Discussion in 'The Projects Forum' started by agustrush, Nov 17, 2008.

1. ### agustrush Thread Starter New Member

Nov 17, 2008
3
0
Hi, you~ I am new here, glad to meet you all.

I am doing a project on designing a math model for freight elevator. The model is about the motion of a heavy-duty freight elevator used to raise and lower equipment and minerals in a mineshaft. I got an example from my professor, and I need to evaluate his model for its strengths and weakness, and then create a new one which can improve his weakness as much as possible.

Here is the example: The formula y=2.5t3-15t2 represents the position of the elevator, y, measured in meters (y=0 represents ground level) and t represents time measured in minutes (t=0 is the starting time). We know that the trip up and down the shaft, ignoring time spent at the foot of the shaft, is approximately six minutes and that the depth of the shaft is no more than 100 meters.

For the math model, we can use a single function or combine functions in a piecewise function.

I really need you help, please! Thanks!!! Here is my e-mail address: willpapa@sohu.com and you can also join me in MSN: agustrush0320@hotmail.com

2. ### floomdoggle Senior Member

Sep 1, 2008
217
2
A little more explanation of your experiment would be nice. Most up-down forces can be worked out by your finger. The pressure of certain muscles are more accurate than any meter or equation.
Dan

3. ### scubasteve_911 Senior Member

Dec 27, 2007
1,202
1
That is hardly a mathematical model, it is an expression for position. Mathematical models imply a stimulus or input signal and dictate the system's response to that input. Basically, you're 'model' is a system whos only input is time.

I will wait until you respond, considering your contact information was given. We don't offer help through email or PM, just on the forum so that others can learn. Unless you want to pay me 50\$ an hour...

Steve

4. ### agustrush Thread Starter New Member

Nov 17, 2008
3
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thanks a lot!!! well, actully mine is not an experiment, just a math portfolio, I think there may be some misunderstanding about my project. I am going to figure out the displacement, velocity and acceleration graphs for the freight elevator against the time by doing the derivative. (By the way, I am a Chinese high school student, so my English is not so good, I hope you don't mind if there is any problems with my language.)

5. ### agustrush Thread Starter New Member

Nov 17, 2008
3
0
thanks a lot!!! well, I'd like to discuss on the forum. (I don't have extra money for paying this math project since I need to do several in a year) except the expression for position, I also need the velocity and acceleration too. when you mention input signal, do you mean that I need to do this project by computer? like to create a programme to show the project?

6. ### pitso New Member

Dec 2, 2008
1
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hi! im also doing this portfolio and it is due this friday.

7. ### farnhamk New Member

Dec 13, 2008
1
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Agustrush,
I'm doing this portfolio also. Please don't take any offense to me but, have you derived the equation? If not, you need to do so twice because you are given the position and need to find the velocity, y', and acceleration, y". I bet you already did that, sorry if I just told you stuff you already knew.
You may want to graph this data. I found graphcalc most invaluable. It's free and easy to understand. It is also a great way to check you work.
I am having problems, also. I forgot how to interprete the information from the graphs and I need to figure out how to make a better mathematical representation.
I would post my findings, but I'm not sure how or if that is academically sound since it an Internal Assessment, for me anyway.
I hope I helped.
If anyone could direct me to a site has elevator schematics, I would be forever in your debt.
Thank you.

8. ### floomdoggle Senior Member

Sep 1, 2008
217
2
Try looking up Otis elevators.
Dan