Announcement

Collapse
No announcement yet.

Proposal to eliminate part b. of "Latched to the Lander" definition

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Mentor 777
    replied
    Well, it has been about 2 weeks with no official response. Would some of you that are "in the know" please elaborate on the calculation of the 4 inches? What was the intent behind that? I truly believe that the original intent was simply a means to measure the 18 inch cube. It is the only math that makes sense. Therefore, it seems that it should be 3 inches (22 inch stated lander support bracket height minus 1 inch G26 tolerance minus 18 inch maximum robot height = 3 inches minimum clearance). If there was another intent of the design committee, would you please explain that intent?

    Leave a comment:


  • Mentor 777
    replied
    Why is this important to me? The game manuals, combined, are 94 pages long. Rule G26 is an extremely small part of that and probably would not stand out, especially to a rookie team. In fact, it did not stand out to me and my son as we were scouring the game manuals last year looking for a dependable way for precision placement of an arm with a color sensor to determine which jewel to knock off. What stood out to us was Figure F-6 of Game Manual Part B, which mentioned both in the description and the picture that the pictograph is to be placed 3 inches offset to the left of the center of the balancing board, which also happened to be the center of the rack that was holding the jewels. Also, Step 8-3 of the Field Setup Guide states

    Basically, we developed a program based on a relationship given in the game manual and the field setup guide. It was brought to moot since a general area was used instead of the 3 inch measurement that was called for. Rule G26 was the excuse.


    When the improper placement was pointed out, the officiating person was not aware of 3 inches being mentioned. He asked where it was in the game manual. It was in 3 places, actually - the game manual, the field setup guide, and the answered questions (clarified that the 3 inches was to the edge of the paper). If the official in charge of the competitions did not know a measurement mentioned in 3 official spots, how much more easily can a new team miss that little G26 in the middle of 94 pages of paper?

    With outreach being encouraged in FIRST, new teams theoretically are added each season. Spending hours planning something based on the stated rules only to have the field an approximate representation of the game manual is extremely discouraging. We were not going to participate again. However, the design and build stage is very enjoyable. It provides a lot of awesome quality time with my son. The challenge of the game design is well thought out and provides several unique challenges. We had probably over a dozen fist bumps on the drive home just last night after we mounted the lift mechanism we have been discussing and planning since the kick-off. It worked amazingly well and was very exciting.

    With a few simple changes, the competitions could be equally fulfilling. We have a fix for our robot, but many teams will be planning their robot based on the stated guidelines. Those teams will be very disappointed when they discover the extra challenge of the 1 inch part not being included in the math of the 4 inch rule. If I could somehow convince the design committee to re-consider that rule and alleviate the frustration we experienced for just one team, my time posting on this issue will have been well spent.

    Will someone from the design committee please answer two question? Was the fact that an 18 inch tall robot must have an attachment point at least 1 inch below the top of their robot in order to fulfill the obligation of the 4 inch minimum clearance once G26 is considered ever discussed? In coming up with part b of "Latched to the Lander", was rule G26 taken into consideration at all?
    Last edited by Mentor 777; 11-14-2018, 10:37 AM. Reason: Much of the original post was somehow deleted. I haven't figured out what the board doesn't like yet. Something to do with quotation marks? I now have some time to elaborate.

    Leave a comment:


  • Mentor 777
    replied
    Originally posted by 3805Mentor View Post
    ​ I tried to post a link to our team's robot that shows it is 18" tall, 5" off the mat, with a hook not at the top of the robot. It scores deployment.
    The link was mangled and now I can't leave the editor without a valid URL, and I can't figure out how to turn off the add link, so here's FIRST's link
    Again enjoying dealing with this forum.
    Thanks! Yes, a hook that is not at the top is the only option to ensure compliance with the 4 inch rule with an 18 inch cube robot, factoring in rule G26. It's been a few decades since my civil engineering classes, but it seems like that adds some to the rotational force.

    Our original design had the hook at the top, in the middle of the robot. A portion hung underneath the lander, creating a good balance with the only contact with the lander being the hook. That seems to me to be the optimal setup since it eliminates rotational force on the lift mechanism. However, the dividing line between the alliances only gives a very small amount of room that a robot can hang underneath, especially on the corners next to the line.

    So, the only way to attach produces rotational forces that add complexity to the issue. The attachment point has to be at the edge of the robot. Our current design has the hook at the top on the back of the robot. The height of the hook is 17.5 inches, leaving a half inch wiggle room. With a proper field setup (according to the game manual), this works well. However, throwing in rule G26 and the 4 inch rule, we have two options. Lower the robot another half inch or place the hook lower. We have a fix in mind that lowers the hook an inch, but it will take a bit of re-configuring.

    Perhaps that was the intent of the game design committee. Engineer the rules so that teams are forced to either go with a 17 inch tall robot or place a hook an inch lower than the high point of the robot. Perhaps someone from the game design committee could comment here to let us know the intent of the 4 inch rule. Was an attachment point lower than the top of the robot a discussion topic? Or is my theory correct that the 4 inches is simply a way to measure rule c easily and Rule G26 was not factored into the equation?

    My team will be good. 3805Mentor's team is good. Teams that actually read the forum will see this thread and adjust their robot to either be 17 inches tall or have an attachment point at least an inch below the top of the robot. However, what percentage of overall FTC teams even read the forum? I'm guessing the percentage is below 50. That would leave a lot of teams that are designing their robots expecting a 22 inch measurement from the top of the tile to the bottom of the lander support bracket. As the two teams that have posted their experience, they will learn the hard way that all of their hard work in designing their robot is brought to naught because the small feet of the lander sunk into the soft foam of the playing field causing the bottom of their robot to be less than 4 inches from the top of the playing field. 80 points that they worked hard for are gone in a flash.

    I do not believe that is the intent of the game design committee. Some of the design folks will see this post. It is still early in the season. If my theory is correct and part b was conceived simply as an easy means to enforce part c, then rule G26 needs to be factored in and the limit changed to 3 inches.

    Leave a comment:


  • 3805Mentor
    replied
    ​ I tried to post a link to our team's robot that shows it is 18" tall, 5" off the mat, with a hook not at the top of the robot. It scores deployment.
    The link was mangled and now I can't leave the editor without a valid URL, and I can't figure out how to turn off the add link, so here's FIRST's link
    Again enjoying dealing with this forum.
    FIRST designs accessible, innovative programs that build not only science and technology skills and interests, but also self-confidence, leadership, and life skills.
    Last edited by 3805Mentor; 11-12-2018, 09:00 PM.

    Leave a comment:


  • Mentor 777
    replied
    Actually, this rule seems to be in direct conflict with long standing game rules. The robot has long been allowed to be 18 inches tall. The rule G26 has long given a 1 inch allowance. The height of the lander support bracket is stated to be 22 inches.

    Therefore, the only way a hanging robot can meet the 4 inch rule is to be 17 inches (22 inches stated height minus 1 inch G26 tolerance minus 4 inch minimum clearance). This is in direct conflict with the long-standing stated maximum robot height of 18 inches.

    Instead of eliminating part b, it should be changed to 3 inches to be congruent with the other game rules (22 inches stated latch height minus 1 inch G26 tolerance minus 18 inch robot maximum height).

    Leave a comment:


  • Proposal to eliminate part b. of "Latched to the Lander" definition

    The game manual states that the height of the lander support bracket is to be 22 inches. The game manual also states that the maximum size of a robot is an 18 inch cube. 22 inches minus 18 inches equals 4 inches. Part c of the definition of "Latched to the Lander" states that the robot is to be within the 18 inch cube when completely supported by the lander.

    With all of these factors, part b is redundant when the field is setup as expected. The game was apparently designed with these measurements in mind. My guess is that part b was added as a way to easily measure part c. It would be impossible to put an 18 inch cube box over a hanging robot to make sure it fits within the appropriate starting requirement. Since 22 inches minus 18 inches equals 4 inches and a 4 inch clearance is easily measured, hence came part b.

    If my theory is correct, the only reason for part b is to easily measure part c. Therefore, the intent of part b is simply to ensure that the bottom of the robot is no more than 18 inches from the lander support bracket. There are 2 stated examples on the forum already of the lander support bracket being 21.5 inches instead of the stated 22 inches at competitions. It appears that somehow in the design phase, the soft foam of the mat was not taken into account. The math works fine on the setup. However, the feet of the lander are relatively small and the foam is soft. Tightening a nut too much can easily cause the feet to sink into the mat, reducing the height of the lander support bracket. The weight and shakiness of up to 4 robots pushing, moving, and hanging from the lander throughout the course of the day in a competition are even more likely to cause the feet to sink into the foam.

    Since the original intent seems to be simply a means to measure part c and the feet sinking into the soft foam does not seem to be a factor that was considered in the design stage, the fair and professional action seems to be to eliminate part b of the definition. Teams that have worked hard on their autonomous programs should not be penalized for the failure of the system design.
Working...
X