AER201 - Engineering Design

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HIL - Hardware in the Loop Simulation Room

An imperative mission in any Engineering Design course is to provide the students with the means of analyzing their design ideas before and during the implementation phase. It is thus essential to teach them how to gain insight into their systems by using simulation tools before significant time and costs are invested. The message to be delivered is that simulation technology can cut costs, minimize risks, improve reliability, and bring a system into operation more quickly. A wide variety of simulation tools have been applied to systems design, most of which focus on analytical issues. However, two important aspects of the recent advanced simulation techniques are highly recommended for a basic design course, such as AER201Y, which are below:


Hardware in the Loop:

While classical simulations merely involve mathematical model of the system to be analyzed, advanced simulation tools incorporate direct links to the developed or to-be-developed hardware, and overall form integrated rapid-prototyping systems. The key feature of rapid-prototyping systems is fast transfer of slow-motion off-line simulation, running on a PC or workstation, to a real-time simulation running on a dedicated processor linked to the physical hardware components. From energy production, to aerospace and aeronautics, to robotics, automotive, naval, and defense, real-time simulation and support for hardware-in-the-loop modeling are increasingly recognized as essential tools for a design.

Object-Oriented Multidisciplinary Modeling:

Recent advances in modern technology led to the advent and popularity of cross-disciplinary engineered products, namely mechatronic systems. Mechatronic systems are inherently complex due to the presence of not only mechanical and electronic components but also built-in informational elements that are intensively coupled in the systems. Hence, mathematical modeling of such systems, in a form of textual coding, requires fundamental multidisciplinary knowledge and expertise that would be far beyond the assigned curriculum of a basic engineering design course. The new approach of object-oriented modeling is an appropriate alternative, through which simulations can be built by combining elements (mechanical, electronic, computer, etc.) from existent libraries of reusable components. This feature makes it possible to model large, complicated systems that combine elements from many different domains without addressing their underline theory.

It is the attempt of this module to introduce students to an object-oriented hardware-in-the-loop (HIL) simulation station that would allow them to investigate all aspects of a rapid-prototype environment, thereby assisting them in their design and implementation of their design projects.


There are two types of simulation stations available for students taking AER201Y. There is one high end HIL station located in SF4003 that consists of one host Pentium III 1GHz computer and two Pentium 200 MHz targets. Within each target is a PCIM-DAS1602/16 analog and digital I/O board used for data acquisition from the physical components of the system. The board itself has two DB-37 connectors, one for analog I/O and the other for digital. The connectors are joined to a panel for student use. The host machine runs the Windows NT platform and has two core software components. The first is MATLAB computational software containing the Simulink , Real-Time Workshop, and xPC Target toolboxes. The other is Dymola modeling software, the primary utility the students will use to simulate their systems. A graphical interface between Dymola and Simulink is available so that Dymola models can be compiled and downloaded to the target using the MATLAB toolboxes. The host is connected to the target using the TCP/IP protocol across the local area network (LAN). By this connection, the host is able to download applications to the target as well as monitor signals through xPC target scopes. Numerical data from the real-time kernel can also be accessed by using the Data Archiving utility within the Real-Time Workshop toolbox. The high-end station is a complete hardware in the loop station that will allow students to simulate their systems entirely in code and then gradually replace modules with actual physical components.

The lower end station consists of one Pentium 100 host and one 486DX target. There are twenty-four of these stations located in SF4012 and are available for students during their regular lab period. The setup of these stations is similar to that of the high end station in terms of software but have notable hardware differences. First, the host machines use two communication (COM) ports, one DB9 connection set as COM1 and one DB25 connection set as COM2. On most hosts, the DB9 connection is used for the mouse while the other is used for communication to the target machine. Unlike the high-end HIL machines, the lower end station uses RS-232 serial port communication between host and target. The host can perform the same operations on the target but at a reduced speed due to the baud rate limits of serial communication. The target machine has two COM ports as well. Both COM ports use DB9 male ports of which COM1 is used for communication to the host and COM2 is used for interfacing to an external device with a serial port. For most AER201 S projects, this external device will be a microcontroller with a built-in USART (universal synchronous asynchronous receiver transmitter) such as the Microchip PIC16F877/16. Unlike the high-end targets, these target machines do not have an I/O board installed and will not be used for data acquisition in the same manner as the high-end targets. The lower-end stations will be used for real-time testing and debugging of the microcontroller while simulating the physical components on the target machine through code. 8.3 SOFTWARE

There are four major software programs used by AER201S students. They are MATLAB computational software with the Simulink , Real-Time Workshop, and xPC Target toolboxes, Dymola modeling software, MPLAB Integrated Development Environment (IDE), and Microsoft Visual C++ 6.0. In terms of of using the HIL stations however only MATLAB, its toolboxes, Dymola , and VC++, are required. MPLAB, on the other hand, is a MS Windows based graphical user interface (GUI) used exclusively for programming and debugging Microchip microcontrollers, e.g. PIC16F877/16, and thus is only applicable to students using such microcontrollers.