Causal Block Diagram assignment

General Information

• UPDATE: The due date is Tursday 9 October 2002, before 23:55.
  
  
• Submissions must be done via WebCT. Beware that WebCT's clock may differ slightly from yours. As described on the Assignments page, all results must be uploaded to WebCT and accessible from links in the index.html file. There is no need to upload AToM³.
  
  
• The assignment must be made in teams of two people. It is understood that all partners will understand the complete assignment (and will be able to answer questions about it).
  
  
• Grading will be done based on correctness and completeness of the solution. Do not forget to document your requirements, assumptions, design, implementation and modelling and simulation results in detail !
  
  
• Extensions, if given, will involve extending not only the alotted time, but also the assignment.
  
  

The assignment

1. You will use the meta-modelling environment AToM³ AToM3-2.2.tgz to implement a Discrete-Time Causal Block Diagram simulator.
   All relevant files are found in the directory CausalBlockDiagram/. Example models are found in the directory CausalBlockDiagram/models/.
   Implementing the simulator means you will modify the file SIM_startResume.py.
   You may wish to have a look at SIM_pause.py and SIM_reset.py. Actually, if you wish to understand how the plotting works, have a look in the Plotting/ directory. The PlotTest.py is a stand-alone script demonstrating the working of the plotter.
   As a starting point, you MUST read and understand DUMP_model.py. It contains examples of ALL parts of the AToM³ API you'll need.
   The SIM_startResume.py given is the solution to last year's assignment. It will work on models
   circle_CausalBlockDiagram_mdl.py, ballistic_CausalBlockDiagram_mdl.py,
   and lorenz_CausalBlockDiagram_mdl.py. That solution provides a Continuous-Time Causal Block Diagram simulator. Also, there is no SimControl block. Rather, simul_t_init, simul_t_final, simul_delta_t, and so on are given as explicitly as global model attributes.
   
   
2. The simulator must be able to handle Discrete-Time models as well as purely algebraic models as shown in model algebraTest_CausalBlockDiagram_mdl.py. The model is shown in Figure 1
   Figure 1: Algebraic Model CBD
   Note how the time_max is 0.0. Your simulator should calculate a solution at that time only.
   
   
3. The simulator must be able to detect dependency loops. The model loopTest_CausalBlockDiagram_mdl.py depicted in Figure 2 for example contains an algebraic loop. You must isolate the algebraic loop and HighLight the links involved. An example of highlighting is given in DUMP_model.py.
   Figure 2: Model containing Algebraic Loop
   
   
   
4. Above all, the simulator must be able to handle delay blocks. The delayTest_CausalBlockDiagram_mdl.py model depicted in Figure 3 is an example.
   Figure 3: Model with Delay Block
   Note how in this example, the simulation termination condition uses the state variable x rather than time. When x reaches the value 50.0, the simulation should stop.
   
   
5. Unlike last year, you must now keep signal values in the signal attribute (an AToM³ list) of each link node. You can now ignore block attributes such as block_out_value and block_tmp_value.
   
   
6. Note how you must handle all block types except Integrator, Derivative, Time, FileIO.
   
   
7. You must build a model for the "circle test". This is the Ordinary Differential Equation (ODE)
   

   x"=-x, x(0)=0, x¢(0)=1.

   Using integrator blocks, this is shown in Figure 4.
   Figure 4: Circle Test Model
   You must us a discretized version (using only Delay blocks) of the ODE. You must however use a discretization of Derivatives rather than of Integrators.
   
   
8. You must include plots of relevant simulation results in your solution report. The best way to do this is to File/Generate PostScript from model from the AToM3 menu bar. You can then convert this .eps file to a bitmap using for example the display tool on Linux machines.
   
   

Using the AToM³ environment

• MODEL_plotWindow.py contains code which gets called when you click on a Plot icon. It opens a plot window. When pressing "new" in that window, it is possible to add plot items (one variable as a function of another).
  
  
• EXPORT_LaTeX.py constains code which gets called when you press the "to LaTeX" button.
  
  
• EXPORT_Mfile.py contains code which gets called when you press the "M-File" button.
  
  
• SIM_startResume.py contains the startResume(parentApp, model) method which gets called when you press the "Exp Start/Resume" button. Currently it starts a thread which contains a data generator. You have to replace this generator by a Time Slicing simulator which produces data using the model structure and node attributes.
  
  
• SIM_pause.py and contains code which pauses the simulation. It gets called when the "Exp Pause" button is pressed.
  
  
• SIM_reset.py contains code which gets executed when the "Exp Reset" button is pressed.