Developing simulations for the Missile Defense Agency - Advanced Technology group

30+ years experience in missiles, smart munitions and other aerodynamic systems.

Answered

Numerical Integration in Matlab

There seem to be two problems: 1) your function "fun" returns "NaN" at zero, so you cannot integrate starting from zero. You n...

Numerical Integration in Matlab

There seem to be two problems: 1) your function "fun" returns "NaN" at zero, so you cannot integrate starting from zero. You n...

19 hours ago | 0

| accepted

Answered

Simulink counter block having an initial starting value of -1

Yes, the two counter blocks in the library do not allow you to set the initial value. Whenever I need to use a counter, I usual...

Simulink counter block having an initial starting value of -1

Yes, the two counter blocks in the library do not allow you to set the initial value. Whenever I need to use a counter, I usual...

3 days ago | 1

| accepted

Answered

Finding the roots of an equation using Newton-Raphson method but I don't know the equation!

You use a numerical approximation for the derivative. Start at some initial guess for x & y. take a small step, and compute th...

Finding the roots of an equation using Newton-Raphson method but I don't know the equation!

You use a numerical approximation for the derivative. Start at some initial guess for x & y. take a small step, and compute th...

6 days ago | 1

Answered

Implementing Angles as an input in Simulink

It appears (based on the icon on the block) that the block labeled "Robot Controler" is a Matlab function block. In order to a...

Implementing Angles as an input in Simulink

It appears (based on the icon on the block) that the block labeled "Robot Controler" is a Matlab function block. In order to a...

15 days ago | 0

Answered

Pendulum using Runge Kutta

Yes, there are a few things wrong with this code. James Tursa has identified one obvious error. Another problem is with the lo...

Pendulum using Runge Kutta

Yes, there are a few things wrong with this code. James Tursa has identified one obvious error. Another problem is with the lo...

29 days ago | 0

| accepted

Answered

How to return the index of time steps in Simulink?

One way to do this is to put a step counter in the block. This will keep track of the number of times the block is executed. T...

How to return the index of time steps in Simulink?

One way to do this is to put a step counter in the block. This will keep track of the number of times the block is executed. T...

1 month ago | 0

Answered

Why is my code not working?

Not entirely sure if this is the reference in the error message, but this line has unballanced parentheses: f = (1/(t-t^(-1))*...

Why is my code not working?

Not entirely sure if this is the reference in the error message, but this line has unballanced parentheses: f = (1/(t-t^(-1))*...

2 months ago | 0

Answered

SIR Simulink Model Function Block

In the Simulink library browser, on the "sources" pallet, you will find a "clock" function. Use this to create a time signal. ...

SIR Simulink Model Function Block

In the Simulink library browser, on the "sources" pallet, you will find a "clock" function. Use this to create a time signal. ...

4 months ago | 0

Answered

How can one do this calculation?

Look into using logical indexing. Not my strong point, but for example, if A is the 3 x 10 matrix, you can select all cases whe...

How can one do this calculation?

Look into using logical indexing. Not my strong point, but for example, if A is the 3 x 10 matrix, you can select all cases whe...

4 months ago | 0

Answered

Kalman Filtering for smoothing GPS speed data

The problem is with this line: P = (1-KG)*P; This causes the gain P to continuously decrease. After a while, the gain P is ve...

Kalman Filtering for smoothing GPS speed data

The problem is with this line: P = (1-KG)*P; This causes the gain P to continuously decrease. After a while, the gain P is ve...

6 months ago | 1

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Answered

numerical derivate and central difference

Here are some Numerical difference formulas using the central difference method (substitute dt = h). You can find more formulas...

numerical derivate and central difference

Here are some Numerical difference formulas using the central difference method (substitute dt = h). You can find more formulas...

7 months ago | 1

Answered

Meaning of the following: function [y1,...yn] = input()

It simply means that there are no user inputs to this function. The long list of variable names are returned from the function....

Meaning of the following: function [y1,...yn] = input()

It simply means that there are no user inputs to this function. The long list of variable names are returned from the function....

8 months ago | 0

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Answered

Angle Between two vectors.

Given two vectors A and B, the dot product of the two vectors (A dot B) gives the product ABcos(ang), so to get just the angle, ...

Angle Between two vectors.

Given two vectors A and B, the dot product of the two vectors (A dot B) gives the product ABcos(ang), so to get just the angle, ...

8 months ago | 0

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Answered

Is it possible to summarize this code?

You could use a switch case structure, that would be a bit more compact. it would look like this: switch davar1.CC_CHECK ...

Is it possible to summarize this code?

You could use a switch case structure, that would be a bit more compact. it would look like this: switch davar1.CC_CHECK ...

8 months ago | 2

| accepted

Answered

help fixing the Heuns method

Heun's method is otherwise known as "explicit trapezoidal method", "improved Euler's method" or "modified Euler's method". Th...

help fixing the Heuns method

Heun's method is otherwise known as "explicit trapezoidal method", "improved Euler's method" or "modified Euler's method". Th...

8 months ago | 0

Answered

I need help coding a human cannonball ignoring air resistance

Assuming zero drag and relatively low muzzle velocity ( acceleration due to gravity = constant), the point-mass trajectory can b...

I need help coding a human cannonball ignoring air resistance

Assuming zero drag and relatively low muzzle velocity ( acceleration due to gravity = constant), the point-mass trajectory can b...

9 months ago | 1

Answered

Runge Kutta 4th Order Method

I think the problem is the T argument. in k1 you have a capital T, which is a 3-vector in k2, k3, and k4 it is a lower case t,...

Runge Kutta 4th Order Method

I think the problem is the T argument. in k1 you have a capital T, which is a 3-vector in k2, k3, and k4 it is a lower case t,...

9 months ago | 0

Answered

Matlab Homework that im struggling with

To prompt a user to enter a value, try: x = input('Enter the number of equations (from 2 to 5): \n')

Matlab Homework that im struggling with

To prompt a user to enter a value, try: x = input('Enter the number of equations (from 2 to 5): \n')

9 months ago | 0

Answered

I need help with this script

Try this: T = input('Enter your temperature') if T<=96 disp('You are either hypothermic or a zombie') elseif T<99 d...

I need help with this script

Try this: T = input('Enter your temperature') if T<=96 disp('You are either hypothermic or a zombie') elseif T<99 d...

9 months ago | 0

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

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

10 months ago | 0

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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 ...

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 ...

10 months 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...

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...

10 months ago | 1

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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.

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.

10 months 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 ...

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 ...

10 months 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); ...

help me in trying to solve the secant method

Try preallocating x, right after you define n: n = 100; x = nan(1,n); ...

10 months 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...

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...

10 months 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...

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...

10 months 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. ...

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 months 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...

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 months 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...

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 months ago | 0