# Speedbump on ramp clarification

My team and I are interested in knowing whether speedbumps are allowed on ramps. In the rules regarding ramps, it states that ramps have a maximum angle of 25 degrees above horizontal. Wouldn’t putting a speedbump on the ramp mean that the angle is now greater than 25 degrees? Regarding stairs it states that a plate would be used to measure the angle, and applying that to ramps, if there is a speedbump, a plate placed on it would have a greater than 25 degree tilt. Please refer to my diagram if my explanation is unclear in any way.

Hi Nayr,

Good question. Although there may be speedbump with <=2cm height on the ramp, it will be positioned high enough on the slope that it will never exceed 25degree incline (±10% variation, i.e. 27.5 degrees incline).

Elizabeth Mabrey
2023 Rescue Committee

Can I know the point of regulating the angle measured from the bottom of the ramp?
I think the robot will lean the same amount when passing over a speed bump wheter it is installed at the top of the ramp or at the bottom.

If my decades old trigonometry understanding works right, I am certain it should be relatively to the center of gravity of the robot. Thus, the incline angle is different based on the placement.

Hello @elizabeth.mabrey

there may be speedbump with <=2cm height on the ramp, it will be positioned high enough on the slope that it will never exceed 25degree incline (±10% variation, i.e. 27.5 degrees incline).

You wrote that the maximum angle is 25 degrees, including ramps and speed bumps on ramps.
Is this an official answer from the Rescue Committee including other committee members?

Regards,
MASA

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the current rule is sufficient… not “exceeding 25 degrees incline with ±10% error margin”.

referring to the quote you mentioned. I will definitely have to verify it doing some physics thinking to verify. No matter what . “exceeding 25 degrees incline with ±10% error margin” will always stay true.

Hello @elizabeth.mabrey

I will ask that again on another occasion.

Q.1

Reascue Maze 2023
2.1.4. They will have an incline with a maximum of 25 degrees from the horizontal

Rule 2.1.6 stipulates that the maximum slope angle is 25 degrees.
If there is a speed bump on the ramp, which is the slope angle, A or B?

Q.2
Is the answer to Q1 the same for Rescue Line and Rescue Maze?

Regards,
MASA

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Hi @Nayr and @MASA,

sorry for the confusion caused by conflicting replies earlier. The short answer is, the speed bumps will NOT affect the calculated angle of the ramp section, neither in Line nor in Maze.

See these rules:

Line:

• 2.7.1. Tiles will be used as ramps to allow the robots to ‘climb’ up and down from different levels.
• 2.7.2. Ramps will not exceed an incline of 25 degrees from the horizontal.
• 2.7.5. The line along the ramps can contain gaps, speed bumps and debris.

Maze:

• 2.1.4 Tiles will be used as ramps. They will have an incline with a maximum of 25 degrees from the horizontal and are always straight.

Note that in both cases the inclination is only mentioned in terms of the tile/ramp and not anything that might be placed on top of the tile/ramp. This is excluded in the calculation of the inclination.
Also note the ±10% tolerance on all values in the rules.

As @Ryo demonstrated with his drawings, the actual angle the robot will be subjected to, is dependent on the robot’s wheelbase and not only on the distance of the speed bump from the ramp’s starting point. As this parameter is outside the control of the field designers, it is not taken into account when determining the angle of the ramp section.

So referring to the scenarios presented by @MASA, in Q1 angle A is the relevant angle to not exceed the 25° incline. To Q2, yes, this applies to both Line and Maze.

Please let me know if you have follow-up questions.

Best,
Tom

2023 RCJ Rescue Committee Chair

Hi, I have a question regarding ramps. Are they going to be like the ones at the European Robocup (like remaining inside the same perimeter of the maze and the lenght of the ramp is a tile long) or they will connect multiple sections ( like a meter long ramp connecting multiple mazes). Sorry if I am not very clear.
Thank you,
Tuca.

Please look at this thread, as we explain better there the ramp situation: Is there a max amount of ramps and levels in an arena? - RoboCupJunior Rescue / RoboCupJunior Rescue Maze - RoboCupJunior Forum

Thanks,

Diego Garza Rodriguez
2023 Committee