PX4 SITL with Simulink-Based Plant Model

Hello, I'm develeoping a simple observer-based controller and I'm trying to implement it on PX4 stack. I'm developing a SITL scheme with Simulink-Based plant model as shown in Monitor and Tune PX4 Host Target Flight Controller with Simulink-Based Plant Model - MATLAB & Simulink - MathWorks. I developed a simple simulink model to check connetivity between my controller and the plant but there is a problem. I'm able to follow all the steps in the tutorial mentioned above but at the end I get the following error in the Simulink controller model:

action: EXT_INIT Creating Target Handler (XCP on TCP/IP)... Build directory: C:\Users\paolo\OneDrive\Documenti\Tesi_magistrale\SITL\partialInformation_controller_SITL_Simulink_ert_rtw Target name: 127.0.0.1 Target port: 17725 action: EXT_CONNECT Connecting to the target...

External Mode Open Protocol Connect command failed

Caused by:

• Could not connect to target application: XCP TCP/IP error: Connect failed

Component:Simulink | Category:Block diagram error

Unable to connect to the 'PX4 Host Target' target for 'partialInformation_controller_SITL_Simulink'.

I think the problem is on model side beacuse if I run the quadcopter model in the example Monitor and Tune PX4 Host Target Flight Controller with Simulink-Based Plant Model - MATLAB & Simulink - MathWorks my controller seems to connect succesfully with this model. This is my model for test connectivity, I'm trying to publish a simple message HIL_GPS with a dummy altitude:

And this is the controller I have developed:

Someone can help me?

Thanks in advice,

Paolo

[Manoj Velmurugan]

Did the host target window launch for you?

Also check if some other application is blocking 17725 port.

Answer 1

[Manoj Velmurugan]

PX4 Host target waits until it receives the HIL_SENSOR message. PX4 Host target has not started running as there is no HIL_SENSOR message in your plant model.

For more information, see the following lines in Firmware\src\modules\simulator\simulator.cpp

#if defined(ENABLE_LOCKSTEP_SCHEDULER)

		// We want to prevent the rest of the startup script from running until time
		// is initialized by the HIL_SENSOR messages from the simulator.
		while (true) {
			if (Simulator::getInstance() && Simulator::getInstance()->has_initialized()) {
				break;
			}

			system_usleep(100);
		}
#endif
       

[Paolo]

Hi Manoj, thank for the answer. I added the HIL_SENSOR block and all seems to work weel. Thanks!