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Changes for page Ball Physics

Last modified by Soeren Domroes on 2025/01/30 12:18
From version 3.1
edited by stu104225
on 2020/03/03 18:55
Change comment: There is no comment for this version
To version 7.1
edited by stu104225
on 2020/03/06 18:02
Change comment: There is no comment for this version

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... ... @@ -1,55 +1,130 @@
1 +The **ball physics model**'s main objective is to provide a point in time to the controller, when the ball is predicted to be hittable, in order to not let the ball fall into the drain.
2 +
1 1  \\
2 2  
3 -== Task ==
5 +\\
4 4  
5 -The ball physics model is meant to do things ...
6 6  
7 -\\
8 8  
9 -== Configuration ==
9 +{{toc/}}
10 10  
11 -=== Points of interest ===
11 +== Ball trajectory ==
12 12  
13 +----
14 +
15 +The trajectory of a ball can be modeled to be parabolic.
16 +
13 13  \\
14 14  
15 -[[image:attach:physics_points.png]]
16 16  
17 -=== Flipper range ===
20 +\\\\like so: .... [TODO]
18 18  
19 -\\
22 +== Configuration ==
20 20  
21 -\\
24 +----
22 22  
23 -\\
26 +=== Prediction parameters ===
24 24  
25 -\\
28 +(% class="wrapped" %)
29 +|=(((
30 +Parameter
31 +)))|=(((
32 +Description
33 +)))|=(((
34 +Default value
35 +)))
36 +|(((
37 +PREDICTION_FRAME
38 +)))|(((
39 +window size for prediction - How far
26 26  
27 -[[image:attach:physics2.png]]
41 +into the future are predctions calculated at most.
42 +)))|(((
43 +70ms
44 +)))
45 +|(((
46 +PREDICTION_STEP_SIZE
47 +)))|(((
48 +size of the steps for the forward search
49 +)))|(((
50 +10ms
51 +)))
52 +|(((
53 +REFINEMENT_FACTOR
54 +)))|(((
55 +The prediction step size for the reverse search is
56 +PREDICTION_STEP_SIZE divided by REFINEMENT_FACTOR.
57 +)))|(((
58 +10
59 +)))
28 28  
29 -\\
61 +When setting the PREDICTION_FRAME keep in mind, that predictions, that reach multiple frames into the future, are likely to be overwritten, when new frames arrive and new predictions are calculated.
62 +Nevertheless it is reasonable to calculate predictions beyond the next frame in case a ball is not recognized on the next frame.
30 30  
31 -=== Inlane Area ===
64 +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.
32 32  
33 -[[image:attach:physics_inlane.png]]
66 +The REFINEMENT_FACTOR is also the worst case number of predictions calculated during the reverse search part of the prediction process.
34 34  
35 35  \\
36 36  
37 -=== Prediction parameters ===
70 +=== Flipper range ===
38 38  
39 -\\
72 +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
40 40  
41 -\\
74 +and should not need further adjustment after the camera is correctly calibrated (see [[doc:World Coordinate System]]).
42 42  
43 -\\
76 +The values for the left flipper are set to be symmetrical.
44 44  
45 -\\
78 +[[image:attach:physics_points.png]]
46 46  
47 -\\
80 +(% class="wrapped" %)
81 +|=(((
82 +Point#
83 +)))|=(((
84 +Description
85 +)))
86 +|(((
87 +1
88 +)))|(((
89 +center point of the circle that the flippers tip moves o
90 +)))
91 +|(((
92 +2
93 +)))|(((
94 +highest point a ball can be at when it hits the resting flipper
95 +)))
96 +|(((
97 +3
98 +)))|(((
99 +lowest point a ball can be at when it hits the resting flipper
100 +)))
101 +|(((
102 +4
103 +)))|(((
104 +lowest point a ball can be at when it hits the fully triggered flipper
105 +)))
106 +|(((
107 +5
108 +)))|(((
109 +highest point a ball can be at when it hits the fully triggered flipper
110 +)))
48 48  
49 49  \\
50 50  
51 -\\
114 +From these points an area, where the ball is deemed to be hittable, is computed.
52 52  
53 -\\
116 +[[image:attach:physics2.png]]
54 54  
55 55  \\
119 +
120 +=== Inlane Area ===
121 +
122 +Since the trajectory prediction does not consider collisions in general, we need a different kind of predictions for the inlanes,
123 +i.e. the path feeding a falling ball from the playfield to the flippers, behind the slingshot.
124 +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
125 +and the other by a point at highest, outermost position of the angled part of the inlane.
126 +
127 +In this area the vertical accelleration is deactivated in the prediction, since it would cause the prediction to assume the would slide into the wall.
128 +Though in reality the still is some accelleration, a simple linear prediction has shown to be practical in this less critical area.
129 +
130 +[[image:attach:physics_inlane.png]]
Confluence.Code.ConfluencePageClass[0]
Id
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1 -71401639
1 +71401657
URL
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1 -https://rtsys.informatik.uni-kiel.de/confluence//wiki/spaces/PP18/pages/71401639/Ball Physics
1 +https://rtsys.informatik.uni-kiel.de/confluence//wiki/spaces/PP18/pages/71401657/Ball Physics