📃 Adds more docs

docs/motion_system.md

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+# 🏁 Motion state controller
+
+The motion controller is a finite state machine with state allowing for static and dynamic posing, 8-phase crawl and bezier bases trot gait, and choreographed animation.
+
+## Controller Input Mapping
+
+The controller input is interpret different between the modes. For the walking it it looks like this:
+
+| Controller Input | Mapped to Gait Step | Range   |
+| ---------------- | ------------------- | ------- |
+| Left x joystick  | Step x              | -1 to 1 |
+| Left y joystick  | Step z              | -1 to 1 |
+| Right x joystick | Step angle          | -1 to 1 |
+| Right y joystick | Body pitch angle    | -1 to 1 |
+| Height slider    | Body height         | 0 to 1  |
+| Speed slider     | Step velocity       | 0 to 1  |
+| S1 slider        | Step height         | 0 to 1  |
+| Stop button      | E stop command      | 0 or 1  |
+
+<!-- ### Static and dynamic posing -->
+
+## Walking gait
+
+General about walking gait
+
+Time step
+
+Phase condition
+
+Stance and swing controller
+
+## 8-phase crawl gait
+
+The 8-phase crawl gait works by lifting one leg at a time while shifting its body weight away from the leg.
+
+As the name implies, the gait consist of 8 discrete phases, which represents which feet should be contact the ground or be in swing.
+
+At each time step the phase time $t\in [0,1]$ is updated. When $t\geq 1$ the phase index is updated and phase time is reset.
+
+Is derived from [mike4192 spotMicro](https://github.com/mike4192/spotMicro)
+
+## Trot gait (12 point bezier curve)
+
+The trot gait implements a phase time $t\in[0,1]$, but instead of using contact phases we define a swing/stance ratio of phase time offset for each leg.
+
+The stance controller implements a sin curve to control the depth of steps.
+
+The swing controller implements a bezier curve using 12 control points centered around the robot leg.
+
+Rotation is calulated using the same curve