## Mode coupling with flexible beams

As a student I came across an amazing lab experimentA T-type structure with two masses attached to it showed a sudden change in oscillation mode.

With MapleSim I was able to reproduce the experiment.

At the time I was told that this perplexing phenome happens because there are always imperfections.

Today we would probably say that the symmetry has to be broken. The attached example has two parameter sets that a) break symmetry of boundary conditions and b) by structural asymmetry (i.e imperfection). Asymmetry in the initial conditions should also be possible (but I could make work with flexible beams).

Compared to coupled oscillators that exchange energy via a coupling spring, this example exchanges energy via masses. In fact in its simplest implementation only one mass and two elastic structures are required for this type of mode coupling. MapleSim multibody library offers plenty of possibilities to demonstrate thisFlexible beams are not required. However, flexible beams show mode coupling beautifully and allow a simple reproduction in real life. For that the worksheet contains a parameter set to build a real model with steel wires. Tuning by adjusting the length of the vertical post is required since nonlinearities already shift frequencies in the model.

I would be interested in other cool examples of mode coupling. I am also interested in solutions for flexible beams that impose asymmetry in the initial conditions. To keep it realistic at the start, the T should be bend as one would bend it with a fingertip in x direction. It would be even more realistic if the arms are flexed by gravity with zero velocity at the start of the simulation. How can this be done?

Flexible_beam_mode_coupling.msim

## Using Python and MapleSim for teaching ODE

This research work demonstrates the use of the MapleSim and Python scientific packages for the correct use of differential equations for engineering students, in the face of the pandemic generated by COVID-19. The main objective is to visualize the teaching and learning process of the subject presented. The methodology used is block diagrams using graphic programming and the one-dimensional symbolic structure. The results are totally optimal since automation was achieved in the differential equations applied to different engineering cases. The applications generated by the scientific software are fully upgradeable and available in the cloud.

Ponencia_CIMAC_2021.pdf

Lenin AC

Using Python and MapleSim versus Basic Science Teaching in Times of Pandemic

Abastract

In the following research work entitled Use of Python and MapleSim against the teaching of Basic Sciences in times of pandemic, due to the social immobility imposed by the government, we saw the need to use scientific software to train our students with modern approaches. The purpose is to raise the learning achievement in the subjects of Mathematics and Physics for engineering. The methodology we used was native syntax programming and graphic component programming. The results that we obtained in modeling and simulation are quite exact, with respect to the traditional results. Finally, all the material can be updated and managed at any time because it is available on maplecloud.

Ponencia_UNTumbes.pdf

Lenin AC

## 3-D Workspace: What does "unlayed out view" mean...

The 3-D Workspace of the stuart platfrom example

displays as follows. Clicking on the central object I get

Q1: What does "Unlayed out view mean"?

Q2: What is actually displayed in the center?

Q3: Why is only one leg shown in instead of 6?

I would really appreciate more insight into the 3-D Workspace. I use it to inspect structural integrity of models and assembly errors, but I am often lost by its behavior.

Thank you!

(I have tried to work it out myself with online resources, Maples help system and MapleSim user guide.)

## I can't find the Thermal Fluid Flow Port in MapleS...

I'm trying to create a custom component in MapleSim 2021, and I want to use Thermal Fluid Flow Ports. However, they don't show up as a type of port in the port Type dropdown.  How can I create a thermal fluid flow port using the Custom Component Template?

## MapleSim 2021 is now available!

We’re excited to announce the release of MapleSim 2021! The MapleSim 2021 family of products lets you build and explore models more easily than ever, with improved simulation performance and 3-D visualizations, new ways to share models with those who don’t use MapleSim, and a host of new and expanded component libraries. Improvements include:

• Improved performance for large models that allows you to take advantage of the fastest simulations yet – no matter how complex your design is.
• More realistic 3-D visualizations with the ability to define dynamic shape sizes, such as spheres and cylinders that expand or contract over the course of the simulation, so components are realistically represented throughout.
• Expanded modeling scope for machine builders, with a new pneumatics component library and expanded hydraulics support, as well as improved visualizations in the MapleSim Ropes and Pulleys Library add-on.
• New simulation and analysis features in MapleSim Insight, a standalone product in the MapleSim family that provides anyone in your organization with access to powerful simulation-based debugging and 3-D visualization capabilities that connect directly to common automation platforms.

## ODE Plotting problem...

Dear Community,

I try to slove a simple 2nd order ODE describing a simple pulley. Unfortunately dsolve does not like what I'm trying to do, and I get en error message. My goal is to plot travel distance, velocity and acceleration (  h(t), dh(t)/dt, d2h(t)/dt2 ) of the lifted weight. Could you pls. have a look what I'm doing wrong?

Also is there a way to transform this worksheet to a MapleSim document somehow? Worksheet attached.

best regards

Andras

SimplePulley.mw

## How to implement normal distributed noise in maple...

Hi

I am trying to implement normally distributed noise into a maplesim simulation. I thought this would be done most easily thru adding a modelica custom component. There are some examples to go on on the web however Modelica are not really good at explaining there implementation.

The code for my implemented block can be seen below.

model Noise2
import MBI = Modelica.Blocks.Interfaces;
import MBN = Modelica.Blocks.Noise;
import MMD = Modelica.Math.Distributions.Uniform;

output MBI.RealOutput out annotation (Placement(transformation(extent={{100,-10},{120,10}})));

inner Modelica.Blocks.Noise.GlobalSeed globalSeed(fixedSeed=42);

MBN.NormalNoise generator(samplePeriod=0.1,distribution=MMD.density(0, -1, 1));

Real y(useGlobalSeed=true, useAutomaticLocalSeed = false, fixedLocalSeed=false, startTime = 0);

equation
out = generator.y;
end Noise2;

However this results in the following error

Argument 1 must have integer[4] data type

Due to my inexperience with Modelica, I don't even know were to start searching for the error. So I turn to this wonderful community in my hour of need, How do I implement normal distributed noise in maplesim?

Mvh

## Changing initial parameters in a FMU created in si...

Hi

I have created a robot ar with p starting position X, Y, Z and a spring that connects to the robot end effector with a spring that is L long. I have exported this simulink model to an FMU inorder to use it in python.

Is it posible to change the value of X, Y, Z and L using pyfmi before using it in pythuon and if it is, then how?

Thanks again for youre time and help. I know that this is not exaclyt inside the expertise of this fine comunity but have no were else to go.

Eric R

## Why do I get "Internal Error" when Angle Sensor fe...

Hi Everyone,

First time asking a question on this website. I am a bit confused about an error I am getting in a pretty straightforward simulation I am trying to generate. It is part of an overall State Machine I am working on but I have isolated the issue to the Angle Sensor and have simplified the issue to ask my question. The issue is as follows:

When simulating the To_Box_5_error.msim file I get the following error

Preparing for integration......
Generating code (derivatives)
(in MapleSim:-CreateDataRecord) internal error occurred during simulation: check console on verbose for more details (5.508s)

This file consits of the angle sensor feeding back to the two <= blocks.

However when simulating the To_Box_5_works.msim file the simulation completes without issue. The difference in the second file is that I feed back the angle sensor value to only one <= block while the second I ijust feed in a constant.

Why would feeding back the same signal to both of these blocks not complete the simulation? The error does not occur for the position sensors that are also in the model.

Any suggestions would be greatly appreciated.

Mike

## Is it possible to create a custom discrete sampled...

I would like to use a template in Maple to create a sampled data custom component to mimic a digital controller in order to study the effects of the non-linear features of the controller.  Is it possible to do this in Maple using a template?

## How to add friction to a joint?...

Hi

I have created an model of a UR5e robot complete with mass and inertia however I have a problem with implementing the viscus friction. I have the viscus friction values for each of the joints calculated from another program, I just need to implement them.

Mvh

Maple 2020.2 includes corrections and improvements to printing and export to PDF, support for macOS 11.0, more MATLAB connectivity, resolves issues with the installation of the Maplesoft Physics Updates, and more.  We recommend that all Maple 2020 users install these updates.

This update is available through Tools>Check for Updates in Maple, and is also available from our website on the Maple 2020.2 download page, where you can also find more details.

## How to best control a maplesim simulation with ext...

Hi

I have constructed a model of an UR5e in maplesim with the hop to be able to test my controller writen in python on it.

I hope to be able from the model to

• Enter a tourqvalue for the joints.
• Extract joint angles, joint velocitys as well as the forces and tourqes that affects the end effector.
• (If posible) visualize the sumulated robot arm so I can se that the motion reflects that of the real robot arm.

the simulated robot arm

The question is how to best do this in a semi realtime way?

I have been looking into generating a FMU but if there are other ways to do this, then I am open to ides.

The contorller is based on a haptic algoritm for connecting two robot arms and I will only get one robot arm due to prise and space constraints.

This means that I will reseave realtime information from the real robot arm into my python controller that then i supose to take inforamtion from the simulated arm and with information from both arms calculate the tourqe values for both arms joints.

Thanks in advance for all youre help

## How to add a second input to a modelica custom com...

Hi

I am trying to implement a maplesim block that takes two vectors as input and a 6x6 matrix as an output. I alrady got help with how to implement the inputs and the outputs however it was for an one input one output system.

The current code is the following

However this results in both inputs being placed ontop of each other

Do anybody know how to change the position of the two inputs so that they are not on top of each other?

Mvh