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Task

The ball physics model is meant to do things ... [TODO]


Table of Contents

Ball trajectory

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The trajectory of a ball can be modeled to be parabolic.



like so: .... [TODO]

Configuration

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Prediction parameters

ParameterDescriptionDefault value
PREDICTION_FRAME

window size for prediction - How far

into the future are predctions calculated at most.

70ms
PREDICTION_STEP_SIZE

size of the steps for the forward search

10ms
REFINEMENT_FACTOR

The prediction step size for the reverse search is
PREDICTION_STEP_SIZE divided by REFINEMENT_FACTOR.

10

with the default values up to 7 predictions are calculated if the ball is not predicted to be in flipper range roughly within the next two frames.


So this number is also the worst case number of predictions calculated during the reverse search part of the prediction process.

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Flipper range

The model of the area, where the the flippers can hit a ball is computed from a set of five points. These points are set to real world coordinates in meter

and should not need further adjustment after the camera is correctly calibrated (see World Coordinate System).

The values for the left flipper are set to be symmetrical.

Approximate positions of the points of interest

Point#Description
1

center point of the circle that the flippers tip moves o

2highest point a ball can be at when it hits the resting flipper
3lowest point a ball can be at when it hits the resting flipper
4lowest point a ball can be at when it hits the fully triggered flipper
5highest point a ball can be at when it hits the fully triggered flipper

Flipper range


From the aforementioned pointsFrom these points an area, where the ball is deemed to be hittable, is computed.

Flipper rangeImage Modified


Inlane Area

Image Removed

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Since the trajectory prediction does not consider collisions in general, we need a different kind of predictions for the inlanes,
i.e. the path feeding a falling ball from the playfield to the flippers, behind the slingshot.
A ball is considered to be in an inlane, when it is in a rectangualar area, with one edge given by the begin of the flipper
and the other by a point at highest, outermost position of the angled part of the inlane.

Image Added