## Ramakrishnan

Dr. Ramakrishnan Vaidyanathan

## 259 Reputation

4 years, 358 days

## Social Networks and Content at Maplesoft.com

I have retired as Professor-Mechanical in Sri Venkateswara College of Engineering and Technology under Anna University affiliated colleges in Tamil Nadu, India. I have 19 years of Industrial and 20 years of teaching experience. I am learning Maple for the past four and half years hoping to make at least one appreciable maple presentation.

## Manipulating equations and reassigning i...

I dragged into model space prismatic FixedFrame and RigidBody components and prismatic joint along y axis. I also set mass m = 1 kg. The manual says set K_S = K_S and K_K_d in inspector parameter setting. It did not work out. So i set values 12 and 0.1 for K_S and K_d. I sreated subsystem sub of rigidBody and followed the following instructions,

Quote" PrismaticJoint.PlacethePrismaticjointandRigidBodyinasubsystemcalledsub.Thisallowsthe EquationTemplatetogenerateequationsspecificallyfortheselectedsubsystem.

After this i wanted to modify the equations. I could not. The same equation is reassigned.

Parameter and variable rows - are as shown in manual, but a blank row not available for user's use. But how do i get the variable x(t) there and rename it?

Thanks for an example of this chapter with an application of its use., if available with anyone?

Ramakrishnan V

## Require Maplesim plot for given x,y data...

I have made a program to plot y(t) vs x(t). Can you please modify to plot y vs x data from an excel file.

Given x in A column and y in B column in 5 rows.

Example data: [[1,1],[2,4],[3,9],[4,16],[5,26]]

StLine_VRK.msim

Thanks.

Ramakrishnan V

## DC Motor example - How do i get output i...

I followed the basic example RLS circuit first. It worked out well for R = 24 ohms, L = 160 mHand C = 200 microF. Signal is step input h = 1 and  t0 =  0.1 s. Simulation td = 0.5 s

When I extended it for DC motor, the output for torque (tou) and speed (w) not plotted for h = 1  t0 =  1s and simulation td = 5 s for the same parameters as above the output required (shown in manual) is not coming. Is it because default values shown were different? Then how do i change? I am enclosing the file for view and help.

DCmotort_model1.msim

Thanks.

Ramakrishnan V

## How do I plot four second order curves i...

Maple 2017

[[1000, 20], [2000, 25], [3000, 24], [4000, 23], [5000, 24]];
[[1000, 20], [2000, 25], [3000, 24], [4000, 23], [5000, 24]]
data1 := [[1000, 20], [2000, 21], [3000, 32], [4000, 23], [5000, 23]]; 'data1';
data1
a*x^3+b*x^2+c*x+d;
3      2
a x  + b x  + c x + d
x;
x
Equn1 := CurveFitting[LeastSquares]([[1000, 20], [2000, 25], [3000, 24], [4000, 23], [5000, 24]], x, curve = a*x^3+b*x^2+c*x+d);
plot(Equn1,x= 1000..5000)

Least Squares Approximation

Calculate a least squares approximation using specified data points.

Theoretical Curves for the Two-Stroke Engines and Four-Stroke Engines Brake Power Vs Brake Efficiency

List of Data Points:

 >
 (1)
 >
 (2)

Fitting Curve:

 >
 (3)

Independent Variable:

 >
 (4)

Least Squares Curve:

 >
 > plot(Equn1,x= 1000..5000)
 >

 >
 (5)

Least Squares Fit of Data by a Specified Curve

List of Data Points:

 >
 (6)

Fitting Curve:

 >
 (7)

Independent Variable:

 >
 (8)

Least Squares Curve:

 >
 (9)

 (10)

The above command plots one curve alright. I want four such curves to go in the same figure using command like

plot(Equn1,Equn2,Equn3,Equn4,view(x=1000..5000)

I am not getting by the above command what I want. Can any one help. A shortcut method is required for me to repeat many times.

Thanks for help.

Ramakrishnav V

## Multiplication with transpose matrix ...

Maple

 = I am not getting the answer. I want to get the answer for this product of matrix and its tranport. I do not want to create transport matrix again for this calculation. The transporse matrix b is  =  is equal to  = For large matrices i cannot do this. Hence this request.Any one please send the code. Thanks.

Ramakrishnan V

rukmini_ramki@hotmail.com

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