Bill Goodwine's Courses

Reading: You should have read all of Chapter 8 by now. Also, Chapter 9, sections 9.1-9.5.

Exercises: 9.1 - 9.5.

For 9.3 use Simulink and also use the linear equation, not the nonlinear ones.

by "linear" do you mean we should use the equation without the cos term?

nsolomon wrote:by "linear" do you mean we should use the equation without the cos term?

Yes, cos(theta) is nonlinear in theta.

For 9.3:

Do you want us to use Simulink in addition to a Fortran/C code for a numerical solution, or just Simulink?

Thanks

mkiener wrote:For 9.3:

Do you want us to use Simulink in addition to a Fortran/C code for a numerical solution, or just Simulink?

Thanks

Just simulink.

Professor,

For problem 9.3, I end up with a (constant / s) term that needs to be added to the kp(th_d - th) before being multiplied by the transfer function. Where in simulink would I find an operator that allows for constants and "s" to be added to block diagrams?

Sorry. To be clear, I am looking to create a block diagram similar to that on page 224, Figures 8.22 and 8.23, how would I add the (mgl/s) term?

ngeraci wrote:Professor,

For problem 9.3, I end up with a (constant / s) term that needs to be added to the kp(th_d - th) before being multiplied by the transfer function. Where in simulink would I find an operator that allows for constants and "s" to be added to block diagrams?

You use a sum element just like in the Figure on p. 224. The constant over s term can be a step, and inside that you can specify the magnitude.

Simulink sends an error message when I try to specify the magnitude as (1/s). is there another way I might be able to include an "s" term?

ngeraci wrote:Simulink sends an error message when I try to specify the magnitude as (1/s). is there another way I might be able to include an "s" term?

It's a step.

Professor,

I get this warning when I try to run my simulink models:

"Warning: Using a default value of 0.2 for maximum step size. The
simulation step size will be equal to or less than this value. You
can disable this diagnostic by setting 'Automatic solver parameter
selection' diagnostic to 'none' in the Diagnostics page of the
configuration parameters dialog"

What does this mean?

Thanks!

thenisey wrote:Professor,

I get this warning when I try to run my simulink models:

"Warning: Using a default value of 0.2 for maximum step size. The
simulation step size will be equal to or less than this value. You
can disable this diagnostic by setting 'Automatic solver parameter
selection' diagnostic to 'none' in the Diagnostics page of the
configuration parameters dialog"

What does this mean?

Thanks!

It seems to me that it's telling you that it's setting the integration step size, not you.

For 9.4, can the numerical solution be found using MATLAB?

Apuente wrote:For 9.4, can the numerical solution be found using MATLAB?

Yes.

Professor Goodwine,

What do we need to write down/print out to prove that we did problem 9.3? Are we to print different graphs for different kp, kd, ki? Or can we just print out our simulink block diagram?

Thanks!

lawnoy wrote:Professor Goodwine,

What do we need to write down/print out to prove that we did problem 9.3? Are we to print different graphs for different kp, kd, ki? Or can we just print out our simulink block diagram?

Thanks!

You need to submit something to show the effect of changing those values. If you can do it without wasting too much paper, that's great, but you the point of the problem was to verify those things.