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# Appearance Specifications

Modified today by tanij

Nothing.

Knowledge of the Duckietown appearance specifications

This document describes the Duckietown appearance specification. Specifications are a set of rules for which a functional system has been verified. This means that if these rules are followed while building a Duckietown, Duckiebots will (most probably!) work.

Any Duckietown not adhering to the rules described here cannot be considered a Duckietown, and may cause the Duckiebots operating within them to fail in unexpected ways.

Small perturbations to the appearance specifications might affect negatively the performance of Duckiebots, although most algorithms are robust to variations.

## Layer 1 - The Floor Layer

Modified today by tanij

The floor layer is made of interlocking black tiles. Each tile represents one road element: straight, curve, 3-way intersection, 4-way intersection and empty tile. The road elements are positioned in specific orders to create compliant Duckietowns. The road elements are shown in Figure 2.2, note that the left turn and right turn tiles are symmetric: one is the 90 degree rotation of the other.

Each tile is square and measures 61 x 61 cm (2 ft x 2 ft) from the outer edges of the interlocking dents. The thickness of the tiles is not as important as the surface roughness. The objective is having good grip between the Duckiebots and the road in order to minimize slipping of the wheels.

The empty tiles can be of any color, although it is discouraged to use the same colors as the road markings (red, white and yellow).

For tiles to become road elements, we need to apply road markings. Road markings can be obtained through the application of tapes of different colors and sizes.

### Tapes

Modified yesterday by tanij

There are 3 colors of tapes used in Duckietown: white, yellow, and red.

A Duckiebot on a road never collides with Duckiebots or other Duckietown elements if it never crosses or touches a white tape strip.

Here are some facts about the white tapes:

• White tapes must be solid (not dashed);

• The width of the white tape is roughly 4.8 cm (1.88 inches);

• The white tape is always placed on the right hand side of a lane. We assume that the Duckiebots drive on the right hand side of the road.

comment

this should be part of the “traffic rules” sections.

Here are some facts about the yellow tapes:

• Yellow tape must be dashed (not solid);

• Each piece should be 5 cm long and placed with a 2.5 cm gap between each piece;

• The width of the yellow tape is roughly 2.4cm (0.94 inches);

• The yellow tape is always placed on the left hand side of a lane, i.e., in the center of the road. We assume that the Duckiebots drive on the right hand side of the road.

Yellow tapes on curves: see curved road image (Figure 2.10) in white tape section. Pieces at tile edges should be in center of lane, piece at the middle of the curve should be approximately 20.5 cm from middle of inner center white piece of tape, with approximated circular arc in between.

Red tapes MAY only appear on intersection tiles.

The width of the red tape must be the same as the white roll (roughly 4.8cm or 1.88 inches) and should cross the entire lane perpendicular to the road.

The placement of red tape should always be under yellow and white tape, as shown, e.g., in Figure 2.6 or Figure 2.8.

A Duckiebot navigates Duckietown by a sequence of:

• Navigating one or more straight tiles until a red tape appears,
• Waiting for the coordination signal,
• Executing an intersection traversal,
• Re-localizing in a straight tile.
If the Duckiebot stops before or ON the red strip, no collisions are possible.

### Parking Lots

Modified today by tanij

The tile types described here are experimental. Use at your own risk!

A parking lot is a place for Duckiebots to go when they are tired and need a rest.

A parking lot introduces three additional tile types:

1. Parking spot tiles:
2. Parking spot access tiles:

TODO: the tape on the spot and spot access tiles is currently not yet specified.

task next (1 of 26) index

The following was marked as "todo".

TODO: the tape on the spot and spot access tiles is currently not yet specified.

File book/opmanual_duckietown/04-duckietown-appearance-specifications.md.

File book/opmanual_duckietown/04-duckietown-appearance-specifications.md
in repo duckietown/docs-opmanual_duckietown branch master commit 823b8286

Created by function create_notes_from_elements in module mcdp_docs.task_markers.

The following are the rules for a conforming parking lot:

1. One “parking spot” has size one tile.
2. From each parking spot, there is a path to go to the parking lot entry tile that does not intersect any other parking spot. (i.e. when a Duckiebot is parked, nobody will disturb it).
3. From any position in any parking spot, a Duckiebot can see at least two orthogonal lines or a sign with an April tag.

TODO: this point needs further specification

previous task next (2 of 26) index

The following was marked as "todo".

TODO: this point needs further specification

File book/opmanual_duckietown/04-duckietown-appearance-specifications.md.

File book/opmanual_duckietown/04-duckietown-appearance-specifications.md
in repo duckietown/docs-opmanual_duckietown branch master commit 823b8286

Created by function create_notes_from_elements in module mcdp_docs.task_markers.

### Launch Tiles

Modified today by tanij

The tile type described here is experimental. Use at your own risk!

A “launch tile” is used to introduce a new Duckiebot into a Duckietown in a controllable way. The launch file should be placed adjacent to a turn tile so that a Duckiebot may “merge” into Duckietown once the initialization procedure is complete.

TODO: Specification for tape on the launch tile

previous task next (3 of 26) index

The following was marked as "todo".

TODO: Specification for tape on the launch tile

File book/opmanual_duckietown/04-duckietown-appearance-specifications.md.

File book/opmanual_duckietown/04-duckietown-appearance-specifications.md
in repo duckietown/docs-opmanual_duckietown branch master commit 823b8286

Created by function create_notes_from_elements in module mcdp_docs.task_markers.

A “yield” sign should be visible from the launch tile.

## Traffic Signs

Modified today by tanij

Traffic signage in Duckietown in obtained through the union of a traffic signs and an April Tag, as shown in Figure 2.14

We call the symbol above traffic sign, while the code below is an AprilTag.

To print and assemble the signs refer to Unit B-2 - Traffic Signs Assembly.

### Placement

Modified today by tanij

Modified today by tanij

Signs may appear on the opposite side and at the corner of the adjacent tile from which they are viewed. In the absence of any signs, it is assumed that all network flows are allowed so a sign MUST be placed and visible whenever this is not the case.

Signs must only be placed on empty tiles, or next to one of the other tile types if on the border of a map. As mentioned, it is important to not overlap the base of the sign stand with any road marking.

The sign placements for four different cases are shown in Figure 2.18. At intersections, from each stop line 2 signs should be clearly visible: 1) the intersection type (traffic light or stop sign) and 2) the intersection topology (3-way with correct orientation, or 4-way).

On straight and curved roads, additional signs can be added as desired. Their placement is indicated in Figure 2.18f - straight road and Figure 2.18h - curved road. The signs should be placed at the border between two tiles and should face towards oncoming traffic as indicated.

In these figures the arrow is the direction of the sign.

## Street Name Signs

Modified 2018-06-22 by Andrea Censi

## Traffic Lights

Modified today by tanij

The assembly procedure for building the a traffic light is found in Unit B-3 - Traffic Lights Assembly.

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