Community Profile

# Jim Riggs

### Missile Defense Agency - Advanced Technology Group

242 2017 年以降の合計貢献数

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.

#### Jim Riggs's バッジ

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 ...

5日 前 | 0

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...

5日 前 | 1

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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.

6日 前 | 0

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 ...

6日 前 | 0

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

6日 前 | 0

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...

7日 前 | 0

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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...

7日 前 | 0

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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. ...

10日 前 | 1

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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...

10日 前 | 0

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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...

10日 前 | 0

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...

11日 前 | 0

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...

19日 前 | 0

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...

20日 前 | 0

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

22日 前 | 0

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

23日 前 | 0

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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.

26日 前 | 0

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...

27日 前 | 0

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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 ...

29日 前 | 1

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 -...

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

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...

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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'...

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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...

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...

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

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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ヶ月 前 | 0

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minimum feret diameter of particle

2ヶ月 前 | 0

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ヶ月 前 | 0

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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ヶ月 前 | 0

Runge kutta order 2 by hand
In the statement Y(1) = [t(1);y(1)] the simi-colon ";" indicates you are attempting to put 2 rows of numbers into a single ro...

2ヶ月 前 | 0