Items tagged with dynamics

I'd like to pay attention to an article J, B. van den Berg and J.-P. Lessard, Notices of the AMS, October 2015, p. 1057-1063.  We know numerous  applications of CASes to algebra. The authors present such  applications to dynamics. It would be interesting and useful to obtain  opinions of Maple experts on this topic.

Here is its introduction:

"Nonlinear dynamics shape the world around us, from the harmonious movements of celestial bod-
ies,  via  the  swirling  motions  in  fluid  flows,  to the  complicated  biochemistry  in  the  living  cell.
Mathematically  these  beautiful  phenomena  are modeled by nonlinear dynamical systems, mainly
in  the  form  of  ordinary  differential  equations (ODEs), partial differential equations (PDEs) and
delay differential equations (DDEs). The presence of nonlinearities severely complicates the mathe-
matical analysis of these dynamical systems, and the difficulties are even greater for PDEs and DDEs,
which are naturally defined on infinite-dimensional function spaces. With the availability of powerful
computers and sophisticated software, numerical simulations have quickly become the primary tool
to study the models. However, while the pace of progress increases, one may ask: just how reliable
are our computations? Even for finite-dimensional ODEs, this question naturally arises if the system
under  study  is  chaotic,  as  small  differences  in initial conditions (such as those due to rounding
errors  in  numerical  computations)  yield  wildly diverging outcomes. These issues have motivated
the development of the field of rigorous numerics in dynamics"





(in spanish)


Lenin Araujo Castillo



Derive the orbit of the Moon around the Earth by doing a Verlet algorith of Molecular Dynamics simulation. Use one hour for your step τ. Place the stationary Earth at the origin of the Cartesian system. For initial conditions, use the position and the speed of the Moon when it is at its apogee (furthest from Earth). Plot the orbit.

Hi! I'm having trouble with the MapleSim "Equation Extraction" template. I have an extremely simple dynamics scenario with RigidBody at a particular position in a world; when the simulation starts, the body should simply start fallin with a constant acceleration, and I'm looking to extract kinematic equations for this situation.

However, the problem I have with the extracted equations is that they contain some rotational dependent terms that I wish to avoid - a lot of sines and cosines with arguments that I actually cannot match up to any variables in the model, or when I enable quaternion representation, terms like this:

What I don't understand is what exactly these rotation terms represent. The object should be falling straight downwards, and gravitation should be applied straight downwards, and when I start the simulation it does run through, also indicating that there should be no unbound variables. I'm not sure exactly what parameters in the Modelica model do they correspond to? I did not find any such angles in the object settings. And can I ask MapleSim to generate equations without these unbound rotation variables?

The equations of motion for a rigid body can be obtained from the principles governing the motion of a particle system. Now we will solve with Maple.

(in spanish)


Lenin Araujo Castillo

Corrección ejercico 4


4.- Cada una de las barras mostradas tiene una longitud de 1 m y una masa de 2 kg. Ambas giran en el plano horizontal. La barra AB gira con una velocidad angular constante de 4 rad/s en sentido contrario al de las manecillas del reloj. En el instante mostrado, la barra BC gira a 6 rad/s en sentido contrario al de las manecillas del reloj. ¿Cuál es la aceleración angular de la barra BC?


restart; with(VectorCalculus)



m := 2

L := 1

theta := (1/4)*Pi

a[G] = x*alpha[BC]*r[G/B]-omega[BC]^2*r[G/B]+a[B]NULL


a[B] = x*alpha[AB]*r[B/A]-omega[AB]^2*r[B/A]+a[A]


aA := `<,>`(0, 0, 0)

`&alpha;AB` := `<,>`(0, 0, 0)

rBrA := `<,>`(1, 0, 0)

`&omega;AB` := `<,>`(0, 0, 4)

aB := aA+`&x`(`&alpha;AB`, rBrA)-4^2*rBrA

Vector[column](%id = 4411990810)


`&alpha;BC` := `<,>`(0, 0, `&alpha;bc`)

rGrB := `<,>`(.5*cos((1/4)*Pi), -.5*sin((1/4)*Pi), 0)

aG := evalf(aB+`&x`(`&alpha;BC`, rGrB)-6^2*rGrB, 5)

Vector[column](%id = 4412052178)


usando "(&sum;)M[G]=r[BC] x F[xy]"


Fxy := `<,>`(Fx, -Fy, 0)


`&x`(rBC, Fxy) = (1/12*2)*1^2*`&alpha;bc`

(.2500000000*sqrt(2)*(-.70710*`&alpha;bc`-25.456)+(.2500000000*(57.456-.70710*`&alpha;bc`))*sqrt(2))*e[z] = (1/6)*`&alpha;bc`



"(&sum;)Fx:-Fx=m*ax"           y             "(&sum;)Fy:Fy=m*ay"

ax := -28.728+.35355*`&alpha;bc`



ay := .35355*`&alpha;bc`+12.728



Fx := -2*ax



Fy := 2*ay






.2500000000*sqrt(2)*(-.70710*`&alpha;bc`-25.456)+(.2500000000*(57.456-.70710*`&alpha;bc`))*sqrt(2) = (1/6)*`&alpha;bc`

.2500000000*2^(1/2)*(-.70710*`&alpha;bc`-25.456)+(14.36400000-.1767750000*`&alpha;bc`)*2^(1/2) = (1/6)*`&alpha;bc`



[[`&alpha;bc` = 16.97068481]]











# wo is in hertz


# Q is unitless






This is the error message I got:







 Any workaround is appreciated.

Is it possible to solve piecewise differential equations directly instead of separating the pieces and solving them separately.

like for example if i have a two dimensional function f(t,x) whose dynamics is as follows:

dynamics:= piecewise((t,x) in D1, pde1, pde2); where D1 is some region in (t,x)-plane

now is it possible to solve this system with one pde call numerically?

pde(dynamics, boundary conditions, numeric); doesnot work

        i am wording on fluid dynamics, in which i can up a system of nonlinear partial differential equation with i am suppose to solve using implicit keller box method. i need an asistance on how to implement this in maple.


rho := 1.184;
nu := 1.562*10^(-5);
ID := .15;
L := 24.5;
Kl := 12.69;
Ho := 50.52;
a := 2.1*10^(-5);
E := 0.1e-2; alpha := 1.05;








How do I do this??



Hello all,

I have the state-space form of a dynamics sytem:

X_dot = AX+B.U

Y= C X,

The initial conditions of the outputs (Y0) are also given.

A is 7x7 known matrix,

C is 14x7 known matrix,

B = 0;

The problem is that it's too long to write down every equations (14+7 eqns) and variables in "dsolve" function

Would you please show me the shorter way to solve a very large state-space system?

I really appreciate your help.


so ill preface this by saying my knowledge of DE equations is rusty at best and my knowledge of maple even worse so this may be a stupid question. im trying to model the dynamics of a system and when i solve for the DE equation it's giving me an accleration of zero (plotting a blank graph) when it definitely shouldnt be. ive attached the worksheet.


 Sorry for my english, I'm french! :)

I try to make a modelisation of pedestrian dynamics.



There's someone, (a dot in Maple) at some randomn place in a square.


He want to go to another place.

So, there's 3 dot in Maple:

- S: The start fixed

- X: Mr X who is traveling from S to E

- E: The end fixed

so, without any rule, X is drawing a line from S to E.

I have uploaded to the Maplesoft Application Center a worksheet exploring the orbital dynamics of the recently discovered Kepler 16 system, where a planet orbits a double star. 

Your comments and suggestions will be appreciated.


I have simulated as...

1 2 Page 1 of 2