I was just thinking, when we tested it at your house and it held, we had my thinner, much lighter wheels on it. We weren't testing with the full weight. In addition, that is the maximum they guarantee, it could very well hold a little more, but we are going to be falling in windy conditions that could also add stress.
justin- Do you remeber when we talked about placing "blocks" in between the wheel and the hardware? I'm thinking along the line of an eraser or something like a sponge to absorb the shock of the parachute deploying. I think that plus a larger washer will be give the ASP-Bot 100% working percentage and allow it to not release mid-flight.
How is that larger washer working?
All- I've heard that the coming practice may be an issue for a few poeple? Because we are running out of time we need to continue with the work at some time, even if it is not sunday. Any proposed ideas of when and where to meet?
justin- Do you remeber when we talked about placing "blocks" in between the wheel and the hardware? I'm thinking along the line of an eraser or something like a sponge to absorb the shock of the parachute deploying. I think that plus a larger washer will be give the ASP-Bot 100% working percentage and allow it to not release mid-flight.
How is that larger washer working?
All- I've heard that the coming practice may be an issue for a few poeple? Because we are running out of time we need to continue with the work at some time, even if it is not sunday. Any proposed ideas of when and where to meet?
Thanks again,
-Jake-
NEXT PRACTICE is Monday, May 30th from 2-5 PM.
1) The Goffstown Rotary presentation is the very next day and we begin speaking at 7:30 AM.
2) Our field trip to the University of New Hampshire (a tour of the facilities and the Space Grant conference) is the same Thursady, June 2nd. We'll leave at 8 AM to be there by 9 AM for a tour.
Sorry for my absence, there was a random increase in the homework load and I had to take care of that first.
2) Our field trip to the University of New Hampshire (a tour of the facilities and the Space Grant conference) is the same Thursady, June 2nd. We'll leave at 8 AM to be there by 9 AM for a tour.
Could I have some more info on this tour? I understand that we are to create a tri-fold poster, but I am unsure of what exactly we are going to be doing with it, as well as its purposes. I feel like some more information is needed to be able to take our first steps towards per preparing for this event.
Sorry for my absence, there was a random increase in the homework load and I had to take care of that first.
Could I have some more info on this tour? I understand that we are to create a tri-fold poster, but I am unsure of what exactly we are going to be doing with it, as well as its purposes. I feel like some more information is needed to be able to take our first steps towards per preparing for this event.
We're setting up a display table at the Space Grant Conference at the University of New Hampshire. It includes a three-panel "science fair" display that explains our ARLISS project in pictures and in words. It needs to look very professional (printed letters, color photos, no magic markers) because this is a professional conference. We'll set up two laptops and have the PowerPoint presentation and the video running and we need to have at least two people at the table from 12-3 PM. We'l also bring the rover, the ASP, rockets, and handouts.
Check with Andrew for more details because we had to make a similar display for NASA when we went to Marshall Space Flight Center a few years ago. Here are the details from UNH:
"A proclamation from Governor John Lynch declares Thursday June 2nd, 2011 to be New Hampshire Space Grant Day. Join members of the NH Space Grant Consortium, officials from UNH and NASA - including keynote speaker former NASA Astronaut Jeff Hoffman - in celebrating 20 years of dedicated work in improving education and public awareness of science, engineering, and mathematics, particularly as they relate to our nation's space program.
From 12-3 in Morse Hall at the University of New Hampshire, in Durham, in addition to astronaut Hoffman's presentation on "the Future of Human Spaceflight", there will be exhibits and demonstrations centered on student-built rovers, robots, rocketry and satellite projects, research posters, solar observing and a planetarium show: The Earth's Wild Ride. There will also be tours of EOS facilities, including the Space Science Center's machine shop where UNH-built instruments for NASA science missions are fabricated, and the Geospatial Information Systems and Remote Sensing Lab.
Keynote Speaker Jeff Hoffman is the current director of the Massachusetts Space Grant Consortium and a professor of the Practice of Aerospace Engineering in the Department of Aeronautics and Astronautics at the Massachusetts Institute of Technology. As a NASA Space Shuttle astronaut he made five flights and performed four spacewalks, including the first unplanned, contingency spacewalk in NASA's history and the initial repair/rescue mission of the Hubble Telescope.
Parents are welcome to join us for an afternoon of celebrating.
For further details, directions and parking information visit:
I need to ask for some programming help. Jake and I have tested the single eyebolt parachute release mechanism. The thing is that we tested it with the wheel going slower. In the programming I changed the PULSOUT values to 720 and 780 using the Basic Stamp to control the servos directly. The problem with that is, to impliment the release mechanism onto the rover the servo would need to be programmed to run at the same speed as the tests. With the ServoPal, you use PULSIN values which are 500 and 1000 for full speed backwards and fowards. I guess what I am asking is how to translate the Basic Stamp PULSOUT commands to the ServoPal PULSIN commands.
PJ and Sylvie - Any help would be greatly appreciated.
I met with Mr. Kibler and Jake today at school. We ran seventy-five tests on my prototype using the single eyebolt and it worked 100%. After the testing, Mr. Kibler and I were talking and agreed that it would be benefitial for the rover to move foward slowly and then backwards slowly and then to accelerate to full speed. The purpouse of this is that if while the parachute eyebolt is being released the parachute cords tangle around the wheel, moving it backwards would untangle them and then the rover would be able to manuever. Tomorrow I will be going back for further testing. One additional test that we are planning to do in the very near future is a "drop test" using the prototype. We want to drop it from the bleachers, without the electronics, but with the servos to see if the servo axle can take the strain of being dropped. Please post the revised program and e-mail it to both me and Mr. Kibler to test. Keep in mind that you are programming with the PULSIN 500 and 1000 values instead of the PULSOUT 650 and 850.
Justin,
Who exactly are you asking for the program? The program design team, or is this a team wide assignment? Or possibly something for Sylvie and PJ.
Justin,
Who exactly are you asking for the program? The program design team, or is this a team wide assignment? Or possibly something for Sylvie and PJ.
Dylan,
The programming task is for you and Andrew specifically, and more generally for anyone you can recruit to help you. You might want to write the progarm code first, upload it so I can try it out, then see how much help we do or don't need. I think you and Andrew can handle it but we do need the program sooner rather than later so that Justin and Jake and I can finish running tests on the parachute release mechanism in the lab at school. I'd like to get the program and the tests wrapped up by Friday at the latest.
Justin,
I thought you were trying to move the servos using the servoPal. To jiggle the rover back and forth to prevent tangling between the rover and parachute lines.
Jake,
As far as I know the BeeLine procedure was to be done by last practice, but I haven't heard word of where it is currently at on being completed.
Mr. Kibler,
Could you email or post the latest version we have of the master program to the forum?
Hi all- I'm curious to know how the procedure is coming along. Is someone working on that or should I start on it? If so, where should I start?
Justin- What did you accomplish after I left for Social Studies? did the Apoxy harden?
Thanks again,
-Jake-
Hi Everyone,
Jake - After you left the epoxy did harden, and I got in one hundred tests. We had a 100% success rate and are planning a drop test in the cafeteria.
I am glad you asked about the procedures. I was just going to ask which ones we had and where they were. What procedures are there that are not written. Mr. Kibler and I are planning to meet at 11:00 at school Thursday to write as many as we can of the remaining procedures. Basically, I'm going to have a computer and have him give me a "brain dump." Jake do you want to join us? I need to know which ones are yet to be written and which ones are started but only partially done. I think some were done in years prior that just need to be tweaked. Can you let me know where those are too? Please post this list.
Dylan-I was not attempting to move the servos using my basic stamp. I need you and Andrew to figure out how to translate the PULSOUT values of the basic stamp to the PULSIN values of the ServoPal.
Is there anything that those of you working on the presentation need me to bring Monday?
Justin,
Ok, I understand. Once Andrew and I are able to talk we will approach the programming problem.
I have just been busy lately because I have a Research paper, Speech and Model UN Practice all occurring on the same week in the next few days that I have to work on.
I have just (semi) finished the program that incorporates a beginning "wiggle" to shake loose the release mechanism and prevent tangling.
The program should (in logical terms) be able to do so, although, I am getting an "IF without ENDIF" error. Mr. Kibler and Andrew have seen these before, since it is a very basic error. But, here comes in the tricky part.. I followed how you should write it, and have seen it written in the exact same manner in the program, but for whatever reason, keep getting this error. It seems as if it shouldn't be reoccurring like this, but still is. I have honestly never been this baffled at such a basic error haha. I was hoping that you Mr. Kibler, Sylvie, P.J or Andrew would catch what mistake I am making. (All the changes are towards the very bottom of the program)
I need to know where I can help.
1. How is the presentation and poster coming along. When you come Monday where will it be. If you could post pictures or descriptions of your progress that would be really helpful. If you need me to do anything I will have some time over the weekend to help.
2. Where are all of the procedures. I want to start putting all of the completed procedures into a binder.
Mr. Kibler and I have a question for you. If you have read the last few pages of the forum you would know that we are working on a new parachute release mechanism. We need some way of testing if the axle of the servo will break if we put the strain of the rover on it, or more importantly, when the strain of the parachute is opened. I was hoping that you could give us some ideas on how to do that accuratly to replicate the strains of the rover coming out of the rocket. The rover will be coming out of the rocket with the parachute and payload right side up. Given that the rover weighs 1684 grams and we have the wheel suspended by a single eye-bolt attached to the wheel and the wheel only attached by a single servo to the rest of the body of the rover, what are the stresses that we are dealing with on that one axle. Our main fear is that the axle will break under the strain of the opening of the parachute. How would we calculate how much force that axle could stand. Would the size of the parachute or the length of the shock cord be significant numbers in that equasion.
So we're back to square 1 with the release mechanism or is it just a variation of the one we had Justin? Or is the one you were working last meeting? We really need to get a working release mechanism before we leave for black rock. I mean nobody wants to see our rover become a large splat of parts on the desert. Emily, Andrew, and I will continue working on the trifold display over the weekend. Hopefully.
See ya all soon,
Obie
This is where we are on the parachute release mechanism. Mr. Kibler wanted us to test the mechanism and not work on alternatives so we could get the eyebolt completely tested and configured. It works very well, but there has always been a concern that the single axle could break, and thus have everything crash. Mr. Kibler went ahead and put the groove for the eyebolt in the final rover. So, where we sit as of today, is we will either go with the eyebolt, or we will simply bolt the parachute on to the rover itself and have it drag the parachute. At this point, there were some other possible solutions. I had a single bolt going across the two wheels that was further refined after the shortwave transmitter placement affected my previous design. There was also the idea of Chase. The bottom line, however, at this point, is that there just isn't a lot of time to test anything else and the rover has the grooves already in the wheel. We could make more issues going with a new idea at this point. The team as a whole, will need to decide on whether we go ahead with the eyebolt or just hook the parachute on the body. What I have been asked to do, however, so that we can make a good decision, is to come up with a confidence level of the axle holding out during the drop. THAT is what I need help doing. I'm not sure how best to replicate what will happen out of the rocket and simulate that force to see whether the axle can withstand it.
I have just (semi) finished the program that incorporates a beginning "wiggle" to shake loose the release mechanism and prevent tangling.
The program should (in logical terms) be able to do so, although, I am getting an "IF without ENDIF" error. Mr. Kibler and Andrew have seen these before, since it is a very basic error. But, here comes in the tricky part.. I followed how you should write it, and have seen it written in the exact same manner in the program, but for whatever reason, keep getting this error. It seems as if it shouldn't be reoccurring like this, but still is. I have honestly never been this baffled at such a basic error haha. I was hoping that you Mr. Kibler, Sylvie, P.J or Andrew would catch what mistake I am making. (All the changes are towards the very bottom of the program)
You have this:
wigglesub:
wiggle = wiggle +1 MAX 3
IF wiggle = 1 THEN
PULSOUT nInp, 500
PULSOUT nInp, 1000
IF wiggle = 2 THEN
PULSOUT nInp, 1000
PULSOUT nInp, 500
IF wiggle = 3 THEN
GOSUB Movement
RETURN
The situation cries out for a "SELECT CASE" statement instead:
wigglesub:
wiggle = wiggle +1 MAX 3
SELECT wiggle
CASE 1
PULSOUT nInp, 500
PULSOUT nInp, 1000
CASE 2
PULSOUT nInp, 1000
PULSOUT nInp, 500
CASE 3
GOSUB Movement
ENDSELECT
RETURN
(try it, and see if it does what you want)
Read the help file about SELECT CASE. It's an alternative branching command, one that you use when you want to do one of several actions depending upon the state of a variable.
You're getting the IF without ENDIF error because, of course, you have no ENDIF to tell the program how much of the code to execute under each IF condition. It's possible to put in the ENDIFs, but you'll have a mess. The SELECT CASE is much neater. You know that the variable wiggle has one of three values. If it enters your code with the value 1, it will do the first set of PULSOUT statements, then go check if wiggle = 2, and since it does not, it will go off into never never land since there is nothing to do if wiggle does not equal 2. If you go into the code with wiggle = 2, it will reach the IF wiggle = 1 code, and since it does not, it will immediately go into never never land.
You indented the code nicely to indicate what you wanted, but the PBASIC compiler doesn't care at all about indentation. The indents are great coding practice, but in PBASIC you need to explicitly tell the compiler what to do. As an aside, there ARE programming environments in which the indentation DOES tell the compiler how much of your code belongs within an IF statement (or its equivalent). For the most immediate example, the Parallax SPIN language compiler (used with the Propeller chip) does exactly that.
You could find out something about the force by "testing to failure", if you had a spare setup of your device. You'd just put a strain gauge (okay, fish scale) into the loop, and pull until the axle broke. But you wouldn't really learn what you need to know, because there are so many other variables, notably the suddenness with which the force is applied, plus you don't know the actual force that you'll encounter in flight.
There are things you can do instead to minimize the danger. A long shock cord does help, because the energy from the parachute opening is somewhat dissipated as it straightens out the shock cord. You can increase the amount of energy put into that by accordian folding the shock cord and holding it in place with rubber bands.
Did we talk about deployment bags a year or two ago? You can put the parachute into a deployment bag, which prevents it from opening until the lines are all extended fully. This reduces the sudden snap of the chute's opening. The deployment bag is connected to a small pilot chute, which pulls everything straight, and then pulls the bag off of the main parachute.
I really like the idea of having the deploy bag! If we place some sort of "block" in-between the wheels, and then with those two combined, we should be able to pull the ASP-bot out of the payload safely and intact. I suggest we use "blocks on both sides of the wheels as well to create a smoother landing. I think the block should be made out of some sort of gel substance, like the surgical tubing but in a block shape.
Mr. Kibler- Were you being serious about the singing the UNH song??? If so, what is the name of the song so I can find it. Would it be a Solo or would I be leading it?
2. I also really like the idea of having a deployment bag and folding up the shock cord with rubber bands. Do any of you have any experience with using a deployment bag
3. I think that pulling on the servo and recording how much tenion it would handle would be a beneficial test. If the rover weighs about 3.7 pounds and it breaks at 4 pounds, that would be a fairly good indication that this would be an issue well worth looking into.
4. Mr. Kibler - I have found an area in my house that I can do some testing. I could do some preliminary testing out of my houses third story attic window. It looks as if it is about 30 feet up and it is a clear shot to the ground.
5. Jake - In the past we have talked about using gum erasers between the wheels. Would that be the same type of consistency that you are looking for. Is there something that you think would be better to absorb the shock.
Sylvie,
Thank you very much for you explanation. I understand programming in more of a logical way then technical, and that helped a LOT in the way you described it. I do believe that will fix it, but I will have to wait until Mr. Kibler has the convenience of testing it inside of his gas chamber.
I also like the Idea of the bag, and/or a longer shock cord. In combination, the initial forces exerted by the parachute to minimal numbers than originally.
Comments
How is that larger washer working?
All- I've heard that the coming practice may be an issue for a few poeple? Because we are running out of time we need to continue with the work at some time, even if it is not sunday. Any proposed ideas of when and where to meet?
Thanks again,
-Jake-
NEXT PRACTICE is Monday, May 30th from 2-5 PM.
1) The Goffstown Rotary presentation is the very next day and we begin speaking at 7:30 AM.
2) Our field trip to the University of New Hampshire (a tour of the facilities and the Space Grant conference) is the same Thursady, June 2nd. We'll leave at 8 AM to be there by 9 AM for a tour.
Please mark these dats on your calendar.
Thanks,
Mr. Kibler
:cool:
Could I have some more info on this tour? I understand that we are to create a tri-fold poster, but I am unsure of what exactly we are going to be doing with it, as well as its purposes. I feel like some more information is needed to be able to take our first steps towards per preparing for this event.
We're setting up a display table at the Space Grant Conference at the University of New Hampshire. It includes a three-panel "science fair" display that explains our ARLISS project in pictures and in words. It needs to look very professional (printed letters, color photos, no magic markers) because this is a professional conference. We'll set up two laptops and have the PowerPoint presentation and the video running and we need to have at least two people at the table from 12-3 PM. We'l also bring the rover, the ASP, rockets, and handouts.
Check with Andrew for more details because we had to make a similar display for NASA when we went to Marshall Space Flight Center a few years ago. Here are the details from UNH:
"A proclamation from Governor John Lynch declares Thursday June 2nd, 2011 to be New Hampshire Space Grant Day. Join members of the NH Space Grant Consortium, officials from UNH and NASA - including keynote speaker former NASA Astronaut Jeff Hoffman - in celebrating 20 years of dedicated work in improving education and public awareness of science, engineering, and mathematics, particularly as they relate to our nation's space program.
From 12-3 in Morse Hall at the University of New Hampshire, in Durham, in addition to astronaut Hoffman's presentation on "the Future of Human Spaceflight", there will be exhibits and demonstrations centered on student-built rovers, robots, rocketry and satellite projects, research posters, solar observing and a planetarium show: The Earth's Wild Ride. There will also be tours of EOS facilities, including the Space Science Center's machine shop where UNH-built instruments for NASA science missions are fabricated, and the Geospatial Information Systems and Remote Sensing Lab.
Keynote Speaker Jeff Hoffman is the current director of the Massachusetts Space Grant Consortium and a professor of the Practice of Aerospace Engineering in the Department of Aeronautics and Astronautics at the Massachusetts Institute of Technology. As a NASA Space Shuttle astronaut he made five flights and performed four spacewalks, including the first unplanned, contingency spacewalk in NASA's history and the initial repair/rescue mission of the Hubble Telescope.
Parents are welcome to join us for an afternoon of celebrating.
For further details, directions and parking information visit:
http://www.nhsgc.sr.unh.edu/20years.html
Mr. Kibler
:cool:
I need to ask for some programming help. Jake and I have tested the single eyebolt parachute release mechanism. The thing is that we tested it with the wheel going slower. In the programming I changed the PULSOUT values to 720 and 780 using the Basic Stamp to control the servos directly. The problem with that is, to impliment the release mechanism onto the rover the servo would need to be programmed to run at the same speed as the tests. With the ServoPal, you use PULSIN values which are 500 and 1000 for full speed backwards and fowards. I guess what I am asking is how to translate the Basic Stamp PULSOUT commands to the ServoPal PULSIN commands.
PJ and Sylvie - Any help would be greatly appreciated.
Justin
I met with Mr. Kibler and Jake today at school. We ran seventy-five tests on my prototype using the single eyebolt and it worked 100%. After the testing, Mr. Kibler and I were talking and agreed that it would be benefitial for the rover to move foward slowly and then backwards slowly and then to accelerate to full speed. The purpouse of this is that if while the parachute eyebolt is being released the parachute cords tangle around the wheel, moving it backwards would untangle them and then the rover would be able to manuever. Tomorrow I will be going back for further testing. One additional test that we are planning to do in the very near future is a "drop test" using the prototype. We want to drop it from the bleachers, without the electronics, but with the servos to see if the servo axle can take the strain of being dropped. Please post the revised program and e-mail it to both me and Mr. Kibler to test. Keep in mind that you are programming with the PULSIN 500 and 1000 values instead of the PULSOUT 650 and 850.
Thanks!
Justin
Who exactly are you asking for the program? The program design team, or is this a team wide assignment? Or possibly something for Sylvie and PJ.
Dylan,
The programming task is for you and Andrew specifically, and more generally for anyone you can recruit to help you. You might want to write the progarm code first, upload it so I can try it out, then see how much help we do or don't need. I think you and Andrew can handle it but we do need the program sooner rather than later so that Justin and Jake and I can finish running tests on the parachute release mechanism in the lab at school. I'd like to get the program and the tests wrapped up by Friday at the latest.
M
r.
K
i
b
l
e
r
:cool:
Jake and Justin,
Could you upload the program you attempted at editing?
I did not edit any program. I just wrote a new program to work with a pushbutton.
Justin
Justin- What did you accomplish after I left for Social Studies? did the Apoxy harden?
Thanks again,
-Jake-
I thought you were trying to move the servos using the servoPal. To jiggle the rover back and forth to prevent tangling between the rover and parachute lines.
Jake,
As far as I know the BeeLine procedure was to be done by last practice, but I haven't heard word of where it is currently at on being completed.
Mr. Kibler,
Could you email or post the latest version we have of the master program to the forum?
Hi Everyone,
Jake - After you left the epoxy did harden, and I got in one hundred tests. We had a 100% success rate and are planning a drop test in the cafeteria.
I am glad you asked about the procedures. I was just going to ask which ones we had and where they were. What procedures are there that are not written. Mr. Kibler and I are planning to meet at 11:00 at school Thursday to write as many as we can of the remaining procedures. Basically, I'm going to have a computer and have him give me a "brain dump." Jake do you want to join us? I need to know which ones are yet to be written and which ones are started but only partially done. I think some were done in years prior that just need to be tweaked. Can you let me know where those are too? Please post this list.
Dylan-I was not attempting to move the servos using my basic stamp. I need you and Andrew to figure out how to translate the PULSOUT values of the basic stamp to the PULSIN values of the ServoPal.
Is there anything that those of you working on the presentation need me to bring Monday?
Justin
Ok, I understand. Once Andrew and I are able to talk we will approach the programming problem.
I have just been busy lately because I have a Research paper, Speech and Model UN Practice all occurring on the same week in the next few days that I have to work on.
I have the Beeline procedure and it is edited and almost complete, It just needs to be read through by someone else.
Emily
Auntie Em,
Can you post the procedure to the forum so we can all download it and read through it?
Thanks,
Wizard of Oz Kibler
:cool:
A drop test in the Cafeteria... When will we have the Cafe to ourselves to carry out a test like that? Just curious!
Thanks Again,
-Jake-
I have just (semi) finished the program that incorporates a beginning "wiggle" to shake loose the release mechanism and prevent tangling.
The program should (in logical terms) be able to do so, although, I am getting an "IF without ENDIF" error. Mr. Kibler and Andrew have seen these before, since it is a very basic error. But, here comes in the tricky part.. I followed how you should write it, and have seen it written in the exact same manner in the program, but for whatever reason, keep getting this error. It seems as if it shouldn't be reoccurring like this, but still is. I have honestly never been this baffled at such a basic error haha. I was hoping that you Mr. Kibler, Sylvie, P.J or Andrew would catch what mistake I am making. (All the changes are towards the very bottom of the program)
I need to know where I can help.
1. How is the presentation and poster coming along. When you come Monday where will it be. If you could post pictures or descriptions of your progress that would be really helpful. If you need me to do anything I will have some time over the weekend to help.
2. Where are all of the procedures. I want to start putting all of the completed procedures into a binder.
I just want to know where to help.
Justin
This question is more for Sylvie and PJ Allen.
Mr. Kibler and I have a question for you. If you have read the last few pages of the forum you would know that we are working on a new parachute release mechanism. We need some way of testing if the axle of the servo will break if we put the strain of the rover on it, or more importantly, when the strain of the parachute is opened. I was hoping that you could give us some ideas on how to do that accuratly to replicate the strains of the rover coming out of the rocket. The rover will be coming out of the rocket with the parachute and payload right side up. Given that the rover weighs 1684 grams and we have the wheel suspended by a single eye-bolt attached to the wheel and the wheel only attached by a single servo to the rest of the body of the rover, what are the stresses that we are dealing with on that one axle. Our main fear is that the axle will break under the strain of the opening of the parachute. How would we calculate how much force that axle could stand. Would the size of the parachute or the length of the shock cord be significant numbers in that equasion.
Any help would be greatly appreciated.
Justin
See ya all soon,
Obie
This is where we are on the parachute release mechanism. Mr. Kibler wanted us to test the mechanism and not work on alternatives so we could get the eyebolt completely tested and configured. It works very well, but there has always been a concern that the single axle could break, and thus have everything crash. Mr. Kibler went ahead and put the groove for the eyebolt in the final rover. So, where we sit as of today, is we will either go with the eyebolt, or we will simply bolt the parachute on to the rover itself and have it drag the parachute. At this point, there were some other possible solutions. I had a single bolt going across the two wheels that was further refined after the shortwave transmitter placement affected my previous design. There was also the idea of Chase. The bottom line, however, at this point, is that there just isn't a lot of time to test anything else and the rover has the grooves already in the wheel. We could make more issues going with a new idea at this point. The team as a whole, will need to decide on whether we go ahead with the eyebolt or just hook the parachute on the body. What I have been asked to do, however, so that we can make a good decision, is to come up with a confidence level of the axle holding out during the drop. THAT is what I need help doing. I'm not sure how best to replicate what will happen out of the rocket and simulate that force to see whether the axle can withstand it.
Justin
You have this:
The situation cries out for a "SELECT CASE" statement instead:
(try it, and see if it does what you want)
Read the help file about SELECT CASE. It's an alternative branching command, one that you use when you want to do one of several actions depending upon the state of a variable.
You're getting the IF without ENDIF error because, of course, you have no ENDIF to tell the program how much of the code to execute under each IF condition. It's possible to put in the ENDIFs, but you'll have a mess. The SELECT CASE is much neater. You know that the variable wiggle has one of three values. If it enters your code with the value 1, it will do the first set of PULSOUT statements, then go check if wiggle = 2, and since it does not, it will go off into never never land since there is nothing to do if wiggle does not equal 2. If you go into the code with wiggle = 2, it will reach the IF wiggle = 1 code, and since it does not, it will immediately go into never never land.
You indented the code nicely to indicate what you wanted, but the PBASIC compiler doesn't care at all about indentation. The indents are great coding practice, but in PBASIC you need to explicitly tell the compiler what to do. As an aside, there ARE programming environments in which the indentation DOES tell the compiler how much of your code belongs within an IF statement (or its equivalent). For the most immediate example, the Parallax SPIN language compiler (used with the Propeller chip) does exactly that.
You could find out something about the force by "testing to failure", if you had a spare setup of your device. You'd just put a strain gauge (okay, fish scale) into the loop, and pull until the axle broke. But you wouldn't really learn what you need to know, because there are so many other variables, notably the suddenness with which the force is applied, plus you don't know the actual force that you'll encounter in flight.
There are things you can do instead to minimize the danger. A long shock cord does help, because the energy from the parachute opening is somewhat dissipated as it straightens out the shock cord. You can increase the amount of energy put into that by accordian folding the shock cord and holding it in place with rubber bands.
Did we talk about deployment bags a year or two ago? You can put the parachute into a deployment bag, which prevents it from opening until the lines are all extended fully. This reduces the sudden snap of the chute's opening. The deployment bag is connected to a small pilot chute, which pulls everything straight, and then pulls the bag off of the main parachute.
Thanks again,
-Jake-
I have a few things to talk about in this post.
1. Thank you Sylvie for the help on both issues.
2. I also really like the idea of having a deployment bag and folding up the shock cord with rubber bands. Do any of you have any experience with using a deployment bag
3. I think that pulling on the servo and recording how much tenion it would handle would be a beneficial test. If the rover weighs about 3.7 pounds and it breaks at 4 pounds, that would be a fairly good indication that this would be an issue well worth looking into.
4. Mr. Kibler - I have found an area in my house that I can do some testing. I could do some preliminary testing out of my houses third story attic window. It looks as if it is about 30 feet up and it is a clear shot to the ground.
5. Jake - In the past we have talked about using gum erasers between the wheels. Would that be the same type of consistency that you are looking for. Is there something that you think would be better to absorb the shock.
Justin
Thank you very much for you explanation. I understand programming in more of a logical way then technical, and that helped a LOT in the way you described it. I do believe that will fix it, but I will have to wait until Mr. Kibler has the convenience of testing it inside of his gas chamber.
I also like the Idea of the bag, and/or a longer shock cord. In combination, the initial forces exerted by the parachute to minimal numbers than originally.