General Robot Rules - Answers

[JoAnn]

Answers to questions about General Robot Rules can be found in this section.

[Buzz]

Question 1: May we use a vacuum/suction cup mechanism for grabbing glyphs and relics?

Question 2: Can we use a pre-made one if it comes with a robotics kit?

Answer 1: Yes, provided that the vacuum/suction cup does not damage the Scoring Elements.

Answer 2: Yes, it is legal to remove a single degree of freedom part from a commercial off the shelf mechanism and use it on a Robot.

Caution: This post does not address the legality of using a vacuum pump mechanism. A commercial off the shelf vacuum pump is not legal if any of the following apply:
a) If it compresses air in any form it is illegal per rule <RG01>j.
b) If there is more than one degree of freedom (i.e., pistons, valves, etc.) then it is illegal per rule <RM02>.
c) It is not legal if the vacuum pump motor is not listed in rule <RE09>.

[Buzz]

Question 1: Our team has been wondering about the sizing of the robot. We have a plan whereby our robot fits in the sizing cube when inspected, but extends outside the 18 inches when holding a glyph at the start on the balancing platform. Is this allowed?

Question 2: If it's not allowed, does the robot have to hold a glyph to start?

Thank you,
FTC Team 12952

Answer 1: No. The Robot is required to be no larger than an 18-inch cube when it is waiting for the Autonomous Period to start. The pre-loaded Glyph may extend outside the 18-inch volume constraint; however, Robot parts may not extend outside the 18-inch starting volume constraint. See rule <RG02> in the Game Manual Part 1 and rule <G3> in the Game Manual Part 2 for the complete details.

Answer 2: The Robot is not required to "hold" the pre-loaded Glyph; contact with the Robot is acceptable. The pre-Match setup requirements described in the Game Manual Part 2, section 1.5.1 requires the pre-loaded Glyph to be in contact with the Robot.

[Ming the Merciless]

Subject: Extendable Arm

Q: Our robot uses a rigidly attached extendable arm for intake, driven by two mecanum wheels on the field while the robot is stationary instead of being driven from the robot. This is intended simply to allow the arm to be lighter because it doesn't need to bear as much weight. It is not a "tether" as detailed in <G14> because it is attached by a scissor lift which can only pivot in one axis and is dependent upon being rigidly attached to the robot in order to work and move (i.e arm portion has a very important mechanical function and is not simply for delivering power to the robot: it constrains the mecanum system to the robot so that it has few enough degrees of freedom to be controllable, holds the end of the arm up so it doesn't fall over, and also allows the arm to retract back into the robot effectively) but we still would like to check to make sure.

A: An arm made from rigid elements that are linked together by pivots or sliders is not considered a Tether and is a legal mechanism. The arm as you have described seems to fit this description and therefore is legal.

[Ming the Merciless]

Subject: Team Number Placement

Q: Traditional FIRST Tech Challenge configurations for robots have team numbers placed on the side of the robot. Due to some design choices made this year for our team, we would like to have our team number mounted on the top of the chassis of the robot. We believe this option meets the intent of <RG05> and seek confirmation as we believe there is some room for interpretation within <RG05b>. Some believe the 180 degree requirement to be specific to the numbers themselves (hence the placement of numbers on the side of the robot 180 degrees apart) but we believe as written it applies only to the numbers being visible from 180 degrees around the robot.

A: No, numbers on top of the robot do not meet the requirements of Rule <RG05>.

[Ming the Merciless]

Subject: Vacuum Pump

Q: According to post: https://ftcforum.usfirst.org/forum/i...1809#post51809 Vacuum/Suction Cups are legal and according to RG01, you cannot compress air. Is creating a small vacuum to remove air from the vacuum cup considered compressed air? We have a syringe and we hooked up the plunger to a linear actuator with a standard motor that pulls the plunger to create the vacuum. Then reversing the motor releases the vacuum to drop the block. There is a simple hose that connects the syringe to the vacuum cup. During this part of the operation, the hose is open to the air and zero pressure or vacuum is stored. When the vacuum cup connects with a block, the driver powers the plunger to create the small vacuum. This is enough to pick it up and place in the cryptobox. Also, the small amount of vacuum created does not damage the blocks. The small vacuum does not damage the field elements and the system is not a closed air system.

A: Pulling a vacuum using a syringe is legal however reversing the direction of the syringe and forcing air out through tubing and the suction cup can create a positive pressure and is illegal. This is especially true in circumstances where the Glyph may be squeezed between the Cryptobox and the suction cup which would result in higher than atmospheric pressure in the syringe before the cup releases it's grip on the Glyph.

[Ming the Merciless]

Subject: Vacuum Pump

Q: This is more of a clarification for our team. We could not find a vacuum pump that had only one degree of freedom. If we design and build our own vacuum pump with more than one degree of freedom, including the valves and construct our own diaphragm, would it be a legal part? Thanks.

A: Teams may build their own vacuum pump but they must be designed in such a way that there is absolutely no possibility of positive pressure building up in the system. This is especially important in situations where the Glyph or parts of the vacuum system may get jammed. If a jam occurs and the system can possibly create a positive pressure, then the device is illegal.

[Ming the Merciless]

Subject: Rigid Cone

Q: We are seeking clarification of FTC 7048's post on 11-14. We would like to know, if we used a syringe with a sturdy cone instead of a suction cup, if that would be legal. We have tested the system and we can not get pressure to build up more than the original atmospheric pressure we started with.
.

A: The concern we have is that if the cone is placed hard against the glyph (essentially sealing the cone) and the glyph is pinned against the wall,(or Cryptobox, robot, etc.) and the syringe is activated will pressure build up in the components of the system (tubing, cone, etc.). Since there is no place for the air to go the pressure will have to increase and this is illegal.

[Ming the Merciless]

Subject: Spring Powered Linear Slide

Q: Is it legal for this year's game to build a multi-stage linear slide with the rubber bands or surgical tubing as the force to shoot out the extrusions? The slide can reach up to 50" long and the shootout takes less than a second. Definitely, this will be done within the field perimeter walls before or during the end game. .

A: Spring loaded linear slides are legal however they must be used in such a way that they are safe to the team, field personnel, and other robots. Because of the unusual hazard potential there must be warning labels so that FTAs, referees, etc. are aware of the issue when working around your robot. Also, if the device should illegally extend over any perimeter wall or contact a robot or person with force, your team will be subject to the penalties outlined in Rule <S1> and <S2>. Please note that if the mechanism should fail and the extrusion become detached and shot outside the field you will be asked to remove the mechanism until such time as it can be shown to be safe.

[Ming the Merciless]

Subject: Number Spacing

Q: Our team numbers are going to be spray painted (with a stencil) on the side-plate of our drivetrain. Due to holes in the center of the plate used for motor mounting, the first two and last two numbers are separated by about 6 inches horizontally. Is this legal?

A: Yes, as long as the field personnel can easily determine the team number a small gap between the digits is acceptable.

[Ming the Merciless]

Subject: Vacuum Generators

Q: From previous posts, the Game Design Committee is not concerned with mechanisms that create a small vacuum. But those mechanisms, try to return the negative pressure to zero may have a mode that can cause pressure build up. If the system has a proven way (can be demonstrated during robot inspection) that pressure cannot build up, is that legal? There are multiple solutions to preventing pressure to build such as a one-way valve. Our demonstration can show that blocking the vacuum cups will never allow pressure to build up.

A: You are correct, vacuum generators are legal, it the mechanism that returns the system to atmospheric pressure where the safety concern resides. Teams that are using vacuum must be able to demonstrate at Inspection that the system for bleeding the vacuum cannot build up pressure above atmospheric under any circumstances.

[Ming the Merciless]

Subject: Bill Of Materials

Q: Is a bill of materials required this year? We have not seen anything in this year's game rules about it. We also don't see the bill of materials format on the FIRST website. Thank You.

A: No, a Bill of Materials is not required.

[Ming the Merciless]

Subject: Sizing Box

Q: We have seen at tournaments where during hardware inspections they are putting the robot inside of the sizing box and then trying to slide a piece of paper between the box and robot. If the paper doesn't fit they aren't passing you. Is this a valid method to verify 18" sizing? We thought as long as the robot wasn't exerting pressure on the box that it could be exactly 18". Not 18" minus the width of a sheet of paper. Thanks!

A: A Robot is allowed to touch/rub against the inside of the sizing box providing the interior surface of the box is not constraining the bot. For instance, if a Robot were a perfect cube measuring 18 x 18 x 18 it would touch all sides but still be legal. However, if a part of the robot sticks out, say a zip tie, but when the Robot is placed inside the box the zip tie is deflected to fit inside the 18 x 18 x 18 size then this is not legal since the box itself is constraining the Robot. While sliding a piece of paper is a convenient way to determine if a robot is touching the side of the Sizing Box, the fact that a piece of paper cannot fit between the bot and the Sizing box is not a correct method for determining if a Robot is legal.

[Ming the Merciless]

Subject: Phone Cover

Q: To access our phone (which looks to the side of the robot), there is a clear plastic cover that is hinged at the top. If/when we needed to access that phone, we swing the cover out and up. There is a magnetic latch at the bottom of the cover to keep it secured during the matches. With the cover closed, our robot fit the 18 inch limiting dimension for robots.
There is a concern that when opening the cover to access the phone the cover exceeds the 18 inch limiting dimension for robots and it might be considered illegal. Of course, the cover was only open during setup (and then, only if there was an initialization problem).

Is such a hinged cover for the robot controller phone legal?

A: A hinged cover as described is legal. It does not have to stay within the 18" cube when opened providing the cover is closed at the start of the Match.