30+ years experience in missiles, smart munitions and other aerodynamic systems. Specializing in systems engineering, aerospace systems design, simulation and modeling, aerodynamics, and numerical analysis.

Currently developing simulations for the Advanced Technology group of the Missile Defense Agency

Question

What is the best way to insure that all of my functions are using the same constant values?

I want to make sure that my functions are all using the same values for physical constants, like earth radius, elipsoidal flatte...

3 days ago | 2 answers | 0

Answered

Why will these plots not plot on the same graph?

You need to turn on "hold" mode to plot more than one plot on the same axes. If you do not use hold, the next plot replaces the...

Why will these plots not plot on the same graph?

You need to turn on "hold" mode to plot more than one plot on the same axes. If you do not use hold, the next plot replaces the...

5 days ago | 0

Answered

Communication delay & jitter delay modelling

Here is my interpretation of what you are asking. It seems that this woud be very easy in Simulink. You have signal PT which i...

Communication delay & jitter delay modelling

Here is my interpretation of what you are asking. It seems that this woud be very easy in Simulink. You have signal PT which i...

5 days ago | 0

Answered

Simulink switch that is based on probability

This seems to work for me (The uniform random number is set to a range of 0 to 1):

Simulink switch that is based on probability

This seems to work for me (The uniform random number is set to a range of 0 to 1):

7 days ago | 0

| accepted

Answered

Rotating a coordinate with a rotation matrix

There seems to be some confusion regarding what the coordinate rotation transform is doing. One way to think about it is that i...

Rotating a coordinate with a rotation matrix

There seems to be some confusion regarding what the coordinate rotation transform is doing. One way to think about it is that i...

10 days ago | 0

| accepted

Answered

How can I position my textbox exact position in my plot?

Yes, this is possible to do, but it is complicated. When you place graphics in a figure window, they are located based on the f...

How can I position my textbox exact position in my plot?

Yes, this is possible to do, but it is complicated. When you place graphics in a figure window, they are located based on the f...

14 days ago | 0

| accepted

Answered

Call function by path or namespace?

One way to approach this is to create a separate folder (that is not on the Matlab path) for your project. When you set the Mat...

Call function by path or namespace?

One way to approach this is to create a separate folder (that is not on the Matlab path) for your project. When you set the Mat...

17 days ago | 0

Answered

Difference between a vector and a bus signal

A bus signal is like a C++ structure. It can contain a variety of different signal types. A vector is an array, all elements a...

Difference between a vector and a bus signal

A bus signal is like a C++ structure. It can contain a variety of different signal types. A vector is an array, all elements a...

17 days ago | 0

Answered

How to call .m file from an other .m file?

Use the command run(filename) Any variables defined in the script are available in the Matlab workspace.

How to call .m file from an other .m file?

Use the command run(filename) Any variables defined in the script are available in the Matlab workspace.

17 days ago | 0

Answered

How would you plot a graph which a ball then rolls down (say a y=x^2 graph)

Here is a model for the kinematics. clear data % I use data to save values in the time loop func = @(x) x.^2; % this is ...

How would you plot a graph which a ball then rolls down (say a y=x^2 graph)

Here is a model for the kinematics. clear data % I use data to save values in the time loop func = @(x) x.^2; % this is ...

22 days ago | 0

Answered

Von Karman Wind Turbulence Model

V is the true airspeed. V is a scalar, and is used to calculate the scalar components of the turbulence field. The documentati...

Von Karman Wind Turbulence Model

V is the true airspeed. V is a scalar, and is used to calculate the scalar components of the turbulence field. The documentati...

24 days ago | 0

Answered

How to find the angle between two quaternions?

I am more comfortable working with direction cosine matrices, so the way I would do this is to first convert the quaternions to ...

How to find the angle between two quaternions?

I am more comfortable working with direction cosine matrices, so the way I would do this is to first convert the quaternions to ...

1 month ago | 1

Answered

Eliminate algebraic loop without using memory block

Here is an interesting article on algebraic loops and memory blocks. (pertaining to continuous time models) https://blogs.math...

Eliminate algebraic loop without using memory block

Here is an interesting article on algebraic loops and memory blocks. (pertaining to continuous time models) https://blogs.math...

1 month ago | 0

Answered

how to I add add a text in the Notes section (below the ppt slide)

on the VIEW tab, click on "notes page"

how to I add add a text in the Notes section (below the ppt slide)

on the VIEW tab, click on "notes page"

1 month ago | 0

Answered

calculate difference of euler angles between two dynamic moving objects

You have two objects described in a common reference frame. Lets call the objects A and B, and the frame is the I frame. So if...

calculate difference of euler angles between two dynamic moving objects

You have two objects described in a common reference frame. Lets call the objects A and B, and the frame is the I frame. So if...

1 month ago | 1

| accepted

Answered

Is it possible to only rename instances of a variable that appear in the code after the point at which you edit the variable selected? (shift+enter)

I use a tool called UltraEdit. It has that capability. In the find/replace tab there is a checkbox for "replace all is from t...

Is it possible to only rename instances of a variable that appear in the code after the point at which you edit the variable selected? (shift+enter)

I use a tool called UltraEdit. It has that capability. In the find/replace tab there is a checkbox for "replace all is from t...

1 month ago | 0

Answered

program to find velocity of a UAV

This is a fun problem (aircraft design). I guess it's OK to give an answer on this, since it was homework 8 years ago! A quick...

program to find velocity of a UAV

This is a fun problem (aircraft design). I guess it's OK to give an answer on this, since it was homework 8 years ago! A quick...

1 month ago | 0

Answered

how can i calculate the energy of the pixel in the image??

Here are a couple possible references https://www.mathworks.com/matlabcentral/answers/63441-to-find-energy-of-each-pixel-from-a...

how can i calculate the energy of the pixel in the image??

Here are a couple possible references https://www.mathworks.com/matlabcentral/answers/63441-to-find-energy-of-each-pixel-from-a...

2 months ago | 0

Answered

simulink output size is not same as input size

The answer has to do with how you are saving variable "temp" from Simulink, but I cannot tell from the screenshot how this is be...

simulink output size is not same as input size

The answer has to do with how you are saving variable "temp" from Simulink, but I cannot tell from the screenshot how this is be...

2 months ago | 0

Answered

Eulers method range issue question

In your code, you specify: R=[1:16]; h=0.2; ic=4; Then you call the function [t,y]=myEuler(f,R,ic,h) Inside myEuler, it co...

Eulers method range issue question

In your code, you specify: R=[1:16]; h=0.2; ic=4; Then you call the function [t,y]=myEuler(f,R,ic,h) Inside myEuler, it co...

2 months ago | 1

Answered

How do you use Euler's Method to approximate the solution?

Euler's method approximates the area under a curve by using rectangular segments. The figure illustrates this process: You s...

How do you use Euler's Method to approximate the solution?

Euler's method approximates the area under a curve by using rectangular segments. The figure illustrates this process: You s...

2 months ago | 0

| accepted

Answered

Coorindate transforms to a satellite reference frame

In order to answer this question, we need a good definition of the coordinate frames involved. The only way to do this is to dr...

Coorindate transforms to a satellite reference frame

In order to answer this question, we need a good definition of the coordinate frames involved. The only way to do this is to dr...

2 months ago | 0

Answered

How do I execute a function only one time in Simulink?

This is what rate transition blocks were created for. You might want to try this approach. Simply insert a rate transition blo...

How do I execute a function only one time in Simulink?

This is what rate transition blocks were created for. You might want to try this approach. Simply insert a rate transition blo...

2 months ago | 1

Answered

How to substract one number from many numbers?

W = x - 0.6 Or, if you want to actualy subtract x from 0.6 it would be: W = -x + 0.6

How to substract one number from many numbers?

W = x - 0.6 Or, if you want to actualy subtract x from 0.6 it would be: W = -x + 0.6

2 months ago | 0

| accepted

Answered

How do I export a vector to workspace in simulink?

It'a actually very easy. Simulink has a block for combining two signals, called a "mux" block. Simply combine the two signals ...

How do I export a vector to workspace in simulink?

It'a actually very easy. Simulink has a block for combining two signals, called a "mux" block. Simply combine the two signals ...

3 months ago | 0

Answered

thermodynamic properties of water in simulink

Sounds like a perfect application for using a table look-up. For a function of two variables, simulink has a "2-D Lookup Table...

thermodynamic properties of water in simulink

Sounds like a perfect application for using a table look-up. For a function of two variables, simulink has a "2-D Lookup Table...

3 months ago | 0

Answered

Index exceeds the number of array elements (1)

In the calculation of xdot I see subscripted references for x (up to 12) and u (up to 4). You should check the size of x and u ...

Index exceeds the number of array elements (1)

In the calculation of xdot I see subscripted references for x (up to 12) and u (up to 4). You should check the size of x and u ...

3 months ago | 0

| accepted

Answered

how simulate PI ?

Yes, it's that easy. Did you try it? What are the results?

how simulate PI ?

Yes, it's that easy. Did you try it? What are the results?

3 months ago | 1

Question

Is Walter Roberson a real person, or is he some kind of Matlab AI robot?

Just curious!

4 months ago | 8 answers | 13

Answered

solve 4th order ode in simulink

Your diagram looks reasonable to me and it could work, but its hard to tell from a screen shot - especially when the block title...

solve 4th order ode in simulink

Your diagram looks reasonable to me and it could work, but its hard to tell from a screen shot - especially when the block title...

4 months ago | 1