Final Steps in Project

Due 5:00pm, Thursday December 8, 2016. No extensions.
Post Reply
goodwine
Site Admin
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
Contact:

Final Steps in Project

Post by goodwine »

80 points: Modify your program so that
  • for your road (any of the roads, good, average, etc)
  • with specified mass, spring constant and damper constant
your program determines
  • the maximum velocity, v_max, the car can drive down each road such that
    • the suspension does not extend or compress more than 5 cm and
    • the maximum acceleration experienced by the car (either up or down) does not exceed 2 g
  • and with that velocity, what the corresponding maximum force in the damper is.
Limit the velocity range to increments of 10 km/hr between 0 and 140.

NOTE: you probably want to use the max() function in matlab to check that the maximum things are less than the limits. You need to change the code that builds the road! I used variables max and min in the logspace for the wavenos. Either just replace those with the corresponding numbers or change those variable names to maxwaveno and minwaveno. Matlab lets you define variables that are also function names. But if you then try to use the function, it won't let you.

10 more points: Consider
  • the range of spring constants from 1000*9.81 N/m to 12000*9.81 N/m in increments of 1000*9.81 N/m
  • the range of damper values from 0.1*(0.7*2*sqrt(k*m)) to 2.0*(0.7*2*sqrt(k*m)) in increments of 0.2*(0.7*2*sqrt(k*m)).
Of all combinations of k and b from those ranges, which combination maximizes the function

f(k,b,sk0) = 8*v_max - max_damper_force?

This can be for any of the roads.

10 more points: Write a report with the following contents.
  1. Problem Statement: Description of problem you solved.
  2. Methods: Description of approach you used to solve the problem.
  3. Results: What the results were. If there are trends in the trade-offs between k and b and those change for different roads, describe those trends and trade-offs. These may only be underlying your answer, but this may make the report valuable to someone that looks at it in 10 years when the merit function may be different.
  4. Appendix: code printout.
--------------------------------------------------------------------------------------------
10 extra credit points: do the same but for all 5 roads, with merit function

f(k,b) = 8*(v_max_1 + v_max_2 + v_max_3 + v_max_4 + v_max_5) - sum of max_damper_forces

where v_max_i is the max velocity for the various types of road conditions.
Bill Goodwine, 376 Fitzpatrick
rlema

Re: Final Steps in Project

Post by rlema »

Professor, on the first part of this assignment it says that our vehicles shouldn't accelerate past 2 g. However when doing the first part of the design we were told that the acceleration shouldn't exceed the acceleration due to gravity. Which one should we follow?
Brian K

Re: Final Steps in Project

Post by Brian K »

Professor Goodwine, should part II use the max velocity from part I or do we need to calculate a new max v for each spring/damper combination?
goodwine
Site Admin
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
Contact:

Re: Final Steps in Project

Post by goodwine »

rlema wrote:Professor, on the first part of this assignment it says that our vehicles shouldn't accelerate past 2 g. However when doing the first part of the design we were told that the acceleration shouldn't exceed the acceleration due to gravity. Which one should we follow?
Use 2 g now for this part.
Bill Goodwine, 376 Fitzpatrick
goodwine
Site Admin
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
Contact:

Re: Final Steps in Project

Post by goodwine »

Brian K wrote:Professor Goodwine, should part II use the max velocity from part I or do we need to calculate a new max v for each spring/damper combination?
New v_max for each combination.
Bill Goodwine, 376 Fitzpatrick
tduffy1

Re: Final Steps in Project

Post by tduffy1 »

If we were only to finish the first 80% for the final steps of the project, would we receive 80% for the entire project or 80% just for this last part of the project (assuming that all of the 80% is correct)?
goodwine
Site Admin
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
Contact:

Re: Final Steps in Project

Post by goodwine »

tduffy1 wrote:If we were only to finish the first 80% for the final steps of the project, would we receive 80% for the entire project or 80% just for this last part of the project (assuming that all of the 80% is correct)?
The only part that will be graded is this part, so 80% for this part and the whole projects.
Bill Goodwine, 376 Fitzpatrick
mjunker1

Re: Final Steps in Project

Post by mjunker1 »

10 more points: Consider
the range of spring constants from 1000*9.81 N/m to 12000*9.81 N/m in increments of 1000*9/81 N/m
Is the last term here supposed to read "increments of 1000*9.81 N/m" ? As written it is 9/81 N/m
goodwine
Site Admin
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
Contact:

Re: Final Steps in Project

Post by goodwine »

mjunker1 wrote:
10 more points: Consider
the range of spring constants from 1000*9.81 N/m to 12000*9.81 N/m in increments of 1000*9/81 N/m
Is the last term here supposed to read "increments of 1000*9.81 N/m" ? As written it is 9/81 N/m
Yes, that is right. Thanks for pointing it out. I fixed the main post.
Bill Goodwine, 376 Fitzpatrick
pkrog2

Re: Final Steps in Project

Post by pkrog2 »

10 more points: Consider
  • the range of spring constants from 1000*9.81 N/m to 12000*9.81 N/m in increments of 1000*9.81 N/m
  • the range of damper values from 0.1*(0.7*2*sqrt(k*m)) to 2.0*(0.7*2*sqrt(k*m)) in increments of 0.2*(0.7*2*sqrt(k*m)).
For damper values, should we include both ends of the range since technically progressing from 0.1*(0.7*2*sqrt(k*m)) to 2.0*(0.7*2*sqrt(k*m)) in increments of 0.2*(0.7*2*sqrt(k*m)) will result in a final value of 1.9*(0.7*2*sqrt(k*m)) not a value of 2.0(...
goodwine
Site Admin
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
Contact:

Re: Final Steps in Project

Post by goodwine »

pkrog2 wrote:10 more points: Consider
  • the range of spring constants from 1000*9.81 N/m to 12000*9.81 N/m in increments of 1000*9.81 N/m
  • the range of damper values from 0.1*(0.7*2*sqrt(k*m)) to 2.0*(0.7*2*sqrt(k*m)) in increments of 0.2*(0.7*2*sqrt(k*m)).
For damper values, should we include both ends of the range since technically progressing from 0.1*(0.7*2*sqrt(k*m)) to 2.0*(0.7*2*sqrt(k*m)) in increments of 0.2*(0.7*2*sqrt(k*m)) will result in a final value of 1.9*(0.7*2*sqrt(k*m)) not a value of 2.0(...
Whatever you decide is fine on that. Just be clear what your chose.
Bill Goodwine, 376 Fitzpatrick
amuelle1

Re: Final Steps in Project

Post by amuelle1 »

Should the v_max in the merit function be in km/hr or m/s?
goodwine
Site Admin
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
Contact:

Re: Final Steps in Project

Post by goodwine »

amuelle1 wrote:Should the v_max in the merit function be in km/hr or m/s?
I meant for them to be in km/hr but didn't explicitly say so. You don't have to change anything if you finished it with m/s, but if you are making other changes or aren't finished, then please do km/hr
Bill Goodwine, 376 Fitzpatrick
troesler

Re: Final Steps in Project

Post by troesler »

Professor, for our calculation of vertical acceleration, should we incorporate the natural acceleration due to gravity? In other words, should we subtract 9.81 from the second derivative of the vertical position function of the car? This would center the acceleration graph at -9.81 rather than zero.
liliquoywick

Re: Final Steps in Project

Post by liliquoywick »

Are there any length requirements for the report? Also, will we submit our work to you electronically or will we have to print it and deliver it to you?
goodwine
Site Admin
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
Contact:

Re: Final Steps in Project

Post by goodwine »

liliquoywick wrote:Are there any length requirements for the report? Also, will we submit our work to you electronically or will we have to print it and deliver it to you?
There is no minimum or maximum length, but please make an effort to be as concise as possible. Include printed code in your report and email your matlab code to me.
Bill Goodwine, 376 Fitzpatrick
ndigugli

Re: Final Steps in Project

Post by ndigugli »

For the first 10 points, when you ask us to "maximize" the function, does this mean maximize the absolute value? I ask because I'm getting results that might suggest this.
goodwine
Site Admin
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
Contact:

Re: Final Steps in Project

Post by goodwine »

ndigugli wrote:For the first 10 points, when you ask us to "maximize" the function, does this mean maximize the absolute value? I ask because I'm getting results that might suggest this.
No, you don't want large damper forces.
Bill Goodwine, 376 Fitzpatrick
Post Reply

Return to “Project”