Problem with SimEvents regarding the simulation of a inverted Pendulum with round robin network

Question

Wouter 2014-2-27

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/119339-problem-with-simevents-regarding-the-simulation-of-a-inverted-pendulum-with-round-robin-network

编辑： Wouter 2014-2-27

I have a simulink model of a inverted pendulum. Now I want to simulate this with a wireless network with a round-robin network. The inverted pendulum has two sensors, for the cart position and angle of the pendulum. Now in practice this means that at a certain time t,

Cart position is send
Controller computes control effort based on the new cart position and a previous pendulum angle
Pendulum angle is send
Controller computes control effort based on the new pendulum angle and a previous cart position
Etc.

Now I use the SimEvents toolbox to Simulate the network. The problem I am facing is in a Matlab function I created which is a internal memory so to speak for the previous pendulum angle/cart position. This code is placed at the end of the network, see image, and its output is directed to the controller.

The function looks like as follows:

function y = fcn(message,type)
%#codegen
persistent mem;
if isempty(mem)
    mem = [0; 0];
end
mem(type) = message;
y = mem;

The problem is in the fact that it appears to be that the getAttribute Simulink block does not return a type of the message (type = 1 for cart position, type = 2 for pendulum angle), which I initialize when I create the corresponding entity. The Matlab function does then generate a error since of course it cannot set a index 0.

I hope somebody can help me with this problem.

The files: Initialization file: https://dl.dropboxusercontent.com/u/20782274/init.m Main file: https://dl.dropboxusercontent.com/u/20782274/main.m Control design: https://dl.dropboxusercontent.com/u/20782274/controlDesign.m Simulink file: https://dl.dropboxusercontent.com/u/20782274/invertedPendulum.slx

Download the 4, then run the main file and afterwards the Simulink file.

ps. I have based my code on the examples: http://www.mathworks.nl/help/simevents/examples/comparing-routing-policies.html?prodcode=SE&language=en , http://www.mathworks.nl/help/simevents/examples/effects-of-communication-delays-on-a-flight-control-system.html?prodcode=SE&language=en