Robot Inspection - Answers

[Administrator]

Answers to questions about Robot Inspections are found here.

[Raj]

Rule SG-15 says that the ball-holding capacity of a robot cannot exceed 15 balls, but two things aren't clear to me.

First, the rule suggests that the robot isn't inspected for ball holding capacity unless and until it has committed an offense of holding more than 15 balls. In other words, a robot that is theoretically capable of holding more than 15 balls is "okay" as long as it follows the rules and doesn't in fact control too many. Only after a penalty for having too many balls would the robot be required to make a modification to eliminate the possibility of future offenses. Is that the intent? Or will robots be inspected for ball holding capacity at the outset of the competition?

Second, in deciding whether the 15 ball capacity limit is met, do we count just the ball storage mechanism or must we also account for the fact that a ball pick-up mechanism, in a sense, also carries/controls balls at least in a transitory manner. Many robots will have both a ball-holding mechanism (e.g., a storage bin of some kind) and a ball pick-up mechanism of some kind. The purpose of the pick-up mechanism isn't to hold balls, but in at least some designs the pick-up mechanism may have several balls in it at a time as the balls are being lifted. Must that capacity also be considered, or just the capacity of the ball storage mechanism itself?

First - Not true. Robots WILL be inspected for ball holding capacity during inspection. Please refer to Rule <I2>
Second - the entire robot is considered when testing the 15 ball capacity limit. This includes pick-up mechanisms, arms, hoppers, and more.

[Raj]

<Question regarding racquetball capacity that included robot design that we will not comment on>

From the GDC: There have been many questions about the 15 Ball limit including asking if a certain design is legal or not, so let's try to put it simply. Robots that have the ability to hold more than 15 racquetballs in their Ball travel paths and storage areas will NOT pass inspection. Balls stored in Ball Crates and Balls that are NOT "held captive" with the robot powered off will NOT count towards the 15 ball limit.

Robot inspectors will observe while teams fill all of the Ball travel paths (intake, conveyor systems, etc.) and storage areas to their maximum capacity with the robot powered off. The robot can be powered on if needed to fill a conveyor system and then powered off while determining the ball capacity. Ball Crates will not be present during this test. Areas that hold Balls "captive" in a travel path or storage area will be counted towards the 15 Ball limit. Areas that always "shed" Balls due to gravity when the robot is in a powered off state will NOT count towards the 15 Ball limit. Examples of areas that shed balls are sloped PVC pipe, ramps, etc. that do not have a mechanism to block ball travel. If a robot has a mechanism for blocking ball travel, the robot will be tested with the mechanism in both the open and closed position. The state (opened or closed) that enables the robot to hold the most balls will be used to determine the ball holding capacity.

Tip from the Game Design Committee: This rule is in to disallow teams from hoarding balls. Rule violations that will disallow a robot to pass inspection is a very good indication that the GDC doesn't want teams to do this.

[Professor Proton]

Can the ball holding capacity of <SG15> be limited by software or physical interlocks, or is static capacity the only acceptable criteria?

To help illustrate the question, this is a specific example: "If a ball holding mechanism has sufficient space to hold 20 balls, but the robot counts the number of balls in the mechanism and prevents more than 15 from entering, does that satisfy the ball holding capacity limit of SG15?"

I encourage the answer to be "yes". It would be OK with me to say that if interlocks are used to limit the ball holding capacity and if it is not obvious during game play that these interlocks are effective, the referee or inspector can request that the interlocks be changed to reduce the number of contained balls such that it is clearly below 15.

The robot described in this post would not pass inspection because it has the capacity to store more than 15-balls. The robot inspection procedure is described in post #3 of the robot inspection thread.

[Professor Proton]

Last year, teams were required to provide a "cut sheet" as part of the bill of materials showing the amount of sheet aluminum and sheet plastic used on the robot. This year, a cut sheet is not mentioned in the game manual, and the bill of materials only seems to require some basic dimensions for the sheet types used (thickness, maximum side length, and area for aluminum only).
Q1: During this year's inspection process, are teams required to present a cut sheet or individual part drawings for custom sheet parts (polycarbonate, aluminum, etc)?
Q2: Apart from listing the total area of sheet aluminum used on the BOM, are the bill of materials requirements different for aluminum than they are for the other sheet materials? Thanks.

A1: Cut sheets are not required for the Bowled Over! season. The engineering notebook should contain dimensioned sketches/drawings and calculations for all materials with total area or length constraints to verify that they comply with rule <R5>c. Teams should bring copies of these engineering notebook entries to hardware inspection.
A2: No.

[Raj]

In the sample posted it seems to indicate the BOM needs to only include non-Tetrix/Lego parts, is that correct is do we need to include a comprehensive list including every single piece?

A: Rule <R6> states: All parts listed in <R5>c that have a maximum constraint and that are used on the robot must be tracked through a Bill of Materials (BOM). The parts in <R5>c are non-TETRIX/non-LEGO parts. So you don't have to track all of the TETRIX parts. Nor do you have to track every compatible screw, nut, washer, etc. Only the parts that have a size constraint (e.g. plastic, aluminum sheet, etc.).

[Professor Proton]

We have a robot that has a harvester on the back of it. We have zip ties attached to the harvester to help pull the balls into it. Our robot it just under 18" long without the zip ties hanging off the back. However, if you put an 18" x 18" x 18" box over the robot the zip ties are pressed between the robot and the box so it fits. Our question is if this is acceptable since it still fits inside the box?

The sizing box is a tool used by robot inspectors to verify that a robot, while in its starting configuration, doesn't exceed the 18" x 18" x 18" size constraint. If the robot exerts force on the sides or top of the box, the box is helping the robot to stay within the size constraint and the robot therefore violates rule <R4> and it will not pass inspection. The robot described in this question violates rule <R4> and would not pass inspection.

[Wil Wheaton]

I have a question about the following clarifications. The first post would state that any place that balls are not "held captive" by the robot (pvc pipes/ channels with stopping device) and naturally shed the racquetballs would not count toward the 15 ball limit. The second post one the other hand seems to say the opposite, that those ramps would count toward the 15 ball limit. Which of these interpretations should the teams plan on?

GDC Twinkletoes

Question about <SG15> during inspection.

Originally Posted by 2010FTC3848
If our robot is dropping balls into a crate located on a flat surface on the back of the robot, during inspection would this flat area be counted in determining whether or not the robot violates the 15 ball limit of <SG15>?

A: There have been many questions about the 15 Ball limit, so let's try to put it simply. Robots that have the ability to hold more than 15 racquetballs in their Ball travel paths and storage areas will NOT pass inspection. Balls stored in Ball Crates and Balls that are NOT "held captive" with the robot powered off will NOT count towards the 15 ball limit.


GDC Medic

Originally Posted by FTC2891
If there’s a ramp/tube on a robot that racquet balls go through but that wouldn’t be able to hold the balls in the robot without outside support (e.g. there isn’t anything stopping the balls from falling out the bottom of the ramp/tube), would this count towards the 15 ball limit?

A: Balls in a tube, or on a ramp would be considered controlled by the robot and are subject to the limits of <SG15>.

A: The later posting will take precedence. Of the two answers given, the one you listed as "1st (GDC Twinkletoes)" was posted on 11/10/11, the one listed as "2nd (GDC Medic)" was posted 10/06/11.

[Raj]

Our team was working on our ball collection system and were wondering if we could use sensors and programming to limit the number of racquetballs we had collected. For example, if our robot had the physical capacity for more than 15 balls, but we programmatically (using sensors) made sure that the robot would never collect more than 15 balls. (Basically can we programmatically reduce our ball capacity)

A: No, this would be a violation of Rule <SG15> specifically the last statement in parentheses "if the ball holding capability of your robot can hold 16 or more balls, the Robot will not pass inspection"

[Wil Wheaton]

Our Robot has a an Archimedes screw which has 5 levels to pick up the racquet balls. The entry point where ball can enter is a 3 inch square and hence only one ball can get it in at a time. The height of the screw is 15 inches and the space between each step of the screw is 3 inches. Because of the restriction at the entry point, at any point of time, each rotation of the screw can only pick up one racquet ball. With five levels, the maximum capacity of the archimedes screw is 5 racquet balls at a time. At the last qualifier round, we were asked a lot of questions as the inspectors assumed that it was possible to carry many racquet ball in each level hence exceeding the 15 ball limit. We need your response that based on the information provided by us , our archimedes screw is within the rule limitations.

Are wood screws less than 3/8inch diameter allowed?

A1: The inspectors (and the referees) will determine if a robot is capable of holding more than the allowed 15 balls, based on their observations at the event.

A2: Wood screws are not allowed.