cards and printers. Today, many types of devices can be used as inputs and output devices of computer systems. Figure 1.15shows a classification of computer devices for human machine interfaces. A peripheral device can be a unidirectional input , unidirectional output , or bidirectional input and output device (Wole 2018). It is worth noting that with an increase in the capabilities of computer aided systems, more and more smart devices, such as indoor Global Positioning Systems (GPSs), haptic systems, and 3D printers, can be connected to computer systems directly as input and output devices.

Figure 1.15Types of peripheral devices for inputs and outputs.

A computer aided system runs on computers and consists of a set of functional components at different layers of information, from the layer for hardware interfaces to the layers of operating systems, networking, database, sophisticated computer aided tools, and finally to the system layer of applications. Figure 1.16shows the architecture of a computer aided software system. The functional components in the system are generally encapsulated and used independently. These functional components are classified into four groups: (i) software for hardware operation interacting with computers, printers, plotters, and so on, (ii) system software associated with operating systems and networking, (iii) support software consisting of database systems and CAD software, and (iv) application software as comprehensive computer aided systems.

Figure 1.16Computer aided software system architecture.

The architecture of a computer aided software system is modularized; it allows the developers to customize the selections of functional components and integration of the selected components to meet the design needs at different domains and levels of manufacturing systems. It seems obvious that the capabilities of computer aided systems will be continuously expended due to the rapid development of information systems in computing systems, networking systems, and databases. In the next section, the impact of networking and cloud technologies on computer aided systems is briefly discussed.

As an information system, a computer aided software system needs the capabilities to deal with the variety, complexity, and changes of design needs. Three basic strategies to deal with the variety, complexity, and changes are to (i) modularize system architecture, (ii) make functional components flexible, and (iii) support system integration (Bi and Zhang 2001a,b; Bi et al. 2008). To implement these strategies, functional modules must be interoperated, collaborated, and integrated. Therefore, servers and networking technology play a significant role to advance CATs. A server acts as an agent to accept and perform tasks and to generate the results of a task to requesters. Networking allows a number of the servers working collaboratively to solve a holistic problem, whose solution consists of a set of sub‐solutions that are used to divide subproblems with the given constraints. For example, networking makes the following technologies possible in computer aided application systems.

Parallel computing is a type of computation in which many calculations or the execution of processes are carried out at the same time. Large‐scale design problems should be decomposed into smaller ones, so that the sub‐solutions can be obtained by using a number of computing resources concurrently. Parallel computing may refer to parallel processing by a set of central computing units (CPUs) or graphic processing units (GPUs) in one computer or parallel supercomputers containing hundreds or thousands of processors, networks of workstations, multiple‐processor workstations, and embedded systems (Foster 1995). Computer aided systems, especially CAE systems, need parallel processing capabilities to achieve scalability in solving complex design problems, which may involve multiple physics, transient dynamics, or large‐scale coupled models.

Hardware in the loop ( HIL ) simulation is a type of real‐time simulation for the design of real‐time control systems. In HIL, the machine or physical part of the system is networked with the control model through actuators and sensors. The rest of the system is represented by the mathematic model in the simulation. HIL assists in developing and testing complex real‐time embedded systems while considering the complexity of the real‐world system. HIL simulation shows how a control model responds to realistic virtual stimuli in a real‐time manner and can be used to determine whether the mathematic model for a physical system is valid (MathWorks 2018).

Distributed database is a storage solution where a common processor accesses the data in a distributed system. Data may be stored in multiple networked computers in the same location or can be dispersed over a network of interconnected computers. A system server distributes collections of data across network servers or independent computers over intranets, extranets, or the Internet. Computer aided systems benefit from the distributed databases in increasing the scalability, modularity, reliability, and flexibility of systems (Wikipedia 2019c).

Cloud computing is the delivery of computing services such as data collections, computing, data mining, analytics, storage, servers, and more over the Internet for faster innovation, flexible resources, and economies of scale (Microsoft 2019). Computer aided systems greatly benefit from cloud computing over a number of aspects. Firstly , cloud computing allows single users, freelance designers, and SMEs to participate in the entire design processes of complex products; large and multinational companies can work with several hundred SMEs and individual designers to seek design solutions. Secondly , this helps to reduce an overall cost of the design and development processes. Cloud computing helps to reduce the investment on computer aided systems. Traditionally, commercial software tools are associated with the licensing and training costs as well as the additional cost on maintenance, software and hardware upgrades, IT personnel, power requirements, and rental costs for additional space. Cloud solutions offer an alternative where licensing costs are substituted with a subscription fee and the expenditure is substantially reduced since the resources are shared by users in the cloud. Thirdly , most of the cloud services offer pay‐as‐you‐go options, where one pays only for the used computational resources. Such services reduce the overall cost for both the provider and the client since the service loads are customized to the needs (Harish 2018).