The Team n n Clara Cardoso Acoustical Engineering

The Team n n Clara Cardoso (Acoustical Engineering) Ian Farmer (Electronic Engineering) Sam Hopper (Electronic Engineering) Julian Seidenberg (Software Engineering) GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 2

Project Goals n n To build an online virtual laboratory for control systems demonstrations with 3 D illustrations of the Simulink models To develop this system as a crossplatform successor to existing tools such as the Matlab VR Toolbox 2. 0 GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 3

Presentation outline n n n n n System Architecture Simulink models System timing and control wrapper Java Client/Server system 3 D VRML illustrations Integration and testing Conclusions Questions Demonstration GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 4

System Architecture n System-Level View n Task breakdown GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 5

Architecture Overview GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 6

Architecture Detail GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 7

Advantages n Platform independence n Scalability & Load Balancing n Redundancy & Recoverability GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 8

Disadvantages n Complexity n n n More complex than a simple single host-tohost network connection More effort to install and configure Performance n Layer of indirection causes slight delay GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 9

Task Breakdown GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 10

Simulink Models n n n Bouncing Ball model Radar Tracking Pendulum F 14 Flight Control Newton’s Cradle GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 11

Bouncing ball model n Simple system n Adapted from Matlab demo model n Expanded to move three-dimensionally GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 12

Radar tracking n Matlab demonstration model n Drop in model n Undocumented Aircraft position + + RADAR filter Estimated position Measurement noise GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 13

Pendulum n Simple pendulum model n n Rotation not translation GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 14

F 14 flight control n n n Matlab demonstration model Models elevator control M-file control of variables Elevator GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 15

F 14 flight control (2) n Adaptation of controller GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 16

Newton’s cradle n n n One pendulum model per sphere Connected via collision modelling blocks Pendulum velocity can be set on collision GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 17

System Timing and Control Wrapper n n Controls the timing of the control system simulation Interfaces the simulation with the server GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 18

System Timing n Data sent from Simulink: n n in fixed-length packets at fixed intervals Display applet requires a regular data stream Therefore the accuracy of the timing is important for a smooth simulation GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 19

Timing Development First timing test n n Used a fixed pause between packets Caused a gradual time lag Second timing test n n Used absolute timing from system clock Sufficient accuracy is achieved GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 20

Development of Control Wrapper n n Implementation of a dataflow delay using an s‑function block Delay block can halt the execution of the simulation at regular intervals GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 21

Final Timing and Control Wrapper n Implemented as a two-block wrapper for a control system model n Datasource: providing the control system’s inputs from the server n Datasink: regulating the execution speed and sending the control system’s outputs to the server GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 22

Java Client/Server System n Technology choices n System topology n n n Matlab/Java Interface Process View (Server) Java Control Applet GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 23

Technology choices n Java 1. 1 n not: n n n PHP Cold. Fusion C/C++ C# Matlab GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 24

Technology choices (2) n IBM Java Classbroker n not: n n n Java RMI XML-RPC SOAP GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 25

Matlab/Java Interface GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 26

Process View GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 27

Java Control Applet GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 28

3 D Worlds n Why? n n n To create illustrations of the control systems To appeal to users Building n Combining and scaling: n n n Created objects Existing objects on the web Modified downloaded objects GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 29

Software Used Software For What? Why? VRML 97 To develop the worlds Free, easy, available plug -in-less browser, already used in VR-Toolbox, many downloadable objects Blaxxun 3 D VRML Viewer Free, plug-in-less, small file size File Converter Converted many different file formats, fast, identification of objects’ parts 3 D Exploration GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 30

Software Used (2) Software For What? Why? Blender Object creation and modification Free, cross-platform many online resources and tutorials Milk. Shape 3 D Object creation and modification Imports and exports many file formats, easy to use and learn GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 31

Bouncing Ball n n Ball inside a box controlled by Simulink Used to learn and become familiar with VRML Grass texture in the ground a textured hemisphere sky Airplane propellers and windmill sails rotate GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 32

Radar World n n n Radar to track an airplane The phantom airplane shows the radar tracking “Normal” airplane shows what the radar should track Radar created in Blender Camera tracking the planes so that the user is able to follow them whilst they fly around in the world. GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 33

F 14 World n n F 14 flying Camera tracking the plane so that the user is able to follow it while flying around in the world. GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 34

Newton’s Cradle n n User to interact with a Newton’s cradle developed in Blender House made from rectangular planes Window is a rectangular plane with its transparency material property set to a low value GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 35

Pendulum n n n A pendulum swinging represented by a pendulum clock Room with old fashioned objects Pendulum needed to function as a different group to the rest of the object modelled using Milk. Shape 3 D GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 36

Integration and Testing n System Integration n Summary of Testing GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 37

System Integration n Control System models 3 D Worlds n n n Control System Models Interface Wrapper n n Incorporating the final model as a sub-system in the interface wrapper Interface Wrapper Server n n Synchronising objects and nodes from the model to the world Ensuring correct positioning and visualisation Using instances of Java objects to connect and transfer data to and from the server Server Client n Finalising networking code in order to let multiple clients connect to multiple servers GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 38

Summary of Testing n Simulation timing and execution test results n n n Performance is dependent on the power of the host computer Increased sample times need more processing power Java client/server system test results n n Works without major failures under most conditions However, re-declaration of variables caused stability problems over extended periods of operation until fixed. GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 39

Summary of Testing n Other areas tested: n n Performance/load testing Fail-over Testing Cross platform compatibility Areas not tested: n n Usability testing Security testing GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 40

Summary n Evaluation n Conclusions n Future Work GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 41

Evaluation GDP: VRC VR-Toolbox 2. 0 Viewpoint Lab. View Download size 141 KB + VRML 5470 KB + VRML 3200 KB + Wavelet compressed file 200 MB Installation necessary No Yes Yes Simultaneous users Thousands Unspecified Thousands 50 Bandwidth requirement Modem LAN Platform independent Yes (Java) No (Windows only) Somewhat (Windows + Macintosh) Somewhat (Windows + Linux) Quality of image Medium Quality High Quality Very High Quality N/A Good N/A Very Good Free £ 1870 Free £ 3345 Accuracy simulation Price of GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 42

Conclusions n n n Platform independence: by the use of a three-tier system and the Java technology Privacy & Security: isolation of Matlab and Java applet clients from each other through the server was achieved. Scalability & Load Balancing: The system continued to run with a load of 3000 simultaneously connected clients. Analysability & Testability: It is relatively simple to create client applicants to analyse and test the system. Maintenance & Flexibility: Good maintainability. Encapsulation in objected-oriented programming ensures the system is flexible. GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 43

Conclusions (2) n n n Stability & Recoverability: The system is resistant to clients crashing. Recovery occurs quickly enough in normal use. Small size & quick download: Average download time of just over a minute for a dial-up user and seven seconds for a broadband user Ease of use: The web pages are intuitive. Performance: Adequate performance on an up-to-date computer. Accuracy: Accurate as possible with today’s technology. GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 44

Conclusions (3) n n The system can be used by clients with a broad range of skill levels n simple n accessible n diverse selection of examples Potential application areas: n virtual teaching laboratories n advertisement on the University web page n worldwide conferences. GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 45

Future Work n n n n n Improving security Improving analysability Improving display smoothness Introducing dynamic data stream buffering Creating an automatic installation system Creating a system that solely uses Matlab and is not reliant on Simulink Increasing the amount of control a user has over Matlab Increasing the amount of information provided on the web pages. Providing cut down versions of the VRML models for slow Internet connections Providing a three-dimensional object library GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 46

Demonstrations GDP: Virtual 3 D Control Systems WWW Demonstrator based on Matlab 47