How to enable variable output signal size?

Hello everyone,

I am trying to simulate a radar sensor for a collision detection. Here I am using LinePickSensor with 5 lines.

The two plates move back and forth along the middle line following sine functions.

From the block VR Source, I need to get pickedPoint as output.

The pickedPoint output has a dimension of 5x3 at the beginning, since all of the lines are in contact with the bigger plate. However, once the plate has moved too far away from the cylinder, the 4 inclined lines lose contact with the plate and only the middle line penetrates the bodies. Therefore, the output signal dimension changes into 1x3 and there is an error report:

An error occurred while running the simulation and the simulation was terminated

Caused by:

• Error reported by S-function 'vrsfunc' in 'LinePickSensor_test/VR Source': Signal dimension 1 of output port 2 has changed from 5 to 1. Please consider enabling variable output signal size.

How to enable variable output signal size? Is it possible to set the values into 0 if there is no output?

Answer 1

[Jan Houska]

Hi Leonardus,

there is a checkbox labeled Allow variable-size output signals in the VR Source block dialog. This must be selected (enabled) if your signal changes its size during simulation, as is the case with the LinePickSensor. Please verify if you have this checkbox selected.

Good Luck, Jan

[Leonardus Yudha Septian Sutanto]

Hi Jan,

Thanks for your answer. I have just selected the checkbox but there is another error:

Simulink cannot propagate the variable-size mode from the 'Output Port 2' of 'LinePickSensor_test/VR Source' to the 'Input Port 1' of 'LinePickSensor_test/Multiport Selector'. This input port expects a fixed-size mode. Examine the configuration of 'LinePickSensor_test/Multiport Selector' for one of the following scenarios: 1) the block does not support variable-size signals; 2) the block supports variable-size signals but needs to be configured for them.

It seems that the Multiport Selector, which I connected with the Collision_Sensor.pickedPoint Output Port doesn't support variable-size signals.

Best Regards,

Yudha

[Jan Houska]

Hi Yudha,

not all blocks support variable-size signals, you must use a block that does. Please see https://www.mathworks.com/help/simulink/ug/variable-size-signal-basics.html for more information.

Good Luck, Jan