Simulink Product Block Dimension Issue.

Hi everyone,

I have created a simulink model (shown below) to determine robot joint velocities () for given robot end-effector velocities () by using the following relation:

The pseudo-inverse of the jacobian (called Jpinv in the model) is fed to a product block to be post-multiplied with the joint velocities (called pdot) to produce the end-effector velocites (called qdot).

However I get the following error messages:

Why doesn't the Product block recognize the dimensions of the Jpinv matrix? Because Simulink states [7x6] at the exit of the Function block and then suddenly loses this information when it enters at the Product block? And from Linear Algebra I know that a [7x6] matrix times a [6x1] vector should yield a [7x1] matrix of joint velocities qdot.

Does anybody know how I can fix this issue to get the correct multiplication result?

Thanks in advance,

Mike

Answer 1

[Jonas]

You need to set the 'Multiplication' option of your Product block to 'Matrix(*)'.

Answer 2

[Luca]

What blocks do you need to visualize the product of a pressure for a surface and obtain a force?