Go to Post Everybody "cares about the robots" - otherwise we'd be doing science fairs. - Taylor [more]
Home
Go Back   Chief Delphi > FIRST > General Forum
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
Thread Tools Rating: Thread Rating: 3 votes, 5.00 average. Display Modes
  #16   Spotlight this post!  
Unread 13-02-2014, 15:26
Andrew Schreiber Andrew Schreiber is offline
Joining the 900 Meme Team
FRC #0079
 
Join Date: Jan 2005
Rookie Year: 2000
Location: Misplaced Michigander
Posts: 4,074
Andrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by Jon Stratis View Post
Have you ever seen a fool-proof mechanism or sensor on a FIRST robot? I know I haven't... It would take quite a bit for a team to convince me that whatever system they have in place to prevent a dry fire isn't going to break at some point during the competition and allow the system to dry fire anyways. We've all seen some crazy stuff happen to a robot that no one expected...
Next thing you'll be asking me to demonstrate that my gearbox properly constrains parts if I break my gears...

We'll have a system in place to bypass any safety systems we end up with.


I'd hoped to clarify under what circumstances dry firing will be needed. I just don't like being told "oh, it depends on how your inspector feels" because I'd like to think that all robots are inspected equally and fairly and an inspector can't cause undue wear and tear on a mechanism/stress on a team merely because they feel like it.
__________________




.
Reply With Quote
  #17   Spotlight this post!  
Unread 13-02-2014, 15:28
BigJ BigJ is offline
Registered User
AKA: Josh P.
FRC #1675 (Ultimate Protection Squad)
Team Role: Engineer
 
Join Date: Jan 2007
Rookie Year: 2007
Location: Milwaukee, WI
Posts: 947
BigJ has a reputation beyond reputeBigJ has a reputation beyond reputeBigJ has a reputation beyond reputeBigJ has a reputation beyond reputeBigJ has a reputation beyond reputeBigJ has a reputation beyond reputeBigJ has a reputation beyond reputeBigJ has a reputation beyond reputeBigJ has a reputation beyond reputeBigJ has a reputation beyond reputeBigJ has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by magnets View Post
I agree, there are no robots out there that are perfect.
You're saying that inspectors need to make sure that when the robot malfunctions, it's safe.

So, let's look at another malfunction. If my robot were to try to fire a ball as the intake was stowed, I'd break my intake. Does the inspector need to watch me break my robot that way too?

However, dry firing my shooter will break it, but pose no safety hazard.

This whole test is a bit stupid. It's kind of like asking teams to drop their robots from the top of the pyramid to make sure that when it falls, it isn't dangerous.
The difference is that a robot on the pyramid has a large amount of potential energy that could end up directed as kinetic energy towards the ground (or maybe onto another robot), where a spring or winch on the robot stores a lot of potential energy that is many times directed upwards and at an angle, which could potentially go towards any number of volunteers, human players, or audience members.
Reply With Quote
  #18   Spotlight this post!  
Unread 13-02-2014, 15:30
magnets's Avatar
magnets magnets is offline
Registered User
no team
 
Join Date: Jun 2013
Rookie Year: 2012
Location: United States
Posts: 748
magnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by jvriezen View Post
So what I think Al and Jon are saying is that you should (and RI's will) assume the worst case that your robot will dry fire at some point unexpectedly regardless of your mechanisms designed to prevent that, because mechanism fail, especially when interactive with other bots.

If it only fires 'safely' with a ball loaded, then that is not good enough, and the robot is considered to be too unsafe for FRC standards, and it probably shouldn't be good enough for your team's standards due to the risk of serious injury.

Make sense?
No, not really. When my shooter dry fires, the lexan arms shatter in an enclosed area at the bottom of the robot. When we break the shooter, it's safer than if it took an actual shot. Standing near an arm smashing itself into the bottom of our robot is way safer than having a 2 lb ball be thrown at you from a foot in front of the robot, and getting the shooter arm to hit you on your head.
Reply With Quote
  #19   Spotlight this post!  
Unread 13-02-2014, 15:36
Jeff Pahl's Avatar
Jeff Pahl Jeff Pahl is offline
likes to look at shiny things...
FRC #5148 (New Berlin Blitz)
Team Role: Engineer
 
Join Date: Oct 2004
Rookie Year: 2004
Location: Waukesha, WI
Posts: 344
Jeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond repute
Re: Al's Annual Inspection Thread

I personally do not trust any sort of "software interlock" to prevent a dry fire of a robot mechanism. We all know that programmers are allowed to tinker with the code after inspection, and there is no sort of control in place to prevent the removal of a software interlock, either intentionally or accidentally.

I realize that the ball being present changes the physics of many shooters. However, it is my opinion that stored energy mechanisms should be designed to withstand the additional stresses of potentially being fired without the ball being present.

These are my opinions. You may not agree with them. However, be aware that I am the individual that presented this section of the rules during LRI training, and these are the opinions regarding this subject that were given during that presentation. There was discussion, but no disagreement on the subject. And I know all the Championship division LRI's are in agreement on the subject.
__________________
Team 5148 - 2014 Wisconsin Regional Rookie All-Stars!!

Mentor: 1379: 2004-2008 / 2530: 2008-2013 / 2861: 2009 / 5148: 2014-??
Lead Robot Inspector: 10,000 Lakes '09 - '11 / Lake Superior '11-'12 / Northern Lights '13, '15 - '16 / Championship '09 - '12, '14 - '15
Attending/Inspecting 2017: TBD, Wisconsin, STL Championship

"Sometimes the questions are complicated and the answers are simple" -Dr. Seuss
Reply With Quote
  #20   Spotlight this post!  
Unread 13-02-2014, 15:42
Andrew Schreiber Andrew Schreiber is offline
Joining the 900 Meme Team
FRC #0079
 
Join Date: Jan 2005
Rookie Year: 2000
Location: Misplaced Michigander
Posts: 4,074
Andrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by geomapguy View Post
If you don't the ability to do stuff manually in your code, then you are setting yourself up for failure. What happens if a sensor goes out during a match....you still want to be able to function without the sensor.

So honestly, just figure it out and stop crying about it...
If a sensor goes out and my default is to not allow firing how is that failure? If we determine that the potential risks of not being in a known good state are not worth the cost of losing a match I would say that is both OUR call to make and the proper call.

This isn't my first rodeo, when designing a system that has potentially dangerous states I prefer to know exactly where things are and be sure that the system protects itself from damage and keeps itself from getting into states that could be dangerous. Dry firing the system is potentially dangerous due to the fact that it bypasses the regular firing procedure meaning any of a handful of other systems could be in the wrong configuration and could be damaged, destroyed, or cause other problems. There is a firing procedure for a reason. If the forks were to hit the intake neither system would likely be destroyed but it would present an unsafe condition for the humans that have to sort that crap out.

Asking for clarification isn't "crying about it" it's making sure we are adequately prepared for any known contingencies. It's something engineers try to do. I will comply with any and all procedures that the LRI's deem necessary to ensure safe operation of robots, I just want to know what they are and what the expectations on my team are.

I would assume you wouldn't talk to one of your mentors as you have just done to me, I will ask you nicely once to change your tone. After that I will be contacting your team leaders to have a discussion about how your team is representing itself online.
__________________




.
Reply With Quote
  #21   Spotlight this post!  
Unread 13-02-2014, 15:44
Jeff Pahl's Avatar
Jeff Pahl Jeff Pahl is offline
likes to look at shiny things...
FRC #5148 (New Berlin Blitz)
Team Role: Engineer
 
Join Date: Oct 2004
Rookie Year: 2004
Location: Waukesha, WI
Posts: 344
Jeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by magnets View Post
No, not really. When my shooter dry fires, the lexan arms shatter in an enclosed area at the bottom of the robot. When we break the shooter, it's safer than if it took an actual shot. Standing near an arm smashing itself into the bottom of our robot is way safer than having a 2 lb ball be thrown at you from a foot in front of the robot, and getting the shooter arm to hit you on your head.
If it is obvious that when your shooter self destructs that all shrapnel will be contained safely inside the robot, then it would not be necessary to dry-fire the mechanism. The safety concern is with a robot where the mechanism is not contained in such a manner and the possibility exists that it could throw parts outside the field border into an area where people are present. Or throw parts into an adjacent pit. I would consider a robot that was designed to contain all parts in the event of a failure to be consistent with the desired intent, and would commend the team on the design.

Unfortunately, however, not all robots fall into that category yet. I eagerly look forward to that day.
__________________
Team 5148 - 2014 Wisconsin Regional Rookie All-Stars!!

Mentor: 1379: 2004-2008 / 2530: 2008-2013 / 2861: 2009 / 5148: 2014-??
Lead Robot Inspector: 10,000 Lakes '09 - '11 / Lake Superior '11-'12 / Northern Lights '13, '15 - '16 / Championship '09 - '12, '14 - '15
Attending/Inspecting 2017: TBD, Wisconsin, STL Championship

"Sometimes the questions are complicated and the answers are simple" -Dr. Seuss
Reply With Quote
  #22   Spotlight this post!  
Unread 13-02-2014, 15:45
jvriezen jvriezen is offline
Registered User
FRC #3184 (Burnsville Blaze)
Team Role: Mentor
 
Join Date: Jan 2010
Rookie Year: 2008
Location: Burnsville, MN
Posts: 643
jvriezen has a reputation beyond reputejvriezen has a reputation beyond reputejvriezen has a reputation beyond reputejvriezen has a reputation beyond reputejvriezen has a reputation beyond reputejvriezen has a reputation beyond reputejvriezen has a reputation beyond reputejvriezen has a reputation beyond reputejvriezen has a reputation beyond reputejvriezen has a reputation beyond reputejvriezen has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by magnets View Post
No, not really. When my shooter dry fires, the lexan arms shatter in an enclosed area at the bottom of the robot. When we break the shooter, it's safer than if it took an actual shot. Standing near an arm smashing itself into the bottom of our robot is way safer than having a 2 lb ball be thrown at you from a foot in front of the robot, and getting the shooter arm to hit you on your head.
Here's my thoughts and response, but I suspect Al will chime in as well...

There are some safety issues that can only be minimized to a point based on the game design requirements. Exposed spinning shooter wheels at output orifice (2012,2013), launched frisbees, etc. This year's game piece is harmful when launched at close range to a person also (though probably likely to cause less injury than from a frisbee.)

So the fact that live firing is unsafe has no bearing on issues associated with the safety of dry firing. The point is to maximize safety to the extent that it can be reasonably maximized. And the threshold FRC has chosen is that dry firing should not result in parts breaking off at high speed. If dry firing is shattering lexan parts, that may not be safe enough, since projectiles and parts flailing at high speed in directions they are not designed to go is the concern here.
__________________
John Vriezen
FRC, Mentor, Inspector #3184 2016- #4859 2015, #2530 2010-2014 FTC Mentor, Inspector #7152 2013-14

Last edited by jvriezen : 13-02-2014 at 15:49. Reason: added a 'not' which makes a big difference
Reply With Quote
  #23   Spotlight this post!  
Unread 13-02-2014, 15:45
Andrew Schreiber Andrew Schreiber is offline
Joining the 900 Meme Team
FRC #0079
 
Join Date: Jan 2005
Rookie Year: 2000
Location: Misplaced Michigander
Posts: 4,074
Andrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond reputeAndrew Schreiber has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by Jeff Pahl View Post
I personally do not trust any sort of "software interlock" to prevent a dry fire of a robot mechanism. We all know that programmers are allowed to tinker with the code after inspection, and there is no sort of control in place to prevent the removal of a software interlock, either intentionally or accidentally.

I realize that the ball being present changes the physics of many shooters. However, it is my opinion that stored energy mechanisms should be designed to withstand the additional stresses of potentially being fired without the ball being present.

These are my opinions. You may not agree with them. However, be aware that I am the individual that presented this section of the rules during LRI training, and these are the opinions regarding this subject that were given during that presentation. There was discussion, but no disagreement on the subject. And I know all the Championship division LRI's are in agreement on the subject.

Thus, can we expect all stored energy launchers will be expected to demonstrate a dry fire as part of the initial inspection and any subsequent re-inspections?
__________________




.
Reply With Quote
  #24   Spotlight this post!  
Unread 13-02-2014, 15:50
magnets's Avatar
magnets magnets is offline
Registered User
no team
 
Join Date: Jun 2013
Rookie Year: 2012
Location: United States
Posts: 748
magnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond reputemagnets has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by Jeff Pahl View Post
If it is obvious that when your shooter self destructs that all shrapnel will be contained safely inside the robot, then it would not be necessary to dry-fire the mechanism. The safety concern is with a robot where the mechanism is not contained in such a manner and the possibility exists that it could throw parts outside the field border into an area where people are present. Or throw parts into an adjacent pit. I would consider a robot that was designed to contain all parts in the event of a failure to be consistent with the desired intent, and would commend the team on the design.

Unfortunately, however, not all robots fall into that category yet. I eagerly look forward to that day.
Thanks for the response. I do understand the point of the rule, as some systems may fail more catastrophically than others.

EDIT: Just to clarify, when we dry fire, the shooter arm goes > 180 degrees into the bottom of the robot where the lexan on the arms shatters. None of the lexan leaves the robot.
Reply With Quote
  #25   Spotlight this post!  
Unread 13-02-2014, 15:57
Jon Stratis's Avatar
Jon Stratis Jon Stratis is offline
Mentor, LRI, MN RPC
FRC #2177 (The Robettes)
Team Role: Mentor
 
Join Date: Feb 2007
Rookie Year: 2006
Location: Minnesota
Posts: 3,827
Jon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by magnets View Post
No, not really. When my shooter dry fires, the lexan arms shatter in an enclosed area at the bottom of the robot. When we break the shooter, it's safer than if it took an actual shot. Standing near an arm smashing itself into the bottom of our robot is way safer than having a 2 lb ball be thrown at you from a foot in front of the robot, and getting the shooter arm to hit you on your head.
And if that's the case, I would fully expect you could explain it to the inspector (and possibly go through a low-energy/slow motion demo to show where the stress will occur without actually breaking your arm) and get agreement that dry firing is safe without requiring full test. I'm not saying we'll require every robot to dry fire... It's a judgement call on safety when a dry fire does happen. If I think the results of a dry fire will be bad (like launching the head of a 30lb sledge hammer into the crowd), then I'm going to arrange for a safe dry fire to see how the system holds up, even if there's a sensor the team swears won't let it dry fire. If a dry fire will result in a situation that's safe for those in the stands and next to the field, then I won't have a need to ask for a dry fire test.
__________________
2007 - Present: Mentor, 2177 The Robettes
LRI: North Star 2012-2016; Lake Superior 2013-2014; MN State Tournament 2013-2014, 2016; Galileo 2016; Iowa 2017
2015: North Star Regional Volunteer of the Year
2016: Lake Superior WFFA
Reply With Quote
  #26   Spotlight this post!  
Unread 13-02-2014, 16:13
kmusa kmusa is offline
Registered User
AKA: Karlis Musa
FRC #0639 (Code Red Robotics)
Team Role: Mentor
 
Join Date: Jan 2009
Rookie Year: 2006
Location: Ithaca, NY
Posts: 117
kmusa is just really nicekmusa is just really nicekmusa is just really nicekmusa is just really nice
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by Jeff Pahl View Post
I personally do not trust any sort of "software interlock" to prevent a dry fire of a robot mechanism. We all know that programmers are allowed to tinker with the code after inspection, and there is no sort of control in place to prevent the removal of a software interlock, either intentionally or accidentally.
I don't believe anyone restricted this to only software interlocks.

For instance, two limit switches in series (which require contact from the ball to close), and connected in series with one of the leads for the solenoid would be robust, and not open to software override.

-Karlis
__________________
"A society without contrasting ideas will never move forward; however those contrasting ideas must be based on fact, must be rational/logical, and must be presented in a respectful manner." -Arthur Dutra IV

"If the district can spend $1.5M on turf, it should be able to fund a FRC team." -Sophie Halter
Reply With Quote
  #27   Spotlight this post!  
Unread 13-02-2014, 16:27
Jon Stratis's Avatar
Jon Stratis Jon Stratis is offline
Mentor, LRI, MN RPC
FRC #2177 (The Robettes)
Team Role: Mentor
 
Join Date: Feb 2007
Rookie Year: 2006
Location: Minnesota
Posts: 3,827
Jon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond reputeJon Stratis has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by kmusa View Post
I don't believe anyone restricted this to only software interlocks.

For instance, two limit switches in series (which require contact from the ball to close), and connected in series with one of the leads for the solenoid would be robust, and not open to software override.

-Karlis
And would be illegal per R53:
Quote:
CUSTOM CIRCUITS shall not directly alter the power pathways between the ROBOT battery, PD Board, motor controllers, relays, motors, or other elements of the ROBOT control system (items explicitly mentioned in R64). Custom high impedance voltage monitoring or low impedance current monitoring circuitry connected to the ROBOT’S electrical system is acceptable, if the effect on the ROBOT outputs is inconsequential.
Note that R64 mentions the solenoid breakout as part of the control system.
__________________
2007 - Present: Mentor, 2177 The Robettes
LRI: North Star 2012-2016; Lake Superior 2013-2014; MN State Tournament 2013-2014, 2016; Galileo 2016; Iowa 2017
2015: North Star Regional Volunteer of the Year
2016: Lake Superior WFFA
Reply With Quote
  #28   Spotlight this post!  
Unread 13-02-2014, 16:33
cgmv123's Avatar
cgmv123 cgmv123 is offline
FRC RI/FLL Field Manager
AKA: Max Vrany
FRC #1306 (BadgerBOTS)
Team Role: College Student
 
Join Date: Jan 2011
Rookie Year: 2011
Location: Madison, WI
Posts: 2,085
cgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond reputecgmv123 has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by kmusa View Post
I don't believe anyone restricted this to only software interlocks.

For instance, two limit switches in series (which require contact from the ball to close), and connected in series with one of the leads for the solenoid would be robust, and not open to software override.

-Karlis
Custom circuits (which your switches are considered) can't alter solenoid pathways, so your system is illegal on non safety grounds.
__________________
BadgerBOTS Robotics|@team1306|Facebook: BadgerBOTS
2016 FIRST Championship Tesla Division | 2016 Wisconsin Regional Engineering Inspiration Award

2015 FIRST Championship Carson Division | 2015 Wisconsin Regional Chairman's Award

2013 FIRST Championship Curie Division | 2013 Wisconsin Regional Chairman's Award

2012 FIRST Championship Archimedes Division | 2012 Wisconsin Regional Engineering Inspiration Award, Woodie Flowers Finalist Award (Lead Mentor Ben Senson)

Reply With Quote
  #29   Spotlight this post!  
Unread 13-02-2014, 16:33
Alan Anderson's Avatar
Alan Anderson Alan Anderson is offline
Software Architect
FRC #0045 (TechnoKats)
Team Role: Mentor
 
Join Date: Feb 2004
Rookie Year: 2004
Location: Kokomo, Indiana
Posts: 9,113
Alan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by kmusa View Post
I don't believe anyone restricted this to only software interlocks.

For instance, two limit switches in series (which require contact from the ball to close), and connected in series with one of the leads for the solenoid would be robust, and not open to software override.

-Karlis
It would probably be an effective system, but it would violate the robot rules. Custom circuits may not affect the power pathways to robot actuators. The only "hardware interlocks" permitted on an FRC robot are limit switches connected to the Jaguar switch inputs.
Reply With Quote
  #30   Spotlight this post!  
Unread 13-02-2014, 16:43
Jeff Pahl's Avatar
Jeff Pahl Jeff Pahl is offline
likes to look at shiny things...
FRC #5148 (New Berlin Blitz)
Team Role: Engineer
 
Join Date: Oct 2004
Rookie Year: 2004
Location: Waukesha, WI
Posts: 344
Jeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond reputeJeff Pahl has a reputation beyond repute
Re: Al's Annual Inspection Thread

Quote:
Originally Posted by Andrew Schreiber View Post
Thus, can we expect all stored energy launchers will be expected to demonstrate a dry fire as part of the initial inspection and any subsequent re-inspections?
No. You can expect any stored energy launcher that, upon review by the LRI, appears to present a risk of catastrophic failure resulting in parts leaving the robot, to probably be dry fired in a safe area. If the robot design is such so that risk does not appear to be present (mechanism is contained, mechanism is significantly robust) then it is reasonable to expect that a dry fire will not be necessary. If a shooter is modified and the modifications appear to possibly affect the structural integrity of the mechanism, then a possible demonstration during a re-inspection is possible. If you worked on some other part of the robot we are not going to re-inspect the shooter each time.

Rule R8 requires that robots not "be unsafe" or "cause an unsafe condition". The burden is on teams to be able to show compliance with the rule. I would welcome teams to provide written analysis that shows that the energy present in the mechanism is not sufficient to cause the materials used to exceed their yield strength, with sufficient margin, in lieu of physical demonstration of the mechanism.

Please keep in mind that if something goes wrong with a robot that we did not verify was safe, and parts go flying into the crowd, that in today's litigious environment, the lawyer's are going to sue everyone they can, including the robot inspectors that said it was safe.

The inspectors are not "out to break your robot". We want everyone to play with a fully functioning robot. But we are also responsible for making sure everyone goes home in the same condition they came in.
__________________
Team 5148 - 2014 Wisconsin Regional Rookie All-Stars!!

Mentor: 1379: 2004-2008 / 2530: 2008-2013 / 2861: 2009 / 5148: 2014-??
Lead Robot Inspector: 10,000 Lakes '09 - '11 / Lake Superior '11-'12 / Northern Lights '13, '15 - '16 / Championship '09 - '12, '14 - '15
Attending/Inspecting 2017: TBD, Wisconsin, STL Championship

"Sometimes the questions are complicated and the answers are simple" -Dr. Seuss
Reply With Quote
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 17:48.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi