How to Output Updated Parameters Value in ode Integration Process When the odeEvent is triggered ?

I was working on multi-body systems collision simulation utilize ode MATLAB function and odeEvent function.

The impact between two body was built as a event using odeEvent MATLAB function.

The impact event will change some parameters which are incorporated in the governing equations of motion such as ydot=f(t,y,P).

I want to output the updated parameters when the impact event is triggered using fprintf function in the EventCallback function illustrated as follows :

function [stop,Ye,Pout] = impactEventCallback(te,ye,ie,Pin)
                
                % ...  parameters updating process
                fprintf("The updated parameters are : %e", Pout)
end

However, when I simulate the impact process, there is no output display.

Can anyone give me some advices about how to output parameters when the impact event is triggered.

[Chuguang Pan]

I test the impactEventCallback function with different parameters updating raw, nevertheless the simulation results do not change. I suspect that the impactEventCallback function does not be called although I have setted odeEvent object with following :

E = odeEvent("EventFcn",@(t,Y,P) impactEvent(t,Y,P),"Direction","ascending","CallbackFcn",@(te,Ye,ie,P) impactEventCallback(te,Ye,ie,P),"Response","proceed");

[charan]

Hi Chuguang,

Did you try with the "Response" parameter set to "callback"?

[Chuguang Pan]

@sai charan sampara thanks for your reply, I find that the issue is just as you said. I set the "Response" to "proceed". After I set it to "callback", it worked correctly!

Answer 1

[charan]

Hi Chuguang,

The call back function is called whenever the event occurs, only if the "Response" parameter is set to "callback". If the "Response" parameter is set to "proceed" then the solver logs the event and continues integrating. So to resolve your issue change the "odeEvent" definition as follows:

E = odeEvent("EventFcn",@(t,Y,P) impactEvent(t,Y,P),"Direction","ascending","CallbackFcn",@(te,Ye,ie,P) impactEventCallback(te,Ye,ie,P),"Response","callback");