snaroz
Guest
hello, I own "foundations of mechanics applied to the machines", always of pennestri.
tortellino
Guest
Good.
If you go to the library to tor vergata you also find dynamics of multibody systems (in two volumes) and the book I told you.
If you go to the library to tor vergata you also find dynamics of multibody systems (in two volumes) and the book I told you.
PierArg
Guest
Are you an oracle or part of the secret services? :biggrin:
snaroz
Guest
So, if I understand correctly, should the cinematic couples be 12, come back?
Can someone tell me the model of the car so I can understand how it is done?
Thank you!
Can someone tell me the model of the car so I can understand how it is done?
Thank you!
snaroz
Guest
Can you tell me if what I wrote in post 18 is correct?
Thank you.
Thank you.
cacciatorino
Guest
I apologize for the oct, but I ask you a question:
It seems to me that in the past I talked about scilab as an opensource alternative to mattlab.
If we say I had some time to study, what would you recommend me between freelab and scilab?
p.s. I found this page:
http://amca01.wordpress.com/2011/08/31/the-best-matlab-alternative/
Fulvio Romano
Guest
Remember well. are both very valid.
freemat has a graphical interface made very well, practically cloned by matlab. I suggest it in all cases where code is written. If you have your hand with matlab, go to freemat is painless.
however freemat does not have modules comparable to simulink
scilab has a more osticated interface, although the language is always compact with matlab. then has a module that imitates simulink. has all the main blocks and it is possible to make functional patterns. It's far from using simulink, but if you want a free, well... You can't do too much sketchy. I mean, I recommend scilab every time there's something you'd do with simulink. from my point of view, simulations of control schemes.
the best tool for what has to do snaroz, I think it is freemat.
I don't know him. :frown:
snaroz
Guest
Hi, the problem is I haven't figured out what I have to do yet.
in the meantime I was finishing studying the theory and seeing some exercises carried out that the text proposes me.
returning to the exercise I have to perform, according to the examples I have seen on the book the first thing to do is to represent schematically the right mechanism? What representations do I have to use, that called "polygonal", that of "graphs" or both?
with regard to the calculation of degrees of freedom, do I have to use the formula also known as "formula of grubler"?
then there is one thing that I did not understand on the pdf of the mechanism. the auction called "stunga" to what is it for? to raise the "boom"? and the "tripower" is attached to the "boom" or can it rotate around a certain axis?
thanks to all for the help:finger:
cacciatorino
Guest
I read that freemat should be a "nice message" of octave, but they're just illusions.
However on youtube you will find tutorials on how to start, for example:
http://www.youtube.com/user/diegosendoya
snaroz
Guest
Can no one help me? from the drawing attached to the text I cannot understand the functionality of the various pieces. And then I'm sneaking around with that "stunga"... what do you mean, what's it for?
Good night!
Good night!
Vortexsheet
Guest
a Roman lightning
I tried to install freemat but at the start of the application tells me that there is no mingwm10dll file .. what should I do?
I tried to install freemat but at the start of the application tells me that there is no mingwm10dll file .. what should I do?
Fulvio Romano
Guest
boh... never happened to me. I also use it under windows, and under linux.
I am now under linux... tomorrow I try to see if I find it in a pc windows, and if yes, I send it to you.
snaroz
Guest
Hello, in the count of cinematic pairs should I also consider the hydraulic cylinders?
Fulvio Romano
Guest
I don't know... I honestly thought the doubts were at a higher level of detail. .
I am extremely tempted to put the tip of the pencil on the sheet, but I have to resist.. I'll give you a hand on the low-level labor.
so much to understand what we are talking about, and since obviously neo-engineers have difficulty using the internet, I propose you some interesting readings, found with a quick googular on Sunday afternoon. . .
- to understand what we're talking about:http://forums.dhsdiecast.com/default.aspx?g=posts&m=1084384http://www.ceforum.co.uk/showthread.php?t=226http://www.flickr.com/photos/25804064@n08/2418757111/- and then to say it with Carthium, we are dwarfs, but we have to put on the shoulders of the giants. . .http://www.google.it/url?sa=t&rct=j...1fdpcq&usg=afqjcngeq7aja-obaxs6kzjya6hcwcfhzg
snaroz
Guest
Hello, thank you so much, now at least I can understand how the mechanism is done well!
snaroz
Guest
Hi, can you tell me if what I write now is correct?
the auction "stunga" is hinged for an extreme at the "house", and for the other extreme at the "tripower". Supposing the connections with the two hydraulic cylinders are absent, the "tripower" can rotate around the passing axis for the hinge to which the final end of "stunga" is connected. the "tripower" and the auction "stunga" do not touch the "boom". the latter can rise upwards thanks to the extension of the "boom cylinder"; the stretching action of the "boom cylinder", moreover, puts in rotation the "tripower" around the axis I specified before. In short, the "tripower" is supported by the "stunga", and the tripower+stunga system keeps itself standing thanks to the boom cylinder that is connected to the excavator frame.
the auction "stunga" is hinged for an extreme at the "house", and for the other extreme at the "tripower". Supposing the connections with the two hydraulic cylinders are absent, the "tripower" can rotate around the passing axis for the hinge to which the final end of "stunga" is connected. the "tripower" and the auction "stunga" do not touch the "boom". the latter can rise upwards thanks to the extension of the "boom cylinder"; the stretching action of the "boom cylinder", moreover, puts in rotation the "tripower" around the axis I specified before. In short, the "tripower" is supported by the "stunga", and the tripower+stunga system keeps itself standing thanks to the boom cylinder that is connected to the excavator frame.
snaroz
Guest
hi, then, the members of the mechanism are 18, namely:
1) member frame house;
2) stung;
3) tripower;
4) boom;
5) stick;
6) bucket;
7-8-9-10) the two pieces that make up the stick cilinder, all multiplied by two (there are two stick cilinders)
11-12-13-14) the four pieces of the two boom cylinders;
15-16-17-18) the four pieces of the two bucket roll cylinder.
Is the number of members okay?
First I think I said shit, the tripower can rotate around the boom
1) member frame house;
2) stung;
3) tripower;
4) boom;
5) stick;
6) bucket;
7-8-9-10) the two pieces that make up the stick cilinder, all multiplied by two (there are two stick cilinders)
11-12-13-14) the four pieces of the two boom cylinders;
15-16-17-18) the four pieces of the two bucket roll cylinder.
Is the number of members okay?
First I think I said shit, the tripower can rotate around the boom
Fulvio Romano
Guest
Look, I lost. some things are right, others are wrong, others do not understand. Do I try to explain in my own way?
I follow reasoning as on the drawings:
1. the quadrilateral has three fixed sides and one mobile. How many degrees of residual freedom?
2. the boom moves pushed by b.c. on point a. since h1 and h2 are fixed in space, and since, b and h1 are solidarity with each other, what happens to the quadrilateral of design 1? a, b and h2 have an extra relationship among themselves, how many are now the residual degrees of freedom?
3. s.c. moves the stick compared to the boom
4. br.c. moves the bucket over the tripower.
Can you close the equations?
I don't know exactly what your professor means with "the method of closing equations." So I wouldn't want to put you on a globally just road, but wrong for your exam.
Attachments
Fulvio Romano
Guest
but do the cylinders consider them members? even composed of two pieces? so you don't go out.
Moreover, since it is a flat structure, and it only doubled for static issues, I would study only the two-dimensional structure. otherwise even tripowers are actually two, but so you unnecessarily compliate existence.
I think the purpose is to write a system of equations where you have all system parameters according to the three cylinder lengths. by parameters I mean the angles between the various elements and/or their absolute positions in space.
so you have a cinematic representation.
Then, according to these angles you can solve the static of the system (the stresses) and see how it changes according to the position of the cylinders.
then it would also be nice to do a dynamic analysis, but I think it is clear from the problem. sin not to approach the problem with denavit-hartenberg that arises specifically to do these things...
snaroz
Guest
Thank you. I'll be studying your answer calmly.
As for the three hydraulic cylinders, why don't I consider them as members?
Perhaps because they are motive members and do not add or remove anything from the mechanism itself?
As for the three hydraulic cylinders, why don't I consider them as members?
Perhaps because they are motive members and do not add or remove anything from the mechanism itself?