Community Profile

photo

Jim Riggs


Last seen: Today

Missile Defense Agency - Advanced Technology Group

243 total contributions since 2017

Developing simulations for the Missile Defense Agency - Advanced Technology group
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.

Contact

Jim Riggs's Badges

  • 24 Month Streak
  • Revival Level 2
  • Solver
  • Knowledgeable Level 3
  • Thankful Level 1
  • First Answer

View details...

Contributions in
View by

Answered
Ballstic Impact of Bullets on armor
I don't know af any specific ballistics tools. You should browse the a list of Matlab products at this link: Matlab Products

4 days ago | 0

| accepted

Answered
How to find theta and theta dot in a simple pendulum simulation in MATLAB.
I'm not sure at all what your system equations are. The first rule of dynamics is where you have translational modes of motion ...

11 days ago | 0

Answered
What is a "system variable" in a Simulink model?
In this context, the "system" is the device that you are modelling. Therefore, a "system variable" is one of the variables in y...

12 days ago | 1

| accepted

Answered
Undefined function 'simset' for input arguments of type 'char'.
simset is an obsolete function. See documentation here. It says to use the Configuration Parameters dialog box.

12 days ago | 0

Answered
Newtons method for finding minimum of a function.
Here is another variation; function [f,g,h] = myfunction(x) f1 = @(z) exp(2*sin(z))-z; %function dx ...

13 days ago | 0

Answered
help me in trying to solve the secant method
Try preallocating x, right after you define n: n = 100; x = nan(1,n); ...

13 days ago | 0

Answered
trying to calculate the central diff approximation
There is a Matlab function "diff" which will do this. Otherwise, your subscripts must all match (2:end-1) Adi_1 = diff(Vdi_1...

13 days ago | 0

| accepted

Answered
Performing calculations (Newton's method) over values in loop
Yes, your loop is not quite right. Notice your placement of the three lines i=1; converge = false; po = p_init(1); These t...

14 days ago | 0

| accepted

Answered
Draw a circle for arbitrary orientation on spherical surface
My approach is to define the circle around the X-axis, then rotate it into the desired position through a Yaw-Pitch rotation. ...

16 days ago | 1

| accepted

Answered
the meaning of basic matlab words
an argument is a constant or variable that you provide to a function; e.g. sin(x) % here x is the argument to the function sin...

17 days ago | 0

| accepted

Answered
How to alter Comet Speed
I don't see a way to control the speed of the comet function. There is a discussion of controlling the speed of an animated lin...

17 days ago | 0

Answered
Incorrect Answer Calculated For Force Calculation
It is assumed that you want to find F3 and y such that the system is in equilibrium (this is not stated) (and I disagree with D...

18 days ago | 0

Answered
Transformation Matrix Between Two Cartesian Systems
This is a very generic question and there are many ways to answer. It depends on what information you have about the two coordi...

26 days ago | 0

Answered
Why is ode45 changing the value of the state variable between calls to my dynamics function?
ode45 implements the Dormand-Prince method which is an embedded 4th / 5th order Runge-Kutta method. For every "step" in the sol...

27 days ago | 0

| accepted

Answered
Implement friction into a model, related to the velocity. (Missile Launch)
This question is familiar. look here.

28 days ago | 0

Answered
How to make a marker circle bold?
plot(x, y, 'ro', 'linewidth',2);

30 days ago | 0

| accepted

Answered
how can i resolve this equation Runge kutta method
Ths is the equation for a parabola. y'' = -1 y' = -y y = -1/2 y^2 No need for a numerical approximation.

1 month ago | 0

Answered
Missile Lauch friction gamma factor - Output deviating from desired output, please help!
Step 1: Draw a free body diagram that shows the body with all of the forces that act on it and the coordinate frame(s) that are...

1 month ago | 0

| accepted

Answered
How to calculate the slope from geopraphical coordinates?
First of all, you should consider the relationship between the WGS84 lat/lon/alt and the ECEF frame. Altitude is perpendicular ...

1 month ago | 1

Answered
calculate rotation matrix in 3D
I'll assume that we make the reference frame right-handed by negating the axis_3 vector such that axis_1 = [2.7239 -0.2014 -...

2 months ago | 1

| accepted

Answered
Translational motion of a rotating object.
To begin, Chasles' theorem states that translational motion and rotational motion obey the law of superposition. Therefore, you...

2 months ago | 0

Answered
change variable value based on other variable in if loop
Your input command is requesting a string input: in1 = input('first: ','s'); in2 = input('second: ','s'); This results in in1...

2 months ago | 1

| accepted

Answered
I don't know the problem involved Backward difference.
I am assuming that your question is that you don't understand Simpson's rule. Below is an exerpt from Wikipedia: Simoson'...

2 months ago | 0

| accepted

Answered
1-2-1 or X-Y-X rotation matrix not supported
I recently cataloged all of the permutations of the 2 and 3 axis planar rotations. It is easy to write your own functions. See...

2 months ago | 0

Answered
Extracting data from simout MATLAB work space
simout is a timeseries structure. I like to extract separate vectors from the structure, for example: t = timout.time(simout.t...

2 months ago | 0

Answered
Where can I publish Matlab-compiled software?
If you want to share the source code, you can post it on Matlab File Exchange

2 months ago | 0

| accepted

Answered
In my Simulink model I would like to conditionally write output data to selectable .mat files in different relative directories.
This sounds like a rather sophisticated way of constructing output. I'm not sure if that is easily acomplished with the "to fil...

2 months ago | 0

| accepted

Answered
minimum feret diameter of particle
https://blogs.mathworks.com/steve/2018/02/20/minimum-feret-diameter/?s_tid=answers_rc2-1_p4_MLT

2 months ago | 0

Answered
Vlookup equivalent function for matlab
If your data is in a 2D table (matrix) and you want to locate a column that matches the exact value from another column, then lo...

2 months ago | 0

| accepted

Answered
How calculate the second and third numerical derivative of one variable f(x)
The Matlab "diff" function is basically the Backward difference formula. There are much more accurate ways to compute numerical...

2 months ago | 0

Load more