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wrote intro text for proprioception
author Robert McIntyre <rlm@mit.edu>
date Tue, 14 Feb 2012 00:37:42 -0700
parents df46a609fed9
children f4b67005b702
rev   line source
rlm@157 1 #+title: The Sense of Proprioception
rlm@157 2 #+author: Robert McIntyre
rlm@157 3 #+email: rlm@mit.edu
rlm@157 4 #+description: proprioception for simulated creatures
rlm@157 5 #+keywords: simulation, jMonkeyEngine3, clojure
rlm@157 6 #+SETUPFILE: ../../aurellem/org/setup.org
rlm@157 7 #+INCLUDE: ../../aurellem/org/level-0.org
rlm@157 8
rlm@257 9 * Proprioception
rlm@257 10
rlm@257 11 Close your eyes, and touch your nose with your right index finger. How
rlm@257 12 did you do it? You could not see your hand, and neither your hand nor
rlm@257 13 your nose could use the sense of touch to guide the path of your hand.
rlm@257 14 There are no sound cues, and Taste and Smell certainly don't provide
rlm@257 15 any help. You know where your hand is without your other senses
rlm@257 16 because of Proprioception.
rlm@257 17
rlm@257 18 Humans can sometimes loose this sense through viral infections or
rlm@257 19 damage to the spinal cord or brain, and when they do, they loose the
rlm@257 20 ability to control their own bodies without looking directly at the
rlm@257 21 parts they want to move. In [[http://en.wikipedia.org/wiki/The_Man_Who_Mistook_His_Wife_for_a_Hat][The Man Who Mistook His Wife for a Hat]],
rlm@257 22 a woman named Christina looses this sense and has to learn how to move
rlm@257 23 by carefully watching her arms and legs. She describes proprioception
rlm@257 24 as the "eyes of the body, the way the body sees itself".
rlm@257 25
rlm@257 26 Proprioception in humans is mediated by [[http://en.wikipedia.org/wiki/Articular_capsule][joint capsules]], [[http://en.wikipedia.org/wiki/Muscle_spindle][muscle
rlm@257 27 spindles]], and the [[http://en.wikipedia.org/wiki/Golgi_tendon_organ][Golgi tendon organs]]. These measure the relative
rlm@257 28 positions of each pody part by monitoring muscle strain and length.
rlm@257 29
rlm@257 30 It's clear that this is a vital sense for fulid, graceful
rlm@257 31 movement. It's also particurally easy to implement in jMonkeyEngine.
rlm@257 32
rlm@257 33 My simulated proprioception calculates the relative angles of each
rlm@257 34 joint from the rest position defined in the blender file. This
rlm@257 35 simulates the muscle-spindles and joint capsules. I will deal with
rlm@257 36 Golgi tendon organs, which calculate muscle strain, in the [[./movement.org][next post]].
rlm@257 37
rlm@257 38 * Helper Functions
rlm@257 39
rlm@257 40
rlm@257 41 #+name: helpers
rlm@157 42 #+begin_src clojure
rlm@257 43 (in-ns 'cortex.proprioception)
rlm@157 44
rlm@173 45 (defn right-handed?
rlm@173 46 "true iff the three vectors form a right handed coordinate
rlm@257 47 system. The three vectors do not have to be normalized or
rlm@257 48 orthogonal."
rlm@173 49 [vec1 vec2 vec3]
rlm@157 50 (< 0 (.dot (.cross vec1 vec2) vec3)))
rlm@157 51
rlm@173 52 (defn absolute-angle
rlm@173 53 "The angle between 'vec1 and 'vec2. Positive if the angle to get
rlm@173 54 from 'vec1 to 'vec2 is counterclockwise around 'axis, and negative
rlm@173 55 otherwise."
rlm@173 56 [vec1 vec2 axis]
rlm@157 57 (let [angle (.angleBetween vec1 vec2)]
rlm@157 58 (if (right-handed? vec1 vec2 axis)
rlm@157 59 angle (- (* 2 Math/PI) angle))))
rlm@257 60 #+end_src
rlm@157 61
rlm@257 62 #+name: proprioception
rlm@257 63 #+begin_src clojure
rlm@257 64 (defn proprioception-kernel
rlm@173 65 "Returns a function which returns proprioceptive sensory data when
rlm@173 66 called inside a running simulation."
rlm@173 67 [#^Node parts #^Node joint]
rlm@157 68 (let [[obj-a obj-b] (joint-targets parts joint)
rlm@157 69 joint-rot (.getWorldRotation joint)
rlm@157 70 x0 (.mult joint-rot Vector3f/UNIT_X)
rlm@157 71 y0 (.mult joint-rot Vector3f/UNIT_Y)
rlm@157 72 z0 (.mult joint-rot Vector3f/UNIT_Z)]
rlm@157 73 (println-repl "x:" x0)
rlm@157 74 (println-repl "y:" y0)
rlm@157 75 (println-repl "z:" z0)
rlm@157 76 (println-repl "init-a:" (.getWorldRotation obj-a))
rlm@157 77 (println-repl "init-b:" (.getWorldRotation obj-b))
rlm@157 78
rlm@157 79 (fn []
rlm@157 80 (let [rot-a (.clone (.getWorldRotation obj-a))
rlm@157 81 rot-b (.clone (.getWorldRotation obj-b))
rlm@157 82 x (.mult rot-a x0)
rlm@157 83 y (.mult rot-a y0)
rlm@157 84 z (.mult rot-a z0)
rlm@157 85
rlm@157 86 X (.mult rot-b x0)
rlm@157 87 Y (.mult rot-b y0)
rlm@157 88 Z (.mult rot-b z0)
rlm@157 89 heading (Math/atan2 (.dot X z) (.dot X x))
rlm@157 90 pitch (Math/atan2 (.dot X y) (.dot X x))
rlm@157 91
rlm@157 92 ;; rotate x-vector back to origin
rlm@157 93 reverse
rlm@157 94 (doto (Quaternion.)
rlm@157 95 (.fromAngleAxis
rlm@157 96 (.angleBetween X x)
rlm@157 97 (let [cross (.normalize (.cross X x))]
rlm@157 98 (if (= 0 (.length cross)) y cross))))
rlm@157 99 roll (absolute-angle (.mult reverse Y) y x)]
rlm@157 100 [heading pitch roll]))))
rlm@157 101
rlm@173 102 (defn proprioception!
rlm@173 103 "Endow the creature with the sense of proprioception. Returns a
rlm@173 104 sequence of functions, one for each child of the \"joints\" node in
rlm@173 105 the creature, which each report proprioceptive information about
rlm@173 106 that joint."
rlm@157 107 [#^Node creature]
rlm@157 108 ;; extract the body's joints
rlm@257 109 (let [senses (map (partial proprioception-kernel creature)
rlm@173 110 (joints creature))]
rlm@157 111 (fn []
rlm@157 112 (map #(%) senses))))
rlm@257 113 #+end_src
rlm@175 114
rlm@257 115 #+name: visualize
rlm@257 116 #+begin_src clojure
rlm@257 117 (in-ns 'cortex.proprioception)
rlm@175 118
rlm@175 119 (defn draw-sprite [image sprite x y color ]
rlm@175 120 (dorun
rlm@175 121 (for [[u v] sprite]
rlm@175 122 (.setRGB image (+ u x) (+ v y) color))))
rlm@175 123
rlm@175 124 (defn view-angle
rlm@175 125 "create a debug view of an angle"
rlm@175 126 [color]
rlm@175 127 (let [image (BufferedImage. 50 50 BufferedImage/TYPE_INT_RGB)
rlm@175 128 previous (atom [25 25])
rlm@175 129 sprite [[0 0] [0 1]
rlm@175 130 [0 -1] [-1 0] [1 0]]]
rlm@175 131 (fn [angle]
rlm@175 132 (let [angle (float angle)]
rlm@175 133 (let [position
rlm@175 134 [(+ 25 (int (* 20 (Math/cos angle))))
rlm@175 135 (+ 25 (int (* -20 (Math/sin angle))))]]
rlm@175 136 (draw-sprite image sprite (@previous 0) (@previous 1) 0x000000)
rlm@175 137 (draw-sprite image sprite (position 0) (position 1) color)
rlm@175 138 (reset! previous position))
rlm@175 139 image))))
rlm@175 140
rlm@190 141
rlm@190 142 (defn proprioception-display-kernel
rlm@190 143 "Display proprioception angles in a BufferedImage"
rlm@190 144 [[h p r]]
rlm@190 145 (let [image (BufferedImage. 50 50 BufferedImage/TYPE_INT_RGB)
rlm@190 146 previous-heading (atom [25 25])
rlm@190 147 previous-pitch (atom [25 25])
rlm@190 148 previous-roll (atom [25 25])
rlm@190 149
rlm@190 150 heading-sprite [[0 0] [0 1] [0 -1] [-1 0] [1 0]]
rlm@190 151 pitch-sprite [[0 0] [0 1] [0 -1] [-1 0] [1 0]]
rlm@190 152 roll-sprite [[0 0] [0 1] [0 -1] [-1 0] [1 0]]
rlm@190 153 draw-angle
rlm@190 154 (fn [angle sprite previous color]
rlm@190 155 (let [angle (float angle)]
rlm@190 156 (let [position
rlm@190 157 [(+ 25 (int (* 20 (Math/cos angle))))
rlm@190 158 (+ 25 (int (* -20 (Math/sin angle))))]]
rlm@190 159 (draw-sprite image sprite (@previous 0) (@previous 1) 0x000000)
rlm@190 160 (draw-sprite image sprite (position 0) (position 1) color)
rlm@190 161 (reset! previous position))
rlm@190 162 image))]
rlm@190 163 (dorun (map draw-angle
rlm@190 164 [h p r]
rlm@190 165 [heading-sprite pitch-sprite roll-sprite]
rlm@190 166 [previous-heading previous-pitch previous-roll]
rlm@190 167 [0xFF0000 0x00FF00 0xFFFFFF]))
rlm@190 168 image))
rlm@190 169
rlm@190 170 (defn view-proprioception
rlm@190 171 "Creates a function which accepts a list of proprioceptive data and
rlm@190 172 display each element of the list to the screen as an image."
rlm@175 173 []
rlm@190 174 (view-sense proprioception-display-kernel))
rlm@257 175 #+end_src
rlm@175 176
rlm@257 177 #+name: proprioception-header
rlm@257 178 #+begin_src clojure
rlm@257 179 (ns cortex.proprioception
rlm@257 180 "Simulate the sense of proprioception (ability to detect the
rlm@257 181 relative positions of body parts with repsect to other body parts)
rlm@257 182 in jMonkeyEngine3. Reads specially prepared blender files to
rlm@257 183 automatically generate proprioceptive senses."
rlm@257 184 (:use (cortex world util sense body))
rlm@257 185 (:use clojure.contrib.def)
rlm@257 186 (:import com.jme3.scene.Node)
rlm@257 187 (:import java.awt.image.BufferedImage)
rlm@257 188 (:import (com.jme3.math Vector3f Quaternion)))
rlm@157 189 #+end_src
rlm@157 190
rlm@206 191 #+name: test-body
rlm@206 192 #+begin_src clojure
rlm@206 193 (defn test-proprioception
rlm@206 194 "Testing proprioception:
rlm@206 195 You should see two foating bars, and a printout of pitch, yaw, and
rlm@206 196 roll. Pressing key-r/key-t should move the blue bar up and down and
rlm@206 197 change only the value of pitch. key-f/key-g moves it side to side
rlm@206 198 and changes yaw. key-v/key-b will spin the blue segment clockwise
rlm@206 199 and counterclockwise, and only affect roll."
rlm@206 200 []
rlm@206 201 (let [hand (box 0.2 1 0.2 :position (Vector3f. 0 0 0)
rlm@206 202 :mass 0 :color ColorRGBA/Green :name "hand")
rlm@206 203 finger (box 0.2 1 0.2 :position (Vector3f. 0 2.4 0)
rlm@206 204 :mass 1 :color ColorRGBA/Red :name "finger")
rlm@206 205 joint-node (box 0.1 0.05 0.05 :color ColorRGBA/Yellow
rlm@206 206 :position (Vector3f. 0 1.2 0)
rlm@206 207 :rotation (doto (Quaternion.)
rlm@206 208 (.fromAngleAxis
rlm@206 209 (/ Math/PI 2)
rlm@206 210 (Vector3f. 0 0 1)))
rlm@206 211 :physical? false)
rlm@206 212 joint (join-at-point hand finger (Vector3f. 0 1.2 0 ))
rlm@206 213 creature (nodify [hand finger joint-node])
rlm@206 214 finger-control (.getControl finger RigidBodyControl)
rlm@206 215 hand-control (.getControl hand RigidBodyControl)]
rlm@206 216
rlm@206 217
rlm@206 218 (let
rlm@206 219 ;; *******************************************
rlm@206 220
rlm@206 221 [floor (box 10 10 10 :position (Vector3f. 0 -15 0)
rlm@206 222 :mass 0 :color ColorRGBA/Gray)
rlm@206 223
rlm@206 224 root (nodify [creature floor])
rlm@206 225 prop (joint-proprioception creature joint-node)
rlm@206 226 prop-view (proprioception-debug-window)
rlm@206 227
rlm@206 228 controls
rlm@206 229 (merge standard-debug-controls
rlm@206 230 {"key-o"
rlm@206 231 (fn [_ _] (.setEnabled finger-control true))
rlm@206 232 "key-p"
rlm@206 233 (fn [_ _] (.setEnabled finger-control false))
rlm@206 234 "key-k"
rlm@206 235 (fn [_ _] (.setEnabled hand-control true))
rlm@206 236 "key-l"
rlm@206 237 (fn [_ _] (.setEnabled hand-control false))
rlm@206 238 "key-i"
rlm@206 239 (fn [world _] (set-gravity world (Vector3f. 0 0 0)))
rlm@206 240 "key-period"
rlm@206 241 (fn [world _]
rlm@206 242 (.setEnabled finger-control false)
rlm@206 243 (.setEnabled hand-control false)
rlm@206 244 (.rotate creature (doto (Quaternion.)
rlm@206 245 (.fromAngleAxis
rlm@206 246 (float (/ Math/PI 15))
rlm@206 247 (Vector3f. 0 0 -1))))
rlm@206 248
rlm@206 249 (.setEnabled finger-control true)
rlm@206 250 (.setEnabled hand-control true)
rlm@206 251 (set-gravity world (Vector3f. 0 0 0))
rlm@206 252 )
rlm@206 253
rlm@206 254
rlm@206 255 }
rlm@206 256 )
rlm@206 257
rlm@206 258 ]
rlm@206 259 (comment
rlm@206 260 (.setCollisionGroup
rlm@206 261 (.getControl hand RigidBodyControl)
rlm@206 262 PhysicsCollisionObject/COLLISION_GROUP_NONE)
rlm@206 263 )
rlm@206 264 (apply
rlm@206 265 world
rlm@206 266 (with-movement
rlm@206 267 hand
rlm@206 268 ["key-y" "key-u" "key-h" "key-j" "key-n" "key-m"]
rlm@206 269 [10 10 10 10 1 1]
rlm@206 270 (with-movement
rlm@206 271 finger
rlm@206 272 ["key-r" "key-t" "key-f" "key-g" "key-v" "key-b"]
rlm@206 273 [1 1 10 10 10 10]
rlm@206 274 [root
rlm@206 275 controls
rlm@206 276 (fn [world]
rlm@206 277 (.setTimer world (com.aurellem.capture.RatchetTimer. 60))
rlm@206 278 (set-gravity world (Vector3f. 0 0 0))
rlm@206 279 (light-up-everything world))
rlm@206 280 (fn [_ _] (prop-view (list (prop))))]))))))
rlm@206 281
rlm@206 282 #+end_src
rlm@206 283
rlm@206 284
rlm@157 285 * COMMENT generate source
rlm@157 286 #+begin_src clojure :tangle ../src/cortex/proprioception.clj
rlm@257 287 <<proprioception-header>>
rlm@257 288 <<helpers>>
rlm@157 289 <<proprioception>>
rlm@257 290 <<visualize>>
rlm@157 291 #+end_src