I am wondering what other people are thinking about for designs for toss up? I personally think that speed and mobility will be large factors this year what do you guys think?
Side rollers from gateway
Nz Design from Gateway.
I think the Q&A questions I have going indicate what some people on our team want to build…
Additionally, I think we’ll actually be building an offensive robot for the first time in a year. Plus the first thing. And another side project. We have no ideas set in stone yet. After doing 5-7 hour meeting for a straight month to be ready for Worlds, it’s time for a short break. Just some drawing, strategizing and CADing.
Sack Attack finished less than 20 hours ago. Sure, we’re thinking, but I don’t expect to see any building done for at least a week or two, and even that will be limited to maybe a couple hours a week. We need to order a full field, get the sensors and metal we want, plus more Pneumatic cylinders, pistons and tubing, AND recruit more people for the team.
VEX doesn’t really have an off-season, but you don’t need to run the entire year like FRC. Take a few days off.
type 1: efficiency
-NZ type gateway robot WITH additional “catapult” addon
-hanging winch because its easy and uses a motor
type 2: defence
-wallbot, goal capper, etc
-hang as well cause its easy
type 3: game breaking designs
-goal descorer + hang with large ball
not sure if “large ball on the goal” will be a goal many robots will aim for because
a) it is difficult
b) the points incentive isnt that much
c) it is VERY easy for others to knock down
just my first thoughts on the new game
mec drive, scissor lift, 2 different intakes …
all aluminium with hook on scissor lift …
elecky on intake … base = light
ta dah !
I’m “Tossing up” a few designs. Think the “gateway” to the best robot needs to be “rounded up” so that way we can “clean sweep” the competition. However we may want to put things into “overdrive” in mid season so we aren’t just “hanging around” and get “bowled over” by other teams.
I got so excited and thought I was the only one who had the NZ Gateway design in mind… then I came here and saw other’s were thinking about it too…
I don’t know what it is about gateway, and the “NZ Design” that it spawned, that seems to have stuck with the VRC community like glue. It was undeniably a great design for Gateway, winning dozens of regional events and performing very well at the world level, to the point that many of the top Gateway robots in the world almost blurred together. And looking to the past, and designs that worked then, is definitely a great way to learn, and step up performance in the competition. But blindly following the designs of the past because they were good then is only going to cost you. To truly perform, and lead the pack in VRC, you have to understand why the NZ design performed as it did, in Gateway, and the numerous differences between Gateway and Toss Up that may make it not perform as well. The NZ design is not a one-size-fits-all “efficiency” design, suitable with a few minor tweaks, for any VEX challenge. Understanding these differences will also help you generate ideas as to what might be the next “NZ Design” of VRC for the 2013-2014 season.
Several things that you should be considering:
-In Gateway, it was quite common that you would want to score one object while holding several, or pick a doubler barrel off the top of a loaded goal, both making a scoring device that fed out the intake efficient and advantageous. Neither of these conditions are present in Toss Up.
-In Gateway, you had two gamepieces, one of which rolled nicely, and one of which did not. This made side rollers advantageous, as they are suited to handling objects that do not roll nicely, as with the tank tread flaps, which are suited to providing predictable compression on objects of unpredictable orientation. In Toss Up, the gamepieces are relatively symmetric, and may to your surprise roll quite well when under the influence of a top roller, or something else.
-In Gateway, the gamepieces were roughly the same size, and worth the same amount of points. In Toss Up, they are not. Furthermore, the gamepiece better suited for the “NZ Design” is worth less, signifigantly so in the far scoring zone.
-Gateway’s 30" tall goals demanded the extra reach of a six bar linkage, and the poor (in comparison to some other systems) mechanical performance that comes with it. Does Toss Up?
-If you plan to score in the goals from the goal zone, the height differential from max height imposed by the barrier to goal height is greater than gateway’s differential from starting height to 30" goal height. Is the design methodology of “However many Watts Parallelogram 6 bar linkages stacked upon one another it takes” the best, with that kind of height difference?
-The NZ design’s ability to score out the same end the gamepieces enter demanded that the intake remain parallel to the ground. Sack attack descoring machines had the same requirement. Is this requirement present in Toss Up?
-In the early weeks and months of Gateway, many designs came out that were much better with the balls than the barrels, or vice versa. This one, on the other hand, might just be a similarity worth paying attention to…
-In Gateway, there was no terrain, or reason to be low to the ground. In Toss Up, there is.
-Gateway’s “high reach” challenge, the 30" goal, demanded an active device up that high to make use of it, as well as the ability to carry game pieces, necessitating a rigid system to reach that tall. Does Toss Up’s “High reach” challenge, the hang, have the same requirement?
-In Gateway, there was no possession limit, and objects littered the field to a degree that made distance from pickup to scoring often trivial. In Toss Up, it is to your advantage to get objects from one end of the field to the other as fast as possible, whether you’re scoring or descoring. Is a drivetrain the fastest way to convey gamepieces, as it was in Gateway, or is it something else?
-If recent games are anything to go by, teams should have no problems maxing out the “Gateway-like” goals well within the time limit of a match. In fact I wouldn’t be suprised to see them half full by the end of autonomous in many matches. If that can be assumed to be the case, consider whether or not these “Gateway-like” goals are truly the part of the field on which the game will be won and lost.
-In Gateway, there were enough gamepieces to max out the goal capacity. In Toss Up, by comparison, gamepieces are in relatively short supply, and maximizing their scoring potential is more important than scoring speed and volume.
-Gateway was a game of precision, with all scoring done in small goals that demanded it. In Toss Up, 2/3rds of the field is a scoring zone, allowing designs that prioritize speed and volume to precision. The “NZ Design” was undeniably very fast, for Gateway. But when some of the unique challenges and restrictions Gateway placed on you are lifted, you may be able to go faster.
-In Gateway, there was plenty of video footage of “NZ Designs” intaking efficiently, that left little doubt as to the effectiveness of the intake style. No such footage of any intake exists with the gamepieces as of now, and the smart thing to be doing is experimenting, not speculating.
-It is certainty possible to adapt the NZ design to these challenges, as was done quite often in Sack Attack. But what will seperate the best from the good, are the teams that think “but could we do it another way?”
A thorough analysis reveals that Toss Up appears to have followed a dramatically different design philosophy than some recent VRC games. Gateway, Sack Attack, Clean Sweep, Elevation, Bridge Battle, and to a lesser extent, Round Up, all had one central, repeatable task that absolutely dominated match play, and was eclipsed only in some cases by a side-task (gateway wall bot, clean sweep locked-up balls), and in others, not at all. Toss Up does not appear to be this way. It appears to have taken some of it’s design cues from older FRC games, which offered a number of tasks, all with value but none with the potential to win singlehandedly, along with some brutal sizing tradeoffs, forcing specialization. This means it takes more analysis to play effectively, since the basic design criteria of a winning robot is not immediately clear.
I’ll leave you all with this, a robot and game that is quite worth your time to look at
Please explain how a 6-bar is mechanically disadvantageous to other systems (such as)? A 6-bar is equivalent to a 4-bar in almost every way (torque/power/speed) wise, with the added advantage of a greater range of motion, meaning greater possible height. Friction is negligible (while not even being necessarily bad for a lift).
They are ever so slightly heavier, and are more difficult to explain to inductees. The four bar is the simplest and that is what makes it useful.
It’s 5 points a pop for scoring in the hexagonal goals vs. 1 point in the middle zone and 2 points in the goal zone. . The bucky balls would also remain scored unless the opposing robot is capable of reaching into the goal. Personally, I’d go for the two hexagonal goals at the start of the match and cap those first. And side rollers would not be a bad place to start as a first prototype.
Could someone possibly explain what this “NZ Design” is?
The single jointed pivoting arms, and the elevators would like to have a word with you
Neither weight nor friction, nor lack of mechanical play nor simplicity/reliability are trivial on a robot designed for speed. I have seen plenty of six bar designs (and other VEX linkages) that minimize these factors, but plenty of others that do not. Some times, this is due to bad design, but sometimes, this is forced as part of trade-offs.
Additionally, a “Maxed out” 6 bar (one designed to the maximum size the VRC starting box allows) will have a longer lever arm, and require more torque to lift, than a “Maxed out” 4 bar (you can’t get your extra height for free). A frictionless, massless 4 bar and 6 bar with the same lever arm would have the same theoretical torque requirement, but this comparison is invalid, since that larger 4 bar is not VRC-legal without some extra skullduggery. Yes, the shorter 4 bar has less total reach, while being quicker. Again, this was all small potatoes compared to their advantages in Gateway, and they were justified. My question is, do you need that now? The answer may well be yes, but it’s a question you should ask each and every time you pull out the drawing board.
Finally, both linkages suffer from the issue of transmission angle, the variable angle through which the coupler (on a 4 bar, the link that carries the manipulator) transmits force to the rocker (the long link that is not powered.) If this transmission angle is very low, which it is at the extremes of the linkage’s motion, especially if the total angular motion of the linkage is very large, approaching 180 degrees, the system will take more force to get moving. This is because the force vector applied by the coupler link, along the axis formed by it’s two pins, is applied at a poor angle to apply a moment to the rocker. Instead, large percentages of this force are applied axially along the rocker link, doing nothing but trying futily to compress or stretch the rocker, while a relatively small percentage of the motor’s torque actually goes towards accelerating the linkage to normal speed.
Now, both types of linkages have this problem. But it’s more pronounced on the six bar, because it effectively has two couplers (the mid-linkage ternary link and the manipulator), and two rockers (the non-powered grounded link, and the upper long link of the “manipulator side” of the linkage.) This doubles the effect. So, once a 4 bar and a 6 bar are in motion, they are equivalent. But to get them into motion, this bit of dynamics makes the 6 bar less efficient. For a more dramatic example of this effect, build an 8 bar, 10 bar, etc, or a scissor lift. You can really feel how much this effects the starting torque.
And again, consider whether or not you need to maintain parallel motion with the ground. It’s been a good idea the past 3 years for various, and different, reasons each time. Is it still? Do the advantages justify it, over the complexity and weight that comes with a linkage system? Are there cool things that you could do with a linkage mechanism other than parallel motion that may provide an advantage? These are the kinds of questions you need to be asking.
Unfortunately, this is a moot point; basically what it is saying is that the longest 6-bar you can fit in 18x18 requires greater torque than the longest 4-bar you can fit in 18x18. But this is trivially true because the 6-bar is longer, and also largely irrelevant because (1) you can shorten the 6-bar to match the 4-bar, and (2) there is rarely a need for a “maxed out” 6-bar.
Rarely is there a need for a 18sqrt(2) length “maxed out” lever bar on either a 6-bar or 4-bar. However, with the same length lever arm on a 4-bar or a 6-bar, the 6-bar can reach a greater height than the 4-bar. This is because the 6-bar has a greater range of motion than the 4-bar, because the lever arm can be mounted higher on the arm tower, and so the end of the lever arm can start more angled downwards.
Taking this a step further, say you have an 15" 4-bar that reaches a height of 25", and a 15" 6-bar that reaches 28". You can then shorten the 6-bar to (say) 14", and still have it reach 25" (the same as the 4-bar). The shorter 6-bar requires less torque. Thus, with the same amount of motors on the arm, you can lift more game objects than if you had a 4-bar.
Of course, you can’t get anything “for free”…
The tradeoff for being able to lift more game objects is that the 6-bar would require more time to lift. 1492X this year had a 17.5" arm, while 1492A had a 12.5" arm. The 12.5" arm lifted around 50% more sacks, while taking 30% more time to lift. There is a tradeoff for everything, and in this case, it was the amount of sacks you could lift versus how fast you wanted to lift it. This does not make a 6-bar mechanically disadvantageous, though. You do have to ask yourself what want most in your arm.
While this is correct, it is also true that at the extremes of the linkage’s motion, the arm requires less torque to lift, because gravity applies force to the load at an angle to the lever arm. The load is hardest to lift when the arm is fully extended; however, in this case, the transmission angle is 90 degrees, in which a 6-bar and 4-bar are equivalent.
In the end, the point JoeG is are getting at is to not copy blindly. Rather, consider the tradeoffs of each system you are trying to use. A 6-bar can give you greater height, or let you lift more, but a 4-bar could be simpler to build, and overall more efficient, especially if you do not need the extra height.
This is a very insightful statement that I think will make designs very interesting this year.
do you get more points for hanging with more than one ball or is it the same as just one?
It is stated in the rules you will only get the 10 additional points for the first ball. I spent drive back to Las Vegas going through the whole manual.
One thing I saw that seems slightly confusing is the note within the definition of hanging with a ball. It says “A Robot will never be considered Hanging With A Ball with more than one Large Ball. A Large Ball can only be counted towards a single robot Hanging With A Ball.” Does that mean that if you are hanging with more than one large ball, you don’t get any bonus points, or does it just mean that you only get the points for only one large ball?